ESKOM COEGA CCGT
144807.71.0201
WORKS INFORMATION
EMPLOYER REVIEW
20October06
01630 – System Descriptions
01630.1 Introduction
This section contains a system description for each of the systems that shall be constructed as part of the
Project. These system descriptions contain the function, major components, system description, and
basis for design for each system. Alternate arrangements that meet the overall Facility functional requirements will be considered.
01630.2 Electrical and Controls Systems
This section contains a system description for each of the major electrical and controls systems that will
be constructed as part of the Project. These system descriptions describe the function, major
components, and basis for design for each system.
Contractor shall coordinate transmission system operation, generator production, and utility metering with
the Employer. Employer shall review and approval the transmission system operations, generator
production, and utility metering.
The system descriptions contained within this section are as follows:
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01630.2.1
AC Power Supply (230/400 V) (APB)
AC Power Supply (400 V) (APC)
AC Power Supply (6600 V) (APD)
DC Power Supply (APH)
Uninterruptible Power Supply (API)
Emergency Power Black Start (6600 V) (APK)
Plant Intercommunications Paging (CMA)
Commercial Telephone (CMD)
Distributed Control System (COA)
Grounding (EEB)
Raceway (EEC)
Steam Turbine Generator Bus Duct (GTA)
Combustion Turbine Generator Circuit Breaker (GTO)
Generator Step-Up Transformer (GTU)
Combustion Turbine Generator Bus Duct (GTK)
Building Lighting (LTA)
Area Lighting (STH)
AC POWER SUPPLY (230 V) (APB)
Function
The AC Power Supply (230 V) System provides 230 volt single-phase power for 230 volt loads.
Major Components
The AC Power Supply (230 V) System will consist of the following major components:
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230 volt ac, single-phase panelboards.
General Description
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System Descriptions
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Power for the AC Power Supply (230 V) System shall be provided by the three phase, 4 wire AC Power
Supply (400 V) System switchboards and/or motor control centers. The 230 volt power shall be fed to
panelboards which contain circuit breakers for distribution of the 230 volt single-phase power. The
panelboards shall also provide branch circuit protection and a means of disconnect for the branch circuit
loads through manually operated thermal magnetic circuit breakers.
The AC Power Supply (230 V) System shall accommodate plant startup and be designed to meet 100
percent of the required continuous plant loads and provide 10 percent spare capacity for use during
commercial operation.
Low Voltage AC panelboards color shall be grey.
01630.2.2
AC POWER SUPPLY (400 V) (APC)
Function
The AC Power Supply (400 V) System provides 400 volt three-phase power for the 400 volt auxiliary
electric system and electric loads. The AC Power Supply System (400V) shall include overcurrent,
phase, ground fault protection, and fault recorders.
Major Components
The AC Power Supply (400 V) System will consist of the following major components:
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6600 volt to 400 volt switchgear transformers with solidly grounded secondary.
400 volt, three-phase, four-wire metal enclosed switchgear with metal enclosed, withdrawable
air circuit breakers.
400 volt, three-phase, four-wire motor control centers (MCC).
400 volt, three-phase, four-wire panelboards.
Maintenance Power System
HVAC Power and Control Panels
General Description
The AC Power Supply System is shown on One-Line Diagram 144807-CAPC-E1002.
The switchgear transformers shall receive power at 6600 volt, three-phase from the AC Power Supply
(6600V) System and transform it to 400 volt, three-phase power. The transformer 6600 volt primary shall
be connected delta. The 400 volt secondary of the switchgear transformers shall be connected solidly
grounded wye. Each indoor switchgear transformer shall be a dry type, resin encapsulated transformer
furnished with AA cooling rating, and an 80C temperature rise. Each outdoor switchgear transformer
shall be an oil-filled transformer furnished with an ONAN cooling rating and a 65C temperature rise.
Oil filled transformers shall be provided with containment sized to hold 110% of the oil reservoir capacity.
All switchgear transformers shall be provided with a no load tap changer.
Motor loads greater than or equal to 0.18kW and less than or equal to 160kW shall be fed from the 400
volt switchboards and/or MCCs.
All other loads shall receive power from 230 V panelboards.
Three 400V switchgears with incoming breakers shall be provided in the turbine building, one for each
combustion turbine/HRSG. Each switchgear shall receive power from the 6600V system via an
associated 400V switchgear transformer and transform the power to 400V for distribution to 400V loads
Source: 01630, 2005
System Descriptions
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and 400V motor control centers. The 400V switchgear shall be located indoors. Their respective 6600V
to 400V transformers shall be dry-type, resin encapsulated, and located indoors. Each switchgear shall
have tie breaker to an adjacent Unit’s 400V switchgear to allow operation with its incoming transformer
out of service. Therefore, each transformer shall be sized for the entire load of its associated switchgear
plus the load of the adjacent unit’s 400V switchgear it is tied to. The transformers shall be throatconnected to their associated low voltage switchgear lineups.
One 400V switchgear with two incomer breakers shall be provided at the circulating water intake. The
switchgear shall receive power from the 6600V switchgear via a 400V switchgear transformer and
transform the power to 400V for distribution to 400V loads and 400V motor control centers. The 400V
switchgear shall be located indoors. Their respective 6600V to 400V transformers shall be oil immersed
and located indoors. Each transformer shall be sized for the entire load of the associated switchgear.
The transformers shall be connected by either cable, bus duct, or cable bus to their associated low
voltage switchgear lineups.
One 400V switchgear with two incomer breakers shall be provided at the water treatment building area.
The switchgear shall receive power from the 6600V switchgear via a 400V switchgear transformer and
transform the power to 400V for distribution to 400V loads and 400V motor control centers. The 400V
switchgear shall be located indoors. Their respective 6600V to 400V transformers shall be dry-type and
located indoors. Each transformer shall be sized for the entire load of the associated switchgear. The
transformers shall be throat-connected to their associated low voltage switchgear lineups.
Motor Control Centers shall be provided as needed to distribute power to cyclic 400V loads, 400V
intermediate loads, and small 400V loads that require motor starters or are essential to plant operation.
Individual 400V MCCs shall be provided with spare starters and spare breakers as design permits.
Motor control centers in general shall be located indoors. It is anticipated that the following MCCs will be
required. Exact quantity and locations to be determined during detail design.
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Combustion Turbine 1 MCC 1 &2 (located in CT Supplier Control/Electrical Enclosure)
Combustion Turbine 2 MCC 1&2 (located in CT Supplier Control/Electrical Enclosure)
Combustion Turbine 3 MCC 1&2 (located in CT Supplier Control/Electrical Enclosure)
Steam Turbine MCC 1&2
Turbine Building Services MCC 1&2
Control Building Switchboard 1 & 2
HRSG 1 MCC 1
HRSG 2 MCC 1
HRSG 3 MCC 1
Water Treatment MCC 1 & 2
Hypochlorite/Hydrogen Generation MCC
Admin/Maintenance/Warehouse Shop MCC
Intake MCC 1 & 2
Desalination MCC 1 & 2
MCCs shall receive power from breakers in the 400V switchgear.
Each MCC shall contain combination full voltage type “2” co-ordination motor starters and molded case
circuit breakers. 400V Switchgear breakers to MCCs shall be electrically operated. All motor starters up
to an including 55kW shall be fully withdrawable.
The internal control voltage for the LV switchgear system shall be 220V dc supplied from two independent
station batteries (APH System) for controls and a 230V ac power supply for breaker spring charge.
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Protection of LV switchgear shall be in accordance with Generation Standard GGS0803, Generation MV
and LV Protection Philosophy for Power Stations.
Protection equipment shall be microprocessor based and shall conform to ESKASAA04 – Eskom
Standard for Electronic Protection and Fault Monitoring Equipment for Power Systems.
Switchgear load analysis, load study, fault analysis, and fault study shall be submitted to the Employer by
the Contractor to ensure the switchgear is properly sized and protected.
The interface to the LV switchgear to the station control system shall be with a redundant control system
communication bus network, providing the control and monitoring facilities to the operators in the control
room.
MCCs and 400V switchgear finish color shall be grey.
The AC Power Supply (400V) System shall be designed to feed the low voltage loads. Each Switchgear
transformer and associated low voltage switchgear line-up shall be sized to serve its maximum
coincidental operation load. Each single-ended lineup 400V Switchgear shall be provided with one
equipped space for the installation of an additional circuit breaker in the future. Each 400V MCC shall be
shipped from the manufacturer with spare starters, breakers, or spaces to allow for future growth.
The maintenance power system shall consist of circuit breakers that provide ground fault and overcurrent
protection, cables, raceways and switched socket outlets to provide power to maintenance equipment
rated above 16 amps. The switched socket outlets shall be of the 63 amp 5 pin type.
01630.2.3
AC POWER SUPPLY (6600 V) (APD)
Function
The AC Power Supply (6600 V) System provides a high resistance grounded power source to plant
auxiliaries requiring 6600 volt power. The AC Power Supply System (6600V) shall include overcurrent,
phase, ground fault protection, and fault recorders.
Major Components
The AC Power Supply (6600 V) System will consist of the following major components:
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Two two-winding delta primary, resistance grounded wye secondary 6.6 kV unit auxiliary
transformers (UAT). The unit auxiliary transformers shall each be provided with an off load
tap changer.
One neutral grounding resistor on the secondary of each unit auxiliary transformer.
Two Turbine Building 6600 volt metal-clad, internal arc proof certified Switchgears with main
breakers, feeder breakers and tie breakers.
6600 volt cable bus or non-segregated phase bus duct connection from each unit auxiliary
transformer to its respective switchgear lineup.
Remotely fed 6600V metal-clad, internal arc proof certified Switchgears with main breakers,
feeder breakers and tie breaker.
Transformer rail removal system (furnish only – shared with the generator step-up
transformers).
General Description
The AC Power Supply System is shown on the One-Line Diagram 144807-CAPF-E1001.
The AC Power Supply (6600 V) System shall receive three-phase power via the unit auxiliary
transformers from the generator bus via an isolated phase bus duct tap to each unit auxiliary transformer.
Source: 01630, 2005
System Descriptions
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The unit auxiliary transformer shall transform the high voltage to 6600 volts and deliver it to the 6600 volt
switchgear. The secondary winding (6600 V) of the transformer shall be high resistance grounded to limit
the maximum line to ground fault current.
The unit auxiliary transformer shall be furnished with an ODAF cooling rating.
The transformer shall be oil filled. An oil containment basin shall be provided. Drainage shall be routed to
an oil/water separator. Firewalls shall be provided if required by NFPA 850
The impedance and primary voltage rating of the unit auxiliary transformer shall be selected to enable
motor starting while limiting fault currents to the design levels.
Each switchgear lineup connected to the unit auxiliary transformers shall consist of one main circuit
breaker, two tie circuit breaker, and motor, transformer, and subfed switchgear feeder circuit breakers. It
shall distribute power to large motors and 400V switchgear transformers, combustion turbine starting
equipment (LCI), and feeds to the black start generation equipment (APK), and intake area switchgear.
All medium voltage switchgear shall be of the metal clad internal arc proof certified type in accordance
with IEC 56, 62271-100, 62271-200, and GGSS 1201 Rev. 1, Appendices AA – Criteria 1-6. Arc detection
for selective tripping shall be provided as part of the protection scheme. The switchgear arc venting
system shall be coordinated with the building systems to provide safe outlet of the arc gases out of the
switchgear building.
Each circuit shall be provided with a power cable earthing switch. Additionally, the switchgear bus shall
be provided with earthing switch. Mechanical interlocks shall be provided to prevent closing an earth
switch on a live power cable or bus bar.
The 6.6kV Switchgear shall be provided with spares and equipped spaces as noted on the one lines.
Medium voltage switchgear shall utilize multifunction microprocessor based electronic protective relays
for motor and feeder protection. Protection shall be in accordance with Employer Standard GGS0803
“Generation MV and LV Protection Philosophy for Power Stations”. Protection equipment shall be in
accordance with Eskom Standard for Electronic Protection and Fault Monitoring ESKASAA04.
Switchgear load analysis, load study, fault analysis, and fault study shall be submitted to the Employer by
the Contractor to ensure the switchgear is properly sized and protected.
The 6.6kV Switchgears powered from the unit auxiliary transformers shall be connected to the
transformer via cable bus or non-segregated phase bus duct.
6600 volt equipment interrupting rating shall be sufficient to interrupt the maximum fault current available.
The internal control voltage and breaker spring charge for the MV switchgear shall be 220V supplied from
the station batteries (APH System).
The interface to the Medium Voltage switchgear to the station control system shall be with a redundant
control system communication bus network, providing the control and monitoring facilities to the operators
in the control room.
Switchgear finish color shall be cream (RAL 2000)
The AC Power Supply (6600 V) System shall be designed to supply power for the maximum coincidental
load requirements. The unit auxiliary transformers maximum rating shall be sized for full load operation
with the other unit auxiliary transformer out of service and the tie breaker closed.
Source: 01630, 2005
System Descriptions
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A transformer rail removal system, complete with permanent foundations, shall be furnished to allow
removal of any unit auxiliary transformer from its foundation and transport it to the location of any other
unit auxiliary transformer. The rail removal system shall be designed to move the transformer in a fully
assembled state, without dismantling the transformer or draining the oil. The rail system shall be stored
when not in use. The Contractor shall design and install permanent foundations for support of the rail
system.
The Contractor’s design shall not preclude moving transformers between the Coega 3x1 block and the
future Coega 3x1 block.
01630.2.4
DC POWER SUPPLY (APH)
Function
The DC Power Supply System provides a reliable source of power for critical control and power functions
during normal and emergency operating conditions. Batteries shall be provided to provide power to the
Uninterruptible Power Supply (UPS) System, switchgear control power, control room lighting (backup
supply) and other critical loads.
Other DC systems to be provided include the Combustion Turbine Generator dc power supply system
(one per Combustion Turbine, located in its associated electrical/control package).
Major Components
The DC Power Supply System will consist of the following major components:
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Two 220 volt dc lead acid station batteries.
Two full-capacity redundant solid-state chargers per battery.
Main DC distribution panel (per battery).
General Description
The DC Power Supply System shall consist of a station battery system. The system shall utilize flooded
type batteries. These batteries provide DC power to critical BOP loads and control power for the auxiliary
electrical system equipment. Each battery shall be connected to a main distribution panel and
continuously charged by two fully redundant battery chargers.
Under normal conditions, the battery chargers supply dc power to the dc loads. The battery chargers
receive 400 volt ac power from the AC Power Supply (400V) System. The chargers shall continuously
float-charge the battery while supplying power to the dc loads. Under abnormal or emergency conditions
when 400 volt ac power is not available, the battery supplies dc power to the dc loads. Recharging of
discharged batteries occurs whenever 400 volt ac power becomes available. The rate of charge is
dependent upon the characteristics of the battery, battery chargers, and the connected dc load during
charging. Each station battery charger shall be sized to provide the normal continuous dc power
requirements while recharging the battery in less than 12 hours (24 hours if one charger is out of service).
The station battery shall be sized to safely shut down the power plant upon loss of all ac power, and
supply essential dc loads for a minimum of 240 minutes, or as required by the Steam Turbine equipment,
whichever is longer. The battery shall be located in a space conditioned area so that suitable
temperatures can be maintained, thus helping to ensure long battery life. The battery room shall be a fire
rated room and shall be provided with ventilation to prevent hydrogen buildup.
DC distribution panel finish color shall be red.
Source: 01630, 2005
System Descriptions
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The station battery system shall be sized in accordance with IEEE 485 to serve the loads assigned to that
battery. Battery rating shall account for aging of the cells and temperature differences. UPS System
Panelboards shall be provided with at least 10% spare breakers for future use.
01630.2.5
UNINTERRUPTIBLE POWER SUPPLY (API)
Function
The Uninterruptible Power Supply (UPS) System provides 230 volt ac, single-phase, 50 hertz power to
essential instrumentation and equipment loads that require non-interruptible ac power, including the DCS
system, switchgear control power supplies, building egress lighting, and control room normal lighting.
Major Components
The Uninterruptible Power Supply shall consist of the following major components:
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One full-capacity, 230 volt ac, single-phase, 50 hertz inverter.
One solid-state static transfer switch.
One manual bypass switch.
Essential service ac panelboards for distribution of 230 volt ac essential service power.
One alternate source transformer and voltage regulator.
General Description
The normal source of power for the UPS shall be from the DC Power Supply System. The full-capacity
inverter shall be connected to a 230 volt ac panelboard through a static transfer switch and a manual
bypass switch. The inverter shall be in a free-standing, floor-mounted enclosure and use solid-state
silicon controlled rectifier switching assemblies and other devices to invert dc to ac power. Protecting,
monitoring, regulating, and phasing devices shall be included with the inverter. During normal operation,
the inverter shall supply the essential ac loads.
A solid-state switch connected to the output of the inverter shall continuously monitor both the inverter
output and the alternate ac source. Upon loss of the inverter output, the static switch shall automatically
transfer essential ac loads without interruption from the inverter output to the alternate source. The power
supply for the alternate source transformer and regulator shall be the AC Power Supply (400 V) System.
During normal operation, the inverter-static switch-power panel combinations shall be dedicated to
furnishing the power required by the UPS. The AC Power Supply (400 V) System shall be utilized as a
backup to the inverter systems.
A manual bypass switch shall be provided to enable isolation of the inverter-static switch from service for
testing and maintenance without interruption to the UPS System loads.
UPS System loads shall be fed from the UPS ac panelboards through fast tripping circuit breakers or
fuses.
The inverter shall be maintained in synchronism with the alternate ac power source.
AC distribution panel finish color shall be grey.
The UPS System shall be designed to meet 110 percent of the maximum coincidental operating load.
UPS System Panelboards shall be provided with at least 10% spare breakers for future use.
01630.2.6
EMERGENCY POWER- BLACK START (6600 V) (APK)
Source: 01630, 2005
System Descriptions
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Function
Black Start System shall provide three-phase power directly to the AC Power Supply (6600 V) System,
and shall have the capability of starting one of the combustion turbines from shutdown, while utilizing no
external power sources.
Source: 01630, 2005
System Descriptions
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Major Components
The Black Start System shall include the following major components:
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Multiple diesel engine driven generators rated 6600 volt nominal, three-phase, 50Hz
Individual unit and overall digital control panels for automatic starting, stopping,
synchronizing, load sharing, and parallel operation of generator units locally and remotely
Electrically operated circuit breakers with generator and system protection for automatic
synchronizing of units during normal operation and testing
Fuel storage and automatic fuel feed system
Auxiliary equipment, instruments, and starting system required for start-up and operation
Interconnecting piping and wiring
General Description
The Emergency Power/Blackstart System is shown on One-Line Diagram 144807-CAPF-E1001.
In the event that power is not available from the system grid, Black Start System shall have the ability to
start, synchronize, and transfer power to the medium voltage switchgear automatically in order to provide
the required power to the auxiliary power system needed to start one of the combustion turbine
generators, from a shutdown state. Multiple diesel engine driven generators shall be utilized for this
purpose, in an N+1 configuration.
The system will be designed for operation of the critical loads for the duration necessary to allow the
combustion turbine generator to reach full power output, without the need for refueling. Each unit shall be
mounted on its own common steel base. The fuel system may be incorporated into the steel base, or
supplied as a separate system. Units shall be complete with transformers, motor starters, and electrical
control equipment required for operation. Transformers shall not be located in the same structure as the
diesel generator.
System design shall not preclude connection to the second 3x1 Coega CCGT block.
Automatic and manual start-up, control, and synchronizing shall be possible locally or remotely. Local
control shall be from an overall local control panel. Each unit shall have its own local control panel
connected to the overall panel. Failure of the overall control panel shall not shutdown the unit control
panels. Interconnecting piping and wiring for equipment mounted on the steel base shall be factory
installed.
During black start operation, the plant AC Power Supply (6600V) System shall receive power from the
generators. Configuration of the medium voltage switchgear, and low voltage switchgear breakers to
utilize the black start generator power shall not require manual opening and closing of main or tie feeder
breakers. Dedicated metering and protection, CTs, and VTs shall be used to allow interconnection of
buses to a dead bus or synchronization to a live bus. The Black Start System shall be capable of
completing a fully functional test of equipment and auxiliary systems while the plant is operating normally.
Each ground conductor from the generator shall be routed through an electrically operated contactor.
The contactor shall be normally closed and open when the generator is starting up and shall remain open
until the generator is synchronized to the system and then automatically/manually close.
All medium voltage switchgear shall be of the metal clad internal arc proof certified type in accordance
with IEC 56, 62271-100, and 62271-200, Appendices AA – Criteria 1-6. Arc detection for selective tripping
shall be provided as part of the protection scheme. The switchgear arc venting system shall be
coordinated with the building systems to provide safe outlet of the arc gases out of the switchgear
building.
Source: 01630, 2005
System Descriptions
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Each circuit shall be provided with a power cable earthing switch. Additionally, the switchgear bus shall
be provided with earthing switch. Mechanical interlocks shall be provided to prevent closing an earth
switch on a live power cable or bus bar.
The 6.6kV Switchgear shall be provided with spares and equipped spaces as noted on the one lines. Two
spare breakers shall be provided for future connection of the blackstart/emergency generation system to
the second 3x1 block.
Medium voltage switchgear shall utilize multifunction microprocessor based electronic protective relays
for motor and feeder protection. Protection shall be in accordance with Employer Standard GGS0803
“Generation MV and LV Protection Philosophy for Power Stations”. Protection equipment shall be in
accordance with Eskom Standard for Electronic Protection and Fault Monitoring ESKASAA04.
6600 volt equipment interrupting rating shall be sufficient to interrupt the maximum fault current available.
The internal control voltage and breaker spring charge for the MV switchgear shall be 220V dc for control,
supplied from the station batteries (APH System).
Interface to the station control system shall be with a redundant control system communication bus
network, providing the control and monitoring facilities to the operators in the control room.
Switchgear finish color shall be cream (RAL 2000).
01630.2.7
PLANT INTERCOMMUNICATIONS PAGING (CMA)
Function
The Plant Intercommunications Paging System shall provide the facility personnel with a plant wide
paging and alarm system.
Major Components
The Plant Intercommunication Paging System shall consist of the following major components:
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Handsets
Amplifiers.
Speakers and supports
Associated raceway and wiring.
General Description
The Plant Intercommunications Paging System shall be designed to provide a reliable, convenient
method of voice paging and alarm tones for facility personnel.
It shall accommodate a minimum of five (5) party lines. Handset/Speaker stations shall be located
throughout the plant facility. Installation locations include: the STG Electrical/Control enclosure, the
Packaged Electrical Electronic Control Compartment (PEECC) for each Combustion Turbine, each LCI
Compartment, Turbine Building, Heat Recovery Steam Generator area, Water Treatment Building, Diesel
Storage area, Circulating Water Intake structure, Hypochlorite Generfation Building, Hydrogen Generation
Building, Control Building, and Administration Building. Classified hazardous locations shall be provided
with equipment suitable for the environment.
01630.2.8
COMMERCIAL TELEPHONE (CMD)
Source: 01630, 2005
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Function
The Commercial Telephone System provides station personnel with reliable and convenient onsite and
offsite voice communication.
Major Components
The Commercial Telephone System shall consist of the following major components:
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Raceway and wiring shall be provided to the Control Building, Administration
Building, Maintenance Shop, and the Warehouse for the telephone system.
Main Distribution Frame and PABX located in the communications room in the
plant Admin building.
Intermediate Distribution Frame (IDF) enclosures shall be installed in the Control
Building, Maintenance Shop, and the Warehouse
Telephone handsets and stations.
General Description
The telephone system equipment will be provided by the Contractor. Wiring for the telephone outlets shall
be unshielded twisted pair Category 5 minimum Each building and enclosure noted above shall include
an Intermediate Distribution Frame (IDF) enclosure that shall be provided with suitable surge protection
fuses.
The Commercial Telephone System shall be designed to provide a reliable, convenient method of onsite
and offsite voice communications for facility personnel.
01630.2.9
DISTRIBUTED CONTROL SYSTEM (COA)
Function
The Distributed Control System (DCS) shall provide modulating control, digital control,
monitoring/indication, alarming, logging, data archiving, and indicating functions for the plant equipment.
Distributed I/O / process control cabinets (DCS cabinets) shall be interconnected via a redundant plant
data highway.
The DCS shall provide the following functions:
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Monitoring of plant equipment and process parameters and display of this information to the
plant operators in meaningful formats.
Overall control of plant output in a coordinated response to the load demands.
Control and monitoring of all plant equipment from the plant control room.
Operator control and monitoring interface through screen-based operator work stations
(OWS). Standard displays include process graphics (simplified P&ID), trend, and
permissives (active text). Control functions are implemented using pop-up stations on the
process graphic displays.
Visual/audible alarms for abnormal events based on field signals or software generated
signals (including out-of-limit parameters) from the systems, processes, and equipment.
Sequence-of-events (SOE) recording with 1 millisecond resolution to assist with diagnostic
evaluation of plant upsets and trips.
Historian for plant operating data archive and generation of operating and historical reports.
Built-in hardware and software diagnostics.
Engineering work station (EWS) for logic, tuning, and graphic additions, modifications, and
documentation.
Shift supervisor monitoring through a shift supervisor work station.
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Performance calculations.
Plant asset management system.
Remote diagnostic interface.
Remote web server interface.
Dual GPS time synchronization.
Major Components
The Distributed Control System shall include, but not be limited to the equipment described below:
 System equipment cabinets containing redundant processing units, redundant data highway
communications equipment, redundant datalink hardware, and redundant power supplies.
Processor memory utilization and duty cycle shall be 70 percent or less.
 I/O cabinets (or enclosures) containing the system input/output equipment and wiring
terminations for process sensing and equipment control interface. DCS terminations for
process sensing and equipment control interface.
 SOE input cards with one (1) millisecond resolution for critical inputs.
 Six (6) operator work stations, each with dual screen, keyboard and mouse to provide the
normal interface between the operator and the plant processes and equipment being
controlled or monitored. Alarm indications shall also be displayed on these screens.
 One (1) shift supervisor work station (a fully featured and functioning operator work station
with the exception that all control functions are disabled).
 Three (3) printers:
- One (1) color printer
- Two (2) laser printers
 One (1) engineer/operator work station (EWS) with dual screen, keyboard, and mouse to
provide the interface between the plant engineer and the plant processes and equipment for
control system tuning, and system program and screen graphic display modification and
development.
 Historian with long-term removable storage media and data storage, retrieval, and reporting
software.
 Standard redundant data highway to provide communication between the various
components of the DCS.
 Fully integrated control of all balance-of-plant functions and combustion turbine controls
 Redundant datalink communication interfaces are provided between the DCS and the
following listed equipment (time critical control data and trips for these interfaces shall be
hardwired):
- Steam turbine control system
- Power metering
- Low and medium voltage switchgear
- Sodium hypochlorite generation system
- Hydrogen generation system
- Desalination system
- Demineralizer system
- Water treatment systems
 Hardwired interfaces are provided between the DCS and the following listed equipment:
- Air compressor panel
- Automatic generation control (AGC) remote terminal unit (RTU)
- Each CEMS
 Operators' control console containing the DCS operator work stations, CEMS work station,
plant communications and security hardware, HRSG drum level indicators, and hardwired
emergency trip push buttons to allow tripping of major equipment independently of the DCS.
General Description
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The DCS shall be a microprocessor-based system composed of functionally distributed (modular)
processors, input/output modules, and operator interface devices, all connected via a redundant
communications network.
Screen-based work stations shall be provided for operation of the plant control systems as well as
providing alarm and data acquisition functions. All DCS displays and operator interface functions shall be
available on all screens. The work stations shall include keyboards and mouse for entering operatorinitiated control commands. Hardwired devices such as pushbuttons, switches and indicators shall be
provided as required by codes and regulations and for emergency shutdown.
The DCS shall include an overall minimum of 20 percent spare I/O capacity and equipment after field
commissioning is complete. Spare capacity shall be included for functional control for each processing
unit. Spare equipment shall include I/O cabinet terminal points and active I/O points.
The DCS design shall incorporate functional redundancy to ensure maximum reliability during system
operation. Redundant processing units shall be provided as required to ensure that a single point of
failure shall not result in loss of generation capacity. Where redundant processors are provided, one
processor of the pair shall be active; the other processor shall operate in a hot standby mode and shall be
continuously updated to be aware of the status of the active processor. In the event of a failure in the
active processor, all functions shall instantly be assumed by the standby processor. The transfer to the
standby processor shall be alarmed.
Redundant power supplies shall be provided for all control components in the system. Peripheral devices
such as printers shall be powered from the UPS. The DCS shall be equipped with a diagnostic package
that includes both hardware and software to detect system malfunction and equipment failure. The
occurrence of any malfunction or equipment failure shall be alarmed instantly. The diagnostic package
shall be capable of pinpointing the defective component down to the card level.
The DCS shall be designed to react in a predictable manner to certain failure:



Upon system logic failure, as detected by system diagnostics, a controller shall transfer to its
backup. If the backup is unavailable, the controller outputs shall fail to a predictable state
and shall enable any manual shutdown facilities which are appropriate to provide orderly
shutdown of equipment.
Upon system logic power supply failure, the controller shall transfer to its backup. If the
backup is unavailable, the system outputs shall fail to a de-energized state.
Upon power failure to an active or running controlled device or equipment, the system shall
react in a predetermined manner, either to command a restart of the equipment upon power
resumption, or to cycle the logic to a status requiring equipment shutdown.
The response time of the system shall be sufficient to maintain control over the plant processes under all
system operating conditions including extreme plant upset conditions with all points in alarm. The
response time is the total elapsed time for transmission of data through the system communication path.
This time shall include all communication time from processor to processor, I/O scans, nodes, gateways,
screens, keyboards, and associated equipment internal to the system.
Source: 01630, 2005
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WORKS INFORMATION
EMPLOYER REVIEW
20October06
GROUNDING (EEB)
Function
The Grounding System provides an adequate path to permit the dissipation of ground fault currents,
lightning induced potentials, and switching surges for protection of plant personnel and electrical
equipment.
Major Components
The Grounding System shall consist of the following major components:



Ground grid and ground loop conductors with stingers for attachment to metallic structures
and equipment.
Grounding rods.
Grounding connections.
General Description
A ground grid system consisting of bare stranded soft drawn copper conductors connected to copper-clad
ground rods shall be installed for the facility to provide a low resistance path to ground for fault currents,
lightning strikes, and other electrical current surges. The ground grid shall be buried beneath and around
all major plant buildings and structures. The grid shall be arranged in a rectangular pattern with spacing
between conductors determined by safe step potentials. The number, location, and depth of the ground
rods shall be determined by the soil resistivity and subsurface structural properties of the plant site.
All below grade connections between grounding conductors or between ground conductors and ground
rods shall be made using an exothermal welding process which fuses the two members together.
Two bare ground conductors shall be buried along the entire length of all below grade duct banks. All
onsite areas shall be connected to the plant ground grid with a minimum of two connections.
Bare copper ground "stingers" shall be connected to the grid and extended through the building floor
slabs to electrically connect the ground grid to building steel, support steel, large motors, electrical
switchgear, motor control centers, large power transformers, generators, and other equipment, including
Instrumentation junction boxes..
A copper grounding conductor shall be installed the entire length of power level cable trays, racks,
trenches, and wireways included in the Raceway System. Ground conductor for cable trays shall be
bolted to each tray section. The conductor shall be connected at various locations to the ground grid or
ground loop.
The Grounding System shall be designed with sufficient capacity to dissipate the ground current under
the most severe conditions and to maintain safe voltage gradients.
A low noise, isolated ground system shall be provided for grounding of sensitive electronic equipment
according to the manufacturer's instructions. This system shall consist of an insulated ground conductor
connected to the plant ground grid at one point. All signal grounds and other low level ground
connections shall be made to this dedicated copper. Other special grounding required by equipment
manufacturers shall be provided as necessary.
A lightning protection system shall be installed where required for plant structures. The structures
requiring lightning protection shall be determined during detailed design.
The design basis for the Grounding System shall be the, , NRS 042, IEC 6100-5-2, and IEC 60204-1. and
the applicable industry standards and practices. Minimum conductor sizes for earthing shall be as
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specified in Table 54F and paragraph 543.1.2 of IEC 364-5-54. Industry standards for safe step-andtouch potentials shall be paramount in design considerations.
The design basis for the Lightning Protection System shall be in accordance with NRS 042 and IEC
61000-5-2
Equipment shall be designed for EMC immunity and emissions properties compatible with the expected
environment in the plant. Where applicable, IEC product family standards shall be used instead of generic
standards. As a minimum, equipment shall be tested to pass the immunity requirements of IEC 61000-4
and ENV 50204 Standards. Equipment shall also meet CISPR 11 (EN-55011) and CISPR 22 (EN-55022)
requirements for EMC emissions.
01630.2.11
RACEWAY (EEC)
Function
The Raceway System provides support and protection for electrical power and control circuits between
various pieces of equipment, devices, and cabinets.
Major Components
The Raceway System shall consist of the following major components:







Cable tray.
Cable trenches and tunnels.
Wireway.
Duct bank.
Electrical manholes.
Cable drawpits/handholes.
Junction boxes and pull boxes.
General Description
A general description of the various components within the Raceway System is included below:
Cable Tray/Cable Racks--The cable tray/cable racks shall provide support to electrical cable which is
routed throughout the plant either directly to equipment or to areas of concentrated electrical loads.
Conduits--Conduits shall only be used to extend unarmoured cables from cable trays, band wireways to
equipment or cabinets, and for circuits between equipment and cabinets within buildings. (All cables
between buildings/enclosures should be armored.)
Wireways--Wireways shall provide an advantageous wiring transition between power panels or other
groupings of equipment. Wireways shall be oiltight, metallic wiring enclosures with hinged covers.
Direct Buried Conduit—For remote areas in the plant where a single power supply is required remote
from a cable tunnel or trench, cables can be installed in direct buried steel conduit or concrete encased
PVC conduit underground.
Electrical Manholes--Reinforced concrete manholes shall be provided, where required, so that cable may
be installed without exceeding allowable pulling tensions and cable sidewall pressures.
Junction Boxes/Pull Boxes--Junction boxes (terminal boxes) and pull boxes shall provide access to the
conduit system, serve as a transition from one type of raceway to another, and serve as circuit and
raceway collection points.
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Components of the Raceway System shall separate different types of cables to avoid electromagnetic
interference as required by equipment manufacturers. Maintain a separation of at least 600mm between
control cable and power cable rated up to 6.6kV, and 100mm between control cable and power cable
rated 11 kV.
All power cabling running between buildings shall be either to be run in suitable cable racks or trays
above ground, or in suitable cable tunnels. Direct buried cables are not acceptable. All piping runs
outside of main buildings shall be to be run in pipe tunnels, pipe trenches, or supported on suitable plinths
or racks above ground.
Large numbers of electrical and control cables are routed via tunnels and tenches with cable rack or
cable trays. There must be a separate cable rack or cable tray for the control cable (usually the top rack).
Where only a few cables are run for longer distances, buried conduit can be used. Control sleeves should
be at least 600mm away from LV and MV sleeves up to 6.6kV and 1000mm away for 11kV".
The design basis for the Raceway System shall be the Electrical Engineering Design Criteria section and
the applicable industry standards and practices. For low voltage cables, BS7671 must be followed. Due
to coastal location, materials resistant to corrosion should be selected for cable trays/cable racks.
01630.2.12
STEAM TURBINE GENERATOR BUS DUCT (GTA)
Function
The Steam Turbine Generator Bus Duct System provides a path for transfer of power from the steam
turbine generator terminal equipment to the generator transformer low voltage terminals and the static
excitation system transformer.
Major Components
The Steam Turbine Generator Bus Duct System will consist of the following major components:

Aluminum welded type isolated phase bus duct including straight pieces, fire wall
penetrations, bends, and phase transpositions.

Bus duct supports and hangers.

Tap bus to Static Excitation System Transformer

Connections to the Generator and Generator Step-Up Transformer and Generator surge
protection/potential transformer equipment.
System Description
Isolated phase bus will be used for the steam turbine generator bus duct.
The isolated phase bus duct will consist of individual aluminum rigidly supported conductors, housed in a
3-phase individual aluminum enclosure. The bus will be installed with rigid, nontracking, fire-resistant,
porcelain, and nonhygroscopic insulating supports capable of withstanding the mechanical forces of
short-circuit currents. The bus will be self-cooled, and provided with the following features:

Online temperature monitoring system that monitors temperature for all bolted connections.
The system shall include a local and remote alarm of bolted connection temperature.
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
Bus Duct air pressurization system. The air pressurization system shall prevent moisture and
dust ingress. The system shall monitor air consumption as a means of detecting sealing
system.

Air tight inspection doors are provided for access to all bolted connections and fitted close to
all sharp bends in the busbar system to provide adequate access for maintenance
requirements.
The Steam Turbine Generator Bus Duct System will be rated to continuously carry, as a minimum, 115%
of the Steam Turbine Generator maximum continuous current rating, and will be braced for the fault
current available. Temperature rise at the site altitude shall be limited as per SANS 60694:2003. The
bus duct insulation system shall maintain minimum insulation levels as per SANS 60694:2003 when filled
with atmospheric air at the site specific environmental conditions.
The Bus Duct System shall comply with the provisions of BS 159.
01630.2.13
COMBUSTION TURBINE GENERATOR CIRCUIT BREAKER (GTO)
Function
The Generator Circuit Breakers allow the generators to be synchronized to or disconnected from the
system. The Combustion Turbine Generator circuit breaker shall allow disconnection of the generator
from the system without power interruption to the Unit Auxiliary Transformer.
Major Components
The Generator Circuit Breaker consists of the following major components:

Indoor enclosure.

Self-cooled SF6 circuit breaker.

Non load break isolating switch.

Grounding switch – Generator side

Grounding switch – Transformer side

Control cabinet.

PT’s and CT’s
General Description
Generator Circuit Breakers shall be installed on two of the three combustion turbine generators, and they
shall be installed between the generator step-up transformer and the generator to provide a means for
synchronization or disconnection of the generator and the system, while maintaining power supply to the
Unit Auxiliary Transformer. The Generator Circuit Breakers shall be capable of full-load and fault current
interruption. The Generator Breakers shall provide motorized no-load break isolating switches on the
transformer side of the breaker.
Grounding switches shall be provided for the generator transformer side and the generator side of the
breaker. Grounding switches shall be capable of carrying the through fault current for the appropriate
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times with the resultant temperature rises limited. Grounding switches shall be suitable for the short circuit
current curve of the generator.
The design of the Generator Circuit Breaker System shall be rated to continuously carry 120% of the
Combustion Turbine Generator maximum continuous current rating, and shall be braced for the maximum
fault current available.
The Generator Circuit breaker shall comply with the provisions of IEC 62271-100.
01630.2.14
GENERATOR STEP-UP TRANSFORMER (GTU)
Function
The Generator Step-up Transformer provides the means to step up the generator terminal voltage to the
substation voltage for power transmission.
Major Components
The Generator Transformer System shall consist of the following major components:



One, three phase, two winding steam turbine generator step-up transformer.
Three, three phase, two winding combustion turbine generator step-up transformers.
Transformer rail system (furnish only – shared with the unit auxiliary transformer).
General Description
The generator step-up transformer shall transform electrical power received at generator voltage at its low
voltage terminals through the Steam Turbine Generator Bus Duct System and the Combustion Turbine
Generator Bus Duct System to the nominal transmission voltage of 400 kV.
Each generator step-up transformer shall be three phase, two winding oil-filled transformer furnished with
ODAF cooling rating and a 65C temperature rise. The transformer high voltage winding shall be
connected grounded wye. The transformer low voltage winding shall be delta connected. The
transformer shall be provided with an on-load tap changer. The transformer shall have sufficient capacity
to carry the maximum power output of each respective turbine across the site ambient temperature range.
Surge arresters shall be provided at the high voltage bushing to protect the transformer from surges on
the high voltage system resulting from lightning strikes or other system disturbances. Protective relays
shall detect and provide protection from internal and external faults, overheating, and overvoltage
conditions.
The transformer shall be provided with current transformers (CTs) as required.
Each transformer shall be set on a concrete pad. Oil containment basin shall be provided. Drainage
shall be routed to an oil/water separator. Firewalls shall be provided if required by NFPA 850.
The Generator Transformer System shall be designed to carry 10% greater than its respective generator
rated MVA.
The final selection of the electrical impedance for the Generator Transformer shall be coordinated with
the fault current ratings of the 400kV system, and the requirements of the South African Grid Code.
A transformer rail removal system, complete with permanent foundations, shall be furnished to allow
removal of any generator step-up transformer from its foundation and transport it to the location of any
other generator step up transformer. The rail removal system shall be designed to move the transformer
in a fully assembled state, without dismantling the transformer or draining the oil. The rail system shall be
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stored when not in use. The Contractor shall design and install permanent foundations for support of the
rail system.
The Contractor’s design shall not preclude moving transformers between the Coega 3x1 block and the
future Coega 3x1 block.
01630.2.15
COMBUSTION TURBINE GENERATOR BUS DUCT (GTK)
Function
The Combustion Turbine Generator Bus Duct Systems provide a path for transfer of power from the
combustion turbine generator terminals to the Generator Circuit Breaker, the Generator Step-up
Transformer low voltage terminals, the Unit Auxiliary Transformer, and the Static Excitation System
Transformer
Major Components
The Combustion Turbine Generator Bus Duct Systems shall consist of the following major components:

Aluminum welded type isolated phase bus duct including straight pieces, bends, phase
transpositions, and phase transpositions for each combustion turbine.

Bus duct supports and hangers.

Tap bus to Unit Auxiliary Transformer and Static Excitation System Transformer..

Connections to the Generator, Generator Circuit Breaker (where used), Static Excitation
System Transformer, Unit Auxiliary Transformer, and Generator Step-Up Transformer
General Description
Isolated phase bus shall be used for the Combustion Turbine generator bus duct.
The isolated phase bus duct shall consist of individual aluminum rigidly supported conductors, housed in
a three-phase individual aluminum enclosure. The bus shall be installed with rigid, nontracking, fireresistant, porcelain or epoxy resin, and nonhygroscopic insulating supports capable of withstanding the
mechanical forces of short-circuit currents. The bus will be self-cooled, and provided with the following
features:

Online temperature monitoring system that monitors temperature for all bolted connections.
The system shall include a local and remote alarm of bolted connection temperature.

Bus Duct air pressurization system. The air pressurization system shall prevent moisture and
dust ingress. The system shall monitor air consumption as a means of detecting sealing
system.

Air tight inspection doors are provided for access to all bolted connections and fitted close to
all sharp bends in the busbar system to provide adequate access for maintenance
requirements.
The Combustion Turbine Generator Bus Duct System shall be rated to continuously carry, as a minimum,
115% of the Combustion Turbine Generator maximum continuous current rating, and shall be braced for
the fault current available. Temperature rise at the site altitude shall be limited as per SANS
Source: 01630, 2005
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60694:2003. The bus duct insulation system shall maintain minimum insulation levels as per SANS
60694:2003 when filled with atmospheric air at the site specific environmental conditions.
The Bus Duct System shall comply with the provisions of BS 159.
01630.2.16
BUILDING LIGHTING (LTA)
Function
The Building Lighting System provides personnel with illumination for plant operations and control under
normal conditions, means of egress under emergency conditions, and emergency lighting to perform
certain manual operations during a power outage of the normal power source.
Major Components
The Building Lighting System shall consist of the following major components:



Light fixtures.
- Industrial fluorescent.
- Commercial fluorescent.
- Industrial emergency incandescent.
- High-pressure sodium.
Light switches.
Convenience receptacle socket outlets.
General Description
The Building Lighting System will consist mainly of switched industrial fluorescent fixtures for interior
industrial areas. Finished areas with suspended ceiling systems shall consist of commercial recessed
fluorescent troffers. Emergency incandescent lights shall be provided for interior egress lighting in the
event that the normal source of power for lights is lost.
High-pressure sodium light fixtures - suitable for wet locations - shall be provided outside and above
exterior door entrances, miscellaneous exterior platforms and process equipment areas. High pressure
sodium fixtures shall be provided for interior unheated locations, such as the turbine building, water
treatment building, and warehouse. Other areas, such as the fire pump building, hypochlorite generation
building, hydrogen generation building shall be lit with appropriate sources. Light sources used in
hazardous locations shall be listed for use in those locations. . High pressure sodium fixtures shall be
provided with E40 lamp sockets and powered from 230 volt, 50 Hz lighting panelboards.
Luminaires shall comply with the requirements of SANS 1464 and SANS 1119. Incandescent lights 200W
and below shall be of the clear type with E27 type lampholders.
The power supply for the building lighting system shall be from the normal AC power, essential services
AC power, or dc power system as required. The emergency lighting system shall be powered from the
essential services ac system; the luminaries shall be designed to burn at all times. The control room
lighting shall be fed from the essential services ac system and backed up by the dc system.
The bottom of convenience socket outlets in finished areas shall be installed 0.4 m above the floor in
areas that have suspended ceilings, and 1 m above the floor in areas that do not have ceiling systems.
The bottom of light switches shall be installed 1.2 m above the floor.
Convenience socket outlets in finished areas shall be 13 amp, 230 volt. Convenience socket outlets in
industrial areas shall be 16 amp, 230 volt, 3 pin type and shall be provided so a 25 metre extension cord
can access plant process equipment areas. All outdoor convenience outlets shall have IP56 or greater
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weather proof covers. Outdoor convenience socket outlets shall be derived from a 32 milliamp MCB
residual current circuit breaker.
The lighting system shall be designed to provide the required illumination levels in all areas and to meet
fire and safety codes. Illumination levels shall be in accordance with the recommendations of SANS 0114
Part 1 (Interior Lighting) and SANS 0114 Part 2 (Emergency Lighting).
01630.2.17
AREA LIGHTING (STH)
Function
The Area Lighting System provides illumination for the performance of general yard tasks, safety, and
Facility security.
Major Components
The Area Lighting System shall consist of the following major components:



High-pressure sodium luminaries.
Roadway lighting poles.
Interconnecting cable.
General Description
Illumination for roadways, parking areas, and other outdoor plant yard areas shall be provided by
photoelectric controlled high-pressure sodium luminaries. Where nearby structures for mounting the light
fixtures are not available, low maintenance galvanized steel anchor based lighting poles shall be
provided. Connections between area lighting poles shall be direct buried armoured cable circuits.
Power for the area lighting shall be 230/400 volt, 50 Hz provided by the AC Power Supply System.
Power for roadway or area lighting installed on poles shall be 230 volt, 50 Hz.
Area lighting shall be provided at the following locations:






Transformer area.
Circulating water intake structure.
Building entrances.
Paved roadways.
Parking areas.
Security fence installations.
The Area Lighting System shall be designed to provide the required illumination levels in site areas where
lighting is necessary for safety and tasks. Illumination levels shall be in accordance with SANS 10389-1
and SANS 10389-2. All cable connections for lighting shall be located within the lighting fixtures and
poles.
01630.3 Mechanical Systems
This section contains system descriptions for each of the major mechanical systems that will be
constructed as part of this Project. These system descriptions describe the function, major components,
and basis for design for each system.
The system descriptions contained within this section are as follows:


Station Air (CAA)
Control Air (CAB)
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

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















01630.3.1
WORKS INFORMATION
EMPLOYER REVIEW
20October06
Closed Cycle Cooling Water (ECB)
Fuel Gas Supply (FGA)
Fuel Oil Receiving and Supply (FOA)
Boiler Feed (FWA)
Condensate (FWC)
Condensate Polishing (FWD)
Cycle Makeup and Storage (FWF)
Condenser Air Extraction (HRB)
Circulating Water (HRC)
Heat Recovery Steam Generators (SGA)
Boiler Vents and Drains (SGF)
High Pressure Steam (SGG)
Low Pressure Steam (SGH)
Hot Reheat Steam (SGJ)
Cold Reheat Steam (SGK)
Steam Turbine Drains (SGL)
Steam Turbine Generator (TGA)
Combustion Turbine Generators (TGH)
Fire Protection Water Supply and Storage (WSE)
Station Air (CAA)
Function
The Station Air System supplies clean, dry air to nonessential users such as hose stations that require
compressed air for operating pneumatic tools for maintenance work.
Major Component
The Station Air System shall include the following major components:




Two full capacity, completely packaged, water cooled, electric motor driven, oil flooded, rotary
screw compressors, producing air at 125 psig (860 kPaG), complete with inlet air filters, oil/air
separation, after-cooling and air/water separation.
Two complete full capacity (to match compressor capacity) refrigerated air dryers, complete
with all controls and provisions for remote trouble annunciation.
One vertical, cylindrical, ASME Section VIII, Div. 1, air receiver, with relief valve and drain
trap.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Compressed air is supplied by one of two full capacity air compressors to the air receiver. Normally, one
compressor shall operate, loading and unloading to maintain the receiver pressure between 110 and 125
psig (760 and 860 kPaG). The second compressor shall be maintained in standby mode for immediate
startup in the event of trouble or trip of the operating compressor.
Compressed air from the receiver flows to the in-service air dryer, through the dryer’s inlet air filter, and
enters an air-to-air heat exchanger where it is precooled by the chilled outgoing air. The air then enters
the air-to-refrigerant heat exchanger and is cooled to the desired dew point. Air/water mixture enters the
separator and liquid water is removed from the air. An automatic drain discharges the collected
condensate from the system. The dry, chilled air enters the secondary side of the air-to-air exchanger to
reheat and help cool incoming compressed before exiting and then flows to the distribution system. The
compressed air is dried to a dew point of +40 oF (+4 oC). The distribution piping supplies dried, filtered
compressed air to quick disconnect hose connections distributed throughout the plant.
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Bypass lines shall be provided around the air receiver and air dryers.
Air drops from the main compressed air header to air users shall have a dirt leg and drain valve below the
lowest air user. The individual branch lines from the air drop to air users shall include an isolation valve
and flexible hose or tubing pig tail for connection to the final air user.
Station air shall be provided throughout the Turbine Building, Water Treatment Bldg, and around the
combustion turbine and HRSG, including hose stations on top of the HRSG at drum level.
All vent, drain, and air user connections shall be furnished with a single ball valve for isolation.
Materials of Construction
Materials of construction shall be as follows:





Air receiver – carbon steel ASME SA285, Gr. C, or ASME SA516 Gr. 70
Piping 2-1/2 inch (65 mm) and larger - carbon steel, A53 or A106, Gr. B, standard weight
Piping 2 inch (50 mm) and smaller – carbon steel, A53 or A106, Gr. B, schedule 80 fittings
Valves 2-1/2 inch (65 mm) and larger – Cast steel, ASTM A216 WCB, CL150, RF flanged
Valves 2 inch (50 mm) and smaller – Forged steel, ASTM A105, SWLD ends.
Controls and Instrumentation
The station air compressors and dryers are operated from local control panels on the compressors and
dryers. Running status and one trouble alarm for each compressor, and one trouble alarm for each dryer,
shall be monitored at the DCS operator interface stations. Compressed air system pressure at the air
receiver shall be monitored and displayed in the DCS. The DCS shall also have supervisory control
capability (start, stop, lead/lag selection).
Operating Requirements
In order to maintain both dryers in ready status, the plant operator must alternate use of the two full
capacity dryers on a weekly basis. This is a manual operation performed at the air dryers.
01630.3.2
Control Air (CAB)
Function
The Control Air System supplies clean, dry air to plant equipment that requires control air for operation,
and for pneumatic instruments and valves.
Major Components
The Control Air System shall include the following major components:
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Two full capacity, completely packaged, water cooled, electric motor driven, oil flooded, rotary
screw compressors, producing air at 125 psig (860 kPaG), complete with inlet air filters, oil/air
separation, after-cooling and air/water separation.
Two complete full capacity (to match compressor capacity) desiccant dryer units, each
including dual coalescing type prefilters, with automatic drains, for removal of moisture and
oil, a dual tower, heatless regeneration, desiccant air dryer, and dual particulate type
afterfilters for removal of desiccant particles, complete with all controls, humidity indicators
and provisions for remote trouble annunciation.
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One vertical, cylindrical, ASME Section VIII, Div. 1, air receiver, with relief valve and drain
trap.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Control air is supplied by one of two full capacity air compressors to the air receiver. Normally, one
compressor shall operate, loading and unloading to maintain the receiver pressure between at
approximately 110 and 125 psig (760 and 860 kPaG). The second compressor shall be maintained in
standby mode for immediate startup in the event of trouble or trip of the operating compressor.
Air from the receiver flows through the prefilters, to the active tower of the in desiccant air dryer, and is
dried to a dew point of -40 °F (-40 °C). A portion of the dried air is used to regenerate the desiccant in the
inactive tower of the in-service dryer and the remaining air passes through the afterfilters and flows to the
distribution system. The distribution piping supplies dried, filtered Control air to plant equipment requiring
air.
Bypass lines shall be provided around the air receiver and air dryers.
Air drops from the main Control air header to air users shall have a dirt leg and drain valve below the
lowest air user. The individual branch lines from the air drop to air users shall include an isolation valve
and flexible hose or tubing pig tail for connection to the final air user.
Control air shall be provided throughout the plant site, including the circulating water intake structure, as
required to serve all instrument air user requirements.
All vent, drain, and air user connections shall be furnished with a single ball valve for isolation.
Materials of Construction
Materials of construction shall be as follows:
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Air receiver – carbon steel ASME SA285, Gr. C, or ASME SA516 Gr. 70
Piping 2-1/2 inch (65 mm) and larger - ASTM A312 TP304 stainless steel, standard weight
Piping 2 inch (50 mm) and smaller – ASTM A312 TP304 stainless steel, schedule 80 SWLD
fittings
Valves 2-1/2 inch (65 mm) and larger – Cast stainless steel, ASTM A351 CF8M, CL150, RF
flanged
Valves 2 inch (50 mm) and smaller – Forged stainless steel, ASTM A182 F316, SWLD ends
Controls and Instrumentation
The control air compressors and dryers are operated from local control panels on the compressors and
dryers. Running status and one trouble alarm for each compressor, and one trouble alarm for each dryer,
shall be monitored at the DCS operator interface stations. Control air system pressure at the air receiver
shall be monitored and displayed in the DCS. The DCS shall also have supervisory control capability
(start, stop, lead/lag selection).
Operating Requirements
In order to maintain both dryers in ready status, the plant operator must alternate use of the two full
capacity dryers on a weekly basis. This is a manual operation performed at the air dryers.
Source: 01630, 2005
System Descriptions
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01630.3.3
WORKS INFORMATION
EMPLOYER REVIEW
20October06
Closed Cycle Cooling Water (ECB)
Function
The Closed Cycle Cooling Water System provides water for plant components and equipment that require
water cooling.
Typical cooling water users are:
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Steam turbine generator coolers
Steam turbine stator coolers
Steam turbine lube oil coolers
Steam turbine generator gas dryer
Combustion turbine generator coolers
Combustion turbine lube oil coolers
Combustion turbine generator gas dryer
Combustion turbine atomizing air coolers
Combustion turbine base cooling
Boiler feed pump lube oil and seal water coolers
Sample coolers and chiller units for secondary sample coolers
Air compressors
Major Components
The closed cycle cooling water system will include the following major components:
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Three 50 percent capacity, horizontal end suction, centrifugal pumps with electric motor
drives.
Two full capacity, shell and tube, closed cycle cooling water heat exchangers.
One atmospheric pressure, closed cycle cooling water expansion tank.
One chemical addition tank.
One suction strainer at the inlet of each closed cooling pump.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Two of three closed cycle cooling water pumps circulate closed cycle cooling water through one of two
closed cycle cooling water heat exchangers to the headers that distribute cooling water to the equipment
to be cooled. Cooling water return headers collect and return the cooling water to the suction of the
cooling water pumps.
The atmospheric pressure closed cooling water expansion tank is connected via piping to the pump
suction header and provides a reservoir of water to make up to the closed cooling water system as well
as providing storage capacity for the additional water volume of the system due to thermal expansion.
The tank shall be installed at an elevation above the highest point in the cooling water system. Makeup
water to the expansion tank is supplied from the Cycle Makeup and Storage System (FWF).
Sample connections and a chemical addition tank are provided for monitoring the condition of the
inhibitors in the closed cycle cooling water and for adding chemicals. The standard Employer treatment
for closed cooling water is trisodium phosphate conditioning plus tolytriazole (if copper alloys are
present).
Isolation valves are provided at the inlet and outlet of the closed cycle cooling water heat exchangers and
each of the components requiring cooling water. A sentinel or thermal relief valve shall be installed
between the cooled equipment and the outlet isolation valve to prevent overpressure due to thermal
Source: 01630, 2005
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expansion of liquid contained between closed isolation valves. Test/vent or test/drain valves shall be
provided between the isolation valves and the coolers.
All vent, drain, and instrument connections shall be furnished with a single valve for isolation.
Materials of Construction
Materials of Construction shall be as follows:
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Closed cycle cooling pumps – Cast or ductile iron casing, stainless steel shaft and shaft
sleeves, and cast steel impeller
Closed cycle cooling head tank – ASTM A285, Gr. C or ASTM A516 Gr. 70
Chemical addition tank – ASTM A285, Gr. C or ASTM A516 Gr. 70
Closed cycle cooling heat exchangers – Carbon steel shell with CSDS A52 or A66 coating
and impressed current cathodic protection provided for internal surfaces. Titanium tubes and
tube sheets.
Piping 2-1/2 inch (65 mm) and larger – ASTM A53 A106 Gr. B standard weight
Piping 2 inch (50 mm) and smaller – ASTM A53 A106 Gr. B Schedule 80
Valves 2 inch (50 mm) and smaller – Forged steel ASTM A105
Valves 2-1/2 inch (65 mm) and larger – Cast steel ASTM A216 WCB
Controls and Instrumentation
The Closed Cycle Cooling Water System is controlled through the DCS. The closed cycle cooling water
pumps are operated from the DCS operator interface stations in the control room. Normally two pumps
will be running and the third pump will be in “standby”. The standby pump shall start automatically, in the
event that the running pump trips or the system differential pressure is low.
The DCS shall monitor and indicate the closed cycle cooling water expansion tank level, pressure drop
across the strainer, and the closed cycle cooling water heat exchanger inlet and outlet water temperature
and pressure. Low water level in the expansion tank shall be alarmed.
01630.3.4
Fuel Gas Supply (FGA)
Function
The Fuel Gas Supply System receives gas from the LNG facility and delivers it to the equipment requiring
fuel gas. The fuel gas system heats, conditions, and delivers fuel gas to the combustion turbines as the
primary fuel. The delivery temperature of the gas shall meet the combustion turbine manufacturer’s
recommendations for minimum superheat above the gas hydrocarbon dew point temperature.
Major Components
The Fuel Gas Supply System shall include the following major components in the common fuel gas
supply line:
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One motor operated remote emergency shutoff valve near the site boundary
Two full capacity fuel gas filter separators in parallel installed upstream of the site fuel gas
pressure regulating and metering station.
Two full capacity site fuel gas pressure regulating and metering stations in parallel located
near the site boundary.
The Fuel Gas Supply System shall include the following major components for each combustion
turbine/HRSG unit:
Source: 01630, 2005
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One full capacity fuel gas filter/separator installed upstream of the fuel gas heaters.
One hot water heated fuel gas heater to raise the temperature of the fuel delivered to the
combustion turbine to 365F, or other temperature as required by the CTG manufacturer, for
cycle performance enhancement and emissions control.
One electric start-up fuel gas heater.
One full capacity fuel gas scrubber installed immediately downstream of the fuel gas heaters.
One atmospheric pressure drain tank to collect drains from the fuel gas filter/separator, startup heater, and fuel gas scrubber.
One fuel gas flow meter, supplied by the combustion turbine manufacturer, for installation in
the fuel gas piping downstream of the fuel gas scrubber.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Natural gas is delivered from an offsite pipeline to the site metering and pressure regulation station.
Custody of the gas is transferred at the fence, or at the outlet of the last valve, of the regulating and
metering station.
If the gas supplied does not meet the combustion turbine manufacturer’s recommendations for superheat
above the hydrocarbon fuel dew point, additional heating shall be provided. Because hot water for the
fuel gas heater is not available during startup, a startup fuel gas heater shall be provided to heat the gas
to the turbine manufacturer’s recommended minimum superheat temperature.
Fuel gas to the combustion turbine flows through a filter/separator, fuel gas heater, a fuel gas scrubber,
and a gas flow meter assembly to the gas supply connection at the CTG. Piping downstream of the
scrubber shall be stainless steel.
Drains from the fuel gas filter/separators, heaters, and scrubbers shall be directed to a dedicated drain
tank. The drain tank shall vent to atmosphere and have a connection for periodic removal of the liquids
collected.
The fuel gas heaters, the filter/separators, fuel gas scrubbers, the filter/separator drain tanks, and related
flanged connections must be located in an area defined as hazardous because of the potential for
discharge of fuel gas. All electrical devices and instrumentation located within these areas shall be rated
in accordance with Section 01400 and the specific equipment technical specifications herein..
The fuel gas piping shall include provisions for cleaning by blowing with fuel gas or compressed air.
These provisions shall include a flanged section of piping to be left out of the fuel gas line to each
combustion turbine and a temporary pipe spool for directing the fuel gas or air blow to a safe location.
A remote operated emergency fuel shutoff valve shall be provided at the site interface point to allow the
control room to shut off the fuel gas supply in case of an emergency.
All miscellaneous vent, drain, and instrument connections shall be furnished with a single ball valve for
isolation.
Materials of Construction
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Fuel gas filter separators – ASME SA285, Gr. C or SA516-70
Fuel gas scrubbers – ASME SA285, Gr. C or SA516-70
Fuel gas filter separator/scrubber drain tanks – ASTM A285, Gr. C or A516-70 (atmospheric
– non-ASME code)
Fuel gas heaters – Carbon steel shell and tubes
Source: 01630, 2005
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Piping – ASTM A53 or A106 Gr. B, upstream of the final fuel gas filter separator, and ASTM
A312, TP304, downstream of the final fuel gas filter separator. Weld code W1 shall be used
for carbon steel piping upstream of the fuel gas separator and for stainless steel piping
between the fuel gas scrubber and the combustion turbine.
Valves 2 inch (50 mm) and smaller – CL600, socket weld, forged steel ASTM A105 for
carbon steel piping and ASTM A182 TP304 for stainless steel piping.
Valves 2-1/2 inch (65 mm) and larger – CL300 and CL600, buttwelded, flanged, wafer, or lug,
cast steel ASTM A216 WCB for carbon steel piping and ASTM A351 Gr. CF3 for stainless
steel piping.
Note: All valves shall be suitably rated for fuel gas service (Factory Mutual or otherwise
approved).
Controls and Instrumentation
The fuel gas regulating and metering station will be monitored and controlled by the fuel gas supplier.
Flows, pressures and temperatures are transmitted to the DCS.
The fuel gas system shall be monitored and controlled by the DCS. A fuel gas flow meter shall be
provided in each line to the combustion turbines. Individual combustion turbine gas consumption rates
shall be monitored by the DCS.
Fuel through the gas heaters shall be monitored and temperature controlled by the DCS. Fuel gas is
typically heated with IP economizer outlet water. Gas temperatures are controlled by regulating the flow
of water to the heaters.
Liquid-side to gas-side leakage in the fuel gas heaters shall be monitored by level switches in the
downstream filter/separator and shall be alarmed in the DCS. The levels in the fuel gas filter separators
and scrubbers are monitored and controlled locally by level switches and a drain control valve. The highhigh level switch shall be monitored and alarmed in the DCS.
Leakage from the gas side to the liquid side in the heaters shall be monitored by level switches in a tube
leak detection column located in the water piping downstream of the fuel gas heaters. Detection in the
column causes waterside isolation and an alarm in the DCS. Other approaches to leak detection shall
also be considered.
If hydro testing with water is performed, the system shall have low point drain capability and the piping
shall be drained and thoroughly dried immediately after hydrotesting is complete. Temporary spools are
required for flow element replacement during gas/air blow.
01630.3.5
Fuel Oil Receiving and Supply (FOA)
Function
The Fuel Oil Receiving and Supply System receives diesel from off-site storage tanks, stores it in the Fuel
Oil Storage Tank, and delivers fuel oil to the combustion turbines as a secondary fuel.
Major Components
The Fuel Oil Receiving and Supply System shall include the following major components:

One vertical, steel, column supported, cone roof, field erected Fuel Oil Storage Tank. The
tank shall be sized for 24 hours of base load operation of three combustion turbines on fuel
oil. Space shall be provided for a future second tank of similar size. Either a cathodic
protection system shall be provided for the tank bottom exterior surfaces in contact with soil
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or a concrete seal slab shall be placed under the tank to isolate the tank bottom from the soil.
Containment shall be provided around the fuel oil tanks large enough to contain 110% of the
tank storage capacity.
Two horizontal, end suction, electric motor driven full capacity fuel truck unloading pumps.
Three fuel forwarding pump skids, each with two full capacity (equal to 100 percent flow for
one combustion turbine plus continuous recirculation flow), horizontal, end suction, electric
motor driven, fuel oil forwarding pumps.
Two full capacity, horizontal, end suction, electric motor driven, fuel transfer pump shall
provide fuel oil to the auxiliary boiler, black start diesel generator, and diesel driven fire pump.
A basket strainer shall be provided on the suction of each pump.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Fuel oil is normally received from off-site storage tanks (by others) but may also be delivered by truck
through the fuel truck unloading station. Containment shall be provided around truck unloading stations
and fuel oil unloading pumps in accordance with Employer's regulations. Interface for the fuel oil supply
pipe from off-site storage tanks shall be at the fence line. An automatic tank level control valve shall be
provided that is coordinated with the off-site fuel supply system.
The fuel oil storage tank shall be of double wall construction with foam connections on the fuel oil tank for
fire protection foam system. The tank shall have valved connections with blind flanges to allow addition of
the future storage tank and pumps. The fuel forwarding skids shall take fuel oil directly from the fuel oil
storage tank suction.
A flow orifice and transmitter are required in the fuel line to each combustion turbine to provide a fuel oil
flow signal to the DCS. This flow signal may be re-transmitted from the DCS to the CEMS equipment for
emissions calculations. Separate flow meters shall be provided to record fuel flow to the aux boiler and
diesel generator, individually.
During operation of the combustion turbines on fuel oil, one fuel oil forwarding pump for each forwarding
skid shall be in service for each combustion turbine operating on fuel oil.
The fuel oil forwarding pump suction pipe shall be routed flat or sloped down to the pumps. All piping
shall be routed aboveground or in trenches. Routing of oil piping underground shall be avoided because
of requirements for double containment. Road crossings shall be made in trenches and all other oil lines
shall be routed on sleepers or in the pipe rack so they are available for visual inspection. Separate
2x100% fuel oil forwarding pumps shall be furnished to feed the diesel engine day tanks and the auxiliary
boiler fuel system. Both the diesel engine and the auxiliary boiler shall be furnished with separate supply
pumps to directly feed the equipment.
All vent, drain, and instrument connections shall be furnished with a globe valve for isolation.
Materials of Construction
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Fuel oil storage tank – ASTM A36, ASTM A283 Gr. C, or ASTM A285, Gr. C, as limited by
API-650.
Fuel oil pumps – Ductile iron or cast steel casing, stainless steel shaft and shaft sleeves, and
cast steel impeller.
Piping – Carbon steel ASTM A53 or A106 Gr. B
Valves 2 inch (50 mm) and smaller – CL 600, socket weld, forged steel ASTM A105
Valves 2-1/2 inch (65 mm) and larger – CL150, flanged, cast steel ASTM A216 WCB
Controls and Instrumentation
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Control of the fuel oil receiving and supply system is provided through local controls and remotely through
the DCS operator interface stations in the control room. The operators shall start a fuel oil forwarding
pump prior to starting a gas turbine on fuel oil or before transferring the gas turbine fuel supply from gas
to oil. Controls shall also be provided for the fuel oil forwarding pumps feeding the auxiliary boiler and the
diesel generator day tanks.
Alarms and automatic shutdowns shall be annunciated in the control room and displayed on the DCS
operator interface stations.
Level indication for the fuel oil storage tank is displayed on the DCS operator interface station and locally
at the tank by means of a level indicator (float and gage board type indicator). Differential pressure
across the transfer pump duplex strainer is monitored by a differential pressure transmitter and alarmed in
the DCS when the strainer needs cleaning. The fuel oil forwarding pump discharge header pressure is
monitored and displayed in the DCS.
Fuel oil flows to the combustion turbines are monitored in the DCS and may be transmitted to the CEMS
for use in emission calculations.
01630.3.6
Boiler Feed (FWA)
Function
The Boiler Feed System provides water from the deaerator to the high-pressure, intermediate-pressure,
and low pressure economizers of the Heat Recovery Steam Generators (HRSG). The Boiler Feed System
also supplies water for the HP steam desuperheater(s) and HP steam bypass desuperheater(s), and
reheat steam desuperheater(s).
Major Components
The boiler feed system shall include the following major components for each Heat Recovery Steam
Generator:
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Two 100% capacity, segmental ring, multi-stage, variable speed, motor driven, IP/HP
feedwater pumps. Each pump shall have an inter-stage bleed-off for intermediate-pressure
feedwater. The pumps shall include a pressurized lube oil system, lube oil coolers,
mechanical seals, hydraulic coupling or variable frequency drive as determined by the
Employer, and seal water coolers.
Two 100% capacity, segmental ring, multi-stage, variable speed, motor driven, LP feedwater
pumps. Consideration will be given to other pump types depending on the expected
deaerator and LP drum operating pressures. The pumps shall include a pressurized lube oil
system, lube oil coolers, mechanical seals, and seal water coolers. The pumps will be electric
motor driven by either direct coupling, speed increaser, hydraulic coupling or variable
frequency drive as determined by the Employer.
A modulating recirculation control system for each feedwater pump to ensure minimum pump
flow.
Flow elements, one per pump discharge for flow measurement and recirculation control, one
each for the economizer feedwater flows for use in three element drum level control, one
each for HP and reheat attemperation spray flows, and one for HP steam bypass spray flow.
Each boiler feedwater pump shall have a duplex suction basket strainer with differential
pressure transmitter for monitoring and alarming. Drain and vent connections on these
strainers shall be the largest standard sizes available.
Interconnecting piping, valves, instrumentation, and accessories.
For pumps with top suction and discharge connections, flanged spool pieces shall be provided to facilitate
pump dismantling for maintenance and chemical cleaning.
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General Description
Two boiler feedwater pumps per HRSG shall supply HP and IP feedwater at the pressure necessary to
overcome static and friction losses and provide the pressure required at the economizer inlets. The
pumps shall be sized to supply feedwater to the HP drum at 3 percent above the highest safety valve set
point. One full range HP feedwater control valve shall be provided for controlling HP drum level. One full
range feedwater control valve shall be provided for controlling IP drum level. The feedwater regulators
shall automatically control the feedwater flow rates to match the steam flows and maintain steam drum
levels.
Two boiler feedwater pumps per HRSG shall supply LP feedwater at the pressure necessary to overcome
static and friction losses and provide the pressure required at the economizer inlet. The pumps shall be
sized to supply feedwater to the LP drum at 3 percent above the highest safety valve set point. One full
range LP feedwater control valve shall be provided for controlling LP drum level. The feedwater
regulators shall automatically control the feedwater flow rates to match the steam flow and maintain
steam drum level.
Desuperheating spray water shall be provided to several users. HP steam desuperheater and HP steam
bypass desuperheater water shall be provided from the HP feedwater pump discharge. Hot reheat steam
attemperation shall be provided with spray water from the IP feedwater discharge.
Each boiler feed pump shall be provided with a recirculation line back to the deaerator storage tank
containing a modulating control valve sized to maintain the minimum pump flow rate as specified by the
pump manufacturer.
The boiler feedwater system shall be filled from the condensate system. Connections from the
Condensate System shall be provided on the feedwater piping to supply water for filling the economizers
and drums.
The boiler feed system shall be designed in accordance with ASME B31.1, Power Piping.
All vent, drain, and instrument connections exposed to pump discharge pressures shall be furnished with
double gate or globe valves for isolation.
Materials of Construction
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Feedwater pumps – Cast 1-1/4 chrome steel casing, 12 percent chrome steel shaft, impellers
and wear rings
Feedwater pump duplex suction strainers – cast iron or carbon steel body with stainless steel
baskets
Piping – ASTM A53 or A106 Gr. B or C (seamless for discharge piping)
HP Boiler Feedwater Valves 2 inch (50 mm) and smaller – forged steel ASTM A105, socket
weld
HP Boiler Feedwater Valves 2-1/2 inch (65 mm) and larger – cast steel ASTM A216 WCB or
WCC
IP Boiler Feedwater Valves 2 inch (50 mm) and smaller – forged steel, ASTM A105, socket
weld
IP Boiler Feedwater Valves 2-1/2 inch (65 mm) and larger – cast steel ASTM A216 WCB or
WCC
LP Boiler Feedwater Valves 2 inch (50 mm) and smaller – forged steel, ASTM A105, socket
weld
LP Boiler Feedwater Valves 2-1/2 inch (65 mm) and larger – cast steel ASTM A216 WCB or
WCC
Welding codes – W1, W2 (refer to Section 01400, Supplemental Q210 for definition)
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Controls and Instrumentation
The feedwater system shall be controlled and monitored through the plant DCS. The boiler feed pumps
shall be started, stopped and monitored from the DCS operator interface stations. The boiler feedwater
pumps shall be tripped on low level in the deaerator.
A flow element shall be provided for each IP/HP boiler feed pump to measure pump HP discharge flow
upstream of the minimum flow recirculation line to the deaerator. This flow element shall be used to
control the recirculation valve.
A flow element shall be provided for each LP boiler feed pump to measure pump LP discharge flow
upstream of the minimum flow recirculation line to the deaerator. This flow element shall be used to
control the recirculation valve.
A flow element shall be provided in the common HP discharge line to measure total flow to the HP
economizer. This flow signal shall be used in the three element level control scheme for the HP drum,
which is used to control the HP feedwater drum level control valves.
A flow element shall also be provided in the common IP discharge line to measure total flow to the IP
economizer. This flow signal shall be used in the three element level control scheme for the IP drum
which shall be used to control the IP feedwater drum level control valve. On units where the IP
economizer supplies water for fuel gas heating, this flow element shall be located between the
economizer and the IP drum downstream of the branch to the fuel gas heater.
A flow element shall be provided in the common LP discharge line to measure total flow to the LP
economizer. This flow signal shall be used in the three element level control scheme for the LP drum,
which is used to control the LP feedwater drum level control valves.
A flow element shall be provided in the HP steam bypass spray line for developing the calibration of the
HP spray valve flow used in the HP bypass spray control logic. A flow element shall also be provided in
the reheat steam attemperation spray line.
Boiler feedwater pressures shall be monitored upstream and downstream of the boiler feed pumps.
Feedwater temperatures shall be monitored in the common suction discharge piping. Boiler feedwater
pump suction strainers shall be monitored by differential pressure transmitters. Alarms shall be indicated
on the DCS operator interface stations.
01630.3.7
Condensate (FWC)
Function
The Condensate System receives and condenses steam from the steam turbine exhaust and
miscellaneous drains, and returns the condensate to the deaerator (s). The Condensate System also
supplies water for desuperheating hot reheat bypass steam, LP bypass steam (if required), turbine gland
seal steam (if required), reverse flow steam (if required), turbine exhaust hood spray, condenser curtain/
neck sprays, and miscellaneous steam drains to the condenser (if required). Condensate that must be
dumped due to system upset conditions or high hotwell levels shall be returned to the Condensate
Storage Tank for reuse. Further information on the operation of this tank is provided in the description of
the Cycle Makeup and Storage System (FWF).
Major Components
The condensate system shall include the following major components:
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One full capacity, two shell condenser with double water pass design and divided water
boxes arranged to allow two separate cooling water paths. The condenser hot well shall be
sized to hold a minimum of 5 minutes supply of condensate. Corrosion control provisions
shall be provided for water box surfaces wetted by circulating water.
Three 50 percent capacity, multistage, vertical can type condensate pumps with discharge
connections above the floor level. The condensate pumps shall be direct coupled to, and
driven by, vertical electrical motors with Kingsbury type thrust bearings mounted at the top of
the motors and a radial bearing at the drive end of the motor.
A minimum flow recirculation control system to ensure minimum flow requirements for the
pumps and the turbine gland steam condenser.
Eight flow elements, one orifice plate for minimum flow control located in the pump
recirculation line, one flow nozzle per deaerator for level control, one orifice plate per HRSG
for hot reheat bypass desuperheater control and special calibrated flow nozzle test sections
shall be furnished for performance testing. The calibrated flow nozzle test sections are
required for overall plant performance testing. They are temporarily installed in place of each
deaerator flow element when performance testing is conducted. Only the main flow nozzles
to each HRSG (see FWC P&ID Sht E) get replaced like this during performance testing.
Additionally, one orifice plate shall be provided per HRSG for LP steam bypass
desuperheater control (if required).
A basket strainer with differential pressure monitoring instrumentation at the suction of each
condensate pump. The basket strainer shall have a full lift out basket. Tee type strainers shall
not be used.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The condensate pumps shall take suction from the condenser hotwell and discharge to the condensate
distribution system. The condensate shall flow from the pumps through the recirculation control flow
orifice, through the steam turbine gland steam condenser, and then split into three lines to the deaerators
and three lines to the HRSG hot reheat bypass sprays. The minimum flow recirculation line shall branch
off the main header downstream of the minimum flow control orifice and return the recirculated
condensate to a connection above the condenser tubes. In each of the individual lines to the deaerators,
there shall be a condensate flow control valve and a flow element to provide the condensate flow signal
for the deaerator level control.
The condensate level in the hotwell shall be monitored and controlled by the addition of makeup water
from the Cycle Makeup and Storage System or by dumping of condensate to the condensate storage
tank. The demineralized makeup water shall be admitted to the condenser shell above the tube bundles
and is cascaded down through the tube bundle to deaerate the makeup water. The condensate dump
line shall branch off the main condensate header downstream of the minimum flow recirculation line.
The condensate system shall supply water for desuperheating the hot reheat steam bypass to the
condenser, desuperheating LP steam bypass (if required), desuperheating gland seal steam (if required),
desuperheating miscellaneous drains discharged to the condenser (if required), supplying turbine exhaust
hood spray water, or for supplying water to condenser neck sprays for overtemperature protection during
steam bypass operation and reverse flow (if required).
Chemical addition connections shall be provided for the addition of chemicals from the Cycle Chemical
Feed System (FWE). Water sample connections upstream and downstream of the chemical addition
points shall be provided for the Sampling and Analysis System (SAC).
The condensate system shall be designed in accordance with ASME B31.1.
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All miscellaneous vent, drain, and instrument connections shall be furnished with a single ball, gate, or
globe valve for isolation.
Materials of Construction
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Condensate pumps – carbon steel column, cast iron bowls, carbon bearings, stainless steel
shaft, stainless steel first stage impeller and stainless steel wear rings
Condensate pump suction strainers – Carbon steel or cast iron body with stainless steel
basket
Orifice plates – ASTM 240 Gr. 304 stainless steel
Piping – ASTM A53 or A106 Gr. B
Valves 2 inch (50 mm) and smaller – forged steel ASTM A105, socket weld
Valves 2-1/2 inch (65 mm) and larger – cast steel ASTM A216 WCB, flanged
Weld codes – W1, W2 (refer to Section 01400, Supplemental Q210 for definition)
Controls and Instrumentation
The Condensate System shall be controlled through the DCS. Normally, the two 50 percent capacity
condensate pumps will be started manually from the DCS operator interface stations and the third pump
will be in standby mode to start automatically in the event of a trip of the running pump or during full
steam bypass with three Combustion Turbines online.
The condenser level shall be monitored by redundant level transmitters. A makeup control valve shall
add water on low level and a dump control valve dumps water to the condensate storage tank on high
level. The condensate pumps shall be tripped on low-low condenser level.
A flow element shall be installed in the condensate header upstream of the steam turbine gland steam
condenser (and steam jet air ejector condenser, if applicable) to measure condensate pump discharge
header flow. This flow element shall be used to control the minimum flow recirculation valve to ensure
that adequate flow is maintained through the pump and gland steam condenser.
A flow element shall be provided in each deaerator line to measure flow to the deaerator. This flow signal
shall be used to control deaerator level and condensate pump minimum flow.
Condensate system temperatures and pressure shall be monitored and displayed on the DCS operator
interface stations. A flow element is provided in each of the Hot Reheat steam bypass spray lines for
developing the calibration of the RH spray valve flows used in the bypass spray control logic.
Condensate pump suction strainers shall be monitored by differential pressure transmitters and alarms
shall be indicated on the DCS operator interface stations. Each condensate pump discharge pressure
shall be locally indicated.
Condenser absolute pressure shall be monitored by redundant pressure transmitters to generate
condenser protective logic for permitting and tripping the steam bypass systems discharging into the
condenser.
01630.3.8
Condensate Polishing System (FWD)
Function
The function of the Condensate Polishing System is to remove contaminates from the condensate and to
maintain the quality of the feedwater in the cycle.
Major Components
The Condensate Polisher System shall include the following major equipment and components:
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Three half capacity Cation Ion Exchange Vessels
Three half capacity Mixed Bed Ion Exchange Vessels
Two full capacity recycle pumps
Resin Hopper
Cation Bed Regeneration Tank
Mixed Bed Cation Regeneration Tank
Mixed Bed Anion Regeneration Tank
Mixed Resin Storage Tank
Cation Resin Storage Tank
Condensate Polisher Water Heater
Acid Feed and Dilution Skid with local control box, dilution tank, eductor and specific
conductivity analyzer
Caustic Dilution Skid with local control box, dilution tank, eductor and specific conductivity
analyzer.
Caustic Storage Tank
Acid Storage Tank with vent dryer
All necessary piping, valves, and instrumentation required for operating the system.
General Description
Effluent from the condensate pumps is split between three Ion Exchange trains. Each train contains a
cation and mixed bed exchanger. The cation exchanger filter any solids and acts as a guard for the
trailing mixed beds by removing ammonia and prevents premature exhaustion of the mixed beds. The
mixed bed exchangers contain both anion and cation exchange resins that remove dissolved impurities
from the condensate. Typically, two polishing trains are in service while the third is placed in standby or is
undergoing regeneration.
Samples shall be taken from the effluent of each cation and mixed bed in service. These samples shall be
routed to the sample panel (SAC). The samples shall be tested to determine the quality of water being
discharged. The results of these analyses shall determine when a specific polisher vessel should be
taken off line and regenerated.
During regeneration, the ion exchange resin is transferred from the ion exchange bed to the cation
regeneration tank. Here the resin is cleaned and separated into cation and anion fractions (if applicable).
The anion fraction is routed to the anion regeneration vessel. Here the anion resin is treated with caustic
while the cation resin is treated with acid. Both resins are then rinsed with demineralized water. The
resins are combined (if applicable) in the resin storage tank for transfer back to the ion exchange vessel.
Alternative regeneration system designs will be considered for installation depending upon the selected
suppliers proprietary design practices. The resin transfer system shall guarantee a minimum 99.9%
transfer efficiency (i.e. ≥99.9% resin removal from any given vessel- service/separation/ regeneration/
storage).
Materials of Construction
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Ion Exchange Vessels (cation and mixed bed) –304 or 316 stainless steel
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Regeneration Vessels and Resin Storage Vessels –lined carbon steel
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Condensate Polisher Recycle Pumps – Stainless Steel
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Condensate piping, vent, and drain piping – Carbon steel
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Resin Transfer piping – PPL lined
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All wetted components not listed above shall be provided according to the following services:
Concentrated Acid- Alloy 20
Dilute Acid- PPL Lined
Concentrated Caustic- Carbon Steel
Dilute Caustic- Stainless Steel
Condensate- Carbon Steel
Controls and Instrumentation
Control of the system shall be via local PLC with supervisory control and monitoring from the DCS
Instruments and analyzers shall be used to monitor and manage the operation of the condensate
polishers and associated equipment. These instruments include differential pressure transmitters, flow
transmitters, pressure switches, level switches, pressure indicators, temperature indicators, temperature
switches and temperature transmitters. The system shall also be provided with conductivity analyzers.
01630.3.9
Cycle Makeup and Storage (FWF)
Function
The Cycle Makeup and Storage System receives demineralized water from the Cycle Makeup Treatment
System (WTD) and stores it in the Demineralized Water Storage Tank. The demineralized water is
distributed for the following uses:
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Steam cycle emergency makeup water to the condenser to replace
condensate/feedwater/steam lost to leakage, drains and boiler blowdown.
Injection water to the combustion turbines for NO x emissions control when firing liquid fuel.
Combustion turbine wash water.
Condensate polisher regeneration supply.
Condensate system fill.
Dilution water to the cycle chemical feed system (may be supplied from FWC instead).
In addition, the Cycle Makeup and Storage System receives condensate from the condensate dump
system and stores it in the Condensate Storage Tank. This water is subsequently reused in the cycle to
help minimize the consumption of cycle treatment chemicals. Cycle users include the following:
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Steam cycle normal makeup water to the condenser to replace condensate/feedwater/steam
lost to leakage, drains and boiler blowdown.
Condensate pump seal water.
Makeup water to the closed cycle cooling expansion tank.
Major Components
The Cycle Makeup and Storage System shall include the following major components:
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One vertical, welded steel, self supporting dome or cone roof, field erected Demineralized
Water Storage Tanks. One current tank and space for one future tank of like design to
service the second 3x1 CC block shall be provided. The tanks shall be coated internally with
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an epoxy coating system suitable for immersion in high purity water. The tanks shall be
equipped with a vent and air filter and piping inlet, outlet, overflow, drain, instrument
connections, and corrosion control prevention for exterior tank bottom plates. All connections
internal piping appurtences shall be stainless steel. Each tank shall be sized for supporting
three combustion turbines at full load on diesel fuel for 24 hours based upon a water injection
to diesel fuel consumption ratio of not less than 1.3.
Two full capacity, horizontal, end suction, electric motor driven, demineralized water transfer
pumps. The demineralized water pumps shall be of stainless steel construction. The pumps
shall have recirculation lines back to the demineralized water tank, with flow control orifices,
to provide minimum flow protection for the pumps.
One vertical, welded steel, self supporting dome or cone roof, field erected Condensate
Storage Tank. One current tank and space for one future tank of like design to serve the
second 3x1 CC block shall be provided. The tank shall be equipped with a vent and air filter
and piping inlet, outlet, overflow, drain, instrument connections, and corrosion control
prevention for exterior tank bottom plates. The Condensate Storage Tank shall have a
useable capacity of 946,000 litres.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The Cycle Makeup and Storage System consists of two demineralized water storage tanks, one
condensate storage tank, and two demineralized water transfer pumps, associated piping, valves and
instrumentation.
Demineralized water is supplied to the demineralized water storage tanks through an aboveground line
from the Cycle Makeup Treatment System in the Water Treatment building. All piping and valves shall be
stainless steel.
The condensate storage tank shall be filled by the high level dump valve in the condensate system.
Normally, water shall be supplied to the condenser by “vacuum drag” from the condensate storage tank.
The static head of water in the storage tank combined with the vacuum in the condenser shall provide the
motive force to supply makeup water to the condenser. In cases when the water level in the condensate
storage tank is too low to support “vacuum drag”, the transfer pumps may be used to provide normal
makeup to the condenser hotwell. The transfer pump shall also be operated if makeup is required to the
elevated closed cycle cooling water head tank.
When the combustion turbines are operating on fuel oil and demineralized water injection is required for
NOx control, one of the two demineralized water transfer pumps shall operate to provide demineralized
water to the suction side of the CTG water injection systems.
Water sample connection(s) shall be provided for the Sampling and Analysis System (SAC) to monitor
makeup water quality.
All miscellaneous vent, drain, and instrument connections shall be furnished with a single ball or globe
valve for isolation.
Materials of Construction
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Demineralized water storage tank – Carbon steel coated in accordance with Technical
Specification 13202
Condensate storage tank – Carbon steel coated in accordance with Technical Specification
13202
Demineralized water transfer pumps – All wetted parts of stainless steel construction.
Piping – ASTM A312 TP304 stainless steel.
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Valves 2 inch (50 mm) and smaller – CL 600, forged steel ASTM A182 F316, socket weld
Valves 2-1/2 inch (65 mm) and larger – CL 150, cast steel ASTM A351 Grade CF8 or CF8M,
flanged or welded
Piping that can only contain condensate may be carbon steel. Valves in this piping may be
carbon steel or cast/ductile iron.
Controls and Instrumentation
The demineralized water pumps shall be controlled from the DCS operator stations. When required, one
pump shall be started in manual mode, and the other shall be in standby mode to automatically start in
the event that the running pump trips or header pressure becomes low.
Level transmitters on the demineralized water storage tank and the condensate storage tank monitor level
in the tanks and the levels shall be displayed on the DCS operator interface stations. The tank level
signals shall also be used for control in the Cycle Makeup Water Treatment System (WTD), provide high
and low level alarms, and interlock pump operation.
A pressure transmitter monitors the demineralized water transfer pump discharge header, the pressure is
displayed on the DCS operator interface stations, and is used for start of the standby pump if one pump is
running and header pressure is low. Pressure shall be monitored on each demineralized water transfer
pump suction or discharge.
01630.3.10
Condenser Air Extraction (HRB)
Function
The Condenser Air Extraction System removes the noncondensable gases from the cycle during steam
turbine generator operation, rapidly reduces the condenser pressure before unit startup, and vents the
condenser steam space after turbine trips.
Major Components
The Condenser Air Extraction System shall consist of two identical equipment skids. Each skid shall
include the following major components:
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One full capacity two stage condensing steam jet air ejector assembly designed for holding
operation.
One full capacity condenser exhauster vacuum pump designed for hogging operation,
including:
o Vacuum pump.
o Separator tank.
o Seal water cooler.
o Seal water recirculation pump.
Piping, valves, controls, and instrumentation necessary for proper system operation.
General Description
The Condenser Air Extraction System shall consist of two identical equipment skids. Each skid shall
contain one two stage dual element steam jet air ejector package designed for holding operation, a
separate electric motor driven hogging vacuum pump assembly, and the interconnecting piping between
the condenser and the air ejector package.
Each dual element steam jet air ejector package shall consist of two 100% first stage air ejectors, two
100% second stage air ejectors, one 200% capacity intercondenser, one 200% aftercondenser, and
associated piping and valves. Each hogging vacuum pump assembly shall consist of one large capacity
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vacuum pump discharging to atmosphere through a separator and silencer. A motor operated condenser
vacuum breaker valve shall be located on the condenser shell. This valve shall be sized in accordance
with the steam turbine manufacturer’s requirements.
The hogging system must be able to draw the condenser pressure down from atmospheric to 10 inches
HgA in not more than 15 minutes.
The vacuum pump shall compress the non-condensable gases and discharge the gases to a separator at
a pressure slightly above that of atmospheric pressure. Any entrained moisture discharged from the
condenser vacuum pump shall be collected in the separator and reused as seal water or sent to drain.
The dry non-condensable gases shall be vented to atmosphere through a silencer.
Materials of Construction
Materials of construction for the Condenser Air Extraction System shall be as follows:
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Piping – ASTM A312 TP304 stainless steel.
Valves 2 inch (50 mm) and smaller – Forged steel ASTM A182 F316, socket weld.
Valves 2-1/2 inch (65 mm) and larger – CL 150, cast steel ASTM A351 Grade CF8 or CF8M,
flanged or welded.
Welding codes – W1, W2
Controls and Instrumentation
The condenser air extraction system shall have two operating modes: hogging and holding. During
startup, the vacuum pump shall be used to evacuate the air from the condenser and rapidly reduce the
condenser pressure. The hogging process is done to allow admission of steam to the condenser in as
short a time as possible. Holding is the normal operating mode when the pressure in the condenser is
maintained below atmospheric pressure.
During the holding mode when auxiliary steam is available, the steam jet air ejector package shall remove
non-condensable gases from the steam spaces of the condenser.
The Condenser Air Extraction System shall be controlled through the DCS.
01630.3.11
Circulating Water (HRC)
Function
The circulating water system provides cooling water to the steam turbine condenser for condensing the
turbine exhaust steam and provides cooling water to the closed cycle cooling water heat exchangers.
The circulating water system rejects the steam turbine exhaust heat energy, and steam turbine bypass
system heat energy, and heat from auxiliary loads by way of a once through cooling system using sea
water.
Major Components
The circulating water system shall include the following major components:
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One intake structure.
One effluent channel.
Two 50 percent capacity, vertical, mixed flow, electric motor driven circulating water pumps
with discharge connections above the floor level.
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One motor operated butterfly valve on the discharge of each circulating water pump and
auxiliary cooling water pump.
One full capacity, vertical, electric motor driven auxiliary cooling water pump with discharge
connection above the floor.
Two through-flow traveling screen assemblies with electric motor drives, and screen wash
systems for cleaning.
Removable bar grates that can be replaced with individual stop log assemblies for each
circulating water pump bay.
Buried concrete circulating water pipe for both the current and future power blocks.
Above ground large diameter steel circulating water pipe. Interconnecting piping, valves,
instrumentation, and accessories.
General Description
Two 50 percent circulating water pumps circulate water from the circulating water pump sump in the sea
water intake structure to the condenser and back to the sea via the effluent channel and outfall structure.
The intake structure shall be arranged to allow individual pump cells to be taken out of service by
installation of a stop log to allow dewatering. Each pump cell shall be provided with a bar screen and
traveling screen to protect the pumps and remove debris.
A permanent monorail system shall be provided to remove the bar screens and traveling screens for
cleaning or maintenance and to install the stop logs. The monorail system shall include an electric hoist
designed for the heaviest piece.
The intake structure shall be designed to include two future cells for the future circulating water pumps
and auxiliary cooling water pump for the future power block. Openings shall be provided in the intake
structure of the same size and arrangement as what is provided for the current pumps and the openings
shall be permanently covered.
The intake structure shall also include two pump cells for use by the LNG Facility Owner. Pump, bar
screen, and traveling screen equipment and design details will be provided by the LNG Facility Owner.
The effluent channel shall be sized for both the current and future power blocks. The effluent channel
shall also be sized to accommodate the discharge water from the LNG Facility at the same time both
power blocks are operating. Water flow from the LNG Facility will be approximately 10% the rate of the
power plant circulating water system. Exact values will be provided at a later date.
A motor operated butterfly valve shall be provided at the discharge of each circulating water pump. Valve
opening and closing speed and position shall be determined in accordance with the pump manufacturer’s
recommended starting procedure and the Contractor’s water hammer analysis.
The auxiliary cooling water pump shall supply 100 percent of the cooling water required for Closed Cycle
Cooling Water Heat Exchangers when the circulating water pumps are not operating. The auxiliary
cooling water pump shall also be used for filling the circulating water system prior to starting the
circulating water pumps.
Buried concrete circulating water pipe shall be installed for both the current power block and future power
block. The buried pipe for the future power block shall be terminated at grade and the pipe openings shall
be covered to allow future connection.
A system transient (water hammer) analysis shall be performed on the circulating water system. A
circulating water sump flow study shall be performed for large pumps.
Since the cooling water supply is the ocean, a thorough analysis of the hydraulic gradient for the system
is required. Hydraulic gradients must be determined for low, normal and high levels and at summer and
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winter water temperatures. Vacuum priming of the condenser water boxes will be required and a fixed or
adjustable weir may be required at the outfall to ensure that priming can be maintained under all
operating conditions.
Vacuum pumps for priming and condenser air extraction shall be supplied with the coldest cooling water
available, i.e. circulating or auxiliary cooling water.
The system design pressure shall be set based on the circulating water pump shutoff head. The auxiliary
cooling water pump shutoff head shall not exceed the circulating water system design pressure unless a
relief valve is provided to protect the circulating water system.
All vent, drain, and instrument connections shall be furnished with a single valve for isolation.
Materials of Construction
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Circulating water pumps – Super austenitic stainless steels like AL6XN or super duplex
stainless steels like Ferralium 255 for the suction bell, bowl, column, impeller, and shaft with
cutless rubber bearings.
Piping  24 inch (610 mm), above grade - ASTM A53 or A106 Gr. B, with interior dielectric
coating (if needed, depending on water quality)
Piping > 24 inch (610 mm), above grade - ASTM A139 Gr. B, with interior dielectric coating (
if needed, dependent on water quality)
Piping > 24 inch, below grade – AWWA C301 or C303 concrete cylinder pipe, testable joints
Valves 2 inch (50 mm) and smaller – Forged steel ASTM A105
Valves 2-1/2 inch (65 mm) and larger – Cast steel ASTM A216 WCB
Large Butterfly valves – Cast or ductile iron, rubber lined, rubber or nylon coated discs.
Controls and Instrumentation
The auxiliary cooling and circulating water pumps shall be controlled by the DCS. All pumps shall be
manually started and stopped from the DCS operator interface station.
The system shall be fully primed with the auxiliary cooling water pump prior to starting a circulating water
pump. Level transmitters mounted on the upper water boxes must detect level in the water boxes as a
permissive for starting the circulating water pumps.
A pump start command shall initiate opening of the motor operated pump discharge valve with a
simultaneous pump start command or with a delayed pump start command depending on the pump
manufacturer’s recommendations, and water hammer analysis.
Operation of the auxiliary cooling water pump shall be interlocked with the circulating water pumps to
prevent it from operating at the same time if the discharge heads are not compatible.
01630.3.12
Heat Recovery Steam Generators (SGA)
Function
The Heat Recovery Steam Generators (HRSGs) generate steam for power generation using the hot
exhaust gas from the Combustion Turbine Generators (CTGs). The HRSGs are horizontal gas flow
natural circulating units with integral economizers, evaporators, steam drums, superheaters, reheaters,
and attemperators.
Major Components
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Three HRSGs shall be furnished as part of the power block. Each HRSG shall include the following major
components:
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High pressure economizers, steam drum, evaporators, superheaters, and attemperators.
Reheater and reheat attemperator.
Intermediate pressure economizers, steam drum, evaporators, and superheaters.
Low pressure economizers, steam drum, evaporators, and superheaters.
Low pressure economizer recirculation and bypass system.
Inlet duct expansion joints and transition piece.
Exhaust expansion joint, breeching, stack, and stack isolation damper.
HRSG bypass stack, expansion joints, diverter damper, and damper sealing system.
HRSG structure, casing, ductwork, and platforms.
A full system of thermal insulation and lagging.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The HRSGs are triple pressure units with reheat. High temperature exhaust gas from each combustion
turbine enters its respective HRSG upstream of the last stage HP superheater/reheater assembly. The
gases travel horizontally through the HRSG heating each successive pressure level and then are
exhausted through the stack to atmosphere. Emissions are controlled in the CTGs to meet current World
Bank emissions standards as specified herein with the CTGs burning both diesel and natural gas.
The HRSGs do not include duct burners or SCR systems.
Materials of Construction
Materials of construction for each HRSG shall be as specified in Section 15511 herein.
Controls and Instrumentation
HRSG operation shall be controlled by the plant Distributed Control System (DCS). During normal
operation, each HRSG shall operate in sliding pressure mode based primarily upon CTG load and
ambient conditions. At some reduced load, the steam turbine may be required to control the pressure in
order to prevent excessive steam/water velocities, moisture carryover, and other damaging effects in the
HRSG at reduced operating pressures.
Steam temperature at the outlet of the last stage HP superheater and reheater shall be controlled by
interstage spray attemperators. Every effort shall be made to minimize attemperator spray during normal
full load operation.
01630.3.13
Boiler Vents and Drains (SGF)
Function
The Boiler Vents and Drains System collects blowdown and drains from the heat recovery steam
generators (HRSGs), economizer drains, evaporator drains, and steam line drains in the HRSG area.
HRSG, economizer, evaporator, and steam line drains shall be routed to the HRSG blowdown tanks
where flashing steam is separated from the water at near atmospheric pressure. The water collected in
the blowdown tanks is quenched and routed to the cycle makeup treatment system (WTD) recycle tank.
Steam produced from flashing drains is vented to the atmosphere.
Major Components
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The Boiler Vents and Drains System shall include the following major components:
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One vertical blowdown tank for each HRSG.
One quench water control valve for each blowdown tank.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
HRSG drains and steam line drains in the HRSG area, that operate during plant startup and operation
shall be piped to drain headers that run to the blowdown tanks. Continuous, intermittent, and startup
blowdown lines from the HP and IP drums shall be individually piped to the blowdown tank. Hot drains
entering the blowdown tanks partially flash to steam. The steam is vented to atmosphere and the liquid is
drained to the plant cycle makeup treatment system.
Drain inlets shall be mounted tangentially to the tanks to provide cyclonic separation of the steam and
liquid phases of the drains. Chrome alloy steel wear plates shall be provided on the interior of the tanks
at the same elevation as the tangential drain connections. Though vented to the atmosphere, the tanks
shall be designed in accordance with ASME Section VIII, Div. 1, for 100 psig (690 kPa) design pressure
and 650 degrees F (345 degrees C) design temperature.
Chrome alloy piping shall be used for at least 20 diameters downstream of the blowdown valves.
A temperature element and control valve shall be provided to supply service water to the blowdown tank
drain line to quench the drains to a temperature of approximately 140 degrees F (60 degrees C). The
drain piping shall include a loop seal or mixing chamber that will assure that the temperature control
element is always submerged.
Materials of Construction
Materials of construction shall be as follows:







Blowdown Tanks – Carbon steel ASME SA 515, Gr. 70, minimum with internal chrome alloy
steel wear plates.
Piping 2-1/2 inch (65 mm) and larger - carbon steel, A53 or A106, Gr. B, schedule 80
minimum for pipe upstream of tank.
Piping 2 inch (50 mm) and smaller – carbon steel, A53 or A106, Gr. B, schedule 80 minimum.
Superheater drain headers – 2.25 CR alloy steel, ASTM A335, Gr. P22
Valves 2-1/2 inch (65 mm) and larger – CL150, cast steel, ASTM A216 WCB, CL150, RF
flanged.
Valves 2 inch (50 mm) and smaller – CL600, forged steel, ASTM A105, socket weld.
Welding Code – W2
Controls and Instrumentation
A temperature element monitors the temperature of the blowdown tank drain to the waste water
treatment. The temperature signal is displayed on the DCS operator interface stations and is used to
control the control valve that adds water to quench the blowdown stream to approximately 140 degrees F
(60 degrees C).
01630.3.14
High Pressure Steam (SGG)
Function
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The HP Steam System shall deliver superheated steam from the HRSG superheater outlets to the steam
turbine stop and control valve(s). The HP steam system shall also supply steam to the steam turbine
gland seal system.
The HP Steam System shall include the capability to bypass the steam turbine during unit startups,
shutdowns, and load rejections. The bypass system capacity shall be 100 percent of the steam produced
in the HRSG when the combustion turbine is at base load (guarantee conditions).
Major Components
The high pressure (main) steam system shall include the following major components:



Interconnecting piping, valves and accessories.
Flow, temperature and pressure instrumentation.
Full capacity steam bypass system.
General Description
HP steam shall be piped from each HRSG high pressure superheater outlet to a common supply header
which shall supply HP steam from each HRSG to the steam turbine and to the steam turbine gland
sealing system. The steam lines from each HRSG shall include a turbine bypass system, an isolation
valve, and flow, pressure, and temperature measuring devices along with power operated drains (where
required).
Each of the steam turbine bypass systems shall include a combination pressure reducing and
desuperheating valve, or a pressure reducing valve and a separate steam desuperheater. During steam
turbine bypass operation, the HP steam shall be conditioned to cold reheat steam conditions and returned
to the cold reheat piping ahead of the IP steam tie in to the cold reheat piping and the HRSG reheater
inlet.
Chrome alloy piping shall be used for at least 40 diameters downstream of the HP bypass desuperheater
if the CRH system piping is carbon steel.
The HP steam piping shall be provided with a drip leg near the turbine stop valve(s) for removal of
condensate from the steam line. Drip legs shall also be provided at all low points in the piping.
Condensate collected in the drip legs shall be directed to the HRSG blowdown tank(s) and/or the
condenser.
HP steam piping shall be designed and tested in accordance with ASME Code for Pressure Piping B31.1,
Power Piping. Steam line drains shall be designed in accordance with the ASME Turbine Water
Induction Prevention Standard.
Materials of Construction
Materials of construction shall be as follows:





Piping 2-1/2 inch (65 mm) and larger – 9 CR, alloy steel, ASTM A335, Gr. P91, seamless
Piping 2 inch (50 mm) and smaller – 9 CR, alloy steel, ASTM A335, Gr. P91 or 2.25 CR, alloy
steel, ASTM A335, Gr. P22
Valves 2-1/2 inch (65 mm) and larger – cast steel, ASTM A217 C12A, butt weld ends.
Valves 2 inch (50 mm) and smaller – forged steel, ASTM A182, Gr. F22 or ASTM A182 Gr.
F91, socket weld.
Welding Codes – W1, W2 (refer to Section 01400, Supplemental Q210 for definition)
Controls and Instrumentation
Source: 01630, 2005
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Steam pressures, temperatures and flows shall be transmitted to the DCS and displayed on the DCS
operator interface stations. The pressure and temperature compensated steam flow signal shall be used
in the HP drum three element level control scheme and the HP bypass valve control scheme. The HP
superheater outlet temperatures shall be used for control of the HP steam desuperheater spray control
valve.
Steam turbine throttle pressure and temperatures shall be monitored in the DCS. Separate
instrumentation, provided by the turbine manufacturer, shall be provided to supply this information to the
steam turbine control system.
Steam pressure shall be used in the control for the HP bypass system. Steam pressure shall also be
measured to determine the saturation temperature for the HP steam header. Prior to steam turbine
synchronizing and controlling HP header pressure, the HP steam bypass valves shall be controlled to
pressure setpoints generated in the DCS. As the pressure rises to the set point, the bypass valve shall
modulate open as needed to maintain the HP steam pressure set point.
The bypass steam temperature shall be monitored in the DCS and shall be used to control the bypass
steam desuperheater outlet temperature. Temperature elements shall be located as far downstream of
the desuperheater as possible, but upstream of the bypass tie-in to the cold reheat piping.
HP steam bypass desuperheater spray water flow (in the feedwater system) shall be measured in the
DCS and used to calibrate the spray flow logic.
The HP steam bypass spray control valve, spray block valve and bypass valve shall have closed limit
switches indicating closed valve position. The HP steam bypass valve shall have a solenoid operated
valve in the air supply that can be energized to allow the control system to modulate the valve and deenergized to close the bypass valve. This provides for an immediate closing of the valve in the event of
DCS or positioner failure or in the event of high bypass steam enthalpy, loss of condenser vacuum, or hot
reheat path blocked.
Temperature elements shall be installed in the HP steam piping drip legs. These temperatures shall be
monitored in the DCS. When steam temperatures nearing saturation temperature are detected, the DCS
shall alarm this condition and alert the operator to open the associated drain valve.
01630.3.15
Low Pressure Steam (SGH)
Function
The LP Steam System shall deliver superheated steam from the HRSG LP superheater outlets to the
steam turbine admission stop and control valves(s).
The LP Steam System shall include the capability to bypass the steam turbine, during unit startups,
shutdowns, and load rejections, if required by the Supplier’s design. The bypass system capacity shall be
100 percent of the LP steam produced in the respective HRSG when the combustion turbine is at base
load (guarantee conditions).
Major Components
The low pressure steam system shall include the following major components:



Interconnecting piping, valves and accessories.
Flow, temperature and pressure instrumentation.
Full capacity steam bypass system.
General Description
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LP steam shall be piped from each HRSG low pressure superheater outlet to a common supply header,
which shall supply LP steam to the steam turbine. The steam lines from each HRSG shall include a
turbine bypass system, a unit isolation valve, and flow, pressure, temperature and level measuring
devices along with power operated drains (where required).
If LP steam turbine bypass systems are required for the Supplier’s design, each system shall include a
pressure reducing valve and a steam desuperheater (or a combination valve/desuperheater) if required to
protect condenser. During LP steam turbine bypass operation, the LP steam shall be conditioned to a
suitable pressure and temperature and admitted to the condenser.
The LP steam piping shall be provided with drip legs at all low points in the piping. Condensate collected
in the drip legs in the steam turbine area shall be directed to the condenser. Condensate collected in the
drip legs elsewhere shall be directed to the HRSG blowdown tank(s) and/or the condenser.
The steam bypass piping downstream of the desuperheater shall be well drained (sloped all the way to
the condenser) or provided with low point drip legs with dual level switches and power operated drain
valves.
Materials of Construction
Materials of construction shall be as follows:





Piping 2-1/2 inch (65 mm) and larger – Carbon steel, ASTM A53 or A106, Gr. B
Piping 2 inch (50 mm) and smaller – Carbon steel, ASTM A53 or A106, Gr. B
Valves 2-1/2 inch (65 mm) and larger – Cast steel, ASTM A216 WCB, flanged or butt welded
ends
Valves 2 inch (50 mm) and smaller – Forged steel, ASTM A105, socket weld: gate, globe, or
ball style
Welding Codes – W1, W2 (refer to Section 01400, Supplemental Q210 for definition)
Controls and Instrumentation
Steam pressures, temperatures and flows shall be transmitted to the DCS and displayed on the DCS
operator interface stations. The pressure and temperature compensated steam flow signal shall be used
in the LP drum three element level control scheme and the LP steam bypass valve control scheme.
LP steam turbine admission pressure and temperatures shall be monitored in the DCS. Separate
instrumentation, provided by the turbine manufacturer, shall be provided to supply this information to the
steam turbine control system.
Level switches shall be installed in the steam piping drip legs. The level switches shall be monitored in
the DCS. When water is detected, the DCS shall alarm this condition and automatically open the
associated drain valve. On the drip leg on the LP steam common header, a second (high-high) level
switch shall be provided for DCS alarming of further increase in level above the high level alarm level.
LP steam bypass desuperheater flow (from the condensate system) shall be monitored in the DCS and
used to calibrate the spray flow logic.
LP steam piping shall be designed and tested in accordance with ASME Code for Pressure Piping B31.1,
Power Piping. Steam line drains shall be designed and operated in accordance with ASME TDP-1
(Recommended Practices for the Prevention of Water Damage to Steam Turbines used for Electric Power
Generation).
The LP steam bypass spray control valve, spray block valve and bypass valve shall have limit switches
indicating closed valve position.
Source: 01630, 2005
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The temperature elements in the LP steam bypass lines to the condenser shall be located as close to the
condenser as is practical.
The LP steam bypass valves shall have a solenoid operated valve in the air supply that can be energized
to allow the control system to modulate the valve and de-energized to close the bypass valve. This
provides for an immediate closing of the valve in the event of DCS or positioner failure or in the event of
high bypass steam enthalpy or loss of condenser vacuum.
01630.3.16
Hot Reheat Steam (SGJ)
Function
The Hot Reheat Steam System shall return reheated steam (Hot Reheat Steam) from the HRSGs to the
reheat stop and control valves of the steam turbine.
The Hot Reheat Steam system shall include the capability to bypass the steam turbine, during unit
startups, shutdowns, and load rejections. The bypass system capacity shall be 100 percent of the sum of
the cold reheat steam from the HP steam turbine (or HP steam bypass) and the IP steam produced when
the associated combustion turbine is at base load (guarantee conditions). Bypass steam shall be
conditioned and dumped into the condenser.
Major Components
The reheat steam system shall include the following major components:



Interconnecting piping, valves, and accessories.
Flow, temperature, and pressure instrumentation.
Full capacity steam bypass system.
General Description
Reheat steam from each HRSG shall be piped to a common header, which shall return the hot reheat
steam to the steam turbine reheat stop and control valve(s). The hot reheat steam line from each HRSG
shall include a reheater safety valve, a turbine bypass system, an isolation valve, and instrumentation for
temperature and pressure.
Each of the steam turbine bypass systems shall include a combination pressure reducing and
desuperheating valve, or a separate pressure reducing valve and a steam desuperheater. During steam
turbine bypass operation, the hot reheat steam shall be conditioned to a pressure and temperature
suitable for admission to the condenser.
The hot reheat steam piping shall be provided with drip legs at all low points in the reheat piping.
Condensate collected in the drip legs shall be directed to the HRSG blowdown tank (s) and/or the
condenser.
Chrome alloy pipe shall be used for the first 40 diameters downstream of the bypass valve.
The steam bypass piping downstream of the desuperheater shall be well drained (sloped all the way to
the condenser) or provided with low point drip legs with dual level switches and power operated drain
valves.
Reheat steam piping shall be designed and tested in accordance with ASME Code for Pressure Piping
B31.1. Steam line drains shall be designed and operated in accordance with the ASME Turbine Water
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Induction Prevention standard. Reheater safety valves shall be provided in accordance with the ASME
Boiler and Pressure Vessel Code, Section I.
Materials of Construction
Materials of construction shall be as follows:





Piping 2-1/2 inch (65 mm) and larger – 9 CR, alloy steel, ASTM A335, Gr. P91, seamless or
ASTM A335, Gr. P22, seamless if appropriate.
Piping 2 inch (50 mm) and smaller – 2.25 CR, alloy steel, ASTM A335, Gr. P22.
Valves 2-1/2 inch (65 mm) and larger – Cast steel, ASTM A217 C12A, butt weld ends.
Valves 2 inch (50 mm) and smaller – Forged steel, ASTM A182, Gr. F22, socket weld.
Welding Codes – W1, W2 (refer to Section 01400, Supplemental Q210 for definition)
Controls and Instrumentation
Steam pressures and temperatures shall be transmitted to the DCS and displayed on the DCS operator
interface stations. The reheater outlet temperatures shall be used for control of the reheat steam
attemperator spray control valve.
Steam turbine hot reheat pressure and temperatures shall be monitored in the DCS. Separate
instrumentation, provided by the turbine manufacturer, shall be provided to supply this information to the
steam turbine control system.
Steam pressure shall be used in the control of the hot reheat bypass system. The hot reheat steam
bypass valves shall be controlled to pressure setpoints generated in the DCS. As the pressure rises to
the set point, the bypass valve shall modulate open as needed to maintain the hot reheat steam pressure
set point. The bypass steam temperature and pressure shall be monitored in the DCS and used to
control the bypass steam desuperheater outlet enthalpy for condenser protection.
Temperature elements shall be installed in the hot reheat steam piping drip legs. These temperatures
shall be monitored in the DCS. When steam temperatures nearing saturation temperature are detected,
the DCS shall alarm this condition and alert the operator to open the associated drain valve.
The hot reheat steam bypass desuperheater flow (in the condensate system) shall be monitored in the
DCS and used to calibrate the spray flow logic and to monitor possible water flow into an idle bypass line.
The hot reheat bypass spray control valve, spray block valve and the bypass valve shall have limit
switches indicating closed valve position.
The temperature elements in the hot reheat steam bypass lines to the condenser shall be located as
close to the condenser as is practical.
The hot reheat steam bypass valve shall have a solenoid operated valve in the air supply that is
energized to allow the control system to modulate the valve and is de-energized to close the bypass
valve. This provides for an immediate closing of the valve in the event of DCS or positioner failure or in
the event of high bypass steam enthalpy or loss of condenser vacuum.
01630.3.17
Cold Reheat Steam (SGK)
Function
The Cold Reheat Steam System shall return exhaust steam (Cold Reheat Steam) from the high pressure
steam turbine to the HRSG reheaters.
Source: 01630, 2005
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Major Components
The cold reheat steam system shall include the following major components:


Interconnecting piping, valves and accessories.
Flow, temperature, level and pressure instrumentation.
General Description
Cold reheat steam shall be piped from the high pressure turbine exhaust connection through a common
line that includes safety valves and then splits to the reheaters at each HRSG. The cold reheat return line
to each HRSG shall include an isolation valve, a flow balancing control valve, reheater safety valves and
instrumentation for flow, temperature, level, and pressure. The flow balancing valves shall be suitable for
maintaining appropriate return steam flow back to each HRSG.
The cold reheat system shall also receive steam from the HP steam turbine bypass systems. The bypass
steam shall be conditioned to cold reheat temperature and pressure and then admitted to the cold reheat
piping upstream of the IP steam connection from the HRSG to the cold reheat piping. The cold reheat
steam piping shall be provided with drip legs at low points in the piping for removal of condensate from
the steam lines. Condensate collected in the drip legs shall be directed to the HRSG blowdown tank(s)
and/or the condenser.
Cold reheat steam piping shall be designed and tested in accordance with ASME Code for Pressure
Piping B31.1. Steam line drains shall be designed and operated in accordance with the ASME Turbine
Water Induction Prevention standard. Cold reheat piping safety valves or rupture disk(s) shall be in
accordance with ASME Boiler and Pressure Vessel Code, Section VIII. Reheater safety valves shall be
in accordance with the ASME Boiler and Pressure Vessel Code, Section I.
Materials of Construction
Materials of construction shall be as follows:





Piping 2-1/2 inch (65 mm) and larger – Carbon steel, ASTM A53 or A106, Gr. B seamless; or
ASTM A335, Gr. P11 or P22 for alloy application.
Piping 2 inch (50 mm) and smaller – Carbon steel, ASTM A53 or A106, Gr. B, seamless; or
A335, Gr. P22 for alloy applications.
Valves 2-1/2 inch (65 mm) and larger – Cast steel, ASTM A216 WCB, or ASTM A217, Gr.
WC9 for alloy butt weld end.
Valves 2 inch (50 mm) and smaller – Forged steel, ASTM A105, or, ASTM A182, Gr. F22 for
alloy socket weld.
Welding Codes – W1, W2 (refer to Section 01400, Supplemental Q210 for definition)
Controls and Instrumentation
Steam pressures, temperatures and flows shall be transmitted to the DCS and displayed on the DCS
operator interface stations. The pressure and temperature compensated HRSG IP steam flow signal
shall be used in the IP drum three element level control scheme.
Steam turbine exhaust pressures and temperatures shall be monitored in the DCS. The steam flow to
each HRSG shall be measured, pressure and temperature compensated, and the cold reheat flow control
valves modulate to control the cold reheat steam flows in proportion to the individual HRSG steam flow
contributions.
Level switches shall be installed in the steam piping drip legs. The level switches shall be monitored in
the DCS. When water is detected, the DCS alarms this condition and automatically opens the associated
Source: 01630, 2005
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power operated drain valve. On the drip leg on the cold reheat steam common header, a second (highhigh) level switch shall be provided for DCS alarming of further increase in level above the high level
alarm/interlock level.
Special attention shall be paid to predicted performance at low load operating conditions, such as startup
or one combustion turbine operating at part load with the steam turbine on line. These conditions can
result in high cold reheat steam temperatures (greater than 775 F) which require the selection of chrome
alloy piping for the cold reheat line.
01630.3.18
Steam Turbine Vents and Drains (SGL)
Function
The Steam Turbine Vents and Drains System collects leak off, blowdown, and drains from the steam
turbine and the steam turbine area. Drains shall be routed to the turbine area drains tank where flashing
steam is separated from the water at near atmospheric pressure. The water collected in the blowdown
tanks is quenched and routed to the cycle makeup treatment system (WTD) recycle tank. Steam
produced from flashing drains is vented to the atmosphere.
Major Components
The Steam Turbine Vents and Drains System shall include the following major components:



One vertical blowdown tank.
One quench water control valve.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Steam turbine drains and steam line drains in the steam turbine area that operate during plant startup and
operation shall be piped to drain headers that run to the blowdown tank. Hot drains entering the
blowdown tank partially flash to steam. The steam is vented to atmosphere and the liquid is drained to
the cycle makeup treatment system.
Drain inlets shall be mounted tangentially to the tank to provide cyclonic separation of the steam and
liquid phases of the drains. Chrome alloy steel wear plates shall be provided on the interior of the tanks
at the same elevation as the tangential drain connections. Though vented to the atmosphere, the tanks
shall be designed in accordance with ASME Section VIII, Div. 1, for 100 psig (690 kPag) design pressure
and 650 degrees F (345 degrees C) design temperature.
A temperature element and control valve shall be provided to supply service water to the blowdown tank
drain line to quench the drains to a temperature of approximately 140 degrees F (60 degrees C). The
drain piping shall include a loop seal or mixing chamber that will assure that the temperature control
element is always submerged.
Materials of Construction
Materials of construction shall be as follows:



Blowdown Tanks – Carbon steel ASME SA 515, Gr. 70, minimum with internal chrome alloy
steel wear plates.
Piping 2-1/2 inch (65 mm) and larger - carbon steel, A53 or A106, Gr. B, schedule 80
minimum for pipe upstream of tank.
Piping 2 inch (50 mm) and smaller – carbon steel, A53 or A106, Gr. B, schedule 80 minimum.
Source: 01630, 2005
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Superheated steam drain headers – 2.25 CR alloy steel, ASTM A335, Gr. P22
Valves 2-1/2 inch (65 mm) and larger – CL150, cast steel, ASTM A216 WCB, CL150, RF
flanged.
Valves 2 inch (50 mm) and smaller – CL600, forged steel, ASTM A105, socket weld.
Controls and Instrumentation
A temperature element shall monitor the temperature of the blowdown tank drain to the cycle makeup
treatment system. The temperature signal shall be displayed on the DCS operator interface stations and
shall be used to operate the control valve that adds water to quench the blowdown stream to
approximately 140 degrees F (60 degrees C).
01630.3.19
Steam Turbine Generator (TGA)
Function
The Steam Turbine Generator (STG) generates electric power using high pressure, reheat, and low
pressure steam produced in the three Heat Recovery Steam Generators (HRSGs). The STG shall be an
electric utility grade unit designed specifically for combined cycle service.
Major Components
Each Steam Turbine Generator shall include the following major components:









Complete steam turbine with high pressure, intermediate pressure, and low pressure sections
Hydrogen or air cooled generator
Turbine control system
Control and monitoring equipment
Protective relay panels
Lube oil conditioning system
Turbine enclosure with sound attenuation
A full system of thermal insulation and lagging.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The STG shall consist of high pressure, intermediate pressure, and low pressure sections designed
specifically for combined cycle service. The STG shall be a condensing unit with single or dual flow
downward exhaust. High pressure steam shall enter the HP turbine through one or more main steam
stop and control valves. The exhaust of the HP turbine shall return steam to the cold reheat inlets of the
HRSGs. Hot reheat steam from the HRSGs will combine and enter the intermediate pressure steam
turbine through reheat stop/control valves. The exhaust of the IP turbine section shall be ducted to the
inlet of the low pressure turbine(s) and then discharged to the steam surface condenser. Low pressure
steam from LP section of the HRSGs shall be admitted to the low pressure turbine section through LP
steam admission stop and control valves furnished by the steam turbine manufacturer.
Materials of Construction
Materials of construction for the STG shall be as specified in Section 15561 herein.
Controls and Instrumentation
Steam Turbine Generator operation shall be controlled by STG manufacturer’s dedicated control system.
The plant Distributed Control System (DCS) will have supervisory control and monitoring functions that
fully replicate the manufacturer’s control system operator interface. During normal operation, the STG
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shall operate in sliding pressure mode based primarily upon CTG/HRSG load and ambient conditions. At
some reduced load, the steam turbine may be required to control the pressure in order to prevent
excessive steam/water velocities, moisture carryover, and other damaging effects in the HRSGs at
reduced operating pressures. A steam turbine bypass system shall be provided as described elsewhere
herein.
Special provisions shall be included to prevent the admission of water into the steam turbine during
operation. These provisions shall be in accordance with either the current edition of ASME TDP-1 or the
standards of the STG manufacturer, whichever is more stringent.
01630.3.20
Combustion Turbine Generators (TGH)
Function
Three (3) Combustion Turbine Generators (CTGs) produce shaft power to generate electricity and
produce hot exhaust gases that are used to produce steam for power generation in the Heat Recovery
Steam Generators (HRSGs).
Major Components
Each Combustion Turbine Generator shall include the following major components:




“F” Class CTG machine complete with a full complement of auxiliary equipment, enclosures,
walk-in compartments, and controls.
Inlet filter silencer.
Thermal insulation and lagging.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The CTGs shall be manufacturer’s standard “F” Class machines designed for dual fuel operation in a
combined cycle configuration. Each CTG shall be a regularly manufactured unit with a proven history of
superior reliability, maintainability, and performance in a power plant environment. Exhaust emissions
shall be controlled in the CTGs to meet current World Bank emissions standards as specified herein
when burning both diesel and natural gas.
Materials of Construction
Materials of construction for each CTG shall be as specified in Section 15562 herein.
Controls and Instrumentation
Combustion Turbine Generator operation shall be controlled by CTG manufacturer’s dedicated control
system (if separate from the DCS). If separate from the manufacturer’s dedicated control system, the
DCS shall have full supervisory control and monitoring capability as specified in Section 17101 herein.
01630.3.21
Fire Protection Water Supply and Storage (WSE)
Function
The Fire Protection Water Supply and Storage System receives water from the desalination plant and
stores it in the Fire Water Storage Tank and Service/Fire Water Tank. Full capacity fire water pumps, one
electric motor driven and one diesel engine driven, and one electric motor driven pressure maintenance
Source: 01630, 2005
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pump, supply fire water under pressure to the Site Fire Protection System, which includes fire hydrants
and fixed water suppression systems.
Major Components
The Fire Protection Water Supply and Storage System shall include the following major components:







One electric motor driven fire pump.
One diesel engine driven fire pump.
One diesel storage tank.
One pressure maintenance pump.
Interconnecting piping, valves, instrumentation, and accessories.
One combined service/fire water storage tank with 250,000 gallons (946,000 litres) net
capacity for service water and a sufficient net reserve capacity of fire water to meet
applicable Code requirements. In no case shall the reserve fire water storage capacity be
less than 250,000 gallons (946,000 litres) net. Minimum total net tank capacity is therefore
500,000 gallons (1,892,000 litres). The fire water storage volume shall be protected by a
standpipe so that it cannot be used by the service water system.
One fire water storage tank with sufficient net capacity to meet applicable Code
requirements. In no case shall the fire water storage capacity be less than 250,000 gallons
(946,000 litres) net.
General Description
Each fire pump shall be a full capacity, horizontal, double suction, horizontal split case style pump. One
shall be electric motor driven and the other shall be diesel engine driven.
The fire pumps shall be of cast iron, bronze fitted construction. Each pump shall be furnished with a
pump control panel that senses pressure in the fire system and starts the pump when the fire system
pressure falls below the set pressure.
The pressure maintenance pump shall be full capacity, electric motor driven, and of cast iron bronze or
stainless fitted construction. The pump shall be furnished with a pump control panel that senses pressure
in the fire system and starts the pump when the fire system pressure falls below the set pressure.
A recirculation line which branches to the Fire Water Storage Tank and the Service/Fire Water Storage
Tank, with flow meter, shall be provided for periodic flow testing of the pumps.
A diesel storage tank shall be provided to store enough diesel for 12 hours operation of the diesel engine.
Fire water flows by gravity from the storage tanks to the suctions of the fire water pumps. Normally the
pressure maintenance pump will operate to maintain a pressure in the fire mains above the starting set
pressures of the motor and diesel driven fire pumps. When a fire suppression system is actuated, or a
hydrant is opened, the pressure maintenance pump cannot maintain pressure in the fire mains, and as
the fire main pressure drops, the motor driven fire pump shall start, and if the main pressure continues to
fall, the diesel fire pump shall start.
The recommendations of NFPA Standard 850 shall be followed.
Materials of Construction



Fire water pumps – Cast iron casings, carbon steel shafts, bronze impellers and shaft
sleeves.
Piping – Carbon steel ASTM A53 or A106 Gr. B seam welded.
Valves 2 inch (50 mm) and smaller – CL 600, socket weld, forged steel ASTM A105
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Valves 2-1/2 inch (65 mm) and larger – Class 175 WWP, flanged, cast iron (ASTM A126
Class A or equivalent), with bronze trim (ASTM B61 or equivalent), UL listed / FM approved
(Gate and globe valves to be OS&Y)
Controls and Instrumentation
Each fire water pump and the pressure maintenance pump shall be controlled from a local fire pump
control panel. The pumps may be started manually or automatically at predetermined pressure setpoints
for each pump. Typical starting pressures for the pumps are 135 psig (930 kPa) for the motor driven fire
pump and 125 psig (865 kPa) for the diesel driven fire pump. Once started, the fire pumps shall only be
shut down from the local panel. Fire pump status shall be indicated remotely on the Fire Alarm
Annunciator Panel (FAAP) in the control room.
A level switch on the diesel fire pump fuel tank monitors level in the tank and low level shall be alarmed
on the FAAP in the control room.
01630.4 Water Management Systems
This section contains system descriptions for each of the systems associated with water treatment and
use that will be constructed as part of this Project. These system descriptions describe the function, major
components, and basis for design for each system.
The system descriptions contained within this section are as follows:
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01630.4.1
Cycle Chemical Feed (FWE)
Steam Cycle Sampling and Analysis (SAC)
Service Water (WSC)
Potable Water (WSD)
Desalination (WTA)
Cycle Makeup Treatment (WTD)
Waste Collection and Treatment (WWC)
Oily Waste Drains (WWD)
Cycle Chemical Feed (FWE)
Function
The function of the Chemical Feed System is to provide conditioning chemicals to minimize corrosion and
scale formation throughout the condensate-feedwater-steam cycle for the combined cycle units. The
Cycle Chemical Feed System shall be designed to provide water conditioning chemicals to the main
steam generator cycle and the auxiliary boiler cycle.
Major Components
The Cycle Chemical Feed System shall include the following major equipment and components:

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Two oxygen cylinder manifolds
One oxygen feed skid containing two feed systems
Ammonia feed skid with local control panel, calibration column, and two full capacity pumps for
the main steam cycle
Ammonia feed skid with local control panel, calibration column, and two full capacity pumps for
the Auxiliary Boiler. Nonvolatile boiler additives could also be fed.
Boiler additive feed skid with local control panel, calibration column, and full capacity pump for
each pressure level.
Associated system piping, valves, instrumentation, and expansion joints.
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General Description
The Cycle Chemical Feed System for the main steam generator cycle consists of three subsystems that
operate independently of each other; an oxygen feed subsystem, a boiler additive feed subsystem, and
an ammonia feed subsystem. These subsystems are designed to minimize corrosion and corrosion
product transport in the steam cycle.
An ammonia solution shall be fed downstream of the condensate polisher and to the Auxiliary Boiler. The
solution is used for pH adjustment and shall be added as required to maintain a condensate pH within the
selected range of 9.2 to 9.6 at full flow. Ammonia shall also serve as the primary pH control for the
HRSG’s.
Oxygen is used as a part of oxygenated treatment (OT) to minimize corrosion and corrosion product
transport. There shall be provisions to feed at two points; the first is located downstream of the
condensate polisher and the second is located at the LP drum outlet. The oxygen feed equipment
consists of three subsystems; storage equipment (oxygen cylinders), oxygen feed skid (pressure
regulator, rotameter, control valve, and shutoff valves), and injection equipment (injection nozzle, local
isolation check valve, and relief valve).
A boiler additive system shall be used to feed sodium hydroxide in “trace caustic” mode to the LP, IP, and
HP drums.
Materials of construction

Oxygen cylinder manifolds - 316 stainless steel

Oxygen feed piping and accessories - 316 stainless steel

Ammonia feed pumps, piping and accessories - 304 stainless steel

Boiler additive feed pumps, piping and accessories - 316 stainless steel
Instrumentation and controls
Each chemical feed system shall be operated from local panels with feed rate set by the DCS. The
ammonia feed system shall be designed to feed the ammonia solution to maintain the pH (as measured
by specific conductance) of the boiler feed water between 9.2 and 9.6. Ammonia feed to the Auxiliary
Boiler shall be manually controlled. Oxygen is fed in proportion to condensate and boiler feed pump flow
and biased by downstream oxygen residual to achieve the selected oxygen concentration (30 to 50 ppb).
The oxygen feed system shall be interlocked to shut off oxygen feed at high cation conductivity levels,
high oxygen level in the HRSG downcomer, and also at low load. The boiler additive system shall be
configured to operate based on a manual set point via the DCS.
01630.4.2
Steam Cycle Sampling and Analysis (SAC)
Function
The function of the Steam Cycle Sampling and Analysis System is to provide a means to monitor the
performance and operation of the steam-condensate-feedwater cycle, to monitor the quality of various
process fluids, and to provide sufficient data to operating personnel for detection of any deviations from
control limits so that corrective action can be taken.
Major Components
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The Steam Cycle Sampling and Analysis System shall consist of the following major components:


One sample panel enclosure located in the Turbine Building.
One sample chiller.
General Description
The sample panel shall serve the entire power block. The panel is divided into four sections. These
include a primary cooling rack, a sample conditioning side, an analyzer section and a dry section.
The sample panel obtains samples for analysis from the following points of the steam-condensatefeedwater cycle:
Cycle water makeup.
Condensate pump discharge.
Individual Cation and Mixed Bed Condensate Polisher Effluent Samples
Condensate after chemical feed.
High-, intermediate-, and low-pressure drum boiler water of each HRSG.
High-, intermediate-, and low-pressure drum saturated steam of each HRSG.
Hot reheat steam of each HRSG.
High-pressure superheat steam of each HRSG.
These samples are routed to the sample panel, which provides temperature and pressure conditioning
and performs automatic analyses of the samples.
The primary cooling rack provides the following functions:
Receives all samples.
Provides blowdown of all samples to waste.
Provides primary cooling of all boiler water and steam samples.
The sample conditioning section provides the following functions:
Regulates flow of all samples.
Provides secondary cooling of all high purity samples.
Provides safety relief for overpressure protection of all downstream equipment for all samples.
Provides pressure control and indication for all samples.
Provides temperature indication for all samples.
Provides for measurement of specific conductance, cation conductivity, dissolved oxygen, sodium, silica,
and pH of selected sample streams.
Provides control and indication of sample flow rates to each analyzer.
Provides grab samples for each sample.
Provides high temperature protection of all analyzers with the use of high temperature shutoff valves.
Provides cooling water safety relief for overpressure protection of each sample cooler of the boiler water
and steam samples.
Provides drainage to waste for all sample streams and discharges from all analyzers.
Provides demineralized flush water for all analyzers/probes during a plant shutdown or for analyzer
calibration.
The analyzer section of the sample panel provides the following functions:
Transmits measurement signals of dissolved oxygen, sodium, and silica, from the sample conditioning
section of the sample panel to the dry section.
Provides sample sequencers, capable of controlling and varying the sequence schedule independently to
each analyzer for all samples sharing analyzers.
The dry section of the sample panel provides the following functions:
Transmits and indicates measurement signals of specific conductance, cation conductivity, dissolved
oxygen, sodium, silica, and pH to the plant Distributed Control System (DCS) for recording, data
acquisition, and data storage.
Houses all electrical and control components associated with the sampling system.
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The sample panel shall be located in the Turbine Building. The sampling area shall include a safety
shower and fume hood and shall have provisions for wet testing of the samples.
The sample panel is designed to condition the samples before analysis. First, the samples pass through
the primary cooling rack, located outside the polisher regeneration building. The primary cooling rack
includes primary coolers, isolation valves, and blowdown valves. The samples flow through the tube side
of the primary coolers where the majority of heat removal occurs. Closed cycle cooling water is used on
the shell side of the coolers. Final cooling takes place when the samples pass through the secondary
coolers. These coolers are similar to primary coolers, except that chilled water is provided by the
secondary sample chiller for sample cooling. The secondary sample chiller maintains the chilled water at
an adjustable set point and within a narrow range. Conditioned samples are sent to pH and conductivity
cells, sodium analyzers, and silica analyzers. Flow to each analyzer branch is controlled and indicated on
the flow indicators. Flow indicators should be set to maintain 500 to 1300 mL/min, sufficient to supply inline instrumentation and grab samples. Flow adjustment shall be done by adjusting the appropriate
needle valve. Grab samples can be taken at any time for laboratory analysis.
Materials of construction

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
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Metallic, wetted materials (valves, panel tubing, etc)* - 316 SS
Non-metallic items (conductivity cells, ph probes, etc) - manufactures standard
Panel face - painted 20 gauge carbon steel
Sample panel trough - 304 SS
Sample lines* - 316 SS
*Hot Reheat Steam and Superheat Steam shall be 316H SS until after the primary sample cooler.
Controls and Instrumentation
The Steam Cycle Sampling and Analysis System shall be controlled manually from the sample panel.
All analyzed parameters shall be transmitted to the DCS. If sequencers are used, then each sequencer
shall provide signals to the DCS to indicate which sample is currently active and the DCS shall hold all
other sample values at their last good value (or each sequencer shall provide separate sample signals to
the DCS, each of which is held at the last good value when not active). Where sample lines are shared
and selected manually, the DCS will be able to distinguish which sample is being fed to the analyzer
Alarms generated by the Steam Cycle Sampling and Analysis System are annunciated in the control
room and displayed on the DCS operator workstation.
To protect system equipment, protective actions shall be automatically taken if certain system
components malfunction. Protective actions include the following:
High Temperature Protection--The high temperature shutoff valves close on high temperature to protect
the associated equipment.
High Pressure Protection--The safety relief valves open on high pressure to protect the associated
equipment.
During a loss of flow condition, the associated sample line shall be automatically flushed with
demineralized water to protect probes and analyzers.
01630.4.3
Service Water (WSC)
Function
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The Service Water System receives service water from the desalination plant, the wastewater treatment,
or the back-up city water supply and stores it in the Service/Fire Water Storage Tank. The service water is
distributed for the following uses.
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HRSG blowdown tank cooling.
Steam turbine area drains tank cooling.
Miscellaneous service water users throughout the plant.
Component Description
The Service Water System shall include the following major components:


Two full capacity, horizontal, end suction, electric motor driven, service water pumps.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The Service Water System shall consist of two service water pumps, associated piping, valves and
instrumentation.
The service water pumps shall be of cast iron and bronze fitted. The pumps shall have recirculation lines
back to the Service/Fire Water Tank, with flow control orifices, to provide minimum flow protection for the
pumps.
Service water is supplied to the service water pumps from the Service/Fire Water Storage Tank through
an aboveground suction line. The pumps deliver service water to various users throughout the plant. All
service water piping shall be carbon steel.
All miscellaneous vent, drain, and instrument connections shall be furnished with a single ball or globe
valve for isolation.
Materials of Construction

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
Service water pumps – Cast iron construction, bronze fitted.
Piping – ASTM A53 Grade B ERW
Valves 2 inch (50 mm) and smaller – CL 600, forged steel ASTM A105, socket weld
Valves 2-1/2 inch (65 mm) and larger – CL 150, cast iron, flanged
Welding codes – W1, W2
Controls and Instrumentation
The service water pumps are controlled by the DCS. When required, one pump shall be started in
manual mode, and the other shall be in standby mode to automatically start in the event that the running
pump trips or header pressure becomes low.
A level transmitter on the Service/Fire Water Storage Tank monitors level in the tank and the level is
displayed on the DCS operator interface stations. The tank level signal shall be used to provide high and
low level alarms, and interlocks for pump operation.
A pressure transmitter monitors the service water pump discharge header, the pressure shall be
displayed on the DCS operator interface stations, and shall be used for start of the standby pump if one
pump is running and header pressure is low. Pressure shall be monitored on each service water pump
suction or discharge.
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01630.4.4
WORKS INFORMATION
EMPLOYER REVIEW
20October06
Potable Water (WSD)
Function
The Potable Water System draws water from the Service/Fire Water Storage Tank, treats the water to
make it suitable for potable water uses and provides it to the Potable Water Storage Tank. Potable water
supply pumps deliver water from the storage tank to building services, safety showers, and other
miscellaneous users.
Major Components
The Potable Water System shall include the following major components:
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One Potable Water Storage Tank with a minimum size of 75,000 litres.
Two full capacity Potable Water RO Feed Pumps.
One packaged Reverse Osmosis (RO) unit.
Hypochlorite, caustic, and soda ash injection systems.
Two full capacity Potable Water Supply Pumps.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Potable water is supplied to the Potable Water Storage Tank through an aboveground line from the
Service/Fire Water Storage Tank using the Potable Water RO Feed Pumps and RO unit in the Water
Treatment building.
The Potable Water Pumps shall be horizontal, end suction, electric motor driven pumps and shall have
recirculation lines to provide minimum flow protection for the pumps.
The Potable Water Storage Tank minimum size shall be sized to accommodate the full complement of
Employer staff along with all coincident miscellaneous uses. The tank shall be coated internally with an
epoxy coating system suitable for immersion in potable water. The tank shall be equipped with a vent
and air filter and piping inlet, outlet, overflow, drain, instrument connections, and corrosion control
prevention for exterior tank bottom plates.
All miscellaneous vent, drain, and instrument connections shall be furnished with a single ball or globe
valve for isolation.
The Potable Water System shall be designed and controlled to ensure that adequate water supply
pressure is maintained for all users at all times.
Materials of Construction


Potable Water Pumps – All wetted parts of stainless steel construction.
Piping, valves, and all other components exposed to potable water shall be metallic and shall
be certified for drinking water service in accordance with NSF/ANSI-61 or approved
equivalent standard.
Controls and Instrumentation
The Potable Water Pumps shall be controlled from the DCS operator stations. When required, one pump
shall be started in manual mode, and the other shall be in standby mode to automatically start in the
event that the running pump trips or header pressure becomes low.
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A level transmitter on the Potable Water Storage Tank monitors level in the tank and the level shall be
displayed on the DCS operator interface stations. This level indication shall also provide high and low
level alarms and interlocks for pump operation.
A pressure transmitter shall monitor the potable water discharge header. The pressure shall be displayed
on the DCS operator interface stations and used for start of the standby pump if one pump is running and
header pressure is low. Pressure shall be monitored on each potable water pump suction and discharge.
Flow metering for water supplied to the plant shall be measured with a mag-flow type flow meter complete
with flow integrator. The accuracy of this mag-flow meter shall be 0.5%. A second, identical,
independent mag-flow meter with integrator shall provide back-up redundancy. Water users within the
plant shall be metered with mag-flow type flow meters complete with flow integrator and accuracy of 1%.
01630.4.5
Desalination (WTA)
Function
The Desalination system shall be comprised of two water treatment processes: Sea Water Reverse
Osmosis Pretreatment, and Sea Water Reverse Osmosis. The function of the Desalination system is to
produce water of sufficient quantity and quality to satisfy all plant fresh water needs including feed for the
demineralization system.
Component Description
The Desalination system consists of the following major components and ancillary systems:
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Dissolved Air Flotation (DAF) equipment
Solids Processing equipment
Ultrafiltration (UF) equipment
Cartridge Filter equipment
Sea Water Reverse Osmosis (SWRO) equipment
Chemical Injection Systems
General description
The Sea Water Pretreatment process, referred to as Dissolved Air Flotation (DAF), shall consist of rapid
mix, flocculation and flotation processes. These processes together agglomerate particles into larger
particles and remove them from the water. The flotation process is preferred over a sedimentation
process since oil and grease and high concentrations of organic material could be present in the source
water. Clarified water from DAF is filtered through UF membranes, which is then desalinated by the Sea
Water Reverse Osmosis process.
Raw water from the ocean shall be dosed with sodium hypochlorite whenever required and blended with
effluent from the wastewater system and supplied to the rapid mixing tank. Sodium hypochlorite is dosed
after the raw water screens to prevent biofouling within the downstream processes.
The rapid mixer shall be comprised of a concrete chamber with a vertical turbine impeller designed to
provide rapid mixing. The concrete chamber shall be coated with appropriate material to negate any
corrosive effects of seawater. Water to be treated (raw water from ocean and recycled water from waste
treatment system) shall be dosed with sulfuric acid and coagulant as required. Provisions for addition of
polymer shall be included for dosing over the rapid mixer outlet weir.
The coagulated water flows under gravity to a common inlet chamber of the DAF unit. Flow shall be
distributed evenly to two DAF streams. Space shall be set aside for a third DAF stream when the second
combined cycle power block is added. Each DAF stream shall be sized at 50% of ultimate capacity. The
inlet and outlets of each flocculation stage shall be designed to direct flow diagonally across each
chamber from bottom to top to minimize flow short circuiting. An inlet penstock shall be provided to allow
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each DAF stream to be isolated. Manual drain valves shall be provided on each flocculation chamber to
allow draining down of the chamber to the solids processing area.
Each flocculation stream shall feed one DAF chamber. Flocculated water enters the DAF unit under a
baffle wall at the inlet riser. Recycle water (i.e., filtered water saturated with air under pressure) shall be
introduced at the inlet riser via distribution nozzles. The pressure drop across the recycle nozzles causes
the air to come out of solution, forming a microbubble air blanket.
The DAF recycle system shall consist of two variable speed recycle pumps (one operating, one standby)
that draw water from the UF Feed Tank, two air absorber vessels (one operating, one standby), and two
air compressors and receivers (one operating, one standby). Flow meters and valves shall be provided to
control recycle flow to each DAF stream.
The sludge blanket shall be removed either hydraulically or mechanically and shall be initiated
automatically after a preset (adjustable) time interval. Mechanical desludging is preferred so that sludge
can be sent directly to dewatering, avoiding the necessity of an intermediate clarification step. However,
if a hydraulic sludge removal system is provided, an intermediate clarification step shall be included and
shall be independent of the clarification step used for membrane filtration backwash treatment. During
desludging, the system shall have the ability to automatically spray service water on the DAF walls. DAF
sludge shall flow by gravity to the solids treatment area. Pumping to the solids treatment area may be
required for high solids concentrations.
The clarified water from DAF shall flow to the UF Feed Tank. Water from this tank shall also be used for
recycle flow to the DAF system, as described above. The tank shall be provided with level sensors for
process control. The UF system shall be a horizontal, pressurized, cartridge type. The Clean-In-Place
(CIP) and maintenance wash systems shall be independent, including pumps and necessary chemical
tanks. The UF system shall include an integrity testing system to ensure integrity of membrane fibers.
Three UF trains shall be furnished. Each train shall be designed for 50% capacity. Space shall be
allocated for two identical trains to be added in the future when the second power block is built. The
intent is to provide one spare train at all times. It is expected that the number of operating UF units will be
same as the number of operating SWRO units. Back washing/ chemically enhanced backwashing shall
be on a frequent-timed basis and not based on trans-membrane pressure. The contractor shall determine
the feasibility of using SWRO reject as potential source of UF backwash water.
The filtrate water from the UF system shall flow to the SWRO Feed Tank. Water from this tank shall be
used to feed the SWRO units as well as provide necessary water for UF backwashing. The tank shall be
equipped with level sensors.
Water from the SWRO Feed Tank shall be pumped through the cartridge filters to the suction side of the
high pressure SWRO Feed Pumps. The high pressure pumps shall be provided with a Variable
Frequency Drives (VFD).
The cartridge filters shall be sized to provide one spare and shall be connected to a common header.
Such an arrangement allows change of cartridge elements without having to shutdown the plant. The
cartridge filters shall be provided with differential pressure measurement. Cartridge filters shall be
disposal type and rated at 5 micron. Sodium bisulfite shall be added downstream of the cartridge filters
for dechlorinating feed water since RO membranes are sensitive to chlorine. Acid and antiscalant shall
be added upstream of the cartridge filters. Chlorine, ORP and pH monitoring devices shall be installed
downstream of cartridge filters, after allowing sufficient mixing of all chemicals added.
The effluent from the cartridge filters is pressurized by the High Pressure SWRO Feed Pumps. The water
is then treated by a single pass, single stage SWRO. The SWRO shall be comprised of 3 X 50% trains in
parallel. Provisions shall also be included for a future increase in capacity. The reject from the SWRO is
directed back to the ocean. The SWRO effluent feeds into the Service/ Fire Water Tank and/or the Fire
Water Tank.
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Materials of Construction
All materials shall be optimally selected to be compatible with the product flows as well as any chemical
additions taking place in close proximity of the piece of equipment in question.
Controls and Instrumentation
The facility is controlled locally by PLCs with supervisory control and monitoring available in the plant
DCS . The UF and SWRO processes shall have independent PLCs.
Acid addition shall be paced with the pH of clarified water based on the optimal pH required for
coagulation. Polymer addition, if required, shall be flow paced, based on a dose selected by the operator
through jar testing. Chlorine addition shall be flow paced, based on maintaining a chlorine residual up to
the cartridge filters and shall be operator selectable. Sodium bisulfite shall be added to achieve zero
chlorine residual. Antiscalant is flow paced, based on a dose selected by operator.
01630.4.6
Cycle Makeup Treatment (WTD)
Function
The Cycle Makeup Treatment system shall be comprised of two water treatment processes: Brackish
Water Reverse Osmosis (BWRO), and Electrodeionization (EDI). The function of the Cycle Makeup
Treatment system is to produce water of sufficient quantity and quality to satisfy all plant Deminiralized
water needs including HRSG makeup and NOx injection water.
Component Description
The Desalination system consists of the following major components and ancillary systems:





Brackish Water Reverse Osmosis (BWRO) equipment
Electrodeionization (EDI) equipment
Cartridge Filter equipment
Recycle Tank
Chemical Injection Systems
General description
The recycle tank shall act as a point of recovery for drain waters from the HRSG Blowdown Tanks,
Turbine Area Drains Tank, and ionized contaminants from Electrodeionization (EDI). The Recycle Tank
shall be sized to provide adequate storage capacity for the current combined cycle block as well as the
future combined cycle block of similar size. The tank should include enough storage to allow for cyclical
operation of the BWRO system while the plant is operating on natural gas. The tank vent shall be
designed to release any hydrogen that might become entrained in waste streams to the recycle tank.
The cycle makeup treatment system accepts feed water from the service/ fire water tank and/or the
recycle tank. The BWRO feed shall travel through cartridge filters, where any large particles are removed.
Reverse Osmosis Feed Pumps shall then feed the two-pass, two-stage Brackish Water Reverse Osmosis
(BWRO) process. This process shall be designed to minimize reject waters being sent to the Waste
Water Recycle Basin (WWRB). Upon entering the first pass, product water shall pass through to the RO
2nd Pass Feed Pumps and reject water shall enter the second stage. Caustic shall be fed between the RO
passes to facilitate carbonate removal. Product water from the second stage shall pass through to the RO
2nd Pass Feed Pumps, while any remaining rejects shall be sent to the Wastewater Recycle Basin
(WWC). The second pass of the BWRO system shall be of the same arrangement as described for the
first pass. Product water from the second pass shall enter the Reverse Osmosis Product Tank, while
reject water from the second pass shall be sent to the Wastewater Recycle Basin. The BWRO process
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shall be designed to supply sufficient flows to keep the plant in operation during regular cleaning and
maintenance intervals of the BWRO units.
Water from the RO Product Tank is pumped to the Electrodeionization (EDI) skids via the RO Product
Pumps. The Electrodeionization units shall continuously remove contaminant ions from the flow steam
while continuously being regenerating by way of an electrical current. Contaminant ion flow shall be sent
to the Recycle Tank while the Electrodeionization effluent shall be sent to the Demineralized Water
Storage Tank. The EDI process shall be designed to supply sufficient flows to keep the plant in operation
during regular cleaning and maintenance intervals of the EDI units. Mixed bed exchanger connections
shall be supplied downstream of the Electrodeionization units.
Materials of Construction
All materials shall be optimally selected to be compatible with the product flows as well as any chemical
additions taking place in close proximity of the piece of equipment in question.
Controls and Instrumentation
The facility is controlled locally by PLCs with supervisory control and monitoring available in the plant
DCS. The BWRO, and EDI processes shall have independent PLCs.
Sodium bisulfite shall be added to achieve zero chlorine residual. Antiscalant is flow paced, based on a
dose selected by the operator. Caustic shall be flow paced, based on a dose selected by the operator..
01630.4.7
Wastewater Collection and Treatment (WWC)
Function
The Wastewater Collection and Treatment System collects and conveys wastewater originating in the
plant to the Dissolved Air Floatation (DAF) Influent.
Major Components
The Wastewater Collection and Treatment System shall include the following major components:




One wastewater collection lift station with two full capacity wastewater transfer pumps sized
for the current 3x1 combined cycle block.
One wastewater recycle basin sized for both the current and the future combined cycle
blocks and with provisions for pumps for the future block.
Two full capacity wastewater recycle pumps sized for the current 3x1 combined cycle block.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
The wastewater collection and treatment system shall collect plant and equipment drains in the
wastewater collection lift station. Two full capacity wastewater transfer pumps (one operating, one
standby) shall pump the wastewater to the wastewater recycle basin. Two full capacity wastewater
recycle pumps (one operating, one standby) shall pump the wastewater from the wastewater recycle
basin to the DAF influent.
All vent, drain, and air user connections shall be furnished with a single valve for isolation.
Materials of Construction
Materials of construction shall be as follows:
Source: 01630, 2005
System Descriptions
Page 63 of 65
ESKOM COEGA CCGT
144807.71.0201
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WORKS INFORMATION
EMPLOYER REVIEW
20October06
Wastewater Pumps – Cast iron casings, carbon steel shafts, bronze impellers and shaft
sleeves.
Piping – Carbon steel ASTM A53 or A106 Gr. B seam welded.
Valves 2 inch (50 mm) and smaller – CL 600, socket weld, forged steel ASTM A105
Valves 2-1/2 inch (65 mm) and larger – Class 175 WWP, flanged, cast iron (ASTM A126
Class A or equivalent), with bronze trim (ASTM B61 or equivalent) (Gate and globe valves to
be OS&Y)
Controls and Instrumentation
Monitoring of the wastewater collection station and recycle basin levels shall be provided from the
Distributed Control System (DCS).
Alarms generated by the Wastewater Collection and Treatment System are annunciated in the control
room and displayed on the DCS operator interface stations.
01630.4.8
Oily Waste Drains (WWD)
Function
The Oily Waste Drains System collects and treats potentially oil-contaminated wastewater originating in
the plant and conveys the treated water to the waste water collection lift station.
Major Components
The Wastewater Collection and Treatment System shall include the following major components:
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One full capacity fire pump house submersible sump pump.
One full capacity fuel oil containment submersible sump pump per CTG and one for STG.
Two full capacity condensate trench submersible sump pumps.
Two 50 percent capacity stormwater submersible pumps.
One stormwater collection lift station.
One oil/water separator.
One oil analyzer.
Interconnecting piping, valves, instrumentation, and accessories.
General Description
Wastewater is collected from areas where there is potential for oil contamination. These wastes shall be
collected by floor drains, piping, trenches, and sumps which shall be routed to the stormwater collection
lift station. The stormwater collection lift station shall collect the wastewater and direct the water to the
inclined plate oil/water separator.
The inclined plate oil/water separator shall be above ground and remove oil contamination by utilizing the
specific gravity difference between water and oil. Discharge from the inclined plate oil/water separator
shall be routed to the waste water collection lift station. The oil shall be retained for eventual removal
and disposal offsite in accordance with the Employer’s regulations.
Oil and/or fire protection water shall be captured in the containment area and held there for disposal by
others. Containment sized to handle all oil plus 1 hour of fire protection water flow.
Materials of Construction
Source: 01630, 2005
System Descriptions
Page 64 of 65
ESKOM COEGA CCGT
144807.71.0201
WORKS INFORMATION
EMPLOYER REVIEW
20October06
Materials of construction shall be as follows:
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


Oily waste drains collection and treatment pumps – Cast iron casings, carbon steel shafts,
bronze impellers and shaft sleeves.
Piping – Carbon steel ASTM A53 or A106 Gr. B seam welded.
Valves 2 inch and smaller – CL 600, socket weld, forged steel ASTM A105
Valves 2-1/2 inch and larger – Class 175 WWP, flanged, cast iron (ASTM A126 Class A or
equivalent), with bronze trim (ASTM B61 or equivalent), (Gate and globe valves to be OS&Y)
Controls and Instrumentation
Monitoring of the Oily Waste Drains System sump levels shall be provided by the Distributed Control
System (DCS).
Alarms generated by the Oily Waste Drains System shall be annunciated in the control room and
displayed on the DCS operator interface stations.
Source: 01630, 2005
System Descriptions
Page 65 of 65