CITY OF PALO ALTO
Utilities Department
SPECIFICATION FOR
15KV, 600/200 AMP, DEADFRONT,
OIL-INSULATED, PADMOUNTED VACUUM SWITCHGEAR
WITH VACUUM FAULT INTERRUPTER
1.
SCOPE
This specification details the requirements for three-phase, 60 Hz, fully deadfront,
sectionalizing padmounted switchgear with maximum ratings of 600 amperes
continuous current, maximum tap rating of 600 amperes. Tap overcurrent protection
shall be accomplished utilizing a resettable vacuum fault interrupter (VFI) which shall
be provided with three-phase three-pole ganged operation. Unit is to be of oilinsulated sealed tank design, so operation is unimpaired by flood conditions or
contaminated environments. All current interruption shall be accomplished utilizing
vacuum switches or vacuum fault interrupters having load and fault break capabilities
as appropriate. The switchgear is to be used on a 15KV rated (operated at 12,470
volts), three- phase, 60 Hertz, grounded neutral, underground distribution system.
2.
GENERAL
Unit shall be single sided compact design with side hinged doors for installation on a
concrete pad at ground level. Switchgear must be in complete conformance with the
latest revisions of industry standards for manually operated, deadfront padmounted
switchgear with load interrupting switches and separable connectors for alternating
current power distribution systems. In general, the bidder shall agree to furnish
padmounted switchgear(s) ready for service, manufactured and tested according to the
latest applicable standards of American National Standards Institute (e.g. ANSI
C37.72, C37.90, C57/37), Institute of Electrical and Electronics Engineers (e.g. IEEE
386), American Society for Testing and Materials (e.g. ASTM D-2472-71), National
Electrical Manufacturers Association (NEMA), and Institute of Electro-technical
Commission (e.g. IEC 265).
The vacuum fault interrupter shall meet the full-life duty cycle specified by ANSI
C37.60 with additional requirements as stated in this specification. The electronic trip
control shall meet the requirements of ANSI C37.90, ANSI C37.90.2,
IEC 801-3, and IEC 68-2-30.
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August 21, 2001
The complete assembly will be produced by a single manufacturer that will also be
totally responsible for the performance of the final product. The switchgear shall be
furnished factory assembled, tested and oil filled. Upon City's request, the
manufacturer shall provide 72 hours notice to allow City representatives to witness
any test performed on the switchgear. Opportunity for in-plant observation shall be
provided for the City at any time during the manufacturing process.
3.
4.
DEVIATION AND NON-CONFORMANCE REQUIREMENT
A.
Omission or error in these or the manufacturer's specifications of an item of
material or equipment necessary for the operation and matching of the offered
equipment in conjunction with the other equipment, existing and future, shall
not excuse the bidder from responsibility in this matter.
B.
Deviation from these specifications or changes in the material or design after
purchase order has been placed must be approved by the City's Electrical
Engineering Manager or his designated representative, and acknowledged by
an addendum to the specification which shall be issued as a Purchase Order.
C.
Units received with deviations or changes which are not approved or
acknowledged by the City's Electrical Engineering Manager, or his designated
representative are subject to rejection. The supplier of units rejected is
responsible for any corrective action including but not limited to materials,
labor and transportation necessary to make the units conform to these
specifications.
D.
Units with defects, discovered before or after installation, that are believed to
be inherent to manufacturing problems or workmanship shall be rejected and
supplier shall be responsible for correcting the defect or replacing the unit
without additional equipment or freight charges to the City.
INSTRUCTION TO BIDDERS
A.
The bidder shall submit the proposal in accordance with the City's Request for
Proposal (RFP) issued by the City’s Purchasing/Contracts Departments.
B.
The bidder shall supply proposal information that shall include the complete
design and construction details and is truly representative of any equipment to
be furnished.
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August 21, 2001
5.
C.
Any exceptions to be taken by the bidder to these specifications shall be set
forth clearly by typewritten attachment by the bidder in his/her proposal.
D.
The successful bidder shall submit all drawings and diagrams in complying
with the specifications to the City for approval within ten (10) weeks after each
approved order. The bidder's schedule shall include the time for transmittal of
drawings for approval in addition to a minimum of ten (10) working days for
review by the City. Revisions of the drawings to make them comply with the
specifications shall be at the bidder's expense and without extension of the
completion date.
E.
Each drawing supplied by the bidder shall bear identification showing the
City's purchase order number, date of the drawing release, and whether the
drawing is for approval or approved for construction.
F.
Shipping and storage shall be accomplished in such a manner as to prevent
damage or deterioration of materials.
RATINGS
The rating of the entire switchgear assembly shall be as follows:
a)
b)
c)
d)
e)
f)
g)
h)
i)
j)
k)
l)
m)
n)
o)
p)
Nominal phase-to-phase voltage:
Maximum rated design voltage:
BIL impulse withstand:
One minute AC withstand @ 60HZ:
Continuous and load interrupting current (Max):
Momentary Current rating
3 Second (Symmetrical)
10 Cycles (Asymmetrical)
Number of mechanical operations (min.) for each
Switch or VFI including vacuum bottle:
Number of operations (min.) at full load:
Max. Interrupting current (Sym/Asym):
Min. partial discharge corona extinction voltage:
Cable charging interrupting current:
Capacitive Current:
Magnetizing interrupting current:
Load Switching:
DC 15 minute withstand:
Ambient temperature range
Page 3 of 25
15KV
15.5KV
95KV
35KV, RMS
600 AMPS.
12 KA, RMS
20 KA, RMS
10,000
2,000
12/20 KA
11KV, RMS
10 AMPS, RMS.
10 AMPS, RMS
21 AMPS, RMS
600 AMPS.
53KV
-30 to +40° C
August 21, 2001
6.
TRIP CONTROL
A. Standard Electronic Control: Overcurrent sensing shall be accomplished with an
electronic trip control that shall provide three-phase and ground overcurrent protection.
The control shall use internally mounted bushing current transformers to sense line
currents. These CT’s shall also provide power for control operation. No external power
source shall be required. To provide immunity from system voltage problems (i.e.
overvoltage transients) the control shall not be sensitive to system voltage conditions.
The control shall be fully operable and meet the specified time-current curve immediately
upon energization. No “warm-up”, initialization, or arming time delays adjustments shall
be necessary. No minimum load requirement or battery back-up device shall be
necessary to meet the specified time-current characteristics. The control shall have a
minimum operating temperature range of - 40° C to +65° C with no more than a ±5%
variation in time-current response characteristics from its response at +25° C.
The standard control shall provide minimum phase overcurrent trip settings that are
field selectable (in 10 amp increments) over a range of at least 20 amps to 1300 amps.
Trip settings may be changed while the switchgear is energized (so service is not
interrupted). An instantaneous trip feature shall be provided as a standard feature of
the control. Phase and ground instantaneous trip shall be field selectable over a range
of at least 1X to 15X times the phase and ground overcurrent trip settings or it may be
selected to be disabled. The instantaneous trip feature shall provide a fixed 0.025
second response time characteristic.
A single time-current curve shall be provided that is common to all three phases.
Time-current trip curves shall be changeable by plug-in modules or programmable
controls. The standard time-current curve provided shall be extremely inverse and
shall emulate the time-current characteristics of a standard speed E-rated power fuse.
If specified, an alternate curve shall be provided. Additionally, when requested, a
minimum response time feature shall also be available as an alternate version of the
tcc plug-in modules. This feature shall allow field selection of a minimum allowable
trip response time for the control, if required. The available minimum response time
settings shall be in the range of 0.05 to 0.60 seconds or greater.
The control shall provide ganged tripping of the vacuum fault interrupters on each
phase of the protected tap. This shall be a standard feature and shall be selectable via
a dip switch located on the control circuit board. If the specified switchgear is to
have one or more VFI taps that are three phase trip only, it shall be provided with a
single operating handle to operate all three phases on those taps, with the tripping
mechanisms of each phase mechanically linked together, and the control(s) shall have
Page 4 of 25
August 21, 2001
the dip switch set in the ganged trip position. The control and its enclosure shall be
mounted on the inside of the cabinet door. The control enclosure shall provide
protection against rain equivalent to a NEMA Type 3R.
Provision for shorting of all CT’s shall be provided. The switch shall allow the
operator to easily de-energize the control for maintenance or disable the control from
sensing and tripping on overcurrents.
B. Alternate Control (Vacuum Circuit Breaker Control): Three-phase and ground
overcurrent relays shall be provided. Overcurrent relays shall be of the solid state drawout type such that the elements can be removed, tested and calibrated with conventional
switchgear relay test equipment. The relay shall be capable of tripping the breaker
manually by pushing a manual trip button when the trip device is energized. The solid
state overcurrent relays shall be designed to match the typical time-current characteristic
curves of convention induction disk overcurrent relays for easy coordination with
upstream and downstream electro-mechanical relays and fuses. Relays shall have a very
inverse or extremely inverse time-current curve, to be selected by the City when
equipment is ordered. Solid state overcurrent relays shall be operated from standard
current transformers with 5 amperes secondary current. The tripping solenoid shall be
activated by a solid state overcurrent relay which has the output of the bushing mounted
current transformer fed into it. Stored energy for powering the relays and solenoid shall
come from a capacitor trip device fed through diodes arranged such that any diodes can
fail by opening or shorting without causing system failure. Capacitor charging voltage
shall be provided by a fused potential transformer connected to the switchgear bus on the
source side of the circuit breaker. The fuse for the potential transformer shall be
externally accessible when switchgear door is open.
Note, the bidder may propose a different type of relay controls as an alternate (e.g.
Schweitzer Relays); however, the bidder shall provide price for above option.
7.
SWITCHES
Switches shall utilize vacuum interruption only. Switches shall be three-phase gangoperated vacuum switches that meet or exceed the performance requirements of ANSI
C37.72. The mechanism and the vacuum interrupters employed shall be capable of
interrupting the rated continuous current and fault currents up to 12-kA symmetric.
The switch shall have a single operating handle, designed for operation with a
lineman’s hotstick, that has a push to close / pull to open operation requiring no more
than 75 lbs. of force at the handle and 60 degrees of movement for complete
operation. Switch operating handles shall be front plate mounted and shall be
padlockable in both the open and closed positions. Mounting provisions for Kirk key
Page 5 of 25
August 21, 2001
interlocks shall be provided as a standard feature. If specified, operations counter
shall be supplied that is externally mounted on the frontplate of the switchgear and
mechanically linked to the operating handle.
8.
VACUUM FAULT INTERRUPTERS
The switchgear shall incorporate vacuum fault interrupters for tap overcurrent
Protection as specified. The device shall interrupt all fault currents up to the
rated maximum. The interrupter shall be manually resettable, with no consumable
parts (i.e. fuses). The maximum interrupting time from issuance of a trip signal
from the electronic control shall be 2 cycles.
To provide maximum safety to the operator, the interrupter shall incorporate a trip-free
mechanism to prevent the possibility of holding the interrupter closed under a faulted
condition.
Since three-phase trip operation is specified, the vacuum fault interrupter shall act as a
three-phase group operated circuit breaker. The trip mechanisms for each phase shall be
mechanically linked and the electronic control shall be set so that an overcurrent
condition on any one phase shall simultaneously trip all three phases. A single operating
handle shall be provided for manual opening, reset and closing. The operating handle
shall be mounted on the frontplate of the tank in the tap compartment and shall have three
distinct operating positions corresponding to whether the vacuum fault interrupter is
open, closed, or tripped or alternatively, open, closed, with a yellow trip indicator which
is reset by moving handle to the open position. A pointer attached to the handle along
with a decal shall be provided for ready identification of the handle position. The handle
shall be designed for operation with a lineman’s hotstick and have a push to close/pull to
open/pull to reset operation requiring no more than 75 lbs. of force at the handle and 60
degrees of movement for complete operation. When the vacuum fault interrupter is
tripped the operating handle shall drop to an intermediate position between its closed and
open positions, to indicate that it is tripped. The operating handle assembly shall include
provisions to padlock the handle in the open position. If specified, operations counter
shall be supplied that is externally mounted on the front plate of the switchgear and
mechanically linked to the vacuum fault interrupter operating handle.
9.
BUSHINGS
All switchgear shall be designed to interface with deadfront terminations as defined in
ANSI/IEEE 386 and ANSI C119.2. The bushings shall have a continuous rating of
600 Amperes or 200 Amperes as specified. The switchgear shall contain approved
manufacturers' 600-amp bushing with aluminum conducting parts to mate with the
Page 6 of 25
August 21, 2001
aluminum parts of the cable terminations to be used. There shall be one parking stand
bracket next to each bushing well. The switch bushings shall be identified and legibly
marked adjacent to each bushing with the appropriate phase designation, using a
nameplate of stainless steel or other corrosion resistant material. Bushing shall be
diagonally mounted to allow for single sided compact design with side hinged doors.
The bottom bushings (C-phase bushing) shall be 18” minimum from the bottom of the
enclosure. The 600-amp bushings shall be RTE insulated deadbreak type and the
200-amp sources and taps shall be furnished with RTE 200-amp load break bushing
wells. Alternatively, the 600-amp and 200-amp bushings can be elastimold welded in
type to provide 30 year life without gasket deterioration. All bushing wells shall
conform to ANSI/IEEE 386 and ANSI C119.2. Bushings shall be externally replaceable
and shall not require removal of the tank core to remove or install replacement bushings.
10.
CABLE TERMINATIONS
1. Cable terminations on the VFI shall be by means of appropriately rated separable
connectors.
2. For 600-amp connections, manufacturer shall provide 3 one-piece bushings per way
capable of accepting 600-amp dead break connectors meeting requirements of
ANSI/IEEE 386. Each bushing shall be equipped with a protective cover, and placed
to maintain no less than 5 inch centers and no greater than 8-inch centers.
3. For 200-amp connections, the manufacturer shall provide bushing wells meeting the
requirements of the latest revision of ANSI/IEEE 386 for separable connectors. Each well
shall be equipped with a protective cover and placed to maintain no greater than 8-inch
centers and no less than 5-inch centers.
11.
BUS
All bus shall be of copper. Bus wrapped with organic material will not be permitted.
12.
INSULATION
All energized parts shall be insulated and completely enclosed with a grounded shield
system when separable connectors are in place. Switches and busbars shall utilize oil
as the insulating medium to minimize the size of the unit. The oil shall contain less
than 1ppm PCB. The oil shall be classified as Non-PCB per California standards.
There shall be a “Non-PCB” label with 1/2 inch or larger block letters affixed to the
inside termination compartment. The nameplate on each switchgear shall specific the
type of oil installed in the switchgear and that it contains less than 1 ppm PCB’s.
Page 7 of 25
August 21, 2001
13.
OPTIONAL FEATURES
When specified, the one or more of the following optional features shall be provided:
A.
SCADA OPTION
If specified, a SCADA / Accessory board shall be provided that is mounted within the
same control cabinet assembly. This accessory shall include its own battery backup,
to be provided long life lithium batteries, as required to support proper activation of
the inrush restraint feature upon power up from a de-energized state. This accessory
shall provide:
1. A minimum trip multiplier feature that shall activated by a separate toggle switch
located within the control housing. This feature shall allow normal minimum trip
levels for each phase and ground to be raised from 1.1X to 13.7X their normal setting
while this feature is active. This multiplier shall be field selectable and shall be
independently settable for each phase and for ground. A contact output shall be
supplied for remote status indication.
2. An inrush restraint feature that shall allow the control to automatically raise the set
minimum trip levels for phase and ground to a field selectable multiple of 1X to 32X,
in increments of 1X, for a selectable time interval of 0.5 to 32 seconds, in increments
of 0.5 seconds. The feature shall also have the field selectable provision to block
ground trip during the interval that the inrush restraint is active.
3. A remote trip feature that can be activated by the momentary closure of dry
contacts when a minimum of 3 amps line current is present on any phase or, if not,
will allow trip of the VFI if a wetting voltage is supplied in addition to the dry
contacts. This feature shall allow selection of either 120Vac/125Vdc, 48Vdc, or
24Vdc as the user supplied wetting voltage, selectable by a slide switch.
4. Trip indication targets shall be provided on the circuit board with separate targets
for each phase and ground. After a trip event, these targets shall give visual indication
where the fault occurred. The phase target shall reset after restoration of line current
in the affected phase. The ground target shall reset after restoration of current in any
phase. Contacts for remote indication of a trip event shall be provided for each phase
and ground.
5. A separate ground trip toggle switch shall be provided within the control enclosure
to allow easy activation of the ground trip when a known phase unbalance condition
Page 8 of 25
August 21, 2001
will be created due to switching or maintenance operations that may cause an
unwanted ground trip. A contact shall be provided for remote status indication of the
switch.
6. A contact shall be provided for remote status indication of the CT shorting switch.
B.
OPEN/CLOSED SEMAPHORES
When specified, an optional Open/Closed semaphore shall be provided which shall
serve the purpose of giving a second confirming indication of the open or closed state
of the source vacuum switches and/or the tap vacuum fault interrupters. The
semaphore shall be mounted internally and shall be directly linked to the movable
contact rod of the vacuum switch and/or vacuum fault interrupter. The semaphore
shall be visible through a viewing window on the tank frontplate near to the operating
handle for the vacuum fault interrupter.
C.
AUXILIARY SWITCHES
When specified, the source vacuum switches shall be provided with two “a” and two
“b” auxiliary switches for the purpose of remote indication of switch status or other
customer use. The auxiliary switches shall be linked to the movable contact rod of
the vacuum switch and shall be internally pre-wired to a MIL C-5015 style circular
power connector receptacle that is mounted on the source frontplate. The receptacle
shall be provided with a mating plug for customer installation and termination of their
cable. The auxiliary switches shall be rated for 15-amps @ 120-Vac / 1-amp @
125-Vdc.
D.
MOTOR OPERATOR MOUNTING PROVISIONS
When specified, the source vacuum switches and/or three-phase gang-operated VFI
taps shall be provided with mounting provisions for future addition of motor operators.
The provisions shall include auxiliary switches with one “a” and one “b” contact,
mounting studs for motor operator mounting brackets, switch operating handles with
provision for attachment to motor operators, studs and channels for routing cable
connections to the future motor operator control, stud mounting provisions on the
inside of one of the cabinet doors (standard location) for the future motor control, and
a minimum of a 30-inch deep cabinet that shall have side-hinged doors. If the
switchgear is to be self-powered, an internal 1.5KVA rated single-phase potential
transformer (oil-insulated designs only) shall be provided that shall be connected to
the A-phase of the common bus and protected against failure of the potential
transformer by an under-oil primary current-limiting fuse. The transformer primary
Page 9 of 25
August 21, 2001
shall be rated for the system line to ground voltage and provide a 120-Vac secondary
voltage output. Primary and secondary connections shall be grounded wye with an
internal ground lug connection that is attached to the switchgear tank. The potential
transformer shall be wired to the MIL C-5015 style connector that is provided for the
auxiliary switch connections.
When motor operator provisions are specified for a vacuum fault interrupter tap, an
Open/Closed semaphore shall be provided to indicate the actual status of the vacuum
fault interrupter under the condition that the motor actuator is holding the operating
handle in the closed position.
Alternately, a separate cabinet may be specified, that shall be mounted on the side of
the switchgear tank and shall allow location of the control in an enclosure that is
separate from the high voltage cable entrance.
E.
MOTOR OPERATORS
When specified, dc motor operators and a single dc motor control shall be supplied for
the source vacuum switches and/or any three-phase group operated VFI taps. The unit
shall include all standard motor operator mounting provisions specified in section 6.3.
Optional provisions, such as an internal potential transformer for power supply to the
motor control, shall be supplied on when specified as a requirement for an oilinsulated unit.
The motor operators shall utilize 24-Vdc motor actuators to open and close their
respective switch or VFI. The average time required to open or close a switch or VFI
shall be 5 seconds. The motor control shall be equipped with a 2.5 amp-hour sealed
lead acid gel-cell battery that supplies the energy to activate the motor operators and all
control functions. The battery shall be capable of providing a minimum of 25 open and
25 close operations, without an ac supply voltage present, before recharge is required.
Battery charge shall be maintained by a temperature/voltage regulated charger within
the motor control, which shall be capable of fully re-charging a low battery within 24
hours. Nominal battery life shall be six years before replacement is required.
The motor control shall utilize a customer supplied 120-Vac two-wire supply. The
control shall also have provisions for accepting a second, alternate 120-Vac supply and
shall provide a transfer relay to transfer to the alternate supply if the primary 120-Vac
supply is lost. If an internal potential transformer for power supply to the motor control
has been specified, the unit shall be provided with all necessary wiring factory installed.
The motor control shall include the following features:
Page 10 of 25
August 21, 2001
1. The motor control shall be capable of operating up to six motor actuators, one at a
time. A selector switch shall be provided on the control panel to select the motor
actuator that is to be operated.
2. Open, Close, and Stop pushbuttons shall be provided for operation of the selected
motor actuator.
3. Open and Closed indicating lights shall be provided to indicate current status of the
selected switch or VFI. These status lights shall use auxiliary switch inputs from
the source vacuum switch or VFI to determine actual open or closed status.
Opening and closing indicating lights shall be provided to verify that the selected
motor actuator is in process of opening or closing a switch. A lamp test pushbutton
shall be provided to confirm that indicating lights are functional. The indicating
lights shall utilize high intensity LED’s for long life.
4. A Power On/Off toggle switch shall be provided that shall disconnect the dc
voltage supply from the control and any selected motor actuators and shall
function as a dc circuit breaker to interrupt the dc supply in the event of a short
circuit or overload.
5. An LED indicator shall be provided to verify that 120-Vac power is present and
that the battery charging circuit is providing a charging voltage to the battery. A
battery test pushbutton shall be supplied with test points to apply a voltmeter for
testing the condition of the battery.
6. A Local/Remote toggle switch shall be provided. In the Local position, the switch
shall allow operation of the motor actuators by the pushbuttons on the control
panel only and shall not allow remote or SCADA operation. In the Remote
position, the switch shall allow both local and remote or SCADA operation of the
motor actuators.
7. The control shall include a terminal strip for connection to SCADA or remote
control equipment. The terminal strip shall have connections for selecting a
motor actuator with a maintained dry contact input, reading the Open/Closed
status of the associated switch or VFI, initiating a Open or Close operation via
a momentary dry contact, and reading the Opening/Closing status of the
motor actuator as it performs the required operation.
8. The control shall also include, when specified, provisions to add a hand-held
extended control accessory and an interconnecting cable (length to be specified,
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August 21, 2001
maximum is 200 ft.). This accessory shall provide the same motor selection and
operating pushbuttons as the main control that is mounted with the switchgear so
as to temporarily allow operation of the motor actuators from a more remote and
convenient location.
14.
PERFORMANCE REQUIREMENTS
1. Switchgear shall be used to perform sectionalizing on underground distribution
systems with routine operations that include:
a. Parallel two sources and interrupt loop flow.
b. Energize cable, transformers and connected loads capacitor banks, including
duties of inrush, cold load pickup and fault closing.
c. Interrupt load current or magnetizing current.
2. The switchgear shall be designed for a useful life of at least 30 years.
15.
CONSTRUCTION
1. The padmounted VFI shall consist of a sealed insulated tank and a separate front
main and tap compartment. Overall height, width and depth layout shall conform to
the manufacturer’s standard construction practices for the configuration, rating, and
voltage class specified.
2. Units shall be shipped complete with oil. Oil insulated units shall be equipped with
a 1-inch oil fill plug and 1-inch drain plug with sampler. Oil drain valve with sampler
shall be provided. Both the source and tap side of the switchgear shall have an oil
level indicator sight glass. A single automatic pressure relief valve shall be supplied
that is hotstick operable and located on the source side frontplate above the oil level
within the switchgear.
3. The switchgear cabinet shall be constructed to provide adequate space, volume
and strength for cabling, and shall withstand all pressure build-up during interruption
without permanent distortion or damage to any portion of the structure. The cable
compartment shall have a minimum depth of 27 inches.
4. Unless otherwise specified, the low profile padmount enclosure shall have the
following dimensions:
Maximum Depth (in.)
Maximum Width (in.)
Page 12 of 25
----------------- 62
----------------- 64
August 21, 2001
Maximum Height (in.)
Minimum Depth Tank to Door (in.)
----------------- 54
----------------- 27 or 24 if control box
is mounted inside cabinet door
5. Access to the fault interrupting switchgear unit for maintenance and cable
terminations shall be through a hinged front split door to allow easy operation by one
person.
6. Door hinges shall be provided with stainless steel pins.
7. Door shall be equipped with a positive latching device to prevent unintentional
closing (e.g. wind blowing).
8. Door shall be secured with recessed, pentahead bolts with provisions for
padlocking. Switchgear shall be lockable by means of a standard CPA padlock that
has a 3/8" diameter shank.
9. Door shall be constructed using 11 gauge minimum stainless steel or steel.
10. The fault interrupting switchgear compartment and compartment base shall be
constructed using 11 gauge minimum stainless steel or steel.
11. The switchgear liquid filled tank shall be constructed of 7 gauge minimum
stainless steel or steel.
12. Parking stand brackets shall be provided to allow for easy cable isolation during
maintenance on all 600 and 200 Amp switch positions. Parking stands shall accept all
standard elbow accessories for grounding, testing and isolating cable connections.
13. The enclosure shall have lifting lugs of adequate strength and size at each corner
to provide for easy balanced handling and installation of the completely assembled
unit. A 1-1/2 inch, internal flange shall be provided at the base corner of the switch
compartment to provide means for anchoring the switchgear unit to the pad.
14. Top of fault interrupting switchgear enclosure shall have a positive crown to
prevent water from being trapped.
15. All external hardware and accessories shall be stainless steel or other approved
corrosion-resistant material. All nuts, bolts, and washers shall be stainless steel.
Page 13 of 25
August 21, 2001
16. A detailed set of instructions for the installation, operation, and maintenance of the
fault interrupting switchgear and associated parts shall be secured in a weather proof
pouch inside the unit's doors.
17. Enclosure shall be coated with an acceptable corrosion resistant finish conforming
to ANSI C57/C37 and EEI, to avoid a reduction in the service life of the equipment.
To blend in with the landscape and provide a pleasing appearance, external switchgear
compartment shall be painted padmount green (Munsell Green No. 7GY 3.29/1.5,
Keeler & Long P-2-9750, PG&E 610, Sherwin Williams F88 XXG 8692-4394,
Sherwin Williams F36 HXG 137-4386, or Plascron Waterborne Coatings, or approved
equal). All surfaces shall be cleaned of all dirt, rust, moisture and lubricants and
primed prior to painting. The interior of the terminal compartment; if not stainless
steel; shall be painted same as the external coating. Tank internal coating shall be
moisture resistant. Paint shall be uniform and even, free of runs, sags, checks or
blisters. The coating system shall meet or exceed ANSI C57.12.28 (Coating system
requirements for padmounted equipment).
18. The entire bottom surface of the unit; if not stainless steel; shall be undercoated
with a suitable undercoating.
19. External construction shall be such that there are no sharp or jagged edges that
may cut, scrape or injure. To minimize possible injury to the public, corners shall be
blunted.
20. A nameplate made of etched stainless steel shall be permanently affixed inside the
primary compartment of the fault interrupting switchgear with all letters, and numbers
engraved on the nameplate. The nameplate shall contain the following:
- The words "Vacuum Fault Interrupter"
- Manufacturer and address
- Manufacturer catalog number and serial number
- Model or style number
- Date of manufacturer (month and year)
- Serial number
- Continuous current rating
- Load break current rating
- VFI Interrupting capacity
- Momentary current and make and latch rating
- Nominal kV rating
- CT Ratio
- PT fuse voltage rating
Page 14 of 25
August 21, 2001
- BIL rating
- Total weight of entire switchgear
- Oil volume (gals.)
- Phase identification to clearly identify electrical connections as to whether it
is phase A, B, or C
- Three line diagram illustrating the switch configuration.
21. A non-corrosive operating circuit diagram (one-line schematic) shall be affixed to
the inside of the door, on both side of the unit depicting the internal electrical
configuration of the fault-interrupting switch. Nameplate and circuit diagram shall be
readily identifiable at a distance of 12 feet.
22. Permanent markings shall be provided at the switch operator to indicate switch
position.
23. Each switch terminal and each compartment ground terminal shall have a
grounding rod for attaching temporary, as well as permanent ground during cable
maintenance. These rods shall be capable of carrying the fault duty of the switchgear
and shall be located in such a manner that the clamps may be readily applied or
removed with a "hot-stick."
24. Switches shall be equipped with 5/16” holes for future installation of fault
indicator LED sensors by the City. The LED holes should be placed where they are
most easily viewed during a line patrol, but should not interfere with normal operating
procedures. There shall be a hole for each switch. Holes shall be located in the
removable sill under the switchgear access door. Apply a square reflective white
decal around the hole to improve visibility. The holes shall be capped with removable
plugs.
25. Switchgear connection configuration shall be designated on the purchase order.
Switchgear connection configuration shall include the types shown in the following
Table 1 below:
Table 1
Switch
Configuration
3-Way, 3-Switch
600 Amps.
Switch
2
600 Amps
VFI
1
1
2
200 Amps.
Switch
Page 15 of 25
200 Amps
VFI
One-Line
Schematic
Required
Required
August 21, 2001
3-Way, 3Switch
(4Pole, with 200A
Neutral Bushing)
4-Way, 4-Switch
4-Way, 4Switch
(4Pole, with 200A
Neutral Bushing)
2
1
Required
1
2
Required
2
1
Required
1
2
Required
2
1
Required
1
2
Required
2
1
Required
1
2
Required
2
1
Required
1
2
Required
3
1
Required
2
2
Required
3
1
Required
2
2
Required
3
1
Required
2
2
Required
3
1
Required
2
2
Required
3
1
Page 16 of 25
Required
August 21, 2001
2
5-Way, 5-Switch
16.
2
Required
3
1
Required
2
2
Required
4
1
Required
3
2
Required
2
3
Required
4
1
Required
3
2
Required
2
3
Required
4
1
Required
3
2
Required
2
3
Required
OPERATING FEATURES
1. The switch mechanism shall be designed so that operation of the fault interrupting
switchgear does not require any special skills and the closing and opening speeds of
the contacts are independent of the speeds at which the operating handle is operated.
2. The switchgear shall be equipped with an internal operating mechanism design so
that the speed of opening and closing the interrupter contacts will be independent of
the external operator. All contacts of the three phases shall be operated
simultaneously with no possibility of single phasing due to teasing of switch handle.
3. The switch shall be quick-make quick-break type. Contacts shall be stable in open
and closed positions without use of mechanical latches.
Page 17 of 25
August 21, 2001
4. Operating mechanisms shall be constructed to allow safe operation of the switch by
one person using a conventional shotgun stick and requiring no more than 75 pounds
of force to open or close the switches.
5. Provisions shall be made for determining safe insulating levels while the switch is
energized. A suitable liquid level gauge shall indicate the correct oil level at 25
degrees Celsius. Each switchgear shall contain a Low Insulation Level indication
device that shall have no moving parts and shall display “LOW OIL” with white
letters against a red background when insulation falls below safe levels.
6. Provisions shall be made to facilitate replacement of the insulating medium with the
padmounted fault interrupting switchgear de-energized.
7. Provisions shall be made for adding the insulating liquid with the switch energized.
8. Each switchgear shall include an upper oil filler plug.
9. All switchgears shall be equipped with a brass or stainless pressure relief valve
located above normal oil level.
17.
TESTING REQUIREMENTS
All switchgear shall be completely tested in accordance with the latest revisions of
NEMA and ANSI standards and must meet the manufacturer's performance guarantee
within the prescribed tolerances. Manufacturer shall maintain adequate and reliable
test records of the units tested. Copies of all relevant test reports pertaining to the
swithcgear shall be submitted to the City of Palo Alto with each shipment for its
records at no additional cost.
The following routine tests shall be made on all switchgear in accordance with the
latest revisions of ANSI C37.72 and ANSI C37.20
Descriptive information shall be furnished together with performance data on each
switchgear with the bid proposal.
It shall be expressly understood that these performance specifications, as furnished by
the successful bidder, shall constitute guarantees, with variance only as allowable by
applicable NEMA, ANSI and IEEE tolerances.
17.1
Production Testing:
Page 18 of 25
August 21, 2001
The unit shall be subjected to the following production tests:
1.
2.
3.
4.
5.
6.
17.2
Continuity tests to assure correct internal connections.
Hi-pot test to determine dielectric strength of the unit, test shall be
performed at 35kV or higher for at least one minute.
Pressure test to assure tank is completely sealed.
Electrical TCC trip test of electronic control or relays.
Micro ohm across each pair of bushings on each phase of the HV bus
Primary current injection test to ensure proper functioning of CT’s and
secondary wiring by proving the interrupters trip for an overcurrent
condition.
Other Electrical Tests:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Load switching tests
Magnetizing current tests
Cable charging test
Momentary current test
Making current test
Mechanical operation test
Impulse withstand (BIL) tests
Continuous current tests
Partial discharge level test
DC withstand test
One-second current test
Pressure test
All tests specified shall conform to procedures and circuit connections as specified in
ANSI Standard C37.72. The switch shall pass each of these in succession and shall
not be maintained between tests.
17.3
Finish Performance Test:
Switchgear shall be painted green conforming to (Munsell Green No. 7GY 3.29/1.5,
Keeler & Long P-2-9750, PG&E 610, Sherwin Williams F88 XXG 8692-4394, Sherwin
Williams F36 HXG 137-4386, or Plascron Waterborne Coatings, or approved equal)
padmount green. The coating must pass the following performance tests, which meet or
exceed ANSI C37.20.2 and C57.12.28 finishing guidelines for padmounted equipment:
a.
b.
2000 hour 5% spray corrosion test per ASTM B117-54
2000 hour humidity test per ASTM D2247
Page 19 of 25
August 21, 2001
c.
d.
500 hour ultraviolet accelerated weathering test ASTM G53/D523.
Impact with 160 in-lb. Falling dart per ASTM D2794
Certified test data shall be furnished upon request.
17.4.
Vandal Resistance Test
Vandal resistance tests shall comply with ANSI/IEEE 37.20.2 and the Western
Underground Guide 2.13, "Security for Padmounted Equipment Enclosures". The
switchgear shall be equipped for anchoring on a pad without additional housing, fences,
or other provisions to make the unit safe. This requires meeting the following tests:
a.
Inward axial force test: 50 lbs.
b.
Prying leverage tests: 75ft-lbs.
c.
Pull test: 150 lbs.
d.
Probe test: 14 AWG solid soft drawn copper wire.
Certified test data shall be furnished upon request.
17.5
Test Data:
Certified test data bearing the seal of a Registered Professional Engineer shall be
available upon request for the following:
1.
2.
3.
18.
Switch ratings per ANSI C37.72.
Interrupter ratings per ANSI C37.60.
Coatings per ANSI C57.12.28.
PREPARING EQUIPMENT FOR EARTHQUAKES
The design of equipment and its anchors to the foundation shall satisfy the minimum
equivalent static seismic load 0.5g horizontally in any direction, and +/- 0.4g
vertically, occurring simultaneously with horizontal load. Allowable working stresses
shall be used with 1/3 increase in allowed for seismic loading.
All anchor attachments shall be located outside of the cabinet with minimum one inch
horizontal clearance from the face of the wall panel and minimum eighteen inches in
vertical clearance above the base plate for the access of a rotary hammer. There shall
be a minimum of four anchor attachments.
Page 20 of 25
August 21, 2001
The minimum size of the anchor bolt to be specified in the design is 1/2" diameter
PARABOND capsule anchor by Molly Fastener Group or approved equal on 4,000 psi
ultimate strength concrete at 28 days.
Seismic calculations with outline drawings shall be prepared and certified by a
Professional Civil/Structural Engineer registered in the State of California and
submitted for approval before the commencement of fabrication.
19.
20.
DELIVERY
1.
The successful bidder shall deliver the switchgear by the date specified in each
order. The successful bidder shall notify the City in writing when change in
delivery is anticipated.
If at any time the City has reasonable cause to believe that the delivery will not
be made at the time and place specified, the City shall have the right to
terminate the purchase order, but shall not be obligated to do so.
2.
Switchgear delivered by truck shall be properly secured to the truck bed to
prevent damage in transit.
3.
All switchgear shall be delivered to the City Municipal Service Center located
at 3201 Eastbay Shore Road, Palo Alto on a weekday between the hours of
7:30am and 3:00pm. A forty-eight hours advance notice of delivery shall
be provided.
4.
All switchgear weighing less than 1,200 lbs. shall be delivered on a wood
pallet to allow unloading by forklift.
5.
Equipment damaged in shipment shall be refused on delivery. The successful
bidder shall not be relieved of the responsibility of delivering undamaged
equipment, even if the damage is internal, or otherwise goes undetected and the
nature of the damage remains unknown until the equipment is energized and
tested.
GUARANTEE
Any switchgear developing faults because of defective material, workmanship, or
design within one year from the date of delivery and acceptance shall be promptly
reconstructed, repaired, or replaced by the manufacturer without charge to the City.
The City will give notice of observed defects with reasonable promptness.
Page 21 of 25
August 21, 2001
21.
DATA TO BE SUBMITTED WITH BID
Certified test data, instruction books and drawings of equipment proposed to be
furnished under these specifications shall include detailed installation maintenance
and operating instructions along with special precautions, sequence of work and
recommendations on method of assembly. Parts catalog and other data shall be
included for easy identification of parts for ordering replacements.
22.
BID QUALIFICATIONS
1.
Bidder shall submit a current user's list of the switchgear. The list shall
include owner/agency with a contact person's name and telephone number.
2.
The City will consider the following factors in the analysis, evaluation and
subsequent bid award:
a.
b.
c.
d.
e.
f.
g.
h.
Initial cost and escalation
Delivery schedule
Conditions of bidders warranty
Completeness of bidder's data
Construction details
Bidder's experience in constructing 15KV or higher voltage
switchgear for electric utilities
Past performance of bidder and product
Other factors affecting the cost and performance over the life of
the equipment.
End Of Specification
Page 22 of 25
August 21, 2001
Electric Utilities Department – City of Palo Alto
Bid Items for supplying Deadfront, Padmounted , Vacuum Switches
with Vacuum Fault Interrupters
Bid
Item
#
01
Switch Configuration 600 Amps
Switch
3-Way, 3-Switch
2
600
Amps
VFI
1
200
Amps
Switch
200
Amps
VFI
02
1
03
2
1
04
1
2
2
05
2
1
06
1
2
07
3-Way, 3-Switch
(4Pole, with 200 A
Neutral Bushing )
2
1
08
1
2
09
2
1
10
1
2
11
2
1
12
1
2
13
4-Way, 4-Switch
Specify Type of
Control
3
1
14
2
2
15
3
1
16
2
2
Page 23 of 25
August 21, 2001
Unit
Price
Bid
Item
#
17
Switch Configuration 600 Amps
Switch
600
Amps
VFI
18
19
200
Amps
Switch
3
2
4-Way, 4-Switch
(4Pole, with 200A
Neutral Bushing)
200
Amps
VFI
1
2
3
1
20
2
2
21
3
1
22
2
2
23
3
1
24
2
2
25
5-Way, 5-Switch
4
1
26
3
2
27
2
3
28
4
1
29
3
2
30
2
3
31
4
1
32
3
2
33
2
3
Page 24 of 25
Specify Type of
Control
August 21, 2001
Unit
Price
Bidder shall provide prices for optional items separately. Bidder shall also provide
one-line schematic diagram for each bid item.
Page 25 of 25
August 21, 2001