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OWNER & CLIENT
RISING SUN ENERGY (K) PRIVATE LIMITED
EPC CONTRACTOR
STERLING & WILSON RENEWABLE ENERGY LTD
CONSULTANT
ARCHER BUSINESS SOLUTION PRIVATE LIMITED
PROJECT
TITLE OF
DOCUMENT
DRG. No:
190 MW (AC)/ 285Mwp (DC) SOLAR POWER PROJECT AT NOKH SOLAR PARK,
NOKH (JAISALMER), RAJASTHAN.
Design Basis Report - Electrical
SW-IND-RSP-DBR-E-DOC-001
EPC CONTRACTOR:
STERLING AND WILSON
RENEWABLE ENERGY LTD
CUST. DWG. NO
---
CUST. PROJ. NO
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SHEET SIZE
A4
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©COPYRIGHT STERLING & WILSON RENEWABLE ENERGY LTD COMPANY. All rights reserved.
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CONSTRUCTION
APPROVED BY
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INDEX
1
GENERAL: ................................................................................................................... 2
1.1
1.2
1.3
1.4
1.5
Introduction: ....................................................................................... 2
Project summary: ................................................................................. 2
Codes and Standards:.............................................................................. 2
Site Details: ......................................................................................... 3
Environmental Details: ............................................................................ 3
2
SYSTEM CONFIGURATION: ....................................................................................... 3
3
4
ELECTRICAL SYSTEM PARAMETERS:..................................................................... 5
MAJOR ELECTRICAL EQUIPMENTS SPECIFICATION: ........................................... 6
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
5
AUXILIARY SUPPLY SYSTEM: ................................................................................. 17
5.1
5.2
6
Solar PV Modules: .................................................................................. 6
Solar/String Cable : ................................................................................ 7
PV Cable Connector : .............................................................................. 8
PV Branch Connector : ............................................................................ 9
String Combiner Box: ............................................................................ 10
Inverter: ........................................................................................... 10
LV AC cables: ..................................................................................... 12
DC Main Cables: .................................................................................. 13
Inverter Transformer: ........................................................................... 13
MV cables: ......................................................................................... 15
Cable Sizing Philosophy with respect to Losses as per Contract: ........................ 15
MV Switchboards: ................................................................................ 16
Aux Transformers: ............................................................................... 18
UPS ................................................................................................. 18
EARTHING SYSTEM: ................................................................................................ 18
7 LIGHTNING PROTECTION SYSTEM: ....................................................................... 19
8 SCADA SYSTEMS: .................................................................................................... 19
Power Plant Controller .................................................................................................... 22
9 WEATHER STATION:................................................................................................. 22
10
11
12
13
33 kV METERING KIOSK .......................................................................................... 23
CCTV SYSTEM & FIRE ALARM SYSTEM: ............................................................... 23
ILLUMINATION SYSTEM: ......................................................................................... 23
FIRE FIGHTING SYSTEM:......................................................................................... 24
14 CABLE CONDUITS .................................................................................................... 25
15 LUGS & TERMINATION ............................................................................................. 25
16 REFERENCES –. ....................................................................................................... 25
DESIGN BASIS REPORT - ELECTRICAL
1
GENERAL:
1.1 Introduction:
This document lays down the brief system overview, design basis, various sub-system details for 190 MW
Solar PV power plant.
1.2 Project summary:
Rising Sun Energy Pvt Ltd., established in 2014. The company is working in the field of renewable energy,
particularly solar, captive, rooftop & off grid installations and into setting up of R&D facility in India in
collaboration with global partners. The Rising Sun energy has developed more than 140MW of solar plants.
Rising Sun Energy (K) Pvt Ltd. 190MW solar project is a photovoltaic power plant that will be located in
Rajasthan state of India, village Nokh Distt-Jaisalmer.
The PV plant will be interconnected through a MV 33KV Circuit to the RSDCL Switchyard. The 33 kV
metering kiosk at PSS end is considered the Point of Interconnection.
System configuration
The DC system comprises of 1500 V Zshine 540Wp,545Wp Mono Perc Half-cell PV modules. For All Wp
modules string size is 30. PV Modules will be installed on module mounting structure of 2Px60 & 2Px30
Configurations with Fixed Tilt angle of 160 and 8 Meter Pitch.
Inverter block comprises 4 Nos. of 3125 kVA / 2500 kVA 3-phase, Central Inverter and 12.5 MVA / 10 MVA,
5 winding- Inverter duty Transformer (33/0.66/0.66/0.66/0.66kV or 33/0.63/0.63/0.63/0.63kV). The output of
the transformer is fed to the 33kV ICOG panel & 33 kV 3 breaker panel (outdoor type). From ICOG / 3
breaker panel, power shall be fed to 33 kV metering kiosk located in PSS. Outgoing power from 33kV
metering kiosk Panel shall be fed to 33kV outdoor switchyard (not in SWREL scope).
1.3 Codes and Standards:
General Codes and standards which shall follow for Electrical Design of PV plant are listed below.






Indian Standard (IS) Code
IE rules/CEA regulations
CBIP Recommendations
IEEE standards
IEC standards
RRVPNL Latest guidelines
Generally, below standards shall be followed for system design, installation and testing & commissioning
for plant.



IS 1255: Cable installations
IS 3043/IEEE80/CBIP Guidelines: Earthing system design
IS 2309/NFC 17-102: Lightning protection system
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 2
DESIGN BASIS REPORT - ELECTRICAL






UL-864/IS 2189/EN 54-7/EN 54-2/EN 54-4/NFPA 72: Fire Alarm System
IEC 60945/61000-4-2, 61000-4-6, EN61326-1: Weather Monitoring System
IS 3646: Illumination/Lighting system
State Electricity Board Standards/CBIP Guideline: Substation.
IS/BS (relevant): Structure design
Equipment installations & Testing shall be done as per manufacturer’s recommendations and
applicable relevant Indian/international standards.
1.4 Site Details:
Village
Nokh
District
Jaisalmer
State
Rajasthan
Co-ordinate
27°34'50.0"N, 72°13'30.83"E
Airport
Jodhpur (200 Km), Bikaner (130 Km)
Nearest City
65KM Phalodi & 200KM from Jodhpur
GIS S/S
RSDCL Switchyard
1.5 Environmental Details:
2
Altitude
Approx. 176m above MSL
Maximum ambient temperature
50º C
Minimum Ambient Temperature
3º C
Average Wind Speed(10m):
1.6 m/s
Humidity
45.50 % (Avg.), 74 % (Max.)
Seismic Zone
II
Corrosion Category.
C-3 corrosion (Medium)
SYSTEM CONFIGURATION:
The 190 MW solar power plant system configuration overview and description are summarized as follows.
DC Capacity
285 MWp
AC Capacity
190 MWac
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 3
DESIGN BASIS REPORT - ELECTRICAL
DC to AC ratio
1.50
Tilt of Module Mounting structure (MMS)
16° Fixed
Pitch
8.0 m
Collector width
4.401 m
Inter row spacing
3.59 m
Modules per mounting structure
60 (2x30 Portrait), 120 (2x60 Portrait),
No of Inverter Transformer Stations
16 Nos
No of Inverter 3.125MW per Block
4 No.
No of Inverter 2.5MW per Block
4 No.
No. of Inverter Transformer 12.5MW per Block
1 No.
No. of ICOG/ 3 breaker panel Per Block
1 No.
Total 12.5 MW inverter room
12 Nos.
Total 10 MW inverter room
4 Nos.
Total ICOG qty
10 Nos.
Total 3 breaker panel qty
6 Nos.
ELECTRICAL SYSTEM
PV Module Type
Mono Perc Half-cell (Free issue)
Module rating
540Wp, 545Wp
Total Modules
Zshine 540Wp- 263400 Nos.
Zshine 545Wp- 261960 Nos.
Total strings
17512 Nos.
Module per string
30 modules in series- 540Wp, 545Wp
Strings per Y connector
2 nos.
Modules per MMS
120 (2x 60 Potrait) & 60 (2x30 Potrait)
2 x 30: 550 Nos., 2 x 60: 4103 Nos.,
Total MMS
NOTE: Total MMS will be as per site layout
requirement.
Inverter Type
Central
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 4
DESIGN BASIS REPORT - ELECTRICAL
ELECTRICAL SYSTEM
Inverter Rating
3125 kW @50 Degree, 2500 kW @50 Degree,
3125 KW Inverter Qty
48 Nos
2500 KW Inverter Qty
16 Nos
Inverter Transformer Type
ONAN
Inverter Transformer rating
12.5 MVA, 12 Nos., 10 MVA, 4 Nos.,
Inverter Room MV Panel
33kV Outdoor ICOG panel & 3 breaker panel
Inverter Room MV Panel Qty
ICOG panel- 10 Nos, 3 breaker panel- 6 Nos
For Overall Plant Key Single Line Diagram (Key SLD) refer drawing no.
: - SW-IND-RSP-GEN-E-SLD-101
For DC single line diagram refer drawing no.
: - SW-IND-RSP-GEN-E-SLD-100
For PLC/SCADA architecture refer drawing no.
: - SW-IND-RSP-GEN-I-DRG-901
3 ELECTRICAL SYSTEM PARAMETERS:
The following parameters are adopted in design engineering of the electrical system and associated
equipment:
1
Nominal voltage
33kV
660/630V
415V
2
Highest system voltage
36kV
-
-
3
Number of phases
3Ph, 3W
3Ph, 3W
3Ph, 4W
4
Permissible variation in voltage
±10%
±10%
±10%
5
Frequency
50Hz
50Hz
50Hz
6
Permissible
frequency
±3%
±3%
±3%
7
Combined variations in voltage
10%
and frequency (absolute)
10%
10%
variation
Doc No. SW-IND-RSP-GEN-E-DBR-001
in
Page 5
DESIGN BASIS REPORT - ELECTRICAL
4
8
Maximum fault level
25 kA for 1
50 kA for 1 sec
sec
10 kA for 1sec
9
System neutral earthing
Solidly
earthed
Solidly earthed
Floating
MAJOR ELECTRICAL EQUIPMENTS SPECIFICATION:
This design basis covers the major electrical systems/ equipment/ commodities and design philosophy
for the proposed PV solar power plant.
1. Solar PV module- Zshine 540Wp, 545Wp Mono Perc Half-cell module
2. Solar cable (String cable)
3. PV branch connectors
4. String Combiner Box
5. LT cables
6. Inverter
7. Inverter Transformer
8. MV cables
9. MV switchgears
10. Aux. Power supply system
11. UPS & Battery
12. Battery & Battery charger
13. Earthing, Lightning, Illumination
14. Plant Communication & SLDC/NRLDC connectivity
4.1 Solar PV Modules:
The PV module converts the sunlight into DC electricity and certified for use up to system voltage of 1500
VDC. The Salient features for the PV module are as follows:
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 6
DESIGN BASIS REPORT - ELECTRICAL
Description of parameter
Unit
Nominal Values
Nominal Power (± 5%)
PMPP (W)
540 Wp
545 Wp
Voltage at Pmax
VMPP (V)
41.40 V
41.60 V
Current at Pmax
IMPP (A)
13.05 A
13.11 A
Open Circuit Voltage
VOC (V)
49.70 V
49.90 V
Short Circuit Current
ISC (A)
13.78 A
13.84 A
Maximum System Voltage
VSYS (V)
1500 V
1500 V
Maximum Series Fuse
ICF (A)
25 A
25 A
(°C)
44±2℃
44±2℃
-0.35%/℃
-0.35%/℃
Nominal
Operating
Temperature
Temperature
PMAX
Cell
Coefficient
of TK
(PMAX)
Temperature Coefficient of VOC
TK (VOC)
-0.29%/℃
-0.29%/℃
Temperature Coefficient of ISC
TK (ISC)
0.05%/℃
0.05%/℃
NOTE: Terminal cable length of 1200 mm to be provided with PV Modules. Supply of PV Module is not in
scope of EPC contractor.
4.2 Solar/String Cable :
Solar cable of size 6mm2 Copper is used for connecting strings to string combiner box.
Cable size is chosen based on the acceptable/reasonable power loss and voltage drop. The typical solar
cable specification is as below:
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 7
DESIGN BASIS REPORT - ELECTRICAL
Description
Nominal values
Cable size
1Cx6 mm2
Nominal Voltage
1500 V dc
Conductor material & type
Annealed Tinned Flexible Copper Conductor as per EN 60228
Temperature range
-40°C to +90°C (max. conductor temperature is 120°C)
Insulation/Outer sheath type
Electron bean cross-linked polyolefin co-polymer (XLPO)
Armouring
Unarmoured
Properties
UV, Flame Resistant, Weather, Halogen Free
Applicable standard
IEC60811-404, EN50396, IEC60332-1-2, IEC60068-2-78,
IEC60287, IEC61034-2, EN 50395, EN 50252-1
Approval
EN 50618
4.3 PV Cable Connector :
Connectors are integral part of string connection of solar power which is used for string interconnection
and also interconnect the parallel connection solar output from the Y connector to another solar cable
which is intended to further connect to the String Combiner Box.
The typical connector specification is as below:
Description
Rated Voltage
Rated Current
Connector type/compatible
Contact Material
Ambient temperature range
Over Voltage category/Pollution degree
Max temperature
Contact Resistance
Type of termination
Insulation Material
Doc No. SW-IND-RSP-GEN-E-DBR-001
Nominal values
1500V DC
50 A (6 mm2 ; 10AWG)
PV-JK03M/xy series
Copper, tin plated.
-40 to +85 ̊C
CATIII/2
110 ̊C
≤ 0.3mΩ
Crimping
PPE/PA
Page 8
DESIGN BASIS REPORT - ELECTRICAL
Protection class
Applicable standard
Degree of Protection
II
TÜV IEC 62852:2014 ; UL6703；IEC61730
IP 68
4.4 PV Branch Connector :
PV branch connector of 2 in and 1 out type is proposed for first level string paralleling at module mounting
structure. Two strings are paralleled through branch connector & the output of branch connector will be
connected to String combiner box.
The salient features of branch connector specifications are provided as below:
Description
Nominal values
System voltage
1500V DC
Type/Configuration/No of ways
Rated Current
PV-JK03M/xy series ,2 in & 1 out
50 A (6 mm2 ; 10AWG)
Ambient Temperature
500C
Degree of Protection
IP 68
Application Class
Class A
Overvoltage Category / Pollution Degree
CAT III/2
Fuse rating
Fuse connector of 25A rating considered where
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 9
DESIGN BASIS REPORT - ELECTRICAL
Contact Resistance
two strings are paralleled. (only for positive side)
≤ 0.5mΩ
Protection Class
Class II
Conduction Material
Silver Plated copper alloy
Fuse assembly type
Removable type with male & female connector
Connectors
PV Cable Connectors
Applicable standard
TÜV IEC 62852:2014 ; UL6703；IEC61730
4.5 String Combiner Box:
Power from strings is combined at string combiner box (SCB). String combiner box essentially comprises of
positive and negative bus, fuses, type 1+2 rated surge arrestors and dis-connector switch. From SCB the
power is further transferred to inverter through DC cable. Details of SCB are as follows:
Description
Nominal values
Rating
12+1 spare Input String Combiner Box
Number of Inputs
12+1 spare
No of Fuse per Input
1 Nos / String on +Ve side
Fuse Rating
50 Amps
Rated System Voltage
1500Volts DC
Disconnector Switch Rating
500A/1500V
Enclosure Material
FRP
Degree of Protection
Output SPD Type
IP-65, IK-10, (UL94Vo Flammability
rating, UV resistance Test upto 2500Hrs.)
Type- I+II SPD at 1500V O/P
4.6 Inverter:
The Sineng make EP-3125-H B-UD & EP-2500-HA-UD Inverters are proposed. The inverter converts the
DC power to AC power to facilitate feeding into the grid. The Salient features for the grid connect inverter
are as follows:
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 10
DESIGN BASIS REPORT - ELECTRICAL
Description
Nominal values
Nominal DC Input Power
3125 kW at 50˚C, 2500 kW at 50˚C
Maximum DC Input Power
MPP Voltage
150% of Nominal at 50˚C
945 Vdc to 1300 Vdc, 900 Vdc to 1300 Vdc
Input Current
4036A, 3260A
Rated AC Output Power
3125 kW @ Cosϕ 1 & 50⁰C, 2500 kW @ Cosϕ 1 & 50⁰C
Maximum AC Power at Cos ф=1
3738kVA at 30⁰C , 2875kVA at 30⁰C
AC Voltage
660V, 50Hz, 3 Phase, 630V, 50Hz, 3 Phase
Maximum AC Current
3270 A, 2635 A
Maximum Efficiency
99.00%
Euro Efficiency
98.70%
Internal Consumption
<4.0kW
Degree of protection
IP65
Ambient Temperature
-30˚C to 60˚C
Derating Temperature
>50˚C
Inbuilt Protections
DC Side
Over Voltage Protection
Over Current Protection
Reverse Polarity
Anti PID
Negative Grounding
Ground Fault Monitoring
Insulation Monitoring
Over Heat Protection
Surge Protection (Type I+II, Y configuration as per IEC
61643)
Short Circuit Protection
Fan Protection
Emergency Switch
AC side
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 11
DESIGN BASIS REPORT - ELECTRICAL
Description
Nominal values
Over / Under Voltage Protection
Over Current Protection
Current Balance
Over / Under Frequency Protection
Short Circuit Protection
Surge Protection (Type II, Y configuration as per IEC
61643)
Earth Fault
4.7 LV AC cables:
1Cx400 mm2 1.9/3.3kV [E] XLPE armoured Aluminium conductor LV cables shall be laid on the cable tray
for connecting Inverter to Inverter Transformer. The cables size is selected considering the service current
carrying capacity, short circuit current, and voltage drop and power loss criteria.
Description
Nominal values
Cable size
1Cx400 mm2
Nominal Voltage
1.9/3.3kV [E]
Conductor material & type
Aluminium Stranded Compacted sector &
Class 2
Operating conductor range
0 °C to 90° C
Insulation
Extruded XLPE Insulation as per IS: 7098 (P2) -2011
Armouring
Flat strip H4 Grade
8130/2013 & IS: 3975
Outer sheath type
Extruded FR PVC ST2 as per IS 5831 - 1984
Applicable standard
IS 7098 Part II
Doc No. SW-IND-RSP-GEN-E-DBR-001
Aluminium
to
IS
Page 12
DESIGN BASIS REPORT - ELECTRICAL
4.8 DC Main Cables:
1Cx300/400 mm2 1.9/3.3kV [E] XLPE armoured Aluminium conductor LV cables shall be laid in Ground
from SCB to Inverter. The cables size is selected considering the service current carrying capacity, short
circuit current, and voltage drop and power loss criteria.
Description
Nominal values
Cable size
1Cx300 / 400 mm2
Nominal Voltage
1.9/3.3kV [E]
Conductor material & type
Aluminium Stranded Compacted sector &
Class 2
Operating conductor range
0 °C to 90° C
Insulation
Extruded XLPE Insulation as per IS: 7098 (P2) -2011
Armouring
Flat strip H4 Grade
8130/2013 & IS: 3975
Outer sheath type
Extruded FR PVC ST2 as per IS 5831 - 1984
Applicable standard
IS 7098 Part II
Aluminium
to
IS
4.9 Inverter Transformer:
12.5 MVA & 10 MVA capacity of the five winding step-up inverter duty transformer shall be chosen to suit
the rated MVA capacity of the inverter for an ambient temperature of 50°C.
The Salient features for the step-up transformer are as follows;
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 13
DESIGN BASIS REPORT - ELECTRICAL
Description
Nominal values
Rating
12.5 MVA, 33/.660/.660/.660/.660 kV
10 MVA, 33/.630/.630/.630/.630 kV
Service
Outdoor
Number of phases
Three
Voltage
HV – 33kV, LV – 660 / 630 V
Frequency
50Hz
Rated Current
1. HV
218.69 A , 174.95 A
2. LV.
4x2733.74 , 2291.13 A
Vector group
Yd11d11d11d11
Type of cooling
ONAN
Impedance (%):
7% (+/- IS Tol)
Insulation Level
1. LV
40kVp/10kVrms
2. HV
170kVp/70kVrms
Temp. rise over reference ambient
1. In oil thermometer
1. 50 °C
2. In winding by resistance
2. 55 °C
Losses at Full Load at Unity PF
No Load Loss
Load Loss
Type of tap changer
Tapping range
Approximate maximum Flux density Web/m2
1. At 90% rated voltage
2. At 100% rated voltage
3. At 110% rated voltage
The Oil filled transformer is equipped
with protections.
Doc No. SW-IND-RSP-GEN-E-DBR-001
0.1%
0.9%
OCTC (off load tap changer)
+10% to –10%% in step of 2.5%
1.55 T
1.7 T
1.87 T
‐ Bucholz trip (63T) - (transformer mounted via
marshalling box)
‐ Oil Temperature trip (26T)- (transformer
mounted via marshalling box)
‐ Winding Temperature trip (49) - (transformer
Page 14
DESIGN BASIS REPORT - ELECTRICAL
‐
4.10
mounted via marshalling box)
Pressure Relief Device mounted via marshalling box)
(transformer
MV cables:
1Cx185 mm2 & 1Cx300 mm2 33kV (E) XLPE armoured aluminium conductor cable, direct buried shall be
used as required. The cables sizes are selected considering the short circuit current, service current
carrying capacity, voltage drop and power loss criteria, Armour & metallic shield shall be as per calculated
fault level and relay coordination. Underground Laying of cables will be with cable tie arrangement and
above ground will be with trefoil arrangement.
Description
Nominal values
Cable size
1Cx185 mm2 & 1Cx300 mm2 *
Nominal Voltage
19/33 kV(E)
Conductor material & type
H4 Grade as per latest amendment of IS 8130 Aluminium
Stranded Compacted circular & Class 2
Max. conductor temperature
90°C – Normal continuous operation
250°C – Short circuit condition
Conductor shielding
Extruded layer of semi-conducting compound
Insulation
Extruded XLPE as per IS:7098(P-2)/2011
Insulation shielding
Extruded layer of non-magnetic semi-conducting compound
Inner sheath
Not applicable
Armouring
Aluminium Round Wire suitable to meet the calculated fault
level for duration as per relay coordination.
Outer sheath
FR Extruded PVC ST2 (UV Protected with Anti-termite & anti
rodent properties)
Applicable standard
IS 7098 Part II
4.11
Cable Sizing Philosophy with respect to Losses as per Contract:
DC POWER losses can be proposed less than @ 1.75% average at Inverter level in the cable design
calculations at 50 degree.
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 15
DESIGN BASIS REPORT - ELECTRICAL
Note: All DC cable shall be laid below MMS.

4.12
Overall AC Cable & Conductor loss will be 0.5% (i.e. from Inverter AC output till 33kV outgoing line).
cable design calculations at 50 degree.
MV Switchboards:
The 33kV MV switchboards shall have following features;





It shall be VCB, enclosed in air insulated switchboard type.
Breaker shall have 3 positions-open, closed and earthed. Position of the power & earthing
contacts shall be clearly visible on the front of the switchboard. Appropriate natural interlocking
arrangement shall be done within the breaker to avoid unauthorized operations.
Breaker manual TRIP arrangement with integrated push button on panel shall be provided. An
operating mechanism can be used to manually close the circuit breaker and charge the
mechanism.
For 33kV Outdoor Type 33kV ICOG & 3 breaker Panel Control Supply for Closing coil, Tripping
coil, Spring Charging motor, Protection & Auxiliary Relays and Indicating lamps will be 240 V AC
UPS Supply with operating voltage range 85% to 110%.
IEC 61850 Modbus Protocol to be followed for communication of relays & RS 485 for MFM with
PLC/SCADA.
The brief configuration of various 33kV MV Panels are described as given below;
(a) 33kV ICOG @ Inverter station –Outdoor (IP55, 25kA for 1 Sec) - 10 Nos.
Type
feeder
of No
of
Application
feeder
Breaker
01
Transformer
and feeder
VCB Rating
Earth
switch
630 A, SC 1 no
Rating: 25 kA
for 3 sec @
STC
Protection
Power
Measurement
50/51,
Through 0.5
50N/51N, 86, Class MFM
95 71, 63X,
49X,87T, 94,
80AC,PT fuse
failure
GE P645
(a) 33kV 3 Breaker panel @ Inverter station –Outdoor (IP55, 25kA for 1 Sec)- 6 Nos.
Type
feeder
Breaker
of
No of feeder
Application
01
Outgoing
Power
Doc No. SW-IND-RSP-GEN-E-DBR-001
VCB Rating
Protection
to 630A, SC Rating --25kA for 3 sec.
Power
Measurement
---
Page 16
DESIGN BASIS REPORT - ELECTRICAL
Transformer
Breaker
Breaker
1
1
Incoming
from
Adjacent
ICOG-Panel
630A, SC Rating 50/51,
Through 0.5
25kA for 3 sec
50N/51N,
Class MFM
86, 94, 95,
80AC,
Relay ABB
REF 615H
630A, SC Rating 50/51,
Through 0.5
25kA for 3 sec
50N/51N,
Class MFM
86, 95 71,
Incoming
63X,
from Inverter
49X,87T, 94,
trafo
80AC,PT
fuse failure
GE P645
SWITCHGEAR OPERATIONAL INTERLOCK
Circuit breaker & respective earth switch
Mechanical
Prevent the removal of respective cable covers if circuit
Electrical / Mechanical
breaker is ‘ON’
Prevent the closure of circuit breaker if respective cable cover
Electrical / Mechanical
is open
Cable test plug for CB accessible only if Earth switch
Mechanical
connected to earth
5
AUXILIARY SUPPLY SYSTEM:
For Auxiliary supply system refer drawing no: - SW-IND-RSP-GEN-E-SLD-102
The plant auxiliary power supply shall be arranged by de-centralized distribution system. Each Inverter
blocks are fed from suitably sized auxiliary transformers located in the inverter station and further will be
distributed to various loads. Redundant supply for each inverter room by looping power supply with another
Doc No. SW-IND-RSP-GEN-E-DBR-001
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DESIGN BASIS REPORT - ELECTRICAL
nearest inverter room. Auxiliary transformer is suitably sized for two inverter room loads in case of failure of
one Auxiliary transformer. Auxiliary transformer No-Load Loss <= 0.5%, Load Loss Max <= 2.5% Efficiency
97.5% at unity PF and full load. Aux loss of total plant will be 0.4%.
5.1 Aux Transformers:
Rating
20kVA, 660 or 630 / 415V 50kVA, 660 or 630 / 415V - 63kVA, 660 or 630 / 415V
– 8Nos.
4Nos.
- 4 Nos
Type
Dry type
Oil type
Oil type
5.2 UPS
Rating
3 kVA- 8Nos.
10 kVA- 1No.
Battery Backup & type
120mins back up for ICR station; 120 mins back up for MCR; 12 V VRLA
12 V VRLA Batteries
Batteries
Location
Inverter station
Main Control Room
6 EARTHING SYSTEM:
The Codes and standards referred for the design of earthing systems are as given below;








‐ IS 3043: Code of practice for Earthing – Maintenance free Earth pits considered.
‐ IS 3043/ IEEE 80, whichever applicable.
Earthing system shall be in strict accordance with IS 3043 and Indian electricity rules/ acts.
260-ohm mtr. resistivity considered for design. maintenance free earth pit (Carbon based) with
resistivity value of less than or equal to 0.7 ohm-m, 150 mm dia and 17.2mm copper clad steel rod
of depth 3 mtr. Resistance of individual pit subject to change with change in resistivity value. AC
/DC earthing grid and individual earth pits shall be connected and equipotential bonding shall be
maintained.
Metallic frame of all electrical equipment shall be earthed by two separate and distinct connections
to earthing system.
Earth Strip shall be installed in DC and MV cable trench along the cables and where separate
trench to provided for earthing 600mm depth shall be kept.
Connections between earth leads and equipment shall normally be of bolted type. Contact surfaces
shall be thoroughly cleaned before connections. Equipment bolted connections after being tested
and checked shall be painted with anti-corrosive paint/compound.
Connections between equipment earthing leads and between main earthing conductors shall be of
welded/bolted type. For rust protection the welds should be treated with red lead compound and
afterwards thickly coated with bitumen compound.
The material of the earthing conductors shall be as follows:
Conductors above ground level and in built up trenches and buried - Galvanized steel earth strips
Doc No. SW-IND-RSP-GEN-E-DBR-001
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DESIGN BASIS REPORT - ELECTRICAL





7
Earth electrodes @ Inverter Station & PV Yard – Maintenance free earth electrodes shall be
provided for Inverter Stations, main control room & PV yard.
The suitably sized earthing conductors for various electrical equipment’s based on prospective short
circuit current.
The exact size of earthing conductors required for various equipment and number of earth pits
required to be used are detailed in respective design calculations.
Module earthing shall be done as per installation guidelines of module manufacturer.
All AC, DC, LA, earthing will be interconnected as per IEC-61000-5-02 1997 and overall resistance
shall be less than 1 ohm. SCADA earthing will be separated and resistance value for SCADA shall
be less than 4 ohms.
LIGHTNING PROTECTION SYSTEM:
The Codes and standards referred for the design of lightning protection system is as given
below;
IS 2309: Code of Practice for the protection of building and allied structures against
lightning
‐ French standard NFC: 17-102-2011
The Inverter Station and PV area will be protected from external lightning. The protection system will
be based on ESE (early streamer emission) lightning conductor air terminals as per NFC.
The air terminals shall provide an umbrella protection against direct lightning strike covering a radial
distance of maximum 107m with Level-IV protection. The air terminal will be capable of handling
multiple strikes of lightning current and should be maintenance free after installation.
The earthing stations for the lightning discharges shall be provided with test links and located at
1500mm above ground level in an easily accessible position for testing.
LA Shadow from 8:30 AM to 4:30 PM to be considered. Accordingly, required shadow free space to
be left around it.
Each ESE LA will be provided with provided with Electromechanical Lightning strike counter.
We will be providing two earth pits for each LA and both earth pits will be connected to DC Main grid
as per IEC-61000-5-02 1997.
‐






8
SCADA SYSTEMS:
The Monitoring & Control system will be a PLC based rugged solution for providing the data acquisition,
analysis, reporting and real-time performance monitoring from site and from remote location (through
Internet).
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DESIGN BASIS REPORT - ELECTRICAL
The power plant shall be provided SCADA system to monitor the input & output of each Inverter,
Transformers, MV switchgear panels and weather stations so that system faults can be detected and
rectified before they have an impact on production. Internet portal solution will be provided to access all
data acquisition and real time performance monitoring can be done from office or remote areas.
The SCADA system shall be composed of an integrated human-machine interface (HMI), input/output (I/O),
PLCs communication infrastructure and software. SCADA for PV plant signals (MCR &ICR) considered.
Redundant PLC controller considered for MCR PLC Panel.
Remote PLC’s and I/O’s shall be used to collect data from various devises to transfer data to server which
will carry out key functions.
Detailed SCADA Architecture is mentioned in SW-IND-RSP-GEN-I-DRG-901 document.
Plant Parameters:








Inverter: Each input current monitoring, DC/AC voltage, power, pf, Energy
MV switchgear panels at various inverter blocks: Transformer faults, relays, breaker & MFM data
MV switchgear panel at Evacuation/Interconnection point (within plant): Active & Reactive Energy
(Import/Export), Power factor (Import/export), Power, Voltage, frequencies, Grid status, Breaker
status, Relay status & etc.
Plant to LDC- As per Applicable grid code/NRLDC requirements.
Plant Performance ratio on daily/monthly/quarterly/annual basis.
Plant Capacity Utilization Factor on daily/monthly/quarterly/annual basis.
Ring topology over OFC network considered for maintaining redundancy.
Detailed IO signals (soft and hard-wired signals) are mentioned in SW-IND-RSP-GEN-I-LIST-902
document.
REMOTE MONITORING OF SCADA:
Apart from being able to Monitor the plant activities locally at site, monitoring of the plant on the SCADA
application remotely via internet is considered with 3 web client licenses. The data exchange must be done
over dedicated synchronous bandwidth over static IP. Internet must be routed through Firewall to ensure
security of the operational system.
PLANT COMMUNICATION & SLDC/NRLDC CONNECTIVITY:
Telemetry system for real time data communication from PV Plant to RSDCL grid sub-station via
OFC considered.
System Requirements:
 Collect required parameters (All inverters, incomer, outgoing, WMS all analog and digital status from
PV solar plant SCADA via redundant MODBUS TCP master ports.
 Provide all the required parameters same to RSDCL via redundant IEC-104 slave links.
 Provide optical interface components at solar plant and RSDCL Grid substation.
Exact I/O point will be decided during detailed engineering as per NRLDC requirement.
Doc No. SW-IND-RSP-GEN-E-DBR-001
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DESIGN BASIS REPORT - ELECTRICAL
Meteorological Parameter: Following parameters will be integrating with SCADA through WMS
datalogger.






Global Horizontal Irradiation.
Global Irradiance on inclined plain.
Ambient air temperature.
Relative humidity.
Module temperature.
Wind speed and direction.
A Combination of MODBUS RS485, TCP/IP / LAN and Optic Fibre cables shall be used in a distributed
network for communication between Field device. Likewise, the communication network at all the Inverter
Blocks shall be connected to the main control room via OFC.
CCTV will be communicating to NVR at MCR through same network.
The PV Plant SCADA architecture worked out shall be referred for further details and understandings.
Brief of SCADA specification as below.

The system shall be provided with Supervisory Station that will refer to the server and software
responsible for communicating with the field equipment, and then to the HMI software running on
workstations in the main control room.
Combination of Modbus, Industrial grade Ethernet LAN and fibre optic network shall be distributed
throughout the field for communication to field devices. FO Cable network shall be in ring topology for
better redundancy. The 2 nos. of OMS and EMS server to be chosen with Raid Configuration, redundant
power supply and dual Ethernet. 50 Inch HD quality 1 No Monitor additional for viewing at SCADA room

The SCADA shall be PLC based and shall be provided with two processors (Main processing unit
and memories) one for normal operation and one as hot standby. In case of failure of working processor,
there shall be an appropriate alarm and processor shall be totally bump less and shall not cause any plant
disturbance whatsoever. In the event of both processors failing, the system shall revert to fail safe mode. It
shall be possible to keep any of the processors as master and other as standby. The standby processor
shall be updated in line with the changes made in working processor.
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DESIGN BASIS REPORT - ELECTRICAL

Communication protocol for shall be based Modbus and TCP/IP.
Power Plant Controller
The power plant controller shall be integrated with the SCADA and operation of Power Plant
Controller will be through a dedicated system.

Power Plant Controller (PPC) designed mainly to communicate and to regulate the reactive
power of the PV plant, in such a way that the PV plant is watched like a single generator at the Point
of Interconnection.
Redundant Power plant controller (PPC) system with monitor considered.
The control system can provide the following functionalities (in coordination and depending on the
capability of the inverters).

Active power curtailment
This functionality limits the active power at the Point of interconnection to a defined value,
dispatching suitable reference values to the available inverters ramp rate limiter is used on the set
points. Ramp rate limiter is the feature of inverter to control the active power export from inverter.

Voltage / Reactive power regulation
The system operates alternately (in one of the three modes) by power factor control, voltage control
or reactive power control at the point of interconnection, dispatching suitable reference values to the
available inverters
9 WEATHER STATION:
The power plant weather station (self-powered -solar panel with battery) comprises the below
sensors/instruments which are used for different purposes are as follows:
Primary WMS System: 3 Sets.
 Datalogger- 1 No.
 Ethernet Interface with Extended data Storage Module- 1 No.
 Pyranometer- SMP10- 2 Nos.
 Ambient Temperature & Relative humidity sensor- 1 No.
 Anemometer & Wind Wane- 1 No.
 Module Temperature Sensor- 4 Nos.
 Rain Gauge Sensor- 1 No.
 Barometric Pressure sensor- 1 No.
 Power Supply- 1 No.
 Mounting Hardware & Enclosure- 1 No.
 Soiling station- 1 No.
SLDC Sensors
 Cloud Cover Sensor -1No
 Diffuse & Direct Irradiance Sensor with Tracker-1No
Secondary WMS Components: 7 Sets
 Tilted Pyranometer - 1No
 Module Temperature Sensor -2 Nos
 Data logger - 1No
 Mounting Hardware & Enclosure - 1 No
 Power supply - 1 No
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DESIGN BASIS REPORT - ELECTRICAL
Soiling station shall be provided to monitor and analyse the effect of soiling on the energy generation
through PV Modules. This shall be a standalone system integrated with the plant monitoring system. The
system shall essentially comprise of two modules, of which one can soil naturally while the other is cleaned
as per the PV module cleaning regime. Power output of both the modules shall be monitored thus enabling
the O&M team to determine the optimized cleaning schedules.
Proposed WMS datalogger will communicate to SCADA through TCP/IP Modbus Protocol and soiling
station will communicate with SCADA directly through TCP/IP Modbus protocol.
10 33 kV METERING KIOSK
33kV Metering Kiosk shall be placed in PSS area. The Metering boards shall have outdoor IP55 protection
class having Double door front, single tier, fully compartmentalized, metal enclosed construction. It shall
consist of TVM meter along with metering CT, PT and LA.Tri vector meter (TVM) shall be communicable
with SCADA and have RS485 communication Port. It will be used for measurement of PR. It shall comply
with RSDCL technical specification.
11 CCTV SYSTEM & FIRE ALARM SYSTEM:
CCTV will be communicating to NVR at MCR through same OFC network considered for SCADA.
CCTV monitoring at MCR considered.
SL
1
2
3
4
5
Item Description
PTZ Type CCTV Camera
@ Main gate + Strategic locations
Bullet Type CCTV Camera for ICR, entry and exit
gate
Dome Type CCTV Camera @each Security cabin
and Inside MCR entrance and SCADA room
NETWORK VIDEO RECORDER – 64
CHANNELS
53# LED MONITOR @ SCADA room
Unit
Qty
7
Nos
23
Nos
9
Nos
1
No
1
No
Conventional type FAS shall be installed in MCR and each ICR.
Conventional fire alarm systems and its components are all wired to the same cable that connects them to
a fire alarm control panel. When a component is activated, a signal is displayed on the control panel.
12 ILLUMINATION SYSTEM:
Lighting shall be designed with LED light fixture and lux level as follow:
S. No
Location
Doc No. SW-IND-RSP-GEN-E-DBR-001
Light fixture
Page 23
DESIGN BASIS REPORT - ELECTRICAL
1
2
Inverter area, ICOG panel, Transformer area
Periphery road
Average of 50lux for the
inverter stations
.
30 W LED mounted on 4 M
High Lighting Pole installed
at every 40 Meters along
the peripheral road.
Avg lux will be 5.
LED fixtures aligned to
achieve
lux
level
as
mentioned for below areas
Main Control Room
3

Avg 300 lux for the main
control room, admin /
SCADA rooms, 200 lux in
switchgear
shall
be
maintained
20% Lights in MCR, Inverter Station & Switchyard will be fed through emergency supply.
13 FIRE FIGHTING SYSTEM:
The solar PV plant shall be equipped with suitable fire protection and fighting systems for entire PV array
area, all control rooms as per the fire safety standards and local fire authority requirements. Firefighting
of transformers and other electrical equipment’s as required shall be in accordance to tariff advisory
committee guidelines, CBIP, IS 10028, NFPA 190 and NFPA 15.
Fire Extinguishers: Portable type fire extinguishers conforming IS10658 shall be provided as means
of dealing effectively and immediately with fire caused from oils, solvents, gases, paints, varnishes,
electrical wiring and all flammable liquids and gases. System shall comply with required insurance
norms. Following type of portable fire extinguishers shall be provided in PV array area, modular block
control rooms and main control room.



DCP type fire extinguisher
CO2 operated hand portable extinguisher
Foam type hand portable extinguisher
Fire buckets: Fire buckets shall be provided in all modular unit control rooms with fine sand and fixed
on an angle iron frame as per requirement of local authorities. Fire buckets shall be painted red with
additional handle at the bottom and a cover to avoid moistening of sand.
NIFPS: Oil filled Inverter transformer shall be provided with a dedicated Nitrogen Injection system for
prevention against the transformer explosion which shall use nitrogen as quenching medium. The system
shall prevent Transformer oil tank explosion and possible fire in case of internal / external cause. NIFPS
panel shall be made of CRCA sheet of 3mm (minimum) thick complete with the base frame, painted inside
Doc No. SW-IND-RSP-GEN-E-DBR-001
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DESIGN BASIS REPORT - ELECTRICAL
and outside with post office red colour. It consists of Nitrogen gas cylinder with regulator, drain pipes,
pressure monitoring switch. It will have Control box for monitoring system operation, automatic control, and
remote operation. NIFPS Panel shall be mounted inside inverter control room.
14 CABLE CONDUITS

40/32 MM Diameter DWC HDPE pipe consisting of two layers, i.e. the outer layer is corrugated and
the inner layer is plain and smooth will be used for laying the UV rated string cables and
unarmoured communication cables (if any).

Similar potential cables in flexible conduit will be laid to avoid any risk of short circuits.

Conduit filling will be as per cable sizing calculation taking all applicable derating factors into
consideration. Conduits shall not be filled more than 40% of inside space.

UV protected and helogen free material will be used for manufacturing of 40/32 MM Diameter DWC
HDPE pipe.
15 LUGS & TERMINATION



Type, material and dimension of lugs will be based on terminal busbar and equipment
manufacturer recommendation for termination.
Termination of 33kV cables heat shrinkable type termination kits as per IS: 13573- Part 2, 2011
will be used for for indoor/outdoor installation.
Bimetallic lug intend to be installed on circular or pre-rounded sectorial shaped, stranded,
compacted aluminum conductors of power cables as terminals connected to copper busbars.
Copper as per IS -191 & Aluminum as per IS-5082.
 All power cable terminals lugs will be conforming to IS : 8309. The dimension and tolerances as
per as per Table-2 of IS: 8309.
16 REFERENCES –.
Master Drawing List (which is capturing all the major design documents).
Doc No. SW-IND-RSP-GEN-E-DBR-001
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DESIGN BASIS REPORT - ELECTRICAL
NOTE: IN SOME PART OF THIS DOCUMENTS THE PICTURES OR SNAPS SHOWN IS JUST FOR
ILLUSTRATION PURPOSE ONLY.
- END -
Doc No. SW-IND-RSP-GEN-E-DBR-001
Page 26
Customer
RISING SUN ENERGY (K) PRIVATE LIMITED
Consultant
ARCHER BUSINESS SOLUTION PVT LTD
EPC
STERLING & WILSON RENEWABLE ENERGY LTD.
Project name
190 MW (AC)/ 285Mwp (DC) SOLAR POWER PROJECT AT NOKH SOLAR PARK, NOKH (JAISALMER), RAJASTHAN.
Drawing/
Document No.
Subject
Revision No.
SW-IND-RSP-DBR-E-DOC-001
COMMENTS ON DESIGN BASIS REPORT - ELECTRICAL
Sr. No.
R1
Rising Sun Energy/ Archer Business Solution
Comments
SWSL Response
RSEKPL / ABSPL
Response
1
Clause 1.2, Page-3, Line-1: Name of Client to be written as
Rising Sun Energy Pvt Ltd.
Revised
Noted
2
Clause 1.2, Page-3, Para-2: Name of Client/SPV to be
written as Rising Sun Energy (K) Pvt Ltd.
Revised
Noted
3
4
5
6
7
Plant Communication & SLDC Connectivity: Include NRLDC with
Revised
SLDC.
Illumination System: Mention Lux level of Periphery Road Lighting
Revised
also.
Kiosk details included. PPC detail is already mentioned.pls
Details of 33kV Kiosk, PPC to be included.
refer SCADA part.
Fire fighting system revised and Fire alarm system is already
Details of Fire Fighting to be included.
mentioned in CCTV and FAS.
Fault Current Consideration reference to be mentioned in the
33kV fault level 25kA as per RFQ, 660 V side as per inverter
document
trafo imp. 3125/1.732/.66/.07 = 39kA and DC side max feed
5kA. However we have considered 50 kA which is more.
For 415 V side max Aux trafo 63KVA having imp 4% so fault
current at 415V side =63/.04/1.732/415 = 2.2 kA however we
have considered the equipment for 10kA.
detail SC fault current calculation will be submitted seperately
for approval.
Noted
Noted
Noted
Noted
Noted