(Grid Connected Solar Rooftop Photo Voltaic (SPV) power plant-with/without battery bank)

The projects shall be installed and commissioned as per the technical specifications given below.


A Grid Connected Solar Rooftop Photo Voltaic (SPV) power plant consists of SPV array, Module Mounting Structure, Inverter/Power Conditioning Unit (PCU) consisting of Maximum Power Point Tracker (MPPT), and Controls & Protections, interconnect cables and switches. PV Array is mounted on a suitable structure. Grid connected SPV power plant may be with or without battery and should be designed with necessary features to supplement the grid power during day time. Components and parts used in the SPV power plants including the PV modules, metallic structures, cables, junction box, switches, inverters/PCUs, battery etc., should conform to the BIS or IEC or international specifications, wherever such specifications are available and applicable.

  • Solar PV system shall consist of following equipments/components.
  • Solar PV modules consisting of required number of Crystalline PV cells.
  • Grid interactive Inverter with Remote Monitoring System 
  • LiFePO4 Battery bank (for Hybrid System)
  • Mounting structures  
  • Junction Boxes.
  • Earthing and lightening protections.
  • IR/UV protected PVC Cables, pipes and accessories


  1. The PV modules shall be of indigenous make.
  2. The efficiency of the PV modules should be minimum 16% and fill factor should be more than 70%.
  3. Modules of mono/poly crystalline type can be used.
  4. The PV modules used must qualify to the latest edition of IEC PV module qualification test or equivalent BIS standards Crystalline Silicon Solar Cell Modules. In addition, the modules must conform to IEC 61730 Part-1 - requirements for construction & Part 2 – requirements for testing, for safety qualification or equivalent IS. a) For the PV modules to be used in a highly corrosive atmosphere throughout their lifetime, they must qualify to IEC 61701. Certificate for module qualification from IEC or equivalent to be submitted as part of the bid offer. Self undertaking from manufacturer / supplier that the modules being supplied are as per above. The Potential Induced Degradation (PID) test for solar modules will be mandatory. It should be valid during the operational period.
  5. Module shall consists of Solar Cell of minimum 4 Bus Bar technology. At the time of supply the supplier shall submit the certificate from the manufacturer of the module certifying that he has supplied the modules to …………………. (name of supplier) strictly manufactured as per BOM of IEC certificate mentioning the technology of the solar cell (as per Performa- VI).
  6. The modules of the manufacturers who are having OEM and co-certification will not be considered as qualified modules.
  7. The total solar PV array capacity should not be less than allocated capacity (kWp) and should comprise of solar crystalline modules of minimum 300 Wp (with 72 cells) and above wattage for the project above 5 kWp and of minimum 250 Wp (with 60 cells) and above wattage for the project upto 5kWp. Module capacity less than minimum of these wattage shall not be accepted.  
  8. Protective devices against surges at the DC side shall be provided. Low voltage drop bypass diodes shall be provided. 
  9. PV modules must be tested and approved by one of the IEC authorized test centres and shall meet the latest higher side specifications prescribed by MNRE/HAREDA.
  10. The module frame shall be made of corrosion resistant materials, preferably having anodized aluminum.
  11. The bidder shall carefully design & accommodate requisite numbers of the modules to achieve the rated power in his bid.
  12. Other general requirement for the PV modules and subsystems shall be the Following:
  1. The rated output power of any supplied module shall have tolerance of plus 3% or above.
  2. The peak-power point voltage and the peak-power point current of any supplied module and/or any module string (series connected modules) shall not vary by more than 2 (two) per cent from the respective arithmetic means for all modules and/or for all module strings, as the case may be.
  3. The module shall be provided with a junction box with weather proof lid of sealed type and IP-65 rated.
  4.  I-V curves at STC shall be provided with the module.
  1. The module should have the following minimum information laminated inside the module.
  • Made in India (to be subscribed in words )
  • Company name /logo          
  • Model number (it should indicate the voltage and rated wattage of the module )
  • Serial number
  • Year of make
  1. Warranties:
  1. Material Warranty: 
  1. Material Warranty is defined as: The manufacturer should warrant the Solar Module(s) to be free from the defects and/or failures specified below for a period not less than twenty five (25) years from the date of commissioning of the system
  2. Defects and/or failures due to manufacturing 
  3. Defects and/or failures due to quality of materials 
  4. Non conformity to specifications due to faulty manufacturing and/or inspection processes. If the solar Module(s) fails to conform to this warranty, the manufacturer will repair or replace the solar module(s), at the Owners sole option.


  1. Performance Warranty: 
  1. The predicted electrical degradation of power generated not exceeding 20% of the minimum rated power over the 25 year period and not more than 10% after ten years period of the full rated original output. 

Module mounting structure (MMS) should be of anodised aluminium or Hot Dipped Galvanised Iron (HDGI), of prescribed Specifications given below, for mounting of SPV modules at site. The panel frame structure should be capable of withstanding a minimum wind speed load of 150 KM per hour, after grouting and installation. MMS should be sturdy & designed to assist SPV Modules to render maximum output. The hardware (fasteners) used for installation of SPV Modules & MMS should be of suitable Stainless Steel (SS 304). Each MMS should be with minimum four legs grouted on pedestals of minimum 300X300X250 mm with anchoring/ chipping & chemical sealing of foundation based on RCC roof. Foundation bolts of stainless /GI steel should be at least 300 mm long. 

Its size should be with reference to the specifications of the selected make SPV modules. Anti Theft Nut Bolts of SS (with washers) should be used for mounting modules for better theft proofing.

  1. Aluminium structure should meet the following minimum specifications:
  1. Structure Assembly Main Components:
  1. Purlin
  2. Leg & Base Plate
  3. Rafter (with cleat)


  1. Component Details:

1.       Purlin/Rafter (Design is indicative)












  • Cross section Length: 50mm, Cross section Width: 50mm, Thickness: 02mm
  • Component Length – As per PV modules table designed
  • Tolerance: ±5%



  • Cross sectional length – 135mm, Cross sectional width – 50mm, Thickness – 5mm
  • Tolerance: ±5%


2.       Leg & Base Plate

  1. Base Plate:
  • Cross sectional Length: 75mm, Cross sectional Height: 75mm, Thickness: 5mm
  • Component Length: 150mm with two holes on base area for fixing of J Bolts
  • Tolerance: ±5%
  1. Leg attached to base plate
  • Cross sectional length – 50mm, Cross sectional width – 50mm, Thickness – 5mm
  • Component Length – 3808mm ((or as per site requirement of tilt angle and may vary with the required height of structure) with two holes on bottom area for fixing with base plate and one hole on top are for fixing of Rafter
  • Tolerance: ±5%
    1. Hot Dipped Galvanised Iron (HDGI) structure should meet the following minimum specifications:

Rafter                          : 60mmX60mmX3.2mm

Purlin                           : 90mmX45mmX15mmX2.6mm

Vertical Post               : 60mmX60mmX3.2mm

Base Plate                   : 200mmX200mmX8mm

Top Plate                     : 176mmX176mmX8mm

  1. Foundation:

The CC foundation shall have to be designed on the basis of the weight of the structure with module and minimum wind speed of the site, i.e. 150 Km/hour.  Normally, each MMS should be with minimum four legs grouted on pedestals of proper size. However, for sheds CC work will not be required.Thestructure shall be grouted with fasteners with chemical sealing to withstand the required wind velocity. Angle of inclination shall be between 150 to 300,however,maybe changed as per site requirement.

  • CC Pillar size shall be: 300X300
  • For Pillars: Cement: Concrete: Sand Ratio :: 1:2:3
  • Screws shall be Grouted in the Slab of roof up to depth of 50 mm.
  • Lengths of rafter/Purlin may be changed as per site requirement.


Sufficient numbers of vertical post shall be provided so that the structure may not bent.




  1. Specifications For  Inverter/Power Conditioning Unit (PCU):

As SPV array produce direct current electricity, it is necessary to convert this direct current into alternating current and adjust the voltage levels to match the grid voltage. Conversion shall be achieved using an electronic Inverter and the associated control and protection devices. All these components of the system are termed the “Inverter”. In addition, the inverter shall also house MPPT (Maximum Power Point Tracker), an interface between Solar PV array & the Inverter, to the power conditioning unit/inverter should also be DG set interactive, if necessary. Inverter output should be compatible with the grid frequency. Typical technical features of the inverter shall be as follows:





Switching devices



The Rated Capacity of the Inverter shall not be less than the solar PV array capacity.


Microprocessor /DSP

Nominal Voltage

230V/415V as the case may be

Voltage range

Single Phase: Shall work from 180 Volts to 270 Volts;

Three Phase: Shall work from 180 Volts to 270 Volts per phase

Operating frequency/ range

50 Hz(47to52 Hz)

Grid Frequency Synchronization range

± 3 Hz or more (shall also compatible for Synchronization with DG Set)






DCvoltageripplecontentshallnotbe morethan1%.


  1. The inverters should be tested as per IEC standards/ as per latest MNRE Specification. The following criteria should be followed :
  2. The benchmarking efficiency criteria for the Grid tied ( central/string) inverter
    • At nominal voltage and full load is >95%
    • For load >25% is >92%.
  3. The benchmarking efficiency criteria for  Grid Tied PCU of capacity < 5KW: >85%and for capacity ≥ 5KW: ≥90%
  4. No load losses should not be more than 5%.




Casing protection levels

Degreeofprotection: MinimumIP-21 and 22for indoor useandIP65  certification for outdooruse


Shouldwithstandfrom-10to+50 degCelsius




Completely automatic  including  wake  up,  synchronization



Maximum power point tracker shall be integrated in the inverter to maximize energy drawn from the array.

MPPT   range must  be   suitable  to  individual array  voltages in power packs





Mains Under / Over Voltage



Over temperature

Short circuit


Surge voltage induced at output due to external source

Anti Islanding (for grid synch. mode)


Battery Under Voltage and Over Voltage


System Monitoring  Parameters

Inverter/PCU voltage & current

Mains Voltage, Current & Frequency

PV Voltage, Amps & KWH

System Mimic & Faults

Recommended LCDDisplayonFrontPanel

Accurate displays on the front panel:

DC input voltage

DC current

AC Voltage ( all 3 phases, in case of 3 phase)

AC current ( all 3 phases in case of 3 phase)

Ambient temperature

Instantaneous & cumulative output power

Daily DC energy produced

Battery Voltage (in case of Hybrid PCU)

Communication interface

RS 485 / RS 232

PCU shall also house MPPT (Maximum Power Point Tracker), an interface between Solar PV array to the power conditioning unit/inverter should also be DG set interactive.

Power Factor

> 0.9



Test Certificates

The inverter should be tested from the MNRE approved test centres / NABL /BIS /IEC accredited/authorised testing- calibration laboratories. In case of imported power conditioning units, these should be approved by international test houses.

  1. Three phase inverter shall be used with each power plant system (10kW and/or above) but in case of less than 10kW single phase inverter can be used as per site requirement.  The inverter of single phase shall be installed if grid supply is of single phase and that of three phase shall be installed if grid supply is of three phase.
  2. Inverter/PCU shall be capable of complete automatic operation including wake-up, synchronization & shutdown.
  3. The output of power factor of inverter/PCU is suitable for all voltage ranges or sink of reactive power, inverter should have internal protection arrangement against any sustainable fault in feeder line and against the lightning on feeder.   
  4. Built-in meter and data logger to monitor plant performance through external computer shall be provided (Providing Computer is not part of DNIT & is in the scope of user).
  5. Anti-islanding (Protection against Islanding of grid): The inverter/PCU shall have anti islanding protection in conformity to IEEE 1547/UL 1741/ IEC 62116/IS16169 or equivalent BIS standard.
  6. Successful Bidders/Supplier shall be responsible for galvanic isolation of solar roof top power plant (>100kWp) with electrical grid or LT panel.
  7. In Inverter/PCU, there shall be a direct current isolation provided at the output by means of a suitable isolating transformer. If Isolation Transformer is not incorporated with Inverter, there shall be a separate Isolation Transformer of suitable rating provided at the output side of inverter units for capacity more than 100 kW. 
  8. The inverter generated harmonics, flicker, DC injection limits, Voltage Range, Frequency Range and Anti-Islanding measures at the point of connection to the utility services should follow the latest CEA (Technical Standards for Connectivity Distribution Generation Resources) Guidelines.
  9. The inverter should comply with applicable IEC/ equivalent BIS standard for efficiency measurements and environmental tests as per standard codes IS/IEC 61683 and IEC 60068-2 (1,2,14,30)/ Equivalent BIS Std./EN50530,IEC 61727 (all clauses except clause 5.2.2). in case of clause 5.2.2, it should withstand the over/under frequency in the range 47 to 52 Hz.
  10. The MPPT units environmental testing should qualify IEC 60068-2 (1, 2, 14, 30)/ Equivalent BIS std. The junction boxes/ enclosures should be IP 65 (for outdoor)/ IP 54 (indoor) and as per IEC 529 specifications.



The battery should be Lithium Ferro Phosphate (LiFePO4) having given capacity. The other feature of battery should be:-






Battery Type



Working temperature range ( both for charging & discharging)

20-60 Deg. C


Minimum capacity of individual Cells

3.2V 40Ah


Type of Cell

Prismatic or Cylindrical


The Cell and Battery should be got tested as per IEC 62133-2012 or BIS specifications with MNRE/ NABL/IEC accredited test centre/ laboratory as per IEC/ BIS standard IEC 62133, IEC 61960 & UL1642: Safety of LiFePo4 battery


The Lithium Ferro Phosphate battery needs a very good “Battery Management System (BMS)” to ensure the proper charging and discharging of each cell of battery with proper protection of battery when temperature is reaching beyond battery permissible limits.


  1. The output power from SPV would be fed to the inverters/PCU which converts DC produced by SPV array to AC and feeds it into the main electricity grid after synchronization. In case of grid failure, or low or high voltage, solar PV system shall be out of synchronization and shall be disconnected from the grid. 4 pole isolation of inverter output with respect to the grid connection need to be provided. Solar Generation Meter(s) and bidirectional energy meter, as per HERC Net Metering Regulations should also be installed in the campus/building of beneficiary.
  2. The solar generation meter and Bi-directional meter along with CT/PT (if required) with Surge Protection Device (SPD) should be of 0.2S accuracy class is in the scope of bidder. For LT connection the accuracy shall be as per requirement of DISCOMs.
  3. CEA guideline 2013 for interconnecting solar power with Grid shall be followed.
  4. Certification of Islanding protection in the inverter from the manufacturer of the equipment shall be mandatory. This shall be arranged by the supplier from the manufacturer.
  5. Technical Standards for Interconnection:







Overall Conditions of Service

Reference to regulations

Conditions    for      Supply     of Electricity of Distribution Licensees




Reference to regulations

Central   Electricity  Authority (Grid   Standards)  Regulations




Applicable industry standards

IEC  standards/IS




Reference to  regulations, Chapter

III (General Safety Requirements)

Central Electricity  Authority

(Measures of  Safety and Electricity       Supply) Regulations, 2010 and subsequent amendments



Reference to regulations and additional conditions  issued  by the Commission.

Central   Electricity  Authority

(Installation & Operation of Meters) regulations 2006 and subsequent amendments




Harmonic current injections from a generating station shall not exceed  the   limits  specified  in IEEE 519

IEEE 519 relevant CEA (Technical Standards for Connectivity of the distributed generation   resource) regulations 2013 and subsequent amendments



Photovoltaic  system   must    be equipped with a  grid   frequency synchronization device, if the system is using synchronizer inherently built into the inverter than no  separate synchronizer is required.

Relevant CEA (Technical Standards for  Connectivity  of the distributed generation resources)  regulations   2013 and subsequent amendments.



The      voltage-operating     window should  minimize nuisance tripping and should be  under operating range of  80%   to  110% of the nominal connected voltage. beyond a clearing time of  2 seconds, the Photovoltaic system must isolate itself from the grid.



Operation  of   Photovoltaic system shouldn’t  cause  voltage flicker in excess of  the limits stated  in   IEC 61000  or   other  equivalent  Indian standards, if any

Relevant   CEA    regulations

2013   and   subsequent    if any,  (Technical  Standards for Connectivity of the distributed generation resource)



When the Distribution system frequency deviates outside the specified  conditions   (52 Hz   on upper  side and  47 Hz  on   lower side up to  0.2  sec), the Photovoltaic system  shouldn’t energize the  grid and should shift to island mode.



Photovoltaic system   should   not inject DC power more than 0.5% of full   rated output at the interconnection   point.   or    1%    of rated  inverter output  current  into distribution system under any operating conditions



While   the output of  the inverter is greater than  50%, a lagging power factor of  greater than 0.9   shall be maintained




The    Photovoltaic  system   in    the event  of  voltage  or   frequency variations must island/  disconnect itself  within  IEC   standard  on stipulated period




The invertershouldhavethefacilityto automaticallyswitchoff in case of overload or  overheating and should restart when  normal conditionsarerestored



For interconnecting Modules, Connecting modules and junction Boxes and junction boxes to inverter, DC copper cable of proper sizes shall be used. To connect inverter with AC panel aluminium cable of proper size shall be used. All the internal cables to be used in the systems shall be included in the cost while  100mtr. AC aluminium cable of proper size to be used to connect inverter/PCU to AC panel shall be included in the cost of the system.

Relevant   CEA    regulations 2013   and   subsequent    if any,  (Technical  Standards for Connectivity of the distributed generation resource)


  1. All switches and the circuit breakers, connectors should conform to IEC 60947, part I, II and III/ IS60947 part I, II and III.
  2. The change-over switches, cabling work should be undertaken by the bidder as part of the project.



The junction boxes shall be made up of FRP (Hensel or equivalent make)/PP/ABS with dust, water and vermin proof. It should be provided with proper locking arrangements.


Series / Array Junction Box (SJB/AJB) (whichever is required): All the arrays of the modules shall be connected to DCCB. AJB shall have terminals of bus-bar arrangement of appropriate size Junction boxes shall have suitable cable entry with suitable glanding arrangement for both input and output cables.  Suitable markings on the bus bars shall have to be provided to identify the bus bars etc. Suitable ferrules shall also have to be provided to identify interconnections. Every AJB should have suitable arrangement Reverse Blocking diode of suitable rating. Suitable SPD, suitable Isolation switches to isolate the DC input to Inverter has to be installed in AJB for protection purpose. Thus AJB should have DC isolator for disconnecting the arrays from inverter input. If in any case diodes, HRC Fuses, SPDs and isolators are installed in the string inverters, then there is need to install these again in AJB. If some of these safety gadgets are not installed in String Inverter it should be installed in AJB. Cable interconnection arrangement shall be within conduit pipe on saddles installed properly. Cable connection should be done in such a manner that fault findings if any, can be identified easily. The cables should be connected in such a manner that clamp meter can be comfortably inserted around the individual cables to measure the data like current, voltage etc. AJB should also be marked as A1, A2, & so on.


However, if the inverter/PCU is equipped with Junction Box, the cables may be connected directly to the ports provided in the inverter/PCU and no separate Junction Box is required.



Both AC & DC lines have suitable MCB/MCCB, Contractors, SPD, HRC Fuse etc to allow safe start up and shut down before & after string inverter installed in the system. String inverters should have protections for overload, surge current, high Temperature, over/ under voltage and over/ under frequency & reverse polarity. The complete operation process & safety instructions should printed on the sticker & suitably pasted on the near inverters.

Inverter should have safety measures to protect inverter from reverse short circuit current due to lightening or line faults of distribution network.

Inverter should be suitably placed in covered area on a suitable platform or wall mounted or concrete platform (on rubber mat) with complete safety measure as per norms. 


  • The combined wattage of all inverters should not be less than rated capacity of power plant under STC in KW.
  • Maximum power point tracker shall be integrated in the inverter to maximize energy drawn from the array



This shall consist of box shall consists of grid interphase panel of good quality FRP/ suitable powder coated metal casing. One Electronic Energy Meter (0.2S Class), ISI make, Single/Three Phase duly tested by DISCOMs (Meter testing Division) with appropriate CT (if required), of good quality shall have to be installed at suitable placed to measure the power generated from SPV Power Plant, as per HERC Net Metering Regulations. Proper rating MCCB & HRC fuse and AC SPDs shall be installed to protect feeders from the short circuit current and surges as per the requirement of the site. Operation AC Isolator Switch of Grid Connectivity should be such that it can be switched ON or OFF without opening the ACCB.


All cables should be of copper as per IS and should be of 650V/1.1 KV grade as per requirement.  All connections should be properly made through suitable lug/terminal crimped with use of suitable proper cable glands. The size of cables/wires should be designed considering the line loses, maximum load on line, keeping voltage drop within permissible limit and other related factors.  The cable/wire should be of ISI/ISO mark for overhead distribution. For normal configuration the minimum suggested sizes of cables are:

Module to module/AJB

: 4 sq mm (single core) DC Cable

AJBs to MJB/DCCB/Inverter/PCU

  • Up to capacity of 10 kWp Solar Plant, minimum 4sq mm (Single/Double core) DC Cable, with respect to current ratings of  designing
  • For capacity more than 10 kWp& up to 20 kWp Solar Plant, minimum 6sq mm (Single/Double core) DC Cable, with respect to current ratings of  designing
  • For capacity more than 20 kWp Solar Plant, minimum 10sq mm (Single/Double core) DC Cable, with respect to current ratings of  designing

Inverter to ACCB/Distribution board

AC Cable as per design & rating


The size & rating of the cables may vary depending on the design & capacity of SPV Power Plant.



All the cables should be laid in appropriate GI cable tray as per the requirement of the site, No cable should be laid directly on ground or wall cable tray should be laid such that there is gap of at least two inches above ground/roof/wall.


The bidder has to display a board at the project site mentioning the following:

  • Plant Name, Capacity, Location, Type of Renewable Energy plant (solar), Date of commissioning, details of tie-up with transmission and distribution companies, Power generation and Export FY wise.
  • Financial Assistance details from HAREDA/MNRE/Any other financial institution apart from loan. This information shall not be limited to project site but also be displayed at site offices/head quarter offices of the successful bidder
  • The size and type of board and display shall be approved by Engineer-in-charge before site inspection.
  • DANGER BOARDS: Danger boards should be provided as and where necessary as per IE Act. /IE rules as amended up to date.



It should be provided to isolate the system from Grid which should be outside of ACCB.

  1. AC Distribution Panel Board (DPB) shall control the AC power from PCU/ inverter, and should have necessary surge arrestors. Interconnection from ACDB to mains at LT Bus bar while in grid tied mode.
  2. All switches and the circuit breakers, connectors should conform to IEC 60947, part I, II and III/ IS60947 part I, II and III.
  3. The changeover switches, cabling work should be undertaken by the bidder as part of the project.
  4. All the Panel’s shall be metal clad, totally enclosed, rigid, floor mounted, air - insulated, cubical type suitable for operation on three phase / single phase, 415 or 230 volts, 50 Hz
  5. The panels shall be designed for minimum expected ambient temperature of 45 degree Celsius, 80 percent humidity and dusty weather.
  6. All indoor panels will have protection of IP54 or better. All outdoor panels will have protection of IP65 or better.
  7. Should conform to Indian Electricity Act and rules (till last amendment).
  8. All the 415  AC or 230 volts devices / equipment like bus support insulators, circuit breakers, SPDs, VTs etc., mounted inside the switchgear shall be suitable for continuous operation and satisfactory performance under the following supply conditions.

 Variation in supply voltage

+/- 10 %

Variation in supply frequency

+/- 3 Hz


  1. For systems of capacity 10 kWp and above, web based remote monitoring access of which shall also be provided to HAREDA software monitoring system with latest configuration. If needed access to MNRE shall also be provided.
  2. PV array energy production: Digital Energy Meters to log the actual value of AC/ DC voltage, Current & Energy generated by the PV system provided. Energy meter along with CT/PT should be of 0.2S accuracy class. For Hybrid there shall be provision in built in the PCU to measure generated solar energy as there is no option to install separate solar generation meter.
  3. String and array DC Voltage, Current and Power, Inverter AC output voltage and current (All 3 phases and lines), AC power (Active, Reactive and Apparent), Power Factor and AC energy (All 3 phases and cumulative) and frequency shall be monitored. 
  4. All instantaneous data shall be shown on the computer screen.
  5. Software shall be provided for USB download and analysis of DC and AC parametric data for individual plant. 
  6. Provision for instantaneous Internet monitoring and download of historical data shall be also incorporated.

Regarding the generated power consumption, in case of string inverter, priority need to given for internal consumption first and thereafter any excess power can be exported to grid.


The system should be provided with all necessary protections like earthing, Lightning, and grid anti- islanding as follows:

  1. Lightning And Over Voltage Protection:

The SPV Power Plant shall be provided with lightening and over voltage protection.  The principal aim in this protection is to reduce the over voltage to a tolerable value before it reaches the PV or other sub-systems components. The source of over voltage can be lightening or any other atmospheric disturbance. The Lighting Arrestor (LA) is to be made of 1¼" diameter (minimum) and 12 feet long GI spike on the basis of the necessary meteorological data of the location of the projects.  Necessary foundation for holding the LA is to be arranged keeping in view the wind speed of the site and flexibility in maintenance in future.  Each LA shall have to be earthed through suitable size earth bus with earth pits.  The earthing pit shall have to be made as per IS 3043. LA shall be installed to protect the array field, all machines and control panels installed in the control rooms. Number of LA shall vary with the capacity of SPV Power Plant & location. Number of LA should be in such a manner that total layout of solar modules should the effective coverage of LA’s.

For systems up to 10 kWp the lightening arrester shall of conventional type and for above 10 kWp systems it should be of  Early Streamer Emission (ESE) type.

  1. Earthing Protection:

Each array structure of the PV yard shall be grounded properly. In each array every module should be connected to each other with copper wires, lug teethed washers addition the lightening arrestor/masts shall also be provided inside the array field. Provision shall be kept for shorting and grounding of the PV array at the time of maintenance work. All metal casing/shielding of the plant shall be thoroughly grounded in accordance with Indian Electricity Act/IE rules as amended up to date. The earthing pit shall be made as per IS: 3043. All the array structures and equipments/control systems shall be compulsorily connected to the earth, separately. Number of earthling shall vary with the capacity of SPV Power Plant & location. G.I. /Copper strips should be used for earthling instead of G.I. wires. Adedoteyld&isidnel.NrfAlywiheiyfPVPwrt &. Earth resistance shall not be more than 5 ohms.

  1. Surge Protection:

Internal surge protection shall consist of three MOV type surge-arrestors connected +ve and –ve terminals to earth (via Y arrangement)

  1. Grid  Islanding:
  1. In the event of a power failure on the electric grid, it is required that any independent power-producing inverters attached to the grid turn off in a short period of time. This prevents the DC-to-AC inverters from continuing to feed power into small sections of the grid, known as “islands.”

Powered islands present a risk to workers who may expect the area to be unpowered, and they may also damage grid-tied equipment. The RooftopPV system shall be equipped with islanding protection. In addition to disconnection from the grid (due to islanding protection) disconnection due to under and over voltage conditions shall also be provided.

  1. A manual disconnect pole isolation switch beside automatic disconnection to grid would have to be provided at utility end to isolate the grid connection by the utility personnel to carry out any maintenance. This switch shall be locked, if required, by the utility personnel

The user have to take approval/NOC from the Concerned DISCOM for the connectivity, technical feasibility, and synchronization of SPV plant with distribution network and submit the same to HAREDA before commissioning of SPV plant, however the supplier have to extend all technical help to the user for preparing the documents required for getting the above clearance from DISCOMs.

Reverse power relay shall be provided by bidder (if necessary), as per the local DISCOM requirement.

The maximum capacity for interconnection with the grid at a specific voltage level shall be as specified in the Distribution Code/Supply Code and amended from time to time. Following criteria have been suggested for selection of voltage level in the distribution system for ready reference of the solar suppliers.

Plant Capacity

Connecting voltage

Up to 10 kWp

240V-single phase or 415V-three phase as per requirement of electric connection of the consumer

Above 10kWp and up to 100 kWp

415V – three phase

Above 100kWp

415V – three phase  or as per site requirement  based on the availability of grid level and as per DISCOM rules


Utilities may have voltage levels other than above, DISCOMS may be consulted before finalization of the voltage level and system shall be designed accordingly.


    1. Two sets of Engineering, electrical drawings and Installation and O&M manuals are to be supplied. Bidders shall provide complete technical data sheets for each equipment giving details of the specifications along with make/makes in their bid along with basic design of the power plant and power evacuation, synchronization along with protection equipment.
    2. Approved ISI and reputed makes for equipment be used.



The bidder shall take entire responsibility for electrical safety of the installation(s) including connectivity with the grid and follow all the safety rules & regulations applicable as per Electricity Act, 2003 and CEA guidelines etc. All work shall be carried out in accordance with the latest edition of the Indian Electricity Act and rules formed there under and as amended from time to time.


The quality of equipment supplied shall be controlled to meet the guidelines for  engineering design included in the standards and codes listed in the relevant ISI and other standards, such as :

  1. IEEE 928 Recommended Criteria for Terrestrial PV Power Systems.
  2. IEEE 929 Recommended Practice for Utility Interface of Residential and Intermediate PV Systems.
  3. IEEE 519 Guide for Harmonic Control and Reactive Compensation of Static Power Controllers.
  4. National Electrical NEPA 70-(USA) or equivalent national standard.
  5. National Electrical Safety Code ANSI C2- (USA) or equivalent national standard.
  6. JRC Specification 503 (Version 2.2 March 1991) or JPL Block V standard for PV modules.
  7. The inverter manufacturer should attach efficiency certificate from Independent Third party Testing laboratory i.e. IEC, TUV, SNL/ERTL & STQC.  PCU should confirm to IEC 61683 for efficiency measurements and IEC 60068 2 for environmental testing. MPPT unit should confirm to design qualification IEC 62093.
  8. IEC 62116  for Anti Islanding
  9. IEC 62109-1, IEC 62109-2 for safety