Major Components of Solar PV Power Plant
- Solar PV modules and array
- Module mounting structure
- Junction Boxes
- Power Conditioning Unit
- Cables and installation accessories
- Earthing and lightning protection
SOLAR PV MODULES AND ARRAY
- Only indigenous modules shall be used in the project. Solar module shall be Crystalline (Mono/Poly) (or) Thin Film (or) concentrator PV modules type. The peak power output of the PV Module shall be Maximum. Module Voc shall be minimum 24 V.
- The mechanical structure shall withstand gusts of wind / cyclonic wind up to 150km/hr from back side of the panel.
- PV modules must also qualify Salt Mist Corrosion Testing as per IEC 61701/IS61701
- Protective devices against surges at the PV module shall be provided. Low voltage drop bypass diodes shall be provided.
- PV modules used in solar power plants must be warranted for output wattage, which should not be less than 90% at the end of 10 years and 80% at the end of 25 years.
MOUNTING STRUCTURES
- The modules support structure shall be Mild Steel /hot dipped Galvanized (atleast 120 micron) Iron for holding the PV modules. The size of angle iron should not be less than 50x50x5 mm.
- Each panel frame structure shall be so fabricated as to be grouted on roof on its legs. The legs of the structure shall be fixed and grouted in the PCC foundation column made with 1:2:4 cement concrete. The foundation shall support SPV modules at a given orientation, absorb and transfer the mechanical loads to the ground properly and shall withstand maximum wind speed of 150 km/hr.
- All nuts and bolts should be made of good quality Stainless Steel.
- The array structure shall be so designed that it will occupy minimum space without sacrificing the output from the SPV panels.
- The minimum clearance of the lowest part of the module structure and the developed ground level shall not be less than 500 mm.
- The minimum clearance required from the parapet wall of the roof & in between row of panels is min 2 feet for cleaning the panels & servicing.
JUNCTION BOXES
- The junction boxes shall be dust proof, vermin and waterproof and made of FRP / Thermo Plastic. The terminals shall be connected to copper bus bar arrangement of proper sizes.
- The junction boxes shall have suitable cable entry points fitted with cable glands of appropriate sizes for both incoming and outgoing cables. Suitable markings shall be provided on the bus bar for easy identification and cable ferrules shall be fitted at the cable termination points for identification.
- Each main junction box shall be fitted with appropriate rating blocking diode. The junction boxes shall be of reputed make.
POWER CONDITIONING UNIT
- 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 “Power Conditioning Unit (PCU)”.
- In addition, the PCU shall also house MPPT (Maximum Power Point Tracker), an interface between Solar PV array & the Inverter, to maximize Solar PV array energy input into the System.
CABLES & ACCESSORIES
- All the cables shall be supplied conforming to IEC 60227/IS 694 & IEC 60502/IS 1554 shall be of 1.1 kV grade as per requirement. Only PVC copper cables shall be used.
- The size of the cables between array interconnections, array to junction boxes, junction box to PCU, PCU to AC Distribution Box etc shall be so selected to keep the voltage drop and losses to the minimum.
EARTHING AND LIGHTNING PROTECTION
- Earthing : The array structure of the PV yard shall be grounded properly using adequate number of earthing kits. All metal casing or shielding of the power plants shall be thoroughly grounded to ensure safety of the solar power plants.
- Lightning: The SPV power plants shall be provided with lightning &over voltage protection. The main aim in this protection shall be to reduce the over voltage to a tolerable value before it reaches the PV or other sub system components. The source of over voltage can be lightning, atmosphere disturbances etc