How to maintain your PV Station？
namkoo solar
PV stations require routine maintenance to ensure long hours of operation.
PV stations are maintained in 5 ways: (for distributed and centralised PV stations)
1. Maintenance of modules and stands
(1) The surface of the PV module should be kept clean and should be wiped with a dry or damp soft and clean cloth, the use of corrosive solvents or hard objects to wipe the PV module is strictly prohibited.In the case of irradiance lower than 200W/㎡ clean PV modules, should not use liquid with large temperature difference with the modules to clean the modules.
(2) PV modules should be inspected regularly, and PV modules should be adjusted or replaced immediately if the following problems are found.PV modules with crushed glass, scorched backsheets, visible colour changes; PV modules with air bubbles forming a connecting channel with the module edges or between any circuits; PV module junction boxes that are deformed, twisted, cracked or burnt and terminals that do not make good contact.
(3) The energised warning markings on the PV module must not be missing.
(4) For PV modules with metal frames, the frame and the bracket shall be well combined, with a contact resistance of not more than 4Ω between them, and the frame must be firmly grounded.
(5) When working under shadeless shading conditions, the difference in temperature between the outer surface of the same PV module (the area directly above the cell) should be less than 20°C under conditions where the solar irradiance is 500W/㎡ or more and the wind speed is not greater than 2m/s. Installed capacity greater than 50kWp photovoltaic power plant, should be equipped with infrared thermal imaging camera to detect the difference in temperature of the external surface of the photovoltaic module.
(6) Use a DC clamp-on ammeter to measure the input current of each PV module string connected to the same DC current sink under conditions of basically uniform solar radiation intensity, and the deviation should not exceed 5%.
(7) All bolts, welds and bracket connections of the bracket should be solid and reliable, and the anti-corrosion coating on the surface should not be cracked and fall off, otherwise it should be repainted in time.
2. Maintenance of the PV Combiner Box / DC Distribution Cabinet
(1) The DC Combiner Box should not be deformed, rusted, leaking or dusty, the safety warning signs on the outer surface of the box should be intact and undamaged, and the waterproof lock on the box should be flexible.
(2) The terminals in the DC Combiner Box should not be loose or corroded.
(3) The specifications of the high-voltage DC fuse in the DC Combiner Box should be in accordance with the design provisions.
(4) The insulation resistance of the positive pole to ground and the negative pole to ground of the DC output bus should be greater than 2 megohms.
(5) The DC output bus end is equipped with a DC circuit breaker, whose breaking function should be flexible and reliable.
(6) The lightning protector in the DC Combiner Box shall be effective.
(7) The connection between the DC output of the DC Distribution Cabinet and the DC input of the grid-connected host shall be stable and reliable.
3. Maintenance of the inverter
(1) The inverter structure and electrical connections should be kept intact and there should be no rust, corrosion, dust accumulation, etc. The heat dissipation environment should be good and there should be no large vibration and abnormal noise when the inverter is in operation.
(2) The cooling fans of the modules, reactors and transformers in the inverter shall start and stop on their own according to the temperature. There should be no large vibration and abnormal noise when the cooling fan is running, and any abnormal condition should be checked by power failure.
(3) Periodically disconnect the AC output side circuit breaker once and the inverter should stop feeding power to the grid immediately. (On-grid inverter)
(4) If the temperature of the DC bus capacitor in the inverter is too high or exceeds its service life, it should be replaced in time.
4. Maintenance of AC power distribution cabinet
(1) Ensure that the metal frame of the distribution cabinet is well connected to the base steel with galvanized bolts and that the anti-loosening low parts are complete.
(2) The identification device of the distribution cabinet indicating the number, name or operating position of the controlled equipment should be complete, and the number should be clear and neat.
(3) Busbar joints should be connected tightly, no deformation, no discharge blackening traces, no loose and damaged insulation, no rusting of fastening coupling bolts.
(4) The switch and main contacts in the distribution cabinet should be free of fusing traces, the arc extinguishing cover should be free of burning black and damage, the wiring screws should be tightened, and the cabinet should be cleaned of dust.
(5) Heat dissipation of low-voltage electrical appliances should be good, switching pressure plate should be lifted well, signal circuit signal lights, buttons, light signs, electric bells, torches, accident electric bell and other actions and signal display should be accurate.
(6) Test the insulation resistance value between the line and the line to ground of the line between the cabinet, screen, desk, box and plate, the feeder line must be greater than 0.5MΩ and the secondary circuit must be greater than 1MΩ.
5. Maintenance of the cable
(1)The cable should not be operated under overload, and the lead package of the cable should not show expansion and cracking.
(2)The parts of the cable at the inlet and outlet of the equipment should be well sealed, and there should not be holes with a diameter greater than 10㎜, otherwise they should be sealed with fireproof plugging mud walls.
(3)There should be no perforations, cracks and significant unevenness at the mouth of the cable protection steel pipe, the inner wall should be smooth, the metal cable pipe should not be seriously rusted, there should be no burrs, hard objects and rubbish, if there are burrs, file them and then wrap them with cable jacket and tie them tightly.
(4) When inspecting the indoor cable open trench, prevent damage to the cable and ensure that the bracket is grounded with good heat dissipation in the trench.
(5) The stakes along the direct buried cable line should be intact, no excavation on the ground near the path, ensure that there are no piles of heavy objects, building materials and temporary facilities on the ground along the path, no corrosive substances discharged, and ensure that the outdoor exposed ground cable protection facilities are intact.
(6) Ensure that the cover of the cable trench or cable well is intact, there should be no water or debris in the trench, ensure that the bracket in the trench should be firm and free from rust and looseness, and that the outer skin and armour of the armoured cable should not be seriously rusted.
(7) For multiple cables laid in parallel, check the current distribution and the temperature of the outer skin of the cable to prevent the cable from burning out the connection point due to poor contact.
(8) Ensure that the cable termination head is well grounded, the insulation sleeve is intact, clean and free from traces of flash discharge, and that the cable phase colour should be obvious.
Extra: Extreme weather maintenance
(1) If you encounter rain tripping, it is possible that the junction is not tight. If this type of situation occurs, you must deal with it after the rain has passed, use insulating tape to wrap the junction and then observe whether it trips, if the tripping phenomenon continues to occur, you should report to the maintenance office or the local electricity station.
(2) During thunderstorms, the air switch below the meter should be turned off to prevent damage to electrical equipment. When the thunderstorm is over, close the switch again.
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