1. Maintenance of photovoltaic modules and supports
(1) The surface of photovoltaic modules shall be kept clean. Photovoltaic modules shall be wiped with dry or wet, soft and clean cloth. It is strictly prohibited to wipe photovoltaic modules with corrosive solvents or hard objects. The photovoltaic modules shall be cleaned when the irradiance is lower than 200W/m2, and the liquid with large temperature difference from the module shall not be used to clean the module.
(2) Photovoltaic modules shall be inspected regularly. If the following problems are found, the photovoltaic modules shall be adjusted or replaced immediately.
——There are glass crushing, back plate scorching and obvious color changes in photovoltaic modules;
——There are bubbles in the photovoltaic module that form a communication channel with the edge of the module or any circuit;
——The junction box of photovoltaic module is deformed, twisted, cracked or burned, and the terminal blocks cannot be well contacted.
(3) Live warning signs on photovoltaic modules shall not be lost.
(4) For photovoltaic modules with metal frame, the frame and support shall be well combined, the resistance between them shall not be greater than 4Ω, and the frame must be firmly grounded.
(5) When working without shadow, the temperature difference on the outer surface of the same photovoltaic module (the area directly above the battery) shall be less than 20 ℃ under the condition that the solar irradiance is more than 500W/m2 and the wind speed is not more than 2m/s. The photovoltaic power station with installed capacity greater than 50kWp shall be equipped with infrared thermal imager to detect the temperature difference on the outer surface of photovoltaic modules.
(6) Use DC clamp-on ammeter to measure the input current of each photovoltaic module string connected to the same DC combiner box under the condition that the solar radiation intensity is basically the same, and the deviation shall not exceed 5%.
(7) All bolts, welds and support connections of the support shall be firm and reliable, and the anti-corrosion coating on the surface shall not crack or fall off, otherwise it shall not be brushed in time.
2. Maintenance of combiner box in photovoltaic power station
(1) The DC combiner box shall be free of deformation, corrosion, water leakage and ash accumulation. The safety warning signs on the external surface of the box shall be complete without damage, and the waterproof lock on the box shall be opened and closed flexibly.
(2) Each wiring terminal in the DC combiner box shall not be loose or rusted.
(3) The specification of high voltage DC fuse in DC combiner box shall meet the design requirements.
(4) The insulation resistance of positive pole to ground and negative pole to ground of DC output bus shall be greater than 2 megohm.
(5) The DC circuit breaker equipped at the DC output bus end shall have flexible and reliable breaking function.
(6) Lightning arrester in DC combiner box shall be effective.
3. Maintenance of DC distribution cabinet in photovoltaic power station
(1) The DC distribution cabinet shall be free of deformation, corrosion, water leakage and ash accumulation. The safety warning signs on the external surface of the box shall be complete without damage, and the waterproof lock on the box shall be opened flexibly.
(2) Each wiring terminal in the DC distribution cabinet shall not be loose or rusted.
(3) The insulation resistance of positive pole to ground and negative pole to ground of DC output bus shall be greater than 2 megohm.
(4) The connection between DC input interface of DC distribution cabinet and combiner box shall be stable and reliable.
(5) The connection between DC output of DC distribution cabinet and DC input of grid-connected host shall be stable and reliable.
(6) The DC circuit breaker of DC distribution cabinet shall operate flexibly and have stable and reliable performance.
(7) The lightning arrester configured at the output side of DC bus shall be effective.
4. Maintenance of inverter in photovoltaic power station
(1) The structure and electrical connection of the inverter shall be complete without corrosion, dust accumulation, etc. The heat dissipation environment shall be good, and there shall be no large vibration and abnormal noise during the operation of the inverter.
(2) The warning signs on the inverter shall be complete without damage.
(3) The cooling fans of modules, reactors and transformers in the inverter shall start and stop automatically according to the temperature, and there shall be no large vibration and abnormal noise during the operation of the cooling fans. In case of any abnormality, the power shall be cut off for inspection.
(4) Disconnect the AC output side (grid side) circuit breaker once regularly, and the inverter shall immediately stop feeding to the grid.
(5) If the temperature of DC bus capacitor in the inverter is too high or exceeds the service life, it shall be replaced in time.
5. Maintenance of AC distribution cabinet in photovoltaic power station
(1) Ensure that the metal frame of the distribution cabinet are well connected with galvanized bolts applied to the foundation section steel, and the anti loose parts are complete.
(2) The identification devices indicating the number, name or operation position of the controlled equipment in the distribution cabinet shall be complete, and the number shall be clear and neat.
(3) The bus joint shall be connected tightly without deformation, blackening trace due to discharge, the insulation shall be free of looseness and damage, and the fastening connecting bolts shall be free of rust.
(4) The trolley and withdrawable complete power distribution cabinet shall be pushed and pulled flexibly without jamming and collision. The center lines of moving contacts and static contacts shall be consistent and the contacts shall be in close contact.
(5) The switches and main contacts in the distribution cabinet shall be free of melting marks, and the arc extinguishing chamber shall be free of blackening and damage. Tighten all wiring screws and clean the dust in the cabinet.
(6) Take each cabinet out of the drawer and fasten each wiring terminal. Check the installation and wiring of current transformer, ammeter and watt hour meter, the handle operating mechanism shall be flexible and reliable, fasten the incoming and outgoing lines of circuit breaker, and clean the dust in the switch cabinet and the outgoing line behind the distribution cabinet.
(7) The heat dissipation of low-voltage electrical heating objects shall be good, the switching pressing plate shall be in good contact, and the action and signal display of signal lamps, buttons, light plates, electric bells, torches, accident clocks, etc. in the signal circuit shall be accurate.
(8) Check the insulation resistance between lines and between lines to ground of cabinets, screens, platforms, boxes and panels lines. The feeder line must be greater than 0.5 MΩ and the secondary circuit must be greater than 1 MΩ.
6. Transformer maintenance of photovoltaic power station
(1) The thermometer of the transformer shall be intact, the oil temperature shall be normal, the oil level of the oil conservator shall correspond to the ambient temperature, and there shall be no leakage and oil leakage at all parts. The load, cooling conditions and seasons of each transformer may be different. The transformer in operation shall not be based on the fact that the oil temperature of the above layer does not exceed the allowable value, but also be compared with the last oil temperature according to previous operation experience and under the above conditions.
(2) The oil level of the casing shall be normal, and there shall be no damage, crack, serious oil stain, discharge trace and other abnormal phenomena outside the casing, and the oil quality shall be transparent and slightly yellow, which can judge the oil quality. The oil level shall meet the standard line of ambient temperature. If the oil level is too low, check whether the transformer leaks oil, etc. If the oil level is too high, check the service condition of the cooling device and whether there is internal fault.
(3) The transformer sound shall be normal, and there is generally uniform buzzing electromagnetic sound during normal operation. If the sound is abnormal, carefully check it, make correct judgment and deal with it immediately.
(4) The transformer lead shall be free from strand breakage, the connector shall be free from overheating and discoloration or the thermometer shall not be melted (discolored), the respirator shall be intact, and the discoloration degree of silicone glue shall not exceed 3/4.
(5) The tapping position and power indication of the excitation voltage regulating tap changer shall be normal, there shall be no gas in the gas relay, and the transformer shell grounding and iron core grounding shall be intact.
(6) In case of bad weather, special inspection shall be focused. In case of strong wind, check whether the leads swing violently and whether the sag is sufficient. There shall be no sundries at the transformer top cover and bushing leads. In heavy snow days, all contacts shall not melt or discharge immediately after falling snow. Whether there is spark discharge, etc. in each part should be checked in heavy foggy day.