How to maintain the power station well, we will introduce it to the customers who install it:
Maintenance of components and brackets
1. The surface of photovoltaic modules should be kept clean. Use dry or damp soft and clean cloth to wipe photovoltaic modules. It is strictly forbidden to use corrosive solvents or hard objects to wipe photovoltaic modules. PV modules should be cleaned when the irradiance is lower than 200W/㎡, and it is not advisable to use liquids with a large temperature difference from the modules to clean the modules.
2. Photovoltaic modules should be checked regularly, and if the following problems are found, the photovoltaic modules should be adjusted or replaced immediately.
——The photovoltaic module has broken glass, scorched backplane, and obvious color change;
- the presence of air bubbles in the photovoltaic module that form a communication channel with the edge of the module or any circuit;
——The photovoltaic module junction box is deformed, twisted, cracked or burned, and the terminals cannot be in good contact.
3. The live warning signs on the photovoltaic modules must not be lost.
4. For photovoltaic modules with metal frame, the frame and bracket should be well combined, the contact resistance between the two should not be greater than 4Ω, and the frame must be firmly grounded.
5. When working without shadows, when the solar irradiance is above 500W/㎡ and the wind speed is not greater than 2m/s, the temperature difference on the outer surface of the same photovoltaic module (the area directly above the battery) should be less than 20℃. Photovoltaic power plants with an installed capacity greater than 50kWp should be equipped with infrared thermal imaging cameras to detect temperature differences on the outer surface of photovoltaic modules.
6. Use a DC clamp ammeter to measure the input current of each PV module string connected to the same DC combiner box under the condition that the solar radiation intensity is basically the same, and the deviation should not exceed 5%.
7. All bolts, welds and bracket connections of the bracket should be firm and reliable, and the anti-corrosion coating on the surface should not crack and fall off, otherwise it should be brushed in time.
Maintenance of the combiner box
1. The DC combiner box must not be deformed, corroded, leaked, or deposited. The safety warning signs on the outer surface of the box should be complete and undamaged, and the waterproof lock on the box should be flexible to open and close.
2. It is best not to loosen or corrode the terminals in the DC combiner box.
3. The specifications of the high-voltage DC fuses in the DC combiner box must meet the design regulations.
4. The insulation resistance of the positive pole to the ground and the negative pole to the ground of the DC output bus should be greater than 2 megohms.
5. The DC circuit breaker equipped at the DC output bus terminal must be flexible and reliable in its breaking function.
6. The lightning arrester in the DC combiner box should be effective.
Maintenance of DC distribution cabinet
1. The DC power distribution cabinet must not be deformed, corroded, leaked, or deposited. The safety warning signs on the outer surface of the box should be complete and undamaged, and the waterproof lock on the box should be opened flexibly.
2. Do not loosen or corrode the terminals in the DC distribution cabinet.
3. The insulation resistance of the positive pole to the ground and the negative pole to the ground of the DC output bus should be greater than 2 megohms.
4. The connection between the DC input interface of the DC power distribution cabinet and the combiner box should be stable and reliable.
5. The connection between the DC output of the DC power distribution cabinet and the DC input of the grid-connected host should be stable and reliable.
6. The action of the DC circuit breaker of the DC power distribution cabinet should be flexible, and the performance should be stable and reliable.
7. The lightning arrester configured on the output side of the DC bus should be effective.
Maintenance of AC power distribution cabinet
1. Ensure that the metal frame of the power distribution cabinet and the basic steel are well connected with galvanized bolts, and the anti-loosening parts are complete.
2. The identification devices of the power distribution cabinet indicating the number, name or operation position of the controlled equipment should be complete, and the number should be clear and neat.
3. The busbar joints should be connected tightly, without deformation, without blackening marks of discharge, without loose and damaged insulation, and without rust on the tightening bolts.
4. The push-pull of the handcart and the withdrawable complete power distribution cabinet should be flexible, and there should be no jamming and collision phenomenon. The center lines of the dynamic and static contacts should be consistent with the static contacts, and the contacts should be in close contact.
5. The switches and main contacts in the power distribution cabinet have no burning marks, and the arc extinguishing cover has no burning black and damage. Tighten the wiring screws and clean the dust in the cabinet.
6. Take out each sub-switch cabinet from the drawer, and fasten each terminal. Check the installation and wiring of current transformers, ammeters, and watt-hour meters. The handle operating mechanism should be flexible and reliable. Tighten the incoming and outgoing wires of the circuit breaker, and clean the dust in the switch cabinet and the lead wires behind the power distribution cabinet.
7. The heat dissipation of low-voltage electrical appliances should be good, the switching pressure plate should be released well, and the signal lights, buttons, light signs, electric bells, torches, accident electric bells and other actions and signals of the signal circuit should be displayed accurately.
8. Insulation resistance value between lines and line-to-ground of lines between inspection cabinets, screens, platforms, boxes and panels must be greater than 0.5MΩ for feeder lines and 1MΩ for secondary circuits
Inverter maintenance
1. The inverter structure and electrical connection should be kept intact, and there should be no rust, dust accumulation, etc., and the heat dissipation environment should be good. When the inverter is running, there is large vibration and abnormal noise, which needs to be adjusted in time.
2. The warning signs on the inverter should be complete and not damaged.
3. The cooling fans of the modules, reactors and transformers in the inverter should start and stop automatically according to the temperature. The cooling fans should not have large vibration and abnormal noise during operation.
4. Disconnect the circuit breaker on the AC output side (grid side) once regularly, and the inverter should immediately stop feeding power to the grid.
5. If the temperature of the DC bus capacitor in the inverter is too high or exceeds the service life, it should be replaced in time.
Maintenance of cables
1. The cable should not run under overload, and the lead package of the cable should not be expanded or cracked.
2. The parts of the cables entering and leaving the equipment should be sealed well, and there should be no holes larger than 10mm in diameter, otherwise they should be blocked with fireproof mud walls.
3. In the place where the cable has too much pressure and tension on the equipment shell, the supporting point of the cable should be intact.
4. 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 severely corroded, and there should be no burrs, hard objects, and garbage. If there are burrs, use the cable after filing. The jacket is wrapped and tied.
5. The accumulations and garbage in the outdoor cable well should be cleaned up in time. If the cable sheath is damaged, it should be dealt with.
6. When checking the open ditch of the indoor cable, it is necessary to prevent damage to the cable and ensure that the bracket is grounded and the heat dissipation in the ditch is good.
7. The stakes along the direct buried cable line should be intact, and the ground near the path should not be excavated to ensure that no heavy objects, building materials and temporary facilities are stacked on the ground along the path, and no corrosive substances are discharged to ensure that the outdoor exposed ground cable protection facilities are intact.
8. Ensure that the cover plate of the cable trench or cable well is intact, there should be no water or debris in the trench, ensure that the support in the trench should be firm, free of corrosion and loosening, and the sheath and armor of the armored cable should not be severely corroded.
9. For multiple cables laid in parallel, the current distribution and the temperature of the cable sheath should be checked to prevent the cables from burning out the connection points due to poor contact.
10. Ensure that the cable terminal is well grounded, the insulating sleeve is intact, clean, and has no traces of flashover discharge, and ensure that the color of the cable should be obvious.