Many households pay little attention to PV plants after they have been installed. In most cases, when PV systems are operating properly, they can provide us with a constant supply of electric energy without human intervention. But this is, after all, a set of power production equipment, containing numerous materials, if not pay attention to the daily maintenance, may make the power plant power generation reduced, or even cause fire and other dangers. Therefore, the daily maintenance of photovoltaic power plants should not be ignored, especially the following 6 things.
Cleaning of contaminants
The general life of PV modules is about 25 years. Regularly cleaning the module panels of bird droppings, leaves and other shading materials can ensure that the PV panels maximize exposure to sunlight. If you usually love cleanliness and have high requirements for power generation effect, you can also clean the modules by yourself, but you need to pay attention to the following points.
1. Generally choose to clean the modules in the morning or late afternoon. Do not stand less than 1 meter from the edge of the roof when cleaning.
2. Before cleaning the modules, you should check whether there is any abnormal power output in the monitoring records, analyze whether it may cause leakage, and check whether the connecting wires and related components of the modules are damaged or stuck.
3. Personnel cleaning components should wear appropriate work clothes and a hat to avoid scraping and injury. Hooks, straps, threads and other parts that can easily cause traction should be prohibited on clothes or tools.
4. It is strictly forbidden to clean PV modules under the weather conditions of high wind, heavy rain, thunderstorm or heavy snow. Winter cleaning should avoid flushing, and do not flush with cold water when the panel is very hot.
5. It is strictly forbidden to use hard and sharp tools or corrosive solvents and alkaline organic solvents to wipe the PV module, and forbid to spray the cleaning water to the module junction box, cable bridge, sink box and other equipment.
Maintenance of modules and brackets
1. PV module surface should be kept clean, should use dry or damp soft clean cloth to wipe the PV module, strictly forbid the use of corrosive solvents or hard objects to wipe the PV module. Should be in the irradiance lower than 200W/m2 clean photovoltaic modules, should not use and components with a large temperature difference of liquid cleaning components.
2. The charged warning mark on the PV module should not be lost.
3. 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 backsheet, obvious color changes.
-- PV modules with the presence of bubbles forming a connecting channel between the edge of the module or any circuit.
-- PV module junction box is deformed, twisted, cracked or burnt, and the terminals cannot make good contact.
4. Using metal frame photovoltaic module, the frame and the bracket should be well combined, the contact resistance between them is not more than 4Ω, the frame must be firmly grounded.
5. Use DC clamp-on ammeter to measure the input current of each PV module string connected to the same DC current sink under the condition that the solar radiation intensity is basically the same, and the deviation should not exceed 5%.
The maintenance of the converter box
1. DC converter box should not exist deformation, rust, water leakage, ash phenomenon, the safety warning signs on the outer surface of the box should be intact and undamaged, the waterproof lock on the box should be flexible to open and close.
2. DC converter box terminals should not appear loose, rust phenomenon.
3. The specifications of the high-voltage DC fuse in the DC bus bar should be in accordance with the design provisions.
4. The insulation resistance of the positive pole to ground and negative pole to ground of the DC output bus should be greater than 2 megohms.
5. DC output bus end with DC circuit breaker, its breaking function should be flexible and reliable.
6. The lightning protector in the DC busbar should be effective.
Maintenance of the inverter
1. The structure and electrical connection of the inverter should be kept intact, there should be no rust, dust accumulation, etc. The heat dissipation environment should be good, and there should be no large vibration and abnormal noise when the inverter is running.
2. The warning signs on the inverter should be complete and free from damage.
3. The cooling fan of the module, reactor and transformer in the inverter should start and stop by itself according to the temperature, and there should be no large vibration and abnormal noise when the cooling fan is running.
4. Periodically disconnect the AC output side (network side) circuit breaker once, and the inverter should stop feeding power to the grid immediately.
5. If the temperature of DC bus capacitor in the inverter is too high or exceeds its service life, it should be replaced in time.
Maintenance of the cable
1. The cable should be well blocked at the parts in and out of the equipment, and there should be no hole with a diameter greater than 10mm, otherwise it should be blocked with fire plugging mud wall.
2. The mouth of the cable protection steel pipe should not have perforations, cracks and significant unevenness, the inner wall should be smooth, the metal cable pipe should not be seriously rusted, there should be no burrs, hard objects, garbage, such as burrs, file light after wrapping with a cable jacket and tie.
3. The stakes along the direct burial cable line should be intact, no excavation on the ground near the path, to ensure that no piles of heavy objects, building materials and temporary facilities along the path on the ground, no corrosive material discharge, to ensure that the outdoor exposed ground cable protection facilities are intact.
4. 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 support in the trench should be firm, there is no rust, loose phenomenon, armored cable sheath and armor should not be seriously rusted.
5. Multiple cables laid side by side should 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.
Extreme weather maintenance
1. If you encounter rain tripping, it is possible that the junction is not tight, such as this type of situation, must be dealt with after the rain, available insulation tape wrapped around the junction, and then observe whether the trip, such as continued tripping phenomenon, should be reported to the maintenance center or the local electric station.
2. Thunderstorm days, the air switch below the meter should be closed to prevent damage to electrical equipment. When the thunderstorm is over, the switch will be closed again.
It is worth mentioning that we should not underestimate the cleaning and maintenance of home photovoltaic power station, cleaning after the power station can increase power generation by 5%-30%. Cleaning frequency in the wetter areas of the environment is generally 3 to 5 months cleaning 1 time, in the drier areas of the environment cleaning frequency is generally monthly cleaning 1 time.