The working environment of photovoltaic (PV) power plants is very complex, and extreme weather conditions such as high or low temperature, humidity, salt spray, and heavy sand can test the reliability and environmental adaptability of PV systems.
As more and more photovoltaic power plants are built on the sea, islands, coastal beaches and saline-alkali areas, PV system power need to have higher resistance to salt spray and high humidity.
The biggest impact of salt spray and high humidity on the operation of photovoltaic projects is two to three years later. These extreme environments will seriously affect power electronic equipment such as photovoltaic modules, combiner boxes, brackets, cables and inverters.
Solar projects built along the coast are susceptible to high salinity and humid air, the biggest impact of salt spray and high humidity on modules is the PID effect.
High humidity environment is also easy to form water spots on the surface of solar photovoltaic modules, sodium ions in the glass will be precipitated on the glass surface, dust in the air will also be adsorbed on the glass surface, impurity ions dissolved in the water stains and sodium ions reduce the glass surface resistance.
Similarly, these salt mist or water vapor will also accumulate on the surface of the aluminum frame of the solar photovoltaic module, reducing the surface resistance of the aluminum frame.
In addition to sodium ions in salt spray, chloride ions can penetrate the protective layer on the metal surface and cause electrochemical reaction with the contact metal, resulting in product failure.
Since electrical products generally contain metal parts, salt spray and humid air will affect wires and cables, metal brackets, on grid photovoltaic system inverters and combiner boxes, etc., especially exposed metal parts.
In areas with large temperature difference and high humidity, such as beaches, mountains, and climates where water vapor is easy to evaporate and condense in spring and autumn, it is easy to cause condensation inside the equipment, resulting in internal moisture, causing short circuit, arcing and other faults.
In order to reduce the impact of salt spray and high humidity environment on PV systems, we must take more active protection and more active operation and maintenance of photovoltaic system design.
1. Equipment needs higher protection and high anti-corrosion level
For perc solar modules, it is necessary to test the product's anti-salt spray ability when used in salt spray and high humidity environments, and the anti-PID ability level needs to be higher.
The anti-PID test of photovoltaic modules can have stricter tests such as higher temperature, higher humidity, longer time, and more stringent surface coverage. Double-glass modules are usually used in high-humidity areas and water surface applications, which are considered to have better anti-PID performance.
The MC4 connectors and junction boxes of photovoltaic modules also require special waterproof and anti-corrosion tests.
2. There should be more operation and maintenance protection during the operation of the photovoltaic power station
For solar photovoltaic modules, the accumulated water, dust and salt mist on the surface will cause corrosion of the glass anti-reflection film and reduce the insulation resistance of the glass surface. Therefore, the glass surface should be kept as dry as possible to eliminate accumulated water.
The best way to eliminate water accumulation is to use a product called "Automatic Drainage Desilter". This product produced by solar products suppliers is made of the same material as the aluminum alloy frame and anodized on the surface, which can effectively prevent water accumulation and accumulation on the surface of the module. Ash.
For PV systems, regular inspection and maintenance during operation to prevent corrosion, refractory mud is required at the inlet and outlet of the collector or grid box to improve protection and prevent the entry of water vapor, especially to prevent the corrosion of foreign metals in the following two cases .
Photovoltaic modules – Metal fixtures are used during installation, and metal accessories such as stainless steel, aluminum, and zinc-iron alloys are artificially added to the frame of the solar photovoltaic module. As long as the material is different from the aluminum frame, it will cause the possibility of foreign metal corrosion.
PV systems - special care should be taken when using aluminum or zinc bolts to join stainless steel plates to prevent galvanic corrosion caused by the contact of dissimilar metals. Plastic gaskets can be added to isolate the two metals and prevent contact corrosion.
Salt spray and high humidity environments can corrode photovoltaic modules, power electronics and balance systems, seriously affecting the safety, reliability and long-term operation of projects.
Photovoltaic system projects should pay special attention to equipment selection, construction and operation and maintenance to improve the operating stability of photovoltaic power generation and reduce system errors.