Photovoltaic cables will inevitably age during long-term outdoor use. Timely and accurate detection and treatment of aging problems are important links to ensure the safe and stable operation of photovoltaic systems. Before detecting the aging of photovoltaic cables, it is necessary to first conduct a comprehensive observation of the cable laying environment to check whether the cables are exposed to direct sunlight, high temperature, humidity or corrosive gas environments for a long time. These factors may accelerate the aging of cables. At the same time, check whether there is a risk of mechanical damage at the installation location of the cable, such as whether it is squeezed by sharp objects or whether it is worn due to wind shaking. Preliminary judgment of possible causes of aging provides direction for subsequent detection.
Appearance inspection is the basic method for detecting the aging of photovoltaic cables. Carefully check the state of the outer sheath of the cable. The aged cable sheath usually has a rough surface, loses its gloss, cracks, or becomes hard and brittle. In severe cases, the sheath may peel off. Press the sheath lightly with your fingers. If the elasticity decreases significantly and it cannot quickly return to its original state after pressing, it also indicates that the sheath has aged. In addition, the sealing of the cable joints should be checked. Aging may cause the sealant at the joints to crack and harden, lose its waterproof and moisture-proof function, and then cause oxidation and rust of the internal core wire.
Insulation performance testing can deeply judge the degree of aging inside the photovoltaic cable. Use an insulation resistance tester to measure the insulation resistance of the cable. The insulation resistance value of the aged cable will be significantly reduced due to the degradation of the insulation material performance. During the test, make sure that both ends of the cable are completely disconnected from the circuit to avoid interference from other equipment on the test results. For longer cables, the test can be carried out in sections to more accurately locate the aging area. If the test finds that the insulation resistance value is lower than the normal range, it means that the insulation layer of the cable has aged, and it is necessary to further analyze the severity of the aging and take corresponding measures.
Core wire status detection is a key link in judging the aging of photovoltaic cables. When the outer sheath shows signs of aging, it is necessary to peel off part of the sheath to check the condition of the internal core wire. An oxide layer may appear on the surface of the aged core wire, the color becomes darker or even black, and the original bright metallic luster disappears. Use a tool to gently scrape the surface of the core wire. If powdery substances or obvious scratches are easy to appear, it means that the core wire has been severely oxidized and aged. In addition, the flexibility of the core wire needs to be checked. The aged core wire will become stiff and prone to breakage when bent, which will directly affect the conductivity and mechanical strength of the cable.
For different degrees of photovoltaic cable aging problems, corresponding treatment measures should be taken. For slightly aged cables, if only the sheath surface has slight cracks or loses its gloss, and the insulation resistance and core wire status are basically normal, the cable laying environment can be optimized first, such as adding sunshade protection, improving ventilation conditions, removing surrounding corrosive substances, etc. At the same time, strengthen daily monitoring, shorten the detection cycle, and observe the aging development trend. If necessary, a special cable protective agent can be applied to the surface of the sheath to enhance its anti-aging ability and extend its service life.
When the photovoltaic cable is seriously aged, such as large-area cracks on the sheath, a significant decrease in insulation resistance, or obvious oxidation of the core wire, it must be replaced in time. When replacing cables, select photovoltaic cables with the same specifications and models as the original cables to ensure that their performance parameters meet the requirements of the photovoltaic system. In the process of laying new cables, strictly follow the installation specifications to avoid premature aging of new cables due to improper laying. At the same time, the joints of the cables should be professionally treated to ensure good sealing and prevent moisture and moisture from invading. After the replacement is completed, the insulation and conductivity tests need to be re-performed to ensure that the new cables are installed in place and work properly.
Preventing photovoltaic cable aging is a fundamental measure to reduce aging problems. In the design stage of the photovoltaic system, high-quality photovoltaic cables with excellent weather resistance, UV resistance, high and low temperature resistance should be selected according to the installation environment to avoid choosing inferior cables for cheapness. During the installation process, reasonably plan the laying path of the cables to avoid mechanical damage and adverse environmental factors, and take good measures to fix and protect the cables. In daily operation, regularly inspect and maintain the photovoltaic cables, clean the dust and debris on the cable surface in time, check the changes in the laying environment, and deal with problems in time, so as to control the aging risk in the bud and ensure the safe and reliable operation of the photovoltaic system.
