The Need To Replace Conventional Cables with Photovoltaic Cables in Old Solar Power Stations

In recent years, under the support and guidance of relevant national policies, the solar photovoltaic power generation industry has developed rapidly, and the installed capacity of solar power plants has increased year by year. However, due to the relative lag in the research and development and marketing of domestic photovoltaic cables, in the construction and operation of solar power plants, the connecting cables of solar power plants still use conventional cables. Because conventional cables do not consider the complex and changeable environment of photovoltaic power plant use and laying in the design and manufacturing process, they cannot meet the requirements of use, resulting in frequent quality problems of photovoltaic power plants. In particular, the quality problems caused by the performance of conventional cables themselves cannot meet the requirements of the power station environment. Photovoltaic cables are designed according to the complex and changeable operating environment of photovoltaic power plants, and can meet the laying and operation requirements of photovoltaic power plants. The use of photovoltaic cables in photovoltaic power plants, especially the DC side, can effectively reduce the occurrence of quality problems.

Photovoltaic power plants are built all over China, which requires a wide range of temperature resistance of cables. For example, in western and northern China, cables need to withstand lower temperatures. In some areas, extreme low temperatures can reach -40°C. even lower temperatures. In eastern and southern China, the surface temperature can easily reach above +70℃. Considering that the working temperature of the conductor is higher than the ambient temperature and generates heat, it can be considered that the temperature in the unventilated area on the roof is extreme, and the heat dissipation effect of the bridge is not good. Above +90℃, this requires the material temperature of the cable to meet the requirements of the station working in extreme temperatures.

Frequent changes in temperature and humidity have a direct impact on the aging of insulation and sheathing of materials, especially in areas with large daily temperature differences, large annual temperature differences and humid and rainy areas, which have a greater impact on insulation and aging properties of materials. Many power stations in my country's fish-optical complementary projects are directly built in fish ponds or on the water surface, requiring cables to work normally in a humid environment for a long time. The performance of traditional cables does not take into account the effect of moisture and heat changes on the aging properties of materials. The design of photovoltaic cables takes into account factors that affect the aging properties of insulation and sheathing materials. Therefore, only qualified photovoltaic cables can meet the requirements of photovoltaic power plants. Changes in temperature and humidity are required.

Photovoltaic power plants have long sunshine hours and stronger resistance to sunlight. Sunlight contains a variety of rays, especially ultraviolet rays, which will accelerate the aging of the insulation and sheath of the cable. Most PV plants have cables that are barely laid. The solar modules connected to the combiner boxes, and even the cables connected to the inverters are mostly barely laid. This requires that the cable can withstand sunlight and ultraviolet radiation, and can ensure that it can work normally for a long time under sunlight and vertical radiation. Therefore, qualified photovoltaic cables can work normally for a long time under the conditions of sunlight and ultraviolet radiation. However, under the conditions of sunlight and UV exposure, the insulation and jacket of conventional cables will age rapidly, resulting in reduced insulation performance or failure.

Some photovoltaic power stations are built in special areas such as seaside and beach. These areas have high levels of salt spray in the air. Some photovoltaic power stations are located in the original salt field, and the soil salt content is relatively high. Cables used in the above environmental conditions must have strong resistance to salt spray and acid and alkali. Therefore, qualified photovoltaic cables are more resistant to salt spray and acid and alkali. The ozone content of some photovoltaic power stations is high, and ozone has a certain corrosive effect on the cable sheath, which accelerates the aging of the sheath and affects the use of the cable. Conventional cables do not take into account the royal influence on the cable jacket, which is considered in PV cable design.

The above characteristics of photovoltaic cables can be applied to photovoltaic power plants under different environmental conditions to ensure long-term safe operation, while conventional cables are difficult to achieve. Therefore, in the construction of photovoltaic power stations, especially some special photovoltaic power station construction projects, the use of photovoltaic cables instead of conventional cables can effectively ensure the long-term stable operation of the power station, thereby ensuring the benefits of good long-term operation of the power station.