In recent years, under the support and guidance of relevant national policies, the solar photovoltaic power generation industry has been developing rapidly, and the installed capacity of photovoltaic power plants has been increasing year by year. However, because the development of domestic photovoltaic cable and its market promotion work is relatively late, in the construction and operation of photovoltaic power plant, photovoltaic power plant equipment connection cable is still using conventional cable. Because of the conventional cable in the design and manufacturing process does not take into account the complex and changing use of photovoltaic power plants and laying environment and other factors can not meet the requirements, resulting in the frequent occurrence of quality problems in photovoltaic power plants. In particular, the performance of the conventional cable itself can not meet the requirements of the power plant using the environment and the quality problems caused by particularly obvious. The special photovoltaic cables are designed in accordance with the complex and changing environment of photovoltaic power plants, and can meet the requirements of the laying and operation of photovoltaic power plants. In the photovoltaic power plant, especially the DC side of the use of special photovoltaic cable can effectively reduce the occurrence of quality problems.
In China, photovoltaic power plants are built throughout the country, which requires a large range of cable temperature rating, such as in the western and northern regions of China require cables to withstand lower temperatures, extreme low temperatures in individual areas can reach about -40 ℃, or even lower temperatures. In the eastern and southern regions of China, the surface temperature can easily reach more than +70 ℃, considering the conductor working temperature higher than the ambient temperature and heat volatilization, while considering the roof is not ventilated and poor heat dissipation effect of the bridge area extreme temperature is likely to exceed +90 ℃ or more, which requires the cable material temperature to meet the requirements of the power station to work in extreme temperatures.
Frequent changes in temperature and humidity have a direct impact on the aging of insulation and sheathing, especially in areas with large daily and annual temperature differences and humid and rainy areas, which have a greater impact on the aging performance of insulation and sheathing. Many power stations in China's fish and light complementary projects are built directly on top of fish ponds or water, requiring the cables to work normally under humid environment for a long time. Conventional cable performance does not take into account the impact of humidity and heat changes on the aging performance of materials, while the PV special cable is designed to take into account the impact of humidity and heat environment on the aging performance of insulation and sheathing materials factors, so that qualified PV cables can meet the requirements of PV power plants on temperature and humidity changes.
Photovoltaic power plants are longer hours of sunlight, the intensity of its exposure to sunlight irradiation is greater, and sunlight contains a variety of rays, especially ultraviolet light can accelerate the aging of the cable insulation and sheathing. Many of the cables of photovoltaic power plants are laid naked, solar modules to the converter box and even to the inverter cable is in most cases laid directly naked, which requires the cable must be able to withstand sunlight and ultraviolet radiation, to ensure that the sunlight and ultraviolet radiation under the vertical normal work for a long time. Therefore, qualified photovoltaic cables can work normally under sunlight and UV radiation for a long time, while conventional cables will accelerate the aging of their insulation and sheath under sunlight and UV radiation, resulting in the problem of reduced insulation performance or failure and reduced sheath protection.
Some photovoltaic power plants are established in special areas such as seaside and mudflats. These areas have a high salt spray content in the air. Some PV plants are sited in former salt farms, where the soil in the area has a high salt content. Cables used in these environmental conditions must have a high resistance to salt spray and acidity. Therefore, qualified photovoltaic cables are more resistant to salt spray and acid and alkali. Some photovoltaic power plants are located in areas with high ozone content, and ozone has a certain corrosive effect on the cable sheath, which means that the aging of the sheath is accelerated and affects the use of the cable. Conventional cables do not take into account the effect of ozone on the cable sheathing, while PV cables are designed with this effect in mind. Therefore, even in areas with high ozone content, photovoltaic cables can work properly for long periods of time.
The above-mentioned characteristics of photovoltaic cables can be applied to photovoltaic power plants under different environmental conditions to ensure that they can operate safely for a long time, which is difficult to achieve with conventional cables. Therefore, in the photovoltaic power plant construction project, especially some environmental special photovoltaic power plant construction project, the choice of photovoltaic cable instead of conventional cable can effectively ensure the long-term, stable operation of the power plant, thus ensuring a good long-term operational benefits of the power plant.