On March 28, 2022, most of the DC cables in the solar power station will be arranged outdoors. The environment where the use scenario is located is very harsh. The cable materials will be selected according to the ultraviolet ray, ozone, severe temperature change and chemical corrosion degree such as acid and alkali in the environment. If ordinary cables are used, long time operation in harsh environment will lead to damage of cable sheath, even decomposition of cable insulation layer, resulting in short circuit of cables and fire accidents. Therefore, it is used in solar power stations PV cable It is absolutely necessary. Photovoltaic cables and ordinary cables go through different radiation steps. Radiation significantly improves the thermal, mechanical and chemical properties of cable insulation materials, and can withstand more ultraviolet radiation, severe temperature difference and chemical corrosion. New energy cable
If the high voltage of the system is 380, 450/750V photovoltaic AC cables shall be selected, and the cable with withstand voltage value greater than the high voltage of the system shall be selected to prevent the cable from being damaged by the high voltage.
For the connection between the inside and between the photovoltaic array, the rated current of the selected cable is 1.56 times of the large continuous current in the calculated photovoltaic cable.
For the connection of AC load, the rated current of photovoltaic cable selected is 1.25 times of the large continuous current in the calculated cable.
For the connection of inverter, the rated current of the selected cable is 1.25 times of the large continuous current in the calculated cable.
Consider the influence of temperature on cable performance. The higher the temperature is, the less the current carrying capacity of the cable will be. The cable should be installed in a ventilated and heat dissipating place as far as possible.
The high value of voltage drop shall not exceed 2%. There are many uncertain factors in the operation of DC circuit, which will lead to circuit grounding and make the whole system operate abnormally. It is generally related to the quality of the cable. If the insulation material is unqualified or the performance is grounded, the insulation layer is aging, and there are some damage defects, the system may be grounded. The invasion and tearing of outdoor mice and rabbits will also cause grounding hazards. In this case, cables with metal mesh must be used to ensure the safe use of photovoltaic cables.
