The selection of cables in the photovoltaic system primarily considers the following factors:
1) Insulation performance of cable;
2) heat resistance and flame retardant performance of cable;
3) cable moisture-proof and light-proof;
4) Cable laying mode;
5) Type of cable core (copper core, aluminum core);
6) Cable size specifications.
The connection between the different components in the PV system, because of the different environment and requirements, the selected solar cable manufacturer is also different. The technical requirements of different connection parts are listed as follows:
1) Connection between elements: must be tested, heat resistant 90℃, acid, chemical, moisture-proof, anti-insolation. The cable is used outdoors and directly exposed to sunlight. The DC part of the PV system should be equipped with cables that are resistant to oxidation, high temperature and ultraviolet rays.
2) The connection between the phalanx and the phalanx: it can be open or buried in the ground, needing moisture-proof and anti-insolation. It is recommended to install the pipe through the pipe, and the pipe must be heat resistant to 90 ° C.
3) The connection between the square array and the inverter: must be tested, heat resistant 90℃, acid, chemical, moisture-proof, anti-exposure. The cable is used outdoors and directly exposed to sunlight. The DC part of the PV system should be equipped with cables that are resistant to oxidation, high temperature and ultraviolet rays.
The cable size specification design must obey the following principles:
1) For AC load connection, the rated current of the selected cable is 1.25 times of the maximum continuous current in the estimated cable. For the connection of the inverter, the rated current of the selected cable is 1.25 times of the maximum continuous current in the estimated cable. For the connection between the square array and the square array, the rated current of the selected cable is 1.56 times of the maximum continuous current in the estimated cable.
2) Examine the influence of temperature on cable performance.
3) Consider a voltage drop of no more than 2%.
4) The appropriate cable size selection is based on two factors, current strength and circuit voltage loss. The complete computation formula is: line loss = current x circuit bus length x cable voltage factor (available from cable maker).