1、 The selection of cables in photovoltaic systems mainly considers the following factors:
● Insulation performance of cables;
● The heat resistance and flame retardancy of cables;
● Moisture and light resistance of cables;
● The laying method of cables;
● Types of cable cores (copper core, aluminum core);
● The size and specifications of the cable.
2、 The connection between different components in a photovoltaic system requires different cables due to varying environments and requirements. The following lists the technical requirements for different connection parts
1) Connection between components
Must undergo UL testing, with a heat resistance of 90 ℃, acid resistance, chemical resistance, moisture resistance, and sun exposure resistance.
2) Wiring between battery and inverter
Multiple strand flexible cords that have passed UL testing can be used, or welding machine cables that have passed UL testing can be used.
3) Connections within and between matrices
It can be outdoors or buried underground, requiring moisture and sun protection. It is recommended to install through pipes, and the pipes must be heat-resistant to 90 ℃.
4) Indoor wiring (dry environment)
Short DC connections can be used.
3、 The design of cable size specifications must follow the following principles:
● The short distance DC connection between the battery and indoor equipment selects the rated current of the cable as 1.25 times the calculated continuous current of the cable.
● The rated current of the selected cables for the connections within and between the arrays is 1.56 times the maximum continuous current in the calculated cables.
● The rated current of the selected cable for the connection of the AC load is 1.25 times the maximum continuous current in the calculated cable.
● The rated current of the selected cable for the connection of the inverter is 1.25 times the maximum continuous current in the calculated cable.
● Consider the impact of temperature on the performance of cables.
● Consider not exceeding a voltage drop of 2%.
● The appropriate selection of cable diameter is based on two factors: current intensity and circuit voltage loss. The calculation formula is:
Line loss=current x circuit bus length x cable voltage factor (available from cable manufacturer)
