Considerations for cable selection in photovoltaic systems

The design method of cable selection in photovoltaic system covers factors that should be considered when selecting cables in photovoltaic systems, how to choose suitable cables in different environments, and the principles that should be followed in cable size design.

First, the selection of cables in photovoltaic systems mainly considers the following factors:

1. The insulation performance of the cable;

2. The heat and flame resistance of the cable;

3, the cable is moisture-proof and light-proof;

4. The laying method of the cable;

5, the type of cable core (copper core, aluminum core);

6, the size of the cable specifications.

Second, the connection between different components in the photovoltaic system, due to different environments and requirements, the selected cable is also different. The technical requirements for the different connection sections are listed below:

1) Connection between components and components

UL test must be carried out, heat-resistant 90 ° C, acid-proof, chemical-proof, moisture-proof, anti-exposure.

2) Wiring between battery and inverter

You can use a multi-strand cord that has passed the UL test, or a welder cable that passes the UL test.

3) The connection between the square matrix and the square matrix

It can be used in the open air or buried in the ground, requiring moisture and sun exposure. It is recommended to install the tube and the tube must be heat resistant to 90 °C.

4) Indoor wiring (dry environment)

A shorter DC link can be used.

Third, the cable size specification design must follow the following principles:

1) Short-distance DC connection from battery to indoor equipment. The rated current of the cable is 1.25 times of the continuous current of the cable.

2) The connection between the inside of the square matrix and the square matrix, the rated current of the selected cable is 1.56 times of the maximum continuous current in the calculated cable.

3) The connection of the AC load, the rated current of the selected cable is 1.25 times of the maximum continuous current in the calculated cable.

4) The connection of the inverter, the rated current of the selected cable is 1.25 times of the maximum continuous current in the calculated cable.

5) Consider the effect of temperature on the performance of the cable.

6) Consider the voltage drop not to exceed 2%.

7) Appropriate cable diameter selection is based on two factors, current strength and circuit voltage loss. The calculation formula is:

Line loss = current × circuit bus length × cable voltage factor (available from the cable manufacturer).