Power cables are cables used for transmitting and distributing electrical energy. Power cables are commonly used in urban underground power grids, power station outgoing lines, internal power supply of industrial and mining enterprises, and underwater transmission lines crossing rivers and seas. The proportion of cables in power lines is gradually increasing. Cable products used for transmitting and distributing high-power electrical energy in the backbone lines of the power system, including power cables with various voltage levels and insulation, ranging from 1-500KV and above.

When passing through a certain load current, power cables will definitely generate heat. As the load current increases, the surface temperature of the cable will become higher. If not dealt with in a timely manner, the consequences can be imagined.

For example, polyvinyl chloride (PVC) cables are designed with a core temperature limit of 70 degrees Celsius, resulting in a surface temperature drop of 5-10 degrees Celsius. So it is basically safe for the surface temperature of the cable to be below 60 degrees. From the perspective of power maintenance, of course, the lower the temperature, the better when it is higher than the ambient temperature.

The selection of power cables should consider the following eleven factors:

1. The rated voltage of the cable should be greater than or equal to the rated voltage of the power supply system at the installation point;

2. The continuous allowable current of the cable should be equal to or greater than the larger continuous current of the power supply load;

3. The cross-sectional area of the wire core should meet the stability requirements of the power supply system during a short circuit;

4. Verify whether the voltage drop meets the requirements based on the length of the cable;

5. The small short-circuit current at the end of the line should enable the protection device to operate reliably.

6. High breakdown strength;

7. Low dielectric loss;

8. Relatively high insulation resistance;

9. Excellent discharge resistance performance;

10. Has a certain degree of flexibility and mechanical strength;

11. The insulation performance is stable for a long time.