Company: Henan Lubao Special Cable Co., Ltd.
Contact: Manager Su
Address: No. 13 Workshop B, Tiantan Venture Park, Huling Industrial Gathering District, Jiyuan City, Henan Province
Causes of heating of power cables , and 11 problems to pay attention to when selecting cables
When the power cable passes a certain load current, the maximum continuous working temperature allowed by the cable is always higher or higher (the maximum allowable temperature of the XLPE insulated cable is 90 ° C), and the cable will be heated for a long time. After continuous power-on operation, insulation thermal breakdown will occur, which will cause phase-to-phase short-circuit tripping of the cable, which may cause serious fire. The heating of the cable during operation may be caused by the following reasons:
1. The DC resistance of the cable conductor does not meet the requirements, causing the cable to generate heat during operation.
2. The improper selection of the cable causes the conductor cross-section of the cable used to be too small, resulting in overload during operation. After long-term use, the cable's heat generation and heat imbalance cause heat generation.
3. The cables are arranged too densely during installation, the ventilation and heat dissipation effect is not good, or the cables are too close to other heat sources, which affects the normal heat dissipation of the cables and may cause the cables to generate heat during operation.
4. The connector manufacturing technology is not good, and the crimp connection is not tight, which causes the contact resistance at the connector to be too large, and the wire and cable manufacturers will also cause the cable to generate heat.
5. Insulation performance of cables between phases is not good, resulting in low insulation resistance and heat generation during operation.
6. The local sheath of the armored cable is damaged, which will slowly damage the insulation performance after entering the water, causing the insulation resistance to gradually decrease, and it will also cause heating during the operation of the cable.
In order to ensure the safe operation of the cable, the following factors should be considered when selecting the power cable when designing the cable:
1. The rated voltage of the cable must 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 maximum continuous current of the power supply load.
3. The core cross section must meet the stability requirements of the power supply system in the event of a short circuit.
4. Check whether the voltage drop meets the requirements according to the cable length.
5. The minimum short-circuit current at the end of the line should enable the protective device to operate reliably.
6. High breakdown strength.
7. Low dielectric loss.
8. Quite high insulation resistance.
9, excellent discharge resistance.
10. It has certain softness and mechanical strength.
11. Long-term stable insulation performance.