Views: 0 Author: Site Editor Publish Time: 2021-12-13 Origin: Site
What are the reasons for the heating of power cables during operation? The following are the six main reasons why power cables generate heat during operation.
1. The cable conductor resistance does not meet the requirements, causing the cable to generate heat during operation. 2. Inappropriate cable selection, resulting in too small conductor cross-section of the cable used, and overload during operation. After a long time of use, the heating and heat dissipation of the cable will be unbalanced, resulting in heating. 3. When the cables are installed too densely, 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 also cause the cables to generate heat during operation. Fourth, the joint manufacturing technology is not good, and the crimping is not tight, resulting in excessive contact resistance at the joint, and heating of the cable. 5. The insulation performance between phases of the cable is not good, resulting in low insulation resistance and heating during operation. 6. The partial sheath of the armored cable is damaged, which will cause slow damage to the insulation performance after the water enters, resulting in a gradual decrease in the insulation resistance, and also causing heating during the operation of the cable.
After the power cable generates heat, if the cause is not found and the fault is solved in time, the insulation thermal breakdown phenomenon will occur after the cable continues to be energized. It may cause a phase-to-phase short circuit and tripping of the cable, which may cause a serious fire.
The following eleven factors should be considered when choosing a power cable:
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 maximum continuous current of the power supply load; 3. The cross-section of the core must meet the stability of the power supply system when the power supply system is short-circuited. Requirements; 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 protection device to operate reliably. 6. High breakdown strength; 7. Low dielectric loss; 8. Very high insulation resistance; 9. Excellent discharge resistance; 10. With certain flexibility and mechanical strength; 11. Long-term stable insulation performance.