The cable failure caused by mechanical damage accounts for a large proportion of cable accidents. Some mechanical damage is very slight, did not cause a failure, to a few months or even years after the injury was developed into a fault.
2. Insulation damp
Insulation damp will cause the cable to withstand pressure drop and failure.
3. Insulation aging deterioration
Insulation aging can cause cable breakdown voltage and failure.
4. Overvoltage
Overvoltage will cause a defective cable insulation to generate electrical breakdown, causing cable failure. The main reasons are: atmospheric over-voltage (such as lightning); internal over-voltage (such as operating over-voltage).
5. Poor design and production process
Cable head and the middle of the design and production process is bad, can cause cable failure. The main reason is: the electric field distribution design is not careful; improper selection of materials; poor technology, not according to the requirements of the production process.