The reason of power cable fault
1. Insulation aging metamorphism
Electric power cable insulation will suffer with effect of thermal, chemical and mechanical action, so that the insulating medium physical and chemical changes, and decreased the insulation of the medium level. Insulation be affected with damp be affected with damp. The middle connector or terminal head caused by structure and seal or the installation quality is bad insulation be affected with damp be affected with damp; Lead manufacturing cable package leaving sand holes or cracks and other defects, also can make the cable to be affected with damp be affected with damp.
2. Cable overheat
There are many causes of the cable overheating. Internal cause is the cable insulation inside the air gap caused by free local heat, so that insulation carbonization. External cause is installed on the cable populated areas, cable tunnel and cable, wear in the drying tube and with access to cable, cable due to cable overload or bad heat dissipation, and make the insulation damage of acceleration.
3. Mechanical damage
Mainly refers to the external force of cable damage. This is mainly due to the vehicle vibration and other mechanical action, make the cable shape. Cable deformation in bending excessive, damaged the internal insulation or cause insulation inside the air gap.
4. Sheath corrosion
Due to electrolysis corrosion or chemical action make the power cable lead package, because of the nature and degree of corrosion, lead covered with red, yellow, orange and pale yellow sponge compound or similar pores.
5. Overvoltage caused the breakdown
Atmosphere overvoltage and inner overvoltage of cable insulation breakdown caused by stress exceeds allowable values. And analyze the actual fault show that many outdoor terminal fault, is caused by atmospheric overvoltage.
6. Middle connector, terminal head of design and production process problems
Stripping semiconductor, damage to internal insulation or insulating surface particles, dust and other impurities; Cable head seal bad, make the internal insulation has moisture, cause insulation be affected with damp be affected with damp; Cable joint process is not standard, non-standard seal, cause ground; Production environment humidity is big, cause the production site (cable head) insulation integrity of be affected with damp be affected with damp; Cable grounding errors, causing the ground wire forming circulation or rupture.
