Underground Power Cable Failure

Heat shrink covers can be used to waterproof these junctions and improve reliability.

Underground power cable failure.

Open circuits are usually the result of failed connectors or broken and or corroded conductors. Dividing the cable into successively smaller sections will enable you to narrow down the search for a fault. Not all underground cable system failures are due to cable insulation. Excessive heating of the cable will cause degradation of the insulation and sheathing material and premature failure.

The paper insulation provided inside the cable is hygroscopic in nature. The heat may come from an external source or may be generated by the resistance to current flow in the conductor a particular problem if the cable is overloaded and or underrated for the application. The use of underground cables is essential in power distribution networks as they mitigate the issues related to space availability and minimise line breakdown and increase system reliability. However the detection and localization of cable fault is challenging due to the limited access to the cable burned under the ground.

Other causes include mechanical injury during transportation laying process or due to various stresses encountered by the cable during its working life. There are two basic methods of locating an underground cable fault. Final results of a failure a cable failure almost always exhibits itself as either an open circuit or a short circuit. Major causes are due to water ingress and poor workmanship.

Causes of faults in underground cables most of the faults occur when moisture enters the insulation. Sectionalizing this procedure as shown in fig. A substantial percentage occurs at splices terminations and joints.