Underground Power Cable Failure

Dividing the cable into successively smaller sections will enable you to narrow down the search for a fault.

Underground power cable failure.

Major causes are due to water ingress and poor workmanship. 1 risks reducing cable reliability because it depends on physically cutting and splicing the cable. Final results of a failure a cable failure almost always exhibits itself as either an open circuit or a short circuit. The paper insulation provided inside the cable is hygroscopic in nature.

Causes of faults in underground cables most of the faults occur when moisture enters the insulation. Excessive heating of the cable will cause degradation of the insulation and sheathing material and premature failure. 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. A substantial percentage occurs at splices terminations and joints.

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. Heat shrink covers can be used to waterproof these junctions and improve reliability. Sectionalizing this procedure as shown in fig.

Open circuits are more common in low voltage cables than at medium or high voltage. 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. There are two basic methods of locating an underground cable fault.