The paper insulation provided inside the cable is hygroscopic in nature.
Underground power cable failure.
There are two basic methods of locating an underground cable fault.
1 risks reducing cable reliability because it depends on physically cutting and splicing the cable.
Major causes are due to water ingress and poor workmanship.
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 lead sheath is.
Open circuits are usually the result of failed connectors or broken and or corroded conductors.
Sectionalizing this procedure as shown in fig.
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.
Dividing the cable into successively smaller sections will enable you to narrow down the search for a fault.
Excessive heating of the cable will cause degradation of the insulation and sheathing material and premature failure.
Heat shrink covers can be used to waterproof these junctions and improve reliability.
However the detection and localization of cable fault is challenging due to the limited access to the cable burned under the ground.
Causes of faults in underground cables most of the faults occur when moisture enters the insulation.
A substantial percentage occurs at splices terminations and joints.
Not all underground cable system failures are due to cable insulation.