Two of the popular techniques are the murray and varley loop tests for locating faults in underground cables this article explains about few other popular techniques for locating faults in underground cables viz.
Underground cable fault detection method.
In this method you inject a specific frequency signal with help of a transmitter and then race it back with a receiver.
High voltage for pressure testing of the underground cables to find out faulty phase and the breakdown voltage with leakage current.
Before we discuss fault detection methods we shall study the various types of faults occurring in underground cables and their causes.
In order to identify the faults in the cable we need to develop special methods which will be discussed in this article.
There are many locating methods coupled with new detection technologies that make this task much easier and less time consuming.
The surges produced help in pinpointing the fault and tracing the route of the cable when used with acoustic fault locator.
Use of the arc reflection method combined with a high capacitance surge generator and state of the art pinpointing devices for underground cable fault locating will find faults in less time and with less risk of damaging good cable than classical techniques.
Finding the type of a fault in underground cables using a megger should not be a difficult task.
Underground cable fault distance locator circuit.
Finding the location of an underground cable fault doesn t have to be like finding a needle in a haystack.
1000 joules energy on 5 10 20 kv range.
But finding the exact location of the cable fault needs special techniques.
Cable detection or fault finding can be done via two methods.