Instrumentation for the Detection and Locatiion of Incipient Faults on Power Cables

A description is given of the instrumentation being developed for the detection and location of incipient faults in power cables by the processing of the electromagnetic noise that appears at the power cable terminals. After a discussion of the basic concept, which involves a correlation technique, the implementation of the concept in the form of a microprocessor controlled, polarity coincidence type of correlator is described. Test results of the instrument with various types of noise sources are given. These include tests on a length of 15 kV class underground distribution cable with staged incipient faults. Some of these tests show that the instrumentation is capable of detecting and locating partial discharge noise on the cable with interesting precision.