Developments in cable diagnostics

A number of power cable diagnostic techniques are discussed. The quality and detail of the information generated by these techniques varies widely, as does the complexity of measurements and equipment required. Study of cable history and examination of failures and cable samples provides a useful insight into the network with little additional work. DC test methods offer the greatest ease of use due to the small physical size, however, their diagnostic capabilities are limited. AC testing provides a greater level of diagnostic flexibility but brings with it increased size and expense. However, the ability to carry out diagnostic testing, particularly partial discharge mapping, does also attract financial benefits such as optimising replacement and reducing service failures. Most of the techniques discussed have been available for some time. The main development in this area has not been in introducing new techniques but in the better use and application of techniques which have existed for some time. Careful choice of these techniques together with informed diagnosis based on the results can provide a cost effective and valuable asset management tool.