The introduction of cables with extruded dielectric insulation and of modern splicing technology hasimposed new conditions and restrictions on cable fault locating. The use of excessive high voltages andenergies during AC, DC and surge testing of service-aged power cable systems with extruded dielectricinsulation may overstress insulation, creating defects which become faults after the cables are returned toservice.This guide is intended to be applied to medium voltage distribution cables. Medium voltage distributionsystems generally operate at system voltages above 1kV and up to 34.5 kV nominal.The end user of the cable circuit should evaluate the necessity for verifying the integrity of extrudeddielectric insulated cables, and, if they are in critical service, proceed to perform the high voltage/energiestesting. If not detected during dielectric tests, defects in dielectric materials may result in cable failuresduring the transient voltage surge episodes while in service.
Purpose
This guide is intended to provide troubleshooting and testing personnel with information to quickly identify a faulted cable section or locate a cable fault with minimum risk of further damaging serviceable cables, terminations, and equipment.
