UHF pd-diagnosis at high voltage cable terminations — International case studies

High voltage termintions are essential components in high voltage cable systems. A high reliability is given by high manufacturing quality and claimed company final testing. However onsite installation represent a considerable uncertainty for successful service of the system. Commissioning testing of cable systems according to IEC60840 and IEC62067 should allow a save, undistributed service. The cable can be put into service after passing successfully a commissioning test, which is increasingly accompanied by partial discharge measurement. While a cable is in service periodically performed offline testing and diagnostic measurements rarely take place due to the fact of high efforts for switching off the cable system. Online diagnostic methods, which could be used while a cable is in service, are valuable sources for information and represent a reasonable compromise between costs and benefit. UHF PD Diagnosis has proven to be a valuable and effective method for doing so at high voltage assets (cables, GIS, transformer), because this online measurement is performed at frequencies which are not affected by environmental noise.