Lord Consulting

The authors present a paper detailing some recent on-line partial discharge (PD) testing and software data analysis work carried out to develop a suitable and robust method for on-line PD spot testing and monitoring of in-service, energised high voltage outdoor cable sealing ends. The work was carried out in follow-up to several failures of 132kV and 220kV HV cable sealing ends at electricity transmission utilities in Europe. One of the main challenges encountered when testing HV cable sealing ends is to differentiate between the highly dangerous internal PD activity within the sealing ends from the large number of external, high frequency impulsive interferences originating from other nearby items of plant. Sources of such interference include corona and discharges on the surfaces of ceramic insulators related to atmospheric pollution and weather. New techniques have been developed that involve synchronously capturing data from four sensors and comparing the signals in order to identify internal PD activity in the sealing end. The system can be used as a tool for commissioning new cable sealing ends and also assessing the insulation condition of aged ones.

IPEC_B1-205 Renforth et al-On-line Partial Discharge Spot-testing and Monitoringof HV Cable Sealing Ends (457kb PDF)