Application of partial discharge mapping technology in CLP power 11kV cable network

CLP Power Hong Kong Limited (CLP Power) is currently adopting a (N-1) security philosophy to provide a reliable, secure and good-quality electricity supply to our customers in Kowloon, the New Territories, Lantau and most outlying islands of the HKSAR. With a mission to continuously strive for our best in the supply reliability of distribution system, CLP Power has introduced Partial Discharge (PD) Mapping technology into its 11kV cable network since 1999. PD Mapping exhibits its diagnostic capability of dielectric integrity of cables in service, enforcing reliability-centered maintenance strategy through condition monitoring. Its application in the CLP Power 11kV distribution network includes condition monitoring of 11kV cables for interconnection, namely bar-to-bar interconnectors, bar-to-ring interconnectors and ring-to-ring interconnectors, and conjuncture tests on the tripped circuits with proven results of insulation diagnostic tests such as HV AC Pressure Test and 10kV Megger Insulation Test. This paper discusses CLP Power's experience on the application of PD mapping in our 11kV cable network and its limitations. Findings from successful stories and subtle analysis of difficult cases are highlighted to show the effectiveness of the technology.