On-site PD diagnosis of transmission power cables

Condition assessment of HV assets is one of the issues of asset management in power utility business. In particular, due to there importance in the transmission network is the knowledge about the starting conditions during after-laying as well as the actual condition of HV power cable sections during operation after several years of service very important. With regard to partial discharge (PD) processes in transmission power cables there is a need for advanced, sensitive and economical attractive tools suitable for non-destructive PD diagnosis on-site: the after-laying testing as well as the service diagnosis. In an international co-operation, based on utility experiences and laboratory investigations as obtained for PD diagnosis of distribution power cables using damped AC voltages, a complete new method of PD detection and localization for transmission power cables up to 250kV has been developed in 2003 and in field use for already three years. In this contribution based on field experiences on power cable system up to 220kV the test procedure and the data interpretation are discussed.