High-voltage onsite commissioning tests for gas-insulated substations using UHF partial discharge detection

This paper describes the practical application of the ultra-high-frequency (UHF) partial discharge (PD) detection method which VA TECH Reyrolle has routinely applied to high-voltage onsite commissioning tests on gas-insulated substations (GISs) for more than 10 yr. The location of the PD sensors has a significant effect on the sensitivity of the UHF method, and research has been undertaken to quantify the parameters which affect this (i.e., attenuation, GIS geometry, etc.). Verifying the correct operation of the detection system and its sensitivity is a crucial step to prepare for a high-voltage (HV) test. In order to do this, special test equipment has been developed to ensure that all of the cabling, connections, etc., attached to the detection equipment are correct and that the detection level of the couplers is confirmed. Finally, the paper discusses IEC 60517 (general guidelines for GIS HV testing), its most usual interpretation, and how the application of the UHF technique can transform this interpretation.