Application of the CIGRE-sensitivity verification for UHF PD detection in three-phase GIS

This paper reports results with the new sensitivity verification for ultra high frequency (UHF) partial discharge (PD) detection applied to three-phase SF₆ gas-insulated substations (GIS) for rated voltages up to 170 kV. The procedure was developed by CIGRE WG 15/33.03.05. The aim is to examine the practical use of the proposed procedure and to investigate its extension to an unconventional sensor type. UHF PD measurements were carried out on a typical GIS section via potential grading electrodes. Derived results demonstrate the ability of these already built-in devices to serve as UHF sensors, to replace additional sensors sufficiently, and to make further design efforts unnecessary, if UHF diagnostics are required. Measurements, the experimental setup and the adequate test-vessel are described. The sensitivity of the new sensor is compared to the sensitivity of the IEC 60270 method and to other UHF sensors. Results concerning the detection of characteristic defects demonstrate the sensitivity of the new sensor arrangement