Comparison of Sensitivity Between UHF Method and IEC 60270 for Onsite Calibration in Various GIS

It is more important to obtain the sensitivity line, which is defined as a correlation between the ultra-high-frequency (UHF) signal (mV) and apparent charge (pC), for onsite calibration regarding partial discharge (PD). Synchronous measurement of the UHF method and IEC 60270 enables us to obtain the sensitivity line and to estimate the apparent charge in on-site substations. The sensitivity line of 3-phase gas-insulated switchgear (GIS) is compared to that of single-phase GIS, and differences in defects are also discussed. The fundamental data in this paper contribute to on-site insulation diagnosis of GIS