New PD sensor techniques for highly pressurized dry air-insulated systems and an alternative method to CIGRE sensitivity verification procedure

With the development of gas insulated switchgear (GIS) utilizing dry air as an alternative insulating gas to SF6, monitoring technologies for partial discharges (PD) have contributed to the reliability of the GIS and have become increasingly important. However, research and reports concerning PD characteristics in dry air are limited. In particular, sufficient knowledge regarding PD diagnosis under high-pressure dry air conditions is required. In this study, PD characteristics in high-pressure dry air are investigated to validate the applicability of the current Ultra High Frequency (UHF) detection method and to confirm that PD characteristics comparable to SF6 are observed under high-pressure dry air. By utilizing the obtained PD characteristics in high-pressure dry air, optimization of…