UHF Diagnostics and Monitoring for GIS

Abstract

The UHF technique of detecting partial discharges (PD) in gas insulated substations (GIS), which 10 years ago was seen as little more than an interesting laboratory investigation, is now recognised as an ideal means of giving an early warning of impending dielectric failures in a substation. its rapid acceptance by both utilities and switchgear manufacturers worldwide has resulted in part because the technique is simple in concept and easy to install; is remarkably free from interference and does not require any screening; is suitable for use at the highest system and test voltages; gives unambiguous results which are interpreted fairly readily; and is ideally suited to on-line measurements.