A consultant's overview of experience with condition monitoring systems worldwide

In the UK, research and development work on SF/sub 6/-gas as an insulating and interrupting medium started in earnest in the late sixties. In the early seventies, a joint venture by the two main transmission switchgear companies, GEC and Reyrolle, produced the first SF/sub 6/ GIS installation in England. It was commissioned on the CEGB network at Neepsend in 1976 and has given trouble-free service ever since. The author was part of the UK SF/sub 6/ switchgear development programme from its inception. The SF/sub 6/-era in the UK, led to a new generation of SF/sub 6/ GIS and AIS switchgear. For eight years, as a consultant, he has had the opportunity of gaining first-hand knowledge of other switchgear designs and service experience of installations worldwide. Drawing upon his experience this paper focuses on GIS equipment. It examines the design and performance of various GIS installations and reviews the case for condition monitoring or condition assessment, for planned preventive maintenance and for condition dependent maintenance. It also comments on cost implications.