Development and application of a portable multipurpose on-site/on-line PD measuring system

Until recently periodic partial discharge measurements were done on a 150 kV SF/sub 6/ gas insulated substation near Velsen in The Netherlands. These measurements have been performed conform the recommendations of the IEC 270. However, due to the load of the installation, it is almost impossible to take the GIS out of service to perform periodic measurements. Considering the position of the installation in the 150 kV grid no risks can be taken regarding the reliability of the installation for the rest of the technical lifetime. Moreover, failures in GIS can be preceded by partial discharge activity and therefore early detection can be helpful in determining the risk for failures. Therefore, a portable UHF measuring system has been developed for on-site/on-line testing of the GIS. Moreover, during the development of the portable PD measuring system, it has also been tested at oil- and air insulated systems. In this paper the used measuring system is described. The sensitivity of the measuring set-up has been checked as recommended by the CIGRE WG 15/33.03. Several examples from measurements obtained in the field show the different possible applications of the system.