Diagnostic Methods for GIS Insulating Systems Using External Antenna

Abstract

We have developed a partial discharge detection system using an external antenna that can be easily installed on the outside of the GIS. The antenna is fitted closely to the outer circumference of the insulation spacer and it can detect electromagnetic radiation of the partial discharge with high sen-sitivity.
To have high sensitivity even in noisy condition, three kinds of methods that can eliminate external noise effectively were verified. In addition, the locating method of defect based on distance atteuna-tion are confirmed. Acctually, the insulation monitoring system which employs the anntenna is used in a substation which had already been installed. At present, it is operating satisfactory.