ESTIMATION OF PARTIAL DISCHARGE PARAMETERS IN GIS USING ACOUSTIC EMISSION TECHNIQUES

Conventional electrical techniques for the monitoring of partial discharge (p.d.) activity in enclosed systems like gas insulated substations (GIS) have certain inherent limitations, which has prompted the exploration of non-electrical techniques. Acoustic detection of p.d. in a GIS is based on the retrieval and analysis of mechanical signals produced on the walls of the metallic enclosure due to electrical discharge activity within. A theoretical modelling of the process by which a discharge produced within the GIS sets up detectable signals on the walls of the enclosure seems to be lacking. The present work consists of the development of a model for the propagation of electrically induced acoustic waves through gaseous medium, and their effect on the walls of the GIS, giving adequate representation to fluid–structure coupling. A numerical simulation of the process is shown to yield important information about the proper type of instrumentation required for such non-invasive tests, and aid in designing robust strategies for locating the source of the discharge.