Characterisation of discharge phenomena in voids

As part of a large program to characterize partial discharge activity by a variety of techniques, the results of a preliminary investigation of corona discharge activity are reported with emphasis on electromagnetic emissions. Specifically, electrical, electromagnetic, acoustic, and optical measurements of void and surface discharge were performed and correlations among the resultant measurements from different techniques and the prevalent (controlled) discharge phenomena were sought. It is believed that this approach should provide a clearer understanding of the relationship between measurements of discharge activity and the partial discharge process. This, in turn, should make possible a better assessment of insulation integrity. The results presented are largely concentrated on electromagnetic responses