Effect of γ-ray irradiation on partial discharge characteristics in internal void

In insulation diagnosis, it is very important to detect voids in electrical insulation. In this paper, a trial to detect voids was made in terms of measurements of partial discharge characteristics and scanning of a narrow /spl gamma/-ray beam. The experiments were performed under the application of a very low frequency voltage. When we take advantage of the change of partial discharge characteristics caused by /spl gamma/-ray irradiation of a void, there is a high possibility to establish a new detection method of voids in insulators using conventional partial discharge measurements under low frequency voltage application and scanning of a narrow /spl gamma/-ray beam.