Partial discharge phenomena with X-ray irradiation

The partial discharge phenomena induced by X-ray irradiation were investigated in gas cavities, transformer oil, and oil/paper insulation systems. The characteristics of X-ray induced PD were described and the location of the PD site was determined. With conventional PD measurement techniques, statistical time lag in a cavity could make a dangerous defect undetectable. The application of X-rays can increase the free electron production rate in the cavity and decrease the statistical time lag, resulting in an improved PD sensitivity.