The terminal scratch defect is one of the typical defects of cable accessories. It is difficult to detect the weak discharge signal of the terminal small scratch defect under the withstand voltage test. In order to improve the sensitivity of partial discharge detection in the process of cable withstand voltage test, this paper proposes a method of using X-ray irradiation to excite the partial dis-charge of scratch defect in cable terminal, designs an experimental model of cable terminal scratch defect, and builds a partial discharge measurement system under X-ray excitation. The influence of X-ray on the partial dis-charge of terminal scratch defect is summarized, and the influence mecha-nism of X-ray on the discharge of scratch defect is analyzed. The experi-mental results show that X-ray can reduce the partial discharge inception voltage of cable terminal scratch defect. When the applied voltage is lower than PDIV and higher than XPDIV, X-ray can excite the discharge and the discharge stops with the stop of X-ray. When the applied voltage is higher than PDIV, X-ray irradiation can increase the discharge repetition rate and discharge amount of the self-sustained discharge sample. The research re-sults can provide a new method for improving the sensitivity of partial dis-charge detection under withstand voltage test.

Cable terminal, Partial discharge, Scratch defect, X-ray.