Partial Discharge Induction with X-rays to Detect Metal Particle Defects in SIR/XLPE Interface

Metal particle defect in SIR / XLPE interface is one of the common defects in cable accessories. In the early stage of defect formation, the discharge signal may be weak, and the traditional partial discharge detection method is poor at low voltage. In this paper, X-ray is used to excite the partial discharge of suspended metal particle defects, and the sensitivity of partial discharge detection is improved at low voltage. Firstly, the SIR/XLPE interface metal particle defect samples were made, and the partial discharge detection and X-ray excitation platform were built to carry out experimental research. The experimental results show that X-ray can reduce the partial discharge inception voltage (PDIV) of metal particles with different thickness. The smaller the thickness, the more obvious the reduction. When the applied voltage is higher than the PDIV under X-ray and lower than the PDIV under natural state, X-ray has a decisive effect on discharge. When the applied voltage is higher than the natural PDIV, the discharge becomes self-sustaining. X-ray can increase the discharge repetition rate and the number of discharges in the state.