Partial Discharge Characteristics of Axial and Radial Knife Marks Defects in Power Cables

Abstract

The manufacturing process of the power cable terminal determines that the knife marks become a common defect in the terminal, especially in 10kV power cables. Some of these knife mark defects are radial and some are axial. In order to compare the damage of radial and axial knife mark defects on power cables, their partial discharge characteristics were measured and analysed. The electric field distribution of radial and axial knife trace defects was simulated. Axial and radial knife mark defects were prepared in real 10kV cable terminations. The high-frequency current method was used to measure the partial discharge characteristics of these defects, including the starting voltage of the partial discharge and the phase distribution spectrum of the partial discharge. The inception voltage of the partial discharge and the phase distribution spectrum of the partial discharge were obtained. The research results show that the damage of axial knife marks on cable insulation is greater.