多次操作冲击对含刀痕缺陷10 kV电缆终端局部放电特性的影响

In order to study on the aging of 10 kV cable termination with artificial defects under switching impulses in the distribution system, knife incision defects based on the practical situation were made by using the cable segment in running. After the maximum switching impulse that might occur in the network was taken into account, switching impulses of 250/2 500 μs with 40 kV in magnitude were applied to experimental samples. The PDIV and PDEV of the aged cable termination were detected and the PRPD spectrograms at 15 kV/50 Hz were measured to monitor the termination's condition in the course of aging. Test results illustrate that the PDIV and PDEV are prone to increase and subsequently decrease as the number of applied impulses increases. The discharge form of the sample at the initial stage of aging is between the surface discharge and internal discharge. In the middle stage, the discharge is mainly based on internal discharge. The discharge gradually transforms into unipolar discharge in the final stage. The trends of maximum discharge and average discharge during the aging are in a 'bathtub' shape. From the perspective of the development of defects, it is believed that discharges at the initial and middle stages of aging are mainly affected by burrs of a kerf, and the development of the discharge at the final stage of aging is mainly relevant to internal defects of XLPE materials.