Research on DC Breakdown Characteristics for the Insulation of 10 kV AC XLPE Cables

It is of great significance to study the direct current (DC) breakdown characteristics of the alternating current (AC) cross-linked polyethylene (XLPE) for converting AC XLPE cables into DC operation. The AC and DC breakdown experiments were carried out on 10 kV AC XLPE samples under three different dwell times (1 min, 5 min and 15 min). The characteristics between the breakdown electric field and the breakdown time under AC and DC voltage was obtained according to the date of breakdown experiments. The results show that the 1 h AC and DC breakdown electric field is 69.80 MV/m and 170.96 MV/m respectively, and the DC breakdown electric field is always higher than the AC breakdown electric field in the range of 1 h to 40 a.