Abstract
To evaluate the suitability of the DC withstand test for use as the after-laying test for extrahigh-voltage XLPE cable lines, especially 500-kV XLPE cable lines, we studied the effectiveness of the DC withstand test and the influence of DC voltage application on AC insulating performance, using XLPE cables with artificial defects. DC breakdown strength of the cable with defects does not decrease radically compared with AC breakdown strength due to space charge effects. The defects that are detected by the AC withstand test might not be detected by the DC withstand test and short-circuited trees may appear at earthing after the DC withstand test, degrading the AC insulating performance. The DC withstand test should therefore not be used as the after-laying test for 500-kV XLPE cable lines.
