A New Method for AC Voltage Withstand Test of High-Voltage Power Cable Based on Gas-Insulated Line and Distribution Partial Discharge Measurement

The AC withstand voltage test is an effective method to identify the main insulation performance and insulation defects of high-voltage cable. In the paper, gas-insulated line is designed and fabricated to connect the series resonance system with the cable under test. It is filled with SF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf> gas with a pressure of 0.35MPa and is suitable for test in limited spaces such as indoor substation. The distributed partial discharge (PD) detection system is developed, which consists of high frequency current transformer, synchronous sensor, detection unit, and communication unit, elastic cloud server, and analysis software. By applying distributed networking, PD detection of terminal and joint along the whole cable length during the AC voltage withstand test can be accomplished simultaneously with high efficiency. In addition, the equivalent time and the equivalent frequency map is proposed for separating different type of detected signals, by which sensitivity and accuracy of PD detection can be improved.