A Method to Improve the Efficiency of Onsite Damped AC Test of Medium-Voltage Cables

In this letter, a simultaneous three-phase (STP) partial discharge (PD) test method for onsite damped AC test of medium-voltage cables is presented. By using the method, the onsite test efficiency improves nearly three times. A STP PD test module is implemented that is adapted to the commercial DAC test system. Onsite test was carried out on a 10 kV medium-voltage cable using the proposed test module to verify the feasibility. Benefitting from the symmetry of noises of the three phases, the test sensitivity is improved significantly. In the noise suppression experiment, the maximum background noise drops to 4.24 mV from 34.67 mV.