An Improved Method for Cable Defect Positioning Based on Gaussian Window Pseudo Wigner-Ville Distribution

Time-frequency domain reflectometry is one of the promising methods for locating latent cable defects recently. Nevertheless, the traditional Wigner-Ville distribution, which is used to convert the signals into the time-frequency domain, can lead to cross-term interference problems for multi-component signals. To avoid the influence of the cross-terms on the positioning curve, the Gaussian window pseudo Wigner-Ville distribution is utilized to suppress the cross-terms. In the simulation model, the amplitude of the cross-terms is greatly reduced without changing the time-frequency center of the multi-component signal, which verifies the ability of the distribution. In experiments, a 160 m 10kV cable was used as the test object, and four accelerated thermal aging defects which were heated at 135 °C for different days were set at 63 m of the cable to simulate the latent defects. The results show that the peaks of the positioning curves at the defects based on the proposed method in this paper are much higher than that based on the traditional one. And the method is expected to be applied in the power systems in the future.