Research on Propagation Attenuation Compensation Algorithm of PD Signal in Distribution Cable Lines

Partial discharge(PD) detection technology has become an important tool for condition detection of distribution cable lines. However, the PD signal propagation characteristics are not considered for the attenuation effect of the detected amount of apparent PD in use. The condition evaluation is taken simply based on a single criterion, which is easy to cause defects missed when the line is long or line internal wave impedance distortion. In this paper, the propagation attenuation characteristics and wave process characteristics of different typical partial discharge signals in 10kV cable lines with different specifications and sizes are studied by using ATP software and Blackburn cable model. The results show that the attenuation coefficient of 10kV cable line increases sharply with the increase of signal frequency. Different PD signals have different pulse width and amplitude results in different sizes of cables, and the difference is obvious in short distance cable propagation. Finally, combined with the partial discharge test data, a attenuation compensation algorithm based on the calibration data is proposed to modify the simulation results. The compensation coefficient obtained by the modified least square method can control the error within 10%.