Localization Algorithm for the PD Source in Substation Based on L-Shaped Antenna Array Signal Processing

A novel algorithm based on L-shaped antenna array signal processing is proposed in this paper for the localization of partial-discharge (PD) sources in substations. The principle of estimation of signal parameter via rotational invariance techniques has been used for finding the direction of arrival (DOA) of signals. Third-order cumulants of signals are used in this algorithm, by which Gaussian white noises and periodic narrowband interference mixed in observed signals can be efficiently suppressed. Planar location of PD sources can be obtained by solving the intersecting point of two lines in DOAs. Therefore, solving nonlinear equations can be avoided. Besides, it is convenient to replace the observed signals with their envelopes in this algorithm. The proposed algorithm is used to process mixed signals with simulated ultra-high frequency (UHF) signals by electromagnetic-wave simulation software, Gaussian white noises of different signal-to-noise ratios, and fixed-frequency noises. The planar location of PD sources is obtained approximately. UHF signals collected in substations and their envelopes have proven to be suitable to locate PD sources effectively by the proposed algorithm as well. Therefore, the accuracy and feasibility of the proposed algorithm are proved.

I. Introduction

Partial discharges (PDs) are not only the sign and manifestation of insulation degradation, but also the reason for insulation's further degradation. So the detection and localization of PDs is one of the main methods of the diagnostics of high-voltage (HV) insulation systems [1].