Study of Improved RSS Algorithm for Ultrasonic Array Applied to PD Location in Transformer

An improved rotated sub-space (RSS) algorithm is proposed for the application of array technology in partial discharge (PD) location in transformer. The algorithm is based on classic RSS algorithm and high-order cumulants, and it is studied through numerical simulation and experimental tests. Based on an L-shaped and a cross-shaped array, the simulation of single and multiple PD source direction is carried out to compare the classic RSS algorithm with improved RSS algorithm. The results confirm the processing capacity in wideband focus, aperture expansion, enhance of directing, and noise suppression of improved RSS algorithm. Moreover, both algorithms are used for PD location experiments, showing that the error of improved RSS algorithm is ~3°. Improved RSS algorithm solves the problem of wideband focusing in PD location, enhances the performance of the array aperture and directing, achieves the effect of the array consists of much more elements with a virtual expansion, simplifying the follow-up circuit.