Study on the new method of partial discharge locating in transformer
The quick and precise locating of partial discharge is important in eliminating the hidden faults promptly and ensuring the safety and stability of the power system. In this paper, the existing methods of PD (Partial Discharge) locating were analyzed at first, and then a PD locating method based on ultra high frequency (UHF) and ultrasonic array signals in transformer was introduced, which regards the time point of signal detected by the UHF sensor as the time benchmark to calculate the distance between PD source and ultrasonic sensor and orientate the PD source based on the modified Fast Direction of Arrival(FastDOA) algorithm by ultrasonic array signals. This algorithm expands a real sensor array into several virtual arrays of different aperture to enhance the resolution, and averages the spatial spectrum of the virtual arrays to restrain the spurious peaks. Then the orientating based on the modified FastDOA algorithm was simulated with MATLAB. The sensors were developed and the PD locating experimental platform in transformer was built at last, the experiment results of which verify the effectiveness of the proposed method.