A DECAYING DC-OFFSET FILTERING SCHEME BASED ON THE STATIONARY WAVELET TRANSFORM

摘要

This paper presents a novel scheme for removing a decaying DC-offset from fault current measurements in a faulted power transmission lines. The technique is based on Stationary Wavelet Transform(SWT). The performance of the scheme on two study cases is investigated; the statistical performance in relation to noise on a hypothetical signal, and a modeled segment of a utility network in South Africa. The result shows that the scheme is robust, and that it can remove any dc-offset even at a noise level of 20 dB. The output of the scheme can be used for fault detection, classification and location.