Faulty feeder detection based on transient attenuation and waveform similarity for low-resistance grounded system

In the case of a single-phase high-impedance fault (SPHIF) in a low-resistance grounded system (LRGS), the weak fault current makes it difficult to accurately detect the faulty feeder. To highlight the fault features, this paper first defines the concept of transient attenuation energy ratio and analyzes the fault features that can detect the faulty feeder. Under a specific phase condition, the transient attenuation energy ratio of the faulty feeder is much smaller than that of the healthy feeder. When the phase condition is not satisfied, the waveform similarity feature is analyzed to compensate for the lack of the transient attenuation energy ratio feature. Based on the two features, a comprehensive detection criterion for the faulty feeder is constructed. Moreover, to improve the efficiency and noise immunity of the feature parameter extraction process, this paper combines wavelet domain denoising and total least squares matrix pencil (WD-TLSMP). Based on this, a faulty feeder detection method that combines transient attenuation energy ratio and waveform similarity is proposed. The proposed method can accurately detect SPHIF under a variety of conditions as tested by simulation. Compared to other methods, it has a faster detection speed and is better adapted to intermittent SPHIFs.