Faulty Feeder Identification and Fault Area Localization in Resonant Grounding System Based on Wavelet Packet and Bayesian Classifier

Abstract

Accurate fault area localization is a challenging problem in resonant grounding systems (RGSs). Accordingly, this paper proposes a novel two-stage localization method for single-phase earth faults in RGSs. Firstly, a faulty feeder identification algorithm based on a Bayesian classifier is proposed. Three characteristic parameters of the RGS (the energy ratio, impedance factor, and energy spectrum entropy) are calculated based on the zero-sequence current (ZSC) of each feeder using wavelet packet transformations. Then, the values of three parameters are sent to a pre-trained Bayesian classifier to recognize the exact fault mode. With this result, the faulty feeder can be finally identified. To find the exact fault area on the faulty feeder, a localization method based on the similarity comparison of dominant frequency-band waveforms is proposed in an RGS equipped with feeder terminal units (FTUs). The FTUs can provide the information on the ZSC at their locations. Through wavelet-packet transformation, ZSC dominant frequency-band waveforms can be obtained at all FTU points. Similarities of the waveforms of characteristics at all FTU points are calculated and compared. The neighboring FTU points with the maximum diversity are the faulty sections finally determined. The proposed method exhibits higher accuracy in both faulty feeder identification and fault area localization compared to the previous methods. Finally, the effectiveness of the proposed method is validated by comparing simulation and experimental results.

Calculating Feeder Fault Current with MATLAB Software Program

“…From reference [1] Interpretation theorem and application for the basic textbook of academic theory, as for [2][3][4][5][6][7][8][9], they are based on theoretical integration and applied were published on journal within actual power systems. The content is from the power system -positive, negative, zero sequence and the relationship between the three -phase wiring of the first and second side coils of each transformer equipment and the neutral point grounding of the generator to the change of the system impedance value, next to connect the transmission line impedance to draw the "Thevenin equivalent" impedance value of the power system, then find the fault current value of each section in sequence.…”

Multiple Random Forests Based Intelligent Location of Single-phase Grounding Fault in Power Lines of DFIG-based Wind Farm

“…At present, there are a few studies on fault location for this type of network, resulting in a lack of effective diagnostic techniques and means of location. Fault location approaches can be mainly categorized into traveling wave approaches [2] - [7], fault analysis approaches [8] - [12], and artificial intelligence approaches [13]- [18]. Traveling wave approaches are simple, but there are multi-branch lines and hybrid lines in the distribution network and wind farm, which make it difficult to recognize the traveling wave head and determine the wave speed.…”

Influence of wavelet characteristics on single-phase grounding fault line selection

“…After a single-phase grounding fault occurs in the distribution network, the non-fault phase voltage will rise 3 times, endangering the system insulation, seriously developing into phase to phase short circuit, resulting in the expansion of the fault range. Therefore, it is of great practical significance to find out the fault line quickly and reliably [1]. China's distribution network mostly adopts neutral indirect grounding.…”