The Research On Detection Of Arc Grounding Fault And Section Location In Distribution Network

In 2015,the National Development and Reform Commission made a clear statement on improving the coverage of distribution automation.The development and improvement of the distribution automation system provides a lot of information for the automatic fault location,isolation and power restoration of the non-faulty section of the distribution network.Therefore,in order to improve the reliability of power supply,a highly robust fault location method is required.However,when the arc grounding fault occurs in the distribution network,the instability of the grounding arc leads to difficulties in fault detection and location,which restricts the development of distribution automation technology.Next,this paper will focus on the two directions of arc grounding fault detection and fault section location.For the detection of arc grounding fault,this paper proposes a new method for arc grounding fault detection based on the mixed features of fault voltage in time domain,frequency domain and phase domain.Firstly,according to the model of arc grounding fault,the theoretical expression of the fault voltage generated by the arc grounding fault is derived in detail;Based on the derived expression,several features of the fault signal were extracted from three aspects of the fault voltage signal: time domain,frequency domain and phase domain,respectively.In order to verify the effectiveness of the extracted features in identifying arc grounding fault,three fault discharge models including arc grounding fault are built in this paper,and three different discharge experiments are obtained under 10 k V experimental condition.According to the feature extraction method proposed in this paper,the respective features are extracted from produced three discharge data;Finally,the trained neural network is used to identify arc grounding fault in different faults based on these extracted features,and the accuracy reaches 98.22%.Thus,the experimental results verify the feasibility and effectiveness of the feature extraction method in this paper.In terms of fault section location,this paper studies and improves the currently popular fault location matrix algorithm based on feeder terminal unit(FTU).The improved algorithm does not need to consider the positive and negative directions of the fault current in the process of generating the network topology matrix,and the generated matrix contains only 0 and 1 elements,which makes the matrix more sparse.Moreover,the fault determination matrix is obtained by directly updating the fault information on the basis of the network topology matrix,which avoids the traditional tedious matrix product operation.In order to verify the effect of the improved algorithm in localization,the location simulation verification of the non-arc grounding fault was carried out,and the arc grounding fault location simulation verification was carried out combined with the arc grounding fault identification method proposed in this paper.The results are consistent with the actual fault section.In summary,the research in this paper can not only realize the segment location of non-arc grounding fault according to the improved matrix algorithm,but also can perform segment location of arc grounding fault according to the identifying method of arc grounding fault proposed in this paper.Therefore,this paper provides a reference for the fault location method under distribution automation,and provides theoretical support for the isolation of faulty sections and the restoration of power supply in non-faulty sections.