Analysis Of Line Selection And Location Of Single-phase Ground Fault In Distribution Network Based On Resistive Current

Among all the faults occurred in distribution network,the fault type with the highest probability is single-phase grounding fault.Therefore,it is of great significance to study the line selection and location of single-phase ground fault.In this paper,the existing single-phase grounding fault line selection technology through neutral point input resistance is introduced,and its principle and criterion are analyzed theoretically.It is found that there are some defects such as insufficient resistance to high resistance when using zero sequence current to select line.In order to solve this problem,this paper proposes an analysis method of single-phase grounding fault line selection and location based on resistive current.A new criterion of line selection and location based on resistive current is proposed,and its high resistance capability is verified.The principle of resistive current line selection and location is studied.By comparing the theoretical value of resistive current of sound line and fault line before and after the middle resistance is put into operation,it is concluded that the line with the maximum resistance current flowing through is judged as the fault line,and the fault section is determined between two adjacent observation points with different resistive current ratio variation characteristics,and it is verified that even when the transition resistance is as high as 5k?,the resistive current can also realize line selection and positioning.A 10 kV distribution network model is built in PSCAD/EMTDC to verify the change of resistive current parameters of ungrounded neutral system and resonant grounding system before and after the middle resistance is put into operation,and the change of zero sequence current before and after fault and medium resistance is compared to verify the reliability of resistance current line selection criterion under different transition resistance and capacitance current,and the ability of high resistance line selection is tested.At the same time,the difference of resistive current in fault section and sound section is compared,and fault section location is realized by resistive current.Finally,programming in MATLAB,the reliability of line selection and location criteria under different neutral grounding modes and fault conditions is analyzed.Combined with the experimental data,the accuracy of resistive current in fault line selection and fault section location is verified.