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This article mainly introduces the impedance based single-phase grounding fault location method for distribution networks, including its theoretical basis, algorithm steps, and simulation verification. First, starting from the impedance analysis of the transmission line model, the method of accurately measuring the location of the fault point through phase domain analysis is explained. Next, the process of impedance analysis for single-phase grounding faults was described in detail, that is, how to solve the impedance of the grounding fault points by calculating the voltage and current signals. Then, the specific process of the impedance based grounding fault location algorithm was introduced, including the calculation of equivalent load impedance, the calculation of starting voltage and current, the calculation of grounding current, and the solution of fault point location. Finally, simulation verification was conducted using an IEEE 34 node distribution system example in a MATLAB/Simulink environment, and the results showed that the algorithm has high positioning accuracy, with a maximum error of within 3%. [ABSTRACT FROM AUTHOR]

When a single-phase ground fault occurs, the transient zero sequence current will significantly increase. So, it is possible to detect whether a single-phase grounding fault has occurred in the transmission line by calculating and comparing the amplitude of transient zero sequence current. Only when the amplitude of the zero sequence voltage under the steady-state power frequency is greater than the preset threshold can the line selection device be effectively and reliably started. The instantaneous value protection device can also be used to start first, and then, the steady-state amplitude of the power frequency can be compared as the verification object. [ABSTRACT FROM AUTHOR]