Distribution network asymmetric fault location method based on ratio of positive and negative voltage from secondary side of distribution transformer

This paper presents a new method for asymmetric fault location in distribution network with distributed generations based on the voltage at secondary side of distribution transformers. The ratio of positive and negative voltage is defined as the fault feature to achieve the estimation of fault section and the fault distance. Firstly, the relationship between positive sequence voltage and negative sequence voltage in the fault condition was analyzed with the variation of line distance. Secondly, fault section identification depends on the changes in the defined feature ratio upstream and downstream of the fault point. Thirdly, the fault distance calculation is performed by solving systems of determined equations. Finally, the proposed fault location method is validated on the modified IEEE 34-bus and IEEE 134-bus distribution network with or without distributed generations. Simulation results show the robustness and accuracy of the method under several scenarios with fault resistance, fault types, neutral grounding modes and measurement errors.