Location method of single line-to-ground faults in low-resistance grounded distribution networks based on ratio of zero-sequence admittance

Abstract

The conventional zero-sequence overcurrent protection method exhibits disadvantages for single line-to-ground faults in low-resistance grounded distribution networks, such as a long operating time, poor ability to resist fault resistance, and poor adaptability to network structure changes. This paper proposes a single line-to-ground fault location method based on the ratio of the double-end zero-sequence admittance. First, the characteristics of upstream and downstream zero-sequence admittance for single line-to-ground faults in different network structures were analyzed. Then, based on the upstream and downstream zero-sequence admittance information exchange, the ratio of double-end zero-sequence admittance is defined, which has significant differences between faulty sections and healthy sections. Subsequently, the operating criterion, setting value, and protection scheme were proposed. This method increases the ability to detect single line-to-ground faults using zero-sequence admittance, reduces the influence of network structure changes by calculating the ratio, improves the ability of fault location by using double-end information, and requires less data synchronization. Finally, PSCAD-based simulations under different conditions were performed on a 10 kV low-resistance grounded distribution network model. Both simulation and field test results verified the feasibility and effectiveness of the proposed method.