A Single-Phase Line Break Fault Detection Method Based on Phase Voltage Difference Across Disconnection Points

Single-phase line break faults are among the common faults in distribution networks, often leading to hazards such as fires and electric shocks. To address the problem of line break fault detection, a mathematical model of single-phase line break is established for systems with neutral grounding through a small resistor. The mathematical expressions for the neutral point voltage of the power source and the phase voltages across the disconnection point are derived. A detailed analysis is performed on the changes in amplitude, phase, and sequence of the three-phase voltages on both sides of the disconnection point before and after the fault. It is observed that the fault phase voltage significantly differs before and after the occurrence of the fault. Based on these characteristics, a line break fault detection method utilizing the phase voltage differences across disconnection points is proposed and validated through digital simulations. The simulation results confirm the correctness of the identified characteristics of the line break fault and demonstrate that the proposed detection method effectively detects single-phase line breaks.