A Method for Identifying and Locating Open-Neutral Faults in Low-Voltage Distribution Networks Based on Third Harmonic Energy Variation

Detecting open-neutral faults in low-voltage distribution systems is important for e maintaining system reliability and safeguarding electrical equipment from possible risks such as over-voltage and under-voltage. This paper presents a novel fault detection and localization method based on variations in third harmonic energy. In a three-phase, four-wire system where no disconnections occur, the neutral wire serves to conduct third harmonic currents generated by nonlinear loads to the ground. However, when the neutral wire is broken, these harmonic currents are redirected to alternative loads, leading to observable shifts in third harmonic energy levels. By analyzing the changes in energy both before and after the fault, and distinguishing them from normal load fluctuations, the proposed technique can accurately detect and locate open-neutral faults. Simulation results confirm that this method provides precise fault detection across different loading scenarios, even when the load distribution is balanced.