A Novel Single-Phase-to-Ground Fault Location Method Based on Phase Current Differences in Power Distribution Systems

Abstract

The small-current grounding method has the feature that the fault arc can be extinguished automatically and has been widely used. However, when a single-phase-to-ground (SPG) fault occurs, the fault characteristics are very weak, making fault location difficult to realize. When an SPG fault occurs, the fault phase current upstream of the fault shows a significant difference to the sound phase current, and there is also a striking difference between this fault phase current and the phase current of the remaining sound lines. A method for locating SPG faults in distribution networks based on phase current differences is presented. Firstly, the waveforms and energies of the phase current fault components (PCFCs) over a time span are analyzed. Secondly, a fault section location method based on the waveform and energy differences of PCFCs is proposed. This method can be used where the fault grounding resistance is high or where there are branch lines. Then, a fault section location scheme is proposed based on installed data collection terminals. The PCFC energy and waveform difference composite criteria are used in this scheme, enabling the selection of faulty phase, faulty feeder, and faulty section. Finally, the small-current grounding distribution network is modeled, and the feasibility is verified.