METHOD AND DEVICE FOR DETECTING DIRECTIONAL GROUNDING FAULT BASED ON THREE PHASE CURRENT VARIATION

摘要

A method for determining a fault phase during a single phase grounding fault and determining whether the fault is a downstream fault or a upstream fault The present invention provides A directional grounding fault detecting method, comprising: a. detecting a grounding fault based on sampled three phase currents IA, 1B and ic, and obtaining a time point t corresponding to an moment at which the grounding fault is just detected; b. determining whether it is a single phase grounding fault or a two phase grounding fault based on three incremental phase currents Ai*, Aie and Aic at moment t; and c. when it is determined as a single phase grounding fault, it is determined whether the fault is an upstream fault or a downstream fault based on an amplitude of the incremental phase current of the faulted phase.