Fault processing method, device and system

The invention discloses a fault processing method, device and system. The method comprises the steps of detecting whether a voltage transformer in the distribution network has a ferroresonance fault or not; controlling a single-phase grounding switch to open and close in the case that the voltage transformer is detected to have a ferroresonance fault; detecting whether the distribution network hasa grounding fault or not, wherein the grounding fault includes at least one of the following: a single-phase arc grounding fault or a single-phase permanent grounding fault; controlling the phase grounding switch, which corresponds to the faulty-phase voltage transformer, in a three-phase grounding switch to close in the case that the distribution network is detected to have the above grounding fault, wherein the phase voltage transformer with the lowest grounding voltage value in the three-phase voltage transformer is the faulty-phase voltage transformer. The method solves a technical problem that the single-phase a