Ground fault ride-through method and system for water turbine generator under extreme conditions

The invention provides a hydro-generator ground fault ride-through method and system under extreme conditions, and belongs to the technical field of hydro-generator operation and maintenance. The method comprises the following steps: acquiring a grounding current value of a neutral point of the hydraulic generator and a capacitance current value of a single camera end corresponding to a grounding fault point of the hydraulic generator; calculating the grounding current value of the fault point of the hydro-generator based on the capacitance current value of the single camera end corresponding to the grounding fault point of the hydro-generator and the grounding current value of the neutral point of the hydro-generator; and controlling the hydro-generator to execute corresponding fault ride-through operation according to a set strategy based on the grounding current value of the fault point of the hydro-generator. According to the embodiment of the invention, when the hydro-generator has the single-phase earth