The invention provides a grounding system for a neutral point in a high-voltage transformer; the system comprises a series resonant device connected between the neutral point of the high-voltage transformer and a ground the series resonant device is in power frequency resonance state with zero series impedance when a power system runs normally, good power frequency grounding of the neutral point of the transformer, and a capacitive element in the system can be free of transformer biasing due to direct-current components in the system; when the system experiences a grounding fault, a nonlinear inductor is saturated, a resonant loop is detuned, the capacitor is capable of effectively limiting faulty short-circuit current so as to ensure normal running of the breaker; meanwhile, the nonlinear inductor may limit the rise rate of faulty current and avoid transient current causing impact damage to the capacitor.