Abstract: Stator ground fault is a common fault of generators, and existing protection schemes suffer from low fault feature extraction accuracy and insufficient reliability. This paper proposes an adaptive protection method for single-phase ground fault of stator winding based on Empirical Wavelet Transform (EWT) and third harmonic fault component. Firstly, the amplitude and phase variation laws of zero-sequence voltage at neutral point and generator terminal during faults are analyzed by virtue of the third harmonic equivalent circuit of generator. Secondly, the EWT algorithm is adopted to extract the fault feature components. Finally, the adaptive braking coefficient is calculated according to the spectral energy of third harmonic voltage at generator terminal and neutral point, and the adaptive protection criterion is constructed. Simulation results show that the proposed protection scheme has high reliability and strong robustness.