The impeller system as one of the most critical components of wind turbines, its working environment is harsh, the failure rate is high, under the condition that the wind speed is unstable for a long time, the blade will have irregular vibration or even fracture. Considering the wind turbine impeller unbalanced faults, a signal noise reduction method based on the geometric similarity of probability distribution is proposed, and the electrical characteristics and fault characteristic frequency of generator stator current under impeller unbalanced fault are deduced. A method based on stator current Park vector mode square signal is used to deal with the stator current signal, the interference of the base wave current is eliminated, and the fault characteristic frequency is extracted, which provides a basis for the unbalanced fault diagnosis research of the subsequent impeller system.