Reactive Current Disturbance Islanding Detection Method with Frequency Positive Feedback

A desired islanding detection method is required to detect islanding situation within an acceptable duration and to reduce the impact on power quality.In this paper,the principal of traditional reactive current disturbance method is discussed.Then,a novel method based on reactive current disturbance is proposed.The proposed method applies a periodic reactive disturbing current and feeds forward the frequency.When the frequency changes,it further applies a positive feedback reactive disturbing current to bring the frequency out of limit.This method can detect islanding quickly without Non-Detection Zone(NDZ).It doesn′t affect the frequency of grid or inject harmonic to grid and has minor impact of power factor.Simulation results verify the validity of the proposed method.