Detection of Ferroresonance in Isolated Neutral System Based on Atomic Decomposition Method

According to the characteristics of ferroresonance signal, Atomic Decomposition Method was introduced as the analysis method of power system ferroresonance to overcome deficiency of traditional methods. Atomic Decomposition Method has a strong ability to analyze non-stationary signals. The best matching atoms could accurately characterize the ferroresonance signal, and also quickly detect the ferroresonance frequency and other parameters. Aiming at the ferroresonance excited by the single-phase instantaneous ground fault and according to the analysis of post fault three-phase voltage and the zero-sequence voltage, the zero-sequence voltage was divided into three groups by time. Based on the relationship between signal frequency and attenuation coefficient, a ferroresonance detection method was proposed to detect the ferroresonance fault and the type of the system. This method could also distinguish the system fault from single-phase permanent earth fault and single-phase instantaneous ground fault. The simulation results showed that the proposed method can accurately detect the ferroresonance fault of the system which verified the effectiveness of the method.