Input impedance and Output Impedance Algorithm of isolated power system based on state space averaging equation

Traditional method of calculating input impedance and output impedance is constrained by system scale and its difficulty to calculate sensitivity and stability margin. Based on system state space averaging equation, this paper presents total system algorithm and partitioned algorithm to analyze system steady state stability, which is applicable to high dimension isolated power system and has high calculation efficiency. We use the phase margin and magnitude margin of Nyquist curve respectively divided by the ratio of input output impedance as system stability margin index. Total system algorithm based on system impedance can be used to calculate stability margin stability sensitivity and estimate parameters of critical stability. The proposed algorithm has been validated by simulation test.