Low frequency oscillation suppression method based on saddle node bifurcation two-layer vector analysis

Low frequency oscillation occurs many times in modern power system, which seriously threatens the safe and stable operation of power grid. In this paper, based on the saddle node bifurcation theory of nonlinear power system, the left and right eigenvector components corresponding to zero eigenvalue of the Jacobian matrix at the bifurcation of the dominant mode are calculated, and the active and reactive bidirectional variables strongly related to the dominant mode are captured. For the active power variable, the maximum participation factor is determined as the active power damping compensation basis through the sensitivity analysis of the model coefficient kl-k6 of the synchronous machine to the damping torque coefficient. For the reactive power variables, the saddle node bifurcation points of the bus corresponding to the reactive power participation factors are calculated, and the damping characteristics of the system are improved by the reactive power optimization method. Finally, the two-layer vector analysis method proposed in this paper is applied to Northeast Power Grid for simulation analysis, and the correctness and robustness of the proposed method are verified effectively.