A Model-trajectory-based Method for Analyzing the Time-varying Oscillation Characteristics of a Fault System

Due to the impossibility for the equilibrium-point eigenvalue method to reflect the oscillation characteristic of the fault system correctly, and the difficulty in choosing the window length using a trajectory eigenvalue method, a model-trajectory method is proposed to analyze the eigenvalue of a fault system. First, the system is equated by the mutual factor after fault clearance. Then the branch current and power of the post-fault system is calculated by the branch current of the original and the fault component network, respectively. Furthermore, the equivalent model of the system is built and linearized at each measuring point. By combining the linearized model with the actual disturbed trajectory, the time series of the eigenvalue of the fault system is calculated. Simulation results of 2-generator system and a 16-generator system illustrate that the model-trajectory method is able to describe the time-varying oscillation characteristic of a fault system effectively and accurately.