Power system small signal stability analysis based on character identification of time domain simulation

Selection of disturbance variables and observation response variables has great influence to small signal stability analysis of time domain simulation, whose oscillation mode set may be incomplete, making it is impossible to obtain physical insight of system stability and find out related measure to improve system stability level. To overcome these problems, correlation between characteristic matrix and perturbance dynamic response of state variables is set forth, where dynamic response of increment of state vector can be approximated by result of state transition matrix multiplying by its disturbance of state vector. Estimation method of one time perturbance and orthogonal perturbance are presented to calculate the state transition matrix, while characteristic matrix can be calculated by its Taylor series expansion. Estimation method of one time perturbance is difficult to achieve invertible perturbance matrix or has poor accuracy, while estimation method of orthogonal perturbance has advantage of high accuracy, high robustness and high speed. Theoretical analysis and simulation test show that eigen-structure analysis can be implemented based on proposed method by time domain simulation of power system, which can provide technical supporting to obtain physical insight for system stability analysis and controller design.