Research on time-delay stability upper bound of power system wide-area damping controllers based on improved free-weighting matrices and generalized eigenvalue problem

A novel method is proposed in this paper to determine the time-delay stability upper-bound of the power system with wide-area damping controllers based on the improved free-weighting matrix and Generalized Eigenvalue Problem (gevp). First, a new class of Lyapunov-Krasovskii functional is constructed and its derivative function along the system is gained. Second, necessary loose items are added to the derivative function to reduce conservativeness, and the time-delay stability criterion based on the improved free-weighting matrices is formed. And then the time-delay stability criterion is equivalently transformed to a generalized eigenvalue problem. Thus by solving the gevp, the time-delay stability upper bound of the system is gained. Time-domain simulation tests on the IEEE 4-machine 11-bus system and IEEE 16-machine 68-bus system verify the correctness and effectiveness of the method.