Power system small-signal stability region calculation method based on the guardian map theory

In view of the potential problems in the system such as sustained oscillation and low damping ratio, which are not considered in traditional small-signal stability region (SSSR), an improved SSSR (ISSSR) calculation method based on the guardian map is proposed. First, according to the map theory, the system is mapped from the ISSSR to the negative half-plane. Then by direct sum operation the guardian map is constituted. Finally, the guardian map approach, which is able to solve the exact stability region of the Hurwitz matrix, is used for fast and accurate calculation of the boundary of ISSSR. Simulation tests on the IEEE 4-machine 11-node system and 16-machine 68-node system verify the correctness and effectiveness of the proposed method. Besides, the influence of the generator excitation system parameters on the ISSSR is also analysed, which is highly valuable in system dispatching instruction and small disturbance instability prevention.