Abstract:

A design method was proposed for multi-loop DC coordination damping controller, which used subspace identification to reduced order modeling for system, used genetic algorithm for parameter optimization, and estimated the stability of time-delayed system. Firstly, the wide-area input signal of DC controller was selected by using dominate mode ratio index calculation method based on Prony analysis； the input and output data of the system under disturbance were obtained according to the simulation； and the open-loop state space equation was obtained by system subspace identification based on the data. Secondly, adding the controller in the open-loop system to get closed-loop system state space equation. Moreover, with maximizing the minimum damping ratio of the system under various operation modes as the optimization goal, genetic algorithm was used to coordinately optimize the controller parameter in closed-loop system state space equation. The stability criterion of system with time-delay based on free-weighting matrices was used to analyze the stability of system with time-delay for wide-area power system with multi-loop DC coordination controller. Finally, taking China Southern Power Grid as an example, the multi-loop DC coordination damping controller was simulated. The simulation results show that the multi-loop DC coordination damping controller obtained by this method can better improve the damping level of power gird, and meet the requirements of the stability of time-delayed system.

Key words: subspace identification, genetic algorithm, coordination controller, coordination optimization, stability of time-delayed system