Decentralized coordinated robust controller design for multimachine power system based on multi-agent system

A decentralized coordinated control is researched based on multi-agent structure for transient stability improvement of large-scale power system in this paper. First, a multi-agent system (MAS) model is structured based on the wide-area measurement system (WAMS), which consists of both upper and lower level agents. The upper level coordinated agents are mainly responsible for coordinating and controlling the lower level agents via sending coordinated control signals into local decentralized control loops in order to damp lower frequency oscillations between regions. And the main function of lower level agents is to continuously regulate generator unit through excitation controller to overcome small disturbances. Then, the focal task of this paper is to design a decentralized coordinated controller based on the MAS model. To eliminate the nonlinearities and interconnections of multimachine models, a direct feedback linearization (DFL) compensator is designed through the decentralized excitation control loop. Besides, taking consideration of the effects of uncertainty introduced by transient process, the H∞ robust control method integrating with linear matrix inequality (LMI) technology is used to seek the solutions of the decentralized coordinated controller. Finally, simulation demonstrates that the MAS based decentralized coordinated robust controller has better transient stabilization performance than the conventional PSS.