OBSERVATIONAL LINEARIZATION AND OPTIMAL HVDC SUPPLEMENTARY CONTROLLER BASED ON PHASOR MEASUREMENT UNIT

To enhance dynamic stability of AC/DC power systems an observational linearization and optimal HVDC supplementary controller based on Phasor Measurement Unit (PMU) is proposed. This controller utilizes the real-time state variables obtained by PMU to linearize the state equations of the system, and then the linear optimal control strategy is used to design HVDC supplementary controller. Compared with the controllers based on the models linearized in one operation point, the non-linearity of the system is considered in the presented controller, and its control rule varies with the real-time status of the system. From the results of small signal stability analysis of single-machine infinite-bus (SMIB) AC/DC parallel system and time-domain simulation it is proved that the presented optimal close-loop controller can enhance the dynamic stability of the system and the AC system抯 transmission capability over a wide range of operation conditions, and the robustness of this proposed controller is better than that of single-input single-output head-lag controller.