Design of HVDC supplementary controller accommodating time delay of the WAMS signal in multi-machine system

In this paper a novel HVDC supplementary controller based on WAMS was proposed which accounts for delayed arrival of the signal. The controller performance deteriorates considerably if the time delay involved in the data transmission is much more than the time period corresponding to some critical inter-area modes. In this paper, causes of transfer delay and their influence on the HVDC supplementary controller were analyzed. A new controller was then designed based on the linear matrix inequality (LMI) theory in order to account for the time delay effect. Performance of the new controller was compared with the controller that doesn't account for time delay effect. The design method was extended to multi-machine system and the simulation results showed that the method is feasible and effective.