Design of WAMS-based SVC robust controller considering time delay uncertainty of remote signals

Wide area measurement system (WAMS) prepares and transmits the measured remote signals of a whole power system to wide area controller (WAC) to achieve an effective inter-area oscillations damping. One of the main issue is the existence of transfer time delay in WAC input signals which can degrade the damping performance of WAC. One way to overcome this problem is to consider time delay in the controller design procedure to ensure effective control of WAC. In this paper, time delays are modeled by padé approximations and the time delay uncertainty is described by linear fractional transformations (LFT). The synthesis of the WAC is defined as a problem of H∞ mixed sensitivity control and is resolved by the linear matrix inequality (LMI) approach. The simulation results on 16-machine 68-bus system show that the WAC designed to provide a supplementary control signal of SVC, has satisfactory performance in a wide range of time delay.