Wide-area power oscillation damping with a fuzzy controller compensating the continuous communication delays

Recent technological developments in the wide-area measurement system (WAMS) are realizing centralized controls for improving the power systems stability. The most challenging barrier against these advances relates to communication delays, which are not constant and depend on information system loading. Neglecting this latency could deteriorate the damping performance of closed loop control or even degrade the system stability. This paper designs a fuzzy logic wide-area damping controller (FLWADC) to damp the inter-area oscillations compensating for the continuous latency. The controller is based on the fuzzy logic due to its proven robustness against input signal variations. The proposed controller has three input signals consisting of angular difference, its derivative, and the time latency, which is precisely determined through measured data time tags and the accurate time signal at the controller location. Rule bases of FLWADC are developed such that membership functions of the output variable are accordingly shifted to compensate for the time delay. A standard test bed for dynamic simulations and its expanded version are examined, and numerical evidences are discussed. To generalize the conclusions drawn in the case study, various sets of sensitivity studies are conducted, covering controller parameter changes, power system reconfigurations, and shifting the system operating point.