Stability of an Adaptive Switched Controller for Power System Oscillation Damping using Remote Synchrophasor Signals

This paper is concerned with the stability of an adaptive switched controller for interarea power system oscillation damping using remote signals. These signals introduce variable latency into the damping control system due to phasor processing and communication network delays. In previous work, we designed an adaptive controller that dynamically switches among different compensators depending on the latency of the incoming measurements. To prevent switching instability, a long reset time was implemented. We demonstrated the stability of the adaptive system using simulations. In this work, we use the concept of average dwell time (ADT) of switched control systems to develop a sufficient condition that guarantees the stability of our adaptive switching algorithm. Using this condition, we formulate a feasibility problem to compute the minimum average dwell time for the set of designed compensators. We apply the algorithm to a thyristor-controlled series compensator on a two-area power system and show that the adaptive controller is stable for time-varying latency.