Stability Analysis of Wide Area Damping Controllers with Multiple Time Delays

The paper discusses the impact of multiple time delays on the stability of centralized wide area damping controllers (WADCs). These controllers are utilized in electric power systems to damp the interarea oscillations. With this aim, an ideal WADC is first designed based on the well-known H∞ control scheme. Then delays are included for all remote signals of the WADC and different delay models, namely, constant, stochastic and periodic delays with dropout, are considered and compared. Both nonlinear time domain simulations and closed-loop eigenvalue analysis based on the 2-area test system are carried out. Finally, a probabilistic method to evaluate the impact of stochastic communication delays on small-signal stability is discussed.