H∞ control of inter-area oscillations based on WAMs considering signals transmission delay

The paper proposes an adaptive supervisory controller (ASC) to enhance the damping of inter-area oscillations using wide area measurement (WAM) and accounting for signals transmission delays. The damping controller based on the mixed-sensitivity linear matrix inequality (LMI) approach with pole-placement restriction is designed. In the controller design, the signal transmission delays are regarded as structured uncertainty with linear fractional transformation (LFT) approach. The design of the ASC is explained in detail and its performance validated for a range of operating conditions by frequency and time domain simulations on a 4-machine 2-area test system.