Delay-Dependent Wide-Area Damping Controller Considering Actuator Saturation and Communication Failure

Interarea oscillation is a major problem in modern interconnected power systems (ICPSs). It can be eliminated using a wide-area damping controller (WADC). It is well known that a wide-area signal is very effective as a feedback signal for the WADC to mitigate the interarea oscillation of an interconnected power system. Wide-area measurement systems (WAMS) are very useful to collect the wide-area signal, but communication delay and communication failure can occur at any time in WAMS using communication channels and can deteriorate the effectiveness of the WADC. A WADC that is resilient to communication failure is demonstrated in this work, contemplating transmission latency in the communication network and saturation of the actuator. The control action is developed using state feedback action, and a linear matrix inequality (LMI)-based condition is derived as the necessary condition to achieve stability in the power system. A supplementary damping controller (SDC) is used as the controller of a thyristor-controlled series capacitor (TCSC). The role of the actuator and WADC is taken by TCSC and SDC, respectively. The control algorithm ensures that the SDC supplies sufficient damping to enhance the small signal stability of the power system. The efficacy of the developed control algorithm is tested using an 11-bus system and an IEEE 39-bus power system.