Wide area control framework design considering different feedback time delays

In this paper, a framework for a real-time wide area controller is established for damping small-signal instability related events in interconnected power systems. Offline designing is performed to design the centralized controller for each inter-area mode of the power system. Residue approach is used to select the most effective stabilizing signals and controller locations. Different constant time delays are taken into controller parameters design. Thus an offline controller database is formed, including different controllers of each mode. The parameters of each controller are different for various ranges of time delay. The damping and other mode information will be identified by online multi-Prony analysis. When an inter-area mode is detected with weak or negative damping, say less than 3%, the corresponding controller for the detected mode will be initiated and deployed for enhancing the damping of the problematic mode. The time delay, which is used to select a suitable set of parameters for a chosen controller, could be calculated online, using the time stamps of the actuator and feedback signal. The paper proposes the framework of the controller with preliminary discussions on the various components of the controller, including: 1) the offline controller database, 2) the online detection of undamped oscillations, and 3) the online corrective control actions at the actuator. The 4-machine 2-area case study results demonstrated the advantage of the proposed method.