Wide area measurement/wide area information-based control strategy to fast relieve overloads in a self-healing power grid

Self-healing is one of the characteristics of the smart grid. A self-healing power grid can identify and react to disturbance and restore power systems with little or even no human intervention. A wide area measurement (WAM) and wide area information (WAI)-based control strategy is proposed to fast react to overloads and restore the power grid in the self-healing power grid. The basic principle is to redistribute the power flow of a contingency transmission line to other lines with unified power flow controller (UPFC). To implement the control strategy, the reverse current network and nodal analysis method, instead of the iteration algorithm and optimisation method, is applied to redistribute the power flow. The proposed WAM/WAI-based nodal analysis can relieve overloads quickly and effectively while realising the control objective accurately. Moreover, a grid simplification method is applied to further reduce computation cost. IEEE 39-bus test system-based simulation is applied to verify the proposed control strategy. The results show that the control strategy can relieve overloads effectively in about tens of milliseconds. Thus, it could be an online controller for a self-healing power grid to deal with harmful contingencies.