A Control Strategy to Fast Relieve Overload in a Self-healing Smart Grid

Self-healing is one of the characteristics of smart grid. The self-healing functions could enable a power grid to detect the event in advance and restore the system after contingencies with minimum damages. In this paper a control strategy to fast relieve overload in the self-healing smart grid is proposed. The basic principle of the control strategy is to redistribute power flow of a contingency transmission line to other lines by using unified power flow controller (UPFC). To implement the control strategy, distributed steady-state network and wide-area measurement (WAM) -based nodal analysis are proposed and applied to redistribute power flow. The proposed WAM-based nodal analysis is carried on to relieve overload quickly and effectively while realize the control objective accurately. Moreover, grid simplification based on controllable region analysis is applied to reduce computation burden. IEEE 39-bus test system based simulation is applied to verify the proposed control strategy. The results show that the control strategy can relieve overload quickly and effectively. Thus it could be an online controller for a self-healing smart grid to deal with harmful contingencies.