HVDN Line Switching for Alleviating Transmission Congestion with the Integration of Electric Vehicles and Wind Farms

Transmission congestion is considered as a serious security problem that limit the efficiency of the transmission systems. Due to the lack of controlling measures in some part of the transmission network, much load shedding amount and controlling cost would be required to alleviate the congestion. As more and more renewable energy resources integrate into the grid, the transmission lines are prone to be overload. Whereas in high voltage distribution network (HVDN), each substation usually has one or two reserve lines that connect to another power supply point thus greatly enrich the operation flexibility of HVDN. By changing the topological structure of HVDN, the load in transmission network can be greatly redistributed. In order to improve the transmission efficiency and reduce the total controlling cost, a generator rescheduling scheme considering line switching of HVDN was proposed in this paper. The model consists of a generator rescheduling model and a second order cone programming (SOCP) based HVDN line switching model. An urban test system in China was utilized to verify the effectiveness of the proposed method. Numerical results show that utilizing the HVDN line switching to transfer the load dramatically reduce the load shedding amount and controlling cost.