Bi-Level Transmission Expansion Planning Considering The Transfer Capacity of Hybrid AC/DC Interface

With the increasing integration of HVDC tie-lines, the regional power systems in both the energy-exporting area and the energy-importing area have gradually become the “strong DC, weak AC” power system. A bi-level transmission expansion planning optimization model is proposed in this paper for network reinforcement of energy-exporting power grid with hybrid AC/DC interface. While existing literature has not considered the transient stability problem in TEP, we use the conventional total transfer capacity (TTC) index to evaluate the security limit of hybrid AC/DC interface under different transmission expansion schemes. The optimization model for TTC computation is embedded in the lower level. The solution approach is then proposed for the bi-level TEP model. Simulation results on the modified IEEE 39-bus system demonstrate that the planning scheme by the proposed bi-level model can ensure the secure operation under severe contingencies in comparing with conventional model.