A Coordinated Planning Model for AC-DC Distribution System and Renewable Energy Integration with High Reliability

The requirement for large-scale renewable energy integration promotes the upgrading of distribution system from single AC system to hybrid AC-DC system. In order to improve the penetration of renewable energy located in remote areas, this paper proposes an AC-DC configuration where the renewable energy generated by distributed generators is collected through a DC system and transmitted to the AC distribution system through several collection lines. The planning model aims to minimize the total investment and operating costs over the planning horizon. A second order conic programming is introduced to formulate the optimal power flow in AC-DC distribution system. The reliability of DC system in dealing with N−1 contingency is further improved from the aspect of topology. Numerical simulations on a test AC-DC distribution system demonstrate the validity of the proposed planning model.