Coordinated planning method of multiple micro-grids and distribution network with flexible interconnection

Highlights: • Coordinated planning method is proposed for micro-grids and distribution networks. • FID can enhance the power-flow controllability and reduce ES installation. • The optimal planning model requires investments as well as system operation cost. • Benders decomposition is used to separate the design and operation variables. • The case study shows advantages of flexible interconnection and planning model. This work explores the coordinate planning methods for multiple micro-grids in different distribution transformers and networks with flexible interconnections. The optimal planning model considers in detail the coupling influence of the interconnection structure, investment, installed capacity and annual operation cost. The interconnection structures of multiple micro-grids with different distribution transformers are discussed, and the flexible interconnection device (FID) model is established. Then, multiple micro-grids with the FID interconnection planning model is proposed, which is considered to include the connection type, investment cost and hourly operation dispatches. In order to solve the complicated combinatorial bi-level layer planning model, the benders decomposition methods are used to divide the problem into an investment decision-making master problem and an operation optimal sub-problem. A study case which is based on six micro-grids in three distribution transformer areas is used to carry out the planning methods, and simulation results show that the proposed model and methods are effective, and have some technical and economic advantages.