Coordinated scheme for expansion planning of transmission system with active distribution system flexibility provision

Abstract

The extensive access of distributed renewable energy at the level of distribution network makes the distribution grid have the ability of active regulation similar to the transmission grid, and the power exchange between transmission and distribution systems becomes more flexible bidirectional. In order to make full use of the complementary collaboration ability between the distribution and transmission systems, this paper proposes a flexible planning method of transmission system coordinated with distribution system for the future scene of high proportion renewable energy. This collaborative optimization framework is a double-layer structure: The upper layer goes on the expansion planning of transmission system, and the lower layer goes on the operation simulation of distribution grid. The upper-level model transfers the marginal price of nodes to the lower-level model, and the lower-level model feeds back the purchase and sale agreement to the upper model. The linear transformation of the model is deployed using piecewise linearization and big-M method. We use the strong duality theory to transform the original double problem into an equivalent single-layer form, and then the effective solution of the commercial application is realized. Aiming at the high proportion renewable energy in transmission and distribution systems, the performance of the formulated problem is validated by comparative analyses of examples.

Keywords

• Transmission system planning
• Distribution system operation
• High proportion of renewable energy
• Double-layer collaborative optimization
• Strong duality theory