A Bi-level transmission expansion planning model considering the electricity market

The electricity market in China is changing from a regulated electricity market to a deregulated one, which activates the market entities to participate in the market. The flexible interaction among the market participants has posed great challenges for system operator as to consider the system expansion planning with high renewable energy penetration. Thus, to well integrate the influence of the electricity market, a bi-level model for transmission expansion planning is proposed in this work to guarantee the market fairness and investment economics. To achieve multiple objectives optimization, the cost to invest system infrastructures and the cost to maintain the daily operation of the power system is considered at the upper level, while the electricity market clear results can be obtained at the lower level. The local marginal price is therefore received to direct the way to expand the transmission network. Then, the Karush-Kuhn-Tucker condition is utilized to re-formulate the bi-level problem to a single level optimization problem. Thus, a mixed-integer nonlinear programming problem (MINLP) is presented and handled by a kind of Heuristic method. Moreover, the proposed framework is tested by a modified Garver-6 bus system, showing its good performance for expansion planning.