A Bi-Level Programming Model for Multistage Transmission Network Expansion Planning in Competitive Electricity Market

A new bi-level programming model of multistage transmission network expansion planning (TNEP) based on double-bidding based pool electricity market is presented in the paper. Open access transmission brings new challenges to transmission planning. From the transmission company's view, the goal of optimal transmission planning scheme should not only bring the optimal transmission profit in the market, but also ensure high operation security and reliability. In this paper, the upper level program considers transmission profit maximization in long-term planning, the lower level program considers the social welfare maximization in short-term operation. Furthermore N-1 security constraints are also considered in the model. A hybrid algorithm integrated with niche genetic algorithm and prime-dual interior method is used to solve the bi-level programming model of the transmission network expansion planning. Test results of the 18-bus system and real world 77-bus system show feasibility and right of the method.

I. Introduction

The transmission planning plays an essential role on providing a fair and competitive environment[1], [2] in competitive electricity market. Market-driven transmission investment or merchant transmission appears in power industry[3], [4]. Traditional regulated transmission expansion and planning would seek system-wide optimization striving for the social optimum. But the objective for transmission expansion planning in the deregulated environment is different from that in the traditional power industry. Although social welfare is necessary constraint to be accounted for, the transmission network owner or investor is more interested in maximizing their own profit. So traditional approaches to transmission planning are not suitable for the competitive market environment, this brings new challenge to transmission planning.