Congestion Assessment for Transmission Planning in Competitive Electricity Markets

In competitive power markets, many factors influencing transmission planning change immensely. One of the problems needed to be solved imperatively is to work out new objectives and criteria applicable for electricity markets environment. Concepts of congestion performance index and validity index are presented in this paper. The indices utilize the level of congestion in the transmission network as the signals for transmission planning. The network expansion problem is decomposed into multi-phase-expansion subproblems. Network congestion can be relieved through solving a series of subproblems. Most seriously congested line can be determined easily by analyzing CPIs, which reduces the scope of candidate assembly and contributes to improve efficiency and quality of planning. The locations of added lines are determined by TVIs. This conduces to improving system economy and reliability. A simple network is developed to demonstrated how to assess expansion planning according to congestion signals