In this paper, the transmission planning state-of-the-art, which was obtained from the review of the most interesting models found in the international technical literature, is presented. The classification of publications was made, keeping in mind the solution methods, the treatment of the planning horizon, and the consideration of the new competitive schemes in the power sector. A discussion about the available tools for development of transmission planning models is also included.

Classification of publications and models on transmission expansion planning

It will be important to develop a transmission network capable of handling future generation and load patterns in a deregulated, unbundled, and competitive electricity market. A new strategy for transmission expansion under a competitive market environment is therefore presented in this paper. In the proposed strategy, a new transmission planning model is developed to consider a variety of market-driven power-flow patterns while a decision analysis scheme is incorporated to minimize the risk of the selected plan. Numerical examples are given to illustrate the potential of the proposed strategy to make a significant contribution to transmission planning in competitive markets.

A new strategy for transmission expansion in competitive electricity markets

This paper proposes a method for choosing the best transmission system expansion plan considering a probabilistic reliability criterion (/sub R/LOLE). The method minimizes the investment budget for constructing new transmission lines subject to probabilistic reliability criteria, which consider the uncertainties of transmission system elements. Two probabilistic reliability criteria are used as constraints. One is a transmission system reliability criterion (/sub R/LOLE/sub TS/) constraint, and the other is a bus/nodal reliability criterion (/sub R/LOLE/sub Bus/) constraint. The proposed method models the transmission system expansion problem as an integer programming problem. It solves for the optimal strategy using a probabilistic branch and bound method that utilizes a network flow approach and the maximum flow-minimum cut set theorem. Test results on an existing 21-bus system are included in the paper. They demonstrate the suitability of the proposed method for solving the transmission system expansion planning problem subject to practical future uncertainties.

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A method for transmission system expansion planning considering probabilistic reliability criteria

The new challenges to transmission expansion planning. Survey of recent practice and literature review

Transmission switching (TS) is introduced to add flexibility to the transmission and generation capacity expansion planning problem. TS could improve the performance of the capacity expansion planning model and reduce the total planning cost. The capacity expansion planning problem is decomposed into a master problem and two subproblems. The master problem utilizes the candidate set for additional generating unit and transmission capacity investments to find the optimal plan throughout the planning horizon. The subproblems use the optimal plan, apply transmission switching to relieve any transmission flow violations, and calculate the optimal dispatch of generating units. The transmission network contingencies are also considered in the subproblems. The case studies exhibit the effectiveness of the proposed expansion planning approach.

Transmission Switching in Expansion Planning

A new method is proposed in this paper to solve a single-stage expansion problem for a transmission network, given future generation and load patterns, and alternative types of lines available, subject to overload, reliability and right-of-way constraints. The problem is formulated as a series of zero-one integer programs which are solved by an efficient branch-and-bound algorithm. Complexity is reduced by the concepts of optimal cost-capacity curves and screening algorithms. A sample study is shown and the method is implemented in a computer program.

Transmission Expansion by Branch-and-Bound Integer Programming with Optimal Cost - Capacity Curves

A three-area loss-of-load probability theory is presented which forms the basis of a practical working computer program. The method applies specifically to electric power systems within which transmission limitations exist. Existing single-area techniques assume no transmission limitations. A method recognizing tie-line limitations between two areas was published in 1963 [1].

Kenneth L. Hicks

Papers

Transmission Expansion by Branch-and-Bound Integer Programming with Optimal Cost - Capacity Curves

Probability of Loss of Load for Three Areas