A Coupled Model to Multistage Transmission Expansion Planning

Abstract

This paper proposes a new approach to solving the multistage transmission line expansion planning problem. The proposed formulation incorporates decisions about where and when reinforcements should be placed to fit the desired demand. To accomplish that a expansion decision variable (ED) is incorporated into an integer, coupled and extended DC optimum power flow (I-COPF). The proposed I-COPF problem can be solved by using any commercial software for integer programming, but to reduce the computational complexity of this integer problem, a new heuristic method is presented. So, the integer problem is broken by adopting two steps: (i) the I-COPF is transformed into a continuous problem (C-COPF) by using a ED as continuous variable. This step provides a set of ED and the Lagrange multipliers for all planning period. The step (ii) uses the response provided by (i) to determine the optimal reinforcement set. These two steps are solved interactively during the planning horizon. To demonstrate the effectiveness of the proposed methodology, the results of three systems will be compared with a numerical-based approach provided by a commercial software and other academic researches.