Power system transmission network expansion planning using AC model
ABSTRACT An optimisation technique to solve transmission network expansion planning problem, using the AC model, is presented. This is a very complex mixed integer nonlinear programming problem. A constructive heuristic algorithm aimed at obtaining an excellent quality solution for this problem is presented. An interior point method is employed to solve nonlinear programming problems during the solution steps of the algorithm. Results of the tests, carried out with three electrical energy systems, show the capabilities of the method and also the viability of using the AC model to solve the problem.
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ABSTRACT: The expansion plan obtained from a DC model based transmission expansion planning (TEP) model could be problematic in the AC network because the DC model is potentially inaccurate. However, solving TEP problems using the AC model is still extremely challenging. The motivation for this work is to develop a less relaxed network model, based on which more realistic TEP solutions are obtained. The proposed TEP model includes a linear representation of reactive power, off-nominal bus voltage magnitudes and network losses. Binary variables are added to avoid fictitious losses. Garver's 6-bus system is used to compare the proposed TEP model with the existing models. An iterative approach for considering the N -1 criterion during the planning process is developed and demonstrated on the IEEE 118-bus system. Simulation results indicate that the proposed TEP model provides a better approximation to the AC network and is applicable to large power system planning problems.IEEE Transactions on Power Systems 08/2013; 28(3):3471-3479. DOI:10.1109/TPWRS.2013.2250318 · 3.53 Impact Factor
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ABSTRACT: Operational planning of power systems, especially in terms of overall reliability and security, is a key issue in the smart grid development. Hence, it is necessary to develop new strategies to cope with increasing uncertainties arising from the fast changing ways power systems are being operated. This paper presents a comprehensive approach to determine an optimal transmission network expansion plan considering the enhancement of small-signal stability through wide-scale deployment of the existing and planned transmission system assets. The dynamic model of the transmission network operational planning (TNOP) is solved based on a combination of the Mean-Variance Mapping Optimization (MVMO), and the classic dynamic programming method embedded with a heuristic procedure. Besides, a probabilistic eigenanalysis-based recursive method is proposed to determine the optimal control strategies that are highly relevant to the enhancement of the system small-signal stability performance throughout the planning horizon. Numerical results demonstrate the viewpoint and the effectiveness of the proposed approach in providing optimal strategies of minimum cost while avoiding the instability risk associated to poorly damped low-frequency electromechanical oscillations.IEEE Transactions on Power Systems 03/2013; 4(1):530 - 539. DOI:10.1109/TSG.2012.2222678 · 3.53 Impact Factor
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ABSTRACT: Transmission expansion planning (TEP) is a rather complicated process which requires extensive studies to determine when, where and how many transmission facilities are needed. A well planned power system will not only enhance the system reliability, but also tend to contribute positively to the overall system operating efficiency. Starting with two mixed-integer nonlinear programming (MINLP) models, this paper explores the possibility of applying AC-based models to the TEP problem. Two nonlinear programming (NLP) relaxation models are then proposed by relaxing the binary decision variables. A reformulation-linearization-technique (RLT) based relaxation model in which all the constraints are linearized is also presented and discussed in the paper. Garvers's 6-bus test system and the IEEE 24-bus system are used to test the performance of the proposed models and related solvers. A validation process guarantees that the resultant TEP plan is strictly AC feasible. The simulation results show that by using proper reformulations or relaxations, it is possible to apply the AC models to TEP problems and obtain a good solution.Power and Energy Society General Meeting, 2012 IEEE; 01/2012