Browsing by Author "Antunes, Carlos Henggeler"
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- Direct Load Control in the Perspective of an Electricity Retailer – A Multi-Objective Evolutionary ApproachPublication . Gomes, Álvaro; Antunes, Carlos Henggeler; Oliveira, EuniceThe judicious use of end-use electric loads in the framework of demand-side management programs as valuable resources to increase the global efficiency of power systems as far as economical, technical and quality of service aspects are concerned, is a relevant issue in face of the changes underway in the power systems industry. This paper presents the results of a multi-objective optimization model, in the perspective of an electricity retailer, which is aimed at designing load control actions to be applied to groups of electric loads. An evolutionary algorithm is used to compute solutions to this problem.
- An Evolutionary Algorithm based on an outranking relation for sorting problemsPublication . Oliveira, Eunice; Antunes, Carlos HenggelerA new approach for using the preferences elicited from a Decision Maker (DM) into the operational framework of an Evolutionary Algorithm (EA) is presented. The preference representation is achieved using the parameters and principles of the ELECTRE TRI method devoted to the sorting problem. The outranking relation is used to replace the non-dominance relation in the usual operators in the EA (crossover, mutation and selection operator). The aim of this approach is to focus the search on the region of interest defined by the DM's preferences and consequently restrict the number of solutions in the Pareto-optimal front to be subject to further screening. This aspect is particularly important when dealing with problems that lead to a large number of non-dominated solutions.
- A hybrid multi-objective GRASP+SA algorithm with incorporation of preferencesPublication . Oliveira, Eunice; Antunes, Carlos Henggeler; Gomes, ÁlvaroA hybrid multi-objective approach based on GRASP (Greedy Randomized Adaptive Search Procedure) and SA (Simulated Annealing) meta-heuristics is proposed to provide decision support in a direct load control problem in electricity distribution networks. The main contributions of this paper are new techniques for the incorporation of preferences in these meta-heuristics and their hybridization. Preferences are included in the construction phase of multi-objective GRASP, in SA, as well as in the selection of solutions that go to the next generation, with the aim to obtain solutions more in accordance with the preferences elicited from a decision maker. The incorporation of preferences is made operational using the principles of the ELECTRE TRI method, which is based on the exploitation of an outranking relation in the framework of the sorting problem.
- A multi-objective simulated annealing approach to reactive power compensationPublication . Antunes, Carlos Henggeler; Lima, Paulo; Oliveira, Eunice; Pires, Dulce F.Reactive power compensation is an important problem in electrical distribution systems, involving the sizing and location of capacitors (sources of reactive power). The installation of capacitors also contributes to releasing system capacity and improving voltage level. A multi-objective simulated annealing approach to provide decision support in this problem is presented. This approach is able to compute a set of well-distributed and diversified solutions underlying distinct trade-offs, even for a challenging network. The characterization of the non-dominated front is relevant information for aiding planning engineers to select satisfactory compromise solutions (compensation schemes) to improve the network operation conditions.