The topology of power distribution systems can be modified by altering the status of sectional and tie switches for load management and protection, while maintaining the required network radiality. Several effective optimisation algorithms and graph theory-based techniques for system radiality detection have been proposed in specialised literature to solve the distribution network reconfiguration problem, usually seeking to achieve power loss reductions and voltage profile improvements. This work aims to contribute to this line of research and its novelties are composed of proposing as solution method a methodology based in an enhanced version of harmony search metaheuristic called improved harmony search algorithm, and a new simple and effective system impedance matrix based process to detect islanding of nodes as a strategy to meet radiality constraint. The proposed methodologies were applied to 33-bus, 84-bus and 118-bus distribution networks known from technical literature, aiming to total active power loss minimisation. As comparison between methods, a key focus in analysis of results is related to discuss some advantages and effectiveness of improved harmony search over original harmony search algorithm to attain optimal radial topologies.

This paper addresses the problem of Distribution Systems Reconfiguration (DSR), which consists of finding the state of switching devices (open or closed) in a given distribution network, aiming to minimize active power loses. DSR is modeled as a mixed-integer non-linear optimization problem, in which the integer variables represent the state of the switches, and the continuous variables represent the power flowing through the branches. Given the multi-modal and non-convex nature of the problem, an improved harmony search (IHS) algorithm is proposed to solve the DSR problem. The main novelty of this approach is the inclusion of a Path Relinking phase which accelerates convergence of the DSR problem. Several tests were carried out in four benchmark distribution systems, evidencing the effectiveness and applicability of the proposed approach.

In this paper, an optimal insertion strategy model of power plant units from a Distributed Generation portfolio is proposed. The study is based on a multiobjective formulation involving economical, technical and environmental aspects, and it consists of determining the quantity of units of each power plant that will be inserted in a distribution network by planning stage, considering some known specifications, expansion sceneries and constraints. The modeling aims to obtain a Pareto frontier set of solutions, which is addressed utilizing a multiobjective Particle Swarm algorithm and the Maximin metric. An application example is presented to test the proposed procedure; a metric to measure the diversity of the obtained frontier is employed, and the Max-Min approach is used as decision criterion.

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The expansion of the electric power system by large central generators linked to end consumers through extensive transmission lines, at an ever-increasing voltage, points toward a complementarity and an ever-increasing participation of Distributed Generation (DG). In this manner, there is a need to define criteria and technical criteria for the assessment of DG projects that ensure returns on investment. This article proposes a modeling of technical criteria through multiattribute value functions to analyze the technical benefits stemming from DG projects. To accomplish this goal, a multicriteria methodology will be applied which allows for the simultaneous treatment of the diverse technical aspects necessary in the planning and decision-making processes, as well as the implementation of the Utility Theory to define a behavior that is averse, willing or neutral to a determined criterion.