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Configuration of distribution system can be changed manually or automatically, by changing the status of the respective switching elements, with the aim of reducing power losses, increase system reliability, or improving the power quality. When changing the status of switching equipment it is necessary to satisfy the requirement for the radial and connected structure of the distribution network. Using the single criteria optimization it is possible to improve one of the characteristics of the distribution network, on the other hand by using multicriteria optimization it is possible to find a network configuration that enhances multiple distribution system characteristics at the same time. In this paper, a modification of the multi-criteria Gray Wolf optimization algorithm is proposed in order to create an efficient algorithm that can be implemented in the management functions of smart grid concept of modern distribution systems. The proposed reconfiguration algorithm was tested on standard symmetrical IEEE 33 test distribution network.

A new concept of switches selection in the meta-heuristic optimization process of optimal distribution network reconfiguration has been proposed. Based on the adaptive set of selectable candidates, the proposed concept determines the switch status. This approach prevents the creation of unfeasible solutions (non-radial and unconnected configurations), and significantly reducing the number of searches and accelerating the optimization process. Unfeasible solutions, created by meta-heuristic optimization rules, can be corrected by means of the proposed adaptive loop concept. The correct parts of the unfeasible solution are retained, while only the defective parts are replaced by the adaptively formed loops from the currently available conditions that respect the correct switching operations. In this way, the basic characteristics of the optimization process have been retained to the greatest possible extent. Tests were performed on a two different size standard distribution networks.

This paper presents an educational software tool with a user-friendly interface, which can be used for evaluation of available transfer capability (ATC). The software was developed using the MATLAB 1-2 software package. The software is designed for engineers who are involved in trading in electrical energy and for students (undergraduate and Master's) of Electrical Engineering who could, by using the software, gain a better insight into the theoretical knowledge and solve some practical engineering problems. ATC model limitations include the usual d.c. load fl ow inherent limitations as well as line thermal limits, prevalent in the literature on ATC. The structure and software capabilities are presented within the example of an ATC sensitivity study on a fi ve node/seven line transmission network, used for zonal market activities tests.