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Abstract: Reactive flows compensation optimal design for losses reduction in MV automated distribution systems is a problem deeply studied in literature. In this paper, the design problem is formulated considering the new deregulated energy market. These new operational conditions allow the MV grid operator to consider the generation of reactive energy also as a service that can be sold to the transmission system above. In this case, the transmission system would be helped in all the working conditions in which a strong modulation of the reactive flow through the HV/MV node is required. Then, for the MV grid operator, the compensation system optimal design problem is therefore that of the search for the configuration (number, location and rated power of the capacitor banks) attaining the following main objectives: (i) to minimise power losses; (ii) to maximise the return on investment for the compensation system. Since results are strongly influenced by the parameter ‘economic value given to the reactive power’, RPEV, flowing from the MV network through the HV node, the optimisation problem has been parameterised for different values of RPEV and the total installed reactive power has been observed. A threshold value of this parameter has been identified. For values greater than the threshold, the proposed investment is economically profitable for the distribution grid operator, DGO. [Copyright &y& Elsevier]

Abstract: A methodology for the analysis of radial or weakly meshed distribution systems supplying voltage dependent loads is here developed. The solution process is iterative and, at each step, loads are simulated by means of impedances. Therefore, at each iteration, it is necessary to solve a network made up only of impedances; for this kind of network, all the voltages and currents can be expressed as linear functions of a single unknown current (in radial systems) or of two unknown currents for each independent mesh (for meshed systems). The methodology has been called “backward” since the unique equation, in case of radial network, and the linear system of equations, in case of meshed network, in which such unknown currents appear can be determined by starting from the ending nodes of the radial system, or of the radialized network (obtained by means of cuts in meshed networks). After a brief presentation of the b/f method, which is currently the most commonly used technique for solving distribution networks, the solution methodology is detailed both for radial and for meshed systems. Then, the way in which PV nodes can be considered is also described. Finally, the results obtained in the solution of some networks already studied in the literature are presented with other methods, in order to compare their performances. The applications show the efficiency of the proposed methodology in solving distribution networks with many meshes and PV nodes. [Copyright &y& Elsevier]