C I R E D 18 th International Conference on Electricity Distribution Turin, 6-9 June 2005 CIRED2005 Session No 5 DISTRAPLAN: A FLEXIBLE TOOL FOR STRATEGICAL PLANNING OF ELECTRICAL DISTRIBUTION SYSTEMS CONSIDERING DISTRIBUTED GENERATION L.S. BAGGINI, G. BOTTA CESI, Milano-Italy (Baggini, Botta)@cesi.it M.G. IPPOLITO, G. MORANA, E. RIVA SANSEVERINO, F. VUINOVICH Dipartimento di Ingegneria Elettrica, Università di Palermo – Italy (Ippolito, Morana, Eriva, Vuinovich)@diepa.unipa.it INTRODUCTION The paper here presented describes and shows DISTRAPLAN (Distribution Strategical Planning), software tool for strategical planning of distribution networks at Medium and Low voltage. The software aims at the identification and comparison of network configurations, optimized in the long term with identification of special features in relation to the main technical-economical-environmental aspects, such as: the number of HV/MV and MV/LV substations, total length of the MV and LV lines and relevant sections, maximum required energy and power, installation and losses costs, etc. DISTRAPLAN, in both the main procedures into which it is articulated (strategical planning and evaluation of the minimum consistency of the networks) uses heuristic optimization algorithms, namely genetic algorithms suitably adapted to treat the problem at hand. THE SOFTWARE DISTRAPLAN In the current evolution and innovation process of the Italian electrical system, aimed at the improvement of the quality, security and economy levels, the transformation and development of distribution systems get a growing importance. Distribution systems are indeed in contact with customers and environment and are the place where Distributed Generation, DG, is being installed more and more. Therefore, these changes require adequate tools to analyze and compare possible scenarios of development of distribution systems in the medium and long term, with a methodological approach which is typical of strategical planning studies. This approach is based on particular modelling techniques and on the use of specific optimization algorithms. In this paper, the software DISTRAPLAN (Distribution Strategical Planning) is presented. This software tool is designed to perform strategical planning of MV and LV networks, and has been implemented within a co-operation between the CESI (Centro Elettrotecnico Sperimentale Italiano) and DIE (Dipartimento di Ingegneria Elettrica) of the University of Palermo, in the frame of the project SCENARI for the system research in Italy. DISTRAPLAN is aimed at the identification and comparison of long-term optimized network configurations with the identification of specific features in relation to the main technical-economical- environmental aspects, such as: - total length of the MV and LV lines and relevant sections; - number of MV/LV substations; - number of HV/MV substations; - maximum output power and energy yearly required by MV and LV networks at the primary substations; - costs related to the cited components and to the network; - indices for service continuity, etc. The methodological approach here followed is of modular type, based on the employ of functional models and on the modular combination of these models for the representation and the optimization of the entire distribution system [1] [2] [3] [4] [5]. Each module is representative of the structure and of the operational trend of each stage composing the electrical system also with structural singularities such as dispersed generation resources [6] [7] [8]. The study is performed under the preliminary assumption that the entire territory can be decomposed in areas (urban electrification areas at large/medium/small concentration, industrial, commercial, rural areas, etc.), identified within a province and characterized by a uniform electrical load density (in terms of yearly required energy), as well as by other specific characterization data. For the different areas, DISTRAPLAN allows to consider the presence of DG, in particular: - from primary aleatory sources (such as Photovoltaic) at LV; - from primary non aleatory sources (such as microturbines, cogeneration, biomass,… ) at MV; For each area and for each scenario (load evolution, degree of penetration of DG, etc..) and for each set of ‘free’ choices of the planner (type of structural modules, values of the constraints, etc.), DISTRAPLAN gives configurations of the distribution system that are optimized in the entire considered time frame. The comparison of the total costs associated to each chosen configuration identifies the ‘best’ configuration for each considered scenario, namely the set of characteristic choices implying the minimum total cost per squared kilometre. In order to make more evident the potential direct effects of the different scenarios on the consistency of the distribution systems, else than the optimal configuration related to each scenario, DISTRAPLAN also gives, year by year, within the studied time frame, the minimum consistency of the distribution system in terms of: • Minimum number of primary HV/MV and secondary MV/LV substations, for any given electrification territory and relevant load characterization data;