Framework proposal for selecting a hybrid renewable generation mix at a prosumer connecting point in the context of micro smart grids

Abstract

Considering the thematic of climate change, numerous strategies have been adopted in order to struggle with such problem. In electrical systems and power supply, the use of clean technologies is considered the mostacceptable solution. In thiscontext,emergesthe concept of microgrids (MGs). MGs are local energy providers that can potentially reduce energy expenses and emissions by utilizing distributed energyresources(DERs). A mong a variety of DER susedon microgrids,it is widelyac cepted that renewable sources, especially solar and wind generation, play a significant role in providing sustainable energy, as they are both inexhaustible and less polluting. Because of that, the microgrids and renewable energy sources are receiving increasing attention from power system operators, since they can aid to transform the current high pollutant power system into a "greener"system.How ever ,there is still much to beconsidered and proven in relation to the implementation of such technologies. The intermittent nature and the uncertainties associated with solar and wind generation pose sufficient technological and economical challenges for system planners. Besides, the supply of electricity interferes the society as a whole, which makes the implementation of microgrids and renewable energies an even more complex problem, dependent on a wide spectrum of players, interests and constraints. In this context ,the present work is a first effortin establis hing a frame work that is capable of dealing with such heterogeneous problem. More than that, this thesis contributes with a broader view of microgrid implementation, suggesting a collection of tools which are suitable for observing the effects of penetration of clean technologies on society. The proposed frame work is afivestage planning strategy which allows the system planners to consider all aspects ranging from uncertainty in resources, technological feasibility, economics, and environmental impacts of the system and choose an optimal design suited to their localized conditions. The motivation behind using such strategy lies not only in the optimization of the individual systems or disciplines but also their interactions between each other. In short, the suggested approach is an iterative procedure divided in five stages, named microgrid coordination, operation optimization, reliability assessment, contingency assessment, and searching mechanism. The microgrid coordination stage has the function of modeling the philosophy used by the energy management system (EMS) to control the power balance in microgrids. The models of EMS are developed using the Petri net formalism. Optimization stage performs a constrained cost minimization analysis of microgrid considering the operation and maintenance (O&M) cost, pollutants emission, and stoc hastic variables(generation and loaddemand).Afte rthat ,it is executed the reliability assessment ,where the power system reliability indexes are estimated by means of a Monte Carlo Simulation (MCS),taking into a ccount the EMS philosophy of microgridin isolated mode. Next, using the reliability indexes, the contingency probability is calculated using the steady state analysis of a Markov chain, which aims to assess the distribution power system admitting all possible mode transition. Finally, since the DER selection involves multiple criteria and interests of different parts, it is required a multi-attribute decision system providing a list of possible configuration based on their relative importance as denoted by the stakeholders. Because of that, the Particle Swarm Optimization (PSO) is used to search the best DER combination using two distinct solvers - multi-objective weighted function and Pareto front. As result, the framework provides the rated power of each DER that must be installed in the microgrid in order to have an optimal balance between technical, economical, social, and environmental aspects. Regarding the heterogeneous quality of planning problem, this strategy is effective in the sense of incorporating several aspects into the same analysis framework. In addition, the proposed framework contributes helping the planners to handle the penetration of renewable resources in a systematic way. To have realistic results, the framework is performed on a case of study of a potential campus microgrid program.