Microrrede conectada à rede elétrica para alimentação ininterrupta de cargas CC

Abstract

This Master's dissertation presents a comparison between the secondary distribution in direct current and in alternating current. From this comparison it is proposed a microgrid architecture with 180V direct current bus consisting of a photovoltaic array and a battery bank that should maintain the power supply to a load fed in direct current. The work also presents the methodologies of choice, design, sizing and control of the static converters that make up the system and a proposal to control the flow of power between the renewable source, batteries, main grid and load. The operation of the microgrid is simulated through the PSCAD simulator and its performance is evaluated from the simulation results on two distinct points of operation: grid connected mode and isolated mode. When operating in grid connected mode, the main grid must absorb surplus energy at times when photovoltaic generation surpasses the demand and the battery bank is already fully charged or provide the necessary energy to maintain the voltage at the load if the photovoltaic generation is insufficient. In this mode of operation, even if the battery can supply power to the load, the microgrid system will prioritize demanding power from the main electrical grid, leaving the battery bank to be used in isolated operations. In isolated mode, the system power is totally dependent on photovoltaic generation and the battery bank, which must ensure continuity of energy to the load. Finally, the simulation results are presented in a transient regime after the interconnection of all the stages considering different operating scenarios.