Impactos de cargas motrizes na qualidade de energia e eficiência energética em uma nanorrede de distribuição em corrente contínua

Abstract

This work presents an experimental study involving the impacts of rotative loads on electrical energy quality and energy efficiency in a Direct Current Distribution Nanogrid (DCDN) idealized and implemented by the Grupo de Estudos e Desenvolvimento de Alternativas Energéticas (GEDAE) in Ilha das Onças, a community on the banks of the Piramanha River, Barcarena-Pará. Therefore, two types of rotative loads were selected for this work: DC motor pumps, directly connected to the DCDN, and AC models, supplied through inverters; and refrigeration equipment: refrigerator and freezer, both with the same compressor model and operating on direct current. The work presents the technical characteristics of the DCDN, as well as the instrumentation used for measurement and data acquisition involving electrical parameters of the grid and monitored loads. The energy quality events addressed relate especially to the presence of ripples with the injection of AC current along the DCDN in the steady-state operation regime of the rotative loads and inrush current during the activation of the motor pumps. Regarding short-duration events, focus is given to voltage sag during the activation of refrigeration, as there is a peak of demand of high magnitude, reaching more than 28 times the effective nominal current, or rms value, for one of the loads. Concerning energy efficiency, a comparative study is conducted involving the current operational scenario of the nanogrid with the use of mixed DC and AC loads and other technically feasible but not implemented scenarios, in order to highlight the benefits of the current configuration for energy supply to families in the area. Finally, cost avoidance estimates and emission reductions are also addressed, considering the use of gasoline motor pumps before the implementation of the DCDN, through the presentation of data and information obtained from one of the households presented in the work.