SOLAR PHOTOVOLTAIC-BASED DC MICROGRID TESTING UNDER REAL-WORLD OPERATING CONDITIONS

Abstract

The concept of direct current distribution minigrids has been gaining ground in academia and industry regarding the development of distribution grid applications with high penetration of distributed energy sources and storage systems, as DC distribution system facilitates the grid's integration of sources and loads. This work presents the development of a direct current distribution microgrid installed in the laboratory of the Grupo de Estudos e Desenvolvimento de Alternativas Energéticas, of the Universidade Federal do Pará. The developed grid is composed of three combined photovoltaic generation and battery storage systems, utiling commercial charge controllers as interfaces onto the, and three load banks. These are distributed over the 200 m grid in a ring topology, with a nominal 24 VDC bus. Measurements are made at strategic points on the grid to access the system behavior under specific operating conditions, being normal or under fault conditions. The results attest the microgrid's ability to reliably supply the loads, as long as it respects the limitations of the implemented power generation and storage capacities. In addition, it was found that the characteristics related to the topology of the commercial charge controller benefits the power quality for the developed grid size and topology.