Estudos dos impactos da inserção de fontes renováveis de geração distribuída na seletividade e coordenação da proteção de sistemas elétricos

Abstract

The presence of renewable energy sources connected to the Brazilian’s electric system has been growing exponentially given the need to diversify the energy matrix and the high demand for energy in large consumer centres and rural locations. In the context of the worldwide concern with the environment and sustainable development, the strong incentive for the use of renewable energy has resulted in high investments for technological development that makes this generation increasingly efficient, profitable and attractive in the market, among many other advantages provided by the use of these sources. Given this scenario, the concept of distributed generation has been spread out and, currently, the increase of its installed capacity throughout the country has caused considerable changes in the characteristics of the Brazilian’s electric systems. Such changes make it necessary to evaluate the interference caused by the insertion of DG sources in the system’s operation in order to reduce impacts and guarantee the quality of the energy supplied to the consumers. In this sense, the objective of this work is to evaluate how the insertion of DG affects the correct performance of the protection systems, especially the coordination and selectivity of the distribution networks with respect to short-circuit currents. A case study will be carried out with the evaluation of scenarios that consider different connection points of a GD source in the distribution network, which may be wind or photovoltaic, injecting different power levels to reflect the intermittence of these systems. For each scenario the impacts on the network will be verified, initially with the protections adjusted in a selective and coordinated manner without the inclusion of GD, in order to identify maximum powers and current injection points can be applied by a new power source of GD without interfering in the operating protection system. Thus, it is intended to ensure that system coordination and selectivity are maintained after the insertion of the new distributed generation source into the distribution network, ensuring that faulty circuits are identified in the shortest possible time and removed from service without interfering with regions not subjected to these failures, allowing greater system availability.