This paper investigates the impacts of small-scale distributed energy resources (DERs) on fault currents and overcurrent protection (OCP) coordination in distribution feeders, considering the Brazilian regulatory framework. Changes in fault current levels and OCP coordination are analyzed by focusing on the relationships between DER location, output power, and OCP positioning. Simulations were conducted in Simulink/MATLAB using the IEEE 13-Node Distribution Test Feeder as a case study, considering various DER integration scenarios. The DER model adheres to the Brazilian standard NBR 16149:2013, which governs fault current injection and voltage ride-through behavior. The results indicate that DER integration can disrupt OCP coordination and significantly affect fault current levels, despite their relatively small current contributions during faults. In one scenario, OCP coordination was lost, while in others, coordination time intervals decreased. The findings show that DER location has a minimal influence on fault current changes, whereas output power plays a more critical role. Faults occurring farther from the substation cause greater current variation in installed relays, with deviations nearing ±10%. Additionally, reverse fault currents through relays are identified as a key concern for protection engineers.

Hydroelectric plants are responsible for generating about 85% of the electricity produced in Brazil. However, after a severe drought has affected the country in 2014 and 2015, the Brazilian energy matrix had a momentary change. It was necessary to dispatch thermal plants which were primarily used only to supplement power generation. Meanwhile, this type of generation plant significantly contributes to burning fossil fuels. Gas emission intensifies acid rain, global warming and is responsible for climate change, which ultimately deteriorates human health. There are many studies that correlate pollution escalation with increased hospital admissions due to respiratory and cardiovascular problems, raising the costs of public health spending. This study aims to establish a method to estimate economic advantages of solar distributed micro generation for homes concerning to the avoided amount spent by the government to mitigate negative effects, specifically pollution-related health problems, from the use of thermal plants. Finally, through a case study, this paper suggests some incentives that could be offered to citizens who had installed solar energy systems in their homes, once they would contribute to reduce public health costs.

Using distributed generation (DG) to replace the traditional way of generate electricity is gaining more notoriety in the world whether due environmental, political or economic reasons. The growth of this new way of generating electricity requires standards to guarantee the reliability and selectivity of network protection equipment, system stability and consumer safety. In 2008 and 2012, the Brazilian National Electric Energy Agency (ANEEL) published documents that establish project requirements, protection functions and conditions for energy compensatory system. Currently, each Brazilian power distribution company produces its own technical standards that theoretically should follow the national regulations. However, it is noted that some companies fail to prepare it, omitting required protection functions and/or establishing more restrictive requirements, which can lead to misinterpretations. Therefore, this article intends to analyze the distributed generation standards of the main Brazilian power distributors and identify the protections required by the companies, explaining their necessity, for connection of DG. A brief analysis is also made comparing the Brazilian standards with the international guidelines.