Estudo de proteção e seletividade aplicado à conexão de um sistema geração distribuída em uma subestação de média tensão

Abstract

This work presents a protection and selectivity study applied to the connection of a photovoltaic power plant of approximately 1.4 MWp to a medium-voltage substation. The objective was to evaluate and validate the coordination between the consumer unit protection and the utility protection, in accordance with the criteria established by Energisa-MS standards NDU-002 and NDU-015. The methodology was based on a case study, including system data collection, per-unit electrical modeling, calculation of symmetrical and asymmetrical short-circuit currents, determination of ANSI and NANSI points of the transformers, and definition of the settings for phase and neutral overcurrent protection functions. The results, presented through coordination curves, demonstrate that the adopted settings ensure protection selectivity, respect the thermal limits of the equipment, and guarantee the reliability and safety of substation operation. It is concluded that the applied methodology meets the regulatory requirements and can be used as a reference for similar studies in medium-voltage distributed generation systems.