Estudo de proteção e seletividade de uma subestação de média tensão com unidade geradora e consumidora

Abstract

This work presents a case study of a protection system for a metallurgical company located in Alto Uruguay, which will be responsible for ensuring the safety of the site, installed equipment and employees. It is installed inside the medium voltage cubicle that is present in the 13,8 kV substation. The substation has 2 transformers, one of 1 MVA and one of 300 kVA. The medium voltage cubicle is powered by energy from the current CPFL concessionaire and by energy from solar generation. The protection system has 3 units, generating unit, consumer unit and general unit. In the generating or solar unit, the necessary protections were defined through current standards for parallelism with the network, with the short-circuit data provided by the concessionaire, a methodology was applied to determine the parameterization of the protection functions that the URP6000 relay will be responsible for carrying out. The same methodology was applied to the other units, however, a different relay was used due to the simplicity of the units. Furthermore, a calculation report was carried out to size the current transformers responsible for measuring currents present in the cubicle and also the potential transformers responsible for measuring voltages and supplying protection components. Finally, it presents the selectivity coordinates between the protection units and a selection of components for the protection system. The project integrated a substation with 1300 kVA photovoltaic generation, focusing on cost reduction and revenue generation. Protection studies were carried out and devices were configured to ensure the safety and efficiency of the system, serving as a basis for future implementations.