Análise de compensação de reativos para melhoria da eficiência energética em um empreendimento do setor comercial

Abstract

This study investigates the electrical installation of a commercial consumer unit in the financial sector, highlighting energy efficiency from the construction phase through the completion of the project. Indicators are presented to support the selection of construction alternatives aimed at improving power quality, energy efficiency, and economic performance. In a competitive and sustainability-oriented environment, efficient energy management is essential; however, many projects underestimate the impact of a low power factor (PF). An analysis of utility bills from a 15-month case study identified an increase in reactive energy consumption even with only a limited number of loads connected during the construction phase. Inductive equipment, such as transformers, motors and air-conditioning systems, requires a significant amount of reactive power, reducing the installation's power factor. In parallel, the aggregation of nonlinear loads introduces harmonic distortion into the electrical network, compromising power quality. The main objective of this study is to evaluate the impacts of a low power factor and propose technically and economically feasible solutions. Three alternatives were considered: (i) an automatic capacitor bank; (ii) photovoltaic inverters with reactive power compensation (Q Night) and renewable energy sources; and (iii) rational energy-use strategies for the post-construction phase. The results indicate the potential for reducing tariff penalties and optimizing the use of active power, resulting in improvements in overall energy efficiency. The analyzed consumer unit is classified as Commercial, subclass "Other Services and Activities," under the Green Time-of-Use Tariff (THS Green – A4), supplied by Cemig at 13.8 kV, with a secondary voltage of 380/220 V, located in Uberlândia, Minas Gerais, Brazil, where construction activities were carried out between 2018 and 2020.