Desenvolvimento de software para análise de qualidade da energia em microrredes com fontes renováveis

Abstract

This thesis presents the development of a LabVIEW-based software for analyzing power quality in electrical distribution systems, focusing on grid-connected microgrids equipped with battery storage. The software processes voltage and current data collected from a commercial power quality analyzer and performs a comparative evaluation between the analyzer’s measurements and its own calculations, thus validating its accuracy. A key feature of the software is its ability to provide automatic diagnostics of power quality parameters — including power factor, total harmonic distortion, voltage imbalance, and frequency variations — in compliance with national and international standards (URSEA, IEC and IEEE). The studied microgrid comprised photovoltaic generation, a battery bank and varying loads. Extensive experimental tests were carried out: first, synthetic waveforms (both ideal and distorted sine waves) were used to verify the instrument’s oscilloscopic and spectral analysis functions; then, physical measurements were taken under balanced and unbalanced load conditions, as well as during dynamic load transitions of a three-phase induction motor driving a pump. The results demonstrated strong agreement between the software and the commercial analyzer, confirming the tool’s precision in capturing real disturbances. For instance, voltage and current waveforms matched closely (differences within rounding errors), and transient events (such as load switching) were correctly identified. These findings validate the software’s effectiveness in both analysis and automated diagnosis of power quality issues. In conclusion, the developed software provides an efficient and user-friendly solution for power quality monitoring in low- to high-power systems, supporting improved monitoring and control of modern microgrids with renewable sources.