ANÁLISE DE QUALIDADE DE ENERGIA EM PARTIDA DE MOTORES ELÉTRICOS DE INDUÇÃO TRIFÁSICOS: comparação dos métodos de partidas

Abstract

This academic work will address a study regarding the power quality in starting three-phase induction motors, making a comparison of starting methods. The main methods that will be studied and compared are star-delta starting, electronic starting using soft-starter and starting with frequency inverter. These studies are necessary because industries and electrical machines are in great growth and development in today's society, and the poor quality of electrical energy in the network may influence several economic aspects, thus, the main disturbances that will be studied and analyzed in this research are voltage variation, fluctuation, surge and unbalance, frequency variation, power factor, harmonic distortion and noise. The objective of this research will be to carry out the analysis of power quality at the time the electric motor starts, obtaining the disturbances of the three mentioned starting methods and thus pointing out which method(s) cause less disturbances in the electrical network. The analyzes were carried out in a feed industry, located in Três Corações - MG. Studies were carried out on 75hp pneumatic transport exhaust motors, with the Fluke model 435 analyzer being installed in the three starting methods. In the tests, significant values of disturbances were not obtained in the star-delta and soft-starter starters, obtaining values within the limits specified by Prodist in its module 8. However, in the frequency inverter starter, a high value of voltage harmonic distortions was obtained, and for the level of working voltage used, Prodist allows a maximum of 10%, and 34.5% was obtained. Therefore, after obtaining all the analysis and data, this research will present the final result, with the most viable method to be used, to obtain energy quality within the standards.