A Novel Voltage Unbalance Indicator

Marcos Diego de Castro e Silva¹; Victor do Prado Brasil¹; Anésio de Leles Ferreira Filho¹

¹ Universidade de Brasília

Resumo

The main objective of this paper is to present a novel voltage unbalance indicator. The proposal separates the unbalance from the under or over voltage phenomenon. Additionally, only one threshold needs to be defined for regulation purposes, instead of multiple limits (as it is usual in more sophisticated indicators). Thus, it can be computed and applied in real world situations. Initially, line-to-line and phase- to-neutral voltages are analyzed regarding the variation of their symmetrical components. As a result, a novel factor is proposed and validated with experimental results. For this purpose, a three-phase squirrel cage induction motor, which is the industrial major load, is employed. Based on this study, it is possible to identify: i) a new voltage unbalance factor that is able to reduce uncertainties associated to this quantification process; and ii) whether line or phase voltages should be employed.

Palavras-chave: Voltage unbalance; symmetrical components; three-phase induction motor; temperature