Assessment of voltage unbalance using complex voltage.

Firstly, this paper discusses the adverse effects of voltage unbalanced on the steady state performance of 3-Phase Induction Motor (3-0 IM). The characteristics of 3-Phase IM under the various conditions and degree of voltage unbalanced have been analyzed during its steady state condition. It is shown that the voltage unbalanced condition as well as degree of unbalanced produce the pulsation in torque and speed. Consequently, there is a reduction in the efficiency and increment in the copper loss of 3- 0 IM. Furthermore, the shortfalls of existing Power Quality (PQ) index, namely voltage unbalanced factor (VUF), used for the assessment of performance of 3- 0 IM under the voltage unbalanced condition, are highlighted. Finally, an index, namely Complex Voltage Sum (CVS) denoted by Vot, using symmetrical components of voltage, has been developed to overcome the shortfalls associated with VUE And it has been shown that Vot is sufficient to indicate both the degree and condition of voltage unbalanced. [ABSTRACT FROM AUTHOR]