Control and characteristics of a static VAr generator under single-line-to-ground faults

In recent years, static VAr generators (SVGs) have been developed for improving power factor and stabilizing transmission systems. The active/reactive power control based on the p-q theory or the d-axis/q-axis current control based on d-q transformation is applied to an SVG. This paper deals with a comparative study of the two control schemes under single-line-to-ground faults. With the focus on three-phase supply currents and the DC capacitor voltage of the SVG, the two schemes are compared by computer simulation under an unbalanced condition that a supply voltage sag is caused by a single-line-to-ground fault.