Formula for the effect of a static VAr compensator on synchronising torque coefficient

A static VAr compensator (SVC), constructed by a fixed capacitor (FC) and a thyristor controlled reactor (TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the power system voltage. The SVC is placed at the generator bus terminal, with the speed and voltage deviation as the feedback signals. In this paper, a formula has been developed showing the effect of SVC on synchronising torque coefficient, such that damping is improved and the system voltage is controlled. A simplified analysis of the effect of SVC on the stability of a machine connected to an infinite bus, as well as a simplified 21 bus real power system, is presented. Results from digital simulation show that the SVC can greatly enhance the damping of power system oscillations caused by disturbances. Also, the voltage profile of the generator is controlled by the SVC