Optimal voltage regulation of power systems under transient conditions

Voltage variation in a power system may take place owing to slow changes of the load as well as to some transient disturbances in the system. In this paper, a method of optimal voltage regulation for fast changing loads is suggested. A single-machine infinite bus system along with a load is considered. The system model is formulated using Park's equations. Formulation of an appropriate cost function for the optimization problem is discussed. The proposed control is a variable capacitor at the load bus. Numerical results are presented for two different loads varying with time. The results indicate that a considerable improvement in voltage regulation can be obtained by optimally varying the control capacitor. The method can be used for any type of transient disturbance in the system. The method for extension to a multimachine system is outlined.