Power system voltage regulation based on voltage feedback using a dynamic capacitor

Abstract

Over twenty-four hours of operation of a power system there is a wide variation in the demand, resulting in voltage fluctuation. This fluctuation may be large enough to lead to inefficient and unreliable operation of industrial plants. The fluctuation can be overcome by proper choice of controls (capacitors) located at suitable points on the power networks. To maintain the voltages within tight admissible limits, it is necessary to obtain a complete dynamic model of the generation-transmission system. In this paper, the dynamic model of a power system consisting of a synchronous generator, a transmission line containing four buses, and control capacitors placed at the buses is considered. Two types of control (capacitor) are used to regulate the voltages, (i) a synchronous capacitor and (ii) a static capacitor. A mathematical model of the controls is also presented. In this study, three separate cases of loads at the buses are simulated in the dynamic system. In all the cases the proposed controls are used to regulate the system voltages. The results indicate that, with the variation of loads, the desired voltage regulation can be achieved by proper choice of capacitor controls as functions of time.