Dynamic voltage regulator with solid state switched tap changer

Abstract

This paper describes a new dynamic voltage regulator (DVR) with the solid-state switched tap changer. Conventional solid-state switched tap changer was modified to minimize the total cost and the harmonic contents in the injected voltage. Proposed DVR was designed to compensate the typical power disturbance such as the voltage sag up to 50% level. It is composed of a parallel transformer, a series transformer, gate turned-off AC switches and bypass switches. Since the proposed DVR does not need any kind of energy storage devices such as capacitor or battery, we can minimize maintenance problems and maximize reliability compared to the conventional DVR, which is composed of voltage sourced inverter and energy storage capacitor. In the proposed DVR, the bypass switch shorts the secondary winding of the series transformer during the normal condition. On the other hand, AC switches are controlled to compensate the voltage sag during the voltage disturbance. Parallel transformer provides only two tap voltage levels to minimize the number of switching devices. The basic operation of the proposed DVR was explained, and new output voltage control algorithm was discussed. The proposed DVR was verified through the computer simulation.