Solid-State Tap Changers: New Configurations and Applications

Voltage regulation at the subtransmission and distribution levels strongly relies on the use of transformer tap changers, implemented these days with sophisticated yet fragile electromechanical mechanisms. The possibility of replacing mechanically operated switches by electronic devices has been the subject of much interest in the last few years. In this paper, a review of existing solid-state implementations is first made. Then, several alternative topologies are proposed and compared with those considered the best ones in terms of number of switches, number of auxiliary windings, number of switches in series and maximum blocking voltage. Finally, the application of the proposed schemes to distribution transformers, both at the primary and secondary levels, is addressed.