Power Electronic On-Load Tap Changer for HVDC Converter Transformer

Abstract: High voltage DC transmission is gaining more and more importance due to various advantages over high voltage AC transmission. High voltage DC converter transformer is the main component which is used in HVDC transmission. Tap changer is an essential part of any power transformer for obtaining various turns ratios to get different voltage levels. Conventional mechanical tap changers are commonly employed for this purpose. Mechanical tap changers require continuous maintenance when tap changers require frequent operation. The tap changers in high voltage DC converter transformer is such an application where frequent operation of tap changer is needed. In this work a novel power electronic tap changer is proposed for arc less switching and reduced maintenance even under frequent operations. The basic working of the power electronic tap changer, different topologies and certain design parameters of power electronic tap changer for HVDC converter transformer are evaluated and tested using simulation software and a low voltage working prototype.

Keywords: HVDC, Converter Transformer, Tap changer, HVDC Transmission, Tap selector switch