Abstract:
The Thyristor-Controlled Phase Shifting Transformer (TCPST) holds significant prospects in the increasingly complex power grid flow control due to its reliable load regulation and cost-effectiveness. However, the semi-controlled characteristics of thyristors introduce the possibility of coil short-circuit-induced current surges during mode switching, restricting the widespread engineering application of TCPST. This paper first proposes a hybrid TCPST based on a novel matrix direct AC-AC conversion topology to address this issue. Then, an anti-surge driving strategy is introduced for mode switching based on the hybrid TCPST topology: a locking driving strategy that combines valve current direction and operating mode to address the current surge issues induced by coil short-circuit during mode switching. Additionally, an
RC buffer circuit is added within the valve assembly, and a power reference threshold is introduced in the driving strategy to mitigate the associated valve assembly momentary open-circuit voltage surge issues. Finally, simulations are conducted on a 220kV grid environment with the hybrid TCPST, confirming the effectiveness of the proposed anti-surge driving strategy.