Synthetic Test Circuit for Thyristor Valve in HVDC Converter with New High-Current Source

Synthetic test circuit (STC) for thyristor valve test consists of a low-voltage high-current source to provide the forward current during turn-on state and a low-current high-voltage source to provide the reverse and forward voltage during turn-off state. This paper proposes a new low-voltage high-current source for STC that has a six-pulse thyristor converter and a two-phase chopper with an auxiliary switch. The operation of STC with a new low-voltage high-current source was verified through theoretical analysis and computer simulations with PSCAD/EMTDC. Based on computer simulation results, a scaled hardware system for the proposed circuit was built and tested to confirm the feasibility of implementing a real-size STC.