Multi-pulse HVDC system using auxiliary circuit

2 1 The present invention relates to a multi-pulse HVDC system which is capable of minimizing the number of thyristors by providing a thyristor auxiliary circuit in a conventional 12-pulse thyristor HVDC(High Voltage Direct Current), not using an additional stack of a thyristor and which is implemented based on an auxiliary circuit having a multi-pulse thyristor HVDC system like 24-pulse/36-pulse/48-pulse converters. The multi-pulse HVDC system is characterized in that an upper side thyristor converter and a lower side thyristor converter are installed in a Δ-Δ-Y transformer , and two current smoothing reactor and a direct voltage dividing condenser are installed between the upper side thyristor converter and the lower side thyristor converter , and two thyristors : Tand Tare connected to one double winding transformer