Abstract: A leakage current measurement apparatus for measuring leakage currents is disclosed. The leakage current measurement apparatus automatically selects one of non-inductive shunt resistors of 10?, 100?, and 1000? and measures leakage currents of an outdoor isolation material for an ultra-high voltage. Additionally, the leakage current measurement apparatus is capable of measuring a relatively wide range of leakage currents with a relatively high precision, even at a remote location, as a measurement range is automatically adjusted within measurement ranges preset by a user when leakage currents of an outdoor isolation material change, and being protected against a surge possibly generated by an ultra-high voltage. Also, it can remotely measure in real-time leakage currents of an outdoor isolation material installed at a remote location over Ethernet.

Abstract: 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 12 and a lower side thyristor converter 13 are installed in a ?-?-Y transformer 11, and two current smoothing reactor 39 and a direct voltage dividing condenser 38 are installed between the upper side thyristor converter 12 and the lower side thyristor converter 13, and two thyristors 32, 33: T2 and T1 are connected to one double winding transformer 31.

Abstract: 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 12 and a lower side thyristor converter 13 are installed in a &Dgr;-&Dgr;-Y transformer 11, and two current smoothing reactor 39 and a direct voltage dividing condenser 38 are installed between the upper side thyristor converter 12 and the lower side thyristor converter 13, and two thyristors 32, 33: T2 and T1 are connected to one double winding transformer 31.