Abstract: A high voltage bushing including an electrical conductor configured to be electrically connected to a high voltage device and configured to be connected to an external fluid cooling system, and an insulating body surrounding the electrical conductor. A method includes cooling the high voltage bushing by connecting the electrical conductor to an external fluid cooling system.

Abstract: A device for breaking DC currents exceeding 2500 A has a resonance circuit connected in parallel with an interrupter and a surge arrester connected in parallel with the resonance circuit. The resonance circuit has a series connection of a capacitor and an inductance. The relationship of the capacitance in ?F to the inductance in ?H of the resonance circuit is ?1.

Abstract: A HVDC transmission system including at one end of a bipolar HVDC transmission line a converter station for connecting the transmission line to an AC system. The station has two converters and a DC neutral arrangement in common to the converters. The DC neutral arrangement has a separate electrode line connecting member connecting to electrode lines. The electrode lines are dimensioned to be able to at monopolar operation of the converter station transmit substantially full current to an electrode station through the remaining one or ones of the electrode lines at disconnection of an arbitrary of the electrode lines.