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 return path between a first HVDC station and a second HVDC station. A first electrode is connected to the first station and a second electrode is connected to the second station. The return path includes a first part including a first low resistive zone through the crust of the earth in which the first electrode is embedded. A second part includes the earth mantle. A third part includes a second low resistive zone through the crust of the earth in which the second electrode is embedded.

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.

Abstract: A land electrode for a high voltage direct current transmission system including a converter station with a grounding point. The land electrode is connected to the grounding point and includes a plurality of electrode sections. Each electrode section includes at least one electrode element.

Abstract: A disconnector for interrupting a current path on a voltage of at least 100 kV with respect to earth. Two groups of elongated post-like support insulators are adapted to rest on the ground and support an end of a conductor each on a high level above the ground. A disconnector arm is connected to one or both of the conductor ends and is moveable for connecting and disconnecting these conductor ends. At least the external parts of the support insulators are made of a hydrophobic rubber composite insulating material.

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: An arrangement with a conductor (15) intended to be on a high potential and a part (12) connected to ground and separated therefrom by at least a voltage receiving air gap (16, 17), comprising an insulating envelope (18) surrounding said conductor and at least a first member (9) of electrical insulating material arranged to screen off said ground part from said conductor. Said air gap is dimensioned to get such a high electrical field strength by possible sudden, strong voltage raises of said conductor, that air molecules in said air gap will be ionized. Said insulating envelope (18) and the insulating member (9) have surfaces arranged to receive electrical charges generated through said ionizing for creating a voltage over their thicknesses and decreasing the voltage drop in the air gap between the conductor (15) and the ground part (12).

Abstract: An HVDC transmission has two converters (SR1, SR2). Each converter is connected between an alternating-voltage network (N1, N2) and a d.c. link (L1, L2) common to the converters. At least one converter is connected to its alternating-voltage network without the use of any full transformer, for example directly, or via an inductor or an autotransformer, or via series capacitors. The transmission has a mutual inductor (IB) which is arranged on the d.c. side of the converter and which has two windings (IB1, IB2) which are each connected to a respective one of the d.c. supply lines of the converter and are magnetically coupled to each other, the inductor being designed and connected so as to exhibit a high impedance to ground mode currents.

Abstract: A valve stack for high voltages includes a number of electrically interconnected valve modules, some of which are disposed one above the other. To prevent a large fire in a valve module from spreading upwards to valve modules positioned above it, fire screens are arranged between valve modules located one above the other.

Abstract: A power semiconductor valve device including an enclosure for semiconductor components and a hollow insulating body to supply power to the semiconductor components from a remote location, in which the hollow insulating body is formed from a non-ceramic material and includes concentrically mounted tubes spaced from each other to provide an annular gap between them.