Abstract: A plant for transmitting electric power comprises at least one VSC-converter (1). It comprises also at least one DC/DC-converter (33, 34) having two current valves connected in series and an inductance connected to a midpoint therebetween. The DC/DC-converter is through said inductance connected to a first of the poles of the direct voltage side of the converter and through a first output terminal connected to one of the current valves to the second of the poles so as to obtain an unbalanced step-up-transformation of the direct voltage between the two poles while obtaining a potential having a higher value on the second output terminal (27) of the DC/DC-converter connected to the second current valve than on said first output terminal (28).

Abstract: A plant for transmitting electric power is provided. The plant has a direct voltage network connected to at least one alternating voltage network through a station. The station transmits electric power between the direct voltage network and the alternative voltage network and has at least one converter for converting direct voltage to alternating voltage and for converting alternating voltage to direct voltage. The plant comprises a DC/DC converter connected between the poles of the direct voltage network. The DC/DC converter is adapted to create a higher voltage between the poles on the station remote side of the DC/DC converter than on the station near side.

Abstract: A plant for transmitting electric power comprises a direct voltage network for High Voltage Direct Current (HVDC) and at least one alternating voltage network connected thereto through a first station. The station transmits electric power between the direct voltage network and the alternating voltage network and comprises at least one VSC converter. The VSC converter converts direct voltage into alternating voltage and, conversely, alternating voltage to direct voltage. The alternating voltage network is a weak alternating voltage network, or a network without any generation of its own, and a large part of a load connected to the alternating voltage network consists of one or more electric motors.

Abstract: A breech mechanism for large caliber artillery pieces is characterized by a specifically designed sealing function in the form of an intermediate layer between a main portion of the breech mechanism and a seating portion displaceable in relation thereto by the gas pressure in the gun. The seating portion, on being displaced towards the breech, compresses the intermediate layer disposed therebetween and consisting of an elastically deformable refractory material which, on its deformation, is urged into tight abutment against the rear portion of the gun barrel about the loading space of the gun along a gap between the seating portion and the main portion of the breech mechanism.

Abstract: An improved gun barrel is disclosed in which the breech chamber has a length (B) and diameter (D.sub.2) which are chosen relative to the axial spacing (a) between a forward guiding ring (8) and a rearward driving band (6) of the ammunition unit to be fired from the barrel and relative to the diameters (d.sub.1 and d.sub.2) of the guiding ring and driving band, so that the longitudinal axis of the ammunition unit and the bore of the barrel are substantially aligned before the forward guiding ring enters the rifled portion of the bore.

Abstract: A high voltage direct current transmission includes a rectifier station and an inverter station connected by a DC line. The rectifier station has uncontrolled valves and an arrangement enabling current control to be effective at over-current conditions for controlling the alternating voltage connected to the valves. There are first and second control circuits, the first of which is controlled in dependence on the line voltage and the second in dependence on the line current. A circuit for selecting either the first or the second control circuit is provided between the control circuits and the voltage control arrangement. The valves of the rectifier station may be arranged in two six-pulse groups mutually offset in phase, so reactively connected that they have the commutating reactance partly in common.