Abstract: An arrangement for changing current return path in a bipole direct current power transmission system includes a converter station having an active and a passive converter connected in series between an active and a passive pole line via a first neutral bus, a metallic return transfer switch in an electrode line, a ground return transfer switch in a current redirecting path between the passive pole line and the neutral bus and a control unit which in case of change to the passive pole line for providing a return current path is configured to, upon control of power related to the active converter from steady-state to zero, close the ground return transfer switch and thereafter open the metallic return transfer switch, whereupon power related to the active converter may be controlled back to steady state.

Abstract: An arrangement for changing current return path in a bipole direct current power transmission system includes a converter station having an active and a passive converter connected in series between an active and a passive pole line via a first neutral bus, a metallic return transfer switch in an electrode line, a ground return transfer switch in a current redirecting path between the passive pole line and the neutral bus and a control unit which in case of change to the passive pole line for providing a return current path is configured to, upon control of power related to the active converter from steady-state to zero, close the ground return transfer switch and thereafter open the metallic return transfer switch, whereupon power related to the active converter may be controlled back to steady state.

Abstract: A power capacitor including at least one capacitor element enclosed in a container, wherein the container is of a material which substantially includes a first polymer material. Further, the container is cylindrical and provided in its surface with creepage distance extending protrusions of a second polymer material. The protrusions are formed with respect to their thickness and radial length so as to cool the capacitor. In a method for manufacturing such a power capacitor, a substantially cylindrical container is made of a material which substantially includes a first polymer material. The container is provided on its envelope surface with creepage distance-extending protrusions of a second polymer material and the capacitor elements are encapsulated in the container.

Abstract: A power capacitor for high voltage and including at least one capacitor element that has improved electrical properties and that allows simple manufacture. Each capacitor element has a substantially circular-cylindrical shape. The inside of the container has a corresponding shape to closely surround each capacitor element. In addition, each capacitor element is oriented with the axial direction coinciding with the axial direction of the container. A capacitor bank includes a plurality of the power capacitors, and uses of one or more of the invented power capacitors can be used as a component in electrical installations.

Abstract: A capacitor element (20) for a power capacitor with a dielectric film layer (3) and an electrode layet arranged on each flat side of the film layer, which electrode layers are divided into at least three metallized areas (4, 9, 10), separate from each other, in order to form an inner series connection arranged to conduct a load current, of which thee areas at least one is divided into segments (5) separated by non-metallized sections (6), and at least one bridge (7) arranged to electrically connect two of the segments together. In accordance with the invention the bridge is so arranged that, in the area divided into segments, the load current appears substantially only in the segments. The invention also relates to a power capacitor with such a capacitor element and also a metallized tape for such a power capacitor.

Abstract: The present invention relates to a power capacitor for high voltage and comprises at least one capacitor element (2a-2d). The object is to achieve a capacitor with improved electrical properties and which allows simple manufacture. According to the invention, each capacitor (2a-2d) has a substantially circular-cylindrical shape. The inside of the container (1) has a corresponding shape so as to closely surround each capacitor element (2a-2d). In addition, each capacitor element (2a-2d) is oriented with the axial direction coinciding with the axial direction of the container. The invention also relates to a capacitor bank (12) comprising a plurality of power capacitors of the invented kind, and to uses of one or more of the invented power capacitors as a component in electrical installations.

Abstract: A capacitor element (20) for a power capacitor with a dielectric film layer (3) and an electrode layer arranged on each flat side of the film layer, which electrode layers are divided into at least three metallized areas (4, 9, 10), separated from each other, in order to form an inner series connection arranged to conduct a load current, of which three areas at least one is divided into segments (5) separated by non-metallized sections (6), and at least one bridge (7) arranged to electrically connect two of the segments together. In accordance with the invention the bridge is so arranged that, in the area divided into segments, the load current appears substantially only in the segments. The invention also relates to a power capacitor with such a capacitor element and also a metallized tape for such a power capacitor.

Abstract: A capacitor electrode includes a film base member having connection means located thereon so that the capacitor electrode may be connected to an external component, and a segmented metallized layer connected to the connection means, the metallized layer being made of metallized segments interconnected by current gates. The segmented,metallized layer has a thickness which varies or differs continuously along a length thereof, and the current gates have a width which increases as the thickness of the segmented metallized layer decreases.

Abstract: A tubular core (6) for a controllable inductor with a main winding (1) surrounding the core and a control winding (7) passing substantially axially through the core. The core (6) is capable of receiving a magnetic flux from the main winding (1) running substantially axially therethrough and having a plurality of core rings (8) stacked co-axially on top of each other and connected to a rigid unit. The core rings (8) are connected to each other forming a walled construction. The core (6) also has an inner envelope (18) with an outer cross-section that is substantially equal to the inner cross-section of the core ring walled construction. The walled construction has joints (16) between the core rings (8) in an axial direction which are overlapped by a part of the envelope (18).

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: A controllable inductor including a tubular core, a main winding (1) surrounding the core, a control winding running substantially axially to the core and an element (3) surrounding the core and arranged to support the main winding wound outside thereof in radial layers. The element includes means arranged to provide channels (19) partly defined by the radially inner turn of the main winding. Said channels are communicating with spacings between said layers (2). A member is arranged to generate a flow of air in the channels and through the spacings of the layers for cooling the main winding.

Abstract: A controllable inductor including at least one tubular core (10), a main winding (5) surrounding the core and a control winding (11) running substantially axially through said core and returning substantially axially outside thereof between said core and said main winding. The control winding is divided into a plurality of separate part control windings (12). The cross section of the part control windings is formed in a way that at least some adjacent part control windings inside the core are separated by means of a spacing (20, 26), which is at least partly defined by substantially parallel surfaces (16, 17) of these part control windings.

Abstract: A controllable inductor comprises at least a tubular core (13) a main winding (5) surrounding the core, a control winding (13) passing substantially axially through the core, a ground part (15) arranged inside the main winding and an element surrounding the core and adapted to carry the main winding wound outside thereof at a distance to the ground part while creating a voltage taking air gap between the main winding and this part. The main winding has a first end (10) thereof on high potential and the potential falls towards the second opposite end (11). The element carries the main winding at the first end (10) at a larger radial distance to the ground part than at the second end.

Abstract: Filter equipment is adapted for connection to an ac power network (N) for damping of current harmonics originating from an installation (TR, SR1, SR2), connected to the network, for power transmission by means of high-voltage direct current. The equipment has a three-phase filter set (F) with three filter branches which are each normally connected to a separate phase of the network via first switching members (BO). A spare filter branch (FR) is arranged as a stand-by for the three filter branches of the filter set (F) and is adapted for connection to an optional phase of the network by means of second switching members (BR).

Abstract: A series-compensated converter station in an installation for transmission of high-voltage direct current is connected to an alternating-voltage network (N) with three phases (A, B, C, respectively). The converter station comprises at least two direct-voltage series-connected six-pulse converter bridges (SR1, SR2, respectively), a three-phase transformer coupling with two secondary windings (SW1, SW2, respectively), and a star-connected primary winding (PW) with a neutral point (NP) connected to ground as well as a series capacitor unit (CN) for each one of the three phases. Each one of the converter bridges is connected to a respective secondary winding and the primary winding is connected to the alternating-voltage network via the series-capacitor units. The transformer coupling exhibits a high impedance to zero-sequence currents through the primary winding of the transformer coupling.