Patent Description:
When electrically connecting a bushing with a transformer, typically a manhole in the transformer tank is needed for accessing and manually connecting an electrical contact at the proximal end of the busing within the transformer. Alternatively, a draw-rod system may be used for connecting an electrical contact at the distal end of the bushing, without the need for a manhole.

<CIT>, <CIT>, <CIT> and <CIT> disclose an electrical induction device comprising a housing and a contact arrangement in the housing of the electrical induction device for electrically contacting an electrical conductor.

It is an objective of the present invention to provide a way of connecting an electrical conductor, e.g. of a bushing, cable ending or surge arrester, with an electrical induction device, e.g. a transformer or a reactor, in a contact arrangement within a housing of the induction device without the need for a manhole in the housing for manually accessing the contact arrangement. The contact arrangement may be regarded as comprising a plug-in contact which may be connected automatically, without the need for an operator physically accessing and adjusting the contact arrangement.

According to an aspect of the present invention, there is provided an electrical induction device comprising a housing and a contact arrangement in the housing of the electrical induction device for electrically contacting an electrical conductor. The contact arrangement comprises a conductor tube, a receiver contact which is fastened to the conductor tube and configured to receive and electrically connect with the electrical conductor, and a resilient suspension arrangement fastened to the housing and connected to an outside of the conductor tube such that the receiver contact is resiliently movable in a plane which is parallel to a cross section of the conductor tube while being substantially immovable in an axial direction of the conductor tube.

According to another aspect of the present invention, there is provided an induction device arrangement comprising an embodiment of the electrical induction device of the present disclosure, and the electrical conductor, wherein the contact arrangement is electrically contacting the electrical conductor.

By means of the resilient suspension arrangement, the receiver contact is movable in the xy-plane such as to allow it to automatically adjust to the position of the electrical conductor as it is introduced in the contact arrangement. The increased tolerances thus provided for the position and/or inclination of the electrical conductor as it is introduced into the contact arrangement facilitates electrically (galvanically) connecting the electrical conductor with the conductor tube via the receiver contact of the contact arrangement without having to manually adjust the contact arrangement, e.g. via a manhole in the housing. The electrical conductor may more easily be connected by only manipulating it from the outside, not the inside, of the housing.

It is to be noted that any feature of any of the aspects may be applied to any other aspect, wherever appropriate. Likewise, any advantage of any of the aspects may apply to any of the other aspects. Other objectives, preferred features and advantages of the enclosed embodiments will be apparent from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

<FIG> illustrates an induction device arrangement <NUM> comprising an electrical induction device <NUM> and a conductor arrangement <NUM>.

The induction device <NUM> may e.g. be or comprise a transformer or a reactor, e.g. a high-voltage transformer. The induction device <NUM> comprises a housing <NUM>, e.g. a transformer tank or reactor tank, which may enclose conductor windings of a winding arrangement <NUM> of the induction device. The induction device <NUM> may be fluid-filled, the housing <NUM> being filled with an electrically insulating fluid <NUM>, e.g. a gas or liquid, typically a liquid such as a transformer oil or ester liquid. Through an opening in a top or side wall <NUM> of the housing <NUM>, an electrical conductor <NUM> may be galvanically connected to the induction device <NUM>, typically to any of the windings of the winding arrangement <NUM>, e.g. at a turret <NUM> of said wall <NUM>.

The conductor arrangement <NUM> comprises the electrical conductor <NUM> and may e.g. be or comprise a bushing, a cable ending or a surge arrester, e.g. a high-voltage bushing. Preferably, the conductor arrangement is sealed, e.g. by means of the contact arrangement <NUM>, such that the electrically insulating fluid <NUM> (if any) is not able to enter the conductor arrangement <NUM>, e.g. in or along the electrical conductor <NUM>. The electrical conductor may be in the form of e.g. a solid rod, a flexible wire or a tube, preferably a conductor tube.

The contact arrangement <NUM> is arranged within the housing <NUM>, typically fastened to or otherwise mounted to the housing. The conductor arrangement <NUM> is arranged for electrically (galvanically) connecting the electrical conductor <NUM> with the conductor tube <NUM> of the induction device <NUM> within the housing <NUM>, to form an electrical connection <NUM>.

<FIG> illustrates a contact arrangement <NUM> mounted to the housing <NUM>, e.g. in a turret <NUM> thereof. The housing <NUM> may e.g. form a tubular opening through a wall <NUM> of the housing in which opening the contact arrangement is mounted.

The contact arrangement <NUM> comprises a receiver contact <NUM>, e.g. comprising flexible fingers or springs, or the like, for pressing against the electrical conductor <NUM> when it is received in the receiver contact, forming a galvanic connection with the electrical conductor. The receiver contact <NUM> is fastened to the conductor tube <NUM>, e.g. to an end <NUM> of the conductor tube or on an inside <NUM> of the conductor tube at said end <NUM>. As an example, the receiver contact <NUM> may be or comprise a MULTILAM flexo ML-CUX™ from Stäubli.

In accordance with the present invention, the receiver contact <NUM> is movable in an xy-plane (a plane which is parallel to a cross section of the conductor tube <NUM>, e.g. a radial plane of the conductor tube <NUM>) while being substantially immovable in the z-direction which is the axial (longitudinal) direction of the conductor tube <NUM> (see also the schematic three dimensional cartesian coordinate system illustrated on the right side in <FIG>, illustrating x, y and z directions as well as an xy-plane). By the receiver contact <NUM> being movable in the xy-plane, the receiver contact is able to adjust its position in the xy-plane, without e.g. being pressed further into the housing <NUM> in the z-direction, to receive and connect with a proximal end <NUM> of the electrical conductor <NUM> as it is being inserted into the opening in the wall <NUM>. To further aid in the adjustment of the receiver contact <NUM> position when receiving the electrical conductor, the receiver contact <NUM> and/or the end <NUM> of the conductor tube <NUM> may comprise a guiding surface, e.g. comprising chamfers or the like for guiding the proximal end <NUM> of the electrical conductor <NUM> into the receiver contact while exerting pressure to induce the movement of the receiver contact in the xy-plane. A corresponding guiding surface may be present on an outside of the proximal end <NUM> (<FIG>) of the electrical conductor, e.g. by the proximal end <NUM> being tapered or rounded. Since the receiver contact <NUM> fastened to the conductor tube <NUM>, it is implied that also said conductor tube <NUM> is movable in the xy-plane, at least at the end <NUM> of the conductor tube while other parts of the conductor tube may be fixed. It is noted that the conductor tube <NUM> may comprise a flexible portion to allow an end portion of the conductor tube, at the end <NUM> thereof, to be movable in the xy-plane, while another portion of the conductor tube is immovable (fixed).

The receiver contact <NUM> is movable by means of a resilient suspension arrangement <NUM> fastened to the housing <NUM> and connected to an outside <NUM> of the conductor tube <NUM> such that the receiver contact <NUM> is resiliently movable in the xy-plane. The resilient suspension arrangement <NUM> may comprise at least one spring which has spring action in an xy-plane but immovable in the z-direction. The spring may e.g. be formed by bent sheets of e.g. spring steel or the like. However, it may be preferable that the resilient suspension arrangement <NUM> is not conductive, insulating the conductor tube <NUM> from the housing <NUM>. The resilient suspension arrangement <NUM> is typically arranged outside of and around the conductor tube <NUM>, e.g. in a radial plane of the conductor tube such as along a circumference of the conductor tube. The resilient suspension arrangement <NUM> may be intermittently or continuously connected to the outside <NUM> of the conductor tube <NUM> along the circumference of the conductor tube. In some embodiments, the resilient suspension arrangement <NUM> may be connected to the outside of the conductor tube <NUM> via a spacer <NUM>, e.g. a ring encircling the outside <NUM> of the conductor tube in a radial plane (xy-plane) of the conductor tube.

By the resilient suspension arrangement <NUM> preventing the receiver contact <NUM> from moving in the axial (z) direction, the receiver contact <NUM> is typically also prevented from rotating about the x or y axis, i.e. the resilient suspension arrangement <NUM> takes up torque about the x and y axes. Also, the receiver contact <NUM>, as well as the conductor tube <NUM>, is typically by the resilient suspension arrangement <NUM> prevented from rotating about the axial (z) axis.

<FIG> illustrates an electrical connection <NUM> formed by the electrical conductor <NUM> having been received by the receiver contact <NUM> and electrically connected to the conductor tube <NUM> via said receiver contact. As mentioned above, a guiding surface may be present on an outside of the proximal end <NUM> of the electrical conductor <NUM>, e.g. by the proximal end <NUM> being tapered or rounded or otherwise exhibiting chamfers, which may exert pressure on the receiver contact <NUM> and/or the end <NUM> of the conductor tube <NUM> to induce the movement of the receiver contact in the xy-plane as the proximal end <NUM> of the electrical conductor <NUM> is received by the receiver contact <NUM>.

When the contact arrangement <NUM> is not contacting the electrical conductor <NUM>, the receiver contact <NUM> may be in a resting position (an unbiased position), while when the receiver contact is receiving the proximal end <NUM> of the electrical conductor <NUM>, the receiver contact <NUM> may be moved in the xy-plane to a biased position to accommodate and properly connect to the electrical conductor. In some embodiments, the receiver contact <NUM> may thus be resiliently movable a maximum distance from the resting position in the xy-plane to said biased position, wherein said maximum distance may be e.g. within a range of from <NUM> to <NUM> or <NUM>. The maximum distance typically depends on the design of the resilient suspension arrangement <NUM>.

Claim 1:
An electrical induction device (<NUM>) comprising:
a housing (<NUM>); and
a contact arrangement (<NUM>) in the housing (<NUM>) of the electrical induction device (<NUM>) for electrically contacting an electrical conductor (<NUM>), the contact arrangement comprising:
a conductor tube (<NUM>);
a receiver contact (<NUM>) which is fastened to the conductor tube (<NUM>) and configured to receive and electrically connect with the electrical conductor (<NUM>); and
a resilient suspension arrangement (<NUM>) fastened to the housing (<NUM>) and connected to an outside (<NUM>) of the conductor tube (<NUM>) such that the receiver contact (<NUM>) is resiliently movable in a plane (xy) which is parallel to a cross section of the conductor tube while being substantially immovable in an axial direction (z) of the conductor tube.