WO2012025571A2

WO2012025571A2 - Cable fitting comprising a field-control element and method of producing a cable fitting

Info

Publication number: WO2012025571A2
Application number: PCT/EP2011/064576
Authority: WO
Inventors: Richard Graf; David Pearce
Original assignee: Tyco Electronics Raychem Gmbh; Tyco Electronics Uk Ltd
Priority date: 2010-08-25
Filing date: 2011-08-24
Publication date: 2012-03-01
Also published as: DE102010039750A1; WO2012025571A3; DE102010039750B4

Abstract

The present invention relates to a cable fitting (100, 101, 02, 200, 300, 301, 400, 401, 402) for mounting to a cable (140), comprising a field-control element (110, 210, 310, 410) of an electrically conductive material. The field-control element is a partly everted tubular component (110, 210, 310, 410) comprising a curved section (111, 211, 311, 411, 412) being formed by the everting. The invention further relates to a method for producing such a cable fitting as well as to a field-control element for a cable fitting.

Description

Cable fitting comprising a field-control element and method of producing a cable fitting

The present invention relates to a cable fitting for mounting to a cable, the cable fitting comprising a field-control element of an electrically conductive material. The present invention further relates to a method of producing such a cable fitting as well as to a field-control element for a cable fitting .

Power cables having an operating voltage of 6 kV or above typically comprise inner and outer conductive layers in the cable insulation for field equalization. In order to connect such cables with other cables or devices, individual elements of the cables are in the area of the cable ends gradually exposed or cut back, respectively, and enveloping devices or connecting devices known as cable fittings such as e.g. cable terminations and cable joints are arranged at the cable ends. The existence of a cut-back end of an outer conductive layer, also known as cut-back edge or screen edge, however, leads to an increase of the electric field at this position in the operation of the respective cable. In order to guarantee a safe operation and in particular to make sure that the increase in the electric field does not lead to discharges, breakdowns or flashovers, the electric field is reduced by suitable means and measures which is known as field control. In this respect, known cable fittings usually comprise corresponding field-control elements or field-control bodies.

A typical means is what is known as geometric field control. At this, a funnel-shaped electrically conductive element is positioned above the cut-back edge of a conductive layer of a cable in order to make the electric field distribution uniform. The funnel-shaped or curved geometry is e.g. based on what is known as the Rogowski profile or n-Borda profile hav- ing constantly-changing radiuses by which ideal field characteristics may be achieved. Apart from that, field-control bodies having simpler profiles with several fixed radiuses are also known that may e.g. be used with cables having me- dium operating voltages of up to 42 kV.

Funnel-shaped field-control bodies that may be composed of conductive silicone rubber are typically produced by means of an injection-molding process. However, injection molding brings about extensive further treatment (in particular de- flashing, scavenging) in order to form the desired curved shape. The production of such field-control elements or cable fittings, respectively, having such elements is therefore associated with comparably high costs.

Moreover, other kinds of field control such as refractive field control are known. At this, field-control tubes made of special materials having strictly limited material properties are applied that may e.g. by produced by means of extrusion. Cable fittings provided with field-control tubes are usually configured to be shrunk onto cables by the influence of temperature ("heat shrink") . Due to the special materials, the use of such field-control elements, however, is (also) associated with a complex and cost-intensive production.

It is the object of the present invention to provide an improved solution for a cable fitting comprising a field- control element that is in particular associated with a simpler production.

This object is solved by the features of the independent patent claims. Further advantageous embodiments of the invention are indicated in the dependent claims. According to the present invention there is proposed a cable fitting for mounting to a cable that comprises a field- control element of an electrically conductive material. The field-control element is a partly everted tubular component that comprises a curved section being formed by the everting.

According to the present invention there is further proposed a method of producing a cable fitting. The method comprises providing a tubular component of an electrically conductive material and partly everting the tubular component in order to form a field-control element comprising a curved section. In the inventive cable fitting it is taken advantage of the fact that also a simple curving or, respectively, a simple radius at the end of a field-control body may cause a reliable field control. Such a curvature may not only be produced by means of a shaping process such as an injection-molding process but also by simply everting a tubular component. The curved section formed by the everting that may effect field control and that may therefore also be referred to as "field- critical surface" here comes from an inner surface or, respectively, an internal side of the tubular component. This side or surface, respectively, of the component may be formed evenly in a simple manner. Therefore, producing the curvature intended for field control does not require any extensive further treatment. Moreover, cost-efficient materials or "standard materials", respectively, may be used for the tubu- lar component. Consequently, a simple and cost-efficient production of the field-control element and thus the cable fitting is made possible.

In a preferred embodiment, the tubular component is provided by carrying out an injection-molding process. At this, simple injection-molding tools and molds may be applied.

In an alternative preferred embodiment, it is provided that the tubular component is provided by carrying out an extru- sion process. This embodiment is associated with further cost savings . In a further preferred embodiment, a housing part of an insulating material is formed, wherein the field-control element is embedded in the housing part. The insulating material of the housing part may e.g. be a silicone material.

Forming the housing part of the insulating material is preferably carried out by means of an injection-molding process.

In a further preferred embodiment, the field-control element comprises an electrically conductive rubber material or an electrically conductive silicone material. In order to be electrically conductive, the respective material may e.g. be provided with conductive sooty particles. The cable fitting may in particular be a cable termination or a cable joint for medium-voltage cables. The partly-everted tubular component may provide for a reliable field control in particular for such cables that are operated at voltages between e.g. 6 kV and 42 kV.

In a further preferred embodiment, a shaping element is provided over that the tubular component is everted. The shaping element may e.g. comprise a closed circumferential shape (in particular a ring shape) . This embodiment allows for the pos- sibility to provide the curved section with a relatively large curvature or, respectively, a relatively large radius of curvature which may in particular be considered with regard to applications with higher voltages of e.g. more than 24 kV in order to achieve a reliable field control. A larger radius of curvature may also be implemented by means of a larger wall thickness of the tubular component as the case may be. However, apart from a disproportionate high material usage this approach may also result in the everting being rendered more difficult or even being prevented. In contrast thereto, the tubular component may be configured with comparably thin walls due to the use of the shaping element by which material and thus costs may be saved. Furthermore, it is possible to implement the curved section with another outline than a simple radius, wherein this outline may be predetermined by the corresponding geometry of the shaping element in a simple manner. At this, the shaping element may comprise any arbitrary cross-section shapes that may e.g. be oval, round or drop-shaped.

In a further preferred embodiment, the tubular component is partly rolled-up in order to provide the curved section.

Rolling-up the tubular component which equates with "continuously" everting the same also allows for the possibility of providing a relatively large radius of curvature by means of a comparably thin-walled tubular component. With regard to rolling-up the tubular component, it may also be considered to use an additional shaping element. At this, it is provided that the tubular component is rolled-up over the shaping element. In a further preferred embodiment, the tubular component comprises two curved sections being formed by everting the tubular component. Furthermore, respective ends of the tubular component are connected to each other. In this embodiment, the tubular component comprises a continuous closed shape which makes it possible to move the tubular component applicable for field control to a desired position (in particular a screen edge) by simply rolling it on a device such as in particular a cable. Conventionally, elastic field-control elements are pushed-on ("push-on technique"), or are provided on a supporting body in a pre-expanded manner and are being guided down from the supporting body on a cable during installation ("cold-shrinking technique") . However, during the pushing-on, relatively high pushing forces may occur. The cold-shrinking technique, on the contrary, is associated with a limited storage time since the material is stored in a stretched manner ("tension set") . Such disadvantages may be prevented in the roll-able field-control element. The roll- able field-control element may e.g. be used in an oil-filled cable fitting in that a corresponding housing inside of that the field-control element is also included is filled-up with oil serving as electrical insulation.

In a further preferred embodiment, a lubricant and/or at least one shaping element is arranged in an internal space that is enclosed by the tubular component. The simple rolling of the tubular component on a device or cable, respectively, may be supported by the lubricant. Arranging a shaping element within the enclosed internal space provides the possibility of predetermining the shape of a curved section as well as of providing a relatively large curvature. In a further preferred embodiment, the tubular component is subjected to a bonding or, respectively, agglutination process. In this respect, it may in particular be considered to agglutinate adjacent layers of the (partly everted) tubular component and/or to agglutinate the tubular component with a shaping element. In this way, it is e.g. possible to secure the everted or rolled-up state of the tubular component.

According to the present invention there is further proposed a field-control element for a cable fitting. The field- control element comprises a partly everted tubular component comprising a curved section being formed by the everting. Hereby, a simple production of the field-control element is in particular made possible. This applies in a corresponding manner for a cable fitting comprising such a field-control element .

The above-described embodiments such as e.g. embedding the tubular component in an insulating material or silicone material, forming the curved section by everting the tubular com- ponent around or over a shaping element or, respectively, by rolling-up the tubular component, forming two curved sections by means of everting the tubular component and connecting the ends of the tubular component, agglutinating, etc. may also be considered for the above-mentioned field-control element. In a corresponding manner, the respective tubular component may comprise an elastic and electrically conductive material such as e.g. an electrically conductive rubber material or an electrically conductive silicone material.

Alternatively, there is the possibility that the tubular component is only partly electrically conductive and e.g. com- prises a basic body of an elastic insulating material (such as e.g. a rubber or silicone material), wherein the basic body is provided with an electrically conductive coating. Herein, the conductive coating, e.g. a conductive varnish based on silicone, may be arranged in the area of the curved section on a side of the tubular component that forms the component's internal side before everting the same. By means of such a coating, a reliable field control may also be effected . The embodiments as previously described and/or embodiments indicated in the dependent claims may - except for e.g. in cases of clear dependencies or inconsistent alternatives - be applied individually but also in any combination with each other .

The invention is in the following described in conjunction with the accompanying figures in which:

Figures 1 to 3 illustrate the production of a cable fitting with a field-control element that comprises a curved section that is formed by everting the tubular component, respectively in a schematic lateral sectional view;

Figure 4 illustrates an associated flow diagram for illus- trating steps of the production process; Figure 5 illustrates a schematic lateral sectional view of a cable termination with a field-control element arranged at a cable ; Figure 6 illustrates a schematic lateral sectional view of a cable joint with two field-control elements arranged at two cables ;

Figures 7 to 9 illustrate the production of a cable fitting with a further field-control element that comprises a curved section formed by everting the tubular component around a shaping element, respectively in a schematic lateral sectional view; Figure 10 illustrates a schematic lateral sectional view of a further field-control element comprising a curved section formed by everting the tubular component around a shaping element ; Figures 11 to 13 illustrate the production of a cable fitting with a further field-control element that comprises a curved section formed by rolling-up, respectively in a schematic lateral sectional view; Figures 14 to 16 illustrate the production of a cable fitting with a further field-control element that comprises a curved section formed by rolling-up around a shaping element, respectively in a schematic lateral sectional view; Figures 17 to 19 illustrate the production of a cable fitting with a further field-control element that comprises a closed shape and two curved sections formed by everting the tubular component, respectively in a schematic lateral sectional view; Figure 20 illustrates arranging the field-control element of figure 18 that may be applied for an oil-filled cable fitting at a cable by means of rolling; Figure 21 illustrates a schematic lateral sectional view of a further field-control element having a closed shape that surrounds a shaping element;

Figures 22 to 25 illustrate partial regions of further field- control elements having a closed shape, respectively in a schematic lateral sectional view;

Figure 26 illustrates a schematic lateral sectional view of the use of a field-control element having a closed shape as a Faraday cage in a cable joint; and

Figure 27 illustrates a schematic lateral sectional view of a further field-control element. Figures 1 to 3 show, each in a schematic lateral sectional view, the production of a cable fitting 100 or, respectively, of an enveloping body of a cable fitting 100 that may be arranged at a cable or, respectively, the end of a cable (in particular a power cable) . The method steps of the production process carried out are furthermore depicted in the flow diagram of Figure 4 to which it will be referred in the following, as well .

In the process, a formed component 110 of an elastic and electrically conductive material is provided in a step 201 as depicted in Figure 1. The component 110 that is configured in the shape of a tube or, respectively, a tubular part comprises the shape of a straight hollow cylinder. The tubular component 110 may e.g. comprise a rubber material or a sili- cone material that is provided with electrically conductive particles, in particular sooty particles. The production of the tubular component 110 may e.g. be carried out by means of an injection-molding process. Due to the simple shape of the tube 110, an injection-molding tool used at this comprises a correspondingly simple injection mold. The tubular component 110 may also be produced by carrying out a cost-efficient extrusion process instead of an injection-molding process.

In a further method step 202, the tubular component 110 is partly everted as shown in Figure 2. In this manner, a double-layer area is provided in that two "layers" or, respectively, part sections of the component 110 that are arranged offset to each other directly adjoin one another. The elastic material properties of the component 110 further make it pos- sible that a section 111 present at one end of the component

110 is formed with a curvature or, respectively, rounded form by the everting that is in the following referred to as curved section 111. The round geometry of the curved section

111 offers the possibility of applying the everted tubular component 110 for field control as will be described further below. The curvature may e.g. correspond to a simple radius or a ( semi ) circular curvature, respectively, or may essentially follow such a circular course. As depicted in Figure 2, the component 110 may be everted in such a way that the two-layer area or, respectively, double- layer area starting from the curved section 111 extends only over a part of the entire length of the everted component 110, and that the external section is shorter than the inter- nal section. Differing from such a configuration, it is also possible to evert the component 110 such that the component 110 is e.g. essentially provided in a double-layer configuration over its entire length (not depicted) . In a further method step 203, the everted tubular component 110 is embedded in an insulation medium. As depicted in Figure 3, an insulating housing part 120 is configured for this purpose that is essentially pipe-shaped and that surrounds or, respectively, encloses the tubular component 110 including its curved section 111. An insulating silicone material e.g. comes into question as a material for the housing part 120. The housing part 120 is arranged around the component

110 such that only an inner side or, respectively, inner surface of the component 110 is exposed that is flush with an internal surface of the housing part 120. At this, the housing part 120 and the component 110 enclose a common continu- ous recess that is e.g. circular-cylindrical as depicted in Figure 3 and that serves as internal space for receiving a cable in the area of its end section.

Forming the housing part 120 is e.g. carried out by means of an injection-molding process. At this, the applied injection- molding tool or, respectively, a part of the injection- molding tool may also be applied in everting the component 110 which is carried out previously (step 202) . For this purpose, the provided or, respectively, the straightly-extending tubular component 110 of Figure 1 may be slid onto a rod- shaped holding element ("mandrel") of the injection-molding tool and be everted on it. Subsequently, the holding element provided with the everted component 110 may be inserted in a mold into that molten or, respectively, flow-able material of the housing part 120 is injected in order to injection-mold around the component 110.

The housing part 120 with the everted component 110 as depicted in Figure 3 constitutes an enveloping body of a cable fitting 100. Apart from the housing part 120 and the component 110, the cable fitting 100 may also comprise further elements such as contact elements, further housing parts etc. This will be further elaborated below in context with Figures 5 and 6 that show possible embodiments of the cable fitting 100 in the form of an end termination 101 (Figure 5) and in the form of a cable joint or sleeve 102 (Figure 6) . Further elements of a cable fitting 100 are produced by means of fur- ther (typical) processes and production steps that will not be further referred to.

Due to the curved section 111, the component 110 may serve as field-control element 110 of the cable fitting 100. At this, the cable fitting 100 is with the field-control element 110 positioned in the area of the cut-back edge of an (outer) conductive layer of a cable so that the field-control element 110 may effect an equalization or, respectively, reduction of the electrical field that is increased at this point and, resulting therefrom, the danger of discharges, breakdowns or flashovers may be avoided. Due to the simple curved shape of the field-control element 110, the cable fitting 100 is in particular suitable for the use in a power cable that is ap- plied in the medium-voltage area. This may include operating voltages in the range between 6 kV and 42 kV.

As described above, the curved section 111 in the cable fitting 100 is formed by everting the (previously straight) tu- bular component 110. At this, the curved section 111 comes from an inner surface or, respectively, an inner side of the component 110 that may in a simple manner be formed in a smooth and even way. Therefore, generating the curvature does not require any extensive further treatment. This fact and the possibility of applying cost-efficient materials or, respectively, "standard materials" for the component 110 allow for a simple and cost-efficient production of the cable fitting 100. The following Figures 5 and 6 depict possible embodiments of a cable fitting including an everted field-control element 110. In the frame of the production of these cable fittings or, respectively, their enveloping bodies, the above- described method steps may be carried out in a corresponding manner. Figure 5 shows a schematic lateral sectional view of a cable terminal 101 that is arranged at an end of a cable 140. The cable 140 is e.g. a medium-voltage cable that is applied in the medium-voltage range. The cable termination 101 by means of which the cable 140 may be connected to another device such as e.g. a transformer comprises a cable shoe 130 and an enveloping body comprising a pipe-shaped insulating housing part 121 and an everted field-control element 110 embedded in the housing part 121. The housing part 121 and the field- control element 110 enclose an internal space in that the cable 140 is received in the area of its end section.

The cable 140 comprises (from the exterior to the interior) an insulating jacket 141, a shielding 142, an outer conduc- tive layer 143, an insulation 144 and an inner conductor 145. At this, the inner conductor 145 may be configured of multiple wires that are surrounded by an inner conductive layer (not depicted) . The shielding 142 may be configured as a shielding braid or wire netting, respectively.

As indicated in Figure 5, the individual elements of the cable 140 are removed or, respectively, stepped with respect to each other at various positions. At this, the exposed inner conductor 145 is connected to the cable shoe 130. The cable shoe 130 may e.g. be configured as a crimp-cable shoe and may be connected to the inner conductor 145 by means of crimping.

As indicated in Figure 5, a cut-back edge 150 is provided at the end of the outer conductive layer 143 due to cutting back. From this, a strongly inhomogeneous course of the electric field may result at this point during operation of the cable 140. Therefore, the cable termination 101 is adjusted to the cable 140 and arranged at the cable 140 such that the field-control element 110 is positioned in the area of the cut-back edge 150 and may provide for an equalization of the electric field distribution or, respectively, a reduction of the field intensity. At this, the field-control element 110 is with its curved section aligned in the direction of the cable's end and the field-control element 110 lies against the outer conductive layer 143 as well as against the insulation 144 of the cable 140 in order to reliably contact the outer conductive layer 143.

As is furthermore indicated in Figure 5, the shielding 142 may be guided out at a side of the cable termination 101 that is positioned opposite of the cable shoe 130 and it may be guided away from the cable 140. At this point, the cable termination 101 or, respectively, its housing part 121 may e.g. comprise a contact device in order to connect the shielding 142 to an earthing point. Figure 6 shows a schematic lateral sectional view of a cable joint 102 by means of which two cables or medium-voltage cables 140, respectively, are connected to each other. Each cable 140 comprises a configuration corresponding to the cable 140 depicted in Figure 5 with an insulating jacket 141, a shielding 142, an outer conductive layer 143, an insulation 144 and an inner conductor 145. These cable elements are again stepped with respect to each other at various points. For further details regarding the cables 140 it is referred to the above description of Figure 5.

The cable joint 102 comprises a connecting device 127, an enveloping body comprising a pipe-shaped insulating housing part 122 having two everted field-control elements 110 embedded in the housing part 122 as well as, as is indicated in Figure 6 by means of a dotted line, one or multiple further housing parts 125 arranged around the housing part 122. The housing part 122 and the field-control elements 110 embedded therein enclose an internal space in that end sections of the cables 140 and the connecting device 127 are arranged. The inner conductors 145 of the two cables 140 are connected to each other or contacted, respectively, by means of the con- necting device 127 that is e.g. configured as a compression connector .

The two field-control elements 110 of the cable joint 102 are positioned in the area of the cut-back edges 150 of the cables 140 and may consequently cause an equalization of the electric field distribution or, respectively, a reduction of the field intensity at these points. At this, the field- control elements 110 are aligned to the respective cable ends or, respectively, the connecting device 127 with their curvatures, and the field-control elements 110 lie against the outer conductive layer 143 and against the insulation 144 of the associated cables 140 in order to reliably contact the outer conductive layer 143.

At the cable joint 102, as is depicted in Figure 6, the shieldings 142 of the cables 140 may laterally be guided past the housing part 122. With regard to this configuration, the further housing parts 125 may provide for an electric connec- tion of the shieldings 142 of the cables 140.

By means of the following figures, further possible embodiments of geometric field-control elements or, respectively, cable fittings having such field-control elements and corre- sponding production processes will be explained, wherein the field-control elements may also come from tubular components that comprise curved sections formed by everting. Therein, it is pointed out that regarding already-described details that refer to similar or congruent features and aspects, applica- ble materials, an operating mode, possible advantages etc. it is referred to the preceding description. Furthermore, attention is drawn to the possibility that features and aspects that are mentioned with reference to one of the embodiments may also be applied in other embodiments as described in the following, except for cases of e.g. clear dependencies or inconsistent alternatives. In the field-control element 110 as described above, the curvature or, respectively, radius of the curved section 111 may be predetermined mainly by the material thickness of the respective tubular component 110. In the case of applications with comparably small voltages (e.g. a voltage levels of up to 24 kV) , relatively small radiuses are sufficient for a reliable field control. Higher voltage levels, however, typically require larger curvatures or radiuses of curvature, respectively. This may be effected as the case may be by con- figuring the tubular component 110 with a larger wall thickness. However, for providing a relatively large radius of curvature, starting from a certain thickness, this approach may be associated with a disproportionate high material usage and with complicating or even preventing the everting. Such disadvantages may be avoided in the embodiments as described in the following.

Figures 7 to 9 show, each in a schematic lateral sectional view, the production of a further cable fitting 200 or, re- spectively, of an enveloping body of such a cable fitting 200 that may be arranged at a cable end. At this, it is also referred to the flow diagram of Figure 4.

In the process, as is depicted in Figure 7, a straight tubu- lar component 210 of an elastic and electrically conductive material (such as e.g. a conductive rubber material or a conductive silicone material) is provided in a step 201. For this, e.g. an injection-molding process or a cost-efficient extrusion process may be carried out.

Furthermore, within the step 201, a shaping element 230 is provided. The shaping element 230 may, as depicted in Figure 7, be arranged at the tubular component 210 such that the shaping element 230 circumferentially encloses an area of the tubular component 210. At this, the shaping element 230 may comprise a circumferential closed shape, in particular a ring shape. Furthermore, it may be provided that the shaping ele- ment 230 lies against the tubular component 210 and contacts the outer side of the component 210 in the state as depicted in Figure 7. In a further method step 202, the tubular component 210 is everted over the shaping element 230 as depicted in Figure 8, thereby forming a curved section 211 being present at one side or, respectively, end of the component 210. The curved section 211 whose shape or, respectively, curvature is prede- termined by the shaping element 230 provides for the possibility to use the everted tubular component 210 for field control .

As is depicted in Figure 8, the tubular component 210 in its everted state may completely enclose the shaping element 230. At this, the tubular component 210 may in essence completely lie against the shaping element 230. The tubular component 210 furthermore comprises a double-layer area that is offset with regard to the shaping element 230, sections of the com- ponent 210 adjoining to each other in the double-layer area. This double-layer area may extend over a relatively small part of the length of the component 210, as depicted in Figure 8. Alternatively, it is possible that the double-layer area extends over a larger length or as well to an end of the everted component 210 that is positioned opposite to the curved section 211.

In a further method step 203, the tubular component 210 being everted around the shaping element 230 may be embedded in an insulation medium so that, as depicted in Figure 9, a pipe- shaped housing part 220 is formed that encloses the component 210 including its curved section 211. At this, it is provided that an exposed inner surface of the component 210 is flush with an inner surface of the housing part 220 and that the housing part 220 and the component 210 enclose a common recess suitable for receiving a cable. For forming the housing part 220 that may e.g. comprise an insulating silicone material, an injection-molding process may again be carried out. At this, it may be provided to arrange the tubular component 210 together with the shaping element 230 at a rod-shaped holding element of an injection- molding tool, to hereupon put or bend the tubular component 210 over the shaping element 230 and to subsequently carry out the actual injection-molding around the everted component 210 in the manner as described above in conjunction with Fig- ure 3.

The arrangement shown in Figure 9 also constitutes an enveloping body of a cable fitting 200 in that the everted component 210 with the curved section 211 may act as field-control element 210. For this purpose, the cable fitting 200 is positioned in the area of a cut-back edge of an (outer) conductive layer of a cable (in particular a cable for power transmission, e.g. the above-described cable 140), so that the field-control element 210 may cause an equalization or, re- spectively, a reduction of the electric field that is increased at this point. At this, the field-control element 210 is aligned in the direction of the cable end with its curved section 211. The cable fitting 200 may furthermore comprise additional elements such as contact elements, further housing parts etc. as well as be configured as a cable termination or alternatively as a cable joint, wherein in the framework of the production of such devices, method steps according to the ap- proach as shown in Figures 7 to 9 may be carried out. In a configuration in the form of a cable termination, a design comparable to Figure 5 may e.g. be provided, wherein the field-control element 210 instead of the field-control element 110 is embedded in the housing part 121. In a configura- tion in the form of a cable joint, a design comparable to

Figure 6 may e.g. be provided, wherein two field-control elements 210 instead of the two field-control elements 110 and having curved sections 211 opposing each other are embedded in the housing part 122. For further details, it is referred to the above description of Figures 1 to 6 that may apply here in an analogue manner.

The use of the shaping element 230 provides the opportunity to configure the tubular component 210 relatively thin-walled and to still configure the curved section 211 with a relatively large curvature or, respectively, a relatively large radius of curvature. Hereby, a reliable field control may be achieved for applications having higher voltages, e.g. higher than 24 kV. The thin-walled configuration of the tubular component 210 is associated with material savings and thus with cost savings.

Insulating materials as well as electrically conductive materials may come into consideration for the shaping element 230. Preferably, the materials of the tubular component 210 and the shaping element 230 are adapted to each other or, re- spectively, those two components 210, 230 comprise similar or the same (basic) materials (such as a rubber or silicone material) . This in particular applies with respect to the expansion behavior of the two components 210, 230 in order to e.g. allow for arranging the cable fitting 200 at a cable in a pre-expanded state. Furthermore, it may be considered as the case may be to additionally agglutinate the two components 210, 230 and/or the adjacent layers of the everted component 210 in the double-layer area. For this purpose, the shaping element 230 and/or a part of an external side of the tubular component 210 may be provided with an adhesive prior to everting the tubular component 210 or prior to arranging the shaping element 230 at the tubular component 210.

Any arbitrary cross-section shapes may be provided for the shaping element 230 around that the tubular component 210 is everted for forming the curved section 211. Apart from the essentially round or, respectively, oval shape as depicted in Figures 7 to 9, other shapes such as e.g. a drop shape may come into consideration as well. A possible modification that will be described in more detail further below is shown in Figure 10. The shape of the curved section 211 of the tubular component 210 is predetermined by the cross-section shape of the shaping element 230. By means of a corresponding configuration of the respectively applied shaping element 230 it is therefore possible to implement the curved section 211 with a simple radius, or also with another geometry or outline than a simple radius, e.g. with a funnel-shaped geometry.

The advantages described above with regard to the component 110 are also made possible for the component 210 everted over the shaping element 230. In particular, generating the curved section 211 does not require any extensive further treatment since the curved section 211 comes from an inner surface or inner side of the component 210 that may be configured smoothly and evenly in a simple manner. Furthermore, cost- efficient materials or, respectively, standard materials may be used for the component 210, but also for the other element 230. A simple and cost-efficient production is thus also possible with regard to the cable fitting 200.

Figure 10 depicts a schematic lateral sectional view of a further everted tubular component 210 that may be used for field control. For forming the curved section 211, the component 210 is at this everted around a shaping element 231 that comprises a "more circular" shape and is enlarged compared to the shaping element 230 of Figures 7 to 9. Furthermore, the double-layer area of the everted component 210 is configured in a longer way. The everted component 210 shown in Figure 10 may also in a corresponding manner be embedded in an insulation medium or, respectively, a housing part 220 in order to form an enveloping body of a cable fitting 200 (not de- picted) . Figures 11 to 13 show, each in a schematic lateral sectional view, the production of a further cable fitting 300 or, respectively, of an enveloping body of such a cable fitting 300 that may be arranged at a cable end. At this, it is also re- ferred to the flow diagram of Figure 4.

In the method, as depicted in Figure 11, a straight tubular component 310 of an elastic and electrically conductive material (such as e.g. a conductive rubber material or a conduc- tive silicone material) is provided in a step 201. This may be implemented by carrying out e.g. an injection-molding or extrusion process.

In a further method step 202, the tubular component 310 is rolled-up in the area of an end, as shown in Figure 12. Due to rolling-up which equates with "continuously" or repeatedly everting the tubular component 310, the tubular component 310 comprises a curved section 311 at the respective end. In this manner, the component 310 may be used for field control. The curved section 311 formed by the rolling-up may be circular, or may essentially follow such a circular course. In the everted or, respectively, rolled-up area of the tubular component 310, the individual adjacent layers of the component 310 may essentially be in direct contact with each other. As the case may be, it is also possible to agglutinate the layers of the component 310 in the rolled-up area, by which the component 310 is prevented from unrolling. For this purpose, an adhesive may be applied on an external side of the component 310 in the area to be rolled up before the rolling-up.

In a further method step 203, the partly rolled-up tubular component 310 may be embedded in an insulation medium so that, as depicted in Figure 13, a pipe-shaped housing part 320 is formed that encloses the component 310 including its curved section 311. At this, it is provided that an exposed inner surface of the component 310 is flush with an inner surface of the housing part 320 and that the housing part 320 and the component 310 enclose a common recess suitable for receiving a cable. By the embedding, the shape of the rolled- up component 310 may (also) be fixated and an unrolling may be prevented.

Forming the housing part 320 that may e.g. comprise an insulating silicone material may again be carried out by means of an injection-molding process. At this, it may be provided to arrange the tubular component 310 at a rod-shaped holding element of an injection-molding tool, to subsequently roll up the tubular component 310 and afterwards to carry out the actual injection-molding around the everted component 310 in the manner as described above with respect to Figure 3. The arrangement of Figure 13 represents an enveloping body of a further cable fitting 300 in that the component 310 having the curved section 311 may serve as field-control element 310. Thereby, the cable fitting 300 with the field-control element 310 is positioned in the area of a cut-back edge of an (outer) conductive layer of a cable (in particular a power cable, e.g. the above-described cable 140) so that the field- control element 310 may cause an equalization or, respectively, a reduction of the electric field increased at this point. At this, the field-control element 310 is aligned in the direction of the cable end with its curved section 311.

The cable fitting 300 may furthermore comprise additional elements such as contact elements, further housing parts etc. as well as be configured as a cable termination or alterna- tively a cable joint, wherein the production of such devices may be carried out by means of method steps according to the approach as indicated in Figures 11 to 13. In a configuration as cable termination, a design comparable to Figure 5 may e.g. be provided, wherein the field-control element 310 in- stead of the field-control element 110 is embedded in the housing part 121. In a configuration as cable joint, a design comparable to Figure 6 may e.g. be provided, wherein instead of the two field-control elements 110 two field-control element 310 having curved sections 311 opposing each other are embedded in the housing part 122. For further details, it is referred to the above description of Figures 1 to 6 that may apply here in an analogue manner.

Rolling or, respectively, rolling-up the tubular component 310 also provides the possibility of configuring the component 310 with a relatively small wall thickness and, in spite of the thin-walled configuration, implementing the curved section 311 with a relatively large curvature or, respectively, a relatively large radius of curvature. Thus, reliable field control with applications having higher voltages, e.g. higher than 24 kV, may be achieved and, furthermore, it is made possible to save material and thus costs. Thereby, the size of the curvature or, respectively, of the radius of curvature depends on the rolled-up portion or, respectively, the number of rolled-up layers of the tubular component 310. By rolling-up the tubular component 310 in order to form the curved section 311, the above-described further advantages are also rendered possible. In particular, generating the curved section 311 does not require any extensive further treatment since the curved section 311 comes from an inner surface or inner side of the component 310 that may in a simple manner be formed in a smooth and even way. Also, cost- efficient materials or, respectively, standard materials may be used for the component 310. Thus, a simple and cost- efficient production of the cable fitting 300 is possible.

With regard to the previously-described rolled-up configuration of a field-control element 310 the additional use of a shaping element may also be considered. For illustration, Figures 14 to 16 depict the production of a further cable fitting 301 or, respectively, an enveloping body of such a cable fitting 301 that may be arranged at a cable end. This cable fitting 301 essentially comprises the same configura- tion as the previously-described cable fitting 300 and may also be produced in a simple and cost-efficient manner.

In the method, as is depicted in Figure 14, a (thin-walled) tubular component 310 of an elastic and electrically conductive material (such as e.g. a conductive rubber material or a conductive silicone material) is again provided (step 201) . Moreover, a shaping element 330 is provided that may be arranged such at the tubular component 310 that, as depicted in Figure 14, the shaping element 330 circumferentially encloses an area of the tubular component 310. The shaping element 330 may comprise a circumferential closed shape, in particular a ring shape. As shown in Figure 14, the shaping element 330 may also comprise a circular cross-section shape. Further- more, it may be provided that the shaping element 330 lies against the tubular component 310 and contacts the outer side component 310 in the state as illustrated in Figure 14.

As shown in Figure 15, the tubular component 310 is subse- quently rolled-up over the shaping element 330, thereby forming a curved section 311 at a side of the component 310 (step 202) . Due to the curved section 311 that may be circular or essentially follow such a course, the component 310 may be used for field control. In the everted or, respectively, rolled-up area of the tubular component 310, the individual adjacent layers of the component 310 and/or the shaping element 330 and the section of the component 310 directly opposite to the element 330 may essentially be in direct contact. Furthermore, as the case may be, it may be provided to agglu- tinate the two components 310, 330 and/or the layers of the rolled-up component 310 with each other in the rolled-up area for better maintaining the rolled-up state. For this purpose, an adhesive may be applied to the shaping element 330 and/or a part of an outer face of the tubular component 310 prior to the rolling-up or prior to arranging the shaping element 330 at the tubular component 310. Compared to the procedure as shown in Figure 12, according to that the tubular component 310 is only rolled-up around itself, the additional use of a shaping element 330 provides the possibility of achieving a larger curvature or, respec- tively, a larger radius of curvature with a smaller number of layers of the component 310 arranged adjacent to each other. In this configuration, comparable to the approach as described with respect to the Figures 7 to 9, the shaping element 330 may be made of an insulating or an electrically con- ductive material. Furthermore, it may be considered to adapt the materials of the component 310 and the shaping element 330 to each other, in particular with respect to their expansion behavior or, respectively, to use similar or the same (basic) materials for the two components 310, 330.

Subsequently to rolling-up the tubular component 310 around the shaping element 330, embedding the tubular component 310 in an insulation medium may again be provided (step 203) so that, as depicted in Figure 16, a pipe-shaped housing part 320 is formed that encloses the component 310 including its curved section 311. Thereby, it is provided that an exposed inner surface of the component 310 is flush with an inner surface of the housing part 320 and that the housing part 320 and the component 310 enclose a common recess suitable for receiving a cable. By the embedding, the shape of the rolled- up component 310 may (also) be fixated and an unrolling may be prevented. For this purpose, an injection-molding process according to the method as described above may be carried out again (i.e. arranging the tubular component 310 together with the shaping element 330 at a rod-shaped holding element, thereupon rolling-up the tubular component 310 over the shaping element 330 and injection-molding around the rolled-up component 310) . The arrangement of Figure 16 constitutes an enveloping body of a further cable fitting 301 in that the component 310 with the curved section 311 may be used as field-control element 310. The cable fitting 301 may, as the cable fitting 300, comprise additional elements, and may be configured e.g. as a cable termination (having a possible configuration comparable with Figure 5) or alternatively as a cable joint (having a possible configuration comparable with Figure 6) . For further details, it is referred to the above description.

Figures 17 to 19 show, each in a schematic lateral sectional view, the production of a further cable fitting 400 or, re- spectively, of an enveloping body of such a cable fitting 400 that may be arranged at a cable end. At this, it is also referred to the flow diagram of Figure 4.

In the method, as depicted in Figure 17, a straight tubular component 410 of an elastic and electrically conductive material (such as e.g. a conductive rubber material or a conductive silicone material) is provided in a step 201. For this purpose, e.g. an injection-molding or extrusion process may be carried out.

In a further method step 202, the tubular component 410 is everted at two different positions, as depicted in Figure 18, thereby forming two curved sections 411, 412 on opposite sides of the component 410. Due to the curved sections 411, 412 that may each be ( semi ) circular or essentially follow such a course, the component 410 may be used for field control. As it is further shown in Figure 18, the ends of the twice-everted component 410 are further connected to each other, the component 410 thus comprising a continuous closed shape. A corresponding connection area that may e.g. be present in the middle between the two curved sections 411, 412 is indicated in Figure 18 with the reference numeral 415. Connecting the component 410 at the ends with itself may e.g. be carried out by means of agglutinating or welding the com- ponent 410. The closed circumferential shape of the tubular component 410 that comprises a double-layer section between the two curved sections 411, 412 may be used for moving the component 410 to a desired position by simply rolling it on a further element such as in particular a cable. For such an operation mode, the internal space enclosed by the component 410 between the layers is preferably provided with a lubricant 417. This will be explained further below with respect to Figure 20.

The component 410 connected to itself may also be embedded in an insulation medium (step 203) so that a pipe-shaped housing part 420 (e.g. of an insulating silicone material) is formed as shown in Figure 19, the pipe-shaped housing part 420 enclosing the component 410 including the curved sections 411, 412. Hereby, it is provided that an exposed inner surface of the component 410 is flush with an inner surface of the housing part 420 and that the housing part 420 and the component 410 enclose a common recess suitable for receiving a cable. For this purpose, an injection-molding process according to the above-described procedure may be carried out again (i.e. arranging the tubular component 410 at a rod-shaped holding element, thereupon everting the component 410 on both sides for forming the curved sections 411, 412 and connecting the ends of the component 410, and subsequently injection-molding around the component 410) .

The arrangement of Figure 19 represents an enveloping body of a further cable fitting 400, wherein the component 410 may serve as field-control element 410. In this respect, option- ally one of the two curved sections 411, 412 of the field- control element 410 may be used for field control. At this, also, the cable fitting 400 with the field-control element 410 is positioned in the area of a cut-back edge of an

(outer) conductive layer of a cable (in particular a power cable, e.g. the above-described cable 140) so that the field- control element 410 may cause an equalization or, respectively, reduction of the electric field increased at this point by means of one of the two curved sections 411, 412. At this, the respective curved section 411 or 412 is aligned in the direction of the cable end. The cable fitting 400 may furthermore comprise additional elements such as contact elements, further housing parts etc. as well as be configured as a cable termination, or alternatively a cable joint, wherein the production of such devices may be carried out by means of method steps according to the approach as indicated in Figures 17 to 19. In a configuration as cable termination, a design comparable with Figure 5 may e.g. be provided, the field-control element 410 instead of the field-control element 110 being embedded in the housing part 121. In a configuration as cable joint, a design compa- rable to Figure 6 may e.g. be provided, wherein instead of the two field-control elements 110 two field-control element 410 are embedded in the housing part 122. For further details it is referred to the above description of Figures 1 to 6 which may apply here in an analogue manner.

Everting the tubular component 410 for forming the curved sections 411, 412 also allows for the above-described advantages. In particular, generating the curved sections 411, 412 does not require any extensive further treatment since the curved sections 411, 412 come from an inner surface or, respectively, an inner side of the component 410 that may in a simple manner be formed in a smooth and even way. Furthermore, cost-efficient materials or, respectively, standard materials may be used for the component 410. Thus, a simple and cost-efficient production is also possible with respect to the cable fitting 400.

As has been indicated above, the component or, respectively, field-control element 410 connected to itself may be moved on a further element by means of simply rolling it. This operation mode is depicted in Figure 20 by the example of a cable 140. The field-control element 410 that is configured accord- ing to Figure 18 and is at this not embedded in an insulation medium or housing part 420 may be moved along the cable 140 by means of rolling as indicated by means of arrows in the schematic sectional view of Figure 20. Hereby, the field- control element 410 may be positioned at a desired point, in particular in the area of a cut-back edge 150 of the cable 140 present between an outer conductive layer 143 and an insulation 144 in a simple manner. Conventionally, an elastic field-control element is pushed- on, or is provided on a supporting body in a pre-expanded manner and is being guided down from the supporting body on a cable during installation ("cold-shrinking technique") . However, relatively high pushing forces may occur in the push-on technique. The cold-shrinking technique, on the contrary, involves a limited storage time due to the stretched storing. In contrast thereto, the roll-able field-control element 410 provides the advantage of a simple installation. The field- control element 410 may also essentially be stored in an un- stretched manner so that the storing time is not limited due to high material strains.

As is further indicated in Figure 20, the roll-able field- control element 410 that is not embedded in an insulation me- dium may in particular be used in an oil-filled cable fitting 401. The cable fitting 401 that may e.g. be present as a ca ble termination comprises a corresponding housing 421. Subsequently to positioning the field-control element 410, the housing 421 is arranged at the cable 140 such that the field- control element 410 (apart from further not depicted elements) is received in the housing 421. Subsequent thereto, the housing 421 may be filled up with oil as an insulating medium . In order to allow for rolling the field-control element 410 as simply as possible, the inner space enclosed by the field- control element 410 is preferably provided with a lubricant 417. In this respect, a liquid or, respectively, semi-liquid lubricant 417, such as e.g. a silicone oil or silicone grease may come into consideration. Alternatively, the use of a solid or, respectively, mineral lubricant 417 such as e.g. talcum is possible. At this, prior to connecting the ends of the respective tubular component 410 or prior to twofold- everting the component 410, the lubricant 417 is arranged at the component 410 such that after connecting the ends the lubricant 417 is arranged in the enclosed internal space. The internal space may in essence be completely filled up by the lubricant 417.

The above-described rolling of the component or, respectively, field-control element 410 may also be made use of for the (optional) method step of Figure 19 of the embedding in a housing part 420. In this respect, it may be provided to bring the component 410 in the closed shape shown in Figure 18 by twofold-everting and connecting the ends, subsequently "rolling up" the component 410 onto a holding element (man- drel) of an injection-molding tool and then forming the housing part 420 by injection-molding around the component 410.

With respect to the previously-described embodiment of a field-control element 410 connected with itself and having a closed shape, the additional use of a shaping element over that the formed component 410 is everted may also come into consideration. One possible embodiment is explained in more detail in the following. Figure 21 depicts a further field-control element 410 comprising two curved sections 411, 412 in a schematic lateral sectional view. Within the enclosed internal space, a shaping element 430 is additionally provided that comprises a circumferential closed shape, in particular a ring shape. The shap- ing element 430 that essentially comprises a combination of two different oval-shaped sections in the cross-sectional shape may be made of an insulating or an electrically conduc- tive material. In this configuration, it may again be considered to adapt the materials of the component 410 and of the shaping element 430 to each other, in particular with respect to the expansion behavior or, respectively, to use similar or the same (basic) materials for the two components 410, 430.

Producing the field-control element 410 of Figure 21 may be carried out by first arranging the shaping element 430 at the straight tubular component 410 shown in Figure 17. Thereupon, the two-fold everting and connecting of the ends of the component 410 as described above may be carried out, the shaping element 430 thus being arranged in the internal space.

Rolling the field-control element 410 on a further element such as in particular a cable is also possible in the embodiment according to Figure 21, thus allowing for the use in an oil-filled cable fitting 401. Furthermore, (optionally) embedding the field-control element 410 in an insulation medium or, respectively, housing part 420 may come into consideration. In order to allow for rolling the field-control element 410 as simply as possible, the use of a corresponding lubricant 417 is again preferably provided, in this embodiment together with the shaping element 430, within the enclosed internal space. For this purpose, prior to connecting the ends of the tubular component 410 or prior to the twofold-everting of the component 410, the lubricant 417 and the shaping element 430 may be arranged at the component 410 such that after connecting the ends, the lubricant 417 and the shaping element 430 are arranged in the enclosed internal space. For further details, it is referred to the above description.

The use of the shaping element 430 in a corresponding manner provides the possibility of configuring the component 410 in a relatively thin-walled manner and to implement the two curved sections 411, 412 with relatively large curvatures or, respectively, radiuses of curvature. Thus, it is possible to use the component 410 for field control in applications with higher voltage levels (e.g. higher than 24 kV) .

As is further depicted in Figure 21, the shaping element 430 as shown here comprises oval-shaped partitions differing in their cross-sections, wherein in particular the lateral rounding sections over that the component 410 is everted for forming the curved sections 411, 412 and that consequently determine the shape of the curved sections 411, 412 comprise differing shapes and curvatures. In this manner, also the curved sections 411, 412 comprise differently-sized curvatures or radiuses of curvature. This configuration may e.g. be used thus that by means of the component 410 different field controls may be implemented and that the component 410 may be used for applications with different voltage levels. In this respect, either the curved section 411 or the other curved section 412 may be used for field control and may be positioned in the area of a cable-cut-back edge. Differing from the embodiment shown in Figure 21, the shaping element 430 may also be configured having another cross- sectional shape. In this respect, any arbitrary cross- sectional shapes are again possible that may in particular be in sections oval, round and/or drop-shaped. Depending on the corresponding cross-sectional shape it is again possible to implement the curved sections 411, 412 with another outline than a simple radius, e.g. with a funnel-shaped outline.

With respect to a field-control element 410 having a closed shape, further modifications may moreover come into consideration. In the following, possible embodiments are described in more detail with respect to Figures 22 to 25 which show schematic lateral sectional views of (upper) partial regions of such field-control elements 410. At this, it is pointed out that the above-described aspects (such as e.g. production by twofold-everting and connecting the ends, embedding in an insulation medium, installation on a device or cable by roll- ing, use of a lubricant in an enclosed internal space, etc.) may also apply to these embodiments.

In the field-control element 410 as illustrated in Figure 22, the two curved sections 411, 412 comprise slightly larger curvatures or, respectively, radiuses of curvature in comparison to the embodiment of Figure 18, and the curved sections 411, 412 are slightly bulged out in outward direction. This is implemented without using a shaping element in the enclosed internal space. For such a configuration, the use of e.g. a material having higher bending strength may come into consideration for the component 410.

The field-control element 410 according to Figure 23 com- prises a shaping element 431 in the enclosed internal space that is essentially circular in its cross-section. At this, the shaping element 431 is (only) arranged in the area of the curved section 411 in order to impart a corresponding outline to the curved section 411. The other curved section 412, how- ever, is formed only by everting.

Instead of one single shaping element, multiple separate shaping elements having a circumferential closed shape (in particular a ring shape) may also be provided in the enclosed internal space. In this respect, Figure 24 shows a further possible embodiment of a field-control element 410 having two shaping elements 432, 433 arranged in the internal space. The shaping element 432 that is arranged in the area of the curved section 411 is essentially configured drop-shaped in its cross-section. The other shaping element 433 arranged in the area of the curved section 412, on the contrary, comprises an oval cross-sectional shape.

Figure 25 depicts a further possible embodiment of a field- control element 410 in that a single shaping element 434 is again arranged in the enclosed internal space. At this, the shaping element 434 comprises part sections in the area of the curved section 411, 412, the cross-sectional shapes of the part sections corresponding to the shaping elements 432, 433 of Figure 24. These part sections are connected to each other via a relatively thin connecting section.

A field-control element 410 connected to itself and having two curved sections 411, 412 may not only be used for field control in the area of a cut-back edge of a cable. It is also possible to use it as what is known as a "Faraday cage" in a cable fitting or cable joint, respectively. For illustration, Figure 26 depicts a schematic lateral sectional view of a cable joint 402 by means of which two cables 140 are connected to each other. The cable joint 402 comprises a housing 422 and within the housing 422 a connecting device 127 (e.g. a compression connector) by means of that inner conductors of the cables 140 are connected to each other.

In the area of the connecting device 127 a field-control element 410 is arranged within the housing 422, the field- control element 410 surrounding the connecting device 127. The field-control element 410 comprises two curved sections 411, 412 being formed by everting, the curved sections 411, 412 being configured symmetrically with respect to each other (as possible) . For this purpose, a shaping element 435 having a corresponding symmetrical outline is preferably arranged in the internal space of the field-control element 410, as depicted in Figure 26.

The cable joint 402 may e.g. be an oil-filled cable joint the housing 422 of which is filled-up with oil as insulating medium. Alternatively, an embodiment in that the field-control element 410 is embedded in the housing 422 or a corresponding housing part is also possible. With the cable joint 402, the field-control element 410 may be used as Faraday cage in order to maintain the area enclosed by the field-control element 410 in that the connect- ing device 127 is arranged free of electrical fields. A corresponding high-voltage potential is applied to the field- control element 410 through a contact with the connecting device 127 (not depicted) .

Moreover, the field-control element 410 may be used for field control, as well. Here, a field equalization takes place with respect to a shielding provided at the housing 422 that surrounds the field-control element 410 (not depicted) . At this, in particular the partitions of the curved sections 411, 412 of the field-control element 410 that are directed to the outside (with respect to the longitudinal axis of the field- control element 410) come into effect. Figure 27 depicts a schematic lateral sectional view of a further tubular component 170 that may be applied in a cable fitting (e.g. the cable fitting 100 of Figure 3) for field control. Comparably to the tubular component 110 as shown in Figure 2, the tubular component 170 is everted on one side, resulting in a curved section 171. At this, the curved section 171 comprises a larger curvature compared to the curved section 111 of the component 110 of Figure 2 and it is slightly bulged out to the outside. This is implemented without using a shaping element. For such a configuration, the use of a material having a higher bending strength may e.g. come into consideration for the component or, respectively, field-control element 170. The field-control element 170 again comprises a double-layer area adjacent to the curved section 171.

The embodiments as explained on the basis of the figures are preferred or exemplary embodiments of the invention. Apart from the described and depicted embodiments, further embodiments are conceivable that may comprise further modifications and/or alterations of everted field-control elements and cable fittings (or their enveloping bodies, respectively), or combinations of described features. In particular, it is possible to provide cable assemblies or, respectively, cable fittings in the shape of e.g. cable end terminations (comprising one field-control element) or cable joints (comprising two field-control elements) that may comprise differing shapes or geometries as well as further elements and structures than the embodiments as depicted in the figures, in particular in the Figures 5 and 6. Differing shapes and geometries are also possible for folded or, re- spectively, everted field-control elements as well as for corresponding shaping elements.

Furthermore, it is pointed out that the materials as described above are only to be seen as examples and that the use of other materials or, respectively, plastic materials may be considered for cable fittings and everted field- control elements. Furthermore, processes and process steps differing from the described ones may be carried out in the frame of a production process as the case may be.

Concerning the field-control element 110 as described with respect to Figures 1 to 6, additionally agglutinating the individual layers may e.g. also come into consideration. With respect to the everting around a shaping element, as illustrated in Figure 8, only a partly-everting around the shaping element may also be provided in an alternative embodiment. In this manner, the shaping element is only partly enclosed by the respective tubular component. In this embodi- ment, additionally agglutinating those two elements may also come into consideration.

Concerning the field-control element 410 depicted in Figure 24, a potential modification consists in arranging more than two shaping elements in the enclosed internal space. Furthermore, it is pointed out that all of the above- described field-control elements having curved sections by upending or, respectively, everting (and potential modifications of the same) may also be used in oil-filled cable fit- tings. For example, the field-control element 110 of Figure 2 may also be used in the cable fitting 401 shown in Figure 20 instead of the field-control element 410 without embedding it in an insulation medium or, respectively, a housing part 120. However, embedding the field-control element 110 in an insu- lation medium or housing part 120 as described with respect to Figure 3 may also be provided for such embodiments in order to achieve a stiffening of the field-control element 110 and thus to provide the field-control element 110 with a higher strength of shape. In this respect, an assembly in- eluding the insulation medium or housing part 120 and the field-control element 110 being embedded therein within an oil-filled cable fitting may come into consideration. Such approaches also apply to the other above-described field- control elements.

With respect to the oil-filled cable fitting 401 of Figure 20, it is furthermore possible to configure it as a cable joint. In such an embodiment, it may be provided to position two of the roll-able field-control elements 410 (or also of the other field-control elements) at cut-back edges of two cables 140 connected to each other and to arrange the field- control elements 410 within the housing 421.

Furthermore, it is pointed out that with respect to the above-described oil-filled cable fittings or, respectively, cable fittings that may be filled with oil, such cable fittings may alternatively be filled with an insulating gas (e.g. SF6) . Such a gas filling may for example be carried out for test purposes. At this, also, everted tubular components according to the above approaches may be used for field control . A further alternative is that a field-control element formed by everting a tubular component is only partly or in a part section electrically conductive. For example, the component may comprise a basic body (pipe-shaped before the everting) of an elastic insulating material such as e.g. a rubber or silicone material, that is provided with an electrically conductive coating, e.g. a conductive varnish on the basis of silicone. At this, the coating may be arranged on the basic body, in particular on its internal side, in the area of the curved section (to be produced) before or after the everting. A reliable field control may also be effected by such a conductive coating.

Claims

A cable fitting (100, 101, 102, 200, 300, 301, 400, 401, 402) for mounting to a cable (140), comprising a field- control element (110, 210, 310, 410) of an electrically conductive material, characterized in that the field-control element is a partly everted tubular component (110, 210, 310, 410) comprising a curved section (111, 211, 311, 411, 412) being formed by the everting .

The cable fitting according to claim 1,

further comprising a housing part (120, 121, 122, 220, 320, 420) of an insulating material, the field-control element (110, 210, 310, 410) being embedded in the housing part (120, 121, 122, 220, 320, 420) .

The cable fitting according to any one of the preceding claims ,

wherein the cable fitting is a cable termination (101) or a cable joint (102), and wherein the field-control element (110, 210, 310, 410) comprises an electrically conductive rubber material or an electrically conductive silicone material.

The cable fitting according to any one of the preceding claims ,

further comprising a shaping element (230, 231, 330, 430, 431, 432, 433, 434, 435), the tubular component (210, 310, 410) being everted over the shaping element (230, 231, 330, 430, 431, 432, 433, 434, 435) .

The cable fitting according to any one of the preceding claims , the tubular component (310) being partly rolled-up for providing the curved section (311) .

The cable fitting according to claim 5,

the tubular component (310) being rolled-up over a shaping element (330) .

The cable fitting according to any one of the preceding claims ,

wherein the tubular component (410) comprises two curved sections (411, 412) being formed by everting the tubular component (410), and wherein the tubular component (410) comprises ends being connected to each other.

The cable fitting according to claim 7,

wherein the tubular component (410) encloses an internal space, and wherein a lubricant and/or at least one shaping element (430, 431, 432, 433, 434, 435) is arranged in the internal space.

A method of producing a cable fitting (100, 101, 102, 200, 300, 301, 400, 401, 402) comprising the steps of: providing a tubular component (110, 210, 310, 410) of an electrically conductive material, and partly everting the tubular component in order to form a field-control element (110, 210, 310, 410) comprising a curved section (111, 211, 311, 411, 412) .

The method according to claim 9,

further comprising forming a housing part (120, 121, 122, 220, 320, 420) of an insulating material, the field-control element (110, 210, 310, 410) being embedded in the housing part (120, 121, 122, 220, 320, 420) . The method according to any one of claims 9 or 10, wherein providing the tubular component (110, 210, 310, 410) includes performing an injection-molding process or performing an extrusion process.

The method according to any one of claims 9 to 11, further comprising providing a shaping element (230, 231, 330, 430, 431, 432, 433, 434, 435), wherein the curved section (211, 311, 411, 412) is formed by everting the tubular component (210, 310, 410) over the shaping element (230, 231, 330, 430, 431, 432, 433, 434, 435) .

13. The method according to any one of claims 9 to 12,

wherein the curved section (311) is formed by partly rolling-up the tubular component (310) .

The method according to any one of claims 9 to 13, wherein two curved sections (411, 412) are formed by spectively everting the tubular component (410), and wherein ends of the tubular component (410) are connected to each other.

A field-control element for a cable fitting, characterized by a partly everted tubular component (110, 210, 310, 410) comprising a curved section (111, 211, 311, 411, 412) being formed by the everting.