ELECTRICAL CONDUCTOR ARRANGEMENT

Description

[0001] The invention relates to an electrical conductor arrangement comprising an electrical conductor, an electrically insulating sheath arranged around at least one conductor section of the conductor, and an electrically conductive sheath arranged around an insulating sheath section of the insulating sheath.

[0002] Such conductor arrangements are used in and / or on many electrical devices, for example, in electrical feedthroughs through housing openings or on cables, where the electrically conductive sheath of a conductor arrangement serves, for example, to shield against electric fields. A particular weak point of such a conductor arrangement is the area where the sheath ends around the insulating jacket. In this area, high field strengths of an electric field at the end of the sheath, which acts as an electrical electrode, can lead to significant discharges ("sparks") on the surface of the insulating jacket, which can damage or destroy the insulating jacket in a short time. This effect is further amplified if the end of the sheath has sharp edges, because small radii of an edge of the sheath lead to particularly high electric field strengths in the area surrounding the edge.

[0003] Measures that influence local electric field strengths are referred to as field control. Elements for field control are referred to as field control elements. Depending on the field control requirements, different measures are used. For example, it may be sufficient to make the radii of an electrode large enough to keep the field strength at the interface below the electrical strength of the insulating sheath. This type of field control is referred to as geometric field control.

[0004] Alternatively, weakly conductive coatings in the form of varnishes, tapes, or filled plastics can be applied to the surface of the insulating sheath as field control elements. The electric field drives a current through these materials, which, together with their resistance, leads to a voltage drop. This voltage drop, in turn, defines the potential along the surface. The more precisely the resistance can be adjusted, the more precisely the potential and thus the field can be controlled. This type of field control is called resistive field control. However, the field strength for alternating voltage is not constant along such a system, since part of the current flows capacitively via the insulating sheath to the conductor of the conductor arrangement. As a result, the voltage drop is lower further away from the sheath. This can be counteracted by reducing the resistance along the length of the field control element.

[0005] Another possibility is to use materials whose conductivity is strongly dependent on the applied field strength. At particularly exposed areas, such materials become more conductive, further reducing the field strength. This type of field control is called nonlinear field control.

[0006] Alternatively, so-called refractive materials with a high relative permittivity can be used for AC systems. These materials "break" the electric field at their interface with the insulation, thus pushing it away from the electrode edge. This type of field control is called refractive field control.

[0007] DE 77 22 352 U1 discloses a termination for a plastic-insulated power cable. This includes a field control cone with a continuous conductor wire embedded in its sheath.

[0008] DE 17 77 892 U discloses a device for producing terminations for high-voltage cables, high-voltage bushings for transformers, converters, or the like from castable, curable, or self-curing insulating compounds with conductive inserts for potential control. Concentric rings of conductive materials, particularly metal, can be inserted into the mold before the compound is poured. The rings can be secured in the mold by webs or threads made of an insulating material with chemical and physical properties corresponding to the casting compound.

[0009] The invention is based on the object of providing an electrical conductor arrangement of the type described above with a field control that can be implemented simply, precisely and adapted to the respective requirements, in particular for electrical bushings and cables.

[0010] The object is achieved according to the invention by an electrical conductor arrangement having the features of claim 1, a method for producing an electrical conductor arrangement having the features of claim 10, an electrical feedthrough having the features of claim 11 and a cable having the features of claim 12.

[0011] Advantageous embodiments of the invention are the subject of the subclaims.

[0012] An electrical conductor arrangement according to the invention comprises an electrical conductor, an electrically insulating sheath arranged around at least one conductor section of the conductor, an electrically conductive sheath arranged around a first insulating sheath section of the insulating sheath, and an electrically conductive yarn wound around a second insulating sheath section of the insulating sheath adjacent to the first insulating sheath section for electrical field control. A winding device is used, in particular, for winding. A rotational movement is performed for winding. For example, the conductor arrangement is rotated with the insulating sheath. It is also possible, for example, to fix the conductor arrangement with the insulating sheath during winding and to wind the yarn around the conductor arrangement onto the insulating sheath using a rotating device. The yarn (the electrically conductive yarn) can be wound directly onto the insulating sheath.The yarn (the electrically conductive yarn) is or will be wound directly onto the insulating sheath.

[0013] An electrical conductor arrangement according to the invention thus comprises an electrically conductive yarn for field control. The yarn is wound around an insulating sheath section of an insulating sheath, which has an adjacent insulating sheath section between a conductor and an electrically conductive sheath of the conductor arrangement. The yarn is used as a field control element for an electric field at the end of the electrically conductive sheath. By selecting the material from which the yarn is made and the design of the yarn winding, a precise field control that can be variably adapted to the respective requirements can be realized. This field control requires only a small installation space and is therefore particularly advantageous when space is limited.

[0014] In one embodiment of the invention, a yarn end portion of the yarn is connected to a sheath end portion of the sheath, for example, by gluing. This advantageously fixes a yarn end portion of the yarn near the sheath end portion of the sheath, and the yarn is electrically coupled to the sheath galvanically and / or capacitively.

[0015] In a further embodiment of the invention, the yarn is wound helically around the second insulating sheath section. In particular, the helical winding of the yarn can have different pitches. Thus, the pitch of the helical winding and its variation along the course of the winding allow the electrical resistance of the winding and its local variation in a direction parallel to the conductor to be flexibly adapted to the respective field control requirements.

[0016] In a further embodiment of the invention, the yarn has a lower specific electrical conductivity than the sheath. In a further embodiment of the invention, the wound yarn has an electrical resistance in the range between 1 MΩ / m and 100 MΩ / m. These embodiments of the invention are adapted to typical designs of electrically conductive sheaths.

[0017] In further embodiments of the invention, the yarn is made of a polyamide fiber coated with an electrically conductive carbon-containing material, or of a fiber mixture comprising at least one polyamide fiber and one electrically conductive carbon fiber, or of a metallic fiber. These materials enable the production of electrically weakly conductive wound yarn and are therefore particularly suitable for the production of yarn for a conductor arrangement according to the invention.

[0018] In a further embodiment of the invention, the yarn is surrounded by a protective layer or protective sheath. This advantageously protects the yarn against mechanical and / or chemical damage. Furthermore, by selecting the appropriate material and / or designing the protective layer or protective sheath, the dielectric strength of the system consisting of the yarn and the protective layer or protective sheath can be increased.

[0019] In one embodiment of the invention, the yarn is fixed to the second insulating sheath section by a hardening or hardenable resin. This advantageously stabilizes the yarn and protects it against local and global mechanical displacements. In particular, in the case of a helical winding of the yarn, the local pitches of the winding can be fixed.

[0020] Accordingly, in the method according to the invention for producing a conductor arrangement according to the invention, a curing or curable resin is applied to the second insulating sheath section to fix the yarn to the second insulating sheath section, and the yarn is wound around the second insulating sheath section before the resin on the resin has completely cured.

[0021] An electrical feedthrough according to the invention through a housing opening of a housing of an electrical device has a conductor arrangement according to the invention, the sheath of which is electrically connected to the housing and is guided through the housing opening with the conductor and the insulating sheath.

[0022] A cable according to the invention has a conductor arrangement according to the invention.

[0023] Since an electrical feedthrough according to the invention and a cable according to the invention have a conductor arrangement according to the invention, their advantages result from the above-mentioned advantages of a conductor arrangement according to the invention.

[0024] The above-described properties, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more readily understood in connection with the following description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. FIG 1 shows a partially sectioned view of an embodiment of an electrical conductor arrangement, FIG 2 shows a partially sectioned view of an embodiment of an electrical feedthrough, FIG 3 shows a partially sectioned view of an embodiment of a cable.

[0025] Corresponding parts are provided with the same reference numerals in the figures.

[0026] FIG 1 shows an embodiment of an electrical conductor arrangement 1 according to the invention in a partially sectioned view, wherein the upper part of the FIG 1 The conductor assembly 1 is shown in section. The conductor assembly 1 comprises an electrical conductor 3, an electrically insulating insulating jacket 5, an electrically conductive sheath 7, an electrically conductive yarn 9 for electric field control, a resin layer 11, and a protective layer 13.

[0027] The insulating sheath 5 is arranged around a conductor section 3.1 of the conductor 3. The sheath 7 is arranged around a first insulating sheath section 5.1 of the insulating sheath 5. The resin layer 11 is applied to an outer surface of a second insulating sheath section 5.2 of the insulating sheath 5, adjacent to the first insulating sheath section 5.1. The yarn 9 is wound helically around the second insulating sheath section 5.2 on the resin layer 11. The resin layer 11 fixes the yarn 9 to the second insulating sheath section. 5.2.A yarn end section 9.1 of the yarn 9 is electrically conductively connected to a sheath end section 7.1 of the sheath 7 and is firmly bonded to the sheath end section 7.1 by an adhesive 15. The sheath end section 7.1 has an outer diameter that tapers conically toward the second insulating sheath section 5.2. The protective layer 13 is arranged around the yarn 9 and the resin layer 11. The protective layer 13 is shown transparent, but can also be opaque.

[0028] The conductor 3 is made of copper, for example. The insulating sheath 5 is made of polyetheretherketone (PEEK), cross-linked polyethylene (VPE), polyvinyl chloride (PVC) or a comparable polymer, oil-paper, ceramic, silicone, resin-impregnated mica tapes, or synthetic resin. The sheath 7 is made of stainless steel, for example. The yarn 9 is made of a polyamide fiber encased in an electrically conductive carbon-containing material, a fiber mixture comprising at least one polyamide fiber and one electrically conductive carbon fiber, or a thin metallic fiber. The resin layer 11 is made of a curing or hardening resin, for example, epoxy resin. The protective layer 13 is also made of a curing or hardening resin, for example, in particular of the same resin as the resin layer 11.

[0029] The yarn 9 has a lower specific electrical conductivity than the sheath 7. For example, the wound yarn 9 has an electrical resistance in the range between 1 MΩ / m and 100 MΩ / m.

[0030] During the production of the conductor assembly 1, a base body is first produced, comprising the conductor 3, the insulating sheath 5, and the sheath 7. Resin for the resin layer 11 is then applied to the second insulating sheath section 5.2. The yarn 9 is then wound around the sheath end section 7.1 and the second insulating sheath section 5.2, pressed against the resin, and bonded to the sheath end section 7.1 by the adhesive 15. Finally, material for the protective layer 13 is applied to the yarn 9 and the resin layer 11.

[0031] FIG 2shows a partially sectioned illustration of an embodiment of an electrical feedthrough 17 according to the invention through a housing opening 19.1 of an electrically conductive housing 19 of an electrical device. The electrical device is, for example, an electrical machine such as a motor, a generator or a transformer, or an electrical switching device such as a circuit breaker or a disconnector. The feedthrough 17 comprises a FIG 1 formed conductor arrangement 1 and a seal 21. The housing 19 and the seal 21 are shown in section, the conductor arrangement 1 is as in Figure 1shown partially in section. The insulating sheath section 5.2 of the conductor arrangement 1 is arranged within the housing 19. The sleeve 7 protrudes from the housing opening 19.1. The seal 21 runs annularly around the sleeve 7, connects the sleeve 7 in an electrically conductive manner to the housing 19 and seals the housing opening 19.1. For example, the sleeve 7 is made of a material that contains graphite. The conductor 3 is connected or connectable to a current path of the electrical equipment (in the case that the electrical equipment is an electrical machine, the conductor 3 is connected, for example, to a winding of the machine; in the case that the electrical equipment is an electrical switching device, the conductor 3 is connected, for example, to a switching contact of the switching device). The sleeve 7 and the housing 19 are connected, for example, to earth potential.

[0032] FIG 3 shows analogous to FIG 1a partially sectioned view of an embodiment of a cable 23 according to the invention. The cable 23 comprises a FIG 1 formed conductor arrangement 1, which forms a first cable end of the cable 23, wherein the insulating sheath 5 extends around the conductor 3 to a (not shown) second cable end of the cable 23. The second cable end can be formed like the first cable end.

[0033] The Figures 1 to 3The exemplary embodiments of conductor arrangements 1 shown can be modified in various ways. In particular, the helical winding of the yarn 9 can have locally different pitches in order to change the electrical resistance of the winding along its course and to adapt it to the requirements of field control. Furthermore, instead of a protective layer 13, a protective sheath can be provided which envelops the yarn 9 and the resin layer 11. Further exemplary embodiments of a conductor arrangement 1 according to the invention have no resin layer 11 and / or no protective layer 13 at all. In further exemplary embodiments, the yarn 9 is not electrically connected to the sheath 7, but is only capacitively coupled to the sheath 7.

[0034] Although the invention has been illustrated and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims

1. Electrical conductor assembly (1) comprising - an electrical conductor (3) - an electrically insulating jacket (5) disposed around at least one conductor section (3.1) of the conductor (3), - an electrically conductive sleeve (7) disposed around a first insulating jacket section (5.1) of the insulating jacket (5), characterised in that, for electric field control, an electrically conductive yarn (9) is wound around a second insulating jacket section (5.2) of the insulating jacket (5) adjacent to the first insulating jacket section (5.1), wherein the yarn (9) is made of a polyamide fibre sheathed with an electrically conductive carbon-containing material or wherein the yarn (9) is made of a fibre blend comprising at least a polyamide fibre and an electrically conductive carbon fibre.

2. Conductor assembly (1) according to claim 1, wherein a yarn end section (9.1) of the yarn (9) is bonded, e.g. adhesively, to a sleeve end section (7.1) of the sleeve (7).

3. Conductor assembly (1) according to claim 1 or 2, wherein the yarn (9) is helically wound around the second insulating jacket section (5.2).

4. Conductor assembly (1) according to claim 2, wherein the helical winding of the yarn (9) has different pitches.

5. Conductor assembly (1) according to one of the preceding claims, wherein the yarn (9) has a lower specific electrical conductivity than the sleeve (7).

6. Conductor assembly (1) according to one of the preceding claims, wherein the wound yarn (9) has an electrical resistance in the range between 1 MΩ / m and 100 MΩ / m.

7. Conductor assembly (1) according to one of claims 1 to 6, wherein the yarn (9) is made of at least one metallic fibre.

8. Conductor assembly (1) according to one of the preceding claims, wherein the yarn (9) is surrounded by a protective layer (13) or protective wrapper.

9. Conductor assembly (1) according to one of the preceding claims, wherein the yarn (9) is fixed to the second insulating jacket section (5.2) by a curing or curable resin.

10. Method for manufacturing a conductor assembly (1) according to one of the preceding claims, wherein - a curing or curable resin is applied to the second insulating jacket section (5.2) to fix the yarn (9) to the second insulating jacket section (5.2), and - the yarn (9) is wound around the second insulating jacket section (5.2) on the resin before the resin is completely cured.

11. Electrical bushing (17) through an enclosure opening (19.1) of an enclosure (19) of an item of electrical equipment, wherein the bushing (17) comprises a conductor assembly (1) according to one of claims 1 to 9, the sleeve (7) of which is electrically connected to the enclosure (19) and is fed through the enclosure opening (19.1) together with the conductor (3) and the first insulating jacket section (5.1) of the insulating jacket (5).

12. Cable (23) having a conductor assembly (1) according to one of claims 1 to 9.