Cable Joint

Abstract

The present invention relates to a cable joint (1) for connecting two current conductor parts for carrying a direct current, comprising a control member (3) and a conductive connector (2) surrounded by the control member (3), the connector (2) having a first receptacle (5) and a second receptacle (6), such that a conductor end (7) of the first conductive member (8) can be introduced into the first receptacle (5) to make an electrical contact between the connector (2) and the conductor end (7) of the first conductive member (8), such that a conductor end of the second conductive member can be introduced into the second receptacle (6) to make an electrical contact between the connector (2) and the conductor end of the second conductive member, and the control member (3) has insulatingly spaced concentric conductive control inserts (11-17) for resistive field control.

Description

[Technical field]

[0001] The present invention relates to a cable joint. [Background technology]

[0002] In low voltage technology cable joints are known as branching and connection joints for electrical installations. In high voltage technology (for operating voltages above 300 kV) there are significantly higher demands on cable connections with regard to insulation and charge loading. Moreover, it is known that especially high voltage cables have length limitations with regard to their manufacture. Particularly long connections of electrical conductors occur in the transmission of high voltage direct current. Summary of the Invention [Problem to be solved by the invention]

[0003] SUMMARY OF THE DISCLOSURE It is an object of the present invention to provide a cable joint which allows reliable high voltage direct current transmission over long cable sections. [Means for solving the problem]

[0004] This problem is solved by a cable joint for connecting two current conductor parts for carrying a direct current, comprising a control member and a conductive connecting member surrounded on its longitudinal side by the control member, the connecting member having a first receiving member and a second receiving member, such that a conductor end of the first conductive member can be introduced into the first receiving member to form an electrical contact between the connecting member and the conductor end of the first conductive member, and such that a conductor end of the second conductive member can be introduced into the second receiving member to form an electrical contact between the connecting member and the conductor end of the second conductive member, and the control member has insulatingly spaced, approximately or nearly concentric, conductive control inserts (e.g. aluminium foil) for resistive field control.

[0005] The cable joint is designed for direct current. The essential difference between cable joints for alternating current and direct current applications lies in the manner of field control, i.e. the control of the field distribution in the area of ​​the cable connection or connector. Field control preferably requires a field distribution as uniform as possible between the current-carrying conductor and earth (i.e. mainly the external surroundings). This is expediently achieved in that the impedance between the control inserts is as uniform as possible. In this case, the capacitance between the control inserts plays an important role for alternating current, whereas the resistive component of the impedance between the control inserts is important for direct current. This requires that the spacing between the control inserts is different for alternating and direct current applications. When determining the spacing between the control inserts, it is advantageous to achieve a compromise or optimization between a purely resistive control and a capacitive-resistive control, especially in applications where direct current coexists with an alternating current component. It is also conceivable to select the spacing between the control inserts to increase or decrease (depending on the respective temperature dependence of the resistance of the insulating material used) from the inside to the outside. In this way, the temperature effects of the operating temperature taken off the current conductors can be taken into account. In particular, the control inserts are insulatingally spaced apart, i.e. separated from one another by an insulating layer. In particular, the insulating layer consists of suitable synthetic materials, such as paper, cardboard, synthetic materials, fleeces, etc. The invention allows a reliable connection of the current conductor parts, which advantageously allows relatively long transmission distances. The inserted control inserts result in a linear resistive (or resistive-capacitive) voltage distribution and an optimal setting and operability of the dielectric properties of the control elements, so that the above-mentioned reliability of the current connection is achieved. The cable joint according to the invention further has the advantage that it can be configured for a reversible connection of the current conductor parts and can therefore be pulled apart again in the event of a required exchange.

[0006] To improve electrical insulation, it is advantageous to impregnate the control member with a resin, for example an epoxy resin.

[0007] With a view to possible use in high-voltage DC transmission systems, the control elements are made to withstand a voltage of at least 320 kV, which is achieved, for example, by appropriate dimensioning of the control elements.

[0008] According to a variant, the connectors are adapted to form a detachable connection by means of a press seat with the first and second conductor ends, respectively.

[0009] The cable joint preferably has a charge carrier conductor made of a conductive material, which is electrically connected to the outermost control insert and serves to conduct the surface charge carriers. During operation of the cable joint under DC voltage, charge carriers are formed on the surface of the control element. Such charge carriers are the cause of undesirable flashovers. To conduct the surface charge carriers, a charge carrier conductor is used, which is applied, for example, by coating, on the control element or on a strip of insulating material.

[0010] The control member is preferably provided on its outer side with a mounting flange for connection to the holding device of the first current conductor part, in such a way that the connection is mechanically strengthened and furthermore the cable end is prevented from falling out of the cable joint (e.g. when using large axial pulling forces).

[0011] According to one embodiment of the invention, the first and second openings are each conically shaped, such that the conductor end of the first current conductor part is guided through the first opening for establishing an electrical contact between the connector and the conductor end of the first current conductor part, and the conductor end of the second current conductor part is guided through the second opening for establishing an electrical contact between the connector and the conductor end of the second current conductor part. The cable joint thus has an inner cone at each end, into which the respective cable end can be inserted. For insulating fastening, the intermediate space between the cable end and the inner cone can be filled with a flexible insulating material, for example silicone. [Brief description of the drawings]

[0012] The invention will be further explained below on the basis of an embodiment shown in the drawings.

[0013] [Figure 1] FIG. 1 is a schematic diagram of a first embodiment of a cable joint according to the invention; [Diagram 2] FIG. 4 is a schematic diagram of a second embodiment of a cable joint according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In FIG. 1 a cable joint 1 for connecting two current conductor parts is shown. The cable joint 1 has a connector 2, the longitudinal side of which is surrounded by a control member 3. The dashed-dotted line 4 indicates the central axis of the device, which is also interpreted as the longitudinal axis of the cable joint. The connector 2 has a first receptacle 5 and a second receptacle 6. The conductor end 7 of the cable 8 is introduced into the first receptacle 5 through a first conical opening 9 of the control member 3, so that an electrical connection is formed between the conductor end 7 and the connector 2. The receptacles 5, 6 can have a suitable connection system, for example an inner plate, to facilitate contact. The intermediate space 19 between the conductor end 7 and the control member 3 is filled with a silicone material 19. The control member is provided with a second conical opening 10 and a second receptacle 6 for forming an electrical connection with a second conductor end of a second cable. The connector contains a conductive material, for example copper or aluminum.

[0015] A control member 3 is arranged concentrically with the connector 2. The control member 3 has concentric control inserts 11-17 for controlling the electric field. In the illustrated example, the control inserts 11-17 are formed as aluminium foils. The control inserts are spaced apart from one another by an insulating layer, which in the illustrated example comprises resin-impregnated paper.

[0016] A charge conductor 18 is arranged on the outside of the control member 3 and is electrically conductively connected to the outermost control insert 11. The charge conductor 18 conducts the surface charges that arise during DC operation to earth.

[0017] The cable joint 1 further comprises a housing 20 and a mounting flange 21. The mounting flange 21 is mechanically connected to a retention device 22 of the cable portion 8 during operation of the cable joint 1.

[0018] FIG. 2 shows another cable joint 30. The cable joint 30 has a connection 31, which is surrounded on its longitudinal side by a control member 32. The construction of the control member 32 corresponds essentially to the construction of the control member 3 of the cable joint 1 of FIG. 1. The difference with the embodiment of FIG. 1 is that the control member 32 has a conical end tapering axially outwards on both sides. Between the housing 33 of the cable joint 30 and the control member 32, intermediate chambers 34, 35 are provided on both sides of the cable joint 30, respectively. The intermediate chambers 34, 35 serve to accommodate the attachment members of the cable ends 36, 37 to be connected. For insulating fastening, the intermediate chambers can furthermore be provided with a flexible insulating material which surrounds the cable ends 36, 37. A mounting flange 38 on the outside of the housing 33 has a function corresponding to the mounting flange 21 of the cable joint 1 of FIG. 1.

Claims

1. A cable joint (1) for connecting two current conductor parts for carrying a direct current, comprising: A control member (3), a conductive connector (2) surrounded by the control member (3), the connector (2) having a first receptacle (5) and a second receptacle (6), such that the conductor end (7) of the first conductive member (8) can be introduced into the first receptacle (5) to form an electrical contact between the connector (2) and the conductor end (7) of the first conductive member (8), and such that the conductor end of the second conductive member can be introduced into the second receptacle (6) to form an electrical contact between the connector (2) and the conductor end of the second conductive member; having the control member (3) having insulatingly spaced concentric conductive control inserts (11-17) for resistive electric field control; Cable joint.

2. A cable joint (1) according to claim 1, A cable joint (1) in which the control member (3) is impregnated with resin.

3. A cable joint (1) according to claim 1 or 2, A cable joint (1) in which the control member (3) has a dielectric strength of at least 320 kV.

4. A cable joint (1) according to any one of claims 1 to 3, A cable joint (1) in which the connector (2) forms a detachable connection with the first and second conductor ends by press-fitting.

5. A cable joint (1) according to any one of claims 1 to 4, The cable joint (1), further comprising a charge conductor (18), the charge conductor (18) being connected to the outermost control insert (11) and configured to discharge surface charge carriers.

6. A cable joint (1) according to any one of claims 1 to 5, A cable joint (1) having a mounting flange (21) on the outside of the control member (3), the flange (21) being configured for connection with a retaining device (22) of the first conductive member (8).

7. A cable joint (1) according to any one of claims 1 to 6, a control member (3) having first and second openings (9, 10), each of which is formed in a conical shape, the conductor end (7) of the first conductive member (8) being guided through the first opening (9) to form an electrical connection between the connecting device (2) and the conductor end (7) of the first conductive member (8), and the conductor end of the second conductive member being guided through the second opening (10) to form an electrical connection between the connecting device (2) and the conductor end of the second conductive member.

8. 8. A high voltage energization system for guiding a direct current through first and second cables, the first and second cables being mechanically and electrically connected to each other by a cable joint according to any one of claims 1 to 7.

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