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 Art

[0002] In low voltage technology, cable joints are known as branch and connection joints for electrical equipment. In high voltage technology (for operating voltages above 300 kV), there are particularly high requirements for cable connections regarding insulation and charge loading. Moreover, it is known that high voltage cables, in particular, have limitations in length with respect to their manufacture. Very long connections of electrical conductors occur in high voltage DC transmission.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The problem of the present invention is to provide a cable joint that enables reliable high voltage DC transmission over a long cable section.

Means for Solving the Problems

[0004] This problem is solved by a cable joint for connecting two current conductor portions for passing a DC current, having a control member and a conductive connector surrounded longitudinally by this control member, the connector having a first receptacle and a second receptacle, the conductor end of the first conductive member being adapted to be introduced into the first receptacle to form an electrical contact between the connector and the conductor end of the first conductive member, the conductor end of the second conductive member being adapted to be introduced into the second receptacle to form an electrical contact between the connector and the conductor end of the second conductive member, and the control member being provided with an insulatingly spaced, substantially or almost concentric, conductive control insert (e.g., aluminum foil) for resistive electric field control.

[0005] This cable joint is designed for DC current. The essential difference between cable joints for AC current applications and those for DC current applications lies in the manner of electric field control, i.e., the manner in which the electric field distribution in the area of ​​the cable connection or connector is controlled. Ideally, electric field control requires an electric field distribution that is as uniform as possible between the current-guiding conductor and ground (i.e., primarily the external environment). This is purposefully achieved by ensuring that the impedances between the control inserts are as uniform as possible. In this case, capacitance between control inserts plays a crucial role in AC currents, while resistance components of the impedance between control inserts are important in DC currents. This necessitates different spacing between control inserts in AC and DC current applications. When determining the spacing between control inserts, it is advantageous to compromise or optimize between purely resistive control and capacitive resistance control, especially in applications where DC current coexists with AC current components. Furthermore, it is possible to select spacing between control inserts that increases or decreases from the inside outward (depending on the temperature dependence of the resistance of the insulating material used). This allows for consideration of the temperature effect of the operating temperature drawn from the current conductor. In particular, the control inserts are insulatedly spaced apart, i.e., separated from each other by an insulating layer. The insulating layer is made of a suitable synthetic material such as paper, cardboard, synthetic material, or fleece. The present invention enables reliable connection between current conductor portions, which is advantageous as it allows for relatively long transmission sections. The inserted control inserts result in a linear resistive (or resistive-capacitive) voltage distribution and optimal setting and operation of the dielectric properties of the control member, achieving the reliability of current coupling described above. The cable joint according to the present invention has the further advantage of being able to be configured for reversible connection of current conductor portions, and therefore can be separated again when necessary for replacement.

[0006] To improve electrical insulation, it is advantageous to impregnate the control component with a resin, such as epoxy resin.

[0007] From the standpoint of usability in high-voltage DC transmission systems, control members are made to have a voltage tolerance of at least 320kV. This can be achieved, for example, by making the dimensions of the control members appropriate.

[0008] In the modified version, the connectors are made to form a detachable connection with the first and second conductor ends by press seats.

[0009] Preferably, the cable joint has a charge carrier deduct made of a conductive material, which is electrically connected to the outermost control insert and used for surface charge carrier deducting. When the cable joint is operated under a DC voltage, charge carriers form on the surface of the control member. Such charge carriers can cause undesirable flashouts. A charge carrier deduct is used to remove such surface charge carriers, which is attached, for example, by coating onto the control member or onto a strip made of an insulating material.

[0010] Preferably, a mounting flange is provided on the outside of the control member for connection to a retaining device for the first current conductor portion. This mechanically reinforces the connection and further prevents the cable end from detaching from the cable joint and falling off (for example, when using large axial tensile forces).

[0011] According to one embodiment of the present invention, the first and second openings are each formed in a conical shape, and the conductor end of the first current conductor portion is guided through the first opening to form an electrical contact between the connector and the conductor end of the first current conductor portion, and the conductor end of the second current conductor portion is guided through the second opening to form an electrical contact between the connector and the conductor end of the second current conductor portion. Thus, the cable joint has an internal cone at each end into which the cable end can be inserted. For insulating fixation, a flexible insulating material, such as silicon, can be filled into the intermediate chamber between the cable end and the inner cone. [Brief explanation of the drawing]

[0012] The present invention will be further described below based on the embodiments shown in the drawings.

[0013] [Figure 1] This is a schematic diagram of a first embodiment of the cable joint according to the present invention. [Figure 2] This is a schematic diagram of a second embodiment of the cable joint according to the present invention. [Modes for carrying out the invention]

[0014] Figure 1 shows a cable joint 1 for connecting two current conductor sections. The cable joint 1 has a connector 2 whose longitudinal side is surrounded by a control member 3. The dashed line 4 implies the central axis of the device, which can also be interpreted as the longitudinal axis of the cable joint. The connector 2 has a first receiver 5 and a second receiver 6. The conductor end 7 of the cable 8 is introduced into the first receiver 5 by passing through the conical first opening 9 of the control member 3, so that an electrical connection is formed between the conductor end 7 and the connector 2. The receivers 5 and 6 may have a suitable connecting system, such as an inner plate, to assist in contact. The intermediate chamber 19 between the conductor end 7 and the control member 3 is filled with a silicon material 19. The control member is provided with a second conical opening 10 and a second receiver 6 to form an electrical connection with the second conductor end of the second cable. The connector contains a conductive material, such as copper or aluminum.

[0015] The control member 3 is positioned concentrically with the connector 2. The control member 3 has concentric control inserts 11-17 for electric field control. In the illustrated example, the control inserts 11-17 are formed as aluminum foil. The control inserts are spaced apart by an insulating layer. In the illustrated example, the insulating layer is made of resin-impregnated paper.

[0016] A charge deductor 18 is positioned on the outside of the control member 3, and this is electrically connected to the outermost control insert 11. The charge deductor 18 guides the surface charge generated during DC operation to the ground.

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

[0018] Figure 2 shows another cable joint 30. The cable joint 30 has a connector 31 whose longitudinal side is surrounded by a control member 32. The configuration of the control member 32 is almost equivalent to the structure of the control member 3 of cable joint 1 in Figure 1. The difference from the embodiment in Figure 1 is that the control member 32 has conical ends on both sides that taper outward in the axial direction. Between the housing 33 of the cable joint 30 and the control member 32, intermediate chambers 34 and 35 are provided on both sides of the cable joint 30, respectively. The intermediate chambers 34 and 35 serve to accommodate the mounting members of the cable ends 36 and 37 to be connected, respectively. For insulating fixation, flexible insulating material can be further provided in the intermediate chambers to surround the cable ends 36 and 37. The mounting flange 38 on the outside of the housing 33 has a function equivalent to the mounting flange 21 of cable joint 1 in Figure 1.

Claims

1. A cable joint (1) for connecting two current conductors for conducting direct current, - Control member (3), - A conductive connector (2) surrounded by the control member (3), wherein the connector (2) has a first receiver (5) and a second receiver (6), and the conductor end (7) of the first conductive member (8) can be introduced into the first receiver (5) to form an electrical contact between the connector (2) and the conductor end (7) of the first conductive member (8), and the conductor end of the second conductive member can be introduced into the second receiver (6) to form an electrical contact between the connector (2) and the conductor end of the second conductive member, It has, The control member (3) has electrically insulating, spaced-apart, concentric conductive control inserts (11-17) for resistive electric field control. The cable joint (1) further includes a charge conductor (18), the charge conductor (18) is provided on the outer surface of the control member (3), is electrically connected to the outermost control insert (11), and is configured to discharge a surface charge carrier formed on the surface of the control member (3). Cable joint.

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

3. A cable joint (1) according to claim 1 or 2, The control member (3) is a cable joint (1) having an dielectric strength of at least 320 kV.

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

5. A cable joint (1) according to any one of claims 1 to 4, A mounting flange (21) is provided on the outside of the control member (3), and the flange (21) is configured for connection with the retaining device (22) of the first conductive member (8) in the cable joint (1).

6. A cable joint (1) according to any one of claims 1 to 5, The control member (3) comprises first and second openings (9, 10), each of which is formed in a conical shape, and the conductor end (7) of the first conductive member (8) is guided through the first opening (9) to form an electrical connection between the connector (2) and the conductor end (7) of the first conductive member (8), and the conductor end of the second conductive member is guided through the second opening (10) to form an electrical connection between the connector (2) and the conductor end of the second conductive member, cable Joint (1).

7. A high-voltage current supply system for guiding a direct current through first and second cables, A high-voltage energizing system in which the first and second cables are mechanically and electrically connected to each other by a cable joint as described in any one of claims 1 to 6.

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