JPH1169555A - Method and device for mounting sleeve at connection position of two high-voltage cables - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a sleeve mounting method, so that the mechanical load to be applied to a sleeve can be reduced as much as possible in fitting the sleeve for insulation at the connection position of two high-voltage cables. SOLUTION: Because a cylindrical sleeve to be elastically expanded is mounted at the connection position of two high-voltage cables insulated with synthetic resin, the sleeve is elastically expanded by being pressed in its axial direction to a degree such that the sleeve is press-fitted to a cable core, when the sleeve is fitted to one cable core or when the sleeve is shifted to the connection position of a conductor. The sleeve is elastically expanded by a tightening device 7 comprising two pressing plates 71, 72, which are arranged on each end face of the sleeve and tightened to each other. The tightening device is movable in the axial direction inside a skeleton 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of power cable laying, in which a connection position of two synthetic resin insulated high-voltage cables is insulated and temporarily resilient to be disposed above a conductor connection position. The present invention relates to a method and an apparatus for attaching a prefabricated sleeve, which is spread out on a sleeve.

[0002]

2. Description of the Related Art When installing relatively long power cable installations, sleeves are provided for connecting individual production unit length cables, mainly to insulate conductor connection locations from the surroundings. In the past, the usual method of installing the insulation of the sleeve, whether for cables with paper or oil insulation or for cables with extruded synthetic resin insulation, is to use insulating tape. This was time consuming in the method of mounting. Recently, even for the voltage class 110 kV or more,
Instead of a tape wound sleeve, a prefabricated sleeve made of a rubber elastic material such as ethylene propylene rubber or silicone rubber has been successfully used. Such a sleeve comprises a shielding electrode and two control deflection plates, the volume of which increases as the voltage class increases. Moreover, the sleeve is elastically spread when mounted on the cable end and must be mounted by press-fitting on the cable insulation after mounting (see EP 0199742).

In order to attach a sleeve of the type mentioned above to the conductor connection of two high voltage cables insulated with synthetic resin, the sleeve is first elastically expanded by the action of a mechanical force and then expanded. It is known to fit one of the stripped cable ends in the bent state and temporarily fix the position outside a range to be a connection position later. In this case, the conductors at both cable ends are then connected to each other, and then the expanded sleeve is positioned above the conductor connection location,
Mechanical stress is reduced. In this known method, the sleeve is elastically expanded or temporarily held in this expanded state because the sleeve is formed by a cylinder whose inner diameter is larger than the insulating outer diameter of the cable core to be connected. This is performed by axially fitting the support into the shape of a support. This tubular support is removed again after the sleeve has been positioned over the conductor connection location, the expansion of the sleeve being partially eliminated, i.e. the sleeve is shrunk over the cable insulation in the region of the connection location. . In that case, in order to remove the cylindrical support, a holding plate in contact with the sleeve in the axial direction, a pulling head fitted to one end of the cylindrical support, and a linear driving device are provided. The support is removed by means of a drive, the distance between the holding plate and the pulling head being gradually increased by means of a drive (see EP 0 368 235). This method of mounting a prefabricated sleeve causes the temporary elastic expansion of the sleeve to exceed the required dimensions when mounted. On the other hand, when mounting the sleeve for a high voltage class up to 500 kV, if the sleeve is to be mounted on the cable core without elastically expanding in advance, the frictional force becomes so large that it cannot be controlled.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tubular elastically expandable sleeve made of a rubber elastic material and having the characteristics of the former part of claim 1 by using two synthetic resin insulated cables. Based on the method of mounting in the connection position, and further on the basis of the device with the features of the preamble of claim 2 for performing this method, this prior art minimizes the mechanical load on the sleeve. To improve it.

[0005]

According to the present invention, a tubular elastically expandable sleeve made of a rubber elastic material is first elastically expanded by the action of a mechanical force. In this state, it is fitted to one of the stripped cable ends, temporarily positioned outside the range that will be the connection position later, and then the conductors of both cable ends are connected to each other,
Subsequently, the position of the expanded sleeve is fixed on the conductor connection position, where mechanical stress is relieved and the sleeve is mounted at the connection position of the two synthetic resin insulated high-voltage cables. The sleeve is elastically expanded by strongly pressing in the axial direction, and the inner diameter of the sleeve is increased by about 3 times the difference between the inner diameter of the sleeve in the unexpanded state and the outer diameter of the cable insulation by the strong pressing in the axial direction. A cylindrical slide core which is spread by a value corresponding to a factor of 1 and which is slightly conically expanded at this end of the cable before fitting the expanded sleeve to the end of the cable. Over the conical end, fit the sleeve into the cable insulation, temporarily reposition the sleeve at the one cable end, and retake the slide core. It is solved by removing. The method expediently expands the sleeve, keeps the sleeve elastically expanded and relieves the stress of the sleeve, these devices being arranged on the end face of the sleeve and clamping together. A first device for forming a clamping device consisting of two pressing plates, wherein said clamping device is axially movable in a gantry, wherein said gantry clamps one cable end and fixes it axially. And an axially movable guide device for this cable end, and a device for tightening and axially fixing the second cable end.

[0006] The mounting technique thus formed avoids the use of a cylindrical support, and thus the overexpansion of the sleeve, and instead the axial expansion of the sleeve by adjusting the expansion of the inner diameter of the sleeve appropriately. The frictional force generated when shifting is reduced to a controllable magnitude. The sleeve fits into one end of the cable and is used to temporarily position the sleeve at this end of the cable and also to ultimately fix the position of the sleeve over the conductor connection location. Since the cable end is fitted with a slight pressing force, no bubbles are formed between the sleeve and the cable insulation when the sleeve is attached, which adversely affects the electric strength.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The mounting method formed in accordance with the present invention will be described in detail with reference to the embodiment of the prefabricated sleeve mounting apparatus shown in FIG. 1 and with reference to the steps shown in FIGS. Will be described.

FIG. 1 is a schematic and plan view of a base 1 from above.
This gantry is shown with two side guide elements 2 and 3 in the form of rails or pipes having a U-shaped cross section, which are mainly arranged parallel to one another, and holding the two guide elements at a fixed distance from each other. Not consisting of braces and. At the beginning and end of the gantry, one fixing device 4 and 5, respectively, are arranged, which are respectively high-voltage cables 10 and 15
Is provided with two retaining rings 41 and 51 each consisting of two half-plates. The gantry is further provided with an axially movable guide device 6, whereby the cable core 12 of the high-voltage cable 10 is guided in the center of the gantry 1 in the area between the fixing device 4 and the actual cable end. . The gantry is further provided with a tightening device 7, which comprises two pressing plates 71 and 72 which can move axially in the gantry and a screw rod 73, to which a nut 74 is attached.

The fixing device 5 is detachably connected to the gantry 1 so that a sleeve fitted in this area can be arranged at the beginning of the mounting. Further, although not shown, a lifting device (not shown) is attached to the pressing plates 72 and / or 71, whereby the tightening device 7 is moved in the axial direction. For this purpose, the pressure plates 71 and 72 are arranged to slide in or on the guide elements 2 and 3.

FIG. 1 shows a state in which two cables 10 and 15 to be connected are attached, that is, the insulation between the cable sheaths 11 and 16 and the cable cores 12 and 17 is removed. Therefore, the conductor ends 13 and 18 are bare. In this figure, the elastically expanding sleeve is not shown, but it is temporarily placed between the two pressing plates 71 and 72 when applying the process described below and is The cable core 12 is then fitted over the conductor connection location and thus over the cable core 17.

FIG. 2 shows the resiliently expanding sleeve 20 schematically as a cylinder, into which a slightly conically expanding pipe-shaped slide core 8 is inserted at one end 81 into the bore of the sleeve. Have been. The slide core 8 is arranged on the sleeve 20 with a loose or slight press fit. In the first mounting step, the end 81 of the slide core 8 is applied to the free end (see FIG. 1) of the cable core 12, and the conical end 81 is stripped of the cable insulation. About 2-3cm at the end
And centered on the free end of the conductor 13. The free end of the slide core 8 is temporarily supported. As shown in FIG. 3, pressing plates 71 and 72 are then arranged on the end surface of the sleeve 20, and these pressing plates are fastened to each other by a screw bar 73 and a nut 74.
At this time, the sleeve 20 is axially extended to such an extent that the expansion of the inner diameter is about 25 to 40% of the diameter difference between the unexpanded inner diameter of the sleeve and the cable insulation or cable core 12. Pressed. The degree of axial pressing required for this depends on the shape of the sleeve and is about 10 to 15% of its unpressed length.

Next, as shown in FIG.
The axially pressed, and thus elastically expanded, sleeve 20 is fitted onto the cable core 12. Thereafter, the slide core 8 is removed, and the conductor end 13 is free. The cable 15 with the free cable core 17 and the prepared conductor end 18 is then fitted to the cradle of FIG. 1 and the conductor connection element 19 is mounted on both conductor ends 13 and 18 ( (Fig. 5).

In FIG. 6, in the next step the resiliently expanded sleeve 20 is fitted centrally above the conductor connection location, and the sleeve is then relieved of its stress by loosening the clamping device. After removing the clamping device, the sleeve 20 is pressed into the cable cores 12 and 17 connected at the center of the conductor connection position as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for performing a method of the present invention.

FIG. 2 is a diagram showing a state in which a slide center is inserted into a sleeve in the process of the present invention.

FIG. 3 is a diagram in which a pressing plate is applied to an end surface of a sleeve and tightened.

FIG. 4 is a diagram illustrating a state where a cable core is inserted into a sleeve.

FIG. 5 is a diagram illustrating a state in which both conductor ends are connected by a conductor connection element.

FIG. 6 is a diagram illustrating a state in which a sleeve is fitted together with a pressing plate at a connection position between both conductor ends.

FIG. 7 is a diagram illustrating a state in which a pressing plate is removed from a connection position of both conductor ends and a sleeve is press-fitted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stand 2 Side guide element 3 Side guide element 4 Fixing device 5 Fixing device 6 Guide device 7 Clamping device 8 Slide core 10 Cable 11 Cable insulation 12 Cable core 13 Conductor end 15 Cable 16 Cable insulation 17 Cable core 18 Conductor end 19 Conductor connection element 20 Sleeve 41 Retaining ring 51 Retaining ring 71 Pressing plate 72 Pressing plate 73 Screw bar 74 Nut 81 Spread portion of slide core

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Mehmet Alp Germany 12157 Berlin Rubensstrasse 118

Claims (2)

[Claims] 1. A tubular elastically expandable sleeve made of rubber elastic material is first elastically expanded by the action of a mechanical force, and fitted in one of the stripped cable ends in the expanded state. Temporarily position outside the connection position with, then connect the conductors of both cable ends together,
Subsequently, the position of the unfolded sleeve is fixed on the conductor connection position, where the sleeve is mechanically relieved and the sleeve is mounted at the connection position of the two synthetic resin insulated high-voltage cables. The inner diameter of the sleeve is increased by about 3/3 of the diameter difference between the inner diameter of the sleeve in the unexpanded state and the outer diameter of the cable insulation in the unexpanded state. Before fitting the spread sleeve over one cable end, the cable end is fitted with a slightly conically expanded cylindrical slide core at this one end before fitting the spread sleeve over one cable end. After the conical end, the sleeve is fitted into the cable insulation and the slide is re-taken after the sleeve is temporarily positioned at the one cable end. Method of attaching the sleeve to the connecting position of the two high-voltage cables, characterized in Succoth. 2. A device for expanding a sleeve, a device for holding the sleeve elastically expanded, a device for displacing the expanded sleeve in the axial direction and fixing its position, and a device for relieving stress on the sleeve. These devices, which expand the sleeve (20), hold the sleeve elastically expanded and relieve the stress of the sleeve, are applied to the end face of the sleeve and clamped together. Forming a clamping device (7) consisting of two pressing plates (71, 72), and the clamping device (1)
A first device (4) for axially displacing the cable clamp, wherein the rack clamps one of the cable ends (10) in the axial direction and is axially displaceable for this cable end 2. A method as claimed in claim 1, further comprising a guide device (6) and a device (5) for clamping and axially securing the second cable end (15). apparatus.