JP4024927B2 - Method and apparatus for attaching a sleeve to the connection position of two high voltage cables - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
This invention is made in advance in the field of power cable laying, in which the connection position of two synthetic resin insulated high voltage cables is insulated and temporarily elastically spread for placement on the conductor connection position The present invention relates to a method and an apparatus for mounting a sleeve.
[0002]
[Prior art]
In order to connect individual manufacturing unit length cables when installing a relatively long power cable installation, a sleeve is mainly attached to insulate the conductor connection position from the surroundings. The conventional method used to install the sleeve insulation is to apply insulation tape, whether it is a cable with paper or oil insulation, or a cable with extruded synthetic resin insulation. This was a time consuming method of wearing. Use a pre-made sleeve made of rubber elastic material such as ethylene / propylene / rubber or silicon rubber instead of a sleeve wound with tape for the voltage class 110 kV or more recently. Has succeeded. Such a sleeve comprises a shielding electrode and two control deflection plates, and the volume increases as the voltage class increases. Moreover, this sleeve is elastically spread when it is attached to the end of the cable, and after being attached, it must be attached to the cable insulation by press fitting (see European Patent No. 0199742).
[0003]
In order to attach the above-mentioned type of sleeve to the conductor connection position of two synthetic resin insulated high voltage cables, the sleeve is first elastically expanded by the action of mechanical force and then in the expanded state A method of fitting to one of the peeled cable ends and temporarily fixing the position outside the range to be a connection position later is known. In this case, the conductors at both cable ends are then connected to each other, and the subsequently unfolded sleeve is positioned over the conductor connection location, and the mechanical stress is relieved. In this known method, the sleeve is elastically expanded or temporarily held in the expanded state because the sleeve has a cylinder whose inner diameter is larger than the outer diameter of the insulation of the cable core to be connected. This is performed by axially fitting to a shaped support. This cylindrical support is removed again after positioning the sleeve over the conductor connection position, in which case the expansion of the sleeve is partially eliminated, i.e. the sleeve is shrunk over the cable insulation in the area of the connection position. . In that case, in order to remove the cylindrical support, a holding plate that is in contact with the sleeve in the axial direction, a pulling head fitted to one end of the cylindrical support, and a linear drive device are provided. The apparatus is used, and the support is removed by gradually increasing the distance between the holding plate and the pulling head by means of a driving device (see European Patent No. 0368235). This method of attaching a pre-made sleeve allows the size of the temporary elastic expansion of the sleeve to exceed the required dimensions in the installed state. On the other hand, when the sleeve is mounted for a high voltage class up to 500 kV, if the sleeve is attached to the cable core without elastically spreading in advance, the frictional force becomes so large that it cannot be controlled.
[0004]
[Problems to be solved by the invention]
The object of the present invention is based on a method of mounting a cylindrical elastically spread sleeve made of a rubber elastic material at the connection position of two synthetic resin insulated cables, which has the features of the front stage of claim 1. Further, based on the apparatus having the features of the front part of claim 2 for carrying out this method, the conventional technique is to improve the mechanical load applied to the sleeve as small as possible.
[0005]
[Means for Solving the Problems]
According to the present invention, according to the present invention, a cylindrical elastically expanded sleeve made of a rubber elastic material is first elastically expanded by the action of a mechanical force, and one of the cable ends peeled off in the expanded state. And then temporarily position it outside the area where it will be connected later, then connect the conductors at both cable ends together, and then fix the position of the unfolded sleeve above the conductor connection position In this method, the mechanical stress is relieved and the sleeve is attached to the connecting position of the two synthetic resin insulated high voltage cables. The sleeve is elastically expanded by pressing the sleeve strongly in the axial direction. The inner diameter of the sleeve is expanded by a value that corresponds to about one third of the difference in diameter between the inner diameter of the sleeve and the outer diameter of the cable insulation when the inner diameter is not expanded due to strong axial pushing. Before fitting the cable to one cable end, place the cylindrical slide center slightly conically spread on this cable end, beyond the end of the cone. The problem is solved by fitting the sleeve to the cable insulation and removing the slide core again after temporarily positioning the sleeve at the one cable end. This method is expediently spread out the sleeve, holds the sleeve in an elastically expanded state, and these devices that relieve the stress on the sleeve are arranged on the end face side of the sleeve and fastened together. A first device for forming a fastening device composed of two pressure plates and for moving the shaft in the axial direction within the gantry, wherein the gantry fastens one cable end and fixes it in the axial direction. And an axially movable guide device for the cable end and an apparatus for fastening the second cable end and fixing it in the axial direction.
[0006]
In the mounting technique formed in this way, the use of a cylindrical support, thus avoiding excessive expansion of the sleeve, and instead of shifting the axial diameter by adjusting the expansion of the inner diameter of the sleeve to an appropriate amount, The resulting frictional force is reduced to a controllable magnitude. When the sleeve is fitted to one end of the cable and the sleeve is temporarily positioned on the end of the cable, and also when the position of the sleeve is finally fixed on the conductor connection position, the sleeve Since the end of the cable is fitted with a slight pressing force, air bubbles that adversely affect the electrical strength are not formed between the sleeve and the cable insulation when the sleeve is attached.
[0007]
【Example】
The mounting method formed in accordance with the present invention will be described in detail with reference to the embodiment of the apparatus for mounting a pre-made sleeve shown in FIG. 1 and with reference to the steps shown in FIGS.
[0008]
FIG. 1 shows a pedestal 1 schematically and in a plan view from above, the pedestal comprising two side guide elements 2 and 3 in the form of U-shaped rails or pipes, which are mainly arranged parallel to each other, It consists of braces (not shown) that hold the guide elements at a fixed distance from each other. One fixing device 4 and 5 is arranged at the beginning and end of the gantry, respectively, and each has one retaining ring 41 and 51 consisting of two halves for fixing the high-voltage cables 10 and 15, respectively. Yes. The gantry further includes a guide device 6 that is movable in the axial direction, whereby the cable core 12 of the high-voltage cable 10 is guided to the center of the gantry 1 in a range between the fixing device 4 and the original cable end. . Further, the fastening device 7 is arranged on the gantry, which comprises two pressing plates 71 and 72 that can move in the axial direction in the gantry and a screw rod 73, to which a nut 74 is attached.
[0009]
The fixing device 5 is detachably coupled to the gantry 1 so that a sleeve fitted in this range can be arranged at the beginning of the mounting. Furthermore, although not shown in figure, the raising / lowering apparatus is attached to the press plates 72 and / or 71, Thereby, the clamping apparatus 7 is moved to an axial direction. For this purpose, the pressing plates 71 and 72 are arranged to slide in or on the guide elements 2 and 3.
[0010]
In FIG. 1, the two cables 10 and 15 to be connected are shown attached, that is, the insulation between the cable sheaths 11 and 16 and the cable cores 12 and 17 is peeled off. Conductor ends 13 and 18 are bare. In this figure, the elastically spread sleeve is not shown, but this is temporarily placed between the two pressing plates 71 and 72 when applying the process described below, The cable core 12 is then fitted over the conductor connection location and thus over the cable core 17.
[0011]
FIG. 2 shows the sleeve 20 which is elastically spread out as a cylinder, in which a pipe-like slide core 8 which extends slightly conically at one end 81 is inserted into the hole of the sleeve. . The slide core 8 is arranged on the sleeve 20 with a loose or slight press fit. In the first mounting step, the end portion 81 of the slide core 8 is applied to the free end of the cable core wire 12 (see FIG. 1), and the conical end portion 81 is peeled off from the cable insulation. The end is covered with a length of about 2 to 3 cm, and the center position is aligned with the free end of the conductor 13. The free end of the slide core 8 is temporarily supported. As shown in FIG. 3, press plates 71 and 72 are then disposed on the end face of the sleeve 20, and these press plates are fastened together by a screw rod 73 and a nut 74. In that case, the sleeve 20 is axially extended to such an extent that the extension of its inner diameter is approximately 25 to 40% of the difference in diameter 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 is related to the shape of the sleeve and is about 10-15% of its unpressed length.
[0012]
As shown in FIG. 4, the sleeve 20 which is then axially pressed by the pressing plates 71 and 72 and thus elastically spread is fitted into the cable core 12. Thereafter, the slide core 8 is removed, and the conductor end 13 becomes free. A cable 15 having a free cable core 17 and a prepared conductor end 18 is then fitted into the gantry of FIG. 1 and a conductor connecting element 19 is mounted on both conductor ends 13 and 18 ( FIG. 5).
[0013]
In FIG. 6, the sleeve 20 that has been elastically expanded in the next step is fitted in the center above the conductor connection location, and then the sleeve is relaxed in its stress by loosening the clamping device. After removing the tightening device, the sleeve 20 is press-fitted to 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 carrying out a method of the present invention.
FIG. 2 is a diagram showing a state in which a slide core 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 end portions are connected by a conductor connecting element.
FIG. 6 is a diagram illustrating a state where a sleeve is fitted together with a pressing plate at a connection position of both conductor end portions.
FIG. 7 is a diagram illustrating a state in which a pressing plate is removed from a connection position of both conductor end portions and a sleeve is press-fitted.
[Explanation of symbols]
1 Stand 2 Side Guide Element 3 Side Guide Element 4 Fixing Device 5 Fixing Device 6 Guide Device 7 Tightening 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 connecting element 20 Sleeve 41 Retaining ring 51 Retaining ring 71 Pressing plate 72 Pressing plate 73 Screw rod 74 Nut 81 Spreading part of slide core

Claims (2)

Peel off the cable sheath at the ends of the two high-voltage cables to be connected to each other, peel off the exposed cable insulation partially to expose the ends of the cable cores , and elastically expand the tube made of rubber elastic material spread elastically by first action of mechanical forces the sleeve to be, the sleeve in a wide geta state, fitted on the cable end of one cable, determines the temporary position outside of the later connection position, then connect the conductors of both the cable end from one another, followed by fixing the position of the wide girder sleeve over the conductor connection position where it mechanically stress relief, the connection position of the two synthetic resin insulated high-voltage cable In the method of attaching the sleeve to the
Elastically spread apart the sleeve by applying an axial force to the sleeve by pushing this time the inner diameter of the sleeve is strong axially of the sleeve in a state that is not widened internal diameter and the diameter of the outer diameter of the cable insulation by a value corresponding to about one third of the difference spread apart, before fitting the wide clogs sleeve at one end of the cable, the wide clogs cylindrical slightly conical at the end of this one to the cable end Two slides are applied, the sleeve is fitted into the cable insulation beyond the conical end thereof, the sleeve is temporarily positioned at the one cable end, and then the slide core is removed again. A method of attaching a sleeve to the connection position of a high voltage cable. A device for expanding the sleeve, a device for holding the sleeve in an elastically expanded state, a device for shifting the expanded sleeve in the axial direction and fixing its position, and a device for relieving the stress of the sleeve. The two pressing plates that expand the sleeve (20), hold the sleeve in an elastically expanded state, and relieve the stress of the sleeve are applied to the end face side of the sleeve and tightened to each other Forming a fastening device (7) consisting of (71, 72) and being able to move in the axial direction in the gantry (1), in which case the gantry tightens one cable end (10) to The first device (4) fixed in the direction, the guide device (6) movable in the axial direction for the cable end, and the second cable end (15) are tightened to fix in the axial direction. An apparatus (5) and that the device for carrying out the method of claim 1, wherein the comprises a.

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