JP5424242B2 - Connection method and connection device - Google Patents

Description

  The present invention relates to a connection method and a connection device, and is particularly useful when applied to cables that supply power.

  In recent years, power distribution facilities have been increased in voltage and current, long-distance wide-area and high-density, or strengthened grid connection, while power distribution facilities and transformer substations that control, protect, and control power supply. In addition to responding to the increase in density and higher density, further consideration is required for cost reduction, reliability maintenance, and environmental and disaster prevention.

In the distribution of electric power, a pipeline air transmission line or a CV cable is mainly used as a high-voltage / high-current transmission line. A pipeline air transmission line includes a pipeline, a conductor disposed in the pipeline, and SF ₆ (sulfur hexafluoride) gas as an insulator that is pressurized and filled in the pipeline. Has been. Such a pipeline air transmission line uses SF ₆ gas having a high global warming potential, so that a solid insulator may be used instead of SF ₆ from the viewpoint of environmental considerations as described above. It is being considered.

  As an application example of such a solid insulator, CV cables made of a conductor and a solid insulator such as epoxy covering the conductor are electrically connected to each other, and the solid insulators are mechanically connected to each other. There is a connection structure connected so as to come into contact (for example, see Patent Document 1).

The connection structure according to Patent Document 1 can contribute to the mitigation of global warming by making SF ₆ gas unnecessary. In addition, the shape of the interface between the solid insulators is such that the cross-sectional shape in the axial direction of the conductor has a wave shape (a configuration in which the interface has an inclined surface and a folded surface inclined with respect to the axial direction of the conductor). Thus, the area of the interface for obtaining the required dielectric strength can be ensured, and a compact exclusive area can be realized to meet the demand for higher density power distribution facilities.

  However, when the CV cables are connected to each other, an air layer is formed at the interface between the insulators of the CV cables, which may cause a decrease in insulation performance. In particular, as described above, when the shape of the interface between the solid insulators is a wave shape, there is a problem that air easily accumulates in the valleys and the tops of the waves and dielectric breakdown easily occurs.

  Such a problem is not limited to the connection of CV cables, and generally exists for a connection structure in which conductors are connected and insulated by a solid insulator.

JP 2004-40989 A

  An object of the present invention is to provide a connection method and a connection device that can prevent a decrease in dielectric strength of a connection structure in which conductors are connected and insulated with a solid insulator in view of the above-described conventional technology.

In order to achieve the above object, a first aspect of the present invention includes: a first connection body having a first high voltage conductor and a first solid insulator covering the first high voltage conductor; a second high voltage conductor; A connection method for connecting a second connection body having a second solid insulator covering the second high-voltage conductor, wherein the first connection body and the second connection body are disposed in a container, After electrically connecting the first high-voltage conductor and the second high-voltage conductor and evacuating the inside of the container, the first solid insulator and the second solid insulator are brought into close contact with each other, and the inside of the container In the connection method, the second solid insulator is pressed against the first solid insulator while returning the pressure from the vacuum state to the atmospheric pressure .

In the first aspect, when the first connection body and the second connection body are connected, the first solid insulator and the second solid insulator are brought into close contact with each other in a vacuum state, so that air enters these interfaces. It is possible to prevent a decrease in dielectric strength due to this. Furthermore, when the pressure is completely returned to the atmospheric pressure and then pressed, there is a high possibility that air will enter the interface, and this can be avoided. In addition, when insulating oil is applied to the interface of the second solid insulator to the first solid insulator, the insulating oil scatters out of the interface by maintaining the vacuum state, and the interface is accompanied by the scattering. An air layer can be prevented from being formed.

  According to a second aspect of the present invention, in the connection method according to the first aspect, after the first solid insulator and the second solid insulator are brought into close contact with each other, the second solid insulator is attached to the first solid insulator. The connection method is characterized by pressing a solid insulator.

  In the second aspect, even if air enters the interface, the air can be excluded from the interface by pressing.

According to a third aspect of the present invention, in the connection method described in the first or second aspect, after applying insulating oil to the surfaces of the first solid insulator and the second solid insulator that are in close contact with each other, The connection method is characterized by close contact.

In the third aspect, air can be more reliably prevented from entering the interface between the first solid insulator and the second solid insulator.

According to a fourth aspect of the present invention, in the connection method according to any one of the first to third aspects, the interface between the first solid insulator and the second solid insulator that are in close contact is the first method. And an inclined surface that is greater than 0 degree and less than 90 degrees with respect to the axial direction of the second high-voltage conductor, and a folded portion that bends the inclined surface in the opposite direction with respect to the axial direction of the first and second high-voltage conductors. The connection method is characterized in that it is formed to have a portion.

In the fourth aspect, it is possible to prevent an air layer from being formed at the folded portion at the interface between the first solid insulator and the second solid insulator.

According to a fifth aspect of the present invention, there is provided a first connecting body having a first high voltage conductor and a first solid insulator covering the first high voltage conductor, a second high voltage conductor and the second high voltage conductor. A connection device for connecting a second connection body having a second solid insulator to be covered, the container for housing the first connection body and the second connection body, the first connection body, and the second connection body. Provided in the container is provided with support means for supporting the connection body so as to be movable in the axial direction of the first high-voltage conductor and the second high-voltage conductor, and pressure adjusting means for setting the pressure in the container. When connecting the first connection body and the second connection body, the inside of the container can be evacuated by the pressure adjusting means, and the first solid insulator and the second solid insulator can be brought into close contact with each other. The connection device is configured as described above.

In the fifth aspect, since the first solid insulator and the second solid insulator are brought into close contact with each other in a vacuum state, a connection structure between the first connector and the second connector that prevents a decrease in dielectric strength is manufactured. can do.

  ADVANTAGE OF THE INVENTION According to this invention, the connection method and connection apparatus which can prevent the fall of the dielectric strength of the connection structure which connects conductors and insulates with a solid insulator are provided.

It is a figure which shows sectional drawing of the power cable which concerns on Embodiment 1 of this invention. It is a figure which shows the procedure which connects the power cable which concerns on Embodiment 1 of this invention. It is a figure which shows sectional drawing of the power cable which concerns on Embodiment 2 of this invention. It is a photograph which shows the power cable which concerns on the Example of this invention, and the power cable which concerns on a comparative example.

<Embodiment 1>
In the connection method according to this embodiment of the present invention, as the first connection body and the second connection body, the first power cable 1 and the second connection line through which a high voltage (for example, about 66 kV to 275 kV) and a large current (for example, 1000 A or more) flow. A case where the power cable 2 is connected will be described. First, a connection structure of power cables connected by the connection method will be described.

  As shown in FIG. 1, the first power cable 1 (first connection body) includes a first high-voltage conductor 3 and a first solid insulator 5 that covers the first high-voltage conductor 3. Further, the second power cable 2 (second connection body) includes a second high voltage conductor 4 and a second solid insulator 6 that covers the second high voltage conductor 4. The opposing first high voltage conductor 3 and the second high voltage conductor 4 are electrically connected, and the opposing first solid insulator 5 and second solid insulator 6 are mechanically connected. ing.

  The first high voltage conductor 3 and the second high voltage conductor 4 have a circular cross-sectional shape, and the first solid insulator 5 and the second solid insulator 6 have the first high voltage conductor 3 and the second high voltage conductor 4. These are arranged coaxially with each of them as a center. The distal end portion of the first high voltage conductor 3 and the distal end portion of the second high voltage conductor 4 are formed so as to be fitted to each other so that they can be electrically connected satisfactorily. A ground electrode 11 such as a copper tape or a wire shield is provided on the outer peripheral surface of each of the first solid insulator 5 and the second solid insulator 6.

  Inclination in which the interface 7 between the first solid insulator 5 and the second solid insulator 6 in contact is greater than 0 degree and less than 90 degrees with respect to the axial direction of the first high voltage conductor 3 and the second high voltage conductor 4 The surface 8 and the inclined surface 8 are formed to have at least one folded portion 9 that bends in the opposite direction with respect to the axial direction of the first high-voltage conductor 3 and the second high-voltage conductor 4.

  The axial directions of the first high voltage conductor 3 and the second high voltage conductor 4 in the present embodiment are the center of the cross section of the first high voltage conductor 3 and the second high voltage conductor 4 in the vicinity of the interface 7. The direction which the line which connects with the center of the cross section of this will be formed, and it calls only an axial direction hereafter.

  The folded portion 9 formed at the interface 7 is provided so as to form a mountain or a valley in the radial direction. Moreover, it is preferable to round the top part formed by folding and to make the folding part 9 into a curved surface shape. This is because the concentration of the electric field in the folded portion 9 can be reduced by making the folded portion 9 curved. As shown in FIG. 1, one or more folding portions 9 may be provided, or only one folding portion 9 may be provided. From the viewpoint of increasing the area of the interface 7, it is preferable that the number of the folded portions 9 is one or more. For example, in the present embodiment, the connecting portion of the first solid insulator 5 and the second solid insulator 6 is made thick, and the first solid insulator 5 and the second solid conductor 5 are connected to the first high voltage conductor 3 and the second high voltage conductor 4. Five folded portions 9 are formed toward the outside of the solid insulator 6. Moreover, the inclined surface 8 and the folding | returning part 9 in this embodiment are formed so that it may become symmetrical about an axial direction.

  In the present embodiment, the conductive material 10 is disposed in the vicinity of the folded portion 9. The conductive material 10 serves to alleviate the electric field concentration at the folded portion 9 and make the electric field distribution at the interface 7 more uniform. In the present embodiment, a copper ring is arranged as the conductive material 10 at a position facing the apex of the folded portion 9 provided symmetrically with respect to the axial direction.

  Here, the process of connecting these power cables with the connecting device that connects the first power cable 1 and the second power cable 2 will be described with reference to FIG.

  As shown in FIG. 2A, the connecting device has a container 20 that houses the first power cable 1 and the second power cable 2. In the present embodiment, the container 20 includes a first container part 21 and a second container part 22 configured to be detachable from the first container part 21, and the first container part 21 and the second container part 22 are engaged with each other. A storage portion 25 is formed in the interior.

  Each of the first container portion 21 and the second container portion 22 is provided with a support portion 23 that supports the first power cable 1 and the second power cable 2. The support part 23 has an insertion hole 23a through which the first power cable 1 and the second power cable 2 are inserted, and the first power cable 1 and the second power cable 2 are movable in the axial direction. . Moreover, the support part 23 has a seal structure (not shown in particular), and when the first power cable 1 and the second power cable 2 are inserted through the insertion hole 23a, the storage part 25 is kept airtight. It is supposed to be. For example, the sealing structure can be configured by providing an O-ring in contact with the outer peripheral surfaces of the first power cable 1 and the second power cable 2 in the insertion hole 23a.

  A vacuum pump 24 is connected to the container 20 as an example of a pressure adjusting means for setting the atmospheric pressure therein. The vacuum pump 24 is not particularly limited as long as the inside of the container 20 can be set to a pressure of, for example, atmospheric pressure to 1 Pa.

  Using such a connection device, first, the first power cable 1 is supported by the support portion 23 of the first container portion 21 so that the distal end side of the first power cable 1 is positioned on the side that becomes the storage portion 25. Similarly, the second power cable 2 is supported by the support portion 23 of the second container portion 22 so that the distal end side of the second power cable 2 is positioned on the side that becomes the storage portion 25. At this time, high-viscosity insulating oil such as silicone oil is applied to the interface 7 between the first solid insulator 5 and the second solid insulator 6 that are in contact with each other. Then, as shown to Fig.2 (a), the 1st container part 21 and the 2nd container part 22 are engaged. In this state, the first power cable 1 and the second power cable 2 are not brought into contact with each other, and the air pressure in the storage unit 25 is set to atmospheric pressure.

  Next, as shown in FIG. 2B, the first power cable 1 and the second power cable 2 are brought close to each other, and the first high voltage conductor 3 and the second high voltage conductor 4 are fitted. At this time, the first solid insulator 5 and the second solid insulator 6 are prevented from contacting each other. In the present embodiment, the first high-voltage conductor 3 and the second high-voltage conductor 4 are not completely fitted, and a margin that allows further push-fitting is left behind. Note that the pressure in the storage portion 25 is particularly limited from the state shown in FIG. 2A until the first high-voltage conductor 3 and the second high-voltage conductor 4 are fitted (FIG. 2B). There may be no atmospheric pressure or a vacuum state.

  Next, as shown in FIG. 2C, the vacuum pump 24 is operated to make the pressure in the storage unit 25 vacuum. When the pressure in the storage section 25 becomes a vacuum, the first power cable 1 and the second power cable 2 are pressed against each other to bring the first solid insulator 5 and the second solid insulator 6 into close contact with each other.

  In this way, by bringing the first solid insulator 5 and the second solid insulator 6 into close contact with each other under a vacuum state, air is prevented from being taken into the interface 7, and the dielectric strength is reduced by the air. Can be prevented. In addition, since the insulating oil is applied to these interfaces 7, it is possible to eliminate room for air to enter, and thus it is possible to further prevent a decrease in the dielectric strength.

  In particular, as in the present embodiment, when the shape of the interface 7 is not flat like the shape formed by the inclined surface 8 and the folded portion 9, air tends to accumulate in the folded portion 9 and the like. However, in the connection method according to the present embodiment, even when such non-planar insulators are connected to each other, it is possible to prevent air from entering the interface 7.

  Further, after the first solid insulator 5 and the second solid insulator 6 are brought into close contact with each other, the first power cable 1 is pressed against the second power cable 2. Even if air enters the interface 7 by such pressing, the air can be excluded from the interface 7 by pressing.

  Further, the pressing of the first power cable 1 and the second power cable 2 after the close contact is performed while the pressure in the storage unit 25 is set to atmospheric pressure. When the pressure is fully returned to the atmospheric pressure, there is a high possibility that air will enter the interface 7. This can be avoided, and the insulating oil is scattered outside the interface 7 by maintaining the vacuum state. And it can prevent that an air layer is formed in the interface 7 with the scattering.

  Thereafter, although not particularly illustrated, the container 20 is removed, and the first cable 1 and the second cable 2 are mechanically connected so that the first cable 1 and the second cable 2 are maintained in a joined state. Fix it.

  As described above, according to the connection method and the connection device according to the first embodiment, in the vacuum state, the first solid insulator 5 and the second solid insulator of the first power cable 1 and the second power cable 2 are used. 6 can be provided, so that it is possible to provide a power cable connection structure that prevents a decrease in dielectric strength due to air entering these interfaces 7.

<Embodiment 2>
In the first embodiment, the interface between the first solid insulator and the second solid insulator is curved, but it may be a planar interface. Moreover, although the case where they are directly adhered has been described, they may be adhered via another insulator.

  FIG. 3 is a cross-sectional view of the power cable according to the second embodiment. The cable conductor tip portions 102 of the first and second power cables 101 to be connected are arranged to face each other, and are electrically connected by being compressed into the conductor connection tube 111 after being fitted into the conductor connection tube 111. A cylindrical epoxy unit 112 as an insulator is disposed around the conductor connection tube 111. At both ends of the epoxy unit 112, truncated cone-shaped pre-mold insulators 113a and 113b (first solid insulator and second solid insulator) are arranged. The pre-mold insulators 113a and 113b are pressed so as to be in close contact with the epoxy unit 112 and the first and second power cables 101 by a compression device 114 configured using a spring.

  Thus, the premold insulators 113a and 113b are connected via the epoxy unit 112. According to the connection method of the present invention, for example, the epoxy unit 112 is fixed in the container 20, and the storage unit 25 of the container 20 is evacuated, and then the premolded insulators 113 a and 113 b are brought into close contact with the epoxy unit 112. Thus, it is possible to prevent air from entering these interfaces 115.

<Example>
FIG. 4 is a photograph showing a power cable according to an example of the present invention and a power cable according to a comparative example.

  As shown, the power cable A is formed by the connection method according to the present invention, and the power cable B is formed by the conventional connection method, that is, under atmospheric pressure. In the power cable A, an air layer is not formed at the interface portion between the silicone rubber portion (first solid insulator) and the epoxy resin portion (second solid insulator). On the other hand, an air layer is formed on the interface portion of the power cable B in a crescent shape. Thus, although the conventional connection method forms an air layer that can be sufficiently recognized visually, the formation of such an air layer is prevented in the connection method of the present invention.

<Other embodiments>
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

  The first connection body or the second connection body according to the present invention is not limited to the connection between power cables, and includes at least a high-voltage conductor and a solid insulator covering the high-voltage conductor. The form is not particularly limited. As the first connection body or the second connected body, for example, a power cable or a power device (for example, a circuit breaker or a disconnecting switch) used in a substation facility is applicable. Therefore, the connection method according to the present invention can be applied to a connection between a power cable and a power device or a connection between power devices.

  Moreover, in Embodiment 1, although the insulating oil was apply | coated to the 1st solid insulator 5 and the 2nd solid insulator 6, it is not essential. In addition, after the storage portion 25 is evacuated, the first solid insulator 5 and the second solid insulator 6 are brought into close contact with each other, but it is not always necessary to press or press while maintaining the atmospheric pressure. Alternatively, it may be fixed in close contact under vacuum.

  The present invention can be used in an industrial field where it is necessary to connect a power cable or a power device.

A power cable B power cable 1 first power cable 2 second power cable 3 first high voltage conductor 4 second high voltage conductor 5 first solid insulator 6 second solid insulator 7, 115 interface 8 inclined surface 9 folded portion DESCRIPTION OF SYMBOLS 10 Conductive material 11 Ground electrode 20 Container 21 1st container part 22 2nd container part 23 Support part 23a Insertion hole 24 Vacuum pump 25 Storage part 101 1st power cable 101 2nd power cable 102 Cable conductor front-end | tip part 111 Conductor connection pipe 112 Epoxy unit 113a, 113b Premold insulator 114 Compression device

Claims (5)

A first connecting body having a first high-voltage conductor and a first solid insulator covering the first high-voltage conductor; and a second high-voltage conductor and a second solid insulator covering the second high-voltage conductor. A connection method for connecting the second connection body,
Arranging the first connector and the second connector in a container;
Electrically connecting the first high voltage conductor and the second high voltage conductor;
After evacuating the container, the first solid insulator and the second solid insulator are closely attached ,
A connection method , wherein the second solid insulator is pressed against the first solid insulator while returning the inside of the container from a vacuum state to an atmospheric pressure . The connection method according to claim 1,
A connection method comprising pressing the second solid insulator against the first solid insulator after the first solid insulator and the second solid insulator are brought into close contact with each other. In the connection method according to claim 1 or 2 ,
A connection method comprising: applying insulating oil to surfaces of the first solid insulator and the second solid insulator that are in close contact with each other, and then bringing them into close contact with each other. In the connection method according to any one of claims 1 to 3 ,
The interface between the first solid insulator and the second solid insulator that are in close contact with each other is an inclined surface that is greater than 0 degree and less than 90 degrees with respect to the axial direction of the first and second high voltage conductors; A connection method comprising: a folded portion that bends the inclined surface in the opposite direction with respect to the axial direction of the first and second high-voltage conductors. A first connecting body having a first high-voltage conductor and a first solid insulator covering the first high-voltage conductor; and a second high-voltage conductor and a second solid insulator covering the second high-voltage conductor. A connection device for connecting the second connection body,
A container for housing the first connector and the second connector;
Support means for supporting the first connection body and the second connection body movably in the axial direction of the first high-voltage conductor and the second high-voltage conductor;
Pressure adjusting means for setting the atmospheric pressure in the container,
When connecting the first connector and the second connector disposed in the container, the container is evacuated by the pressure adjusting means, and the first solid insulator and the second solid insulator are evacuated. A connection device, characterized in that it can be brought into close contact with a body.