JP6789882B2 - Cable head of gas insulation switchgear - Google Patents

Description

An embodiment of the present invention relates to a cable head of a gas-insulated switchgear.

In electric power facilities that handle high-voltage power such as substations and power plants, gas-insulated switchgear with excellent safety, maintainability, etc. is often used as a switchgear for electric power. The gas-insulated switchgear is equipped with a cable head at the connection of an external power cable.

In the cable head, the conductor on the tank side of the device body and the conductor of the external power cable are drawn into the inside of the head case connected to the tank of the device body. Inside the head case, the cable cone (stress cone) for insulation that covers the circumference of the conductor of the power cable, the conductor of the power cable protruding upward from the cable cone, and the conductor on the tank side of the main body of the device are placed on the upper side of the cable cone. It houses a fitting that connects electrically. Further, in the head case, a shielding member is arranged so as to cover the area above the connector and the area extending from the side outer peripheral area of the connector to the side outer peripheral area of the cable cone. The lower edge of the shielding member is in a non-contact state with respect to the outer peripheral surface of the cable cone.
The cable cone suppresses the distribution of the electric field from being disturbed by the conductors and connectors in the head case, thereby improving the withstand voltage characteristics. The shielding member also relaxes the electric field concentration between the connector and the cable cone.

Since the withstand voltage characteristic of this type of cable head deteriorates when foreign matter such as metal powder remains inside, the foreign matter is removed and cleaned after the assembly of the internal parts is completed. However, even after the removal and cleaning of foreign matter is completed in the cable head, new foreign matter such as metal powder may be generated inside due to rattling or the like accompanying the movement of the device.

In addition, conductors such as power cables are usually tin-plated or zinc-plated for the purpose of ensuring energization performance and preventing the formation of an oxide film. In this case, whiskers, which are needle-shaped metal crystals, naturally occur on the metal surface of the conductor due to long-term use, and the whiskers may float in the head case.

Foreign substances such as metal powder and whiskers generated in the cable head fall to the outer surface of the cable cone or the bottom surface inside the head case due to vibration caused by electromagnetic force acting on the energizing path or vibration caused by an earthquake, and the withstand voltage at the cable head. There is concern that the characteristics will be reduced.

Utility Model Registration No. 3203676

An object to be solved by the present invention is to provide a cable head of a gas-insulated switchgear capable of preventing foreign matter from falling onto the outer surface of a cable cone or the bottom surface of a head case.

The cable head of the gas-insulated switchgear of the embodiment includes a head case, a cable cone for insulation, a connector, a shielding member, and a cover member. In the head case, the conductor on the tank side of the main body of the device and the conductor of the external power cable are drawn inside. The cable cone wraps around the conductor of the power cable that is pulled into the head case. The connector electrically connects the conductor of the power cable and the conductor on the tank side of the device body on the upper side of the cable cone. The shielding member covers the area above the connector and from the side outer peripheral area of the connector to the side outer peripheral area of the cable cone to alleviate the electric field concentration between the connector and the cable cone. The cover member covers the side peripheral area and the lower side of the connector on the upper side of the cable cone.

The cross-sectional view which shows the gas insulation switchgear of 1st Embodiment. FIG. 2 is a cross-sectional view of the cable head of the first embodiment along line II-II of FIG. FIG. 2 is a cross-sectional view taken along the line III-III of FIG. 2 of the cable head of the first embodiment. FIG. 5 is a cross-sectional view taken along the line IV-IV of FIG. 5 of the cable head of the first modification of the embodiment. FIG. 4 is a cross-sectional view taken along the line VV of FIG. 4 of a cable head of a modified example of the first embodiment. FIG. 7 is a cross-sectional view taken along the line VI-VI of FIG. 7 of the cable head of another modification of the first embodiment. FIG. 6 is a cross-sectional view of a cable head of another modification of the first embodiment along line VII-VII of FIG. FIG. 2 is a cross-sectional view similar to FIG. 2 of the cable head of the second embodiment. FIG. 2 is a cross-sectional view similar to FIG. 2 of the cable head of the third embodiment.

Hereinafter, the cable head of the gas-insulated switchgear of the embodiment will be described with reference to the drawings. In the following description, the same reference numerals are given to configurations having the same or similar functions. Then, the duplicate description of those configurations may be omitted.

(First Embodiment)
First, the cable head of the gas-insulated switchgear of the first embodiment will be described with reference to FIGS. 1 to 7.
FIG. 1 is a schematic cross-sectional view of a part of a gas-insulated switchgear 1 that employs the cable head 10 of the present embodiment. FIG. 2 is a cross-sectional view of the cable head 10 along the line II-II of FIG. 3, and FIG. 3 is a cross-sectional view of the cable head 10 along the line III-III of FIG.
Although detailed illustration is omitted, the gas-insulated switchgear 1 is a gas-insulated circuit breaker having an arc-extinguishing chamber inside, and a disconnector unit connected to the upstream side and the downstream side of the gas-insulated circuit breaker in the power transmission direction. Is equipped with. The disconnector unit includes a disconnector for separating electric circuits, a current transformer for measurement, a grounding switch for work, a bus, and the like. In the gas insulation circuit breaker and disconnector unit, an insulating gas such as SF ₆ (sulfur hexafluoride) gas is sealed inside the device main body tank.

The cable head 10 is connected to the device main body tank 2 of the disconnector unit, for example, as shown in FIG. A conductor 3 is arranged in the apparatus main body tank 2. The conductor 3 is held at the end of the apparatus main body tank 2 via the insulating spacer 6. The cable head 10 has a conductor 3 on the side of the main body tank 2 of the apparatus and a head case 11 into which the conductor 5 of the external power cable 4 is drawn. The upper side surface of the head case 11 is connected to the apparatus main body tank 2, and the conductor 5 of the power cable 4 is drawn in from below the bottom wall 11a. In addition, an insulating gas such as SF ₆ (sulfur hexafluoride) gas is sealed inside the head case 11.

On the bottom wall 11a of the head case 11, an insulating cable cone 12 that covers the periphery of the conductor 5 of the power cable 4 is installed. The cable cone 12 is formed in a substantially conical shape whose outer diameter gradually narrows toward the upper side, and its upper end is formed flat. The conductor 5 of the power cable 4 penetrates the axial center of the cable cone 12 and projects upward. Above the cable cone 12, a connector 13 for electrically connecting the conductor 5 protruding upward from the cable cone 12 and the conductor 3 on the device main body tank 2 side is arranged.

As shown in FIG. 2, on the flat upper surface of the cable cone 12, a connector 13 and a shielding block 15 that covers the periphery of the connector 13 are installed via an arbitrary number of spacer rings 14. The conductor 5 of the power cable 4 is inserted from below through the through hole 14a in the center of each spacer ring 14.

The shielding block 15 includes a thick-walled cylindrical first shielding member 16 that holds the upper portion of the connector 13, peripheral covers 17A and 17B and a bottom plate 18 that cover the outer peripheral region and the lower side of the connector 13, and a first plate. It is provided with a peripheral area covers 17A and 17B attached to the shielding member 16 and a thin-walled cylindrical second shielding member 19 that surrounds the outside of the bottom plate 18. The lower edge portion of the second shielding member 19 extends to the vicinity of the tapered outer peripheral surface of the cable cone 12. A gap d is secured between the second shielding member 19 and the outer peripheral surface of the cable cone 12. The first shielding member 16 and the second shielding member 19 are formed of a metal material having a large electric resistance such as an aluminum alloy. Further, the peripheral covers 17A and 17B and the bottom plate 18 are also formed of a metal material having a large electric resistance such as an aluminum alloy, like the first shielding member 16 and the second shielding member 19.
The first shielding member 16 and the second shielding member 19 constitute a shielding member that relaxes the electric field concentration between the connector 13 and the cable cone 12 when a voltage is applied. Further, the peripheral area covers 17A and 17B and the bottom plate 18 form a cover member that covers the outer peripheral area and the lower side of the connector 13 on the upper side of the cable cone 12.

The connector 13 includes a connector body 13A attached to the first shielding member 16 and a holding piece 13B attached to the connector body 13A and sandwiching the conductor 5 on the power cable 4 side together with the connector body 13A. ing. The connector main body 13A and the holding piece 13B are formed of a highly conductive metal material and are electrically connected to the conductor 5 on the power cable 4 side.

The connector main body 13A includes a perforated disc-shaped mounting base 21 that is fastened and fixed to the lower surface of the first shielding member 16 by bolts 20, a boss portion 22 that protrudes from the upper surface side of the mounting base 21, and a mounting base. An arm piece 23 extending downward from the lower surface side of the arm piece 21 and a holding piece 24 connected to the lower end of the arm piece 23 are provided. As shown in FIG. 3, the holding piece 24 of the connector main body 13A is formed in a substantially symmetrical shape with the holding piece 13B. Both holding pieces 24 and 13B have a substantially arc-shaped holding portion 25 that holds the outer peripheral surface of the conductor 5 on the power cable 4 side, and a pair of fastening flanges 26 that extend in opposite directions from both ends of the arc of the holding portion 25. And have. In the sandwiching pieces 24 and 13B, the fastening flanges 26 facing each other are fastened and fixed by bolts 27 in a state where the conductor 5 is interposed between the sandwiching portions 25. As a result, the connector 13 is electrically connected to the conductor 5 on the power cable 4 side.

The first shielding member 16 has a conductor insertion hole 28 formed in the center on the upper surface side. Further, a substantially circular recess 29 communicating with the conductor insertion hole 28 is formed in the center of the lower surface side of the first shielding member. The boss portion 22 of the connector main body 13A is fitted into the lower region of the recess 29 from below. In the space surrounded by the recess 29 and the boss portion 22, a plurality of connecting claws 30 formed of conductive metal and an urging spring 31 for urging the connecting claws 30 inward in the radial direction of the recess 29 are housed. Has been done. The base end portion (lower end portion) of the plurality of connecting claws 30 is contact-connected to the boss portion 22 of the connector main body 13A. The end of the conductor 3 on the device main body tank 2 side is inserted into the conductor insertion hole 28 of the first shielding member 16 from above. At this time, the end of the conductor 3 is inserted into the connecting claw 30 against the urging force of the urging spring 31, so that the connecting tool 13 is placed on the device main body tank 2 side via the plurality of connecting claws 30. It is electrically connected to the conductor 3.

Further, a connecting flange 32 extends from the outer periphery of the lower end of the first shielding member 16. An inward flange 33 extending from the upper end of the second shielding member 19 is fastened and fixed to the connecting flange 32 by bolts 34.

The bottom plate 18 is formed in the shape of a perforated disc, and the conductor 5 of the power cable 4 is inserted into the central through hole 18a from below. A pair of brackets 35 having a substantially L-shaped side view are attached to the upper surface of the bottom plate 18. One side of each bracket 35 is fixed to the bottom plate 18 by bolts 36a and nuts 36b, and the holding piece 24 of the connector main body 13A is fastened and fixed to the other side by bolts 27. As a result, the connector 13 is fixed to the upper surface side of the bottom plate 18.

Further, in each of the peripheral area covers 17A and 17B, a joint flange 37b extends at the end of the semi-cylindrical main wall 37a surrounding the side outer peripheral area of the connector 13 in the arc direction. The pair of peripheral covers 17A and 17B have joint flanges 37b butted against each other, and the joint flanges 37b are fastened and fixed to each other by bolts 38a and nuts 38b. Further, a flange portion 37c bent outward in the radial direction extends from the lower end of the main wall 37a of each peripheral area cover 17A and 17B. The flange portions 37c of the peripheral cover 17A and 17B are abutted against the upper surface of the bottom plate 18, and are fastened and fixed to the bottom plate 18 by bolts 39a and nuts 39b.

In this way, the shielding block 15 to which the bottom plate 18 and the peripheral covers 17A and 17B are assembled is placed in a state where the lower surface of the inner peripheral edge portion of the bottom plate 18 is in contact with the upper surface of the uppermost spacer ring 14. As a result, the peripheral peripheral area and the lower side of the connector 13 are closed by the peripheral area covers 17A and 17B and the bottom plate 18. Therefore, even if metal powder is generated in the connector 13 or its vicinity or whiskers are naturally generated on the metal surface of the conductor 5 after the parts are assembled in the cable head 10, these foreign substances are still present. The cable cone 12 does not fall onto the outer peripheral surface of the cable cone 12 or the bottom wall 11a in the head case 11 through the gap d below the second shielding member 19.

As described above, the cable head 10 of the present embodiment includes peripheral area covers 17A and 17B and a bottom plate 18 that cover the outer peripheral area and the lower side of the connector 13 on the upper side of the cable cone 12. Therefore, even if metal powder is generated in the connector 13 or its vicinity or whiskers are naturally generated on the metal surface of the conductor 5, these foreign substances fill the gap d below the second shielding member 19. It is possible to prevent the cable cone 12 from falling onto the outer peripheral surface of the cable cone 12 or the bottom wall 11a in the head case 11. Therefore, it is possible to suppress deterioration of the withstand voltage characteristic of the cable head 10 due to foreign matter adhering to the outer peripheral surface of the cable cone 12 or the bottom wall 11a in the head case 11.

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 5 of a modified example of the cable head 10 of the first embodiment, and FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4 of the modified example. It is a figure.
In the cable head 10 of this modification, the bag nuts 38bA, 39bA, 27bA, which are nuts to be penetrated, are attached to the fastening portions of the members of the peripheral covers 17A and 17B and the bottom plate 18 and the fastening portions of the internal members to each other. , 36bA is adopted. Specifically, the fastening portion between the peripheral covers 17A and 17B, the fastening portion between the peripheral covers 17A and 17B and the bottom plate 18, the fastening portion between the holding piece 24 and the holding piece 13B of the connector 13, and the bracket 35. The bag nuts 38bA, 39bA, 27bA, and 36bA are used for the fastening portion of the bottom plate 18. The bag nuts 38bA, 39bA, 27bA, and 36bA are welded and fixed to a member having a bolt insertion hole.

In the cable head 10 of this modified example, bag nuts 38bA, 39bA, 27bA, 36bA are adopted for the fastening portions of the members of the peripheral covers 17A and 17B and the bottom plate 18 and the fastening portions of these internal members. Therefore, it is possible to prevent the metal powder generated by tightening each bolt from falling to the outside from the tightened portion of the bolt and nut. Therefore, by adopting this configuration, it is possible to more reliably prevent the metal powder from adhering to the outer peripheral surface of the cable cone 12 and the bottom wall 11a in the head case 11 and deteriorating the withstand voltage characteristics. ..

FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 7 of another modification of the cable head 10 of the first embodiment, and FIG. 7 is taken along the line VII-VII of FIG. 6 of the same modification. It is a sectional view.
In the cable head 10 of this modified example, a sealing member 40 such as a rubber plate or resin is interposed between the abutting portions of the members of the peripheral covers 17A and 17B and the bottom plate 18 and the abutting portions of the internal members. There is. Specifically, for example, between the joint flanges 37b of the peripheral covers 17A and 17B, between the flanges 37c of the peripheral covers 17A and 17B and the upper surface of the bottom plate 18, the holding piece 24 and the holding piece 13B of the connector 13. A sealing member 40 is interposed between the upper ends of the peripheral covers 17A and 17B and the lower surface of the first shielding member 16.

In the cable head 10 of this modified example, since the sealing member 40 is interposed at the abutting portion of a plurality of members arranged above the cable cone 12, foreign matter such as metal powder is present between or inside these members. Even if it may remain, it is possible to more reliably prevent foreign matter from falling on the outer peripheral surface of the cable cone 12 or on the bottom wall 11a in the head case 11.

(Second Embodiment)
Next, the cable head 110 of the second embodiment will be described with reference to FIG.
The basic configuration of the cable head 110 of the present embodiment is substantially the same as that of the first embodiment, but the peripheral area cover 117 forming a part of the cover member is configured as an integral body with the first shielding member 116. ing. The peripheral area cover 117 is formed in a cylindrical shape, and the upper end portion thereof is continuously provided on the lower surface of the outer peripheral portion of the first shielding member 116. In the case of the present embodiment, since the peripheral area cover 117 is formed to be thick integrally with the first shielding member 116, the bottom plate 18 is fastened and fixed to the lower surface of the peripheral area cover 117 by a plurality of screws 41.

In the cable head 110 of the present embodiment, since the peripheral area cover 117 forming a part of the cover member is configured as an integral body with the first shielding member 116, the same effect as that of the first embodiment can be obtained. , It is possible to reduce the number of parts and suppress the rise in product cost.

(Third Embodiment)
Subsequently, the cable head 210 of the third embodiment will be described with reference to FIG.
The cable head 210 of the present embodiment has a cover member (peripheral region covers 17A, 17B and bottom plate 18 of the first embodiment) covering the outer peripheral region and the lower side of the connector 13 on the upper side of the cable cone 12. Instead of providing, the following structure is adopted.
That is, the cable head 210 of the present embodiment is provided with an annular covering member 50 that covers the side peripheral region of the connector 13 and extends to the upper end surface of the cable cone 12. The annular covering member 50 can be made of, for example, a heat-shrinkable tube, a soft resin tape, or the like. In the case of the present embodiment, the upper edge portion of the annular covering member 50 is adhered around the annular portion 49 on the lower surface of the mounting base portion 21 of the connector 13, and the lower edge portion of the annular covering member 50 is the spacer ring 14. It is adhered to the outer peripheral surface. Therefore, the periphery of the connector 13 and the spacer ring 14 is continuously substantially sealed by the annular covering member 50.

The cable head 210 of the present embodiment is provided with an annular covering member 50 that covers the side peripheral region of the connector 13 and extends to the upper end surface of the cable cone 12. Therefore, even if metal powder is generated in the connector 13 or its vicinity or whiskers are naturally generated on the metal surface of the conductor 5, these foreign substances are present on the outer peripheral surface of the cable cone 12 or in the head case 11. It is possible to prevent the metal from falling onto the bottom wall 11a of the corn. Therefore, also in the case of the present embodiment, it is possible to suppress deterioration of the withstand voltage characteristic of the cable head 210 due to foreign matter.

According to at least one embodiment described above, the outer surface of the cable cone is provided by having the head case, the cable cone for insulation, the connector, the shielding member, the cover member, or the annular covering member. It is possible to prevent foreign matter from falling onto the bottom surface of the head case.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, as well as in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... gas-insulated switchgear, 2 ... device body tank, 3 ... conductor, 4 ... power cable, 5 ... conductor, 10,110,210 ... cable head, 11 ... head case, 12 ... cable cone, 13 ... connector, 16,116 ... 1st shielding member (shielding member), 17A, 17B, 117 ... Circumferential area cover (cover), 18 ... Bottom plate (cover member), 19 ... Second shielding member (shielding member), 27bA, 36bA, 38bA , 39bA ... bag nut (non-penetrating nut), 40 ... sealing member, 50 ... annular covering member.

Claims (5)

A head case in which the conductor on the tank side of the device body and the conductor of the external power cable are drawn inside,
An insulating cable cone that surrounds the conductor of the power cable that is pulled into the head case.
A connector for electrically connecting the conductor of the power cable protruding upward from the cable cone and the conductor on the tank side of the apparatus main body on the upper side of the cable cone.
A shielding member that covers the area above the connector and from the side outer peripheral area of the connector to the side outer peripheral area of the cable cone to alleviate the electric field concentration between the connector and the cable cone.
A cover member that covers the outer peripheral region of the side portion and the lower side of the connector on the upper side of the cable cone.
The cable head of the gas-insulated switchgear equipped with. The cable head of the gas-insulated switchgear according to claim 1, wherein at least a part of the fastening portions of the members arranged on the upper side of the outer surface of the cable cone have a non-penetrating nut. The gas-insulated switchgear according to claim 1 or 2, wherein a sealing member that seals between the abutting portions is interposed at a butting portion of a plurality of members arranged on the upper side of the outer surface of the cable cone. Cable head. The cable head of the gas-insulated switchgear according to any one of claims 1 to 3, wherein at least a part of the cover member is integrally formed with at least a part of the shielding member. A head case in which the conductor on the tank side of the device body and the conductor of the external power cable are drawn inside,
An insulating cable cone that surrounds the conductor of the power cable that is pulled into the head case.
A connector for electrically connecting the conductor of the power cable protruding upward from the cable cone and the conductor on the tank side of the apparatus main body on the upper side of the cable cone.
A shielding member that covers the area above the connector and from the side outer peripheral area of the connector to the side outer peripheral area of the cable cone to alleviate the electric field concentration between the connector and the cable cone.
An annular covering member that covers the side peripheral area of the connector and extends to the upper surface of the cable cone.
The cable head of the gas-insulated switchgear equipped with.

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