JP2017208467A - Gas insulation type on-load tap switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a pressure resistance of a gas insulation type on-load tap switching device by preventing a local electric field concentration.SOLUTION: A gas insulation type on-load tap switching device 2 includes: a gas container 2c in which an opening part is formed in an upper end part, a switching circuit breaker 2a is arrange, and an insulation gas is sealed; a head part lid 6 that is fitted to the opening part of the gas container 2c; a sealing member 8 that seals between the gas container 2c and the head part lid 6; a seal pressing ring 7 that is a seal pressing member for pressing a seal member 8; an inner part sealed member 14 that cover a lower end part of the seal pressing ring 7 and provides a curve surface part 14b at a lower side; and a supporting insulation plate 22 that is attached to an external part of the switching circuit breaker 2a, of which the upper end part is arranged adjacent to the inner sealed member 14, and in which a notch 22a forming a predetermined space of the curve surface parts 14 of the inner part sealed member 14 is provided.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a gas-insulated on-load tap switching device.

  In recent years, substations installed in central Tokyo are becoming more compact and are shifting to underground types due to the difficulty of large-scale operation on the ground. Along with the transition to underground substations, gas-insulated transformers in which an insulating gas is sealed in a hermetically sealed container have become mainstream as transformers arranged in substations. This is because the gas-insulated transformer is excellent in environmental performance and safety.

Normally, a transformer connected to the grid incorporates an on-load tap switching device to stabilize the system voltage, but in response to the transformer becoming a gas insulation system, a gas insulated load An hour tap switching device is employed. In the gas-insulated load tap changer, a gas container having a hermetically sealed structure is attached to the opening of the transformer tank, and a switching switch is accommodated in the gas container. Further, a tap selector is disposed below the gas container and is connected to the transformer side via a tap lead wire.

JP 2013-247170 A

  The gas-insulated on-load tap switching device needs to isolate the switching switch from the transformer tank and maintain airtightness and insulation inside the switching switch. Therefore, the gas container is formed of a cylinder made of an insulating material, and the gas container and the head cover are sealed by a ring-shaped sealing member. And the shield is installed so that this seal | sticker may be covered. The shield has a curved surface portion so as to cover the seal member, and this shield alleviates electric field concentration inside the switching switch.

  In recent years, the gas-insulated on-load tap switching device has a tendency to increase in size due to a demand for a larger capacity. In a large-sized apparatus, in order to position and insert the switching switch into the gas container with high accuracy, a support insulating plate extending to the upper part of the gas container is attached to the outer periphery of the switching switch. However, the size of the device tends to increase the size of components inside the device. As a result, the gap between the support insulating plate and the shield becomes extremely small and local electric field concentration occurs, making it difficult to improve the pressure resistance.

  Embodiments of the present invention have been proposed to solve the above problems, and provide a gas-insulated on-load tap switching device that prevents local electric field concentration and has improved pressure resistance. Objective.

  In order to achieve the above object, a gas-insulated on-load tap switching device according to an embodiment of the present invention has a gas container in which an opening is formed at the upper end, a switching switch is disposed inside, and an insulating gas is sealed therein. A head cover that fits into the opening of the gas container, a seal member that seals between the gas container and the head cover, a seal press member that presses the seal member, and a seal press member An inner shield member having a curved surface portion covering a lower end portion, and an outer peripheral portion of the switching switch, the upper end portion being disposed adjacent to the inner shield member, and a predetermined space between the inner shield member and the curved surface portion of the inner shield member And a support insulating plate provided with a notch for forming a gap.

It is sectional drawing which shows the whole structure of the tap switch apparatus at the time of a gas insulation type load concerning 1st Embodiment. It is a partial cross section perspective view of a switching switch. It is an expanded sectional view of the A section of FIG. (A) is sectional drawing which shows the equipotential line of a prior art example, (b) is an enlarged view of the B section of (a). It is sectional drawing which shows the equipotential line of 1st Embodiment. It is a fragmentary sectional perspective view of the switching switch of the gas insulation type tap change apparatus at the time of a load concerning a 2nd embodiment. It is sectional drawing which shows the equipotential line of 2nd Embodiment. It is a fragmentary sectional perspective view of the switching switch of the gas insulation type tap change apparatus at the time of a load concerning a 3rd embodiment. It is sectional drawing which shows the equipotential line of 3rd Embodiment. It is sectional drawing which shows the structure of the tap switching apparatus at the time of a gas insulation type load concerning 4th Embodiment. It is an expanded sectional view of the C section of FIG. It is the elements on larger scale of the tap change apparatus at the time of gas insulation type load concerning a 5th embodiment. It is the elements on larger scale of the tap change apparatus at the time of gas insulation type load concerning a 5th embodiment. It is a partial cross section perspective view of the switching switch of the gas insulation type tap change apparatus at the time of a load concerning a 6th embodiment. It is sectional drawing which shows the equipotential line of 6th Embodiment.

(First embodiment)
(Constitution)
A gas-insulated on-load tap switching device according to a first embodiment will be described with reference to FIGS. As shown in FIG. 1, a gas container 2 c is attached to an opening portion of a transformer tank 1 in which an insulating gas 3 is sealed inside the gas-insulated load tap switching device 2. The gas container 2c is a cylindrical member made of an insulating material and having an opening at the upper end. A switching switch 2a is disposed inside the gas container 2c, and an insulating gas 4 for insulating and cooling the switching switch 2a is enclosed. As the insulating gas 4, for example, SF ₆ gas which is excellent in insulating performance and is a nonflammable and stable gas is used.

  A tap selector 2b that selects a pair of tap positions is disposed below the gas container 2c. A tap lead wire corresponding to each tap potential is drawn from a winding of a transformer (not shown) and joined to the tap selector 2b, whereby circuit connection between the transformer and the on-load tap switching device 2 is performed.

  A head cover 6 is fitted into the opening at the top of the gas container 2c. The head cover 6 is a member for isolating the switching switch 2 a from the transformer tank 1. The head lid 6 is made of a metal material having a cylindrical portion extending downward, and the cylindrical portion of the head lid 6 is fitted into the opening in the upper part of the gas container 2c.

  As shown in FIG. 3, a seal member 8 is disposed between the gas container 2 c and the head cover 6, and the seal member 8 is pressed against the lower end surface of the cylindrical portion of the head cover 6. A presser ring 7 is installed. The seal retainer ring 7 is joined to the lower end surface of the cylindrical portion of the head cover 6 by a bolt 7a.

  Moreover, the tube-shaped 1st external shield member 11 with a circular cross section is attached to the outer peripheral part of the gas container 2c horizontally along the outer periphery of the gas container 2c. The first external shield member 11 is a member that is not electrically connected to the head cover 6 and is provided to alleviate electric field concentration outside the switching switch 2a. Below the first outer shield member 11, a tube-shaped second outer shield member 15 having a substantially elliptical cross section is horizontally attached along the outer periphery of the gas container 2c. The second outer shield member 15 is electrically connected to a high voltage application unit (not shown).

  As shown in FIG.1 and FIG.2, the insulating cylinder 13 is arrange | positioned coaxially with the gas container 2c above the inside of the gas container 2c. An energy storage device 20 is disposed in the lower part inside the insulating cylinder 13. The energy storage device 20 is connected to a drive shaft 21 extending through the inner center of the gas container 2c. The drive shaft 21 is connected to the switching switch 2a and is switched by torque transmitted from the energy storage device 20 via the drive shaft 21. The switch 2a is driven to perform a switching operation. An upper shield plate 9 and a lower shield plate 10 that are electrically connected to the energy storage device 20 are disposed inside the insulating cylinder 13 and above the energy storage device 20. The upper shield plate 9 and the lower shield plate 10 are disposed in parallel with each other at a predetermined interval. The upper shield plate 9 is a member that protects electric field concentration on the metal member on the upper side (ground side) of the switching switch 2a, and the lower shield plate 10 is on the lower side (charging unit side) of the switching switch 2a. It is a member that protects the electric field concentration on the metal member.

  As shown in FIG. 3, an internal shield member 14 is disposed so as to cover the seal member 8 and the seal pressing ring 7. The internal shield member 14 is a conductive member formed in an annular shape, and the upper end is attached to the head cover 6 via a fixture and is electrically connected to the head cover 6. The inner shield member 14 can be made of, for example, an aluminum plate material.

  The inner shield member 14 is in a radial cross-sectional view. It has a straight line portion 14a extending vertically and a semicircular curved surface portion 14b. That is, the inner shield member 14 is J-shaped in a radial cross-sectional view. The straight line portion 14 a is disposed along the cylindrical portion of the head cover 6. The curved surface portion 14b is disposed so as to cover a part of the flat surface portion 12 of the seal press ring 7 and the bolt 7a joined to the seal press ring 7 toward the outside of the gas container 2a. The curved portion 14b of the inner shield member 14 covers the vicinity of the lower end portion of the seal retainer ring 7 where the electric field tends to concentrate in ground insulation, so that the concentration of the electric field is alleviated.

  A support insulating plate 22 is attached to the outer periphery of the gas container 2c. The support insulating plate 22 is an elongated plate-like member made of an insulating material. The supporting insulating plate 22 is used for positioning when the switching switch 2a is inserted into the gas container 2c. The supporting insulating plate 22 is attached to the outer periphery of the switching switch 2a and inserted, and the switching switch 2a is positioned by guiding the upper end of the supporting insulating plate 22 so as to match the mounting position of the head cover 6. When the support insulating plate 22 is inserted into the gas container 2 c, the upper end portion is disposed adjacent to the inner shield member 14. The gap between the inner shield member 14 and the support insulating plate 22 has almost disappeared as the gas-insulated load tap changer has become larger in recent years. The number of support insulating plates 22 can be determined as appropriate according to the accuracy required for positioning.

  As shown in FIG. 3, the support insulating plate 22 is formed with a notch 22a. The notch 22a is obtained by notching a portion of the inner shield member 14 near the curved surface portion 14b from the side facing the inner shield member 14 of the support insulating plate 22 toward the vicinity of the center in the axial direction. A predetermined gap d is formed between the support insulating plate 22 and the curved surface portion 14b of the inner shield member 14 by the notches 22a.

  The material constituting the support insulating plate 22 may be an insulating material, and is not limited to a specific material. For example, paper phenol can be used. When the switching switch 2a is inserted, the notch 22a of the support insulating plate 22 may contact the inner shield member 14 to damage the inner shield member 14, but by using flexible paper phenol, Damage can be prevented.

(Function)
The operation of the gas-insulated on-load tap switching device of this embodiment will be described in comparison with a conventional example. In the conventional example shown in FIG. 4, the notch 22 a is not formed in the support insulating plate 22. When the notch 22a is not formed, the gap between the support insulating plate 22 and the curved surface portion 14b of the inner shield member 14 is extremely small as shown in FIG. 4A, and as shown in FIG. A wedge-shaped space S is formed between the curved surface portion 14 b at the lower end of the inner shield member 14 and the support insulating plate 22. There is a possibility that the electric field concentrates locally in the wedge-shaped space S, and the ground insulation performance is deteriorated. The electric field value in the wedge-shaped space may be 1.9 times the allowable electric field value.

  On the other hand, as shown in FIG. 5, in this embodiment, the support insulating plate 22 and the inner shield member 14 are formed by forming a notch 22 a in the vicinity of the curved surface portion 14 b of the inner shield member 14 of the support insulating plate 22. A gap d is formed between the curved surface portion 14b. As a result, the wedge-shaped space S is not formed, and the concentration of the electric field is alleviated. Compared with the conventional example of FIG. 4, the electric field value can be reduced by about 77%.

(effect)
The gas-insulated on-load tap switching device 2 of the present embodiment has an opening at the upper end and a switching switch 2a disposed therein, and a gas container 2c filled with insulating gas, and an opening of the gas container 2c. A head cover 6 fitted to the gas container 2, a seal member 8 that seals between the gas container 2 c and the head cover 6, a seal press ring 7 that is a seal press member that presses the seal member 8, and a seal press ring 7 An inner shield member 14 that covers the lower end portion and is provided with a curved surface portion 14b on the lower side, is attached to the outer peripheral portion of the switching switch 2a, and the upper end portion is disposed adjacent to the inner shield member 14, and the inner shield member 14 And a support insulating plate 22 provided with a notch 22a that forms a predetermined gap with the curved surface portion 14b.

  By providing the support insulating plate 22 adjacent to the inner shield member 14 with a notch 22a that forms a predetermined gap with the curved surface portion 14b of the inner shield member 14, the curved surface portion of the inner shield member 14 is provided. It is possible to prevent a wedge-shaped space S from being formed between 14b and the support insulating plate 22. Thereby, local electric field concentration can be prevented, and the pressure resistance of the gas-insulated load tap changer can be improved.

  The notch 22a is formed by notching a portion in the vicinity of the curved surface portion 14b of the inner shield member 14. By cutting out only the portion in the vicinity of the curved surface portion 14b where the electric field of the support insulating plate 22 is concentrated, the concentration of the electric field can be reduced while maintaining the function of the support insulating plate 22 as a positioning member.

  The support insulating plate 22 may be made of paper phenol. By configuring the support insulating plate 22 with flexible paper phenol, it is possible to prevent the corner portion of the notch 22a of the support insulating plate 22 from coming into contact with the inner shield member 14 and being damaged. As a result, it is possible to prevent the metal powder generated due to the damage of the inner shield member 14 from flowing into the gas container 2c and the ground insulation performance from being deteriorated.

(Second Embodiment)
A gas-insulated on-load tap switching device according to a second embodiment will be described with reference to the drawings. In the following embodiments, the same parts as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the second embodiment, as shown in FIG. 6, the notch 22 b is provided in a form extending from the vicinity of the curved surface portion 14 b of the support insulating plate 22 to the upper end of the support insulating plate 22. That is, the upper end portion of the support insulating plate 22 is narrower than the lower end portion by the notch 22b. By providing the notch 22 b, a gap d is formed between the curved surface portion 14 b of the inner shield member 14 and the support insulating plate 22. As a result, as shown in FIG. 7, local electric field concentration between the curved surface portion 14b of the internal shield member 14 and the support insulating plate 22 can be prevented as in the first embodiment. Specifically, the electric field value can be reduced by about 76% as compared with the conventional example of FIG. As a result, the pressure resistance of the gas-insulated load tap changer can be improved.

(Third embodiment)
A gas-insulated on-load tap switching device according to a third embodiment will be described with reference to the drawings. As shown in FIG. 8, the third embodiment is provided with a notch 22b extending from the vicinity of the curved surface portion 14b to the upper end of the support insulating plate 22 as in the second embodiment. The notch 22b is formed on the side of the support insulating plate 22 facing the inner shield member 14, but on the side opposite to the side where the notch 22b of the support insulating plate 22 is provided, the inner side of the gas container 2c is provided. A projecting portion 22c is provided to project to the top. The overhang portion 22c has the same length and width as the cutout 22b. As a result, the upper end portion of the support insulating plate 22 has a different shape from the lower portion.

  As described in the second embodiment, the upper end of the support insulating plate 22 becomes narrower than the lower end by providing the notch 22b, but the upper end is the same as the lower by providing the overhang 22c. Will have a width. The notch 22b prevents local electric field concentration between the curved surface portion 14b of the inner shield member 14 and the support insulating plate 22, and at the same time, the overhanging portion 22c can reinforce the support insulating plate 22 to ensure positioning. Can be done. In the above example, the overhanging portion 22c has been described as having the same length and width as the cutout 22b. However, as long as the supporting insulating plate 22 can be reinforced as much as necessary, it may not be the same length and width. In this embodiment, the electric field value can be reduced by about 75% compared to the conventional example of FIG.

(Fourth embodiment)
A gas-insulated on-load tap switching device according to a fourth embodiment will be described with reference to the drawings. As shown in FIG. 10, in the fourth embodiment, a guide portion 40 is installed on the outer periphery of the bottom portion of the gas container 2c. The guide part 40 has the same width as the distance from the inner wall of the gas container 2 c to the installation position of the support insulating plate 22. As shown in the enlarged view of FIG. 11, when the support insulating plate 22 is inserted into the gas container 2 c, the guide portion 40 comes into contact with the support insulating plate 22 and positions the support insulating plate 22. If the position of the support insulating plate 22 is not stable, the gap d between the inner shield member 14 provided by the notch 22a and the curved surface portion 14b of the support insulating plate 22 may not be stable, and the electric field may concentrate. By providing the guide portion 40 for positioning the support insulating plate 22, the position of the support insulating plate 22 can be stabilized, and the effect of alleviating the electric field concentration provided with the notches 22a can be ensured.

(Fifth embodiment)
A gas-insulated on-load tap switching device according to a fifth embodiment will be described with reference to the drawings. In 1st Embodiment, it demonstrated that the notch 22a could prevent the internal shield member 14 from being damaged by comprising the support insulating board 22 with flexible paper phenol. In the fifth embodiment, a configuration example for preventing damage to the internal shield member 14 will be described even when the support insulating plate 22 is made of a material having high hardness such as FRP (fiber reinforced plastic). As one configuration example, as shown in FIG. 12, a portion of the inner peripheral surface of the inner shield member 14 facing the FRP support insulating plate 22 is covered with a soft insulator 30. As another configuration example, as shown in FIG. 13, the side of the support insulating plate 22 made of FRP facing the inner shield member 14 is covered with a soft insulator 30. The soft insulator 30 shown in FIGS. 12 and 13 is not limited to a specific material, but a softer material than the material constituting the support insulating plate 22 may be used. As such a soft insulator 30, for example, PTFE (polytetrafluoroethylene) may be used.

  As described above, even when the support insulating plate 22 is formed of high-hardness FRP, the notch is formed by covering one of the opposing surfaces of the support insulating plate 22 and the inner shield member 14 with the soft insulator 30. It is possible to prevent the inner shield member 14 from being damaged by 22a. As a result, the metal powder generated from the inner shield member 14 does not flow into the gas container 2c, and the ground insulation performance can be prevented from deteriorating. Furthermore, the strength of the support insulating plate 22 can be improved by configuring the support insulating plate 22 with a member having high hardness.

  Similarly to the case of using paper phenol, the notch 22a of the support insulating plate 22 can be prevented from damaging the inner shield member 14. As a result, it is possible to prevent the metal powder generated due to the damage of the inner shield member 14 from flowing into the gas container 2c and the ground insulation performance from being deteriorated.

(Sixth embodiment)
A gas-insulated on-load tap switching device according to a sixth embodiment will be described with reference to the drawings. As shown in FIG. 14, in the sixth embodiment, instead of providing the notch 22 a in the support insulating plate 22, the second inner shield member 23 is provided on the opposite side of the support insulating plate 22 from the inner shield member 14. Is disposed adjacent to the support insulating plate 22. The second inner shield member 23 is an annular conductive member that is smaller than the inner shield member 14. The second inner shield member 23 has a straight line portion and a curved surface portion like the inner shield member 14, and has a shape in which the J-shape is reversed left and right in a radial cross-sectional view. The second inner shield member 23 is disposed at the same height as the inner shield member 14 with the curved surface portion facing the inner side of the gas container 2a. That is, the second inner shield member 23 is arranged so as to be line-symmetric with the inner shield member 14 in the radial cross-sectional view with the support insulating plate 22 interposed therebetween.

  In such a configuration, since the support insulating plate 22 does not have the notch 22 a, a wedge-shaped space is formed between the support insulating plate 22 and the inner shield member 14. However, since the second inner shield member 23 is arranged on the opposite side of the support insulating plate 22, a wedge-shaped space is similarly formed between the support insulating plate 22 and the second inner shield member 23. Will be. As a result, as shown in FIG. 15, the concentration of the electric field between the inner shield members 14 of the support insulating plate 22 is alleviated, and the ground insulation performance can be improved. Specifically, the electric field value can be reduced by about 49% compared to the conventional example of FIG. Further, since the support insulating plate 22 is not cut out, the strength of the support insulating plate 22 can be maintained. The second inner shield member 23 may be any member that can alleviate the electric field concentration of the inner shield member 14. The second inner shield member 23 has a shape or installation that is symmetrical with the inner shield member 14 shown in FIGS. 14 and 15. It is not limited to the position. The second inner shield member 23 can appropriately determine an appropriate shape and installation position for relaxing the electric field concentration of the inner shield member 14.

(Other embodiments)
The above embodiment is presented as an example in the present specification, and is not intended to limit the scope of the invention. In other words, the present invention can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and gist of the invention.

  In the third embodiment, the protruding portion 22c is provided on the support insulating plate in which the notch 22b reaching the upper end of the support insulating plate is formed. However, the present invention is not limited to this. For example, the protruding portion 22c may be provided on the support insulating plate 22 in which the notch 22a is formed by notching only the portion in the vicinity of the curved surface portion 14b of the inner shield member 14. Similarly, you may form the guide part 40 demonstrated in 4th Embodiment in the support insulation board in which the notch 22a was formed. Similarly, the soft insulator 30 described in the fifth embodiment may be covered with the support insulating plate 22 in which the notches 22b are formed and the inner shield 14 facing the support insulating plate 22.

DESCRIPTION OF SYMBOLS 1 ... Transformer tank 2 ... Gas insulation type load tap changer 2a ... Switching switch 2b ... Tap selector 2c ... Gas container 3, 4 ... Insulating gas 6 ... Head cover 7 ... Seal press ring 8 ... Seal member 9 ... Upper shield plate 10 ... Lower shield plate 11 ... First outer shield member 12 ... Plane portion 13 ... Insulating tube 14 ... Internal shield member 14a ... Linear portion 14b ... Curved portion 15 ... Second outer shield member 20 ... Energy storage Device 21 ... Drive shaft 22 ... Support insulating plates 22a, 22b ... Notch 22c ... Overhang portion 23 ... Second inner shield member 30 ... Soft insulator 40 ... Guide portion d ... Gap S ... Wedge-shaped space

Claims (10)

A gas container in which an opening is formed at the upper end and a switching switch is disposed inside, and an insulating gas is sealed;
A head lid that fits into the opening of the gas container;
A sealing member for sealing between the gas container and the head lid;
A seal pressing member for pressing the sealing member;
An inner shield member having a curved surface portion covering a lower end portion of the seal pressing member;
Support insulation provided on the outer periphery of the switching switch, having an upper end disposed adjacent to the inner shield member, and provided with a notch that forms a predetermined gap with the curved surface portion of the inner shield member And a gas-insulated on-load tap switching device.   2. The gas-insulated on-load tap switching device according to claim 1, wherein the notch is formed by notching a portion in the vicinity of the curved surface portion of the support insulating plate.   The notch reaches the upper end of the supporting insulating plate from the vicinity of the curved surface portion of the supporting insulating plate, and the upper end of the supporting insulating plate is narrower than the lower end by the notch. The gas-insulated on-load tap switching device according to claim 2, wherein:   The notch is formed on the side of the support insulating plate facing the inner shield member, and the support insulating plate projects to the gas container inside on the side opposite to the side where the notch is provided. The gas-insulated on-load tap switching device according to any one of claims 1 to 3, wherein an overhang portion is provided.   5. The gas-insulated on-load tap switching device according to claim 4, wherein the projecting portion has the same length and width as the notch.   6. The gas according to claim 1, further comprising a guide portion that is provided on an outer peripheral side of a bottom portion of the gas container and positions the support insulating plate in contact with the support insulating plate. Insulated load tap changer.   The gas-insulated on-load tap switching device according to any one of claims 1 to 6, wherein the supporting insulating plate is made of paper phenol.   The said support insulation board is comprised with a fiber reinforced plastic, and the part facing the said support insulation board of the said internal shield member is coat | covered with the soft insulating material. The gas-insulated load tap changer as described in 1.   The support insulating plate is made of fiber reinforced plastic, and the side of the support insulating plate facing the inner shield member is covered with a soft insulating material. The gas-insulated load tap switching device according to item. A gas container in which an opening is formed at the upper end and a switching switch is disposed at the bottom, and an insulating gas is enclosed;
A head lid that fits into the opening of the gas container;
A sealing member for sealing between the gas container and the head lid;
A seal pressing member for pressing the sealing member;
A first inner shield member having a curved surface portion covering a lower end portion of the seal pressing member;
A support insulating plate attached to the outer periphery of the switching switch and having an upper end disposed adjacent to the inner shield member;
A gas-insulated on-load tap changeover comprising: a second internal shield member disposed adjacent to the support insulation plate on the opposite side of the support insulation plate from the first internal shield member apparatus.