JP2007089356A - Insulating structure of switchgear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an insulating structure of a switchgear which can reduce an electric field of a triple junction. <P>SOLUTION: In the insulating structure of the switchgear in which a main circuit of a switching apparatus is accommodated in a grounding metal case filled with an insulating gas, and which insulates main circuit conductors constituting the main circuit, or the main circuit conductors and the grounding metal case, the structure is constituted such that a large cross section part 11a enlarged in cross section larger than a region 11a other than an opposing end is formed at the opposing end of an electrode 11 which opposes a grounding part 12 with at least the smallest gap L between, or at the opposing end of the electrode 11 that opposes the grounding part on a small curvature face, and an insulating layer 13 is coated on the surface of the large cross section part 11a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an insulating structure of a switch gear used for power transmission / distribution and power receiving facilities.

  As the conventional switchgear insulation structure, for example, in a switchgear that constitutes a power system by housing various switching devices such as circuit breakers and disconnectors in a sealed container, the main circuit conductor for three phases An insulating structure in which an insulating layer is provided on each surface of the tip of the electrode between the electrodes constituting at least the shortest gap between the main circuit conductor and the container, and an insulating barrier is disposed between the electrodes. It is presented (see Patent Document 1).

JP-A-2000-341816 (first page, FIG. 2)

Three types of materials, ie, metal / insulating layer / insulating medium, that is, a metal container or high-voltage conductor for storing the switchgear, an insulator provided in contact therewith, and an insulating gas that is a gas The part where different kinds of substances come into contact is called a triple junction, and it is known that in such a part, local electric field concentration occurs and the insulation performance is likely to deteriorate.
The conventional switchgear insulation structure has a problem that the electric field at the triple junction is high, which is a weak point of insulation performance, and the withstand voltage characteristic cannot be sufficiently increased.

  Further, in the early stage of the dielectric breakdown process, a preceding discharge called a streamer is generated, but the streamer generated at the electrode portion reaches the insulating barrier surface and propagates through the insulating barrier surface to cause dielectric breakdown. In particular, it has already been confirmed that the surface of the insulator has a fast streamer progress rate. The conventional insulation barrier shown in Patent Document 1 has a problem that no streamer countermeasure is taken and the function as an insulation barrier is not sufficiently exhibited.

  The present invention has been made to solve the above-described problems, and has an object to obtain a switchgear insulation structure capable of lowering the electric field of the triple junction portion. An object of the present invention is to obtain a switchgear insulating structure capable of suppressing streamer progress and improving withstand voltage performance.

  In the insulating structure of the switchgear according to the present invention, the main circuit portion of the switchgear is housed in a ground metal case filled with an insulating gas, and between the main circuit conductors constituting the main circuit portion or the main circuit conductor. In the insulating structure of the switchgear that insulates between the grounded metal cases, each of the facing ends of the electrodes facing at least the shortest gap with respect to the grounding portion or the conductive portion, or the facing end portion of the electrode facing the small curvature surface A large cross section having a larger cross section than the portion other than the end is formed, and the surface of the large cross section is covered with an insulating layer.

  Further, a convex portion is provided so as to surround the opposite end portion in the vicinity of the opposite end portion of the electrode facing at least the shortest gap with respect to the ground portion or the conductive portion, or in the vicinity of the opposite end portion of the electrode facing the small curvature surface. The surface of the opposing end portion including the convex portion is formed and covered with an insulating layer, and the height c of the convex portion is equal to or greater than the distance d from the convex portion to the end surface of the insulating layer.

  Also, a recess is formed around the opposite end in the vicinity of the opposite end of the electrode facing at least the shortest gap with respect to the grounding portion or the conductive portion, or in the vicinity of the opposite end of the electrode facing the small curvature surface. The surface from the tip of the opposite end to the middle of the recess is covered with an insulating layer.

  According to the insulating structure of the switchgear of the present invention, at least the opposite end of the electrode facing at least the shortest gap with respect to the ground portion or the conductive portion, or the opposite end of the electrode facing the small curvature surface, other than the opposite end Since the large cross-sectional part with a larger cross-section than that of the part was formed and the surface of the large cross-sectional part was covered with an insulating layer, the insulating performance of the electrode tip was enhanced by the insulating layer, and the electric field of the triple junction part that became a weak point Since the strength of is weakened by the large cross-sectional portion, dielectric breakdown from the triple junction portion is suppressed, and the withstand voltage performance of the electrode portion can be improved.

  Further, a convex portion is formed in the vicinity of the opposing end portion of the electrode so as to surround the opposing end portion, the opposing end portion including the convex portion is covered with an insulating layer, and the height c of the convex portion is changed from the convex portion to the insulating layer. Since the electric field at the triple junction is relaxed, the dielectric breakdown is suppressed and the withstand voltage performance of the electrode can be improved.

  In addition, a recess is formed in the vicinity of the opposite end of the electrode so as to surround the opposite end, and the insulating layer extends from the tip of the opposite end to the middle of the recess. Can be improved.

Embodiment 1 FIG.
Hereinafter, a switchgear insulation structure according to Embodiment 1 of the present invention will be described with reference to the drawings. First, the overall configuration of the switch gear will be described. FIG. 1 is a cross-sectional view showing a configuration example of a switchgear. As shown in the figure, in a metal jacket 1 covering the whole, ground metal cases 2a to 2c hermetically sealed for housing a main circuit portion of a modular switchgear are arranged. The cases 2a to 2c are filled with an insulating gas such as SF6 gas, dry air, nitrogen gas or air to form an insulating gas atmosphere. The switchgear in the figure is an example of a power receiving unit. A cable head 3 is attached to a side wall of a ground metal case 2a disposed in the lower stage of the metal jacket 1, and a vacuum circuit breaker 4 and a ground switch 5a are provided inside. It is stored. The ground metal case 2b disposed in the upper stage houses the ground switch 5b, the disconnect switch 6, and the three-phase bus 7 connected to the ground switch 5b, and also in the ground metal case 2c disposed adjacent to the ground metal case 2b. Accommodates a three-phase bus 8. The metal cases 2a and 2b are connected by being partitioned by an insulating spacer 9.
Further, on the front side (the left side in the figure) of the metal jacket 1, there are disposed operating mechanisms 10a to 10c of the switchgear housed in the ground metal cases 2a and 2b and a control panel (not shown).

  The present invention provides an insulating structure between the main circuit conductors for three phases or between the main circuit conductors and the ground metal cases 2a to 2c in the switch gear as described above (but not limited to the configuration example shown in the figure). Specifically, for example, in FIG. 1 (a), the part surrounded by the alternate long and short dash line, that is, the part A which is the conductor penetration part of the disconnector case, and the part A which is the insulation operation rod part of the circuit breaker These enlarged views are shown in FIG. 1 (b). However, the present invention is not limited to this portion, and the insulation structure between the main circuit conductors or between the main circuit conductors and the ground metal case is an object as described above. Therefore, in the description of each embodiment below, The relationship between the conductive part and the ground metal case is generally shown as a structure between the electrode and the ground, with the insulating structure as the center. (Although not specifically described, in FIG. 2 and subsequent figures, the grounding portion facing the electrode may be a conductive portion.)

FIG. 2 is a partial cross-sectional view of the electrode portion showing the insulating structure of the switchgear according to the first embodiment. The electrode 11 which comprises a main circuit conductor etc. has shown the state arrange | positioned facing grounding parts 12, such as ground metal cases 2a-2c. A large cross section 11a having a larger cross section than a portion other than the opposite end is formed at the opposite end of the electrode 11 facing at least the shortest gap L, or the opposite end of the electrode 11 facing at a small curvature surface. An insulating layer 13 is coated on the surface of the portion 11a. The thickness of the insulating layer 13 is appropriately determined depending on the shape of the electrode 11, the rated voltage, and the like.
The electrode 11 may be rod-shaped or plate-shaped. If the electrode 11 is rod-shaped, the diameter of the tip is increased, and if it is plate-shaped, the width or thickness of the tip is increased. For convenience of explanation, a portion having a large cross section is referred to as a large cross section 11a, and the other portion is referred to as a small cross section 1b.

Next, the operation of the insulating structure configured as described above will be described.
The insulating layer 13 improves the insulating performance between the opposite end of the electrode 11 and the grounding portion 12. When the insulating layer 13 is provided on the electrode 11 in this manner, as described above, the triple junction portion (in the drawing *) where the electrode 11, the insulating layer 13, and the three kinds of different substances of the enclosed insulating gas are in contact. A mark portion) is formed, and this portion becomes a high electric field. However, since the large cross-sectional portion 11a is provided at the opposite end, the equipotential lines are smoothly spread outward at the portion where the small cross-sectional portion 11b transitions to the large cross-sectional portion 11a, so that the electric field of the triple junction portion is weakened. The electric field is low.

  As described above, according to the invention of the present embodiment, the opposite end of the electrode facing at least the shortest gap with respect to the grounding portion or the conductive portion, or the opposite end of the electrode facing the small curvature surface, is opposed. A large cross-section with a larger cross-section than the part other than the end is formed, and the surface of the large cross-section is covered with an insulating layer, so that the insulating performance of the electrode tip is strengthened by the insulating layer and a triple junction that becomes a weak point Since the strength of the electric field at the portion is weakened by the large cross-sectional portion at the tip of the electrode, dielectric breakdown from the triple junction portion is suppressed, and the withstand voltage performance of the electrode portion can be improved.

Embodiment 2. FIG.
FIG. 3 is a partial cross-sectional view of the electrode portion showing the insulating structure of the switchgear according to the second embodiment. The overall configuration of the switchgear is the same as that of FIG. As shown in FIG. 3, the opposite end portion is wrapped around the grounding portion 12 in the vicinity of the opposite end portion of the electrode 14 facing at least the shortest gap, or in the vicinity of the opposite end portion of the electrode 14 facing the small curvature surface. Thus, the convex portion 14 a is formed, and the opposing end portion including the convex portion 14 a is covered with the insulating layer 15. Here, if the height of the convex portion 14a is c and the distance from the convex portion 14a to the end surface (on the side where the triple junction portion is formed) of the insulating layer 15 is d, c is equal to or greater than d, that is, c ≧ d. Yes.

  The operation of the insulating structure configured as described above will be described. The equipotential lines that continue from the part without the insulating layer 15 through the convex part 14a to the tip part are smoothly spread outward by the convex part 14a, so that the electric field of the triple junction part is weakened and becomes a low electric field. At this time, since c ≧ d, the effect of weakening the electric field of the triple junction portion becomes stronger.

  As described above, according to the invention of the present embodiment, in the vicinity of the opposed end portion of the electrode facing at least the shortest gap with respect to the ground portion or the conductive portion, or the opposed end portion of the electrode facing the small curvature surface. A convex portion is formed in the vicinity so as to surround the opposing end portion, the opposing end portion including the convex portion is covered with an insulating layer, and the height of the convex portion is equal to or more than the distance from the convex portion to the end surface of the insulating layer. Therefore, the insulation performance of the electrode tip is strengthened by the insulating layer, and the electric field strength of the triple junction, which is a weak point, is weakened by the convex part provided on the electrode, so dielectric breakdown from the triple junction is also possible. It is suppressed and the withstand voltage performance of the electrode part can be improved.

Embodiment 3 FIG.
FIG. 4 is a partial sectional view of an electrode portion showing an insulating structure of a switchgear according to the third embodiment. As shown in the figure, the electrode 16 of the present embodiment is at least near the facing end of the electrode 16 facing the grounding portion 12 with the shortest gap or near the facing end of the electrode 16 facing the small curvature surface. Further, a recess 16a is formed so as to surround the opposite end, and the insulating layer 17 covers the end of the opposite end to the middle of the recess 16a. When the electrode 16 is rod-shaped, the recess 16a is annularly provided around the radial direction, and when the electrode 16 is plate-shaped, the recess 16a is formed by a groove extending in the plate width direction.

  In the insulating structure configured as described above, the equipotential lines crossing the concave portion 16 on the surface of the electrode 16 are moved away from the triple junction portion, and accordingly, the electric field of the triple junction portion is weakened.

  As described above, according to the invention of the present embodiment, a recess is formed in the vicinity of the opposite end of the electrode so as to surround the opposite end, and the insulating layer extends from the tip of the opposite end to the middle of the recess. Since it is covered, the insulation performance of the electrode tip is enhanced by the insulating layer, and the strength of the electric field of the triple junction, which is a weak point, is weakened by the step of the concave part of the electrode. It is suppressed and the withstand voltage performance of the electrode part can be improved.

Embodiment 4 FIG.
FIG. 5 is a sectional view of an electrode portion showing an insulating structure of a switchgear according to the fourth embodiment. As shown in the figure, the insulating structure of the present embodiment is a structure in which a recessed portion 18a that is recessed toward the distal end side is provided at the terminal portion that forms the triple junction portion of the insulating layer 18 that covers the surface of the electrode 11. is there.
The electrode shown in FIG. 2 is the same as that shown in FIG. 2 of the first embodiment. However, the present invention is not limited to this, and the shape shown in FIGS. 3 and 4 described in the second and third embodiments may be used.
By forming the termination portion of the insulating layer 18 of the triple junction portion as shown in the figure, the triple junction portion is further away from the equipotential line.

  As described above, according to the invention of the present embodiment, since the depression is provided at the terminal end of the insulating layer of the triple junction portion, the electric field strength of the triple junction portion is further increased compared to the first to third embodiments. Therefore, the dielectric breakdown from the triple junction portion is further suppressed, and the withstand voltage performance of the electrode portion can be improved.

Embodiment 5. FIG.
FIG. 6 is a cross-sectional view of the electrode portion showing the insulating structure of the switchgear according to the fifth embodiment. As shown in the figure, when the electrodes 11 having the same shape are arranged to face each other, an insulating layer is also formed on the tip side of the facing electrodes, and a solid insulation is provided between the respective insulating layers. The object 19 is integrally formed.

The electrode 11 in FIG. 6 is shown as a representative one equivalent to that in FIG. 2 in the first embodiment, but may have a shape equivalent to that in FIGS. 3 and 4 in the second and third embodiments.
Moreover, although the case where the end part of the solid insulator 19 forming the triple junction part is formed with the depression part 19a is shown, this part may also have a shape without the depression part as shown in FIGS.
Furthermore, although the case where the electrodes face each other is shown, one of them may be a ground portion.

  As described above, according to the invention of the present embodiment, the insulating layer is also formed on the grounding portion facing the electrode or the opposite end of the conductive portion, and the two insulating layers are integrated with each other by a solid insulator. Since it formed, the effect similar to the case of Embodiment 1-Embodiment 3 is acquired, and also the withstand voltage performance of the electrode tip part can further be improved.

Embodiment 6 FIG.
FIG. 7 is a cross-sectional view of the electrode portion showing the insulating structure of the switchgear according to the sixth embodiment. As shown in the figure, the electrodes 11 are arranged to face each other, an insulating barrier 20 is arranged between the opposing electrodes 11 in a direction substantially orthogonal to the opposing direction, and the tip of the electrode 11 is formed on the surface portion of the insulating barrier 20. A dish-shaped depression 20a having a depth larger than the outer shape of the insulating layer and a depth of 3 mm or more is formed. The inventors verified by tests that the effects shown below can be exhibited if the depth is 3 mm or more. In addition, it was verified that the shape of the stepped portion around the dish-shaped depression 20a is more effective if it has a right angle or an acute angle that widens the bottom surface as shown in the figure.

Note that the shapes of the electrodes and the insulating layer are not limited to the drawings, and may be the same as those shown in FIGS.
Moreover, although the figure demonstrated the case where electrodes were made to oppose, it may replace with one electrode and may be a grounding part. In this case, it is not necessary to provide the dish-shaped depression on the surface portion of the insulating barrier on the ground side.

  As described above, according to the invention of the present embodiment, an insulating barrier is disposed between an electrode and a grounding portion or a conductive portion facing the electrode in a direction substantially perpendicular to the facing direction. Since a dish-like depression with a depth of 3 mm or more than the outer shape of the insulating layer at the tip of the electrode is formed on the surface of the electrode, the streamer that has advanced from the tip of the electrode and the triple junction passes through the depression on the surface of the insulating barrier. However, the stepped portion of the depression cannot be exceeded, it stays in the depression on the surface of the insulating barrier and does not cause dielectric breakdown, and the withstand voltage performance can be further improved.

It is sectional drawing which shows the structural example of the switchgear in Embodiment 1 of this invention. It is a fragmentary sectional view which shows the insulation structure of the switchgear in Embodiment 1 of this invention. It is a fragmentary sectional view which shows the insulation structure of the switchgear in Embodiment 2 of this invention. It is a fragmentary sectional view which shows the insulation structure of the switchgear in Embodiment 3 of this invention. It is a fragmentary sectional view which shows the insulation structure of the switchgear in Embodiment 4 of this invention. It is a fragmentary sectional view which shows the insulation structure of the switchgear in Embodiment 5 of this invention. It is a fragmentary sectional view which shows the insulation structure of the switchgear in Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal sheath 2a-2c Ground metal case 3 Cable head 4 Vacuum circuit breaker 5a, 5b Ground switch 6 Disconnector 7, 8 Bus 9 Insulating spacer 10a-10c Operation mechanism part 11, 14, 16 Electrode 11a Large cross-section part 11b Small cross section 12 Grounding part 13, 15, 17, 18 Insulating layer 14a Convex part 16a Concave part 18a, 19a Depressed part 19 Solid insulator 20 Insulating barrier 20a Dish-shaped indented part.

Claims (6)

A switch that houses a main circuit part of a switchgear in a grounded metal case filled with an insulating gas, and insulates between the main circuit conductors constituting the main circuit part or between the main circuit conductor and the grounded metal case In the gear insulation structure,
Large cross section with a larger cross section than the other end portions at the opposite end portion of the electrode facing at least the shortest gap with respect to the ground portion or the conductive portion, or at the opposite end portion of the electrode facing the small curvature surface An insulating structure for a switchgear, wherein the surface of the large cross section is covered with an insulating layer. A switch that houses a main circuit part of a switchgear in a grounded metal case filled with an insulating gas, and insulates between the main circuit conductors constituting the main circuit part or between the main circuit conductor and the grounded metal case In the gear insulation structure,
Convex portions are provided so as to surround each of the opposing ends in the vicinity of the opposing end of the electrode facing at least the shortest gap with respect to the grounding portion or the conductive portion, or in the vicinity of the opposing end of the electrode facing the small curvature surface. The surface of the opposite end including the convex is formed with an insulating layer, and the height c of the convex is equal to or greater than the distance d from the convex to the end surface of the insulating layer. Switch gear insulation structure. A switch that houses a main circuit part of a switchgear in a grounded metal case filled with an insulating gas, and insulates between the main circuit conductors constituting the main circuit part or between the main circuit conductor and the grounded metal case In the gear insulation structure,
Concave portions are formed so as to surround each of the opposing end portions in the vicinity of the opposing end portion of the electrode facing at least the shortest gap with respect to the grounding portion or the conductive portion, or in the vicinity of the opposing end portion of the electrode facing the small curvature surface. And an insulating layer covering a surface from the tip of the opposed end to the middle of the recess. In the insulation structure of the switchgear according to any one of claims 1 to 3,
An insulating structure for a switchgear, wherein a recess is formed at a terminal portion of the insulating layer of a triple junction where the electrode, the insulating layer, and the insulating gas are in contact with each other. In the insulating structure of the switchgear according to any one of claims 1 to 4,
The grounding portion facing the electrode or the opposite end of the conductive portion is covered with an insulating layer, and the insulating layer on the electrode side and the insulating layer on the grounding portion or the conductive portion side are covered with a solid insulator. Switchgear insulation structure characterized by being connected and integrated. In the insulating structure of the switchgear according to any one of claims 1 to 4,
An insulating barrier is disposed between the electrode and the grounding portion or the conductive portion facing the electrode in a direction substantially orthogonal to the facing direction, and an insulating layer at the tip of the electrode is formed on the surface of the insulating barrier. An insulating structure for a switchgear, wherein a dish-shaped depression having a depth larger than 3 mm and a depth of 3 mm or more is formed.

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