JPH0754906Y2 - Bushing structure in high pressure gas switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of a bushing portion of a high-pressure gas switch.

[Prior art]

In a high-voltage gas switch used in a high-voltage distribution line, abnormal voltage such as lightning surge may cause an internal short-circuit accident in the case. Therefore, this type of switch has a ground-fault type insulation design in order to minimize damage caused by arc (arc energy) when such an internal short circuit occurs. That is, the intruding abnormal voltage is preceded by a ground fault (flashing) between the central conductor (fixed electrode) of the bushing on the charging portion side and the earth side case near the central conductor.

[Problems to be solved by the invention] However, in the above-mentioned conventional one, the arc is affected by the electromagnetic force and is not limited to a ground fault but develops into an interphase short circuit. If the arc spot is fixed in a case with a small thickness, the case may be melted by the arc heat and a large hole may be formed, causing the structure inside the case to fly out of the case.

Therefore, the present invention is intended to prevent the arc spot from being fixed to the inner surface of the case when an internal short circuit occurs, and to prevent melting damage of the case due to arc heat.

[Means for Solving the Problems]

In order to solve the above problems, the present invention provides a metal case (2) which is grounded and hermetically filled with an arc-extinguishing gas,
A bushing (30) penetratingly provided in the wall of the case (2), a central conductor (9) inserted in the bushing (30), and a fixing provided at a tip of the central conductor (9) inside the case. In the case having an electrode (9a) and a movable electrode (10) provided in the case (2) so as to come into contact with and separate from the fixed electrode (9) when the electric path is opened and closed, the bushing (30) is penetrated. On the inner surface of the wall, a metal tubular member (44) which surrounds the outer circumference of the fixed electrode (9a) with an appropriate insulation distance is provided so that its tip (44a) projects inward from the inner surface of the case. It is characterized in that it is fixed and the tubular member (44) is electrically connected to the case (2).

[Operation and effect of the present invention]

If an abnormal voltage such as a lightning surge enters the switch, a ground fault (flash) will occur between the fixed electrode (9a) on the charging side, which is a weak point in insulation, and the tubular member (44) on the ground side. Happened,
In this case, however, the arc spot on the ground (case) side is fixed to the tip (44a) of the tubular member (44), so the arc heat does not directly reach the case surface and the melting damage of the case is as much as possible. It can be prevented.

Further, the tubular member (44) is fixed so as to surround the fixed electrode (9a) and its tip (44).
Since the arc can be moved smoothly in a), the arc spot does not move to the case surface or nearby members and the damage due to the arc heat can be prevented as much as possible, and at the same time the ground fault can be prevented from developing into an interphase short circuit. it can.

Even if the fixed electrode (9a) and the inner surface of the case (2) are flashed (grounded), the arc spot will move smoothly to the tip (44a) of the tubular member (44) due to the electromagnetic force. Therefore, the same preventive effect as described above can be expected.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a gas switch, in which a main body case 2 made of stainless steel is provided with arc extinguishing devices 3 for three phases in parallel. The arc extinguishing device 3 is of a gas spraying type puffer system, and is a movable cylinder 4 formed of an insulating material such as epoxy resin.
And a fixed screw ring 5 welded and fixed to the inner surface of the side surface 2e of the case 2 through which the bushing on the load side penetrates, one end of which is fixed to the fixed screw ring 5 and the other end of which is slidable on the movable cylinder 4. A fixed piston 6 made of epoxy resin, a piston ring 7, a nozzle 8 made of an insulating material such as epoxy resin, and a rod-shaped fixed electrode 9a, 9a 'which will be described later. The movable electrode 10 is shaped and has a slit on the peripheral surface. Reference numeral 11 denotes a coil spring fitted around the outer peripheral surface of the movable electrode 10. In addition, the nozzle 8 has an inner nozzle 8a in which the movable electrode 10 is screwed inside, an outer nozzle 8b in which the movable electrode 10 is screwed, and an inner nozzle 8a having a concentric positional relationship with the inner nozzle 8a. It is composed of an epoxy resin nozzle guide 8c screwed to the nozzle, and these nozzle 8 and movable cylinder 4 are movable integrally with the operating plate 12 which is opened and closed by the operation of an operation handle (not shown). It is screwed on.

In FIG. 2, 13 is an operating shaft connected to an operating handle (not shown) via a bellows, 14 is an operating lever, and is rotated by a pin 17 with respect to a mounting plate 16 integrally fixed to a corner in the case by a screw 15. It is freely connected. The operating lever 14
The lower end 14b is connected to the operating shaft 13 by the pin 18, and the upper end 14c is rotatably connected to the connecting plate 20 by the pin 21. An arm 23 is fixed to the other end of the connecting plate 20, and the arm 23 is rotatably connected to the interlocking shaft 19 by a pin 22. The interlocking shaft 19 is rotatably provided between the upper surface 2b and the lower surface 2c of the case 2. 24 is an interlocking arm fixed to both ends of the interlocking shaft 19,
The arm 24 is connected to the operating connecting plate 26 by a pin 25, and the other end of the connecting plate 26 is connected to the operating plate 12 integrated with the movable cylinder 4 and the like by a pin 27. The projecting end 27a of the pin 27 is fitted in a slotted guide groove of a guide fitting 28 fixed to the case so as to be movable in the lateral direction of the case.

In addition, reference numerals 30 and 31 respectively denote a bushing on the power supply side and a bushing on the load side which are inserted through the right and left side surfaces 2d and 2e of the case so as to face each other in a straight line, and both bushings have substantially the same configuration. Therefore, both bushings 30 and 31 are
The same members are designated by the same reference numerals for description.

In FIG. 1, 32 is a cone-shaped insulator made of epoxy resin, 9 is a center conductor made of a round bar of copper or the like inserted in the center of the insulator 32, and 9a is a center conductor 9 protruding inside the case. The fixed electrode fixed to the tip of the, 33 is a mounting plate made of stainless steel, the inner peripheral end 33a side is embedded in the insulator 32 via the conductive rubber 48 and the outer peripheral end 33b of the case side surface 2d. Stainless steel mounting tube fixed to the outer surface
It is fixed to the outer edge of 34. 36 is a stainless steel mounting screw tube for cable mounting, which is fixed to the outer surface of the mounting plate 33.
Reference numeral 35 is the above-mentioned insulator that penetrates the through hole 2f on the side surface 2d of the case 2.
A cushioning member made of EP rubber or the like fitted to the taper portion inside the case of 32, 37 a porcelain insulator made of alumina porcelain closely fitted to the cushioning member 35, 39 a portion between the central conductor 9 and the porcelain insulator 37,
A sealing metal such as Kovar is airtightly sealed by brazing or welding. Insulator 37
Between the outer peripheral surface of the and the mounting pipe 34, a sealing metal 40 such as Kovar is used.
It is sealed by a and the auxiliary metal fitting 40b for sealing. Reference numeral 45 is a bush made of EP rubber or the like interposed between the buffer member 35 and the center conductor 9, 43 is a female contact connected to the center conductor 9 and fitted in the recess 32b of the insulator 32 located outside the case. A child, 46 is a protective tube made of stainless steel or the like, which is arranged in the recess 32b so as to surround the female contactor 43.

In the above, the fixed electrode 9a of the bushing 30 on the power supply side is
The fixed electrode 9a 'of the bushing 31 on the load side (specifically, including the central conductors 9 and 9') are linearly arranged with their tips located in the case separated by a predetermined distance. In particular, an arc-resistant metal 9b is fixed to the tip of the fixed power source 9a on the power source side. The fixed electrode 9a '(including the central conductor 9') on the load side has a longer projecting length into the case than that on the power source side, and there is no fixed metal.

Reference numeral 44 is a tubular member protrudingly fixed to the inner surface of the case side surface 2d where the bushing 30 on the power source side is located, and is formed of an arc-resistant metal such as stainless steel. The tubular member 44 is a fixed electrode 9a
It is arranged so as to surround the fixed electrode while maintaining a constant insulating distance L from the peripheral surface of the sealing metal 39 fixed to the case 2, and is electrically connected to the case 2.

Regarding the tubular member 44, when an abnormal voltage such as a lightning surge enters the switch, it precedes between the tip portion 44a of the member 44 on the ground side and the fixed electrode 9a on the charging side. Of course, the insulation coordination is designed so that a ground fault (flashover) occurs, but it also has an appropriate heat capacity so that the member 44 does not completely melt during arcing. Is used, and in order to fix the arc spot at the time of arcing to the tip end portion 44a, the shape of the tip end is formed into a ring shape to facilitate movement on the tip end portion 44a. In other words, by fixing the arc spot, the ground fault is prevented from shifting to the interphase short circuit.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a cross-sectional view of a main part of a switch, FIG. 2 is a front view of the switch with a cover case removed except an operating mechanism, and FIG. It is a principal part sectional view of the bushing on the power source side. 1 ... Gas switch, 2 ... Case, 9 ... Center conductor, 9a
... fixed electrode, 30 ... bushing, 44 ... tubular member, 44
a: tip, L: insulation distance

Claims (1)

[Scope of utility model registration request] 1. A metal case (2) which is grounded and hermetically filled with an arc-extinguishing gas, a bushing (30) penetratingly provided in a wall of the case (2), and the bushing (30). 3
0), the central conductor (9), the fixed electrode (9a) provided at the tip of the central conductor (9) inside the case, and the electric circuit opening / closing for the fixed electrode (9) in the case (2). A metal having a movable electrode (10) provided so as to come into contact with and separate from each other, and a metal which surrounds the outer periphery of the fixed electrode (9a) with an appropriate insulation distance on the inner surface of the wall through which the bushing (30) penetrates. The tubular member (44) made of
A bushing structure in a high-pressure gas switch, wherein a) is fixed so as to project inward from the inner surface of the case, and the tubular member (44) is electrically connected to the case (2).