JPH0229622Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a gas insulating bushing for oil-filled insulating equipment, which is used at the air outlet of oil-filled insulating equipment.

(Prior art) Air vents used at the air outlet of oil-filled insulating equipment.
Oil-immersed paper capacitor bushings and dry type capacitor bushings are often used as bushings for use in oil, but both require a large number of parts and a long production period, and in particular, the rated voltage is high.
EHV class products require the same amount of time to manufacture as oil-filled insulation equipment, so there was a need to shorten the manufacturing period. Therefore, it may be possible to use gas-insulated bushings, which have a simple structure, a small number of parts, and excellent insulation performance, for the air outlet of oil-filled insulated equipment, but gas-insulated bushings are always Since it is filled with high-pressure SF ₆ gas of 5 kg/cm ² G, it is necessary to separate the SF ₆ gas and oil in order to use it for the air outlet of oil-filled insulated equipment. Not used because there is no spacer to do so. In other words, if a problem occurs in the airtight area created by the spacer, the gas sealed inside the bushing may directly enter the oil-filled insulated equipment, and the intruding gas may accumulate in the high-pressure area or vaporize after being dissolved. This is because there were reliability problems as it caused partial discharges and total circuit breakdown.

(Purpose of the invention) This invention breaks down the conventional technical understanding that gas insulating bushings cannot be used at the air outlet of oil-filled insulated equipment, and is easy to manufacture and highly reliable for oil-filled insulated equipment. The purpose is to provide a gas insulated bushing.

(Structure of the invention) The invention consists of a pair of insulating plates, one of which is rigid and the other flexible, which are airtightly fitted opposite each other at a required interval in the middle of a center connection conductor, each having a center hole. The lower end of the insulator tube has its peripheral edge connected by an annular outer frame, and an insulating spacer filled with a liquid insulator is inserted into the closed chamber formed between the insulating plates, and the center conductor is inserted inside the insulating spacer, and the upper end is closed. The center conductor and the center connection conductor are electrically connected to each other, and the lower end opening of the insulator tube is closed with an insulating spacer to connect them, and the inner cavity of the insulator tube is filled with an insulating gas. It is something.

(Embodiment) Next, the present invention will be explained in detail with reference to the illustrated embodiment. Reference numeral 1 denotes a center conductor inserted into the inside of an insulator tube 2, and the insulator tube 2 has its upper end opening airtightly sealed by a terminal fitting 1a. It's blocked. Further, the lower end opening of the insulator tube 2 is connected to an insulating spacer 10 having a central connecting conductor 3 electrically connected to the lower end of the central conductor 1 via a tulip-shaped connector 12 with a metal connecting fitting 11. They are connected to close the lower end opening. The inner cavity 13 of the insulator tube 2 defined between the insulator tube 2 and the insulating spacer 10 is filled with SF ₆ gas at a pressure of 2 to 5 kg/cm ² G. Further, one end of the insulating spacer 10 is formed at the connection terminal 3a with the center conductor 1, and the other end is formed with the connection terminal 3a with the oil-filled insulating equipment RO.
Insulating plates 4 and 5 made of a plastic plate or the like, one of which is hard and the other of which is flexible, are placed opposite each other in the middle of the center connection conductor 3 formed in FIG. A sealed chamber 7 is formed between the insulating plates 4 and 5 by firmly connecting the peripheral edges of the insulating plates 4 and 5 with a narrow annular outer frame 6. 7 is filled with a liquid insulator 8 such as insulating oil. In addition,
The annular outer frame 6 shown in the embodiment includes an outer frame main body 6' and retaining rings attached to both sides thereof to clamp the peripheries of the above-described hard insulating plate 4 and the other flexible insulating plate 5. 6'', 6'', both sides of the annular outer frame 6, that is, the surfaces of the retaining rings 6'', 6'' are formed into tube end connecting portions 6a, 6b, and the annular outer frame 6 is An appropriate number of bellows 10a are provided as necessary on the outer periphery of the outer frame body 6' to adjust the pressure corresponding to the expansion of the liquid insulator 8 caused by the insulating gas flowing into the sealed chamber 7. I take it as a thing. Further, a detector 10b capable of detecting the presence or absence of insulating gas flowing into the sealed chamber 7 is attached to the top of the bellows 10a as required. Furthermore, when the sealed chamber 7 formed between the insulating plates 4 and 5 has an abacus-shaped cross section as shown in the first embodiment and the second embodiment,
A cylindrical shield electrode 9 is provided around the center connection conductor 3 in the sealed chamber 7, and this shield electrode 9 is connected to the center connection conductor 3.
This is to alleviate the potential difference in the vicinity and to prevent air bubbles from accumulating near the charged part and causing partial discharge in the event that gas leaks in the insulating spacer 10 for some reason. It is sealed by being embedded in a hard insulating plate 4, and the lower end is left open so that the incoming gas is stored at the upper end of the cylindrical gap surrounded by the shield electrode 9. Reference numeral 14 denotes a metal internal grounding shield installed concentrically with the center conductor 1 inside the insulator tube 2, and is fixed to the upper end of the connecting fitting 11. Reference numeral 15 denotes an external grounding shield attached to the lower fitting of the insulator tube 2. 2a to prevent electric field concentration on the upper end of the lower metal fitting 2a, and 16 is a head shield for preventing electric field concentration on the lower end of the insulator tube upper metal fitting 2b. In the above description, the insulating spacer is formed by two opposing straight hard insulating plates 4 and two flexible insulating plates 5, but this flexible insulating plate 5 is shown in FIG. As shown in FIG. 2, a plurality of annular protrusions 5'' may be concentrically formed around the center hole 5a to provide excellent flexibility. This is preferable because it is possible to prevent a partial discharge from occurring in the vicinity of the flexible insulating plate 5 due to foreign matter mixed in the liquid insulator 8 in the sealed chamber 7 and the insulating oil of the oil-filled insulated equipment. As in the third embodiment shown in FIG. 4, if the sealed chamber 7 is not shaped like an abacus and both insulating plates 4 and 5 are made to have an upwardly expanding shape, high safety can be achieved even if there is inflowing gas. The shield electrode 9 may be omitted since it will be stored above the periphery.Furthermore, although not shown, a cylindrical insulating partition surrounding the center conductor 1 may be provided near the inner wall of the insulator tube 2. It is also possible to provide an explosion-proof structure in which the gas spaces within the tank are separated and the two gas spaces are communicated with each other through small-diameter vents that communicate with each other.

With this structure, the lead wire A on the side of oil-filled insulated equipment such as a transformer is connected to the connection terminal 3b of the central connection conductor 3, and the pipe end connection part 6b of the annular outer frame 6 is insulated with oil. By abutting the pipe end flange of the connecting pipe part C of the device and firmly tightening it with a fastener such as a bolt, the pipe end opening of the connecting pipe part C will be properly sealed by the insulating spacer 10. Since the air outlet part is formed by attaching the air outlet part in a fixed state, the air outlet part can be formed extremely easily. Furthermore, an insulating spacer 10 filled with a liquid insulator 8 is interposed between the oil-filled insulating device and the insulating tube 2 into which the center conductor 1 is inserted and whose inner cavity 13 is filled with insulating gas. Therefore, even if the insulating gas inside the insulating tube 2 leaks from the bottom opening side for some reason, it will be completely blocked by the insulating plates 4 and 5 and the liquid insulator 8 sealed in the sealed chamber 7 between them. Therefore, the insulating gas inside the insulating tube 2 will not mix with the insulating oil on the oil-filled insulated equipment side, and even if the seal between the center connection conductor 3 and the center hole 4a of the insulating plate 4 is insufficient, the insulating gas Since the insulating gas mixes with the liquid insulating material 8 in the sealed chamber 7 and is stored above, the insulating gas is appropriately prevented from entering the oil-filled insulating equipment, thereby ensuring safety. Furthermore, as shown in the embodiment, if the shield electrode 9 with its lower end open is arranged around the center connection conductor 3 in the insulating spacer 10, the potential difference in this part can be eliminated and Even if a gas leak occurs, bubbles will not accumulate near the charged part, so partial discharge will not occur. Furthermore, since the insulating plate 5 on the oil-filled insulating device contact side of the insulating spacer 10 is made of a flexible material, the pressure can be automatically adjusted by following the volume change of the liquid insulator 8 within the insulating spacer 10. In addition, a pressure sensor may be provided at the connecting portion between the insulating tube 2 and the insulating spacer 10 so that leakage of the insulating gas sealed in the insulating tube 2 can be detected at an early stage. If a gas detector 10b is provided in the annular outer frame 6 so that the gas can be detected early, safety will be further improved.
Moreover, the insulating spacer 10 has two insulating plates 4 and 5.
Since it is only necessary to assemble the center connection conductor 3 and the annular outer frame 6 as described above and fill the sealed chamber 7 formed inside with the liquid insulator 8, it is possible to replace the conventional oil-immersed paper capacitor bushings or dry type capacitors. Compared to bushings, they have a simpler structure, require fewer parts, can be manufactured in a shorter time, and are easier to install, among other advantages.

(Effects of the invention) As is clear from the above description, the invention has the following effects:
By connecting a specially constructed insulating spacer filled with liquid insulator to the lower end opening of the insulating gas-filled insulator tube with the center conductor inserted inside, it is extremely reliable as an air outlet of oil-filled insulated equipment. This product uses a gas-insulated bushing method that is easy to manufacture and has high heat resistance, and solves the problems of air-to-oil bushings used at the air outlet of conventional oil-filled insulated equipment. As such, it has extremely great practical value.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing the first embodiment of the present invention, FIG. 2 is a partially cutaway front view of the main part,
FIGS. 3 and 4 are partially cutaway front views of essential parts showing second and third embodiments of the present invention. 1: center conductor, 2: insulator tube, 3: center connecting conductor,
4, 5: insulating plate, 4a, 5a: center hole, 6: annular outer frame, 7: sealed chamber, 8: liquid insulator, 10: insulating spacer, 13: inner cavity.

Claims (1)

[Claims for Utility Model Registration] 1. A pair of insulating plates 4, 5, one of which is hard and the other flexible, is placed in the middle of the center connecting conductor 3, with center holes 4a, 5a, respectively, with a required spacing between them. Insulating spacers 10 are airtightly fitted facing each other and connected at their peripheral edges by an annular outer frame 6, and a liquid insulator 8 is filled in a sealed chamber 7 formed between the insulating plates 4 and 5. The center conductor 1 and the central connection conductor 3 are electrically connected to the lower end of the insulator tube 2 into which the center conductor 1 is inserted and whose upper end is closed, and the lower end opening of the insulator tube 2 is closed with an insulating spacer 10. A gas insulating bushing for oil-filled insulated equipment, characterized in that the insulating tubes 2 are connected together and an insulating gas is sealed in the lumen 13 of the insulating tubes 2. 2. A gas insulating bushing for oil-filled insulated equipment according to claim 1, wherein the flexible insulating plate 4 is bellows-shaped with a plurality of concentrically formed annular protrusions.