JPH0458249B2 - - Google Patents

Description

[Detailed description of the invention]

A. Field of Industrial Application The present invention relates to gas-insulated electrical equipment, and more particularly to gas-insulated electrical equipment that includes a conductor that penetrates the side wall of a box filled with insulating gas. B. Summary of the Invention In a gas-insulated electric device, a cylindrical insulator filled with gas is provided on at least one side of a side wall of the box, and a gap size between a conductor insertion hole provided in the side wall of the box and the conductor is provided. g, the length of the inner wall of the cylindrical insulator (length in the axial direction facing the conductor) is l, the inner diameter of the conductor insertion hole is φ ₁ , the inner diameter of the insulator is φ ₂
By setting these dimensions in an optimal relationship, it is possible to downsize the cylindrical insulator and, by extension, downsize the gas-insulated electrical equipment without reducing the dielectric strength voltage. C. Prior Art A gas switchgear is an example of gas-insulated electrical equipment, in which main circuit devices such as a disconnector and a disconnector, and busbars connected to these are housed in a metal box. A configuration is adopted in which the terminal is grounded. in this case,
In order to downsize the equipment housed in the box and to ensure insulation, the box is filled with an insulating gas such as SF ₆ gas or a mixed gas of SF ₆ gas and air. In the gas-insulated switchgear mentioned above, in order to connect the equipment housed in the box with external equipment, a conductor is required to penetrate the side wall of the box, and the conductor and the side wall must be insulated and separated as well as supported. Requires. There are various types of insulating support for the conductor that penetrates the side wall of the box, but the optimal configuration is based on the insulation characteristics of the gas, that is, the one that fully brings out the effect of miniaturization, which is a feature of gas insulation. It is strongly desired to find a structure. Now, conventional gas-insulated electrical equipment will be explained with reference to the schematic diagram shown in FIG. and a busbar room 15. Reference numeral 11 denotes a cylindrical insulator (butting) that penetrates the box side wall 2 and is fixed to the box side wall 2, and an internal fixed conductor 31 is provided passing through the axial center of the bushing. The busbar chamber 15 is filled with an insulating gas such as SF ₆ gas at atmospheric pressure or a pressure higher than atmospheric pressure (0.10 to 0.2 MPa). Reference numeral 18 is a pull-out type disconnector, and the internal fixed conductor 3
It has an external conductor 19 that comes into contact with and separates from the protruding tip 31a of 1, and the contact and separation part is formed as a disconnection part 9. Therefore, when the drawer type disconnector 18 is carried into the disconnector chamber 10, its outer conductor 19 and internal fixed conductor 31
The protruding tip 31a of the protruding end 31a is connected to establish electrical continuity. Therefore, the portion of the cylindrical insulator (butting) 11 will be explained based on FIG. 24. That is, the second
In FIG. 4, a through hole 4 is bored in a side wall 2 of a box body of an electrical device 1 filled with an insulating gas, and a cylindrical insulator 11 is provided protruding from the outside of the through hole 4. Cylindrical insulator 1
1 has a flange portion 11a and a boss portion 11b, and a sealing material 2 such as an O-ring is attached to the flange portion 11a.
It is hermetically coupled to the side wall 2 of the box body with bolts 20 via 3. On the other hand, an internal fixed conductor 31 is provided in this cylindrical insulator 11 with a sealing material 22 such as an O-ring interposed therebetween, and passes through the cylindrical insulator 11 in an airtight manner. FIG. 23 shows a model of the cylindrical insulator 11 shown in FIG. 24. Then, the insulation voltage characteristics of the modeled cylindrical insulator 11 shown in FIG. 23 were investigated. FIG. 22 shows the results in a graph. I will explain it below,
The meanings of the symbols used in FIGS. 23 and 24 are as shown in the table below. L: Length of the outer wall of the cylindrical insulator protruding outward from the side wall of the box (mm) φ ₁ : Inner diameter of the conductor insertion hole (mm) φ ₂ : Inner diameter of the cylindrical insulator (mm) φ ₃ : Cylinder Outer diameter of the cylindrical insulator (mm) a: Gap dimension (mm) between the inner periphery of the conductor insertion hole and the cylindrical insulator. The boss portion 11b of the cylindrical insulator 11 has no effect or adverse effect on the creeping electric strength characteristics of the cylindrical insulator 11, and in the configurations shown in FIGS. 23 and 24, φ ₁ , φ ₂ , φ ₃ , a It has been confirmed that if both and L are the same, the withstand voltage characteristics of the two are the same in various shapes and sizes,
The results are omitted here. _The experimental results _shown in FIG. 22 are as follows for _the cylindrical insulator 11 shown in FIG.
The experiment was carried out by changing L according to the outer diameter of the 10 mm conductor 3 (the aluminum round bar is 30 mm) and in pure SF ₆ gas at a pressure similar to atmospheric pressure (about 0.1 MPa). The results are as shown in Figure 22. As can be seen from the figure, the flash voltage characteristics of positive and negative polarities are reversed when L dimension is around 38 mm, and by increasing L beyond this, positive polarity can be changed. This shows that although the withstand voltage characteristics of the negative polarity are increased, the withstand voltage characteristics of the negative polarity are actually decreased. The reason for this is thought to be that the cylindrical insulator 11 penetrates the box side wall 2. Furthermore, it is conceivable that the minute gap a between the internal conductor 31 and the conductor insertion hole 4 is also a cause. D Problems to be Solved by the Invention In the end, as long as the cylindrical insulator 11 penetrates the box side wall 2, the creepage distance between the internal fixed conductor 31 and the box side wall 2 can be increased by increasing L. It was found that even if attempts were made to overcome the problem of withstand voltage characteristics, the withstand voltage characteristics would not improve. In other words, if L is increased to increase the creepage, the positive breakdown voltage characteristics will improve, but
On the contrary, the negative breakdown voltage characteristics deteriorate. If L is increased, creeping voltage withstand characteristics will be improved, but in practical terms, the electrical equipment housing will become larger. Further, if L is increased in order to improve the creepage withstand voltage characteristics, new problems will arise. In other words, dielectric breakdown occurs between the inner diameter part of the conductor insertion hole 4 of the box side wall 2 and the internal fixed conductor 31, penetrating the cylindrical insulator 11. Electrical equipment adopts a low value of withstand voltage characteristics as a usable voltage condition for safety reasons, so conventional insulators (buttings) that penetrate walls have almost no withstand voltage even if they are made large. No improvement in characteristics could be expected. Moreover, increasing the dimension L increases the weight, and there are also problems such as the labor required to attach the bushings. An object of the present invention, based on the results of various experimental studies, is to provide a gas-insulated electric device having a conductor penetration structure that does not reduce dielectric strength voltage despite being small and lightweight. E. Means for Solving the Problems The gas-insulated electrical equipment according to the first invention stores the electrical equipment and the conductor in a box, and also fills in an insulating gas, and inserts the conductor into the box by penetrating the side wall of the box. In a gas-insulated electric device, the cylindrical insulator is provided on at least one side of the side wall of the box body, and the cylindrical insulator is provided on at least one side of the side wall of the box body. The gap dimension between the inner periphery of the conductor insertion hole provided in the side wall of the box body and the conductor is g, and the length of the inner wall of the cylindrical insulator is When the length is l, the inner diameter of the conductor insertion hole is _φ1 , and the inner diameter of the insulator is _φ2 , l≧g/4,
Moreover, it is characterized in that it is provided in a relationship of φ ₂ −φ ₁ /2≧2 mm. In the second invention, a cylindrical insulator is provided to protrude outside the side wall of the box body, and its inner recessed part is filled with insulating gas, and the end of the internal fixed conductor provided inside the box body is connected to the conductor of the side wall of the box body. The insertion hole is loosely inserted into the cylindrical insulator, and the connecting conductor, which is provided with the cylindrical insulator airtightly and movably in the axial direction, is attached to the internal fixed conductor and can be freely connected and disconnected. forming a section;
In this configuration, the dimensions g, l, φ ₁ , φ ₂ of the part are set in the relationship l≧g/4 and φ 2 −φ 1 /2 ≧ 2 mm, as in the first invention, and further, the dimensions g, l, φ 1 , φ 2 of the part are set in the relationship of l≧g/4 and φ ₂ −φ ₁ /2 ≧ 2 mm, and further, the dimensions of the part are The insertion dimension B of the internally fixed conductor is set to the relationship B≧g/5. F Experimental Results In the Case of SF ₆ Gas The present inventor conducted various experiments regarding the insulation structure of the conductor penetration portion of the side wall of the box in gas-insulated electrical equipment. This will be explained below, as shown in Figures 11 and 13.
The meanings of the symbols in the figures, FIGS. 17 and 20 are as shown in the table below. l: Length of the outer wall of the cylindrical insulator protruding outward from the side wall of the box (mm) φ ₁ : Inner diameter of the conductor insertion hole (mm) φ ₂ : Inner diameter of the cylindrical insulator (mm) φ ₃ : Cylinder Outer diameter of the shaped insulator (mm) g: Gap dimension between the inner periphery of the conductor insertion hole and the conductor (mm) First, in a sealed box filled with SF ₆ at atmospheric pressure (approximately 0.10 MPa), As shown in the figure, a conductor insertion hole 4 is formed in a flat plate 21 (thickness 1.2 mm) corresponding to the side wall of the box body, and a conductor 3 with a diameter of 30 mm is formed in the center of the hole 4.
(aluminum round rods) and applied a high voltage to conduct an experiment on the flash characteristics of conductor penetrations. The inside of the box is evacuated in advance, and then SF ₆ gas is brought to atmospheric pressure (approx.
0.10MPa). Then, a voltage was applied to the conductor 3, the flat plate 21 was grounded, and flash voltage characteristics were determined. Figure 12 shows the results, and the positive and negative polarity impulse flashing is plotted with the hole diameter φ ₁ provided in the flat plate 21 and the gap dimension g between the conductor 3 and the conductor insertion hole 4 on the horizontal axis when the diameter of the conductor 3 is constant. Voltage characteristics (50%FO
V., kV). As can be seen from the figure, as the hole diameter φ ₁ increases, the withstand voltage characteristics for both positive and negative polarities increase proportionally. Next, as shown in FIG. 13, a cylindrical (cup-shaped) insulator 11 with a boss portion 11b made of baking material having φ ₁ <φ ₂ and a length l of the inner wall is formed.
is airtightly fixed to one side (outer side) of the box side wall 2 and also to the conductor 3, and SF ₆ gas is applied to the box and the insulator 11 at atmospheric pressure (approx.
An experiment was conducted on the flash fault voltage characteristics of conductor penetrations by filling the conductor with a pressure of 0.10 MPa. That is, the hole diameter φ ₁ of the box side wall 2, the inner diameter φ ₂ of the cylindrical insulator 11, and the gap dimension g between the conductor 3 and the hole of the box side wall 2 are changed as shown in the table below. voltage was applied. Note that the outer diameter of the conductor 3 is 30 mm.

[Table] As shown in the previous table, Figure 14 shows the flash fault voltage characteristics when each dimension is changed. As can be seen from FIG. 14, the flashover value when l=0 is lower for positive polarity than for negative polarity. Then, when the inner wall length l of the cylindrical insulator 11 is gradually increased, the flash voltage value increases significantly in the positive polarity and gradually increases in the negative polarity.
It can be seen that the polarity dependence reverses at , and eventually stops improving. This is because the flat plate 21, which is a metal member at earth potential, is present, and the withstand voltage characteristics depend on this. An example of a comparison between the results in Figure 14 and Figure 12 is shown below.

[Table] As can be seen from this comparison, the case shown in FIG. 13 has improved voltage resistance characteristics, albeit slightly, compared to the case shown in FIG. 11. Next, the withstand voltage characteristics due to the presence of the flat plate 21, which is a metal member, were investigated. In the experiment, the outer diameter of the conductor was 30 mm φ ₁ = l = 75 mm g = 22.5 mm, the other conditions were the same as in Fig. 14, and the inner diameter dimension φ ₂ of the cylindrical insulator 11 was varied. , the results shown in FIG. 15 were obtained. In other words, the horizontal axis in Fig. 15 represents the change in φ ₂ ,
It is shown as φ ₂ −φ ₁ /2, and it can be seen that if φ ₂ −φ ₁ /2≈2 mm or more, the flash fault voltage characteristics hardly change, but if it becomes less than that, the characteristics suddenly deteriorate. From the results of the above experiments (FIGS. 11 to 15), the following was found. The flash characteristics of positive and negative polarities take the same value (see Figure 14) when l≒5 mm when g=22.5 and when l≒10 mm when g=37.5. From this, it can be seen that the following relationships are established: l:g=5:22.5 l≒g/4 l:g=10:37.5 l≒g/4, and the length l of the inner wall of the cylindrical insulator 11 is at least l≧ It has been found that setting the dielectric strength to g/4 is effective for improving the dielectric strength. Furthermore, from the results shown in FIG. 14, it was found that there is no effect even if the length l of the inner wall of the cylindrical insulator 11 is increased indefinitely. That is, when φ ₁ =75, φ ₂ =80, and g=22.5, the flash characteristics hardly change for either positive polarity or negative polarity when l≈75 or more. Further, when φ ₁ =105, φ ₂ =110, and g=37.5, the breakdown voltage characteristics hardly change for both positive and negative polarity when l≈105 or more. In other words, it has been found that regardless of the value of g, as long as the length l of the inner wall of the cylindrical insulator 11 is approximately the same length as the hole diameter _φ1 , the withstand voltage characteristics hardly improve even if it becomes longer. Therefore, the length l of the inner wall of the cylindrical insulator 11
It has been found that it is better to set at least l≧g/4, and preferably l≈φ ₁ .
Of course, l>φ ₁ may also be satisfied, and in this case, there are requirements other than voltage resistance characteristics, for example, when a current transformer (CT) is directly attached to the outside of the cylindrical insulator 11. At the same time, it was found that the relationship between the inner diameter φ ₂ of the cylindrical insulator 11 and the inner diameter φ ₁ of the conductor insertion hole 4 should be set to φ ₂ −φ ₁ /2≧2 mm (the insertion hole 4 should have a small diameter). Ivy. In the case of a mixed gas of SF ₆ and air
This study investigated the flash fault characteristics of the sidewall penetrating conductor in a box filled with SF ₆ gas, and found that a mixture of SF ₆ gas and air has a higher withstand voltage than pure SF ₆ gas at a certain proportion. It has been known. Therefore, based on the above, the inventors of the present invention
Using the configuration shown in Figure 1 (inserting a conductor with an outer diameter of 30 mm into a hole of φ ₁ = 105 provided on a flat plate), we investigated the flashover voltage characteristics in a mixed gas of SF ₆ and air by changing the ratio of both. Examined. The conductor has an impulse voltage (1.2
×50μs) was applied. Also, the mixed gas ratio is
Experiments were conducted by varying the mixing ratio of SF ₆ gas and air between 100% SF ₆ gas and 100% pure air. The results of the experiment are shown in Figure 16, and it was found that as the mixing ratio of SF ₆ gas increases, the withstand voltage increases, and when a negative voltage is applied, it has a maximum value around 90% SF ₆ . 100 if ₆ gas is 40% or more
It was also found that it has the same voltage resistance characteristics as % _SF6 . Therefore, the mixture gas of SF ₆ and air (SF ₆ is
40% or more, preferably around 90%) was found to be more advantageous in improving the withstand voltage characteristics in the conductor penetration portion. In this way, in the case of a mixed gas of SF ₆ and air, higher withstand voltage characteristics were obtained than pure SF ₆ depending on the mixing ratio, so the inventors conducted experiments using this mixed gas. Proceeding further, we further investigated the withstand voltage characteristics. That is, the flashover voltage characteristics depending on the gap dimension g between the conductor 3 and the conductor insertion hole 4 and the flashover voltage characteristics depending on the end shape of the conductor insertion hole 4 were investigated. Therefore, the structures shown in FIGS. 17A and 17B had the best withstanding voltage characteristics. 90% SF ₆ −
Filling the box and the cylindrical insulator 11 with a mixed gas of 10% air at a pressure similar to atmospheric pressure (approximately 0.10 MPa), changing the length l of the inner wall of the cylindrical insulator 11, The withstand voltage characteristics based on the gap dimension g between the conductor 3 and the conductor insertion hole 4 were investigated while examining the dependence on the l dimension. In addition, in FIGS. 17A and 17B, the thickness of the box side wall 2 is 1.2 mm, and the outer diameter of the conductor 3 is 30 mm. Also,
So that the existence of the cylindrical insulator 11 can be sufficiently ignored,
From the experimental results shown in FIG. 15, the inner diameter φ ₂ of the cylindrical insulator 11 is set to be 10 mm larger than the inner diameter φ ₁ of the conductor insertion hole 4 (φ ₂ =φ ₁ +10 mm). Also,
The conductor insertion hole 4 in FIG. 17A is in the same state as the hole is drilled in the plate (burrs have been removed), while the conductor insertion hole 4 in FIG. 17B has a radius of 10
It is bent with a curvature of mm to create a shape that alleviates the electric field. The experiment uses a negative polarity impulse voltage (1.2 x 50 μs)
This was done by applying . (This is based on the fact that the withstand voltage characteristics are worse in the case of negative polarity than in the case of positive polarity, so the tendency of the characteristics can be clearly seen by examining the negative polarity.) The experimental results are shown in Figures 18A and 18. The result is as shown in Figure B. In Fig. 18, the horizontal axis represents the gap dimension gmm between the conductor 3 and the conductor insertion hole 4, and the vertical axis represents the gap dimension gmm between the conductor 3 and the conductor insertion hole 4.
Negative polarity impulse flash voltage characteristics (50%, FO
V., kV). The following was found from the figure. (1) From the results of Figure 18 A and B, Figure 17 A and B
Both structures are pure SF ₆ (Figure 12)
It was confirmed that the withstand voltage characteristics were improved compared to . (2) From the results shown in Figure 18A, in the structure shown in Figure 17A, if the gap dimension g is 20 mm or more, the inner wall length dimension l in the range of 20 to 100 mm has almost the same withstand voltage characteristics. It was confirmed that the l dimension is not affected by the withstand voltage characteristics as long as the l dimension is above a certain level. (3) From the results shown in Figure 18B, in the structure shown in Figure 17B, l is low in the range of 0 to 10 mm;
It was confirmed that in the range of 40 to 100 mm, almost the same withstand voltage characteristics were exhibited, and as long as the l dimension was above a certain level, the l dimension did not affect the withstand voltage characteristics. (4) Furthermore, when comparing Figure 18 A and B, the first
In the case of Figure 8B, that is, in the case of the structure in which the inner circumferential side of the conductor insertion hole 4 is bent to alleviate the electric field as shown in Figure 17B, the withstand voltage characteristics are slightly improved (about 5 kV). It turned out that there was almost no difference between the two. Based on the above results, the inventors conducted a more detailed investigation. That is, since it is good for the cylindrical insulator 11 to be as short as possible in terms of size and weight reduction, the withstand voltage characteristics depending on the l dimension were investigated in detail. The experimental conditions were as shown in Fig. 17 A, B, Fig. 18 A,
Under the same conditions as case B, and with g dimension of 22.5 mm.
The withstand voltage characteristics were investigated with various l dimensions for the two types, 37.5 mm (see the table below).

[Table] As a result, the results shown in FIG. 19 were obtained. For comparison, the results shown in FIG. 14 (negative polarity impulse) are shown together with dotted lines. The following was found from the results shown in FIG. (1) It was confirmed that the withstand voltage characteristics were improved compared to pure SF ₆ (results shown in FIG. 14). (2) Although the structure shown in FIG. 17B has better voltage resistance characteristics than the structure shown in FIG. 17A, it was found that there is almost no difference between the two. From the above results (Figs. 17 to 19), the shape of the inner circumferential side of the conductor insertion hole 4 provided in the box side wall 2 has little effect on the withstand voltage characteristics.
It is sufficient to drill holes in a flat plate made of metal and remove burrs (see Figure 17A), but it is necessary to curve the surface (or attach a ring) as shown in Figure 17B to alleviate the electric field. It turned out that there was no need to take any action. Summary of the above experiments To summarize the above, the following can be said. (1) The relationship between the gap dimension g between the inner periphery of the conductor insertion hole and the conductor and the length dimension l of the inner wall of the cylindrical insulator is l≧g/4. (2) It is preferable that the l dimension be equal to the inner diameter dimension φ ₁ of the conductor insertion hole (l≈φ ₁ ). (3) The relationship between the inner diameter dimension φ ₁ of the conductor insertion hole and the inner diameter dimension φ ₂ of the insulator should be φ ₂ −φ ₁ /2≧2 mm. (4) Rather than using pure SF ₆ gas, it is better to use a mixed gas of SF ₆ and air, with the SF ₆ content being 40% or more, preferably around 90%, for better withstand voltage characteristics. (5) It has been found that the shape of the inner circumference of the conductor insertion hole has almost no effect on withstand voltage characteristics, and it is sufficient to remove burrs around the drilled hole without performing complicated processing to alleviate the electric field. To be. New Experiments Based on the results obtained from the above experiments, the inventor further conducted the following experiments. That is, this was an experiment for forming a disconnection section within the cylindrical insulator 11. In other words, in the experiment described above, the conductor 3 penetrated the box side wall 2 to a sufficient length, whereas as will be explained later in FIG. Is it possible to make it smaller? Therefore, whether there is a difference between the case where the end of the conductor 3 that slightly penetrates the box side wall 2 is located inside the cylindrical insulator 11 and the above experimental results, and under what conditions there is a difference. This is to check whether the The experiment is the 20th
The configuration shown in the figure was used. In Fig. 20, the inner diameter of the conductor insertion hole φ ₁ = 75 mm, the inner diameter of the cylindrical insulator φ ₂ = 85 mm, the gap dimension between the inner circumference of the conductor insertion hole and the conductor, g = 22.5 mm, the conductor diameter = 30 mm, and the cylindrical insulator. The inner wall of the insulator 11 is sufficiently long (inner wall 15 mm), and the gas filled in the box and the inner recessed part of the cylindrical insulator 11 is 90% SF ₆ -10% air (Fig. 21). ●−●) SF ₆ (Fig. 21〇−〇).The gas pressure was atmospheric pressure (approximately
0.10MPa). The results are shown in FIG. 21 (only for negative polarity impulses). That is, it has been found that stable voltage resistance characteristics can be obtained if the insertion dimension B of the conductor 3 into the cylindrical insulator 11 is about 5 mm or more. In other words, it was found that the following relationship holds: B/g=5/22.5≒1/5 B≧1/5×gmm. Therefore, the tip portion 3a of the conductor 3 extends beyond the conductor insertion hole 4 of the box side wall 2 by approximately B≧1/5g into the cylindrical insulator 1.
1, results similar to those shown in FIGS. 14, 15, and 19 were obtained, and it was confirmed that a disconnection section could be formed within the cylindrical insulator 11. G Examples Six examples of the cylindrical insulator according to the present invention based on the results supported by the various experiments described above are shown in FIGS. 1 to 8, and will be described below. First Embodiment In the first embodiment shown in Fig. 1, 5 is a box body such as a switchgear that houses electrical equipment and is filled with an insulating gas such as pure SF ₆ gas or a mixed gas of SF ₆ and air. In the figure, the right side of the box side wall 2 is the inside of the box and is filled with gas. The cylindrical insulator 11 has a flange portion 11a and a boss portion 11b, and the flange portion 11a is connected to the side wall of the box body.
It is fixed to the outside of the body with a bolt 20 via a sealing material 23. In addition, the boss portion 11 of the cylindrical insulator 11
A long conductor 3 passes through b through a sealing material 22 in an airtight manner. The inside concave portion 24 of the cylindrical insulator 11 is filled with the same insulating gas as the inside of the box 5. Further, the specific dimensions in FIG. 1 are as follows: conductor diameter = 30 mm g = 30 mm φ ₁ = 90 mm φ ₂ = 95 mm l = 30 mm. In the first embodiment, the length l of the inner wall of the cylindrical insulator 11 and the conductor insertion hole 4 provided in the side wall 2 of the box body are
The gap dimension g between the conductor 3 and the conductor 3 is set to l=g based on the above-mentioned experimental results. Furthermore, in the first embodiment, φ ₂ >φ ₁ and φ ₂ −φ ₁ /2≈2.5 mm. That is, the inner wall dimension of the cylindrical insulator 11 is larger than that of the conductor insertion hole 4, and the inner wall of the conductor insertion hole 4 protrudes inward (towards the conductor 3) by about 2.5 mm.
Note that the inner wall of the conductor insertion hole 4 protrudes inward by approximately 2.5 mm, which also applies to the second to sixth embodiments described below. Further, the peripheral wall of the conductor insertion hole 4 is deburred. This eliminates the need to unnecessarily increase the length of the cylindrical insulator 11, and further reduces the size, which is a characteristic of gas insulation. Moreover, the weight is small,
Moreover, it is small and easy to handle. Second Embodiment In the second embodiment shown in FIGS. 2 and 3,
Reference numerals 5 and 5 designate two boxes, such as switchgear, which house electrical equipment and are filled with an insulating gas such as pure SF ₆ gas or a mixture of SF ₆ gas and air.
The box side walls 2, 2 are spaced apart from each other by a constant distance, and are connected by a cylindrical insulator 11. Both side flange parts 1 of the cylindrical insulator 11
1a is applied to the side wall 2 of the box body with a sealing material 6 interposed therebetween, and is hermetically fixed with bolts and nuts. The conductor 3 is guided from one box 5 to the other box 5 by passing through the center of the cylindrical insulator 11, and is supported by a support insulator 7 attached to the inner wall of each box 5, 5. ing. In the second embodiment, the conductor 3 is of one phase, and the cylindrical insulator 11 has a circular cross section. Also in this second embodiment, the cylindrical insulator 1
The length l of the inner wall 1 and the gap g between the conductor insertion hole 4 provided in the side wall 2 of the box body and the conductor 3 are set as l>g/4 based on the results of the above-mentioned experiment. Also in the second embodiment, φ ₂ >φ ₁ and φ ₂ −φ ₁ /2 ≈2.5 mm. Third Embodiment FIG. 4 shows a third embodiment. While the second embodiment had one phase, this third embodiment shows a three-phase example, and accordingly, the cylindrical insulator 11 The cross-sectional shape of the three-phase conductors 3, 3,
3 has a cross-sectional structure that allows it to be inserted all at once. In this case, the dimensional conditions of the length l of the inner wall of the cylindrical insulator 11 and the gap dimension g are set such that l>g/4. Fourth Embodiment FIGS. 5 and 6 show a fourth embodiment, in which the cross-sectional shape of the cylindrical insulator 11 in the three-phase case is circular, unlike the case in FIG. 4. In this case as well, the dimensional conditions for the dimensions l and g of the cylindrical insulator 11 are as follows:
It is set so that l>g/4. Fifth Embodiment FIG. 7 shows a fifth embodiment. In this fifth embodiment, the cylindrical insulator 11 has one end of the cylindrical portion secured to the outside of the box side wall 5 through a sealing material 6 with bolts and nuts, and the cylindrical insulator 11
The other end of the cylindrical portion is airtightly fixed to the conductor 3, and a pleat 8 is provided on the outer periphery of the adhesion portion to extend the creepage distance in the atmosphere. Also in this fifth embodiment, the length l of the inner wall of the cylindrical part of the cylindrical insulator 11, the hole diameter φ ₁ of the conductor insertion hole 4 of the box side wall 2,
The gap dimension g between the conductor insertion hole 4 and the conductor 3 is l
>g/4 (including l≈g/4). If necessary, under the above conditions, a cylindrical insulator 11 is also provided inside the box side wall 2 as shown by the two-dot chain line in FIG.
Alternatively, the other end may be fixed to the conductor 3, thereby ensuring reliable support of the conductor. In addition, the same insulating gas as inside the box may be filled in the cylindrical insulator 11 (in this case, a hole is opened in the side wall of the box for communication), or the inside of the cylindrical insulator 11 is sealed and pressurized gas is filled. It's okay. Sixth Embodiment FIG. 8 shows a sixth embodiment in which the end of the internal fixed conductor 31 is located in the inner recess 24 of the cylindrical insulator 11, and the disconnection part 9 is formed in the recess. show. That is, in FIG. 8 (showing the disconnected state),
Reference numeral 32 denotes a connecting conductor, which passes through the boss portion 11b of the cylindrical insulator 11 via a sealing material 22 so as to be airtight and movable in the axial direction (horizontal direction in the figure). 14
is a retaining ring provided on the connecting conductor 32 to prevent it from slipping out. The outer periphery of this connection conductor 32 may be covered with an insulator. Moreover, a multi-contact 13 is provided inside the tip of the internal fixed conductor 31 located inside the box, and when the connecting conductor 32 moves to the right in FIG. It is connected to the fixed conductor 31. Further, the tip of the internal fixed conductor 31 enters the concave portion 24 from the opening of the cylindrical insulator 11 by a dimension B (g/5 or more). It should be noted that the point that the cylindrical insulator 11 is attached to the side wall 2 of the box housing the electrical equipment is the same as in the first embodiment, so the same parts are given the same reference numerals and the explanation will be omitted. In Fig. 8, internal fixed conductor diameter = 30 mm, disconnection gap dimension G = 45 mm, g = 30 mm, φ ₁ = 90 mm, φ ₂ = 95 mm, B = 18 mm, l = 110 mm, except for B≧g/5 dimension, G dimension, and l dimension. The dimensional relationships of g, φ ₁ and φ ₂ are the same as in the first embodiment. H Specific Application Example First Application Example FIG. 9 shows a switchgear 1 to which the cylindrical insulator 11 according to the first embodiment of FIG. 1 is applied. In the figure, a busbar chamber 15 of the switchgear 1 filled with insulating gas
A cylindrical insulator 11 is provided on the outside of the box side wall 2 that partitions the side and the disconnection chamber 10 (on the side of the disconnection and disconnection chamber), and is connected to the power bus and the load side cable in the busbar chamber 15. Each of the internal fixed conductors 31 hermetically penetrates the boss portion 11b of the cylindrical insulator 11 and projects toward the breaker chamber 10 side. The figure shows a connected state in which the drawer and disconnector 18 have been carried into the disconnector chamber 10 and the external conductor 19 and the internal fixed conductor 31 are connected. The other configurations are the same as the conventional example shown in FIG. Second Application Example FIG. 10 shows an insulating gas-filled switchgear 1 to which the cylindrical insulator (butting) 11 according to the sixth embodiment of FIG. 8 is applied. In the figure, a cylindrical insulator 11 is placed on the outside of the box side wall 2 (that is, on the side of the breaker chamber).
This is the same as the first application example. and,
The connecting conductor 32 passes through the boss portion 11b of the cylindrical insulator 11 in an airtight and slidable manner, and the tip of the internal fixed conductor 31 that connects to the power supply side bus and the load side cable in the busbar chamber 15 is A predetermined dimension (namely, dimension B shown in FIG. 8) is inserted inward from the opening edge of the cylindrical insulator 11. The figure also shows the state where the drawer and disconnector 18 are carried into the disconnector chamber 10 and immediately before connection,
At this position, the connecting conductor 32 has moved toward the edge and the disconnector chamber and is separated from the internal fixed conductor 31, and the outer end of the connecting conductor 32 is in contact with the outer conductor 19 of the drawer and disconnector 18. ing. From this state, by further pushing in the drawer shape and disconnector 18, the connection conductor 32
moves inward and comes into contact with the internal fixed conductor 31 to be in a connected state. The other configurations are the same as the first application example. Note that in the second application example, the cylindrical insulator 11
A disconnection section 9 is formed in the recessed section 24 filled with an insulating gas (that is, the connection conductor 3
2 and the internal fixed conductor 31 are connected to and separated from each other), the disconnection between the drawer type disconnector 18 and the internal fixed conductor 31 of the switchgear 1 is performed in an insulating gas. As shown in the figure, the dielectric strength is improved compared to the case where the circuit is disconnected in the atmosphere (in the blockage or disconnection chamber 10), and in this respect, the insulation space can be reduced, and the switchgear can be further downsized. I. Effects of the Invention According to the gas-insulated electrical equipment according to the present invention, a cylindrical insulator surrounding a conductor penetrating the side wall and whose inside is filled with the same insulating gas as the box body is attached to the side wall of the box body. The length l of the inner wall of the cylindrical insulator attached to the side and the gap dimension g between the conductor insertion hole provided in the side wall of the box and the conductor are l≧g/4, and the through hole φ ₁ in the side wall of the box By setting the relationship between φ ₂ and the inner diameter φ ₂ of the cylindrical insulator to φ 2 - _{φ 1} /2 ≒ 2 mm, the size is smaller than that of the conventional cylindrical insulator that penetrates the side wall of the box inside and outside. As a result, the insulation properties do not deteriorate in any way, and the size of the switchgear can therefore be reduced. Furthermore, particularly in the second invention, the disconnecting portion is provided in the recessed portion of the cylindrical insulator filled with insulating gas, and the internally fixed conductor is inserted beyond the conductor insertion hole in the side wall of the box body into the recessed portion. The first invention can be achieved by setting the insertion dimension B of the internally fixed conductor into the cylindrical insulator as B≧g/5, and keeping the other conditions the same as the first invention. Similarly, the withstand voltage characteristics are well stabilized, and the disconnecting portion can be formed with smaller dimensions than before without deteriorating the insulation characteristics, allowing the switchgear to be further miniaturized.

[Brief explanation of drawings]

1 to 8 show the first to sixth embodiments of the present invention, and FIG. 1 is a cross-sectional view of the first embodiment of the portion where the conductor penetrates the side wall of the box body in gas-insulated electrical equipment; Fig. 2 is a sectional view of the second embodiment, Fig. 3 is a sectional view of Fig. 2, Fig. 4 is a sectional view of the third embodiment, Fig. 5 is a sectional view of the fourth embodiment, and Fig. 6. is a sectional view of FIG. 5, FIG. 7 is a sectional view of the fifth embodiment, FIG. 8 is a sectional view of the sixth embodiment, FIG. 9 is a schematic diagram of the switchgear shown as the first application example, and FIG. The figure is a schematic diagram of a switchgear shown as a second application example, Figure 11 is a cross-sectional view of an experimental model of a conductor penetration part in which a conductor is passed through a hole in a grounding plate in an insulating gas, and Figure 12 is a schematic diagram of a switchgear shown in Figure 11. Short-circuit voltage characteristic diagram, Figure 13 is a cross-sectional view of an experimental model of a conductor penetration part using a cylindrical insulator in close contact with the side wall of the grounding box and the conductor inserted through the hole in the side wall, Figure 14
The figure is the flash fault voltage characteristic diagram of Figure 13, and Figure 15 is the flash fault voltage characteristic diagram of Figure 1.
In the experimental model shown in Fig. 3, the flash fault voltage characteristic diagram when the inner diameter of the cylindrical insulator is increased is shown in Fig. 16.
Figures 17A and 17B are flash fault voltage characteristic diagrams for a mixture of SF ₆ gas and air. Two other experimental model cross-sectional views of conductor penetrations using closely-adhered cylindrical insulators, Figures 18A and B are the flash fault voltage characteristic diagrams of Figures 17A and B, and the first
Figure 9 is a flashover characteristic diagram in relation to the length of the inner wall of the cylindrical insulator in Figures 17A and B, and Figure 20 is a diagram showing the characteristics of a conductor with an end loosely fitted into the cylindrical insulator. 21 is a cross-sectional view of the experimental model; FIG. 21 is a flashover characteristic diagram for each dimension relationship in FIG. 20; FIG. 22 is a flashover characteristic diagram due to changes in dimension L in FIG. 23;
The figure is a cross-sectional view modeling the conventional wall-penetrating bushing shown in FIG. 24, FIG. 24 is a cross-sectional view of the conventional wall-penetrating bushing, and FIG. 25 is a schematic diagram of a switchgear to which the wall-penetrating bushing is applied. be. 2... Box side wall, 3... Conductor, 31... Internal fixed conductor, 32... Connection conductor, 4... Conductor insertion hole, 5... Box body, 9... Disconnection section, 11... Cylindrical insulator, l... Cylindrical insulator Length of inner end, φ ₁ ...Diameter of conductor insertion hole, g
...Length of the gap between the conductor and the conductor insertion hole, B...Dimension of insertion of the internally fixed conductor into the cylindrical insulator.

Claims (1)

[Scope of Claims] 1. Electrical equipment, conductors, etc. are housed in a box body, and insulating gas is filled in the box body, and a conductor is provided passing through the side wall of the box body, and the conductor is surrounded and the side wall is airtight. A gas-insulated electric device comprising a cylindrical insulator fixed to the box, the cylindrical insulator being provided on at least one side of a side wall of the box and configured so that gas exists inside the box; The gap dimension between the inner periphery of the conductor insertion hole provided in the body side wall and the conductor is g, the length dimension of the inner wall of the cylindrical insulator is l, the inner diameter dimension of the conductor insertion hole is φ ₁ , A gas-insulated electric device characterized in that, when the inner diameter dimension is φ ₂ , l≧g/4 and φ ₂ −φ ₁ /2 ≧2 mm. 2. A cylindrical box that houses electrical equipment and internal fixed conductors in a box body, fills insulating gas, and has an internal fixed conductor that penetrates the side wall of the box body, and that surrounds this conductor and is airtightly fixed to the side wall. In a gas-insulated electric device provided with an insulator, the cylindrical insulator is provided to protrude outside the side wall of the box body, and its inner recessed part is filled with insulating gas, and the end of the internal fixed conductor is provided with a cylindrical insulator. A connecting conductor is provided loosely through a conductor insertion hole in the side wall of the box body so as to be located inside the cylindrical insulator, and can freely come into contact with and separate from the internal fixed conductor, penetrate the cylindrical insulator in an airtight manner, and is movable in the axial direction. A disconnection section between the connecting conductor and the internal fixed conductor is formed in the cylindrical insulator, and the gap dimension between the inner periphery of the insertion hole provided in the side wall of the box body and the internal fixed conductor is g, When the length of the inner wall of the insulator is l, the inner diameter of the conductor insertion hole is _φ1 , the inner diameter of the cylindrical insulator is _φ2 , and the insertion dimension of the internal fixed conductor into the cylindrical insulator is B. , l≧g/4, φ ₁ −φ ₁ /2≧2mm, and B≧g/5.