Vacuum valve

Abstract

To solve the problem in which, when an insulating coating is formed to cover the entire vacuum vessel of a vacuum valve, the heat dissipation of a vacuum circuit breaker deteriorates.SOLUTION: A vacuum valve (1) includes a vacuum container (2), a fixed-side energized shaft (3), and an insulating covering member (6) that covers the fixed-side energized shaft and the vacuum container over a portion of an area in the longitudinal direction from the fixed-side energized shaft (3) to the vacuum container (2).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to vacuum valves. [Background technology]

[0002] Patent Document 1 discloses a vacuum circuit breaker in which an insulating coating made of an epoxy resin mixture is formed to cover the vacuum interrupting chamber in order to improve the insulating performance of the outer surface of the vacuum circuit breaker. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication 2009-505373 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if an insulating coating is formed so as to cover the entire vacuum vessel of the vacuum interrupter, the heat dissipation performance of the vacuum interrupter will be reduced. [Means for solving the problem]

[0005] In order to solve the above problems, a vacuum valve according to one embodiment of the present disclosure comprises a vacuum vessel, a fixed current-carrying shaft fixed to the vacuum vessel, and an insulating covering member that covers the fixed current-carrying shaft and the vacuum vessel from the fixed current-carrying shaft to a portion of the longitudinal region of the vacuum vessel. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, heat dissipation can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a main configuration of a vacuum interrupter according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a visual diagram of the electric field strength distribution measured along the length of the first portion. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment 1] A first embodiment of the present disclosure will be described in detail below with reference to Fig. 1. Fig. 1 is a diagram illustrating the configuration of the main parts of a vacuum interrupter 1 according to the first embodiment. In the following description, a vacuum interrupter applied to a current interruption equipment for electric power, such as a vacuum circuit breaker or a vacuum switchgear, will be used as an example. However, the vacuum interrupter of the present disclosure can also be applied to vacuum interrupters used in other electric power equipment, such as substation equipment.

[0009] As shown in FIG. 1, the vacuum interrupter 1 of this embodiment includes a vacuum vessel 2, a fixed-side current-carrying shaft 3, a movable-side current-carrying shaft 4, a resin composition 5, and a covering member 6.

[0010] The vacuum vessel 2 is a vessel whose interior is maintained at a predetermined vacuum level. The vacuum vessel 2 is composed of, for example, a cylindrical main body 21 and a fixed-side lid 22 and a movable-side lid 23 that airtightly seal the openings at both ends of the main body. The vacuum vessel 2 is also composed of an insulating material, such as ceramic.

[0011] The fixed-side current-carrying shaft 3 is a conductor fixed to the vacuum vessel 2. The fixed-side current-carrying shaft 3 electrically connects the above-mentioned power interruption equipment with a fixed-side contact (not shown) provided inside the vacuum vessel 2. The fixed-side current-carrying shaft 3, for example, passes through the fixed-side lid 22 and is airtightly attached to the fixed-side lid 22 by welding such as brazing. The fixed-side current-carrying shaft 3 is made of a conductor, for example, made of a metal such as copper.

[0012] The movable current-carrying shaft 4 is a conductor that is provided so as to be movable relative to the vacuum vessel 2. The movable current-carrying shaft 4 electrically connects the above-mentioned power interruption equipment with a movable contact (not shown) provided inside the vacuum vessel 2. The movable current-carrying shaft 4 is attached so as to be movable and airtight relative to the vacuum vessel 2, for example, via a bellows (not shown) fixed to the surface of the movable side cover 23. The movable current-carrying shaft 4 is made of a conductor, for example, made of a metal such as copper.

[0013] The fixed contact and the moving contact described above form a pair of contacts that are provided inside the vacuum vessel 2 and can be brought into contact with and separated from each other. When the vacuum valve 1 is opened, the fixed contact and the moving contact are separated from each other. When the vacuum valve 1 is closed, the fixed contact and the moving contact are brought into contact with each other, allowing current to flow when the electric circuit is connected. The fixed contact and the moving contact are made of a material that is as resistant as possible to arc discharge that occurs when the electric circuit is interrupted. The fixed contact and the moving contact are made of a metal such as a copper-chromium alloy (Cu-Cr).

[0014] The covering member 6 covers the fixed-side current-carrying shaft 3 and the vacuum vessel 2 from the fixed-side current-carrying shaft 3 to a portion of the longitudinal region of the vacuum interrupter 1. As shown in Fig. 1, the covering member 6 includes a first portion 61 that covers the side surface of the vacuum vessel 2, a second portion 62 that covers the side surface of the fixed-side current-carrying shaft 3, and a third portion 63 that connects the first portion 61 and the second portion 62 and covers the top surface of the fixed-side cover 22. The covering member 6 is made of an insulating material, for example, a ceramic such as alumina or a resin such as epoxy resin.

[0015] When the entire vacuum vessel is covered with an insulating coating, as in the prior art, the insulating performance of the outer surface is improved, which reduces the occurrence of flashover from the fixed current-carrying shaft to the movable current-carrying shaft. However, covering the entire surface of the vacuum vessel reduces the heat dissipation performance of the vacuum vessel, which increases the risk of damage to the vacuum valve.

[0016] The vacuum interrupter 1 according to the first embodiment has the covering member 6, which reduces the electric field strength generated from the fixed-side current-carrying shaft 3 and improves insulation performance. The covering member 6 also covers the fixed-side current-carrying shaft 3 and the vacuum vessel 2 from the fixed-side current-carrying shaft 3 to a portion of the longitudinal region of the vacuum vessel 2. In other words, a portion of the vacuum vessel 2 is exposed and not covered by the covering member 6. This allows heat to be dissipated directly from the exposed portion into the surrounding air, improving heat dissipation performance.

[0017] The first portion 61 covers a portion of the side surface of the vacuum vessel 2 on the side of the fixed-side current-carrying shaft 3. In the present disclosure, the longitudinal length of the first portion 61 varies depending on the specifications and dimensions of the vacuum valve, the voltage applied to the vacuum valve, and other conditions. Therefore, the length of the first portion 61 may be set arbitrarily. For example, the longitudinal length of the first portion 61 may be 20% to 50% of the longitudinal length of the vacuum vessel 2. More specifically, for example, when a rated voltage of 33 kV is applied to a vacuum valve 1 having a vacuum vessel 2 with an axial length of 235 mm and a diameter of 132 mm, the length of the first portion 61 may be 70 mm to 125 mm.

[0018] The first portion 61 extends in the axial direction from the side surface of the fixed-side lid 22 of the vacuum vessel 2 toward the movable-side current-carrying shaft 4. The first portion 61 includes a tapered portion 611 and an edge 612. The edge 612 is the end of the first portion 61 on the movable-side current-carrying shaft 4 side. The tapered portion 611 has a tapered structure in which its thickness decreases with increasing distance from the fixed-side current-carrying shaft 3. The thinnest point of the tapered portion 611 coincides with the edge 612.

[0019] Since the first portion 61 has the tapered portion 611, the electric field strength concentrated at the edge 612 can be reduced, thereby reducing the electric field strength and improving the insulation performance compared to when the first portion 61 does not have a tapered structure.

[0020] The second portion 62 is located on the side of the fixed-side current-carrying shaft 3 located outside the vacuum vessel 2. In Fig. 1, notches are provided in parts of the fixed-side current-carrying shaft 3 and the second portion 62, but in reality, the notches may or may not be present. The second portion 62 has a protrusion 64.

[0021] The protrusion 64 extends in the circumferential direction of the second part 62 and protrudes from the second part. As shown in Fig. 1, the protrusion 64 extends perpendicular to the axial direction of the vacuum valve 1, but the angle formed between the extension direction of the protrusion 64 and the axial direction of the vacuum valve 1 may be any angle.

[0022] Providing the protrusion 64 on the covering member 6 increases the creepage distance, which is the path of flashover, improving insulation performance. Furthermore, if the vacuum interrupter is used in an environment where dust (dirt, iron powder) is present or where humidity is high, flashover may occur via dust adhering to the surface of the vacuum interrupter. Providing the protrusion 64 on the vacuum interrupter 1 forms a portion on the covering member 6 where foreign matter is less likely to adhere, reducing the occurrence of flashover.

[0023] The "portion where foreign matter is less likely to adhere" refers to, for example, the lower corner of the corner formed by the second portion 62 and the protruding portion 64 when the movable-side current-carrying shaft 4 is positioned below and the fixed-side current-carrying shaft 3 is positioned above. In this case, the protruding portion 64 acts as a canopy, making it difficult for foreign matter to adhere to the corner.

[0024] Furthermore, in the above configuration, the covering member 6 is provided with one protrusion 64. For example, if multiple protrusions 64 are provided and the protrusions 64 are close to each other, flashover is more likely to occur from the outer edge of one protrusion 64 to the outer edge of an adjacent protrusion 64. On the other hand, if the protrusions 64 are spaced far enough apart to reduce the occurrence of flashover, the axial length of the vacuum interrupter 1 becomes longer. By providing only one protrusion 64, the axial length of the vacuum interrupter 1 can be reduced while reducing the occurrence of flashover compared to when multiple protrusions 64 are provided.

[0025] If the axial length of the vacuum valve 1 can be long, one or more protrusions 64 may be provided.

[0026] The second portion 62 is smaller than the diameter of the vacuum vessel 2 centered on the axis of the vacuum interrupter 1, and this forms a third portion 63 of the covering member 6 that covers the upper surface of the vacuum vessel 2, which corresponds to the lid. As shown in Figure 1, the third portion 63 is stepped and has a surface parallel to the fixed-side lid 22, and the covering member 6 has a shape that roughly follows the contours of the fixed-side current-carrying shaft 3 and the vacuum vessel 2.

[0027] The third portion 63 extends in the radial direction, thereby increasing the creepage distance and improving the insulation performance.

[0028] Furthermore, when comparing the third portion 63 and the protruding portion 64, when viewed from the axial direction of the vacuum interrupter 1, i.e., when viewed from above, the protruding portion 64 extends further outward than the third portion 63. In light of the above-described configuration, the protruding portion 64 extends furthest outward in the vacuum interrupter 1.

[0029] The large radial length of the protrusion 64 reduces adhesion of foreign matter to the second part 62 and the third part 63 located below the protrusion 64, thereby increasing the area where foreign matter is less likely to adhere, thereby improving insulation performance.

[0030] 1, the vacuum valve 1 further includes a resin composition 5. The resin composition 5 is a resin that is filled between the covering member 6 and the vacuum vessel 2. The resin composition 5 has insulating properties, and examples of the resin composition include silicone resin and epoxy resin.

[0031] By providing an insulating resin composition 5 between the vacuum vessel 2 and the covering member 6, the gap between the vacuum vessel 2 and the covering member 6 is filled, thereby reducing flashover between the vacuum vessel 2 and the covering member 6.

[0032] [Measurement of electric field strength] The results of examining the length of the first portion 61 will be described below with reference to Fig. 2. For the sake of convenience, the description of members having the same functions as those described in the above embodiment will not be repeated.

[0033] Fig. 2 shows the results of measuring the electric field strength distribution for a vacuum interrupter having four covering members with different lengths of first portion 61. In Fig. 2, along with the vacuum interrupter 1 according to embodiment 1, vacuum interrupters 1B and 1C, which are other embodiments, and vacuum interrupter 1A, which is a comparative example, are shown, and electric field distributions E, EA, EB, and EC correspond to the vacuum interrupters 1, 1A, 1B, and 1C, respectively.

[0034] The dimensions of the vacuum vessel 2 used in the measurement were an axial length of 235 mm and a diameter of 132 mm. Furthermore, a voltage of 33 kV was applied to the fixed side current-carrying shaft 3 at this time.

[0035] The covering member of the vacuum valve 1B, which is another embodiment, includes a first portion 61B. The covering member of the vacuum valve 1C includes a first portion 61C. The first portion 61, the first portion 61B, and the first portion 61C have different axial lengths. The vacuum valve 1A does not include a portion corresponding to the first portion 61.

[0036] The axial lengths of the first portions 61, 61A, 61B, and 61C are as follows: the length of the first portion 61 is 70 mm, the length of the first portion 61B is 26 mm, and the length of the first portion 61C is 45 mm.

[0037] Comparing the electric field distribution EA with the electric field distributions E, EB, and EC, it is found that the electric field strength of the electric field distribution EA has a larger range of higher values ​​than the electric field strengths of the electric field distributions E, EB, and EC. Therefore, it has been demonstrated that by providing a vacuum interrupter with a covering member including the first portion, the electric field strength can be reduced, and the occurrence of flashover can be reduced.

[0038] Furthermore, when comparing the electric field distributions E, EB, and EC, the electric field strength near the edges of first portion 61B and first portion 61C exceeds 1.350% / mm, whereas no areas exceeding 1.350% / mm were observed in electric field distribution E. This demonstrates that the occurrence of flashover can be further reduced by setting the longitudinal length of first portion 61 to be between 20% and 50% of the longitudinal length of vacuum vessel 2. Note that the electric field strength [% / mm] here represents the voltage per unit length expressed in units of pu.

[0039] It should be noted that only the vacuum valve 1A does not have a part equivalent to the protrusion 64, but the protrusion 64 is a component provided to reduce flashover that occurs between the notch in the second part 62 and the outer edge of the third part 63. On the other hand, the measurement in Figure 2 is an experiment to measure the electric field strength E at the edge 612, so the presence or absence of the protrusion 64 was ignored in this measurement.

[0040] [Flashover generation experiment] An experiment was conducted to check the occurrence of flashover in a vacuum interrupter under arbitrary conditions. First, an experiment was conducted to check the occurrence of flashover in a vacuum interrupter 1 according to the present disclosure and a vacuum interrupter without a covering member 6. As experimental conditions, the dimensions of the vacuum vessels used for measurement were an axial length of 235 mm and a diameter of 132 mm. In addition, in the vacuum interrupter 1, the axial length of the first portion 61 of the covering member 6 was 80 mm. A voltage was applied to each fixed-side current-carrying shaft 3, and it was observed whether flashover occurred when an arbitrary voltage was applied.

[0041] As a result of the experiment, a flashover occurred at 126 kV in the vacuum interrupter without the covering member 6. On the other hand, no flashover occurred even at 150 kV in the vacuum interrupter 1. This experiment demonstrated that the vacuum interrupter 1 according to the present disclosure can significantly reduce the possibility of a flashover compared to a vacuum interrupter without the covering member 6.

[0042] Next, an experiment was conducted to check the occurrence of flashover in a vacuum interrupter 1 having a covering member with a protrusion 64, and a vacuum interrupter 1 having a covering member 6 without a protrusion 64. The radial length of the protrusion 64 was 31 mm from the surface of the second portion 62. The two covering members had the same shape except for the protrusion 64.

[0043] As a result of the experiment, a flashover occurred at 126 kV in the vacuum interrupter 1 without the protrusion 64. On the other hand, no flashover occurred even at 150 kV in the vacuum interrupter 1 with the protrusion 64. This experiment demonstrated that the presence of the protrusion 64 can significantly reduce the possibility of a flashover.

[0044] Furthermore, an experiment was conducted on the occurrence of flashover in a vacuum interrupter equipped with a covering member made of epoxy resin that covers only the periphery of the fixed-side current-carrying shaft 3.

[0045] As a result of the experiment, when 142 kV was applied, a flashover occurred through the resin composition 5 between the covering member and the vacuum vessel 2 .

[0046] The above experiment demonstrated that the vacuum interrupter 1 equipped with the first portion 61 has improved insulation performance. 〔summary〕 A first aspect of the vacuum valve according to the present disclosure comprises a vacuum vessel, a fixed current-carrying shaft fixed to the vacuum vessel, and an insulating covering member that covers the fixed current-carrying shaft and the vacuum vessel from the fixed current-carrying shaft to a portion of the longitudinal region of the vacuum vessel.

[0047] A second aspect of the vacuum valve according to the present disclosure is the same as the first aspect, except that a resin composition is filled between the covering member and the vacuum vessel.

[0048] A third aspect of the vacuum valve according to the present disclosure is either of the first or second aspects, in which the covering member has a first portion that covers the side surface of the vacuum vessel, and the thickness of the first portion becomes thinner with increasing distance from the fixed side current-carrying shaft.

[0049] A fourth aspect of the vacuum valve according to the present disclosure is any one of the first to third aspects, wherein the covering member has a second portion that covers the side surface of the fixed side current-carrying shaft, and the second portion has one or more protrusions extending circumferentially.

[0050] A fifth aspect of the vacuum valve according to the present disclosure is the fourth aspect, in which the number of the protrusions is one.

[0051] A sixth aspect of the vacuum valve according to the present disclosure is any one of the fourth or fifth aspects, in which the diameter of the second portion is smaller than the diameter of the vacuum vessel, and the covering member has a third portion that covers the upper surface of the vacuum vessel.

[0052] A seventh aspect of the vacuum interrupter according to the present disclosure is any one of the fourth to sixth aspects, wherein the outer edge of the protrusion is positioned outside the outer edge of the vacuum vessel in top view.

[0053] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0054] 1, 1B, 1C vacuum valve 2 Vacuum container 3 Fixed side current-carrying shaft 4 Movable side current-carrying shaft 5 Resin composition 6 Covering material 61, 61B, 61C Part 1 62 Part 2 63 Part 3 64 Protrusion 611 Tapered section 612 Edge E, EB, EC electric field distribution

Claims

1. A vacuum vessel; a fixed current-carrying shaft fixed to the vacuum vessel; a covering member that covers the fixed-side current-carrying shaft and the vacuum vessel from the fixed-side current-carrying shaft to a portion of the longitudinal direction of the vacuum vessel.

2. The vacuum valve according to claim 1 , further comprising a resin composition filled between the covering member and the vacuum vessel.

3. 2. The vacuum valve according to claim 1, wherein the covering member has a first portion that covers the side surface of the vacuum vessel, and the thickness of the first portion decreases with increasing distance from the fixed-side current-carrying shaft.

4. the covering member has a second portion that covers a side surface of the fixed-side current-carrying shaft, The vacuum valve of claim 1 , wherein the second portion comprises one or more circumferentially extending protrusions.

5. The vacuum valve according to claim 4, wherein the number of said protrusions is one.

6. the diameter of the second portion is smaller than the diameter of the vacuum vessel; 5. The vacuum valve according to claim 4, wherein the covering member has a third portion that covers an upper surface of the vacuum vessel.

7. 7. The vacuum valve according to claim 6, wherein an outer edge of the protrusion is located outside an outer edge of the vacuum vessel in a top view.

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