Defect detection method and vacuum circuit breaker

Abstract

To provide a defect detection method capable of continuously detecting a defect.SOLUTION: A defect detection method detects a defect in a vacuum valve (1) which is installed in a vacuum circuit breaker (100) and used to interrupt a cable run, in accordance with a luminescence state of a stress luminescent material (10) applied on a surface of the vacuum valve.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fault detection method and a vacuum circuit breaker. [Background technology]

[0002] Patent Document 1 discloses a method of detecting vacuum leaks in a vacuum valve housed in a gas-insulated cubicle filled with SF6 gas, in which a withstand voltage is applied to a vacuum valve having a predetermined gap length between its contacts, and the presence or absence of a vacuum leak of SF6 gas is detected from the gap length and the dielectric breakdown voltage value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-086696 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-mentioned conventional technology, detecting the presence or absence of vacuum leaks in vacuum valves requires periodic disassembly inspections after shutting down the gas-insulated cubicle and power equipment, making it impossible to immediately detect the occurrence of vacuum leaks. Furthermore, the inspection work requires the use of a separate high-voltage testing machine, which makes the inspection work time-consuming.

[0005] An object of one aspect of the present invention is to realize continuous defect detection with a simple configuration. [Means for solving the problem]

[0006] There is a causal relationship in which, when a defect occurs in a vacuum valve, the atmosphere around the vacuum valve may flow into the vacuum valve through the defect, causing a vacuum leak. The inventors focused on this causal relationship and, in order to solve the above-mentioned problem, came up with the idea of ​​detecting a defect in a vacuum valve based on the luminescence state of a mechanoluminescent material applied to the surface of a vacuum valve that is installed in a vacuum circuit breaker installed in electric power equipment and that interrupts an electric circuit, according to one aspect of the present invention. Detecting a defect in a vacuum valve in this way makes it possible to detect a vacuum leak. [Effects of the Invention]

[0007] According to one aspect of the present invention, a stress-stimulated luminescent material is applied to the surface of a vacuum valve. The luminescence intensity of the stress-stimulated luminescent material changes depending on the magnitude of changes in the force and strain applied to the material. Therefore, the luminescence state differs between defective and non-defective areas of the vacuum valve. Therefore, based on the luminescence state of the stress-stimulated luminescent material, defects in the vacuum valve can be detected. Furthermore, the simple configuration of applying the stress-stimulated luminescent material to the surface of the vacuum valve enables continuous defect detection. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a vacuum interrupter according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a schematic diagram of a vacuum interrupter according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment 1] An embodiment of the present disclosure will be described in detail below with reference to Fig. 1. A defect detection method according to the present disclosure includes a vacuum circuit breaker 100 shown below. Fig. 1 is a schematic diagram of the vacuum circuit breaker 100 according to an embodiment of the present disclosure. Note that in the following description, the vacuum circuit breaker 100 will be described as including a vacuum valve installed in high-voltage power equipment, but the vacuum circuit breaker of the present disclosure can also be applied to vacuum circuit breakers used in other power equipment such as substation equipment.

[0010] 1, the vacuum circuit breaker 100 of this embodiment includes a vacuum interrupter 1 and a detection unit 30. Although not shown, an insulating gas (e.g., SF6 gas) is sealed inside the vacuum circuit breaker 100 and around the vacuum interrupter 1.

[0011] The vacuum interrupter 1 interrupts an electric circuit. As shown in Fig. 1, the vacuum interrupter 1 includes a vacuum vessel 20 having a surface coated with a mechanoluminescent material 10. The vacuum vessel 20 also includes two lids 21, an insulating tube 22, a first conductor 24, a second conductor 26, and a shield 27. The interior of the vacuum vessel 20 is maintained at a predetermined vacuum level.

[0012] The first conductor 24 and the second conductor 26 are each a conductor having a columnar portion. The columnar portion of the first conductor 24 and the columnar portion of the second conductor 26 are arranged coaxially. The first conductor 24 may be fixed to the vacuum vessel 20 while the second conductor 26 is provided to be movable relative to the vacuum vessel 20, or the second conductor 26 may be fixed to the vacuum vessel 20 while the first conductor 24 is provided to be movable relative to the vacuum vessel 20.

[0013] The first conductor 24 has a first electrode 23 at one end, and the other end protrudes from the vacuum vessel 20 and is connected to an electric circuit of the power equipment. The first conductor 24 and the first electrode 23 are made of a metal such as copper. The first conductor 24 is inserted into the lid 21 described below and is airtightly attached by brazing or the like. In addition, a reinforcing member may be provided on the lid 21 to fix the first conductor 24 to the vacuum vessel 20.

[0014] The second conductor 26 has a second electrode 25 at one end, and the other end protrudes from the vacuum vessel 20 and is connected to an electric circuit of the power equipment. The second conductor 26 and the second electrode 25 are made of a metal such as copper. A drive mechanism (not shown) is connected to the second conductor 26, and the second conductor 26 can be moved by the drive device in a direction that allows it to be separated from the first conductor 24 (the direction opposite to the contact point with the first electrode 23). The second conductor 26 is movably and airtightly attached to the lid 21, for example, via a bellows fixed to the surface of the lid 21.

[0015] The first electrode 23 and the second electrode 25 are a pair of electrodes that come into contact with or are separated from each other inside the insulating tube 22, constituting a pair of contacts that are capable of coming into and out of contact with each other. Furthermore, when the vacuum valve 1 is closed, the first electrode 23 and the second electrode 25 come into contact with each other to form an electrical path that electrically connects the first conductor 24 and the second conductor 26, allowing current to flow. Furthermore, the first electrode 23 and the second electrode 25 are separated from each other when the vacuum valve 1 is opened.

[0016] The insulating tube 22 is an insulating part that insulates the vacuum vessel 20 so that the first conductor 24 and the second conductor 26 are not electrically connected except when the first electrode 23 and the second electrode 25 are in contact with each other. In other words, when the first electrode 23 and the second electrode 25 are separated from each other, the presence of the insulating tube 22 on the side surface of the vacuum valve 1 electrically disconnects the first conductor 24 and the second conductor 26. This breaks the electrical path electrically connecting the first conductor 24 and the second conductor 26. The insulating tube 22 is made of an insulating material, which may be, for example, ceramics.

[0017] The insulating tube 22 constitutes a cylindrical vacuum vessel body to accommodate the first electrode 23 and the second electrode 25, and is disposed coaxially with the first conductor 24 and the second conductor 26. Although the insulating tube 22 is formed from a single cylindrical member, it may be separable into a fixed contact side and a moving contact side.

[0018] The lid 21 airtightly seals the opening on the fixed contact side and the opening on the moving contact side of the insulating cylinder 22, and is configured to allow the first conductor 24 or the second conductor 26 to be inserted therethrough. The lid 21 may be made of a metal material such as stainless steel.

[0019] The vacuum interrupter 1 also includes a shield 27. The shield 27 surrounds and covers the first electrode 23 and the second electrode 25 along the axial direction, with a portion of the shield 27 connected to the inner wall of the insulating tube 22. Even when the first electrode 23 and the second electrode 25 are partially melted by the arc discharge and scattered as metal vapor, the shield 27 prevents the scattered material containing the metal vapor from scattering and adhering to the surrounding insulating tube 22.

[0020] The outer surface of the vacuum vessel 20 is coated with a stress-stimulated luminescent material 10. The stress-stimulated luminescent material 10 contains a powder or particulate stress-stimulated luminescent material, and the stress-stimulated luminescent material contained in the stress-stimulated luminescent material 10 emits light in response to stress acting on the material itself. The stress-stimulated luminescent material 10 also emits light with an intensity proportional to the magnitude of the stress. Therefore, the change from areas of high stress to areas of low stress can be recognized as a gradation indicated by the strength of the luminescence intensity, and the magnitude of the stress can be determined from the strength of the luminescence. Furthermore, if a crack occurs on the outer surface of the vacuum vessel 20 coated with the stress-stimulated luminescent material 10, a particularly strong luminescence is emitted.

[0021] The mechanoluminescent material is an inorganic material whose main components are strontium (Sr), europium (Eu), and aluminum oxide (AlO4). The mechanoluminescent material 10 may be prepared as a paint in which the mechanoluminescent material is mixed into an existing paint.

[0022] The detection unit 30 detects the luminescence of the stress-luminescent material 10 applied to the surface of the vacuum interrupter 1 and determines the state of the vacuum interrupter 1 from the state of luminescence. For example, when stress is generated in the vacuum interrupter 1 due to vibrations accompanying the opening and closing operation of the vacuum interrupter 100, the detection unit 30 can detect the occurrence of stress. Furthermore, when a defect such as a crack occurs on the surface of the vacuum interrupter 1 or peeling of the solder sealing the cover 21 and the insulating tube 22, the detection unit 30 can detect the luminescence accompanying the occurrence of the defect.

[0023] According to the above configuration, it is possible to immediately detect any defects by constantly detecting the stress-luminescence state of the vacuum valve 1 in the detection unit 30. Furthermore, since there is no need to shut down the power equipment for periodic inspection work as in the prior art, the labor required for inspection work can be reduced.

[0024] The stress-luminescent material 10 may be applied to any area of ​​the vacuum interrupter 1. By applying the stress-luminescent material 10 to the area where it is desired to detect defects, defects can be uniformly detected within the applied area. The wider the applied area, the wider the area in which defects can be detected.

[0025] Furthermore, the stress-luminescent material 10 is applied to the entire outer surface of the insulating tube 22. If a defect occurs in the insulating tube 22, this defect may cause a sudden vacuum leak in the vacuum interrupter 1. Therefore, by constantly detecting defects in the insulating tube 22 using this configuration, it is possible to quickly take action if a defect occurs.

[0026] The detection unit 30 is connected to a camera 31. The camera 31 detects the luminescence of the stress-stimulated luminescent material 10 and captures the luminescence. The camera 31 may be located anywhere as long as it can capture an image of the vacuum interrupter 1, and may be located inside or outside the vacuum interrupter 100. The detection unit 30 acquires the luminescence state of the stress-stimulated luminescent material 10 based on the image captured by the camera 31. The camera 31 is, for example, a CCD camera, and the detection unit 30 is capable of image processing. This allows the detection unit 30 to perform image processing on the image of the vacuum interrupter 1 captured by the camera 31 to identify the position, size, and shape of a location where a luminance change occurs compared to other locations. Furthermore, by previously obtaining the luminescence intensity of the stress-stimulated luminescent material 10 that occurs when a defect occurs in the vacuum interrupter 1, the detection unit 30 can also determine whether a defect actually exists in the location where a luminance change occurs, based on the luminance of the image captured by the camera 31.

[0027] According to the above configuration, the camera 31 captures an image, and the detection unit 30 can grasp the luminescence state of the stress-stimulated luminescent material 10 and accurately detect defects including their position, size, shape, and the like.

[0028] The detection unit 30 may include multiple cameras 31. For example, if the camera 31 is placed in a position where it can capture an image of the entire vacuum valve 1, the camera 31 can capture an image of the entire vacuum valve 1, and the detection unit 30 can detect defects that occur throughout the entire vacuum valve 1.

[0029] The vacuum circuit breaker 100 of the present disclosure may include a communication unit (not shown). The communication unit notifies a monitor in a remote location of data related to defects detected by the detection unit 30. The communication unit is connected to the Internet and can transmit data to a computer, tablet, or the like via the Internet. This allows for continuous detection and immediate notification when a defect occurs.

[0030] [Embodiment 2] Other embodiments of the present disclosure will be described below. For convenience of explanation, the same reference numerals will be used to designate components having the same functions as those described in the first embodiment, and the description thereof will not be repeated.

[0031] FIG. 2 is a schematic diagram of a vacuum circuit breaker 100 according to another embodiment of the present disclosure. Unlike FIG. 1, FIG. 2 does not visualize the internal structure. The vacuum circuit breaker 100 includes a vacuum interrupter 1 and a detection unit 30. The vacuum interrupter 1 includes a stress-luminescent material 10 and a vacuum vessel 20. The vacuum vessel 20 includes two lids 21, an insulating tube 22, a first conductor 24, a second conductor 26, and a shield 27 (not shown). Although not shown in FIG. 2, the first conductor 24 includes a first electrode 23, and the second conductor 26 includes a second electrode 25.

[0032] The detection unit 30 is connected to a luminance sensor 31A. The luminance sensor 31A detects the luminance of the light emitted by the stress-stimulated luminescent material 10. The luminance sensor 31A may be located at any position where it can detect the luminescence of the stress-stimulated luminescent material applied to the vacuum vessel 20, and may be located inside or outside the vacuum circuit breaker 100. The luminance sensor 31A detects the luminance of the stress-stimulated luminescent material 10 to obtain the luminous state of the stress-stimulated luminescent material 10.

[0033] According to the above configuration, the detection unit 30 constantly monitors the stress-luminescence state of the vacuum valve 1 based on the brightness obtained from the brightness sensor 31A, making it possible to immediately detect any defects that may occur. Furthermore, unlike conventional technology, there is no need to shut down the power equipment for periodic inspection work, which reduces the labor required for inspection work. Furthermore, brightness sensors are generally less expensive than cameras, which reduces costs.

[0034] The detection unit 30A may include multiple brightness sensors 31A. For example, if the brightness sensor 31A is placed in a position where it can detect the entire vacuum interrupter 1, the brightness sensor 31A can detect the entire vacuum interrupter 1, and the detection unit 30A can detect defects that occur throughout the entire vacuum interrupter 1.

[0035] 〔summary〕 A defect detection method according to aspect 1 of the present disclosure is installed in a vacuum circuit breaker provided in an electric power facility, and detects defects in the vacuum valve based on the luminescence state of a stress-luminescent material applied to the surface of the vacuum valve that interrupts an electric circuit.

[0036] A defect detection method according to aspect 2 of the present disclosure is a method in which, in aspect 1, the vacuum valve comprises a cylindrical insulating portion and a pair of electrodes that are in contact with or spaced apart from each other inside the insulating portion, the pair of electrodes forming the electrical path when in contact with each other and interrupting the electrical path together with the insulating portion when spaced apart, and the stress-luminescent material is applied to the outer surface of the insulating portion.

[0037] A defect detection method according to a third aspect of the present disclosure is the same as that of the first or second aspect, in which the luminescence state of the stress-stimulated luminescent material is obtained from an image of the stress-stimulated luminescent material taken with a camera.

[0038] A defect detection method according to a fourth aspect of the present disclosure is any one of the first to third aspects, in which the luminance of the stress-stimulated luminescent material is detected by a luminance sensor to obtain the luminous state of the stress-stimulated luminescent material.

[0039] A defect detection method according to aspect 5 of the present disclosure is a vacuum circuit breaker that is installed in an electric power facility and includes a vacuum valve that interrupts an electrical circuit, wherein a stress-luminescent material is applied to the surface of the vacuum valve and a detection unit is provided that detects defects in the vacuum valve based on the luminescent state of the stress-luminescent material.

[0040] The present invention 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 invention. [Explanation of symbols]

[0041] 100 Vacuum Circuit Breaker 1 vacuum valve 10 Stimuli-luminescent materials 20 Vacuum container 21 Lid 22 Insulating tube 23 1st electrode 24 First Conductor 25 2nd electrode 26 Second Conductor 27 Shield 30 Detector 31 Camera 31A Brightness Sensor

Claims

1. A defect detection method for detecting defects in a vacuum valve, which is installed in a vacuum circuit breaker installed in an electric power facility and interrupts an electric circuit, based on the luminescence state of a stress-luminescent material applied to the surface of the vacuum valve.

2. The vacuum valve includes a cylindrical insulating portion and a pair of electrodes that are in contact with or spaced apart from each other inside the insulating portion, the pair of electrodes form the electric path when in contact with each other, and interrupt the electric path together with the insulating portion when separated from each other, The defect detection method according to claim 1 , wherein the stress-luminescent material is applied to an outer surface of the insulating portion.

3. The defect detection method according to claim 1 , wherein the luminescence state of the stress-stimulated luminescent material is obtained from an image of the stress-stimulated luminescent material taken with a camera.

4. The defect detection method according to claim 1 , wherein the luminance of the stress-stimulated luminescent material is detected by a luminance sensor to obtain the luminous state of the stress-stimulated luminescent material.

5. A vacuum circuit breaker that is provided in an electric power facility and has a vacuum valve that interrupts an electric circuit, The surface of the vacuum valve is coated with a stress-luminescent material, a detecting unit that detects a defect in the vacuum interrupter based on the luminous state of the stress-luminescent material.

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