Vacuum arc-extinguishing chamber vacuum degree monitoring assembly and monitoring method thereof

Abstract

The invention discloses a vacuum arc extinguish chamber vacuum degree monitoring assembly and a monitoring method thereof, and belongs to the technical field of vacuum circuit breakers, the monitoring assembly comprises a measuring cavity arranged in a static conducting rod, the measuring cavity is communicated with an inner cavity of an insulating ceramic shell through a communicating hole, and an oxygen-sensitive sensor and a heating device are installed in the measuring cavity; a ceramic insulating plate is installed on the static end cover plate, the ceramic insulating plate is provided with an exposing opening for exposing the static conducting rod and the static end conducting block, and connecting wires of the oxygen-sensitive sensor and the heating device extend into the ceramic insulating plate and extend out of the side wall. The monitoring method comprises the following steps: S1, arranging the monitoring assembly on the vacuum arc-extinguishing chamber; s2, a heating device is started, and the temperature is adjusted to the working temperature of the oxygen-sensitive sensor; and S3, starting the measuring device, and receiving monitoring data of the oxygen-sensitive sensor. The online monitoring of the vacuum degree of the vacuum arc-extinguishing chamber can be realized, the detection precision is high, the vacuum degree detection range is wide, and disturbance and loss caused by exit and access of equipment in offline detection are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum circuit breakers, and in particular to a vacuum degree monitoring component for a vacuum interrupter and a monitoring method thereof. Background Art

[0002] The vacuum interrupter is the core component of medium and high voltage power switches. Its main function is to quickly extinguish the arc when the vacuum circuit breaker is disconnected through the excellent insulation of the high vacuum inside the tube, avoiding accidents and unexpected events. The Ministry of Standards (JB) stipulates that the maximum allowable pressure inside the vacuum interrupter is 1.33×10 -2 Pa, when the pressure inside the vacuum interrupter is higher than this value, it means that the vacuum inside the vacuum interrupter is seriously deteriorated, affecting the breaking capacity of the vacuum interrupter. In severe cases, breakdown may even occur, making the line unable to operate normally. In practical application fields, it is urgent to measure the vacuum degree of the vacuum interrupter. The existing circuit breaker vacuum degree detection technology is divided into two categories: offline detection and online detection.

[0003] The more mature detection methods in offline detection are the power frequency withstand voltage method and the pulse magnetron discharge method. However, the power frequency withstand voltage method requires the vacuum circuit breaker to be in a shutdown state and can only detect the vacuum degree qualitatively. The arc extinguishing chamber with a vacuum degree lower than the operating standard can still pass the withstand voltage test. Although the pulse magnetron discharge method can quantitatively detect the vacuum degree, the arc extinguishing chamber needs to be removed from the circuit breaker and placed in the electromagnetic coil during detection, that is, both methods will affect the normal use of the vacuum circuit breaker. The more mature detection methods in online detection are the coupling capacitor method. The coupling capacitor method is based on the principles of dynamic charge distribution and capacitive voltage division. When the vacuum degree changes, the distributed capacitance between the contact and the shielding cover and the distributed capacitance between the shielding cover and the induction electrode will change. Since the coupling capacitor is connected in series with the distributed capacitance, the coupling capacitor voltage will change. The vacuum degree can be detected online by measuring the coupling capacitor voltage. Although this method will not affect the normal use of the vacuum circuit breaker, its detection accuracy is low and can only reach 10 -1 ~10 -2 Pa. Summary of the invention

[0004] The purpose of the present invention is to solve the above technical problems and provide a vacuum degree monitoring component and a monitoring method for a vacuum interrupter. By setting a measuring cavity connected to the interior of the interrupter in a static conductive rod and detecting the oxygen content in the vacuum interrupter by an oxygen sensitive sensor in the measuring cavity, online monitoring of the vacuum degree of the vacuum interrupter can be achieved. The detection has high accuracy and a wide detection range, and the problem of offline detection causing the vacuum circuit breaker to be taken out of operation and affect normal use is avoided.

[0005] To achieve the above-mentioned purpose, the present invention provides the following scheme: The present invention discloses a vacuum degree monitoring component for a vacuum interrupter, comprising a measuring cavity arranged in a static conductive rod of the vacuum interrupter, the measuring cavity being connected with the internal cavity of an insulating ceramic shell of the vacuum interrupter through a connecting hole, an oxygen sensitive sensor and a heating device being installed in the measuring cavity, a ceramic insulating plate being installed on the static end cover of the vacuum interrupter, the ceramic insulating plate and the static conductive rod extending out of one end of the static end cover being fitted together, an exposure opening being provided on the ceramic insulating plate for exposing the static conductive rod and the static end conductive block, the wiring of the oxygen sensitive sensor and the heating device extending into the ceramic insulating plate from the fitting between the static conductive rod and the ceramic insulating plate, and extending out from the side wall of the ceramic insulating plate.

[0006] Preferably, the oxygen sensor is a strontium titanate oxygen sensor.

[0007] Preferably, the joint between the static conductive rod and the ceramic insulating plate is provided with corresponding extension holes and wiring holes, the extension holes are connected to the measuring cavity, the number of the extension holes is consistent with the number of connections between the oxygen sensitive sensor and the heating device, and the wiring holes extend from the joint of the ceramic insulating plate to the side wall of the ceramic insulating plate.

[0008] Preferably, an insulating collar is provided between the wiring hole and the extension hole, and the insulating collar is sleeved outside the wiring of the oxygen sensor and the heating device.

[0009] Preferably, the wire diameter of the portion of the wiring located within the insulating ring is larger than the wiring hole and the extension hole.

[0010] Preferably, the insulating ring is longer than 5 mm.

[0011] Preferably, the ceramic insulating plate includes a mounting ring, a cross buckle plate is fixedly connected inside the mounting ring, an embedding groove is provided on the cross buckle plate, the static conductive rod and the static end conductive block are embedded in the embedding groove, the wiring hole extends from the center of the cross buckle plate to the side wall of the mounting ring, a cover plate extension ring is coaxially fixedly connected to the outer wall of the static end cover plate, and the cover plate extension ring is fixedly connected to the mounting ring.

[0012] Preferably, the cover plate extension ring and the mounting ring are connected by screws.

[0013] A method for monitoring the vacuum degree of a vacuum interrupter is also disclosed, comprising the following steps:

[0014] S1. The vacuum degree monitoring assembly of the vacuum interrupter is arranged on the vacuum interrupter, the wiring of the oxygen sensor is connected to the measuring device, and the wiring of the heating device is connected to the power supply device;

[0015] S2, turning on the heating device to adjust the temperature in the measuring cavity to the working temperature of the oxygen sensor;

[0016] S3, starting the measuring device to receive monitoring data from the oxygen sensor.

[0017] Preferably, in step S3, when the oxygen concentration exceeds a set value, the measuring device issues an alarm.

[0018] Compared with the prior art, the present invention has achieved the following technical effects:

[0019] The present invention adopts an online monitoring method of the vacuum degree of the vacuum interrupter by using an oxygen sensitive sensor. Compared with the existing offline detection scheme, there is no need to disconnect the vacuum interrupter before detection, that is, the vacuum circuit breaker can be tested under power, avoiding the disturbance and loss caused by the equipment exiting and connecting to the system during offline detection. Compared with the existing online detection scheme, the oxygen sensitive sensor is extremely sensitive to oxygen. In an environment with extremely high vacuum degree, its resistance changes linearly when the vacuum degree changes. Therefore, its resistance change can reflect the vacuum degree change inside the vacuum interrupter at high vacuum degree, thereby improving the vacuum degree detection range of the online vacuum degree detection. At the same time, the oxygen sensitive sensor has high stability and a high operating temperature, so it can withstand the high temperature process in the current vacuum interrupter manufacturing process, and will not have the problem of other types of sensors failing after being subjected to high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a rear view stereoscopic structural diagram of the vacuum interrupter and monitoring components;

[0022] Figure 2 It is a front view stereoscopic structural diagram of the vacuum interrupter and the monitoring assembly;

[0023] Figure 3 It is a schematic diagram of the three-dimensional structure of the vacuum interrupter and the monitoring component (without insulating ceramic housing);

[0024] Figure 4 A perspective schematic diagram of a monitoring assembly installed in a vacuum interrupter;

[0025] Figure 5 is a cross-sectional view of the vacuum interrupter and the monitoring assembly;

[0026] Figure 6 for Figure 5 A partial enlarged view of

[0027] Figure 7 It is a schematic diagram of the connection relationship between the wiring and the insulating ring.

[0028] Description of reference numerals:

[0029] 1. Measuring cavity; 2. Connecting hole; 3. Oxygen sensor; 4. Heating device; 5. Mounting ring; 6. Cross buckle plate; 7. Exposure opening; 8. Cover extension ring; 9. Screw hole; 10. Measuring connection; 11. Power connection; 12. Insulating collar;

[0030] 100, static conductive rod; 200, dynamic conductive rod; 300, static end cover plate; 400, dynamic end cover plate; 500, insulating ceramic shell; 600, static contact; 700, dynamic contact; 800, static end conductive block; 900, dynamic end conductive block; 1000, main shielding cover. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] The present embodiment provides a vacuum degree monitoring assembly for a vacuum interrupter, which is used to be installed on the vacuum interrupter to realize online monitoring of the vacuum degree of the vacuum interrupter, especially for medium and high voltage vacuum interrupters.

[0034] Vacuum interrupter, such as Figures 1 to 7As shown, it includes a static conductive rod 100, a dynamic conductive rod 200, a static end cover plate 300, a dynamic end cover plate 400, an insulating ceramic shell 500, a static contact 600, a dynamic contact 700, a static end conductive block 800, a dynamic end conductive block 900, a main shielding cover 1000, a voltage-equalizing shielding cover and a corrugated tube. The static conductive rod 100 and the dynamic conductive rod 200 are located in the insulating ceramic shell 500, the static end cover plate 300 is fixedly sealed at one end of the insulating ceramic shell 500, and the dynamic end cover plate 400 is fixedly sealed at the other end of the insulating ceramic shell 500. One end of the static conductive rod 100 is embedded in the embedding hole of the static end cover plate 300, the static end conductive block 800 is fixedly connected to the static end cover plate 300, and is sleeved on the static conductive rod 100, and the other end of the static conductive rod 100 is fixedly connected to the static contact 600. One end of the moving end cover plate 400 is slidably connected to the embedding hole of the moving end cover plate 400, the moving end conductive block 900 is fixedly connected to the moving end cover plate 400 and sleeved on the moving end cover plate 400, and one end of the moving end cover plate 400 located in the insulating ceramic housing 500 is fixedly connected to the moving contact 700. The main shielding cover 1000 is located in the insulating ceramic housing 500, and the static contact 600 and the moving contact 700 are located in the main shielding cover 1000. When the vacuum load switch and the vacuum contactor are closed, the operating mechanism closes the static contact 600 and the moving contact 700 through the movement of the moving conductive rod 200, completing the connection of the circuit.

[0035] Vacuum interrupter vacuum monitoring components, such as Figures 1 to 7As shown, it includes a measuring cavity 1 arranged in a static conductive rod 100, and the measuring cavity 1 is connected to the internal cavity of the insulating ceramic shell 500 through a connecting hole 2, so that the air environment of the measuring cavity 1 and the internal air environment of the insulating ceramic shell 500 are the same, and then monitoring the vacuum degree of the measuring cavity 1 is equivalent to monitoring the vacuum degree of the vacuum interrupter. The number of connecting holes 2 is set as needed, such as setting five connecting holes 2. An oxygen sensor 3 and a heating device 4 are installed in the measuring cavity 1. The oxygen sensor 3 is used to monitor the oxygen content of the air in the measuring cavity 1, and the heating device 4 provides a suitable working temperature for the oxygen sensor 3. A ceramic insulating plate is installed on the static end cover plate 300, and the ceramic insulating plate and the static conductive rod 100 extend out of one end of the static end cover plate 300. A revealing port 7 is provided on the ceramic insulating plate, and the revealing port 7 is used to expose the static conductive rod 100 and the static end conductive block 800, so that the static conductive rod 100 and the static end conductive block 800 are exposed to the external air environment, so that the vacuum interrupter can be electrically connected and can work normally. Two measuring wires 10 are led out from the two poles of the oxygen sensor 3, and two power supply wires 11 are led out from the heating device 4. The measuring wires 10 and the power supply wires 11 are extended into the ceramic insulating plate from the static conductive rod 100, and extend out from the side wall of the ceramic insulating plate. The measuring wires 10 and the power supply wires 11 are routed inside the static conductive rod 100 and are protected by the insulating ceramic housing 500, while the part extending out of the static conductive rod 100 is routed inside the ceramic insulating plate and is protected by the ceramic insulating plate, thereby avoiding measurement errors.

[0036] The oxygen sensor 3 transmits the monitoring results to the measuring device in real time through the measuring connection 10, so as to obtain the vacuum degree in the vacuum interrupter. The higher the oxygen content, the lower the vacuum degree. On the contrary, the lower the oxygen content, the higher the vacuum degree. The vacuum degree value is obtained according to the oxygen content value. The oxygen sensor 3 is extremely sensitive to oxygen. In an environment with extremely high vacuum, when the vacuum degree changes, that is, when the oxygen content changes, the resistance of the oxygen sensor 3 changes linearly. Then, the change in resistance can reflect the change in oxygen content, and then reflect the change in vacuum degree. Usually, the oxygen partial pressure is 10 -15 Pa to 10 -1 When Pa decreases monotonically, the resistivity of the oxygen sensor 3 increases monotonically and the conductivity decreases monotonically.

[0037] In this embodiment, Figures 1 to 7 As shown, the oxygen sensor 3 is a strontium titanate (SrTiO3) oxygen sensor. The operating temperature of the strontium titanate oxygen sensor is generally 700°C to 1000°C.

[0038] In this embodiment, Figures 1 to 7As shown, one end of the static conductive rod 100 extends out of the static end cover plate 300, and a plurality of extension holes are provided at the joint with the ceramic insulating plate. The extension holes are connected to the measuring cavity 1, and the number of the plurality of extension holes is consistent with the number of wirings of the oxygen sensor 3 and the heating device 4, that is, there are four extension holes in total, two of which are for two measuring wirings 10 to extend out, and the other two are for two power wirings 11 to extend out. A plurality of wiring holes are provided at the joint of the ceramic insulating plate and the static conductive rod 100, and the plurality of wiring holes correspond to the plurality of extension holes one by one. The wiring holes extend from the joint of the ceramic insulating plate to the side wall of the ceramic insulating plate, so that the two measuring wirings 10 and the two power wirings 11 extending out of the extension holes extend into the four wiring holes respectively and extend out from the side wall of the ceramic insulating plate.

[0039] In this embodiment, Figures 1 to 7 As shown, an insulating collar 12 is provided between each wiring hole and the corresponding extension hole, and the insulating collar 12 is sleeved on the measurement wiring 10 and the power wiring 11 .

[0040] Further, in this embodiment, if Figures 1 to 7 As shown, the wire diameter of the portion of the wiring located in the insulating collar 12 is larger than the wiring hole and the extension hole. The wire diameter of the remaining portion is the same as the wire diameter of the wiring hole and the extension hole. That is, the wire diameter of the portion of the measurement wiring 10 and the power wiring 11 located in the insulating collar 12 is larger than the wiring hole and the extension hole. This can reduce the impact of the sealing problem caused by the inability to perfectly match the wiring wire diameter with the wiring hole diameter due to processing tolerance.

[0041] Further, in this embodiment, if Figures 1 to 7 As shown, the length of the insulating collar 12 is more than 5 mm. That is, the wire diameters of the measuring wire 10 and the power wire 11 in the extension hole match the extension hole, and the wire diameter in the insulating collar 12 is larger than the extension hole, and the wire diameter is reduced to the original wire diameter again after extending 5 mm. At this time, the four wires enter the four wiring holes.

[0042] In this embodiment, Figures 1 to 7 As shown, the ceramic insulating plate includes a mounting ring 5, in which a cross buckle plate 6 is fixedly connected, and an embedding groove 13 is provided on the cross buckle plate 6 for the static conductive rod 100 and the static end conductive block 800 to be embedded, so as to achieve the fit between the cross buckle plate 6 and the static conductive rod 100. Four exposure openings 7 are formed between the cross buckle plate 6 and the mounting ring 5 to expose the static conductive rod 100 and the static end conductive block 800, so that the vacuum arc chamber can be electrically connected and work normally. The wiring hole extends from the center of the cross buckle plate 6 to the side wall of the mounting ring 5. A cover extension ring 8 is coaxially fixedly connected to the outer wall of the static end cover plate 300, and the cover extension ring 8 is fixedly connected to the mounting ring 5.

[0043] Further, in this embodiment, if Figures 1 to 7As shown, the cover plate extension ring 8 and the mounting ring 5 are connected by screws. Specifically, the mounting ring 5 and the cover plate extension ring 8 are respectively provided with screw holes 9 for screwing in. Preferably, the screw holes 9 on the mounting ring 5 and the cover plate extension ring 8 are arranged circumferentially, such as Figure 1 As shown, each of the mounting ring 5 and the cover extension ring 8 is provided with a screw hole 9. Of course, the above is only a specific number of settings, which does not mean that the screw holes 9 must be eleven, and other numbers are also possible.

[0044] Example 2

[0045] This embodiment provides a method for monitoring the vacuum degree of a vacuum interrupter. Figures 1 to 7 As shown, the following steps are included:

[0046] S1. The vacuum degree monitoring assembly of the vacuum interrupter in Example 1 is arranged on the vacuum interrupter, the measurement connection 10 of the oxygen sensor 3 is connected to the measurement device, and the power connection 11 of the heating device 4 is connected to the power supply device;

[0047] S2, turn on the heating device 4 to adjust the temperature in the measuring cavity 1 to the working temperature of the oxygen sensor 3;

[0048] S3, start the measuring device, receive the monitoring data of the oxygen sensor 3, obtain the oxygen content in the vacuum interrupter, and then obtain the vacuum degree value, and then take timely action.

[0049] In this embodiment, Figures 1 to 7 As shown, in step S3, when the oxygen concentration exceeds the set value, that is, the vacuum degree is lower than the operating standard of the vacuum interrupter, the measuring device will alarm and remind people to take action.

[0050] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A vacuum degree monitoring component for a vacuum interrupter, characterized in that: It includes a measuring cavity arranged in the static conductive rod of the vacuum arc extinguishing chamber, the measuring cavity is connected with the internal cavity of the insulating ceramic shell of the vacuum arc extinguishing chamber through a connecting hole, an oxygen sensitive sensor and a heating device are installed in the measuring cavity, a ceramic insulating plate is installed on the static end cover of the vacuum arc extinguishing chamber, the ceramic insulating plate and the static conductive rod extend out of one end of the static end cover at the joint, the ceramic insulating plate is provided with an exposure port for exposing the static conductive rod and the static end conductive block, the wiring of the oxygen sensitive sensor and the heating device extends into the ceramic insulating plate from the joint between the static conductive rod and the ceramic insulating plate, and extends out from the side wall of the ceramic insulating plate.

2. A vacuum interrupter vacuum degree monitoring assembly according to claim 1, characterized in that: The oxygen sensitive sensor adopts a strontium titanate oxygen sensitive sensor.

3. A vacuum interrupter vacuum degree monitoring assembly according to claim 1, characterized in that: The joint between the static conductive rod and the ceramic insulating plate is provided with corresponding extension holes and wiring holes, the extension holes are connected to the measuring cavity, the number of the extension holes is consistent with the number of connections between the oxygen sensitive sensor and the heating device, and the wiring holes extend from the joint between the ceramic insulating plate to the side wall of the ceramic insulating plate.

4. A vacuum interrupter vacuum degree monitoring assembly according to claim 3, characterized in that: An insulating collar is provided between the wiring hole and the extension hole, and the insulating collar is sleeved outside the wiring of the oxygen sensor and the heating device.

5. A vacuum interrupter vacuum degree monitoring assembly according to claim 3, characterized in that: The wire diameter of the portion of the wiring located in the insulating ring is larger than the wiring hole and the extension hole.

6. A vacuum interrupter vacuum degree monitoring assembly according to claim 5, characterized in that: The length of the insulating ring is more than 5 mm.

7. A vacuum interrupter vacuum degree monitoring assembly according to claim 3, characterized in that: The ceramic insulating plate includes a mounting ring, a cross buckle plate is fixedly connected inside the mounting ring, an embedding groove is provided on the cross buckle plate, the static conductive rod and the static end conductive block are embedded in the embedding groove, the wiring hole extends from the center of the cross buckle plate to the side wall of the mounting ring, a cover plate extension ring is coaxially fixedly connected to the outer wall of the static end cover plate, and the cover plate extension ring is fixedly connected to the mounting ring.

8. A vacuum interrupter vacuum degree monitoring assembly according to claim 7, characterized in that: The cover plate extension ring and the mounting ring are connected by screws.

9. A method for monitoring the vacuum degree of a vacuum interrupter, characterized in that: The following steps are involved: S1. The vacuum degree monitoring assembly of the vacuum interrupter according to any one of claims 6 to 8 is arranged on the vacuum interrupter, the wiring of the oxygen sensor is connected to the measuring device, and the wiring of the heating device is connected to the power supply device; S2, turning on the heating device to adjust the temperature in the measuring cavity to the working temperature of the oxygen sensor; S3, starting the measuring device to receive monitoring data from the oxygen sensor.

10. A vacuum degree monitoring method for a vacuum interrupter according to claim 9, characterized in that: In step S3, when the oxygen concentration exceeds a set value, the measuring device issues an alarm.

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