Vacuum interrupter with composite breakdown path vacuum level detection electrode structure and application

Abstract

A composite breakdown path vacuum degree detection electrode structure and a vacuum arc-extinguishing chamber using the same, the composite breakdown path vacuum degree detection electrode structure comprising multiple groups of electrodes, each group of electrodes having different shapes and breakdown conditions; the multiple groups of electrodes are uniformly distributed on a ceramic insulator base of an end cover plate of the vacuum arc-extinguishing chamber, so that when independent voltage conditions are applied to the electrodes, the breakdown results of different electrode structures and different vacuum gaps under different breakdown paths show corresponding vacuum degree or gas pressure ranges under the same vacuum degree and gas pressure conditions; the composite breakdown path vacuum degree detection electrode structure has the function of realizing online monitoring of the vacuum degree of a high-voltage grade vacuum arc-extinguishing chamber, and avoids the defect that a single electrode detection structure cannot distinguish between high vacuum and atmospheric environment, thereby improving the accuracy of the online monitoring function of the vacuum degree.

Description

Technical Field

[0001] This invention belongs to the technical field of high-current vacuum circuit breakers, specifically relating to a vacuum interrupter chamber for detecting vacuum level of composite breakdown path electrode and its application. Background Technology

[0002] Vacuum interrupters have gained popularity in power systems due to their excellent insulation performance and environmental friendliness. To push vacuum interrupters to higher voltage levels, a series of design and manufacturing processes have been implemented for their electrodes. Vacuum switches have currently reached a voltage level of 126kV, but the application and promotion of high-voltage vacuum switches faces the technical challenge of online monitoring of the vacuum level in vacuum interrupters.

[0003] Traditional vacuum monitoring methods have many shortcomings and have not yet been widely applied to the online monitoring of vacuum interrupters. Firstly, traditional vacuum monitoring devices are mostly too bulky and redundant, making them difficult to use in the field. Secondly, traditional vacuum detection technology cannot monitor the vacuum status online while the circuit is energized, and cannot reflect the current vacuum condition of the vacuum switch in real time, thus posing certain safety hazards. Thirdly, single-electrode vacuum monitoring technology cannot effectively distinguish between high vacuum, low vacuum, low gas pressure, and high gas pressure conditions, resulting in inconsistent vacuum detection accuracy. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention tackles the industry challenge of online vacuum degree detection in high-voltage vacuum interrupters by proposing a composite breakdown path vacuum degree detection electrode structure and its application in a vacuum interrupter. Considering the specific vacuum degree measurement requirements of high-voltage vacuum interrupters, and taking into account the significant differences in breakdown voltage between metal electrode gaps under high, low, low, and high gas pressure conditions, this invention integrates extensive metal gap breakdown test data to propose a composite breakdown path vacuum degree detection electrode structure design. This enables the detection of vacuum degree in high-voltage vacuum interrupters, and the composite breakdown path design improves the accuracy of vacuum degree detection.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A composite breakdown path vacuum degree detection electrode structure is located on the end cover plate of a vacuum interrupter. It includes multiple sets of electrodes of different shapes, an external voltage application device, and an external breakdown current detection device. To prevent breakdown interference, voltage is applied independently to each set of electrodes, and the external breakdown current is detected independently. Since different electrode shapes cause different distortions in the electric field strength, and with adjustments to the electrode gap, the vacuum degree range induced by breakdown under a specific voltage varies significantly depending on the electrode shape. Experiments are used to calibrate the vacuum degree range of breakdown under specific voltages and vacuum gaps for multiple sets of electrodes. Different combinations of electrode breakdown results represent different current vacuum conditions. Under the same vacuum degree and gas pressure conditions, after each electrode is independently voltaged, the combination of breakdown results for different electrode structures and gaps under different breakdown paths is observed, revealing the corresponding vacuum degree or gas pressure range.

[0007] The cathode emitting electrode of the composite breakdown path vacuum degree detection electrode structure 201 is a combination of needle electrode, ball electrode, rod electrode, plate electrode or ring electrode with differential breakdown characteristics; the anode collecting electrode of the composite breakdown path vacuum degree detection electrode structure 201 is spoon-shaped, box-shaped, spherical or ellipsoidal.

[0008] The composite breakdown path vacuum detection electrode structure 201 includes three sets of electrodes: a needle electrode 102 and a needle electrode collecting electrode 101, a ball electrode 104 and a ball electrode collecting electrode 103, and a rod electrode 106 and a rod electrode collecting electrode 105. The needle electrode collecting electrode 101 is generally spoon-shaped, with its handle parallel to the needle electrode 102, and the spoon portion wraps around the end of the needle electrode 102 to ensure electron collection. The ball electrode collecting electrode 103 is generally spoon-shaped, with its handle parallel to the ball electrode 104, and the spoon portion wraps around the end of the ball electrode 104 to ensure electron collection. The rod electrode collecting electrode 105 is generally spoon-shaped, with its handle parallel to the rod electrode 106, and the spoon portion wraps around the end of the rod electrode 106 to ensure electron collection. The three sets of electrodes are connected and welded to a ceramic insulator base 107 located on the end cover plate of the vacuum interrupter, and are evenly distributed.

[0009] The needle electrode 102 and the needle electrode collecting electrode 101 serve as the electrode cathode and electrode anode, respectively; the ball electrode 104 and the ball electrode collecting electrode 103 serve as the electrode cathode and electrode anode, respectively; and the rod electrode 106 and the rod electrode collecting electrode 105 serve as the electrode cathode and electrode anode, respectively. The external terminals of the needle electrode 102, the ball electrode 104, and the rod electrode 106 are all grounded. Independent voltages are applied to the needle electrode collecting electrode 101, the ball electrode collecting electrode 103, and the rod electrode collecting electrode 105, respectively. All three sets of electrodes are placed inside the vacuum interrupter 202, meaning that the three sets of electrodes are under the same vacuum and pressure conditions.

[0010] The needle electrode 102, ball electrode 104, and rod electrode 106 of the composite breakdown path vacuum degree detection electrode structure 201 serve as cathode emitting electrodes, while the needle electrode collecting electrode 101, ball electrode collecting electrode 103, and rod electrode collecting electrode 105 serve as anode collecting electrodes. The cathode emitting electrode and anode collecting electrode are both made of a combination of copper (Cu), copper-chromium alloy (CuCr), iron (Fe), tungsten (W), and aluminum (Al). The selected cathode emitting electrode and anode collecting electrode materials should ensure that the breakdown paths of different electrode combinations show significant differences in the left and right branches of the Paschen curve, i.e., under low pressure, high vacuum and high pressure, low vacuum environments.

[0011] The vacuum gaps of the various groups of electrodes in the composite breakdown path vacuum degree detection electrode structure 201 are inconsistent. It is necessary to use the gap corresponding to the maximum difference in the vacuum degree range caused by breakdown under a specific voltage for different electrode shapes obtained experimentally, based on the specific electrode shape and the selected material, in order to improve the vacuum degree detection accuracy.

[0012] The composite breakdown path vacuum degree detection electrode structure 201 is installed on the stationary end cover plate 111 or the moving end cover plate 121 of the vacuum interrupter.

[0013] A vacuum interrupter includes the aforementioned composite breakdown path vacuum degree detection electrode structure 201, a stationary end shield 112, a central main shield 116, a moving end shield 120, a stationary end cover 111 welded to the stationary end shield 112, a stationary end ceramic shell 113 welded to the stationary end cover 111, a moving end cover 121 welded to the moving end shield 120, and a moving end ceramic shell 119 welded to the moving end cover 121. It also includes a stationary conductive rod 114 and a stationary contact 115, and a moving end conductive rod 118 and a moving contact 117.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1) This invention adds a composite breakdown path vacuum degree detection electrode structure that meets structural requirements to the vacuum interrupter chamber while almost destroying the internal structural design of the vacuum interrupter chamber, thus ensuring the original insulation and breaking performance of the vacuum interrupter chamber itself, and enabling online monitoring of the vacuum degree of the energized vacuum interrupter chamber.

[0016] 2) This invention addresses the significant differences in breakdown voltage between metal electrode gaps under high vacuum, low vacuum, low gas pressure, and high gas pressure conditions. By integrating a large amount of metal gap breakdown test data, it proposes a composite breakdown path vacuum level detection electrode structure design, which can achieve multi-path metal gap breakdown and enable the detection of vacuum level in high-voltage vacuum interrupters.

[0017] 3) This invention proposes a differentiated structural design for each electrode in the composite breakdown path. By differentiating the electrode structures of different paths, the breakdown paths of different electrode combinations have significant differences in the left and right branches of the Paschen curve, i.e., low pressure, high vacuum and high pressure, low vacuum environments. This avoids the defect of single-electrode detection structures that cannot distinguish between high vacuum and atmospheric environments, and improves the accuracy of vacuum degree detection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the installation position of the vacuum degree detection electrode structure for composite breakdown paths.

[0019] Figures 2(a) and 2(b) are the front view and perspective view of the composite breakdown path vacuum degree detection electrode structure.

[0020] Figures 3(a) and 3(b) are perspective and cross-sectional views of the needle electrode assembly structure.

[0021] Figures 4(a) and 4(b) are a three-dimensional view and a cross-sectional view of the ball electrode assembly structure.

[0022] Figures 5(a) and 5(b) are perspective and cross-sectional views of the rod electrode assembly structure.

[0023] Figure 6 It is a diagram showing the vacuum range of breakdown of multiple sets of electrodes under specific voltage and vacuum gap conditions, as determined by experiments.

[0024] Figure 7 This is a cross-sectional view of a vacuum interrupter with a composite breakdown path vacuum degree detection electrode structure. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 1As shown, the composite breakdown path vacuum degree detection electrode structure 201 is located on the stationary end cover plate 111 or the moving end cover plate 121 of the vacuum interrupter. The emitting electrode and the collecting electrode are alternately distributed, with two electrodes forming a group, and are evenly distributed on the ceramic insulating base 107 of the stationary end cover plate 111 or the moving end cover plate 121.

[0027] As shown in Figures 2(a) and 2(b), the composite breakdown path vacuum detection electrode structure 201 includes a needle electrode 102 and a needle electrode collecting electrode 101, a ball electrode 104 and a ball electrode collecting electrode 103, a rod electrode 106 and a rod electrode collecting electrode 105. The needle electrode collecting electrode 101 is generally spoon-shaped, with its handle parallel to the needle electrode 102. The spoon portion wraps around the end of the needle electrode 102, ensuring the electron collection effect. The ball electrode collecting electrode 103 is generally spoon-shaped, with its handle parallel to the ball electrode 104. The spoon portion wraps around the end of the ball electrode 104, ensuring the electron collection effect. The rod electrode collecting electrode 105 is generally spoon-shaped, with its handle parallel to the rod electrode 106. The spoon portion wraps around the end of the rod electrode 106, ensuring the electron collection effect.

[0028] As shown in Figures 3(a) and 3(b), the needle electrode assembly structure includes a needle electrode 102 and a needle electrode collecting electrode 101. The needle electrode 102 is grounded at the cathode and serves as the emitting electrode to emit electrons. The needle electrode collecting electrode 101 is connected to the positive terminal of an external power supply at the anode and serves as the collecting electrode to collect electrons. The electrode materials of the needle electrode 102 and the needle electrode collecting electrode 101 can be selected from materials such as copper (Cu), copper-chromium alloy (CuCr), iron (Fe), tungsten (W), and aluminum (Al). The electrode gap is determined when the vacuum degree range at which the needle electrode assembly structure induces breakdown under a specific voltage differs most from other electrode assembly structures, as obtained experimentally.

[0029] As shown in Figures 4(a) and 4(b), the spherical electrode assembly structure includes a spherical electrode 104 and a spherical electrode collecting electrode 103. The spherical electrode 104 is grounded at the cathode and serves as the emitting electrode to emit electrons. The spherical electrode collecting electrode 103 is connected to the positive terminal of an external power supply at the anode and serves as the collecting electrode to collect electrons. The electrode materials of the spherical electrode 104 and the spherical electrode collecting electrode 103 can be selected from materials such as copper (Cu), copper-chromium alloy (CuCr), iron (Fe), tungsten (W), and aluminum (Al). The electrode gap is determined when the vacuum degree range at which the spherical electrode assembly structure induces breakdown under a specific voltage differs most significantly from other electrode assembly structures obtained experimentally.

[0030] As shown in Figures 5(a) and 5(b), the rod electrode assembly structure includes a rod electrode 106 and a rod electrode collecting electrode 105. Rod electrode 106 is grounded at the cathode and serves as the emitting electrode to emit electrons. Rod electrode collecting electrode 105 is connected to the positive terminal of an external power supply at the anode and serves as the collecting electrode to collect electrons. The electrode materials of rod electrode 106 and rod electrode collecting electrode 105 can be selected from materials such as copper (Cu), copper-chromium alloy (CuCr), iron (Fe), tungsten (W), and aluminum (Al). The electrode gap is determined when the vacuum degree range at which the rod electrode assembly structure induces breakdown under a specific voltage differs most from other electrode assembly structures, as obtained experimentally.

[0031] like Figure 6 As shown, different electrode shapes cause different distortions in the electric field strength. Furthermore, with adjustments to the electrode gap, the vacuum range at which different electrode shapes induce breakdown under a specific voltage will vary significantly. Experiments calibrated the vacuum range at which three electrode combinations broke down under different electrode gaps. Based on the combination of breakdown results for different electrode structure metal gap distances under different breakdown paths, the current leakage condition of the vacuum interrupter and the leakage coefficient α were determined. To facilitate standardization, typical characteristic values ​​within the currently determined vacuum range were used to represent the current leakage rate and leakage coefficient. For example, if a specific voltage U is applied to the rod electrode combination, needle electrode combination, and ball electrode combination... A U B U C If none of the three electrode gaps break down, the vacuum interrupter has a normal vacuum level and a leakage coefficient α = 0. If only the needle electrode combination breaks down, the vacuum interrupter leaks 20% and the leakage coefficient α = 0.2. If the rod electrode combination and the needle electrode combination break down, but the ball electrode combination does not, the vacuum interrupter leaks 30% and the leakage coefficient α = 0.3. If all three electrode gaps break down, the vacuum interrupter leaks 60% and the leakage coefficient α = 0.6. If the rod electrode combination and the ball electrode combination break down, but the needle electrode combination does not, the vacuum interrupter leaks 80% and the leakage coefficient α = 0.8. If only the ball electrode combination breaks down, the vacuum interrupter leaks completely and the leakage coefficient α = 1.

[0032] like Figure 7As shown, a vacuum interrupter with a composite breakdown path vacuum degree detection electrode structure includes a composite breakdown path vacuum degree detection electrode structure 201 placed on the stationary end cover plate 111 or the moving end cover plate 121 of the vacuum interrupter. The main body consists of, from top to bottom, a stationary end shield 112, a central main shield 116, a moving end shield 120, a stationary end cover plate 111 welded to the stationary end shield 112, a stationary end ceramic shell 113 welded to the stationary end cover plate 111, a moving end cover plate 121 welded to the moving end shield 120, and a moving end ceramic shell 119 welded to the moving end cover plate 121. It also includes a stationary end conductive rod 114 and a stationary contact 115, and a moving end conductive rod 118 and a moving contact 117.

[0033] This invention is not limited to the preferred embodiments described above. Those skilled in the art can make modifications and variations to the composite breakdown path vacuum degree detection electrode structure and its application in a vacuum interrupter based on the teachings of this invention. All such modifications and variations should fall within the protection scope of this invention.

Claims

1. A composite breakdown path vacuum degree detection electrode structure, characterized in that: The composite breakdown path vacuum degree detection electrode structure is located on the end cover plate of the vacuum interrupter chamber; It includes multiple sets of electrodes of different shapes, an external voltage application device, and an external breakdown current detection device; To prevent breakdown interference, voltages were applied independently to each group of electrodes, and external breakdown currents were detected independently. Since different electrode shapes cause different distortions in the electric field strength, and with adjustments to the electrode gap, the vacuum range at which different electrode shapes induce breakdown under a specific voltage will vary significantly, experiments were conducted to calibrate the vacuum range at which multiple groups of electrodes broke down under specific voltages and vacuum gaps. Different combinations of electrode breakdown results represent different current vacuum conditions. Under the same vacuum and gas pressure conditions, after voltages were applied independently to each electrode, combinations of breakdown results for different electrode structures and gaps under different breakdown paths were observed, revealing the corresponding vacuum or gas pressure range. The composite breakdown path vacuum degree detection electrode structure (201) includes three sets of electrodes; The three sets of electrodes are a needle electrode (102) and a needle electrode collecting electrode (101), a ball electrode (104) and a ball electrode collecting electrode (103), and a rod electrode (106) and a rod electrode collecting electrode (105). The needle electrode collecting electrode (101) is spoon-shaped, with its handle parallel to the needle electrode (102). The spoon wraps around the end of the needle electrode (102) to ensure electron collection. The ball electrode collecting electrode (103) is spoon-shaped, with its handle parallel to the ball electrode (104). The spoon wraps around the end of the ball electrode (104) to ensure electron collection. The rod electrode collecting electrode (105) is spoon-shaped, with its handle parallel to the rod electrode (106). The spoon wraps around the end of the rod electrode (106) to ensure electron collection. The three sets of electrodes are connected and welded to a ceramic insulator base (107) located on the end cover plate of the vacuum interrupter, and are evenly distributed. The needle electrode (102) and the needle electrode collecting electrode (101) serve as the electrode cathode and electrode anode, respectively. The ball electrode (104) and the ball electrode collecting electrode (103) serve as the electrode cathode and electrode anode, respectively. The rod electrode (106) and the rod electrode collecting electrode (105) serve as the electrode cathode and electrode anode, respectively. The external terminals of the needle electrode (102), the ball electrode (104), and the rod electrode (106) are all grounded. Independent voltages are applied to the needle electrode collecting electrode (101), the ball electrode collecting electrode (103), and the rod electrode collecting electrode (105). All three sets of electrodes are placed inside the vacuum interrupter (202), that is, the three sets of electrodes are under the same vacuum and pressure conditions.

2. The composite breakdown path vacuum degree detection electrode structure according to claim 1, characterized in that: The cathode emitting electrode of the composite breakdown path vacuum degree detection electrode structure (201) is a combination of needle electrode, ball electrode, rod electrode, plate electrode or ring electrode with differential breakdown characteristics; the anode collecting electrode of the composite breakdown path vacuum degree detection electrode structure (201) is spoon-shaped, box-shaped, spherical or ellipsoidal.

3. The composite breakdown path vacuum degree detection electrode structure according to claim 1, characterized in that: The needle electrode (102), ball electrode (104), and rod electrode (106) of the composite breakdown path vacuum degree detection electrode structure (201) serve as cathode emitting electrodes, and the needle electrode collecting electrode (101), ball electrode collecting electrode (103), and rod electrode collecting electrode (105) serve as anode collecting electrodes. The cathode emitting electrode and anode collecting electrode are both made of a combination of copper (Cu), copper-chromium alloy (CuCr), iron (Fe), tungsten (W), and aluminum (Al). The selected cathode emitting electrode and anode collecting electrode materials should make the breakdown paths of different electrode combinations significantly different in the left and right branches of the Paschen curve, i.e., low pressure, high vacuum and high pressure, low vacuum environments.

4. The composite breakdown path vacuum degree detection electrode structure according to claim 1, characterized in that: The vacuum gaps of the various groups of electrodes in the composite breakdown path vacuum degree detection electrode structure (201) are inconsistent. It is necessary to use the gap corresponding to the maximum difference in the vacuum degree range caused by breakdown under a specific voltage based on the specific electrode shape and the selected material, obtained experimentally, to improve the vacuum degree detection accuracy.

5. The composite breakdown path vacuum degree detection electrode structure according to claim 1, characterized in that: The composite breakdown path vacuum degree detection electrode structure (201) is installed on the stationary end cover plate (111) or the moving end cover plate (121) of the vacuum interrupter.

6. A vacuum interrupter, characterized in that: The vacuum interrupter includes the composite breakdown path vacuum degree detection electrode structure (201) as described in any one of claims 1-5, a stationary end shield (112), a central main shield (116), a moving end shield (120), a stationary end cover plate (111) welded to the stationary end shield (112), a stationary end ceramic shell (113) welded to the stationary end cover plate (111), a moving end cover plate (121) welded to the moving end shield (120), a moving end ceramic shell (119) welded to the moving end cover plate (121), and also includes a stationary end conductive rod (114) and a stationary contact (115), a moving end conductive rod (118) and a moving contact (117).

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