Oil-immersed current transformer internal short circuit arcing pressure characteristic simulation test device and test method

Abstract

The invention discloses an oil-immersed current transformer internal short circuit arcing pressure characteristic simulation test device and test method, the test device comprises a current transformer simulation device and a power supply module, the current transformer simulation device comprises: a housing configured to be filled with insulating oil; one ends of the two fixed electrodes are respectively fixed at different heights on the side wall of the shell and extend out of the side wall, and the other ends of the two fixed electrodes horizontally extend to the middle part of the shell; one end of each test electrode is fixedly connected with the inner end of the corresponding fixed electrode, and the other end of each test electrode extends up and down to get close to each other; the ends of the two test electrodes are spaced by a preset gap distance; and the outer ends of the first fixed electrode and the second fixed electrode extending out of the side wall of the shell are respectively connected with the positive electrode and the negative electrode of the power module. The test device simulates the internal short-circuit arcing working condition of the oil-immersed current transformer, collects the pressure impact on the shell of the current transformer, and provides a reference for the subsequent evaluation of the internal pressure rise and the explosion-proof performance of the oil-immersed current transformer.

Description

Technical Field

[0001] The invention relates to the field of current sensors, and in particular to a simulation test device and a test method for internal short-circuit arcing pressure characteristics of an oil-immersed current transformer. Background Art

[0002] Internal short-circuit arcing faults in oil-immersed current transformers are a major safety hazard that affects the safe and stable operation of power systems. When they occur, they will produce huge thermal-mechanical effects, causing equipment damage and even explosions, seriously threatening the safety of surrounding personnel and buildings.

[0003] During the arcing process, the high-temperature electric arc will quickly vaporize and decompose the insulating oil around it, producing a large amount of hydrocarbon mixed gas in a short period of time; and the expansion inertia of the surrounding insulating oil causes a huge pressure difference at the gas-liquid interface, which propagates outward in the form of a pressure wave, causing the pressure level inside the shell to rise suddenly, and in severe cases, it may cause an explosion.

[0004] Therefore, it is necessary to evaluate the explosion-proof performance of oil-immersed current transformers to improve their internal arc fault protection capabilities. However, the internal arc fault test of oil-immersed current transformers is a destructive test, and explosions, fires, oil leaks, flying debris and other phenomena may occur during the test. In addition, current transformers are expensive. If actual current transformers are used for testing, there are shortcomings such as high cost, long cycle and poor repeatability.

[0005] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present application. It does not necessarily belong to the prior art of the present application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above content has been disclosed before the filing date of the present application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0006] The purpose of the present invention is to provide a test device for simulating the pressure impact on the shell of an oil-immersed current transformer under the condition of short-circuit arcing inside the oil-immersed current transformer.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A simulation test device for internal short-circuit arcing pressure characteristics of an oil-immersed current transformer, comprising a current transformer simulation device and a power module, wherein the current transformer simulation device comprises:

[0009] a housing configured to be filled with insulating oil;

[0010] A first fixed electrode and a second fixed electrode, one end of each of which is respectively fixed at different heights on the side wall of the shell and protrudes out of the side wall, and the other end of each of which extends horizontally to the middle of the shell;

[0011] One end of the first test electrode is fixedly connected to the inner end of the first fixed electrode, and the other end of the first test electrode extends downward;

[0012] One end of the second test electrode is fixedly connected to the inner end of the second fixed electrode, and the other end of the second test electrode extends upward;

[0013] A preset gap distance is provided between the lower end of the first test electrode and the upper end of the second test electrode;

[0014] The outer ends of the first fixed electrode and the second fixed electrode protruding out of the side wall of the shell are respectively connected to the positive electrode and the negative electrode of the power module.

[0015] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, a metal expander is provided at the upper end of the housing of the current transformer simulation device;

[0016] The metal expander is provided with a plurality of pressure relief holes, and / or a pressure relief cover is provided above the metal expander.

[0017] Further, based on any one of the technical solutions or a combination of multiple technical solutions mentioned above, a plurality of pressure sensors are distributed on the housing of the current transformer simulation device, and are configured to detect the pressure value of the installation position thereof during the arcing stage.

[0018] Further, based on any one of the technical solutions or a combination of multiple technical solutions mentioned above, an oil filling port and an oil outlet are provided on the shell of the current transformer simulation device, wherein the setting height of the oil filling port is higher than the setting height of the first fixed electrode.

[0019] Further, according to any one of the above technical solutions or a combination of multiple technical solutions, the first fixed electrode and the second fixed electrode are arranged vertically opposite to each other;

[0020] And / or, the first test electrode and the second test electrode are vertically arranged opposite to each other;

[0021] And / or, the first test electrode is perpendicular to the first fixed electrode;

[0022] And / or, the second testing electrode is perpendicular to the second fixed electrode.

[0023] Further, based on any one of the technical solutions or a combination of multiple technical solutions mentioned above, a visual observation window is provided on the side wall of the shell of the current transformer simulation device, and the visual field of the visual observation window is configured to cover the gap between the first test electrode and the second test electrode.

[0024] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device provided by the present invention also includes a shielding cover for covering the shell of the current transformer simulation device, and the shielding cover is a transparent or translucent structure;

[0025] And / or, the housing of the current transformer simulation device is made of metal material;

[0026] And / or, the first fixed electrode and the second fixed electrode are copper-tungsten alloy electrodes;

[0027] And / or, the first test electrode and the second test electrode are copper-tungsten alloy electrodes.

[0028] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the power supply module includes a high-voltage probe, a Rogowski coil and an LC branch formed by a capacitor and an inductor connected in series, and the high-voltage probe is configured to measure the arc voltage of the arc burning process;

[0029] The LC branch passes through the Rogowski coil and is connected in parallel with the high-voltage probe, one end of the parallel connection is configured to be connected to the first fixed electrode, and the other end of the parallel connection is configured to be connected to the second fixed electrode.

[0030] According to another aspect of the present invention, the present invention provides a method for simulating the internal short-circuit arcing pressure characteristics of an oil-immersed current transformer, comprising the following steps:

[0031] The shell of the oil-immersed current transformer to be tested is used to manufacture the oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device as described above;

[0032] Connecting the first fixed electrode, the second fixed electrode and the power module of the pressure characteristic simulation test device to break down the first test electrode and the second test electrode of the pressure characteristic simulation test device with high voltage;

[0033] Pressure sensors at different positions are used to obtain pressure values ​​at various positions during the arcing stage.

[0034] Further, based on any one of the above-mentioned technical solutions or a combination of multiple technical solutions, the pressure characteristic simulation test method provided by the present invention also includes:

[0035] Using the power module to change different short-circuit currents to simulate different working conditions;

[0036] The pressure values ​​at various positions on the pressure characteristic simulation test device during the arcing stage under different short-circuit currents are recorded.

[0037] The beneficial effects brought by the technical solution provided by the present invention are as follows:

[0038] a. Design a test device to simulate the short-circuit arcing condition inside the oil-immersed current transformer, collect the pressure shock on the current transformer shell, and provide a reference for the subsequent evaluation of the internal pressure rise and explosion-proof performance of the oil-immersed current transformer;

[0039] b. After multiple arc tests, pressure data is obtained to find weak places where the pressure is higher when an internal arc fault occurs in the oil-immersed current transformer. Pressure relief devices, explosion-proof valves or explosion-proof discs are installed in these places to ensure the safety of the equipment and improve the explosion-proof performance;

[0040] c. Taking into account the capacity of the test power supply group and the test economy, a small-sized oil-immersed current transformer internal short-circuit arc pressure characteristic simulation test device is designed. The test device can not only successfully complete the test task, but also reduce the test cost;

[0041] d. The present invention quantitatively analyzes the internal short-circuit arc pressure characteristics of the oil-immersed current transformer by changing the short-circuit current during the test, thereby making up for the shortcomings of the existing oil-immersed current transformer internal short-circuit arc pressure characteristic test;

[0042] e. Setting up pressure relief structure and shielding cover can ensure the safety of the test process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 A front view of a simulation test device for internal short-circuit arcing pressure characteristics of an oil-immersed current transformer provided by an exemplary embodiment of the present invention;

[0045] Figure 2 for Figure 1 The cross-sectional view of the pressure characteristic simulation test device in the AA direction;

[0046] Figure 3A three-dimensional diagram of a simulation test device for internal short-circuit arcing pressure characteristics of an oil-immersed current transformer provided as an exemplary embodiment of the present invention;

[0047] Figure 4 A schematic diagram of a circuit structure of a current transformer simulation device connected to a power module provided by an exemplary embodiment of the present invention;

[0048] Figure 5 A schematic flow chart of a method for simulating a test of internal short-circuit arcing pressure characteristics of an oil-immersed current transformer provided as an exemplary embodiment of the present invention.

[0049] Among them, the figure marks include: 100-current transformer simulation device, 110-shell, 122-first fixed electrode, 124-second fixed electrode, 126-first test electrode, 128-second test electrode, 132-metal expander, 134-pressure relief hole, 136-pressure relief cover, 140-pressure sensor, 152-oil filling port, 154-oil outlet, 160-visual observation window, 200-power module, 210-capacitor, 220-inductor, 230-Rogowski coil, 240-high voltage probe, 300-shielding cover. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0052] The present invention aims to propose a method for simulating the internal short-circuit arcing condition of an oil-immersed current transformer to test the pressure shock on the shell of the current transformer, so as to provide a reference for the subsequent evaluation of the internal pressure rise and explosion-proof performance of the oil-immersed current transformer.

[0053] In one embodiment of the present invention, a simulation test device for the internal short-circuit arcing pressure characteristics of an oil-immersed current transformer is provided. Figures 1 to 3 As shown, the test device includes a current transformer simulation device 100 and a power module 200, wherein the current transformer simulation device 100 includes:

[0054] A housing 110, wherein the housing 110 is provided with an oil filling port 152 and an oil outlet 154 for filling with insulating oil. The housing 110 is a housing of an oil-immersed current transformer to be simulated and is made of a high-strength metal material. One of the purposes of the test is to evaluate the explosion-proof performance of the housing of the oil-immersed current transformer;

[0055] The first fixed electrode 122 and the second fixed electrode 124 have one end fixed at different heights on the side wall of the housing 110 and protrude from the side wall, and the other end of the two ends extend horizontally to the middle of the housing 110; the setting height of the oil filling port 152 determines the height of the oil filling, so it is higher than the setting height of the first fixed electrode 122 and the second fixed electrode 124;

[0056] One end of the first test electrode 126 is fixedly connected to the inner end of the first fixed electrode 122, and the other end of the first test electrode 126 extends downward;

[0057] One end of the second test electrode 128 is fixedly connected to the inner end of the second fixed electrode 124, and the other end of the second test electrode 128 extends upward;

[0058] A preset gap distance is provided between the lower end of the first test electrode 126 and the upper end of the second test electrode 128;

[0059] The outer ends of the first fixed electrode 122 and the second fixed electrode 124 extending out of the side wall of the shell 110 are respectively connected to the positive and negative electrodes of the power module 200. The first fixed electrode 122, the second fixed electrode 124, the first test electrode 126, and the second test electrode 128 can be copper-tungsten alloy electrodes.

[0060] In one embodiment of the present invention, the outer ends of the two fixed electrodes are welded to the inner wall of the shell 110 and protrude to the outside of the shell 110 to facilitate connection with the electrodes of the external power module 200; the function of the two fixed electrodes is to fix the test electrodes at their inner ends. For example, a threaded hole is provided at the inner end. The first test electrode 126 is fixed to the inner end of the first fixed electrode 122 by screws / bolts, and the second test electrode 128 is fixed to the inner end of the second fixed electrode 124 by screws / bolts. The test electrodes can be replaced after each test is completed. Accordingly, the top end of the shell 110 is an openable or detachable opening structure to facilitate replacement of the test electrodes.

[0061] Continue to see Figure 1 A metal expander 132 is provided at the upper end of the housing 110 of the current transformer simulation device 100. When the volume of the transformer oil (insulating oil) inside the current transformer changes due to temperature changes, the volume of the metal expander changes accordingly to play a role in volume compensation;

[0062] The metal expander 132 is provided with a plurality of pressure relief holes 134 , and / or a pressure relief cover 136 is provided above the metal expander 132 , so as to achieve pressure balance inside and outside the transformer housing.

[0063] Furthermore, a plurality of pressure sensors 140 are distributed on the housing 110 of the current transformer simulation device 100, and are configured to detect the pressure value of the installation position thereof during the arcing stage, such as Figure 1 and Figure 3 As shown, pressure sensors 140 are provided at three different heights, namely, the upper, middle and lower positions of the side wall of the housing 110 .

[0064] In a specific embodiment, the first fixed electrode 122 and the second fixed electrode 124 are arranged horizontally and face each other vertically, the first test electrode 126 is perpendicular to the first fixed electrode 122, the second test electrode 128 is perpendicular to the second fixed electrode 124, and the first test electrode 126 and the second test electrode 128 are arranged vertically and face each other vertically. The connection structure of the first fixed electrode 122 and the first test electrode 126 and the connection structure of the second fixed electrode 124 and the second test electrode 128 are arranged vertically symmetrically in the housing 110, and further, it is preferred to select fixed electrodes of appropriate length so that they extend horizontally inward to the central vertical axis of the housing 110, that is, the gap between the first test electrode 126 and the second test electrode 128 is located on the central vertical axis of the housing or adjacent to the central vertical axis.

[0065] In one embodiment, a visual observation window 160 is provided on the side wall of the housing 110 of the current transformer simulation device 100 , and is configured to cover the gap between the first test electrode 126 and the second test electrode 128 so that the internal arcing condition can be observed at any time.

[0066] The oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device provided in an embodiment of the present invention also includes a shielding cover 300 for covering the shell 110 of the current transformer simulation device 100. The shielding cover is a transparent or translucent structure and can be made of high-strength rate material. The internal arcing situation can be observed through the shielding cover 300 and the visual observation window 160, and the shielding cover 300 can ensure the personal safety of the test personnel.

[0067] The power module 200 is configured to provide high voltage electricity to the first fixed electrode 122 and the second fixed electrode 124. Figure 4 As shown, the power module 200 includes a high-voltage probe 240, a Rogowski coil 230, and an LC branch formed by a capacitor 210 and an inductor 220 connected in series. The high-voltage probe 240 is configured to measure the arc voltage of the arc burning process;

[0068] The LC branch passes through the Rogowski coil 230 and is connected in parallel with the high-voltage probe 240. One end of the parallel connection is configured to be connected to the first fixed electrode 122, and the other end of the parallel connection is configured to be connected to the second fixed electrode 124. The Rogowski coil 230 is used to measure the loop current of the power module 200.

[0069] In one embodiment of the present invention, a method for simulating the internal short-circuit arcing pressure characteristics of an oil-immersed current transformer is provided. Figure 5 As shown, the pressure characteristics simulation test method includes the following steps:

[0070] The shell of the oil-immersed current transformer to be tested is used to manufacture the oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device as described above;

[0071] Connecting the first fixed electrode, the second fixed electrode and the power module of the pressure characteristic simulation test device to break down the first test electrode and the second test electrode of the pressure characteristic simulation test device with high voltage;

[0072] Pressure sensors at different positions are used to obtain pressure values ​​at various positions during the arcing stage.

[0073] Furthermore, the pressure characteristic simulation test method provided by the embodiment of the present invention also includes:

[0074] Use the power module to change different short-circuit currents to simulate different working conditions;

[0075] The pressure values ​​at various positions on the pressure characteristic simulation test device during the arcing stage under different short-circuit currents are recorded.

[0076] By obtaining pressure data after multiple arc tests, we can find the weak places where the pressure is higher when an internal arc fault occurs in the oil-immersed current transformer. Pressure relief devices, explosion-proof valves or explosion-proof plates can be installed in these places to ensure the safety of the equipment and improve the explosion-proof performance.

[0077] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0078] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A simulation test device for internal short-circuit arcing pressure characteristics of an oil-immersed current transformer, characterized in that: The invention comprises a current transformer simulation device (100) and a power supply module (200), wherein the current transformer simulation device (100) comprises: a housing (110) configured to be filled with insulating oil; A first fixed electrode (122) and a second fixed electrode (124), one end of each of which is respectively fixed at different heights on the side wall of the housing (110) and protrudes out of the side wall, and the other end of each of which extends horizontally to the middle of the housing (110); One end of the first test electrode (126) is fixedly connected to the inner end of the first fixed electrode (122), and the other end of the first test electrode (126) extends downward; One end of the second test electrode (128) is fixedly connected to the inner end of the second fixed electrode (124), and the other end of the second test electrode (128) extends upward; A preset gap distance is provided between the lower end of the first test electrode (126) and the upper end of the second test electrode (128); The outer ends of the first fixed electrode (122) and the second fixed electrode (124) protruding out of the side wall of the housing (110) are respectively connected to the positive electrode and the negative electrode of the power module (200).

2. The oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device according to claim 1, characterized in that: A metal expander (132) is provided at the upper end of the housing (110) of the current transformer simulation device (100); The metal expander (132) is provided with a plurality of pressure relief holes (134), and / or a pressure relief cover (136) is provided above the metal expander (132).

3. The internal short-circuit arcing pressure characteristic simulation test device of an oil-immersed current transformer according to claim 1, characterized in that: A plurality of pressure sensors (140) are distributed on the housing (110) of the current transformer simulation device (100), and are configured to detect the pressure value of the position where the pressure sensors are installed during the arcing stage.

4. The oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device according to claim 1, characterized in that: An oil filling port (152) and an oil outlet (154) are provided on the housing (110) of the current transformer simulation device (100), wherein the setting height of the oil filling port (152) is higher than the setting height of the first fixed electrode (122).

5. The internal short-circuit arcing pressure characteristic simulation test device of oil-immersed current transformer according to claim 1, characterized in that: The first fixed electrode (122) and the second fixed electrode (124) are arranged opposite to each other up and down; And / or, the first test electrode (126) and the second test electrode (128) are arranged vertically opposite to each other; and / or, the first test electrode (126) is perpendicular to the first fixed electrode (122); And / or, the second testing electrode (128) is perpendicular to the second fixed electrode (124).

6. The oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device according to claim 1, characterized in that: A visual observation window (160) is provided on the side wall of the housing (110) of the current transformer simulation device (100), and is configured such that a visual field covers the gap between the first test electrode (126) and the second test electrode (128).

7. The internal short-circuit arcing pressure characteristic simulation test device of an oil-immersed current transformer according to claim 1, characterized in that: It also includes a shielding cover (300) for covering the housing (110) of the current transformer simulation device (100), wherein the shielding cover is a transparent or semi-transparent structure; And / or, the housing (110) of the current transformer simulation device (100) is made of metal material; And / or, the first fixed electrode (122) and the second fixed electrode (124) are copper-tungsten alloy electrodes; And / or, the first test electrode (126) and the second test electrode (128) are copper-tungsten alloy electrodes.

8. The internal short-circuit arcing pressure characteristic simulation test device of an oil-immersed current transformer according to any one of claims 1 to 7, characterized in that: The power supply module (200) comprises a high-voltage probe (240), a Rogowski coil (230), and an LC branch formed by a capacitor (210) and an inductor (220) connected in series, wherein the high-voltage probe (240) is configured to measure an arc voltage during an arc burning process; The LC branch passes through the Rogowski coil (230) and is connected in parallel with the high-voltage probe (240), one end of the parallel connection is configured to be connected to the first fixed electrode (122), and the other end of the parallel connection is configured to be connected to the second fixed electrode (124).

9. A method for simulating the internal short-circuit arcing pressure characteristics of an oil-immersed current transformer, characterized in that: The following steps are involved: The oil-immersed current transformer internal short-circuit arcing pressure characteristic simulation test device as claimed in claim 3 is manufactured by using the shell of the oil-immersed current transformer to be tested; Connecting the first fixed electrode, the second fixed electrode and the power module of the pressure characteristic simulation test device to break down the first test electrode and the second test electrode of the pressure characteristic simulation test device with high voltage; Pressure sensors at different positions are used to obtain pressure values ​​at various positions during the arcing stage.

10. The pressure characteristic simulation test method according to claim 9, characterized in that: Also includes: Using the power module to change different short-circuit currents to simulate different working conditions; The pressure values ​​at various positions on the pressure characteristic simulation test device during the arcing stage under different short-circuit currents are recorded.

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