Alternating current bushing arc test device and system for transformer

Abstract

The invention relates to an alternating-current bushing arc test device and system for a transformer, and is applied to an arc test of a high-voltage bushing. The high-voltage bushing comprises a first tube body, a capacitor core wrapping the outer side of the first tube body, a first metal piece and a second metal piece arranged at the two ends of the first tube body, a first insulating sleeve and a second insulating sleeve used for sealing the capacitor core, an end screen cover arranged on the side, away from the first metal piece, of the first insulating sleeve, and an electrode arc assembly. The electrode arc assembly comprises at least two electrodes and an arc wire used for connecting the at least two electrodes, the at least two electrodes are arranged at preset fault simulation positions on the high-voltage bushing, and the electrode arc assembly is used for generating a simulation arc after being electrified. According to the scheme provided by the invention, multiple arc fault modes can be accurately simulated, and the comprehensiveness and accuracy of the test process are improved.

Description

Technical Field

[0001] This application relates to the field of transformer bushing technology, and in particular to an AC bushing arc testing device and system for transformers. Background Technology

[0002] High-voltage AC bushings are key components of transformer equipment, undertaking important functions of electrical connection and insulation support. Bushing arcing faults can trigger a series of serious accidents, including bushing deflagration and transformer fires, leading to prolonged power system outages and causing significant economic losses and social impact.

[0003] In related technologies, bushing performance testing primarily employs the static pressure method to verify mechanical and sealing properties. However, this method cannot simulate the transient pressure changes within the bushing during arcing faults. Industry standards have not yet established technical requirements and testing methods for the explosion-proof and fire-resistant performance of bushings, leaving bushing manufacturers without clear design guidelines and verification methods. Particularly in simulating different types of arcing faults, existing technologies cannot accurately simulate various fault modes such as capacitor core surface flashover and main insulation breakdown, making it difficult to comprehensively evaluate the explosion-proof and fire-resistant performance of bushings. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, this application provides an AC bushing arc testing device and system for transformers, which can accurately simulate various arc fault modes and improve the comprehensiveness and accuracy of the testing process.

[0005] The first aspect of this application provides an arc testing device for AC bushings of transformers, applied to arc testing of high-voltage bushings. The high-voltage bushing includes a first tube body, a capacitor core covering the outside of the first tube body, a first metal part and a second metal part disposed at both ends of the first tube body, a first insulating sleeve and a second insulating sleeve for sealing the capacitor core, a final shield cover disposed on the side of the first insulating sleeve away from the first metal part, and an electrode arc assembly. The electrode arc assembly includes at least two electrodes and an arc wire for connecting the at least two electrodes. The at least two electrodes are disposed at preset fault simulation positions on the high-voltage bushing. The electrode arc assembly is used to generate a simulated arc after energization.

[0006] In conjunction with the first aspect, in one possible implementation of the first aspect, one end of the electrode is disposed outside the capacitor core and inside the first insulating sleeve, the first electrode of the electrode protrudes through the first metal piece, one end of the second electrode of the electrode protrudes through the end screen cover, and the electrode arc assembly can be used to simulate the surface arc flashover fault of the air-side capacitor core of the high-voltage bushing.

[0007] In conjunction with the first aspect, in one possible implementation of the first aspect, the first electrode of the at least two electrodes is the first tube body, the second electrode of the at least two electrodes is disposed inside the end screen cover, the capacitor core has a hollow area on one side corresponding to the second electrode, the arc wire is connected to one side of the first electrode and one side of the second electrode respectively through the hollow area, and the electrode arc assembly can be used to simulate the main insulation breakdown arc fault of the capacitor core.

[0008] In conjunction with the first aspect, in one possible implementation of the first aspect, one end of the first electrode of the at least two electrodes is disposed outside the capacitor core and inside the second insulating sleeve, the other end of the first electrode extends through the end screen cover, the second electrode of the at least two electrodes is the second metal piece, and the electrode arc assembly can be used to simulate the surface arc flashover fault of the capacitor core in the high-voltage bushing.

[0009] In conjunction with the first aspect, in one possible implementation of the first aspect, the high-voltage bushing further includes a flange located on the side of the end cover away from the first insulating sleeve.

[0010] In conjunction with the first aspect, in one possible implementation of the first aspect, the electrode is disposed on the outside of the second insulating sleeve, the first electrode of the at least two electrodes is disposed on one side of the flange, the second electrode of the at least two electrodes is disposed on one side of the second metal part, both the first electrode and the second electrode are electrically connected to external wiring, and the electrode arc assembly can be used to simulate an arc flashover fault along the outer surface of the second insulating sleeve.

[0011] In conjunction with the first aspect, in one possible implementation of the first aspect, an adjustable preset distance is provided between the electrodes.

[0012] A second aspect of this application provides an AC bushing arc test system for transformers, including the AC bushing arc test device for transformers as described above; a test circuit, the output terminal of which is electrically connected to the first and second electrodes of the arc electrode assembly, the test circuit including a test power supply, a switching assembly, and an adjustable current-limiting reactor connected in series, and the test circuit being used to apply a test current to the arc electrode assembly.

[0013] In conjunction with the second aspect, one possible implementation of the second aspect further includes: a voltage measuring device and a current measuring device connected to the test circuit, the voltage measuring device and the current measuring device being used to monitor the arc voltage and test current applied to the arc electrode assembly; the test circuit further includes a test transformer connected in series with the test power supply.

[0014] In conjunction with the second aspect, in one possible implementation of the second aspect, the test power source is an AC mains power source or an AC generator power source.

[0015] The technical solution provided in this application may include the following beneficial effects: This application discloses an arc testing device and system for AC bushings of transformers, applied to arc testing of high-voltage bushings. The high-voltage bushing includes a first tube body, a capacitor core covering the outside of the first tube body, a first metal part and a second metal part disposed at both ends of the first tube body, a first insulating sleeve and a second insulating sleeve for sealing the capacitor core, a final shield cover disposed on the side of the first insulating sleeve away from the first metal part, and an electrode arc assembly. The electrode arc assembly includes at least two electrodes and an arc wire for connecting the at least two electrodes. The at least two electrodes are disposed at preset fault simulation positions on the high-voltage bushing. The electrode arc assembly is used to generate a simulated arc after energization, which can accurately simulate multiple arc fault modes and improve the comprehensiveness and accuracy of the testing process.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0017] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0018] Figure 1 This is a schematic diagram of the structure of the AC bushing arc test device for transformers shown in the embodiments of this application; Figure 2 This is another structural schematic diagram of the AC bushing arc testing device for transformers shown in the embodiments of this application; Figure 3 This is another structural schematic diagram of the AC bushing arc testing device for transformers shown in the embodiments of this application; Figure 4 This is another structural schematic diagram of the AC bushing arc testing device for transformers shown in the embodiments of this application; Figure 5 This is another structural schematic diagram of the AC bushing arc testing device for transformers shown in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the AC bushing arc test system for transformers shown in the embodiments of this application.

[0019] Figure labels: 1. First metal part; 101. First electrode; 102. Second electrode; 2. First insulating sleeve; 3. Capacitor core; 4. First tube body; 5. End screen cover; 6. Flange; 7. Second metal part; 8. Second insulating sleeve; 9. Arc wire. Detailed Implementation

[0020] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0021] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a” and “the” as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0022] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] In related technologies, the traditional high-voltage AC bushing arc test method has the technical defect of being unable to accurately simulate various types of arc fault modes in actual working conditions. Due to the complex internal structure of the bushing, the existing test device is difficult to construct an adjustable electrode arrangement scheme in a closed space, which makes it impossible to accurately reproduce various key fault modes and affects the quantitative assessment of the bushing's explosion-proof and fire-resistant performance.

[0024] To address the aforementioned issues, this application provides an AC bushing arc testing device for transformers, which can accurately simulate various arc fault modes, thereby improving the comprehensiveness and accuracy of the testing process.

[0025] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0026] Figure 1This is a schematic diagram of the structure of an AC bushing arc test device for a transformer, as shown in an embodiment of this application.

[0027] See Figures 1-5 An AC bushing arc testing device for transformers is used for arc testing of high-voltage bushings. The high-voltage bushing includes a first tube body 4, a capacitor core 3 covering the outside of the first tube body 4, a first metal part 1 and a second metal part 7 disposed at both ends of the first tube body 4, a first insulating sleeve 2 and a second insulating sleeve 8 for sealing the capacitor core 3, a final shield cover 5 disposed on the side of the first insulating sleeve 2 away from the first metal part 1, and an electrode arc assembly. The electrode arc assembly includes at least two electrodes and an arc wire 9 for connecting the at least two electrodes. The at least two electrodes are disposed at preset fault simulation positions on the high-voltage bushing. The electrode arc assembly is used to generate a simulated arc after energization.

[0028] Specifically, a high-voltage bushing refers to an insulating assembly used in transformers to connect the winding leads to external leads. It includes a first tube body 4, which can be a rolled tube, a capacitor core 3, a first metal component 1, a second metal component 7, a first insulating sleeve 2, a second insulating sleeve 8, a final shield cover 5, and an electrode arc assembly. The first tube body 4 can be a hollow aluminum tube structure, with the capacitor core 3 wound around the outside of the first tube body 4, providing a realistic fault simulation environment for arc testing.

[0029] Specifically, the electrode arc assembly includes at least two electrodes and an arc wire 9 connecting the electrodes. The electrodes are positioned at preset fault simulation locations on the high-voltage bushing, such as the outer side of the capacitor core 3, the inner side of the insulating sleeve, or the area of ​​the end screen cover 5. The arc wire 9 connects the two electrodes and generates a simulated arc after energization. The electrodes are made of conductive metal material, and the arc wire 9 can be a fusible metal wire. The arc energy can be controlled by adjusting the electrode spacing. This assembly can accurately simulate arc faults at different locations on the bushing. The fault simulation location refers to the typical areas in the high-voltage bushing that are prone to arcing faults, including the interface between the outer side of the capacitor core 3 and the insulating sleeve, the area near the end screen cover 5, etc. The electrode arrangement in these locations can reproduce the arcing phenomenon caused by insulation deterioration or mechanical damage in actual operation, providing a targeted scenario for explosion-proof performance testing. By setting an adjustable electrode structure in the key fault area of ​​the high-voltage bushing, and combining it with the arc wire 9 to form a controllable arc path, a variety of typical arcing faults can be accurately simulated. It can perform targeted testing on the insulation weaknesses of different parts of the bushing, and provide standardized test conditions for evaluating the mechanical strength, explosion-proof performance and fire resistance of the bushing.

[0030] For example, the first metal part 1 and the second metal part 7 are respectively installed at both ends of the first tube body 4 for electrical connection. The first insulating sleeve 2 and the second insulating sleeve 8 are respectively fitted at both ends of the first tube body 4 for sealing the capacitor core 3. The end screen cover 5 is installed on the side of the first insulating sleeve 2 away from the first metal part 1 for further sealing and protection. The two electrodes are respectively installed at the preset fault simulation positions of the high-voltage bushing. For example, one electrode can be installed on the outside of the capacitor core 3 and the inside of the first insulating sleeve 2, and the other electrode can pass through the end screen cover 5 and connect to the outside. The arc wire 9 connects the two electrodes and generates an arc when energized. During the test, the high-voltage bushing is first installed vertically on the test bench, and then the electrodes are installed according to the preset positions and connected with the arc wire 9. Then the electrodes are connected to the external power supply. After energization, the arc wire 9 will generate an arc to simulate the arc fault inside the bushing. By adjusting parameters such as electrode spacing and current magnitude, the arc energy can be controlled to evaluate the performance of the bushing under different fault conditions.

[0031] In one possible implementation, one end of the electrode is disposed on the outside of the capacitor core 3 and located inside the first insulating sleeve 2. The first electrode 101 of the electrode passes through the first metal part 1, and one end of the second electrode 102 of the electrode passes through the end screen cover 5. The electrode arc assembly can be used to simulate the surface arc flashover fault of the air-side capacitor core 3 of the high-voltage bushing.

[0032] Specifically, the first electrode 101 is connected to the external wiring through a perforation in the top metal part, and the second electrode 102 passes through the end screen cover 5 to achieve external conductivity. The distance between the two electrodes is precisely controlled by a mechanical adjustment device, for example, the adjustment range is controlled between 5-50 mm. The arc wire 9 is made of copper alloy material with a diameter of 0.5 mm, and both ends are fixed to the electrode terminals by bolts. The annular space formed by the outer side of the capacitor core 3 and the inner side of the first insulating sleeve 2 serves as the arc channel. This space can be filled with sulfur hexafluoride gas medium. The electrodes are set on the outer side of the capacitor core 3 and the inner side of the first insulating sleeve 2, which can simulate the surface arc flashover fault of the air-side capacitor core 3 in the actual structure of the high-voltage bushing, improving the authenticity and accuracy of the test.

[0033] For example, both the first electrode 101 and the second electrode 102 are made of copper and have a diameter of 5 mm. One end of the first electrode 101 is inserted into the gap between the outer side of the capacitor core 3 and the inner side of the first insulating sleeve 2, and the other end protrudes from the through hole reserved in the first metal part 1. Similarly, one end of the second electrode 102 is inserted into the gap between the outer side of the capacitor core 3 and the inner side of the first insulating sleeve 2, and the other end protrudes from the through hole reserved in the end screen cover 5. A copper wire with a diameter of 0.1 mm is connected between the two electrodes as an arc wire 9. During the test, an electrode pair with a preset spacing is formed at the interface between the capacitor core 3 and the first insulating sleeve 2. A power frequency current of 10-20 kA is applied through an external test circuit. The arc wire 9 melts and generates an initial arc at the moment of energization. High-temperature plasma continuously discharges between the electrodes, forming a carbonization channel along the surface of the capacitor core 3. During the test, the insulating oil inside the bushing vaporizes and expands under the high temperature of the electric arc. A pressure sensor monitors the internal pressure changes in real time. The arc energy can be controlled within the range of 3-8 MJ by adjusting the electrode spacing. The test duration is 100-500 milliseconds. After the test, X-rays can be used to detect the deformation of the internal structure of the bushing and to check the leakage rate of the seals, comprehensively evaluating the bushing's explosion-proof performance under air-side surface flashover conditions.

[0034] In one possible implementation, the first electrode 101 of at least two electrodes is a first tube 4, and the second electrode 102 of at least two electrodes is disposed inside the end screen cover 5. The capacitor core 3 has a hollow area on one side corresponding to the second electrode 102. The arc wire 9 is connected to one side of the first electrode 101 and one side of the second electrode 102 through the hollow area. The electrode arc assembly can be used to simulate the main insulation breakdown arc fault of the capacitor core 3.

[0035] Specifically, the first tube 4, serving as the first electrode 101, is directly connected to the test circuit. The second electrode 102 is embedded inside the end cover 5. The area of ​​the capacitor core 3 corresponding to the second electrode 102 can be a cylindrical hollow structure. The arc wire 9 passes through the hollow area and is fixed to the inner wall of the first tube 4 and the end of the second electrode 102, respectively. The diameter of the hollow area matches the diameter of the arc wire 9, ensuring that the arc wire 9 is concentrated along a specific path inside the capacitor core 3 after energization. The second electrode 102 is connected to the external lead through the wiring port on the outside of the end cover 5, and the first electrode 101 is connected to the external lead through the through hole in the top metal part. The electrode spacing is achieved by adjusting the installation position of the second electrode 102 inside the end cover 5, with the adjustment range controlled between 5-20 mm.

[0036] For example, during the test, a conductive path is formed between the first tube 4 and the second electrode 102 via an arc wire 9. After energization, the arc wire 9 melts upon heating within the hollowed-out area of ​​the capacitor core 3, generating a high-temperature arc. The arc energy is concentrated inside the capacitor core 3, simulating the breakdown phenomenon of the main insulation material due to local defects or aging. The hollowed-out area confines the arc path to a specific depth inside the capacitor core 3, preventing the arc from spreading along the surface. The test current can be controlled within the range of 1-10 kA by adjusting the current-limiting reactor, the arc duration is set to 0.1-1 second, and the arc energy is verified by integral calculation to determine whether it reaches the preset 5 MJ threshold, thereby accurately evaluating the mechanical strength and sealing performance of the bushing under internal insulation breakdown conditions.

[0037] In one possible implementation, one end of the first electrode 101 of at least two electrodes is disposed on the outside of the capacitor core 3 and located on the inside of the second insulating sleeve 8, and the other end of the first electrode 101 extends out of the end screen cover 5. The second electrode 102 of at least two electrodes is a second metal piece 7. The electrode arc assembly can be used to simulate the surface arc flashover fault of the capacitor core 3 in the middle of the high voltage bushing.

[0038] Specifically, one end of the first electrode 101 extends into the annular gap between the capacitor core 3 and the second insulating sleeve 8, while the other end extends outward through a through hole on the end cover 5. The second electrode 102 is the second metal part 7, which serves as a conductive path and is electrically connected to the external terminals. The distance between the first electrode 101 and the second electrode 102 can be adjusted by adjusting the installation position of the end cover 5 or the electrode insertion depth, with an adjustment accuracy controlled within ±1mm. During the experiment, the arc wire 9 forms a conductive channel between the end of the first electrode 101 and the second metal part 7, and the arc energy is concentrated on the oil-immersed surface of the capacitor core 3. By adjusting the insertion depth of the first electrode 101, the relative distance between the arc starting point and the second metal part 7 is changed, so that the arc forms a stable flashover path along the oil-immersed surface of the capacitor core 3, which can accurately simulate the surface discharge phenomenon at the interface between the insulating oil and the solid medium in actual operation.

[0039] In one possible implementation, the high-voltage bushing also includes a flange 6, which is located on the side of the end cover 5 away from the first insulating sleeve 2.

[0040] Specifically, the end cover 5 is mounted on the flange 6 to form a sealing interface, and the spacing between the flange 6 and the first insulating sleeve 2 forms an axial pressure buffer zone. The installation position of the flange 6 is controlled by the axial distance, so that a discontinuous support section of a specific length is formed between the end cover 5 and the first insulating sleeve 2.

[0041] In one possible implementation, the electrodes are disposed on the outside of the second insulating sleeve 8, the first electrode 101 of at least two electrodes is disposed on one side of the flange 6, and the second electrode 102 of at least two electrodes is disposed on one side of the second metal part 7. Both the first electrode 101 and the second electrode 102 are electrically connected to external wiring. The electrode arc assembly can be used to simulate an arc flashover fault along the outer surface of the second insulating sleeve 8.

[0042] Specifically, when the electrodes are arranged outside the second insulating sleeve 8, the first electrode 101 is connected to the flange 6, and the second electrode 102 is connected to the bottom metal part. The two form a current path through external wiring. The electrode spacing can be adjusted according to test requirements. The arc wire 9 is connected between the two electrodes to form an arc path. The flange 6 serves as a fixed support structure to ensure the electrodes remain stable during the test. The second metal part 7 acts as a conductive component, forming a closed circuit with the external circuit. During the test, an external power supply applies current to the first electrode 101 on the flange 6 side and the second electrode 102 on the second metal part 7 side through leads. The arc wire 9 generates an arc between the electrodes. The arc energy is concentrated on the outer surface of the second insulating sleeve 8, simulating a surface flashover fault in this area during actual operation. By adjusting the electrode spacing and test current parameters, the magnitude of the arc energy can be precisely controlled, allowing for testing of the mechanical strength and explosion-proof capability of the second insulating sleeve 8 under arc action. The fixing function of the flange 6 ensures the stability of the electrode position, preventing arc path deviation due to mechanical vibration. The second metal part 7 acts as a conductive end, forming a low-impedance connection with the external circuit to ensure accurate application of the test current.

[0043] In one possible implementation, an adjustable preset distance is provided between the electrodes.

[0044] Specifically, the preset distance can be set according to actual needs, for example, the adjustment range of the electrode spacing can be set from 5 mm to 50 mm.

[0045] This application discloses an AC bushing arc testing device for transformers, applied to arc testing of high-voltage bushings. The high-voltage bushing includes a first tube body 4, a capacitor core 3 covering the outside of the first tube body 4, a first metal part 1 and a second metal part 7 disposed at both ends of the first tube body 4, a first insulating sleeve 2 and a second insulating sleeve 8 for sealing the capacitor core 3, a final shield cover 5 disposed on the side of the first insulating sleeve 2 away from the first metal part 1, and an electrode arc assembly. The electrode arc assembly includes at least two electrodes and an arc wire 9 for connecting the at least two electrodes. The at least two electrodes are disposed at preset fault simulation positions on the high-voltage bushing. The electrode arc assembly is used to generate a simulated arc after energization, which can accurately simulate multiple arc fault modes and improve the comprehensiveness and accuracy of the testing process.

[0046] See Figure 6This application also provides an AC bushing arc test system for transformers, including the AC bushing arc test device for transformers as described above; a test circuit, the output terminal of which is electrically connected to the first electrode 101 and the second electrode 102 of the arc electrode assembly; the test circuit includes a test power supply, a switching assembly, and an adjustable current-limiting reactor connected in series; the test circuit is used to apply a test current to the arc electrode assembly.

[0047] Specifically, the test power supply can provide power frequency energy of different capacity levels. The switching assembly includes circuit breakers and disconnectors for controlling the on / off state of the test circuit and ensuring safety isolation. An adjustable current-limiting reactor changes the circuit impedance by adjusting the inductance value, enabling continuous adjustment of the test current from hundreds to thousands of amperes. The output of the test circuit is connected to two electrodes mounted on a high-voltage bushing via a copper busbar or high-voltage cable, forming a closed current path. This allows for precise control of the amplitude and duration of the test current, effectively simulating arc faults of different energy levels in actual operation. By adjusting the reactor parameters, arc energy loading under various operating conditions can be achieved, ensuring that the test conditions are identical to real fault scenarios. Among these, in Figure 6 In this diagram, P represents AC power (AC grid power or generator); CB represents circuit switch; DS represents disconnect switch; IT represents isolation transformer; SCB represents synchronous switch; XL represents adjustable current-limiting reactor; VT represents voltage measuring device; CT represents current measuring device; and TS represents high-voltage bushing.

[0048] For example, after the test power supply is connected to the circuit via the switching assembly, an adjustable current-limiting reactor can be used to match the impedance, establishing a power frequency current that meets preset parameters between the electrodes. When the arc wire 9 melts between the electrodes, the arc energy is determined by both the amplitude of the test current and the arcing time. The inductance value of the adjustable current-limiting reactor is adjusted by changing the winding taps or the air gap in the core, for example, by using a multi-position tap changer to switch the number of winding turns, allowing the test current to be adjusted in stages from 20kA to 63kA. During the test, the switching assembly first closes the isolating switch to establish a preparatory state, and then the circuit is instantaneously connected through the circuit breaker. The synchronous switch precisely controls the arcing time within the range of 100ms to 500ms, ensuring that the calculated arc energy value is equivalent to the actual fault condition. The test transformer connected in series in the circuit is used to increase the power supply voltage level to match the insulation structure requirements of the high-voltage bushing, for example, boosting the 10kV power supply to 80% of the bushing's rated voltage for testing.

[0049] In one possible implementation, the system further includes: a voltage measuring device and a current measuring device connected to the test circuit, the voltage measuring device and the current measuring device being used to monitor the arc voltage and test current applied to the arc electrode assembly; the test circuit also includes a test transformer connected in series with the test power supply.

[0050] Specifically, a voltage measuring device is connected in parallel across the arc electrode assembly to collect instantaneous waveform data of the arc voltage; a current measuring device is connected in series in the test circuit to record the real-time amplitude and phase of the test current; the primary winding of the test transformer is connected to the test power supply, and the secondary winding is connected to an adjustable current-limiting reactor through a switching assembly to boost the test voltage to a preset level.

[0051] Specifically, during the test, the AC power output from the test power supply is stepped up by the test transformer and then enters the adjustable current-limiting reactor through a closed switching assembly. The reactance value is adjusted to control the circuit impedance, ensuring the output current reaches the preset test value. The voltage measuring device acquires the voltage signal between the two electrodes in real time using a high-impedance voltage divider, while the current measuring device obtains the circuit current parameters using a Rogowski coil or current transformer. The signals from both measuring devices are synchronously input into the data acquisition system. Through integration, the product of voltage and current is integrated over time to accurately calculate the arc energy. The test transformer's turns ratio is adjusted to match the bushing testing requirements of different voltage levels, ensuring the accuracy of the applied arc energy.

[0052] In one possible implementation, the test power source is an AC mains power source or an AC generator power source.

[0053] Specifically, the AC grid power supply directly obtains power frequency AC by connecting to the existing power system, and its voltage waveform is consistent with the actual operating conditions of the power grid; the AC generator power supply generates power frequency AC through an independent generator set, suitable for test sites without grid connection. Both power supplies are connected to the test circuit through an adjustable current-limiting reactor. The reactor impedance value is adjusted according to the test current requirements to ensure that the test current waveform meets the preset parameters.

[0054] For example, when the AC mains power supply is running, the mains voltage is connected to the test circuit through an isolation transformer. The secondary side of the isolation transformer is connected in series with a synchronous switch. When the synchronous switch is closed, the test current is applied to the electrode assembly through a current-limiting reactor. When the AC generator power supply is running, the generator output is connected to the test circuit through a circuit breaker. The output voltage amplitude is controlled by adjusting the generator excitation current. Voltage measuring devices for both power supplies collect the voltage signals across the electrodes in real time, and current measuring devices are connected in series in the circuit to collect the test current signal. The arc energy is calculated by integration. For example, when using a 10MVA AC generator, the output voltage can be adjusted to 12kV. With the help of a current-limiting reactor, the test current is controlled within 2kA for 0.5 seconds, generating 5MJ of arc energy. By limiting the power supply type and its connection method, the power frequency characteristics of the test current are ensured to be consistent with the actual fault current.

[0055] This application is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of this application is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of this application.

[0056] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0057] The above are merely specific embodiments of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. An alternating current bushing arc test device for transformers, characterized in that, The application relates to an arc test applied to a high-voltage bushing, the high-voltage bushing comprising a first tube body, a capacitor core wrapped outside the first tube body, a first metal piece and a second metal piece arranged at two ends of the first tube body, a first insulation sleeve and a second insulation sleeve used for sealing the capacitor core, a terminal screen cover arranged at a side of the first insulation sleeve away from the first metal piece, and an electrode arc assembly. The electrode arc assembly comprises at least two electrodes and an arc wire used for connecting the at least two electrodes, the at least two electrodes are arranged at preset fault simulation positions on the high-voltage bushing, and the electrode arc assembly is used for generating a simulated arc after being powered on.

2. The AC bushing arc testing device for transformers according to claim 1, characterized in that, One end of the electrode is arranged outside the capacitor core and inside the first insulation sleeve, a first electrode of the electrode penetrates out of the first metal piece, one end of a second electrode of the electrode penetrates out of the terminal screen cover, and the electrode arc assembly can be used for simulating an along-surface arc flashover fault of an air side capacitor core of the high-voltage bushing.

3. The AC bushing arc testing device for transformers according to claim 1, characterized in that, A first electrode of the at least two electrodes is the first tube body, a second electrode of the at least two electrodes is arranged inside the terminal screen cover, a hollow region is arranged at a side of the capacitor core corresponding to the second electrode, the arc wire is connected to one side of the first electrode and one side of the second electrode through the hollow region, and the electrode arc assembly can be used for simulating a main insulation breakdown arc fault of the capacitor core.

4. The AC bushing arc testing device for transformers according to claim 1, characterized in that, One end of a first electrode of the at least two electrodes is arranged outside the capacitor core and inside the second insulation sleeve, the other end of the first electrode penetrates out of the terminal screen cover, a second electrode of the at least two electrodes is the second metal piece, and the electrode arc assembly can be used for simulating an along-surface arc flashover fault of a middle side capacitor core of the high-voltage bushing.

5. The AC bushing arc testing device for transformers according to claim 1, characterized in that, The high-voltage bushing further comprises a flange, and the flange is arranged at a side of the terminal screen cover away from the first insulation sleeve.

6. The AC bushing arc testing device for transformers according to claim 5, characterized in that, The electrode is arranged outside the second insulation sleeve, a first electrode of the at least two electrodes is arranged at one side of the flange, a second electrode of the at least two electrodes is arranged at one side of the second metal piece, the first electrode and the second electrode are electrically connected to an external wiring, and the electrode arc assembly can be used for simulating an along-surface arc flashover fault outside the second insulation sleeve.

7. An AC bushing arc testing device for transformers according to any of claims 2-6, characterized in that, An adjustable preset distance is arranged between the electrodes.

8. An AC bushing arc test system for transformers, characterized by, The application further relates to an arc test device for an alternating-current bushing of a transformer. An output end of a test loop is electrically connected to first and second electrodes of the arc electrode assembly, the test loop comprises a test power supply, a switch assembly and an adjustable current-limiting reactor connected in series, and the test loop is used for applying a test current to the arc electrode assembly. Further, the application further relates to 9. The alternating current bushing arc testing system for transformers of claim 8, wherein, a voltage measuring device and a current measuring device connected to the test loop, the voltage measuring device and the current measuring device are used for monitoring an arc voltage and a test current applied to the arc electrode assembly; and the test loop further comprises a test transformer connected in series with the test power supply. ​ 10. The AC bushing arc testing system for transformers of claim 8, wherein, The test power source is an AC grid power source or an AC generator power source. The test power source is an AC grid power source or an AC generator power source.

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