Testing device and measuring method for measuring arc characteristics of oil-less bushing of transformer

Abstract

The invention discloses a test device and a measurement method for measuring the arc characteristic of a transformer oil-less bushing, and relates to the technical field of arc characteristic measurement. By arranging a test cavity for simulating a real transformer oil-less bushing and cooperating with an electrode unit, the arc discharge environment of a narrow space in the oil-less bushing can be restored more truly; meanwhile, the multi-parameter detection unit is arranged, signals of the multi-parameter detection unit are converged into the same data acquisition device, the problem that in the prior art, electric parameters and non-electric parameters of an electric arc are difficult to measure synchronously is effectively solved, and a reliable experimental platform is provided for deeply researching the characteristics of the electric arc and revealing the internal incidence relation among the parameters; two methods of direct measurement and calculation measurement are adopted for the gas production rate, the accuracy of measurement data can be verified, and system errors possibly existing in a single measurement method are eliminated, so that more reliable and accurate gas production rate data are obtained, and the credibility of an experimental result is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of arc characteristic measurement technology, and in particular to a test device and measurement method for measuring the arc characteristics of transformer low-oil bushings. Background Technology

[0002] As one of the main substation equipment in the power system, the operation of oil-immersed power transformers is closely related to the safety of the entire power grid. Bushings, as electrical devices that deliver voltage and carry large currents, are widely used in transmission lines. They are not only important accessories of transformers but also crucial transmission and transformation equipment. High-voltage bushings for 110kV and above oil-immersed transformers mostly use oil-paper capacitor bushings. Their internal structure consists of a capacitor core (alternating rolls of insulating paper and aluminum foil), with only a small amount of insulating oil filled between the core and the porcelain bushing for auxiliary insulation and heat dissipation. The oil level only needs to be maintained at 1 / 2 to 2 / 3 of the observation window. In the event of an arc fault, bushings with less oil (such as oil-paper capacitor bushings) pose a significantly greater danger than those with more oil. Bushings with less oil have a smaller internal oil volume and narrower oil channels. During an arc fault, the insulating oil decomposes instantaneously, generating large amounts of hydrogen, hydrocarbon gases, and high-temperature plasma. Due to the limited oil space, the gas cannot diffuse effectively, leading to a rapid increase in pressure, much faster than the gas buffer space of bushings with more oil. If the sealing structure fails or the pressure relief device does not activate in time, the bushing is prone to rupture, ejecting a high-temperature oil-gas mixture. Contact between the high-temperature oil-gas and air may trigger a deflagration, leading to a transformer fire. Statistics show that bushing failures account for 50%-72% of transformer fires, and bushings with low oil content are more susceptible to triggering such chain reactions due to their smaller oil volume and more intense pressure release.

[0003] However, current research on bushing faults focuses on oil-filled bushings, with limited experimental research on arc faults in the internal shield of low-oil bushings. Yet, low-oil bushings are used at higher voltage levels than oil-filled bushings, and their internal structure is more complex, making arc faults more destructive and dangerous. Existing technologies struggle to address the complexity and uncertainty of arc parameters within low-oil bushings, and cannot simultaneously measure multiple key parameters, particularly lacking direct measurement of gas production. Summary of the Invention

[0004] In view of the problems existing in the above or prior art, the present invention is proposed.

[0005] Therefore, the purpose of this invention is to provide a test device for measuring the arc characteristics of transformer bushings with less oil. This device addresses the problem that traditional test devices are unable to handle the complexity and uncertainty of arc parameters inside bushings with less oil, cannot simultaneously measure multiple key parameters, and especially lack direct measurement of gas production.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a test device for measuring the arc characteristics of a transformer bushing with low oil content, comprising a test chamber, wherein the test chamber forms a sealed space for accommodating insulating oil and generating an arc; an electrode unit disposed within the test chamber for generating an arc; and a multi-parameter detection unit disposed on one side of the test chamber for measuring multiple parameters during the arc generation process; wherein the output terminal of the multi-parameter detection unit is connected to the same data acquisition device for synchronous acquisition of multiple parameters.

[0007] As a preferred embodiment of the test device for measuring the arc characteristics of a transformer with low oil bushing according to the present invention, the multi-parameter detection unit includes: a gas phase pressure measuring unit disposed at the top of the test chamber, the gas phase pressure measuring unit including a first pressure sensor for measuring the gas phase pressure generated by the arc; a gas phase temperature measuring unit disposed at the top of the test chamber, the gas phase temperature measuring unit including a thermometer for monitoring the gas temperature generated by the arc; and a liquid phase pressure measuring unit disposed in the middle of the test chamber, the liquid phase pressure measuring unit including a second pressure sensor and a third pressure sensor for measuring the liquid phase pressure generated by the arc.

[0008] By using the gas phase pressure measurement unit and gas phase temperature measurement unit set at the top of the test chamber, the pressure surge and temperature change of the gas phase space after the arc discharge can be captured; the liquid phase pressure measurement unit set in the middle of the test chamber, using dual pressure sensors, can effectively measure the pressure generated by the arc in the oil and capture the propagation process of the pressure wave in the oil.

[0009] As a preferred embodiment of the test device for measuring the arc characteristics of transformer low-oil bushings according to the present invention, the multi-parameter detection unit further includes an arc gas generation measurement unit, which includes a gas generation collection device connected to the gas phase space of the test chamber via a pipeline; and a flow measurement device installed on the pipeline for directly measuring the volume of gas generated after arc discharge.

[0010] The test chamber is connected to the gas collection device via a pipeline, and a flow measurement device is installed on the pipeline to achieve direct measurement of the total amount of gas generated by the decomposition of insulating oil by electric arc.

[0011] As a preferred embodiment of the test device for measuring the arc characteristics of the transformer's low-oil bushing, the device further includes an arc process observation window located in the middle of the test chamber; the multi-parameter detection unit also includes a high-speed camera device, the lens of which is aimed at the arc process observation window to record the morphological evolution of the arc bubbles.

[0012] The arc process observation window allows researchers to directly observe the entire process of the arc igniting in oil, the generation, expansion, collapse, and interaction with the surrounding insulating structure. Combined with a high-speed camera, this dynamic process can be recorded in video form.

[0013] As a preferred embodiment of the test device for measuring the arc characteristics of transformer bushings with less oil as described in this invention, the electrode unit includes an upper electrode rod disposed inside the upper half of the test chamber and a lower electrode rod disposed inside the lower half of the test chamber.

[0014] By employing upper and lower electrode rods, it is convenient to install samples such as arc-starting wires, ensuring that the arc can be stably generated at the predetermined position. The structure of the electrode rods also facilitates the connection with the external arc test platform, ensuring a stable input of high current and high energy, which is the fundamental guarantee for realizing high-energy arc discharge. At the same time, it also ensures that the generation environment and occurrence mechanism of the test arc are highly consistent with the actual fault conditions, greatly improving the effectiveness and reliability of the simulation results of the test device.

[0015] As a preferred embodiment of the test device for measuring the arc characteristics of transformer bushings with less oil as described in this invention, it further includes a gas pressure relief unit disposed in the middle of the test chamber for releasing high-pressure gas inside the test chamber.

[0016] After an electric arc discharge, a large amount of high-pressure gas accumulates inside the test chamber. Directly opening the valves of the gas generation measurement unit poses a safety risk of pipe rupture and gas ejection causing injury. The gas pressure relief unit allows for the safe and controllable release of high-pressure gas within the chamber before measuring the gas generation, reducing the pressure to a safe level. This not only protects the experimental equipment from damage but also ensures the safety of the personnel involved.

[0017] As a preferred embodiment of the test device for measuring the arc characteristics of transformer bushings with low oil content according to the present invention, it further includes an oil injection hole at the top of the test chamber, an oil drain hole at the bottom of the test chamber, and flanges at both ends of the test chamber.

[0018] The oil injection hole facilitates the injection of insulating oil into the test chamber; the oil drain hole facilitates the discharge of waste oil from the chamber after the experiment, making it convenient for cleaning and maintenance of the device; and the flanges at both ends provide a reliable seal, ensuring the airtightness and watertightness of the test chamber under high pressure.

[0019] Another objective of this invention is to provide a measurement method for measuring the arc characteristics of a transformer low-oil bushing, wherein: measuring instruments in a multi-parameter detection unit are installed, arranged, and connected, and the airtightness, watertightness, and normality of signal transmission of the detection device are measured.

[0020] An arc-starting wire is installed between the upper and lower electrode rods; the electrode unit is then connected to the arc test platform.

[0021] Insulating oil is injected through the oil injection hole, leaving space for gas, and the initial gas phase temperature and pressure are recorded;

[0022] An electric arc is generated by controlling an electric arc test platform, and data during the arc generation process is collected using a multi-parameter detection unit.

[0023] After the arc discharge is completed and the temperature and pressure of the gas phase space inside the test chamber stabilize, the gas production is measured.

[0024] As a preferred embodiment of the measurement method for measuring the arc characteristics of the transformer low-oil bushing described in this invention, the gas production is obtained by direct measurement or by calculating the gas phase temperature and pressure after discharge in combination with the initial gas phase temperature and pressure recorded before the experiment.

[0025] The beneficial effects of this plan are:

[0026] This invention, by setting up a test chamber simulating a real transformer's low-oil bushing and using an electrode unit to generate an electric arc, can more realistically reproduce the arc discharge environment within the confined space of the low-oil bushing. Simultaneously, a multi-parameter detection unit is incorporated, with signals from these units ultimately converging into a single data acquisition device. This effectively solves the problem in existing technologies of simultaneously measuring electrical parameters (such as current and voltage) and non-electrical parameters (such as pressure, temperature, and gas generation) of the arc. This provides a reliable experimental platform for in-depth research into arc characteristics and revealing the intrinsic relationships between various parameters. Furthermore, by employing both direct measurement and computational measurement methods for gas generation, the accuracy of the measurement data can be verified, eliminating potential systematic errors associated with single measurement methods. This results in more reliable and accurate gas generation data, significantly improving the credibility of the experimental results. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the overall structure of the test device for measuring the arc characteristics of transformer bushings with low oil content.

[0029] Figure 2 A schematic diagram of the overall structure of the upper part of the test device for measuring the arc characteristics of transformer bushings with less oil.

[0030] Figure 3A schematic diagram of the cross-sectional installation of the test device for measuring the arc characteristics of transformer low-oil bushings when an arc fault occurs in the low-oil bushing panel.

[0031] Figure 4 A schematic diagram of the integrated installation of the test device for measuring the arc characteristics of transformer low-oil bushings when an arc fault occurs in the low-oil bushing panel.

[0032] Figure 5 A schematic diagram showing the installation of the arc-starting wire when an arc fault occurs in the oil-less bushing screen of a transformer, for the test device used to measure the arc characteristics of the oil-less bushing.

[0033] 1. Test chamber; 21. Upper electrode rod mounting hole; 22. Lower electrode rod mounting hole; 3. Gas phase pressure measurement unit mounting hole; 4. Gas phase temperature measurement unit mounting hole; 5. Liquid phase pressure measurement unit mounting hole; 6. Arc gas generation measurement unit mounting hole; 7. Arc process observation window; 8. Gas pressure relief unit mounting hole; 91. Oil injection hole; 92. Oil drain hole; 10. Flange; 111. Guide rod simulation tube; 112. Upper electrode rod; 113. Insulating oil paperboard; 114. Arc ignition wire; 115. Current conductor; 116. Lower electrode rod. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0037] This invention provides a test apparatus for measuring the arc characteristics of a transformer with low oil bushing. The multi-parameter detection unit mentioned in this invention may vary depending on the measuring instrument. Appropriate mounting holes need to be selected based on the measuring instrument, and corresponding mounting holes need to be drilled on the test apparatus. The required measuring instrument is installed and fixed through these mounting holes. The figure shows the mounting holes for the multi-parameter detection unit; the measuring instrument is an existing device and is therefore not shown.

[0038] The content of this invention is a study on the occurrence of arc faults in oil-insulated bushings.

[0039] Example 1

[0040] Reference Figures 1-2 This is the first embodiment of the present invention, which provides a test device for measuring the arc characteristics of a transformer bushing with low oil content. The device includes a test chamber 1, which forms a sealed space inside the test chamber 1 for accommodating insulating oil and generating an arc; an electrode unit disposed within the test chamber 1 for generating an arc; and a multi-parameter detection unit disposed on one side of the test chamber 1 for measuring multiple parameters during the arc generation process. The output of the multi-parameter detection unit is connected to the same data acquisition device to achieve synchronous acquisition of multiple parameters.

[0041] It should be noted that the internal structure of test chamber 1 is designed to simulate the internal structure of a transformer bushing with low oil content, rather than the traditional cylindrical structure. This allows the experimental measurement results to provide a reference for the improved design of the bushing structure. Test chamber 1 is equipped with a simulated insulating component and a simulated guide tube 111 to simulate an arc fault on the surface of the oil-impregnated paperboard inside the bushing with low oil content, thus recreating the arc fault environment. The insulating component can be made of insulating paperboard 113. The multiple parameters detected by the multi-parameter detection unit include at least: arc current, arc voltage, liquid phase pressure, gas phase pressure, and gas phase temperature. The data collected by the multi-parameter detection unit are connected to the same oscilloscope, simultaneously recording the changes in pressure, gas production, and arc voltage and current during arc generation inside test chamber 1.

[0042] Example 2

[0043] Reference Figures 1-2 This is the second embodiment of the present invention. The difference between this embodiment and the previous embodiment is that the multi-parameter detection unit includes: a gas phase pressure measurement unit disposed at the top of the test chamber 1, the gas phase pressure measurement unit including a first pressure sensor for measuring the gas phase pressure generated by the electric arc; a gas phase temperature measurement unit disposed at the top of the test chamber 1, the gas phase temperature measurement unit including a thermometer for monitoring the gas temperature generated by the electric arc; and a liquid phase pressure measurement unit disposed in the middle of the test chamber 1, the liquid phase pressure measurement unit including a second pressure sensor and a third pressure sensor for measuring the liquid phase pressure generated by the electric arc.

[0044] It should be noted that the first sensor is a piezoelectric pressure sensor; the thermometer is a high-precision bimetallic thermometer; the liquid phase pressure measurement unit is set at the horizontal plane of the arc discharge in the middle of the cavity; the second sensor is a fiber optic pressure sensor; and the third sensor is a high-frequency pressure sensor. Since the arc channel is not necessarily straight, and even with the arc-starting wire 114 there is randomness, two sensors are required for measurement. The arc discharge will create a high electromagnetic environment, requiring two sensors with different principles to measure, which can ensure the accuracy of the measurement. The gas phase pressure measurement unit is installed in the gas phase pressure measurement unit mounting hole 3, the gas phase temperature measurement unit is installed in the gas phase temperature measurement unit mounting hole 4, and the liquid phase pressure measurement unit is installed in the liquid phase pressure measurement unit mounting hole 5.

[0045] Furthermore, the multi-parameter detection unit also includes an arc gas generation measurement unit, which includes: a gas generation collection device, which is connected to the gas phase space of the test chamber 1 through a pipeline; and a flow measurement device installed on the pipeline, which is used to directly measure the volume of gas generated after the arc discharge.

[0046] It should be noted that a gas collection device is included to collect and centrally process the gas generated after the experiment, preventing gas from affecting the safety of experimental personnel and polluting the environment. For ease of experimentation, the experimental apparatus may also include a temperature control unit or a waiting unit to restore the gas phase temperature inside the experimental chamber 1 to its initial state before measurement. The gas collection device can be a gas collection bag or other exhaust gas treatment equipment. The arc gas generation measurement unit is installed inside the arc gas generation measurement unit mounting hole 6.

[0047] Example 3

[0048] Reference Figures 1-4 This is the third embodiment of the present invention. Unlike the previous two embodiments, this embodiment also includes an arc process observation window 7 disposed in the middle of the test chamber 1. The multi-parameter detection unit also includes a high-speed camera device. The lens of the high-speed camera device is aimed at the arc process observation window 7 to record the morphological evolution process of the arc bubble.

[0049] Furthermore, the electrode unit includes an upper electrode rod 112 disposed inside the upper half of the test chamber 1 and a lower electrode rod 116 disposed inside the lower half of the test chamber 1.

[0050] It should be noted that the high-speed camera device uses a high-speed camera; a high-voltage measuring probe is connected to the upper electrode rod 112 to measure the arc voltage waveform, and a Rogowski coil is nested on the lower electrode rod 116 to measure the arc current in the oil; additionally, an arc-starting wire 114 is required to connect the upper electrode rod 112 and the lower electrode rod 116 via a current conductor 115 to trigger an arc fault on the surface of the oil-impregnated cardboard. The upper electrode rod 112 is installed in the upper electrode rod 112 mounting hole 21, and the lower electrode rod 116 is installed in the lower electrode rod 116 mounting hole 22.

[0051] Furthermore, it also includes a gas pressure relief unit located in the middle of the test chamber 1, used to release the high-pressure gas inside the test chamber 1.

[0052] It should be noted that the gas pressure relief unit includes a pressure relief valve and a pressure relief pipeline. One end of the pressure relief pipeline is connected to the gas phase space of test chamber 1, and the other end is connected to a safety handling device. The pressure relief valve automatically opens when the internal pressure exceeds the preset safety value, used to release high-pressure gas in the chamber before gas generation measurement or in emergency situations to prevent the chamber from rupturing. An adjustable pressure threshold pressure relief valve is selected. The gas pressure relief unit is installed inside the gas pressure relief unit mounting hole 8.

[0053] Furthermore, it also includes an oil injection hole 91 located at the top of the test chamber 1, an oil drain hole 92 located at the bottom of the test chamber 1, and flanges 10 located at both ends of the test chamber 1.

[0054] It should be noted that in the experiment, the oil injection hole 91 is used to inject insulating oil; the oil drain hole 92 is used to drain insulating oil; and the flange 10 is used for connection and sealing.

[0055] A support frame is provided outside the test chamber 1 to facilitate support and placement.

[0056] Example 4

[0057] Reference Figures 1-4 This is the fourth embodiment of the present invention. Unlike the previous three embodiments, this embodiment provides a method for measuring the arc characteristics of a transformer low-oil bushing, including:

[0058] S100: Install, arrange, and connect the measuring instruments in the multi-parameter detection unit to detect the airtightness, watertightness, and normal signal transmission of the device;

[0059] It should be noted that the measuring instruments in the multi-parameter detection unit are installed, arranged, and connected as follows: the gas phase pressure measuring unit, the arc gas generation measuring unit, and the gas phase temperature measuring unit are installed at the top of the test chamber 1, and the liquid phase pressure measuring unit is installed in the middle of the test chamber 1, that is, at the horizontal plane of the arc discharge. The high-speed camera is positioned directly opposite the observation window of the arc discharge process. After installation, arrangement, and connection, the airtightness, watertightness, and signal transmission of the detection device are ensured to be normal. If oil filling is required for testing, the outer cover of the oil filling hole 91 is opened, oil is injected into the chamber to the specified height, and then a sealing test is performed. The specified height is adjusted according to actual needs, and will vary depending on the oil level in the sleeve during the test. After the test, the oil in the chamber is drained.

[0060] S200: An arc-starting wire 114 is installed between the upper electrode rod 112 and the lower electrode rod 116; the electrode unit is connected to the arc test platform;

[0061] It should be noted that, in the specific experiment, the arc-starting wire 114 is made of copper wire. The arc-starting copper wire is fixed between two current-carrying wires 115, and then the two current-carrying wires 115 are connected to the upper electrode rod 112 and the lower electrode rod 116 respectively through the arc discharge process observation window. In this embodiment, the test sample simulates the arc barrier on the surface of an oil-impregnated cardboard inside a low-oil bushing. The current-carrying wires 115 are used to connect the electrode unit to the arc-starting wire 114 to generate a high-energy arc. The upper electrode rod 112 and the lower electrode rod 116 of the connection device are connected to the arc test platform to check whether the electrical distance of the lines meets the requirements of the high-voltage experiment.

[0062] S300: Insulating oil is injected through the oil injection hole 91, gas space is reserved, and the initial gas phase temperature and pressure are recorded;

[0063] It should be noted that transformer oil was used as the insulating oil in the specific experiment. The transformer oil was injected into the device through the oil injection hole 91 using an oil pump. Sufficient space was reserved for measuring the air pressure. The oil inlet valve and the air extraction valve were closed. The temperature and pressure of the gas space in the chamber were recorded before the experiment.

[0064] S400: Generates an electric arc by controlling the electric arc test platform and collects data during the arc generation process using a multi-parameter detection unit;

[0065] It should be noted that the charging circuit is controlled by the arc test platform to charge the capacitor. Once the charging voltage reaches the required value, the charging stops and the charging circuit is disconnected. At this time, the test circuit is in a ready-to-trigger state. The thyristor switch is triggered, and a large current is instantaneously applied to the test chamber 1. The test data is collected and saved simultaneously. The final pressure, arc voltage, and current waveforms obtained by the multi-parameter detection unit are recorded by the oscilloscope, realizing the synchronous measurement of pressure, arc voltage, and current waveforms during the development of bushing arc fault.

[0066] S500: After the arc discharge is completed and the temperature and pressure of the gas phase space inside the test chamber 1 are stable, measure the gas production.

[0067] Furthermore, the gas production rate can be obtained through direct measurement or calculated by combining the gas phase temperature and pressure after discharge with the initial gas phase temperature and pressure recorded before the experiment.

[0068] It should be noted that after the arc discharge is completed and the temperature and pressure inside the test chamber 1 are stable, the gas collection bag is connected to the flow meter, the valve of the flow meter connection pipe is opened, and the gas production is directly measured.

[0069] Besides directly measuring the gas production, the gas production of the arc discharge can also be calculated by combining the temperature and pressure measurements of the gas phase after the discharge with the gas phase temperature and pressure recorded before the experiment; according to the ideal gas law:

[0070] PV = nRT

[0071] The formula for calculating gas production is obtained by transforming the above formula as follows:

[0072]

[0073] Where ΔV is the gas production rate normalized to standard conditions, in L; p1 and p2 are the steady-state gas pressures before and after the experiment, in kPa; T1 and T2 are the steady-state temperatures before and after the experiment, in K; p0 is the standard pressure of 101.325 kPa; and T0 is the standard temperature of 273.15 K. V is the gas volume. Since the gas volume is relatively large when measuring the gas production rate, and the cavity is generally made of rigid material, the effect of cavity deformation on the cavity volume can be ignored. In addition, since the compressibility of oil is much smaller than that of gas, the change in gas volume before and after the experiment can be ignored. V is the gas volume reserved before the experiment.

[0074] In this embodiment, gas production measurement and calculation are performed simultaneously using both direct measurement and computational measurement. The direct measurement method fully considers the influence of temperature and pressure on the gas volume; therefore, the gas production volume must be measured only after the temperature returns to its pre-experimental temperature to ensure accuracy. To prevent excessive gas pressure leading to pipe bursts when the gas valve of the gas production measurement unit is opened, a pressure relief valve is installed to completely release the gas, preventing damage to the apparatus and injury to operators during the experiment. The computational measurement method uses the ideal gas state equation to calculate the gas production volume based on the temperature and pressure changes in the reserved gas space before and after the arc discharge. Both methods are used together to measure the gas production volume, ensuring its accuracy.

[0075] Table 1 shows the gas production measurement results of this experiment:

[0076] Table 1 Gas production measurement results

[0077] Calculated value Measured values deviation 0.06457 0.061 0.00357 0.06549 0.061 0.00449 0.06647 0.062 0.00447

[0078] This invention proposes for the first time a joint detection method for arc parameters during a simulated arc fault inside a low-oil bushing. Based on the multi-parameter sensing system of the experimental platform, the pressure, gas production volume, and morphological changes of bubbles in the oil during the simulated arc occurrence process in the low-oil bushing can be obtained separately. This invention innovatively designs the experimental apparatus according to a 1:1 model of the bushing. To recreate the actual fault situation, an oil-paper screen is added, which differs from the cylindrical and cuboid structures of previous transformer tanks, and can simulate the characteristics of arc pressure inside the bushing structure. This method uses dual pressure sensors to simultaneously measure the arc liquid phase pressure, combined with observation of arc bubble morphology, to address the randomness of the arc channel and the irregularity of the arc bubbles, providing a basis for exploring the mechanism of arc pressure propagation.

[0079] Importantly, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A test apparatus for measuring the arc characteristics of a transformer bushing with low oil content, characterized in that, include: The test chamber (1) has a sealed space inside for containing insulating oil and generating an electric arc. An electrode unit is disposed within the test chamber (1), the electrode unit being used to generate an electric arc; A multi-parameter detection unit is set on one side of the test chamber (1), and the multi-parameter detection unit is used to measure multiple parameters during the arc generation process; The output of the multi-parameter detection unit is connected to the same data acquisition device to achieve synchronous acquisition of multiple parameters.

2. The test apparatus for measuring the arc characteristics of transformer low-oil bushings as described in claim 1, characterized in that, The multi-parameter detection unit includes: A gas phase pressure measuring unit is set at the top of the test chamber (1). The gas phase pressure measuring unit includes a first pressure sensor for measuring the gas phase pressure generated by the electric arc. A gas phase temperature measuring unit is installed at the top of the test chamber (1). The gas phase temperature measuring unit includes a thermometer for monitoring the gas temperature generated by the electric arc. The liquid phase pressure measurement unit is located in the middle of the test chamber (1). The liquid phase pressure measurement unit includes a second pressure sensor and a third pressure sensor, which are used to measure the liquid phase pressure generated by the electric arc.

3. The test apparatus for measuring the arc characteristics of transformer low-oil bushings as described in claim 2, characterized in that, The multi-parameter detection unit further includes an arc gas generation measurement unit, which includes: A gas collection device is connected to the gas phase space of the test chamber (1) via a pipeline; The flow measurement device installed on the pipeline is used to directly measure the volume of gas generated after the electric arc discharge.

4. The test apparatus for measuring the arc characteristics of transformer bushings with low oil content as described in any one of claims 1-3, characterized in that, It also includes an arc process observation window (7) located in the middle of the test chamber (1); The multi-parameter detection unit also includes a high-speed camera device, the lens of which is aimed at the arc process observation window (7) to record the morphological evolution process of the arc bubble.

5. The test apparatus for measuring the arc characteristics of transformer bushings with low oil content as described in any one of claims 1-3, characterized in that, The electrode unit includes an upper electrode rod (112) disposed inside the upper half of the test chamber (1) and a lower electrode rod (116) disposed inside the lower half of the test chamber (1).

6. The test apparatus for measuring the arc characteristics of transformer low-oil bushings as described in claim 4, characterized in that, It also includes a gas pressure relief unit located in the middle of the test chamber (1) for releasing the high-pressure gas inside the test chamber (1).

7. The test apparatus for measuring the arc characteristics of transformer low-oil bushings as described in claim 4, characterized in that, It also includes an oil injection hole (91) located at the top of the test chamber (1), an oil drain hole (92) located at the bottom of the test chamber (1), and flanges (10) located at both ends of the test chamber (1).

8. A method for measuring the arc characteristics of a transformer bushing with low oil content, characterized in that, include: Install, arrange, and connect the measuring instruments in the multi-parameter detection unit to test the airtightness, watertightness, and normal signal transmission of the device; An arc-starting wire (114) is set between the upper electrode rod (112) and the lower electrode rod (116); the electrode unit is connected to the arc test platform; Insulating oil is injected through the oil injection hole (91), a gas space is reserved, and the initial gas phase temperature and pressure are recorded; An electric arc is generated by controlling an electric arc test platform, and data during the arc generation process is collected using a multi-parameter detection unit. After the arc discharge is completed and the temperature and pressure of the gas phase space inside the test chamber (1) are stable, the gas production is measured.

9. The measurement method for measuring the arc characteristics of a transformer low-oil bushing as described in claim 8, characterized in that, The gas production rate is obtained by direct measurement or by calculating the gas phase temperature and pressure after discharge in combination with the initial gas phase temperature and pressure recorded before the experiment.

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