Test device for simulating generation and diffusion behaviors of dissolved gas in oil and use method

Abstract

The invention discloses a test device for simulating generation and diffusion behaviors of dissolved gas in oil and a use method. The device comprises a real transformer test device, and sampling positions are arranged at different positions of the front surface and the side surface of a transformer; an insulation discharge defect gas production simulation module; the overheating defect gas production simulation module; the three-dimensional space region oil sample multi-point collection and oil dissolved gas real-time analysis module is composed of a gas collection and separation unit, a gas detection unit and an oil dissolved gas analysis and visualization device; each sampling position is connected with one group of oil sample collection and separation unit and gas detection unit through a metal oil pipe, and finally detected diffusion information of the dissolved gas in the oil at each sampling position is transmitted to the dissolved gas in the oil analysis and visualization equipment to obtain the diffusion characteristic of the fault characteristic gas in the oil. According to the invention, different types of defects are directly set in the real transformer, so that the actual fault gas production condition of the transformer can be truly and effectively simulated.

Description

Technical Field

[0001] The present invention relates to the technical field of fault diagnosis of oil-immersed transformers based on dissolved gas analysis in oil, and particularly relates to an experimental device and a usage method for simulating the generation and diffusion behavior of dissolved gas in oil. Background Art

[0002] As one of the core components of the power system, the oil-immersed transformer undertakes the tasks of voltage transformation and electric energy transmission, and its operating state is directly related to the operation and production of the entire power grid. With the increase of the operating time of the transformer, the internal oil-paper insulation composite system will deteriorate under the influence of the electric field, thermal field and mechanical field, resulting in overheating defects and insulation discharge defects. The overheating defect develops rapidly, and the internal insulation of the transformer will be quickly damaged under the action of thermal stress, even leading to the burning of the transformer; the insulation discharge defect develops diversely, and it is possible to damage all internal components of the transformer, causing extremely serious consequences and being difficult to predict. Discovering the latent faults of the transformer as early as possible and predicting their occurrence positions, development trends and types are of great significance for ensuring the operation safety of the entire power grid. The dissolved gas analysis method in oil is one of the effective means for detecting transformer faults at present. The internal faults of the transformer are a slow cumulative process from occurrence to occurrence. Before the faults occur, the concentrations of different types of fault gases will show certain regularities with the changes of time and space. Therefore, by analyzing the diffusion characteristics of the dissolved gas in the transformer oil at different positions, it is possible to predict the fault position and type, discover the overheating defect and insulation discharge defect inside the transformer in advance, and thus ensure the safe and reliable operation of the transformer.

[0003] The existing invention patent "A Method for Measuring the Diffusion Coefficient of Dissolved Gases in Partial Discharge" with the publication number CN117571553A has built a test platform consisting of an oil tank and a chromatograph. The oil tank is equipped with a set of gas-containing oil sample injection valves and sampling and detection valves, and a partial discharge gas generation module is installed in it. The diffusion coefficient of dissolved gases in the oil during partial discharge is obtained by measuring the gas concentration in the oil sample with the chromatograph. The invention patent "A Detection System for Multiple Characteristic Gases in Transformer Oil Based on Photo-Thermal Interference and Wavelength Division Multiplexing" with the publication number CN118243663A has a hardware system including a transformer oil tank with a perforated hollow anti-resonant fiber modified with an oil-gas separation membrane. The detection system includes multiple pump source lasers, multiple wavelength division multiplexers, multiple fiber amplifiers, an optical circulator, a filter, a photodetector, a computer and other devices, and can realize the simultaneous in-situ detection of dissolved multi-component fault characteristic gases in transformer oil. The invention patent "A Method and System for Gas Diffusion Analysis of a Multivariate Hybrid Oil-Paper Insulation Composite System" with the publication number CN118486379A constructs a gas diffusion model of a multivariate hybrid oil-paper insulation composite system, conducts diffusion kinetic simulation on dissolved fault characteristic gas molecules in the oil, calculates the key diffusion characteristic coefficients of the characteristic gas molecules, and obtains the diffusion characteristics of dissolved gases in the oil-paper insulation system. By searching for existing results, it can be seen that current research on the diffusion characteristics of dissolved gases in transformer oil is mostly based on a scaled-down model of an oil tank, which cannot accurately simulate the gas diffusion process in a real transformer under actual insulation discharge defects and overheating defects. Moreover, it is mostly at the theoretical level, and there is also a lack of research on the diffusion characteristics of dissolved gases in the transformer over time and space. Summary of the Invention

[0004] To overcome the above-mentioned shortcomings of the prior art, the present invention proposes an experimental device and a usage method for simulating the generation and diffusion behavior of dissolved gases in oil, abandoning the traditional method of simulating insulation discharge defects and overheating defects through a scaled-down model of an oil tank, and directly setting different types of defects in a full-scale transformer to most realistically and effectively simulate the actual gas production situation of the transformer during a fault; multiple fault sampling points are set in the three-dimensional space area of the transformer to obtain the diffusion process of different types of fault characteristic gases in the oil with spatial variation; oil sample collection devices are set at each sampling point to obtain the diffusion process of fault characteristic gases at different points in the oil over time, which is applicable to the field of gas production and fault prediction of the oil-paper insulation composite system of oil-immersed transformers.

[0005] The technical solution adopted by the present invention to solve its technical problems is: An experimental device for simulating the generation and diffusion behavior of dissolved gases in oil, comprising: True-type transformer test device, including a transformer, sampling points are set at different positions on the front and side of the transformer respectively, and each sampling point consists of a set of sampling valves and oil return valves; a fault gas generation process observation window is set at the bottom of the transformer for observing the gas generation phenomenon under internal faults of the transformer; the transformer includes a transformer pressure relief valve, a transformer low-voltage outgoing terminal, a transformer high-voltage outgoing terminal, a transformer box body, a transformer winding, a transformer tap changer, transformer insulating oil, a fault gas generation process observation window, a transformer side sampling valve and the corresponding oil return valve, a transformer front sampling valve and the corresponding oil return valve, and a metal oil pipe. The insulating discharge defect gas generation simulation module includes an insulating discharge defect and an overheating defect set inside the transformer, the dissolved gases in the oil generated, and an outer insulating paper lead connecting the tap changer and the discharge defect; an outer insulating paper lead is led out from the tap changer to the insulating oil between the middle winding and the tank wall on the front of the transformer, and a tungsten needle is connected to the end of the lead for simulating a needle-shaped electrode; the insulating discharge defect gas generation simulation module can conduct simulations of corona discharge faults in insulating oil, surface flashover discharge faults of oil-paper, and power frequency breakdown faults of oil-paper. The overheating defect gas generation simulation module includes an overheating defect set inside the transformer, the dissolved gases in the oil generated by the overheating defect, and an outer insulating paper lead connecting the tap changer and the overheating defect; an outer insulating paper lead can be led out from the tap changer to the insulating oil between the middle winding and the tank wall on the front of the transformer, and a section of resistance wire is short-circuited at the end of the outer insulating paper lead; the overheating defect gas generation simulation module can conduct simulations of low-temperature overheating defects, medium-temperature overheating defects, and high-temperature overheating defects. The three-dimensional space region oil sample multi-point collection and real-time analysis module of dissolved gases in oil includes a gas collection and separation unit, a gas detection unit, and an analysis and visualization device for dissolved gases in oil, specifically including a oil pump, an oil-gas separation chamber, a micro gas sampling pump, a fault characteristic gas inlet, a fault gas return port in the oil-gas collection and separation unit, and a six-way valve, a nitrogen cylinder, a purification filter, a nitrogen inlet, a pressure stabilizing valve, a quantitative tube, a gas chromatographic column, a semiconductor gas sensor in the gas detection unit, as well as a metal oil pipe, a polytetrafluoroethylene gas pipe, and an analysis and visualization device for dissolved gases in oil; each sampling point is connected to a set of oil sample collection and separation units and gas detection units through a metal oil pipe, and finally the diffusion information of the dissolved gases in oil at each sampling point obtained by detection is transmitted to the analysis and visualization device for dissolved gases in oil to obtain the diffusion characteristics of fault characteristic gases in oil.

[0006] Further, the total diameter of the sampling valve and the oil return valve is 8 mm, the diameter of the oil outlet and the oil return port is 4 mm, and the distance between the sampling valve and the oil return valve is 10 mm.

[0007] Furthermore, each oil pipeline is made of a 4-cm metal hollow pipe and is fixed to the sampling valve and the oil return valve through a sealing ring and a liquid-sealing bolt.

[0008] Furthermore, the method for simulating the corona discharge fault of insulating oil is as follows: Adjust the tungsten needle to maintain a certain oil gap from the transformer tank wall, gradually apply power frequency voltage to the transformer from low to high, and make it discharge to the transformer tank wall until the oil gap breaks down, with the maximum voltage not exceeding 35 kV.

[0009] Furthermore, the method for simulating the surface flashover discharge fault of oil-paper is as follows: Firmly tie the tungsten needle and the insulating block together with a polyester fiber binding band, adjust it to maintain a certain oil gap from the transformer tank wall, gradually apply power frequency voltage to the transformer from low to high, and make it discharge to the transformer tank wall until surface flashover occurs, with the maximum voltage not exceeding 35 kV.

[0010] Furthermore, the method for simulating the power frequency breakdown fault of oil-paper is as follows: Wrap 3 layers of insulating paper outside the tungsten needle and firmly tie them together with a polyester fiber binding band, adjust it to maintain a certain oil gap from the transformer tank wall, gradually apply power frequency voltage to the transformer from low to high, and make it discharge to the transformer tank wall until the oil-paper insulation breaks down, with the maximum voltage not exceeding 35 kV.

[0011] Furthermore, the method for simulating the low-temperature overheating defect is as follows: Adjust the resistance wire to maintain a certain oil gap from the transformer tank wall, heat it up to 200 K, and keep it for 30 min.

[0012] Furthermore, the method for simulating the medium-temperature overheating defect is as follows: Adjust the resistance wire to maintain a certain oil gap from the transformer tank wall, heat it up to 400 K, and keep it for 30 min.

[0013] Furthermore, the method for simulating the high-temperature overheating defect is as follows: Adjust the resistance wire to maintain a certain oil gap from the transformer tank wall, heat it up to 800 K, and keep it for 30 min.

[0014] A method for using the test device for simulating the generation and diffusion behavior of dissolved gases in oil includes the following steps: (1) Carry out the core-lifting work on the full-scale transformer test device; (2) Clean the test device and perform drying treatment under vacuum; (3) Lead out the lead wire with outer insulating paper from the tap changer; (4) Install an insulating discharge defect gas generation simulation module or an overheating defect gas generation simulation module at the end of the lead wire with outer insulating paper; (5) Close the full-scale transformer test device, and at the same time confirm that the fault gas generation position meets the expected standard; (6) Filter, degas and perform drying treatment under vacuum on the insulating oil; (7) Check whether the water content and gas content of the insulating oil meet the requirements; (8) Inject the insulating oil into the test device under vacuum; (9) Let the whole test device stand still for 24 h; (10) Conduct tests on the full-scale transformer test device under insulation discharge defects / overheating defects; (11) Start the relevant equipment in the multi-point oil sample collection in three-dimensional space area and real-time analysis module of dissolved gases in oil; (12) Take samples of dissolved gases in oil at different positions of the test equipment every 1 h, and stop sampling until 24 h; (13) Analyze the diffusion characteristics of different types of dissolved gases in oil with time and space changes in the full-scale transformer through dissolved gas analysis in oil and visualization equipment; (14) Properly handle the test insulating oil; (15) Clean the test device and conduct a drying process under vacuum.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) Having the function of simulating the actual operation condition of the transformer: The present invention abandons the traditional method of conducting fault diffusion tests through a scaled-down model of an oil tank, takes a 10 kV full-scale oil-immersed transformer as the test object, and sets insulation discharge defects and overheating defects directly in the transformer to simulate the gas generation scenario of the transformer under actual fault conditions.

[0016] (2) Having the function of simulating actual insulation discharge defects and overheating defects of the full-scale transformer: The present invention designs multi-types of actual insulation discharge defect and overheating defect modules. By simulating the actual corona discharge of insulating oil, surface flashover discharge of oil-paper, power frequency breakdown defects of oil-paper, and low-temperature, medium-temperature and high-temperature defects inside the transformer, it reveals the degradation law of the oil-paper insulation system of the transformer under the coupling of "gas-liquid" and "gas-liquid-solid" multiphase flows and "electro-thermal" defects, as well as the diffusion characteristics of dissolved gases in oil under actual fault conditions.

[0017] (3) Having the function of multi-point oil sample collection in three-dimensional space area and real-time analysis of dissolved gases in oil: The present invention designs a multi-point oil sample collection in three-dimensional space area and real-time analysis module of dissolved gases in oil. By setting multiple fault gas collection positions in the three-dimensional space area ( x , y , z direction) of the transformer tank wall, the diffusion process of different types of fault characteristic gases in oil with space changes is obtained; oil sample collection equipment is set at each collection position to obtain the diffusion process of fault characteristic gases at different points in oil with time changes. Description of the Drawings

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for the description of the embodiments will be briefly introduced below.

[0019] Figure 1 It is a side view of the overall framework of a test device for simulating the generation and diffusion behavior of dissolved gases in oil according to an embodiment of the present invention.

[0020] Figure 2 It is a front view of the overall framework of a test device for simulating the generation and diffusion behavior of dissolved gases in oil according to an embodiment of the present invention.

[0021] Figure 3 It is a flowchart of the usage method of a test device for simulating the generation and diffusion behavior of dissolved gases in oil according to an embodiment of the present invention.

[0022] In the figure: 1 - transformer pressure relief valve, 2 - transformer low-voltage outgoing terminal, 3 - transformer high-voltage outgoing terminal, 4 - transformer box body, 5 - transformer winding, 6 - transformer tap changer, 7 - transformer insulating oil, 8 - transformer side sampling valve and corresponding oil return valve, 9 - insulating discharge defect gas generation simulation module and overheating defect gas generation simulation module, 10 - dissolved gases in oil, 11 - outer insulating paper lead, 12 - observation window for the process of fault gas generation, 13 - transformer front sampling valve and corresponding oil return valve, 14 - oil pump, 15 - oil-gas separation chamber, 16 - micro gas sampling pump, 17 - fault characteristic gas inlet, 18 - fault gas return port, 19 - six-way valve, 20 - nitrogen cylinder, 21 - purification filter, 22 - nitrogen inlet, 23 - pressure stabilizing valve, 24 - metering tube, 25 - gas chromatographic column, 26 - semiconductor gas sensor, 27 - metal oil pipe, 28 - polytetrafluoroethylene gas pipe; (1)-(24) represent the labels of the sampling points, and each sampling point is composed of a group of sampling valves and oil return valves. Detailed implementation manners

[0023] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] As Figure 1 、 Figure 2 shown, an experimental device for simulating the generation and diffusion behavior of dissolved gases in oil according to an embodiment of the present invention includes: A full-scale transformer test device, including a transformer, sampling points are respectively arranged at different positions on the front and side of the transformer, and each sampling point is composed of a set of sampling valves and oil return valves; a fault gas generation process observation window 12 is arranged at the bottom of the transformer for observing the gas generation phenomenon under internal faults of the transformer. The transformer is composed of a transformer pressure relief valve 1, a transformer low-voltage outlet terminal 2, a transformer high-voltage outlet terminal 3, a transformer casing 4, a transformer winding 5, a transformer tap changer 6, transformer insulating oil 7, a fault gas generation process observation window 12, a transformer side sampling valve and the corresponding oil return valve 8, a transformer front sampling valve and the corresponding oil return valve 13, and a metal oil pipe 27; the rest of the transformer components are omitted because they are not involved in the simulation of gas generation under actual discharge faults and overheating conditions and the analysis of the diffusion characteristics of dissolved gases in oil. An insulating discharge defect gas generation simulation module and an overheating defect gas generation simulation module 9 are arranged inside the transformer to respectively simulate the dissolved gases 10 in oil generated under insulating discharge defects and overheating defects.

[0027] The selected transformer has a voltage rating of 10 kV, a capacity of 100 kVA, and dimensions of 750×380×490 mm. Sampling points are set at different positions on the front and side of the transformer. Each sampling point consists of a set of sampling valves and oil return valves. The total diameter of the sampling valve and the oil return valve is 8 mm, the diameter of the oil outlet and the oil return port is 4 mm, and the distance between the sampling valve and the oil return valve is 10 mm. The distance from the sampling valve at the sampling points numbered (1), (2), (7), (8), (13), (14), (19), and (20) to the top of the transformer tank is 110 mm. The distance from the oil return valve at the sampling points numbered (5), (6), (11), (12), (17), (18), (23), and (24) to the bottom of the transformer is 40 mm. The distance from the sampling points numbered (1), (3), and (5) to the tank wall in the opposite direction of the transformer y is 130 mm. The distance from the sampling points numbered (2), (4), and (6) to the tank wall in the y direction of the transformer is also 130 mm. The distance from the sampling points numbered (7), (9), and (11) to the tank wall in the opposite direction of the transformer x is 70 mm. The distance from the sampling points numbered (20), (22), and (24) to the tank wall in the x direction of the transformer is 70 mm. The distance from the oil return valve at the sampling points numbered (1), (2), (7), (8), (13), (14), (19), and (20) to the sampling valve at the sampling points numbered (3), (4), (9), (10), (15), (16), (21), and (22) is 150 mm. The distance from the oil return valve at the sampling points numbered (3), (4), (9), (10), (15), (16), (21), and (22) to the sampling valve at the sampling points numbered (5), (6), (11), (12), (17), (18), (23), and (24) is 150 mm. Each oil pipeline is made of a 4 cm metal hollow pipe to ensure that the mechanical strength and insulation strength meet the requirements, and is fixed to the sampling valve and the oil return valve through sealing rings and liquid sealing bolts. At the same time, quartz glass observation windows with dimensions of 710×50×10 mm are set at 125 mm and 185 mm from the bottom on the front of the transformer as the observation window 12 for the gas generation process during faults, which is used to observe the gas generation phenomenon under internal faults of the transformer.

[0028] The gas generation simulation module for insulation discharge defects consists of insulation discharge defects and overheating defects set inside the transformer, the dissolved gases 10 in the oil generated, and the external insulation paper lead 11 connecting the tap changer and the discharge defect. An external insulation paper lead 11 is led out from the tap changer to the insulating oil between the middle winding and the tank wall on the front of the transformer, and a tungsten needle is connected to the end of the lead to simulate a needle-shaped electrode. The gas generation simulation module for insulation discharge defects can simulate corona discharge faults of insulating oil, surface flashover discharge faults of oil-paper, and power frequency breakdown faults of oil-paper.

[0029] The method for simulating the corona discharge fault of insulating oil is as follows: Adjust to keep a certain oil gap between the tungsten needle and the transformer tank wall, gradually apply power frequency voltage to the transformer from low to high, and make it discharge to the transformer tank wall until the oil gap breaks down, with the maximum voltage not exceeding 35 kV.

[0030] The method for simulating the surface flashover discharge fault of oil-paper is as follows: Firmly tie the tungsten needle and the insulating block together with a polyester fiber binding band, adjust to keep a certain oil gap between it and the transformer tank wall, gradually apply power frequency voltage to the transformer from low to high, and make it discharge to the transformer tank wall until surface flashover occurs, with the maximum voltage not exceeding 35 kV.

[0031] The method for simulating the power frequency breakdown fault of oil-paper is as follows: Wrap 3 layers of insulating paper outside the tungsten needle and firmly tie them together with a polyester fiber binding band, adjust to keep a certain oil gap between it and the transformer tank wall, gradually apply power frequency voltage to the transformer from low to high, and make it discharge to the transformer tank wall until the oil-paper insulation breaks down, with the maximum voltage not exceeding 35 kV.

[0032] The overheating defect gas generation simulation module consists of an overheating defect set inside the transformer, the dissolved gas in oil 10 generated by the overheating defect, and the outer insulating paper lead 11 connecting the tap changer and the overheating defect; A lead 11 wrapped with insulating paper can be led out from the tap changer to the insulating oil between the middle winding and the tank wall on the front of the transformer, and a resistance wire is short-circuited at the end of the outer insulating paper lead 11. The overheating defect gas generation simulation module can simulate low-temperature overheating defects, medium-temperature overheating defects, and high-temperature overheating defects; The method for simulating low-temperature overheating defects is as follows: Adjust to keep a certain oil gap between the resistance wire and the transformer tank wall, heat it up to 200 K, and keep it for 30 min.

[0033] The method for simulating medium-temperature overheating defects is as follows: Adjust to keep a certain oil gap between the resistance wire and the transformer tank wall, heat it up to 400 K, and keep it for 30 min.

[0034] The method for simulating high-temperature overheating defects is as follows: Adjust to keep a certain oil gap between the resistance wire and the transformer tank wall, heat it up to 800 K, and keep it for 30 min.

[0035] Three-dimensional space region oil sample multi-point collection and in-oil dissolved gas real-time analysis module, which is composed of a gas collection and separation unit, a gas detection unit, and an in-oil dissolved gas analysis and visualization device. Specifically, it consists of oil pump 14, oil-gas separation chamber 15, micro gas sampling pump 16, fault characteristic gas inlet 17, fault gas return port 18 in the oil-gas collection and separation unit, six-way valve 19, nitrogen cylinder 20, purification filter 21, nitrogen inlet 22, pressure stabilizing valve 23, quantitative tube 24, gas chromatographic column 25, semiconductor gas sensor 26 in the gas detection unit, as well as metal oil pipes 27, polytetrafluoroethylene gas pipes 28, and an in-oil dissolved gas analysis and visualization device; each sampling point is connected to a group of oil sample collection and separation units and gas detection units through metal oil pipes 27, and finally transmits the diffusion information of the in-oil dissolved gas 10 at each sampling point obtained by detection to the in-oil dissolved gas analysis and visualization device to obtain the diffusion characteristics of the fault characteristic gas in the oil.

[0036] The sampling, detection, and transmission process of the in-oil dissolved gas at each group of sampling points are all carried out according to the following process: First, the insulating oil in the transformer is sucked into the oil-gas separation chamber 15 in the oil-gas collection and separation unit by the vacuum pressure difference method, and the fault characteristic gas is separated from the insulating oil by the vacuum degassing method, and the remaining insulating oil circulates in the transformer through the oil pump 14; after the fault characteristic gas leaves the oil-gas separation chamber 15, the micro gas separation pump in the oil-gas collection and separation unit transports the fault gas into the quantitative tube 24 of the six-way valve 19; at the same time, nitrogen from the nitrogen cylinder 20 enters the six-way valve 19 as a carrier gas through the purification filter 21, pressure stabilizing valve 23, and inlet; after the fault gas enters the chromatographic column under the push of the carrier gas, the flow rates of different types of fault gases are redistributed in the chromatographic column through adsorption, dissolution, penetration, ion exchange, etc. within a fixed time, so that different gas components flow out of the chromatographic column at different flow rates, realizing the function of the chromatographic column to batch process different types of fault gases; finally, after different flow rates and different types of fault gases enter the semiconductor gas sensor 26, the sensor converts the detected gas concentration of each fault gas into an electrical signal and inputs it to the in-oil dissolved gas analysis and visualization device to obtain the diffusion characteristics of various in-oil dissolved gases 10 in the transformer over time and space.

[0037] As Figure 3 shown, a method for using a test device for simulating the generation and diffusion behavior of in-oil dissolved gas as described above includes the following steps: (1) Carry out the core lifting work on the prototype transformer test device; (2) Clean and dry the test device under vacuum; (3) Lead out the outer insulation paper lead 11 from the tap changer; (4) Install an insulating discharge defect gas generation simulation module or an overheating defect gas generation simulation module at the end of the outer insulation paper lead 11; (5) Close the full-scale transformer test device, and at the same time confirm that the position where the fault gas is generated meets the expected standard; (6) Filter, degas and dry the insulating oil under vacuum; (7) Check whether the water content and gas content of the insulating oil meet the requirements; (8) Inject the insulating oil into the test device under vacuum; (9) Let the test device stand still for 24 h as a whole; (10) Conduct tests on the full-scale transformer test device under insulation discharge defects / overheating defects; (11) Start the relevant equipment in the multi-point oil sample collection and real-time analysis module of dissolved gases in oil in the three-dimensional space region; (12) Take samples of the dissolved gases in oil at different positions of the test equipment every 1 h until the collection stops after 24 h; (13) Analyze the diffusion characteristics of different types of dissolved gases in oil with the change of time and space in the full-scale transformer through the analysis of dissolved gases in oil and visualization equipment; (14) Properly handle the test insulating oil; (15) Clean the test device and perform the drying process under vacuum.

[0038] Based on the fact that the research on the diffusion characteristics of dissolved gases in transformer oil is mostly based on the scaled-down model of the oil tank, which cannot accurately simulate the gas diffusion process in the real transformer under actual insulation discharge defects and overheating defects, and is mostly based on the theoretical level. At the same time, there is still a lack of research on the diffusion characteristics of dissolved gases in oil with the change of time and space inside the transformer, etc. The embodiments of the present invention provide a test device for simulating the generation and diffusion behavior of dissolved gases in oil under actual insulation discharge defects and overheating defects, which can be used to study the generation characteristics of dissolved gases in oil and their diffusion characteristics with the change of time and space in the full-scale transformer under actual different insulation discharge defects and overheating defects. The embodiments of the present invention provide a solid foundation for carrying out the research on the gas generation characteristics and the diffusion kinetics characteristics of dissolved gases in oil under actual insulation discharge defects and overheating defects, which helps to improve the transformer fault prediction technology and provides technical guidance for the formulation of transformer maintenance strategies.

[0039] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A test device for simulating the generation and diffusion behavior of dissolved gas in oil, characterized in that: include: A real transformer test device includes a transformer, sampling points are arranged at different positions on the front and side of the transformer, each sampling point is composed of a group of sampling valves and oil return valves; a fault gas production process observation window is arranged at the bottom of the transformer, which is used to observe the gas production phenomenon under the internal fault of the transformer; the transformer includes a transformer pressure relief valve, a transformer low-voltage outlet terminal, a transformer high-voltage outlet terminal, a transformer box, a transformer winding, a transformer tap switch, a transformer insulating oil, a fault gas production process observation window, a transformer side sampling valve and a corresponding oil return valve, a transformer front sampling valve and a corresponding oil return valve, and a metal oil pipe; The insulation discharge defect gas generation simulation module includes the insulation discharge defect and overheating defect set inside the transformer, the generated dissolved gas in the oil, and the outer insulating paper lead connecting the tap changer and the discharge defect; an outer insulating paper lead is led out from the tap changer to the insulating oil between the middle winding and the box wall on the front of the transformer, and a tungsten needle is connected to the end of the lead to simulate the needle-shaped electrode; the insulation discharge defect gas generation simulation module can perform insulation oil corona discharge fault simulation, oil-paper surface flashover discharge fault simulation, and oil-paper power frequency breakdown fault simulation; The overheating defect gas production simulation module includes an overheating defect set inside the transformer, gas dissolved in the oil generated by the overheating defect, and an outer insulating paper lead connecting the tap switch and the overheating defect; an outer insulating paper lead can be led from the tap switch to the insulating oil between the middle winding on the front of the transformer and the box wall, and a resistance wire is short-circuited at the end of the outer insulating paper lead; the overheating defect gas production simulation module can simulate low-temperature overheating defects, medium-temperature overheating defects, and high-temperature overheating defects; The module for multi-point oil sample collection and real-time analysis of dissolved gas in oil in a three-dimensional spatial area includes a gas collection and separation unit, a gas detection unit and an analysis and visualization device for dissolved gas in oil, specifically including an oil pump, an oil-gas separation chamber, a micro gas sampling pump, a fault characteristic gas inlet, a fault gas reflux port in the oil-gas collection and separation unit and a six-way valve, a nitrogen bottle, a purification filter, a nitrogen inlet, a pressure regulating valve, a quantitative tube, a gas chromatographic column, a semiconductor gas sensitive sensor, a metal oil pipe, a polytetrafluoroethylene ventilation pipe and an analysis and visualization device for dissolved gas in oil in the gas detection unit; each sampling point is connected to a group of oil sample collection and separation units and a gas detection unit through a metal oil pipe, and finally the diffusion information of dissolved gas in oil at each sampling point obtained by detection is transmitted to the analysis and visualization device for dissolved gas in oil to obtain the diffusion characteristics of the fault characteristic gas in oil.

2. A system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The total diameter of the sampling valve and the oil return valve is 8 mm, the diameter of the oil outlet and the oil return port is 4 mm, and the distance between the sampling valve and the oil return valve is 10 mm.

3. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: Each oil pipe is a 4 cm metal hollow tube, which is fixed to the sampling valve and the oil return valve through a sealing ring and a liquid sealing bolt.

4. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The method for simulating the insulating oil corona discharge fault is as follows: a certain oil gap is maintained between the tungsten needle and the transformer box wall, and a power frequency voltage is gradually applied to the transformer from low to high, so that it discharges to the transformer box wall until the oil gap breaks down, and the maximum voltage does not exceed 35 kV.

5. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The method for simulating the oil-paper surface flashover discharge fault is as follows: the tungsten needle and the insulating block are firmly tied together by a polyester fiber binding belt, and a certain oil gap is maintained between the tungsten needle and the transformer box wall, and the power frequency voltage is gradually applied to the transformer from low to high, so that it discharges to the transformer box wall until a surface flashover occurs, and the maximum voltage does not exceed 35 kV.

6. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The method for simulating the oil-paper power frequency breakdown fault is as follows: three layers of insulating paper are wrapped around the tungsten needle and firmly tied together by a polyester fiber binding tape, and a certain oil gap is maintained between the tungsten needle and the transformer box wall, and a power frequency voltage is gradually applied to the transformer from low to high so that it discharges to the transformer box wall until the oil-paper insulation breaks down, and the maximum voltage does not exceed 35 kV.

7. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The method for simulating low-temperature overheating defects is as follows: a certain oil gap is maintained between the resistance wire and the transformer box wall, and the temperature is raised to 200 K and maintained for 30 min.

8. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The method for simulating the medium-temperature overheating defect is as follows: a certain oil gap is maintained between the resistance wire and the transformer box wall, and the temperature is raised to 400 K and maintained for 30 min.

9. The system for constructing a virtual scene for power inspection according to claim 1, characterized in that: The method for simulating high-temperature overheating defects is as follows: a certain oil gap is maintained between the resistance wire and the transformer box wall, and the temperature is raised to 800 K and maintained for 30 min.

10. A method for using the test device for simulating the generation and diffusion behavior of dissolved gas in oil according to any one of claims 1 to 9, comprising the following steps: (1) Perform core lifting work on the real transformer test device; (2) Clean the test device and dry it under vacuum; (3) Lead out the insulated paper lead wire from the tap changer; (4) Install an insulation discharge defect gas generation simulation module or an overheating defect gas generation simulation module at the end of the outer insulating paper lead; (5) Close the real transformer test device and confirm that the fault gas generation location meets the expected standards; (6) Filter, degas and dry the insulating oil under vacuum; (7) Check whether the water content and gas content of the insulating oil meet the requirements; (8) Inject insulating oil into the test device under vacuum; (9) Leave the entire test device to stand for 24 hours; (10) Conducting tests on the real transformer test device under insulation discharge defect / overheating defect; (11) Start the relevant equipment in the three-dimensional spatial area oil sample multi-point collection and oil dissolved gas real-time analysis module; (12) Sample the dissolved gas in the oil at different locations of the test equipment every 1 hour until 24 hours; (13) Analyze the diffusion characteristics of dissolved gases in different types of oil in the test device through dissolved gas analysis and visualization equipment; (14) Properly handle the test insulating oil; (15) The entire test device for simulating the generation and diffusion behavior of dissolved gas in oil is cleaned and dried under vacuum.

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