Simulation test device and test method for oil extraction pipeline of oil-immersed transformer

Abstract

The invention relates to a simulation test device and test method for oil extraction pipelines of an oil-immersed transformer, and the device comprises a thermal aging cavity, a copper electrode pair, insulation paper, an oil inlet, an oil outlet, a vacuum oil injection port, an intelligent temperature control system, a first oil extraction pipeline, a second oil extraction pipeline, a third oil extraction pipeline, an elbow, a speed-adjustable oil pump, and a three-way joint. The copper electrode pair and the insulation paper are both located in the thermal aging cavity, the insulation paper is arranged in the middle of the copper electrode pair, the oil inlet, the oil outlet and the vacuum oil injection port are all arranged outside the thermal aging cavity, the vacuum oil injection port is used for injecting insulating oil in a vacuum mode, and the intelligent temperature control system is connected with the thermal aging cavity. The oil outlet is sequentially connected with the first oil taking pipeline, the speed-adjustable oil pump, the second oil taking pipeline, the elbows, the three-way connector and the third oil taking pipeline, the third oil taking pipeline is connected with the oil outlet, circulation of insulating oil is achieved, and the number of the elbows can be changed. Compared with the prior art, the device has the advantages of being capable of simulating parameters such as the oil taking pipeline structure, the oil flow speed and the temperature of the oil-immersed transformer and analyzing the influence on the concentration of the gas dissolved in the oil and the like.

Description

Technical Field

[0001] The invention relates to the technical field of simulation testing, and in particular to a simulation testing device and a testing method for an oil-intake pipeline of an oil-immersed transformer. Background Art

[0002] With the rapid development of economy, the demand for electric energy is increasing day by day. As the key equipment for electric energy conversion and transmission, oil-immersed transformer plays a vital core role in the power system. The stable operation of the transformer is directly related to the safety, reliability and economy of the power system. The dissolved gas analysis technology in oil is the core technology in the operation status detection and abnormal early warning of oil-immersed transformers, which is mainly divided into offline laboratory detection method and online monitoring method.

[0003] The online detection device for oil-soluble gas is usually installed outside the accident oil pool of the transformer, and is several meters or even more than ten meters away from the transformer. The oil in the transformer is usually transferred to the online monitoring device through an oil extraction pipeline. The oil extraction pipeline will connect the oil inlet and outlet, enter the accident oil pool along the side wall of the transformer, be buried under the pebbles of the accident oil pool, and then be connected to the online detection device. This installation method makes the oil extraction pipeline have a longer path and more elbows, and the diameter of the oil extraction pipeline of different manufacturers is also different. In addition, the oil extraction pipeline will be partially exposed to the outdoors and partially buried in the accident oil pool, and the temperature will be different. The difference in pipeline structure and temperature may cause the dissolved gas content measured through the pipeline to deviate from the dissolved gas content in the actual transformer, and it is impossible to determine whether the measured results can truly reflect the internal state of the transformer. At present, there is no test method for the influence of factors such as oil extraction pipeline structure, oil flow rate, and temperature on the dissolved gas content in oil, and it is impossible to determine whether the detection results of the online monitoring device for dissolved gas in oil are consistent with the state of dissolved gas in the insulating oil in the transformer. Summary of the invention

[0004] The purpose of the present invention is to provide a simulation test device and test method for the oil-intake pipeline of an oil-immersed transformer, which can analyze the influence of factors such as the oil-intake pipeline structure, oil flow rate, temperature, etc. on the dissolved gas content in the oil.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A simulation test device for an oil-immersed transformer oil extraction pipeline comprises a thermal aging cavity, a copper electrode pair, insulating paper, an oil inlet, an oil outlet, a vacuum oil filling port, an intelligent temperature control system, a first oil extraction pipeline, a second oil extraction pipeline, a third oil extraction pipeline, an elbow, an adjustable speed oil pump and a three-way joint. The copper electrode pair and the insulating paper are both located inside the thermal aging cavity, and the insulating paper is arranged in the middle of the copper electrode pair to simulate the internal structure of the transformer. The oil inlet, the oil outlet and the vacuum oil filling port are all arranged outside the thermal aging cavity. The vacuum oil filling port is used for vacuum injection of insulating oil. The intelligent temperature control system is connected to the thermal aging cavity to uniformly heat the insulating oil in the thermal aging cavity. The oil outlet is sequentially connected to the first oil extraction pipeline, the adjustable speed oil pump, the second oil extraction pipeline, the elbow, the three-way joint and the third oil extraction pipeline. The third oil extraction pipeline is connected to the oil outlet to realize the circulation of insulating oil and the change of the number of elbows.

[0007] Furthermore, the adjustable speed oil pump includes an oil pump inlet, an oil pump outlet, a pump body and a frequency converter. The oil pump inlet and the oil pump outlet are respectively located on opposite sides of the pump body. The oil pump inlet is connected to a first oil intake pipeline, and the oil pump outlet is connected to a second oil intake pipeline. The pump body is connected to the frequency converter by a circuit, and is used to change the rotation speed by frequency modulation to control the flow rate of the insulating oil.

[0008] Furthermore, the intelligent temperature control system includes a heating ring, an inserted thermocouple and a control subsystem. The heating ring is located at the bottom of the thermal aging cavity and is used to uniformly heat the insulating oil. The inserted thermocouple is located at the top of the thermal aging cavity and inserted into the cavity and is used to control the temperature control accuracy. The control subsystem is arranged outside the thermal aging cavity and is used to achieve temperature control.

[0009] Furthermore, the insulating paper is fixed by a polytetrafluoroethylene fixing sleeve.

[0010] Furthermore, the three-way joint is provided with three ports for controlling whether the insulating oil at the three ports flows, wherein the first port is connected to the third oil extraction pipeline, the second port is connected to the second oil extraction pipeline, and the third port is connected to the sample oil extraction pipeline.

[0011] Furthermore, it also includes a pressure relief valve and a vacuum exhaust port both arranged outside the thermal aging chamber, the pressure relief valve is used to adjust the pressure inside the thermal aging chamber, and the vacuum exhaust port is used to connect a vacuum pump to achieve vacuum oil injection.

[0012] Furthermore, it also includes sealing rings, which are respectively arranged at the oil inlet, oil outlet, pressure relief valve, vacuum oil filling port and vacuum exhaust port.

[0013] Furthermore, the elbow is a right-angle elbow, which is arranged on the first oil extraction pipeline or the second oil extraction pipeline or the third oil extraction pipeline to realize a multi-section pipeline combination.

[0014] Furthermore, the first oil extraction pipeline, the second oil extraction pipeline, and the third oil extraction pipeline are all made of polytetrafluoroethylene tubes or stainless steel tubes, and are all wrapped with a thermal insulation layer on the outside.

[0015] The present invention also provides a testing method of the simulation testing device for the oil-intake pipeline of the oil-immersed transformer described above, comprising the following steps:

[0016] Injecting pretreated insulating oil into the thermal aging cavity through the vacuum oil filling port and the vacuum exhaust port;

[0017] The insulating oil is subjected to heat aging treatment at a set heating temperature and a set duration by means of an intelligent temperature control system, so that the insulating paper and the insulating oil generate fault gas, wherein the fault gas includes methane, ethane, ethylene, hydrogen, carbon monoxide and carbon dioxide, and then the insulating oil containing high concentration of acetylene prepared in advance is quantitatively injected into the insulating oil after heat aging, so that the acetylene fault gas is uniformly dissolved in the insulating oil;

[0018] Open the oil inlet, the oil outlet, the adjustable speed oil pump, and the first port and the second port of the three-way joint, so that the insulating oil containing the faulty gas passes through the oil outlet, the first oil extraction pipeline, the adjustable speed oil pump, the second oil extraction pipeline, the three-way joint, the third oil extraction pipeline and the oil inlet in sequence to realize circulation;

[0019] Close the oil inlet, the oil outlet, the adjustable speed oil pump, and the first and second ports of the three-way joint, and open the third port of the three-way joint for sampling;

[0020] Repeat the above steps multiple times to perform multiple groups of experimental simulations, wherein each group of experimental simulations includes multiple fault gases and multiple samplings;

[0021] According to the multiple sampling samples of each group of experimental simulation, the fault gas concentration of each group of experimental simulation is obtained by gas chromatography, and the fault gas concentration of each group is fitted to obtain the fault gas concentration change trend diagram of each group;

[0022] According to the fault gas concentrations simulated by two adjacent experimental groups, the fault gas change rate of the two adjacent groups is calculated. The calculation formula is:

[0023] a=(n1-n2) / n1*100%

[0024] In the formula, a is the fault gas change rate, n1 and n2 are the fault gas concentrations of two adjacent groups;

[0025] According to the change rates of the fault gases in the two adjacent groups, the group with abnormal concentration change is determined to complete the detection process.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention simulates the internal structure of the transformer by using a copper electrode pair and insulating paper, adopts an intelligent temperature control system to uniformly heat the insulating oil in the cavity, simulates the thermal aging process by temperature control to generate fault gas during the test, and adopts an adjustable speed oil pump, oil inlet and outlet, and oil extraction pipeline to realize the circulation of insulating oil, so that the dissolved gas in the oil of the simulated test device truly reflects the state of the transformer.

[0028] (2) In the intelligent temperature control system of the present invention, the heating ring heats the insulating oil in the thermal aging chamber uniformly, the inserted thermocouple controls the temperature error within a smaller range, and the control subsystem controls the heating range of the temperature, providing different temperature control simulation environments for the insulating oil in the thermal aging chamber, thereby achieving high-precision, stable and uniform heating of the insulating oil and insulating paper in the thermal aging chamber.

[0029] (3) The adjustable speed oil pump of the present invention changes the rotation speed of the pump body by frequency modulation of the frequency converter, thereby controlling the flow rate of the insulating oil under different experimental conditions, and then realizing the circulation of the insulating oil by connecting the various oil extraction pipelines and the inlet and outlet oil ports.

[0030] (4) The present invention can control parameters such as the length, diameter, number of elbows, oil flow rate, and temperature of the oil extraction pipeline, and realize the test and analysis of the influence of various parameters of the oil extraction pipeline on the oil-soluble gas content, providing a basis for the structural design and installation of the oil extraction pipeline of the oil-soluble gas online monitoring device, and is accurate, efficient, and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 It is a schematic diagram of the heat aging chamber and its internal and external structures of the present invention;

[0033] Figure 3 It is a fitting diagram of the influence rate change trend of methane gas of the present invention;

[0034] Figure 4 It is a fitting diagram of the influence rate variation trend of ethylene gas of the present invention;

[0035] Figure 5 It is a fitting diagram of the influence rate change trend of ethane gas of the present invention;

[0036] Figure 6 It is a fitting diagram of the influence rate change trend of acetylene gas of the present invention;

[0037] Figure 7It is a fitting diagram of the influence rate change trend of carbon monoxide gas of the present invention;

[0038] Figure 8 It is a fitting diagram of the influence rate change trend of the carbon dioxide gas of the present invention;

[0039] Fig. 9 It is a fitting diagram of the influence rate change trend of hydrogen gas of the present invention;

[0040] 1: thermal aging chamber; 2: oil inlet; 3: oil outlet; 4: elbow; 5: first oil extraction pipeline; 6: three-way connector, 6-1: first port, 6-2: second port, 6-3: third port; 7: pump body; 8: oil pump inlet; 9: oil pump outlet; 10: frequency converter; 11: second oil extraction pipeline; 12: third oil extraction pipeline; 13: copper electrode pair; 14: insulating paper; 15: heating ring; 16: inserted thermocouple; 17: control subsystem; 18: pressure relief valve; 19: vacuum oil filling port; 20: vacuum exhaust port. DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0042] Example 1

[0043] This embodiment provides a simulation test device for an oil-immersed transformer oil intake pipeline. Figure 1 As shown, the device includes: a thermal aging chamber 1, an oil inlet 2, an oil outlet 3, an elbow 4, a first oil extraction pipeline 5, a three-way joint 6, an adjustable speed oil pump, an intelligent temperature control system, a second oil extraction pipeline 11, a third oil extraction pipeline 12, a copper electrode pair 13, an insulating paper 14, a pressure relief valve 18, a vacuum oil filling port 19 and a vacuum exhaust port 20.

[0044] The thermal aging chamber 1 uses an intelligent temperature control system to control the temperature in the range of 75 to 120°C, which meets the thermal aging conditions and can prepare sample insulating oils containing seven fault characteristic gases. The fault gases include acetylene (C2H2), methane (CH4), ethane (C2H6), ethylene (C2H4), hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2), with a concentration range of 20-300μL / L. The chamber is made of high temperature resistant, high pressure resistant and corrosion resistant stainless steel materials to ensure that the chamber will not affect the experiment.

[0045] like Figure 2As shown, the copper electrode pair 13 and the insulating paper 14 are fixed inside the heat aging chamber 1 by a polytetrafluoroethylene fixing sleeve to simulate the internal structure of the transformer. During the heat aging process, the insulating paper 14 and the insulating oil will produce fault gas to simulate the occurrence of the fault; the fixing sleeve is selected from polytetrafluoroethylene materials with high temperature resistance and corrosion resistance to ensure the stability of the material during the experiment. The upper cover of the cavity has an oil inlet 2, an oil outlet 3, a 0.2MPa pressure relief valve 18, a vacuum oil filling port 19 and a vacuum exhaust port 20, and is equipped with a sealing ring to enhance the sealing effect. The oil inlet 2 is connected to the first oil extraction pipeline 5, the oil outlet 3 is connected to the third oil extraction pipeline 12, and the oil inlet and outlet are equipped with a pressure gauge and a thermometer, which can monitor the physical parameters of the oil body in real time to ensure the effective operation of the circulation system. The 0.2MPa pressure relief valve 18 can realize the pressure adjustment in the cavity to prevent the pressure from being too high. The vacuum oil filling port 19 is used to connect the vacuum oil filling machine, and the vacuum exhaust port 20 is connected to the vacuum pump to realize the vacuum oil filling function.

[0046] The intelligent temperature control system consists of a heating ring 15, an inserted thermocouple 16 and a control subsystem 17. The heating ring 15 is located at the bottom of the thermal aging chamber 1, and can realize uniform heating of the insulating oil in the chamber. The inserted thermocouple 16 is located at the top of the thermal aging chamber 1 and inserted into the chamber, and can control the temperature control accuracy within ±0.5°C. The control subsystem 17 is located outside the thermal aging chamber 1, and can realize a temperature control range of 10-200°C, which can realize high-precision, stable and uniform heating of the insulating oil and insulating paper in the thermal aging chamber 1.

[0047] The adjustable speed oil pump is composed of an oil pump inlet 8, an oil pump outlet 9, a pump body 7 and a frequency converter 10. The frequency converter 10 is connected to the pump body 7 by a circuit, and the speed of the oil pump can be changed by frequency modulation to control the oil flow rate. The oil pump inlet 8 is connected to the first oil extraction pipeline 5, and the oil pump outlet 9 is connected to the second oil extraction pipeline 11. The circulation of insulating oil can be achieved by connecting the oil inlet and outlet on the thermal aging chamber 1, the adjustable speed oil pump and multiple oil extraction pipelines. In the experiment, the speed range of the adjustable speed oil pump is 0-1800rpm, and the corresponding insulating oil flow rate control range in the oil extraction pipeline is 0-4.5L / min, which can realize the control of different oil flow rates.

[0048] The three-way connector 6 has three controllable valves, wherein the first port 6-1 is connected to the third oil extraction pipeline 12, the second port 6-2 is connected to the second oil extraction pipeline 11, and the third port 6-3 is connected to the sample oil extraction pipeline, and the opening and closing are controlled by the valve knob. The three controllable valves can control whether the liquid in the three channels flows. The valves of the first port 6-1 and the second port 6-2 control whether the liquid in the system circulates, and the valve of the third port 6-3 is only opened when sampling, and is used for short-term sampling.

[0049] The first oil extraction pipeline 5, the second oil extraction pipeline 11, and the third oil extraction pipeline 12 are made of polytetrafluoroethylene (PTFE) tubes or 316L stainless steel tubes to ensure that the pipeline itself will not have adverse effects on the insulating oil under the experimental temperature conditions, and to ensure the long-term operation stability of the system. The diameter range is 4-8mm, and the outer part of the pipeline is wrapped with an insulation layer to control the oil temperature in the entire system. In order to ensure smooth connection of the pipelines, elbows 4 can be set on the first oil extraction pipeline 5, the second oil extraction pipeline 11, and the third oil extraction pipeline 12 to connect the pipelines. The elbow 4 is a right-angle elbow, and the total length of the oil extraction pipeline is 6-20m by matching multiple sections of pipelines with elbows. The number of elbows can be changed by different combinations of segmented pipelines of different lengths. The number of elbows varies in the range of 3-6, which can realize flexible adjustment of the length, number of elbows and diameter of the oil extraction pipeline.

[0050] During the connection between the above components, special attention was paid to the sealing of each interface to ensure that there was no gas leakage during the experiment and the accuracy of the data was guaranteed. Finally, a simulation test device that truly reflects the status of the transformer was obtained.

[0051] Example 2

[0052] This embodiment provides a test method for the simulation test device of the oil-immersed transformer oil intake pipeline according to Embodiment 1, and the method comprises the following steps:

[0053] Step 1: 3.5L of pretreated insulating oil is injected into the heat aging chamber 1 through the vacuum oil injection port 19 and the vacuum exhaust port 20 by vacuum oil injection. Under the environmental condition where the temperature is set to 120°C, the pretreated insulating oil is subjected to heat aging treatment for 72 hours to generate fault gases methane (CH4), ethane (C2H6), ethylene (C2H4), hydrogen (H2), carbon monoxide (CO) and carbon dioxide (CO2).

[0054] Step 2: First prepare insulating oil containing high concentration of acetylene (C2H2), and then quantitatively inject 20mL of high concentration acetylene insulating oil into the insulating oil after heat aging through precise measurement, and allow it to stabilize for 7 days to evenly dissolve the acetylene fault gas in the insulating oil.

[0055] Step 3: Install the oil extraction pipeline of corresponding length, elbow and pipeline diameter as required. The cover above the thermal aging chamber 1 has an oil outlet 2 and an oil inlet 3. Pipelines are led out from the two ports. The oil outlet 2 is connected to the oil extraction pipeline 5 with a length of 0.5m, and the other end is connected to the oil pump inlet 8 of the oil pump. The distance of the first oil extraction pipeline 5 should not be too long to prevent damage to the oil pump. The power supply end of the pump body 7 is connected to the frequency converter 10 to realize the speed control of the oil pump.

[0056] Furthermore, the oil pump outlet 9 on the other side of the pump body 7 is connected to the second oil extraction pipeline 11 and the third oil extraction pipeline 12 of different lengths and different numbers of elbows 4 required by the test. One side of the second oil extraction pipeline 11 is connected to the oil pump outlet 9, and the other side is connected to the second port 6-2 of the three-way joint 6. One end of the third oil extraction pipeline 12 is connected to the first port 6-1 of the three-way joint 6, and the other end of the third oil extraction pipeline 12 is connected to the oil inlet 3 of the thermal aging chamber 1. The third port 6-3 of the three-way joint 6 is used for sampling. Ensure that the connector is tightly connected to the oil extraction pipeline, and the pump body 7, the oil inlet and outlet, and the three-way valves should be in a closed state.

[0057] Step 4: Turn on the intelligent temperature control system, control to the required temperature, open the oil outlet 2 and the oil inlet 3 of the thermal aging chamber 1, and open the first port 6-1 and the second port 6-2 of the three-way connector 6.

[0058] Step 5: Turn on the adjustable speed oil pump, change the flow rate of the insulating oil in the oil intake pipeline through the inverter 10 knob as required, and run the system for 15 minutes to wait for it to diffuse evenly inside.

[0059] Step 6: Before sampling, check that all connectors are tightly connected to the oil extraction pipeline, and that the speed-adjustable oil pump, oil outlet 2, oil inlet 3, and valves of the three-way connector 6 are all in a closed state. Use a 100mL needle syringe to tightly connect the sample oil extraction pipeline, open the third port 6-3 of the three-way connector 6, and quantitatively sample 40mL. Each set of experimental conditions should be sampled 3 times.

[0060] Step 7: First close the third port 6-3 of the three-way sampling connector 6, then close the adjustable speed oil pump, and then close the oil outlet 2, oil inlet 3 of the thermal aging chamber 1 and the first port 6-1 and the second port 6-2 of the three-way connector 6.

[0061] Step 8: Obtain the characteristic gas concentration in each experimental group through gas chromatography. The data used for analysis should be the average value of the characteristic gas concentration obtained by three samplings. Fit each characteristic gas concentration separately to obtain the concentration change trend graph of the seven characteristic gases.

[0062] Step 9: Calculate the characteristic gas change rate a (unit: %) of each adjacent group based on the characteristic gas concentrations n1 and n2 (unit: μL / L) of two adjacent groups of experiments. The specific formula is as follows:

[0063] a=(n1-n2) / n1*100%

[0064] The judgment of abnormal values ​​refers to the relative deviation of the difference between two experimental measurement values ​​proposed in GB / T 17623-2017, that is, the difference between the measurement values ​​of adjacent groups is less than 15% when the concentration of dissolved gas in oil is greater than 10uL / L; less than 30% when it is less than or equal to 10uL / L. The gas change rate of each adjacent group is calculated based on the experimental data of each group, and the group with abnormal gas concentration change is judged to verify the influence of various factors on the dissolved gas content in oil.

[0065] Based on the above-mentioned device and method, multiple groups of different pipeline lengths were used to conduct oil transportation experiments when other conditions were constant, and oil samples were extracted for analysis to explore the influence of pipeline length on dissolved gas content.

[0066] That is, under the experimental conditions of a pipeline diameter of 6 mm, 3 elbows 4, a flow rate in the oil pipeline of 300 mL / min, and a set temperature of 40°C (hereinafter referred to as Group A); under the experimental conditions of a pipeline diameter of 6 mm, 3 elbows 4, a flow rate in the oil pipeline of 600 mL / min, and a set temperature of 40°C (hereinafter referred to as Group B); under the experimental conditions of a pipeline diameter of 6 mm, 3 elbows 4, a flow rate in the oil pipeline of 1000 mL / min, and a set temperature of 40°C (hereinafter referred to as Group C); under the experimental conditions of a pipeline diameter of 6 mm, 4 elbows 4, a flow rate in the oil pipeline of 300 mL / min, and a set temperature of 40°C (hereinafter referred to as Group D), the pipeline length was changed to 6 m, 10 m, 15 m, and 20 m, respectively, the dissolved gas content in the oil was measured, the dissolved gas content in the oil was fitted, and the gas influence rate was calculated.

[0067] The fitting diagrams of the influence rate change trends of each gas are shown in Figure 2. Figure 3 (methane gas), Figure 4 (ethylene gas), Figure 5 (ethane gas), Figure 6 (Acetylene gas), Figure 7 (Carbon monoxide gas), Figure 8 (Carbon dioxide gas), Fig. 9 (hydrogen gas). The concentration change rates of each gas in two adjacent groups in each parallel experiment are shown in Table 1, Table 2, Table 3, and Table 4.

[0068] Table 1 Gas content change rate of each adjacent group in parallel group A

[0069]

[0070] Table 2 Change rate of gas content in adjacent groups in parallel group B

[0071]

[0072] Table 3 Gas content change rate of each adjacent group in parallel group C

[0073]

[0074] Table 4 Gas content change rate of each adjacent group in parallel group D

[0075]

[0076]

[0077] The experimental calculation results show that the normal gas change group accounts for 96.83% of the total number of groups. The gas changes in each group are within the normal error fluctuation range. Combined with the trend of the fitting curve, it can be explained that the change in the length of the oil extraction pipeline will not affect the dissolved gas content, verifying the rationality of the oil extraction pipeline.

[0078] In summary, the simulation test device and test method for the oil-intake pipeline of an oil-immersed transformer proposed in the embodiment of the present invention can control parameters such as the length, diameter, number of elbows, oil flow rate, and temperature of the oil-intake pipeline, and realize the test analysis of the influence of various parameters of the oil-intake pipeline on the oil-soluble gas content, providing a basis for the structural design and installation of the oil-intake pipeline of the oil-soluble gas online monitoring device.

[0079] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0080] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A simulation test device for an oil-immersed transformer oil pipeline, characterized in that: The invention comprises a thermal aging chamber (1), a copper electrode pair (13), insulating paper (14), an oil inlet (2), an oil outlet (3), a vacuum oil filling port (19), an intelligent temperature control system, a first oil extraction pipeline (5), a second oil extraction pipeline (11), a third oil extraction pipeline (12), an elbow (4), an adjustable speed oil pump and a three-way joint (6), wherein the copper electrode pair (13) and the insulating paper (14) are both located inside the thermal aging chamber (1), and the insulating paper (14) is arranged in the middle of the copper electrode pair (13) to simulate the internal structure of the transformer, and the oil inlet (2), the oil outlet (3) and the vacuum oil filling port (19) are connected to the thermal aging chamber (1). The heat aging chamber (1) and the vacuum oil injection port (19) are both arranged outside the heat aging chamber (1); the vacuum oil injection port (19) is used for vacuum injection of insulating oil; the intelligent temperature control system is connected to the heat aging chamber (1) and is used for uniformly heating the insulating oil in the heat aging chamber (1); the oil outlet (3) is connected to the first oil extraction pipeline (5), the adjustable speed oil pump, the second oil extraction pipeline (11) and the third oil extraction pipeline (12) in sequence; the third oil extraction pipeline (12) is connected to the oil outlet (3) to realize the circulation of insulating oil and the change of the number of elbows (4).

2. The simulation test device for the oil-intake pipeline of an oil-immersed transformer according to claim 1 is characterized in that: The adjustable speed oil pump comprises an oil pump inlet (8), an oil pump outlet (9), a pump body (7) and a frequency converter (10); the oil pump inlet (8) and the oil pump outlet (9) are respectively located on opposite sides of the pump body (7); the oil pump inlet (8) is connected to a first oil extraction pipeline (5); the oil pump outlet (9) is connected to a second oil extraction pipeline (11); the pump body (7) and the frequency converter (10) are connected by circuitry and are used to change the rotation speed by frequency modulation to control the flow rate of insulating oil.

3. The simulation test device for the oil-intake pipeline of an oil-immersed transformer according to claim 1 is characterized in that: The intelligent temperature control system comprises a heating ring (15), an inserted thermocouple (16) and a control subsystem (17); the heating ring (15) is located at the bottom of the thermal aging chamber (1) and is used to uniformly heat the insulating oil; the inserted thermocouple (16) is located at the top of the thermal aging chamber (1) and is inserted into the chamber and is used to control the temperature control accuracy; the control subsystem (17) is arranged outside the thermal aging chamber (1) and is used to achieve temperature control.

4. The simulation test device for oil-intake pipeline of oil-immersed transformer according to claim 1 is characterized in that: The insulating paper (14) is fixed by a polytetrafluoroethylene fixing sleeve.

5. The simulation test device for oil-intake pipeline of oil-immersed transformer according to claim 1 is characterized in that: The three-way joint (6) is provided with three ports for controlling whether insulating oil flows at the three ports, wherein the first port (6-1) is connected to the third oil extraction pipeline (12), the second port (6-2) is connected to the second oil extraction pipeline (11), and the third port (6-3) is connected to the sample oil extraction pipeline.

6. The simulation test device for oil-intake pipeline of oil-immersed transformer according to claim 1, characterized in that: It also includes a pressure relief valve (18) and a vacuum exhaust port (20) both of which are arranged outside the thermal aging chamber (1); the pressure relief valve (18) is used to adjust the pressure inside the thermal aging chamber (1); and the vacuum exhaust port (20) is used to connect to a vacuum pump to achieve vacuum oil injection.

7. The simulation test device for oil-intake pipeline of oil-immersed transformer according to claim 6, characterized in that: It also includes sealing rings, which are respectively arranged at the oil inlet (2), the oil outlet (3), the pressure relief valve (18), the vacuum oil filling port (19) and the vacuum exhaust port (20).

8. The simulation test device for oil-intake pipeline of oil-immersed transformer according to claim 1, characterized in that: The elbow (4) is a right-angle elbow, which is arranged on the first oil extraction pipeline (5) or the second oil extraction pipeline (11) or the third oil extraction pipeline (12) and is used to realize a multi-section pipeline combination.

9. The simulation test device for oil-intake pipeline of oil-immersed transformer according to claim 1, characterized in that: The first oil extraction pipeline (5), the second oil extraction pipeline (11) and the third oil extraction pipeline (12) are all made of polytetrafluoroethylene tubes or stainless steel tubes, and are all wrapped with a thermal insulation layer on the outside.

10. A testing method for a simulation testing device for an oil-immersed transformer oil intake pipeline according to any one of claims 1 to 7 or 9, characterized in that: The following steps are involved: Injecting pretreated insulating oil into the thermal aging cavity (1) through the vacuum oil injection port (19) and the vacuum exhaust port (20); The insulating oil is subjected to a heat aging treatment at a set heating temperature and a set duration by means of an intelligent temperature control system, so that the insulating paper (14) and the insulating oil generate fault gas, wherein the fault gas includes methane, ethane, ethylene, hydrogen, carbon monoxide and carbon dioxide, and then the insulating oil containing a high concentration of acetylene prepared in advance is quantitatively injected into the insulating oil after heat aging, so that the acetylene fault gas is uniformly dissolved in the insulating oil; The oil inlet (2), the oil outlet (3), the adjustable speed oil pump, and the first port (6-1) and the second port (6-2) of the three-way joint (6) are opened to allow the insulating oil containing the faulty gas to circulate in sequence through the oil outlet (3), the first oil extraction pipeline (5), the adjustable speed oil pump, the second oil extraction pipeline (11), the three-way joint (6), the third oil extraction pipeline (12), and the oil inlet (2); The oil inlet (2), the oil outlet (3), the adjustable speed oil pump, and the first port (6-1) and the second port (6-2) of the three-way connector (6) are closed, and the third port (6-2) of the three-way connector (6) is opened for sampling; Repeat the above steps multiple times to perform multiple groups of experimental simulations, wherein each group of experimental simulations includes multiple fault gases and multiple samplings; According to the multiple sampling samples of each group of experimental simulation, the fault gas concentration of each group of experimental simulation is obtained by gas chromatography, and the fault gas concentration of each group is fitted to obtain the fault gas concentration change trend diagram of each group; According to the fault gas concentrations simulated by two adjacent experimental groups, the fault gas change rate of the two adjacent groups is calculated. The calculation formula is: a=(n1-n2) / n1*100% In the formula, a is the fault gas change rate, n1 and n2 are the fault gas concentrations of two adjacent groups; According to the change rates of the fault gases in the two adjacent groups, the group with abnormal concentration change is determined to complete the detection process.

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