Experimental device for simulating the degradation mechanism of metal contacts of on-load tap changer

Abstract

The present invention discloses a simulated experimental device for the degradation mechanism of metal contacts of an on-load tap changer, comprising: an AC power input terminal, a booster, a test transformer, a current limiting protection resistor, a capacitor voltage divider and a test oil flow circuit electrically connected in sequence, wherein the AC power input terminal is externally connected to AC power; the test oil flow circuit comprises a sampling tube, a high-voltage test oil circuit unit, a pressure release unit, a flow control valve and a vacuum oil pump connected in sequence through a pipeline, wherein the sampling tube is connected to the vacuum oil pump through a pipeline, and the capacitor voltage divider is electrically connected to the high-voltage test oil circuit unit. The present invention can determine the influencing factors of the degradation of the metal material of the contact when simulating and analyzing different discharge types and different voltage levels in the laboratory, which is conducive to diagnosing the damage of the metal contacts of the on-load tap changer.

Description

Technical Field

[0001] The invention relates to the field of testing of an arc-extinguishing combined on-load tap changer in oil, and in particular to a simulation experimental device for a degradation mechanism of a metal contact of an on-load tap changer. Background Art

[0002] On-load tap changer is an important component of large power transformers. It balances the voltage by adjusting the internal contact position of the tap changer, avoiding large-scale voltage fluctuations at the user end and enhancing the stability and reliability of the power grid.

[0003] At present, there are many types of on-load tap changers, which can be divided into combined and composite types according to whether the switching switch has an independent oil chamber. This scheme is aimed at the research of the switching switch of the combined oil-in-arc extinguishing on-load tap changer in the transformer. Specifically, when the transformer performs the voltage regulation operation, the voltage selector of the on-load tap changer is pre-moved to the corresponding lower voltage contact, and then the load current is transferred through the switching switch. In this process, the current will be transferred to the circuit on the other side to complete the corresponding voltage regulation. During the transfer of load current, an arc will be generated. Under the action of the arc, the metal on the surface of the metal contact of the switching switch will be detached, or suspended in the surrounding insulating medium in the form of metal particles, or dissolved in the insulating oil in the form of ions. In the presence of the arc, some metal particles react with impurities in the insulating oil or some aging acid products of the insulating oil, and finally generate metal ions.

[0004] The metal particles or metal ions inside the oil-immersed transformer will cause great damage to the internal insulation. Under high temperature and strong electromagnetic environment, the presence of metal ions will accelerate the aging of the transformer, and the acidic substances in the transformer oil aging products will in turn further corrode the surface of the metal contacts. For the on-load tap changer, the corrosion of the contacts will increase the contact resistance of the surface and increase the relative conductive distance. In some extreme cases, the increase in the conductive distance will cause the current to be interrupted prematurely when the switch cuts off the current, causing internal faults of the transformer. Summary of the invention

[0005] In order to solve at least one of the above technical problems, the main purpose of the present invention is to provide an experimental device for simulating the degradation mechanism of metal contacts of an on-load tap changer.

[0006] To achieve the above-mentioned purpose, a technical solution adopted by the present invention is: to provide an experimental device for simulating the degradation mechanism of metal contacts of an on-load tap changer, comprising: an AC power supply input end, a booster, a test transformer, a current limiting protection resistor, a capacitive voltage divider and a test oil flow circuit electrically connected in sequence, wherein the AC power supply input end is externally connected to AC power; the test oil flow circuit comprises a sampling tube, a high-pressure test oil circuit unit, a pressure release unit, a flow control valve and a vacuum oil pump connected in sequence through pipelines, wherein the sampling tube is connected to the vacuum oil pump through a pipeline, and the capacitive voltage divider is electrically connected to the high-pressure test oil circuit unit.

[0007] Among them, the high-pressure test oil circuit unit includes an oil circuit fixed base 28 with a pipeline structure, and a high-pressure connector and a low-pressure connector arranged on the oil circuit fixed base 28 and separated from each other. The pipeline structure is formed with two connection ports. The high-pressure connector includes a high-pressure electrode connecting conductor partially extending into the pipeline structure, and the end of the high-pressure electrode connecting conductor located outside the pipeline structure is connected to a high-pressure wire connector, and the end of the high-pressure electrode connecting conductor located inside the pipeline structure is connected to a high-pressure electrode; the low-pressure connector includes a low-pressure electrode connecting conductor partially extending into the pipeline, and the end of the low-pressure electrode connecting conductor located outside the pipeline is connected to a low-pressure wire connector, and the end of the low-pressure electrode connecting conductor located inside the pipeline structure is connected to a low-pressure electrode or a grounding electrode. The low-pressure electrode and the high-pressure electrode are separated from each other and arranged opposite to each other.

[0008] Wherein, the portion of the high-voltage electrode connecting conductor located outside the pipeline structure is provided with a high-voltage area conductor insulating sleeve, and a high-voltage area limiting bolt is provided on the high-voltage electrode connecting conductor and used to fasten the high-voltage area conductor insulating sleeve;

[0009] The portion of the low-voltage electrode connecting conductor located outside the pipeline structure is sleeved with a low-voltage area conductor insulating sleeve, and a low-voltage area limiting bolt is arranged on the low-voltage electrode connecting conductor and used to fasten the low-voltage area conductor insulating sleeve.

[0010] Wherein, the material of the pipeline structure is resin material.

[0011] It also includes a temperature regulating and metering unit mounted outside the pipeline between the pressure release unit and the flow control valve, the temperature regulating and metering unit includes an electronic thermometer controller arranged on the outside of the pipeline, and a water bath heating unit and a refrigeration unit mounted on the outside of the pipeline, the electronic thermometer controller is electrically connected to the water bath heating unit and the refrigeration unit respectively.

[0012] Wherein, the water bath heating unit is a water tank with a heating rod, and the refrigeration unit is a heat dissipation ring.

[0013] It also includes a flow rate metering unit which is sleeved outside the pipeline between the pressure release unit and the flow control valve, and the flow rate metering unit is an ultrasonic flow meter.

[0014] Wherein, the pressure release unit includes an exhaust valve and a three-way adapter having one end connected to the exhaust valve, and the remaining two ends of the three-way adapter are respectively connected to the high-pressure test oil circuit unit and the flow control valve through pipelines.

[0015] Wherein, the sampling tube is a three-way structure, and the two ends of the sampling tube are connected to the high-pressure test oil circuit unit and the vacuum oil pump through pipelines respectively, and the remaining end is the sampling end.

[0016] Wherein, the pipeline is a corrugated pipe.

[0017] The technical solution of the present invention comprises an AC power input end, a booster, a test transformer, a current limiting protection resistor, a capacitive voltage divider and a test oil flow circuit, wherein the test oil flow circuit comprises a sampling tube connected by a pipeline, a high-pressure test oil circuit unit, a pressure release unit, a flow control valve and a vacuum oil pump, and a temperature regulating metering unit and a flow rate metering unit outside the pipeline between the pressure release unit and the flow control valve. The experimental data of the degradation of metal contacts can be determined by simulating different discharge types (including arc breakdown and corona discharge) and different voltage levels in the laboratory. By comparing the experimental data, the main factors affecting the degradation of the metal contacts can be analyzed, which is conducive to diagnosing the damage of the metal contacts of the on-load tap changer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0019] Figure 1 It is a schematic block diagram of a module of an experimental device for simulating the degradation mechanism of metal contacts of an on-load tap changer according to an embodiment of the present invention;

[0020] Figure 2 A block diagram of a test oil flow circuit according to an embodiment of the present invention;

[0021] Figure 3 This is a module block diagram of a high-pressure test oil circuit unit according to an embodiment of the present invention;

[0022] Figure 4 This is a module block diagram of a temperature adjustment and metering unit according to an embodiment of the present invention;

[0023] Figure 5 The figure is a module block diagram of a pressure release unit according to an embodiment of the present invention.

[0024] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] Different from the problem in the prior art that metal ions or metal ions in oil-immersed transformers will corrode the switching performance of the internal on-load tap changer metal contacts and even cause transformer failure, the present invention provides an on-load tap changer metal contact degradation mechanism simulation experimental device, which aims to analyze the effects of corona discharge and arc breakdown on metal contacts and the generation of metal ions in insulating oil. Please refer to the following embodiments for the specific structure of the on-load tap changer metal contact degradation mechanism simulation experimental device.

[0028] Please refer to Figure 1 and Figure 2 , Figure 1 It is a schematic block diagram of a module of an experimental device for simulating the degradation mechanism of metal contacts of an on-load tap changer according to an embodiment of the present invention; Figure 2The module block diagram of the test oil flow circuit of an embodiment of the present invention. In the embodiment of the present invention, the on-load tap changer metal contact degradation mechanism simulation experimental device comprises: an AC power input terminal 1, a booster 2, a test transformer 3, a current limiting protection resistor 4, a capacitive voltage divider 5 and a test oil flow circuit 6 electrically connected in sequence, wherein the AC power input terminal 1 is externally connected to AC power; the test oil flow circuit 6 comprises a sampling tube 9, a high-voltage test oil circuit unit 8, a pressure release unit 7, a flow control valve 12 and a vacuum oil pump 13 connected in sequence through pipelines, wherein the sampling tube 9 is connected to the vacuum oil pump 13 through a pipeline, and the capacitive voltage divider 5 is electrically connected to the high-voltage test oil circuit unit 8.

[0029] In this embodiment, the AC power input terminal 1 can be connected to the mains, and the booster 2 can boost the mains. The current limiting protection resistor 4 protects the test transformer 3. The capacitive voltage divider 5 can be used to test the different breakdown voltages of the test oil flow circuit 6. The test oil flow circuit 6 is used to test the metal ions in the oil, and then determine the effects of corona discharge, arc breakdown and voltage level on the degradation of metal contacts. Specifically, the high-voltage test oil circuit unit 8 can perform a pressurized test of metal ions in the oil. In the corona discharge and breakdown experiments, the pressure release unit 7 can exhaust the oil flow circuit after the discharge experiment has been maintained for a certain period of time to prevent excessive gas from being generated inside, which will cause greater pressure on the oil flow pipeline, especially the resin test area. The sampling tube 9 can obtain the oil sample for the test. The flow control valve 12 and the vacuum oil pump 13 can control the flow rate of the oil flow circuit. Since the flow rate Q=SV of the oil flow depends on the speed of the oil pump and the opening of the valve. Transformer oil can be regarded as an incompressible fluid. When an incompressible fluid flows steadily through the same flow tube, the flow rate of each cross section of the flow tube is the same at each moment. Therefore, based on the flow rate of the oil flow path and the equivalent area of ​​the cross section through which it flows, the oil flow velocity flowing through the contact surface can be calculated. It should be pointed out that due to the presence of metal contacts, the cross-sectional area through which the oil flow passes at the interface where the contacts are located is changed (that is, the equivalent interface area is reduced), resulting in a narrow tube effect, and the flow velocity flowing through the local surface of the contact will increase, while this effect can be ignored in practice. For fluids, there are also different flow states of laminar flow and turbulent flow. Therefore, the pipeline in the high-voltage test area should be designed to be of sufficient length to allow the liquid flow to fully develop. In order to simplify the problem, and considering that the maximum fluid velocity in practice is less than 1m / s, and no violent radial movement along the pipeline will occur, the issues of laminar flow and turbulent flow will not be specifically considered here.

[0030] In order to better understand this scheme, the principle of this scheme is described in detail below. At present, most large-capacity power transformers adopt an oil-immersed structure, and the oil-paper insulation system is used between the various units inside. Through the circulation of insulating oil, the heat generated by the winding during the operation of the transformer is brought to the heat sink and released into the surrounding environment. The presence of insulating oil can increase the insulation capacity between independent units that do not need to be electrically connected, so that short circuits will not occur inside. On the one hand, due to the widespread presence of corrosive sulfur and its compounds in the oil, it is easy to corrode the metal surface in a high temperature and strong electromagnetic environment, forming some complex complexes or chelates of metal organic matter. In this process, the metal particles released from the metal surface into the oil will exist in the insulating oil in the form of ions. On the other hand, as the only structure inside the transformer that can perform mechanical actions, the probability of failure of the on-load tap changer is correspondingly higher than that of other units. For the combined on-load tap changer, during the operation process, the metal contacts of the switching switch need to carry the task of opening and closing large currents for a long time and many times. Since the load current is cut off by opening and closing the moving and static contacts, an arc will be generated in this process. Under the action of the electric arc, the metal on the surface of the metal contact will splash into the surrounding insulating oil. The particles generated by the metal splashing can react chemically with the corrosive sulfides in the oil under high temperature to generate certain metal sulfides. It can be seen that in the above two processes, the corrosive sulfides in the transformer oil play a key role in the formation of metal particles in the oil. This experimental device is used to study the influencing factors of corona discharge and arc breakdown on the formation of metal ions in oil.

[0031] Please refer to Figure 3 , Figure 3 The block diagram is a module of a high-voltage test oil circuit unit according to an embodiment of the present invention. In a specific embodiment, the high-voltage test oil circuit unit 8 includes an oil circuit fixed base 28 having a pipeline structure 27, and a high-voltage connector and a low-voltage connector arranged on the oil circuit fixed base 28 and separated from each other. The pipeline structure 27 is formed with two connection ports. The high-voltage connector includes a high-voltage electrode connection conductor 18 partially extending into the pipeline structure 27, and the end of the high-voltage electrode connection conductor 18 located outside the pipeline structure 27 is connected to a high-voltage wire connector 24, and the end of the high-voltage electrode connection conductor 18 located inside the pipeline structure 27 is connected to a high-voltage electrode 16; the low-voltage connector includes a low-voltage electrode connection conductor 19 partially extending into the pipeline, and the end of the low-voltage electrode connection conductor 19 located outside the pipeline is connected to a low-voltage wire connector 25, and the end of the low-voltage electrode connection conductor 19 located inside the pipeline structure 27 is connected to a low-voltage electrode 17 or a grounding electrode, and the low-voltage electrode 17 and the high-voltage electrode 16 are separated from each other and arranged opposite to each other.

[0032] Specifically, the pipeline structure 27 of the oil circuit fixed base 28 can be set separately from the oil circuit fixed base 28, and the material of the pipeline structure 27 is specifically a resin material, which has better test performance. The pipeline structure 27 has a stacked high-voltage connector and a low-voltage connector, wherein the high-voltage connector is connected to the high-voltage area through a high-voltage wire connector 24, and the low-voltage connector is connected to the low-voltage area through a low-voltage wire connector 25, so that a pressure test can be performed. Further, the high-voltage connector has a high-voltage electrode 16, and the low-voltage connector has a low-voltage electrode 17. The high-voltage electrode 16 and the low-voltage electrode 17 are separated. In the test, the high-voltage electrode 16 and the low-voltage electrode 17 are filled with oil. Therefore, the generation of metal ions in the insulating oil can be obtained by loading the voltage on both sides of the high-voltage electrode 16 and the low-voltage electrode 17. It should be pointed out that a certain slope is designed at both ends of the above-mentioned pipeline structure 27 until the connection with the pipeline to prevent the oil sample from silting at some right-angle corners.

[0033] Specifically, the portion of the high-voltage electrode connection conductor 18 located outside the pipeline structure 27 is sleeved with a high-voltage area conductor insulating sleeve 20, and a high-voltage area limiting bolt 22 provided on the high-voltage electrode connection conductor 18 and used to fasten the high-voltage area conductor insulating sleeve 20; the portion of the low-voltage electrode connection conductor 19 located outside the pipeline structure 27 is sleeved with a low-voltage area conductor insulating sleeve 21, and a low-voltage area limiting bolt 23 provided on the low-voltage electrode connection conductor 19 and used to fasten the low-voltage area conductor insulating sleeve 21. Through the structural design of the connection, the stability of the structure can be tested.

[0034] Please refer to Figure 4 , Figure 4 The module block diagram of the temperature regulating and metering unit of one embodiment of the present invention. In a specific embodiment, it also includes a temperature regulating and metering unit 10 sleeved outside the pipeline between the pressure release unit 7 and the flow control valve 12, and the temperature regulating and metering unit 10 includes an electronic thermometer controller 28 arranged on the outside of the pipeline, and a water bath heating unit 29 and a refrigeration unit 30 sleeved on the outside of the pipeline, and the electronic thermometer controller 28 is electrically connected to the water bath heating unit 29 and the refrigeration unit 30 respectively. The cooperation of the above-mentioned water bath heating unit 29 and the refrigeration unit 30 can maintain the stability of the oil flow in the pipeline within the set range, and then determine the influence of the oil flow stability on the degradation of the metal contact.

[0035] In a specific embodiment, the water bath heating unit 29 is a water tank with a heating rod, and the refrigeration unit 30 is a heat dissipation ring. It is understandable that the water bath heating unit 29 can also adopt other heating units wound around the pipeline, and the heat dissipation ring can also be other heat dissipation units. In order to achieve more accurate temperature control, the heating unit and the heat dissipation unit are connected to an electronic thermometer controller.

[0036] In a specific embodiment, it also includes a flow rate metering unit 11 sleeved outside the pipeline between the pressure release unit 7 and the flow control valve 12, and the flow rate metering unit 11 is an ultrasonic flow meter. The ultrasonic flow meter does not need to contact the sample oil, and can obtain the corresponding oil flow rate through the oil pipeline. Since the flow rate of the oil flow in the capillary is different from the interface area passed by the electrical test pressurized area pipeline, the flow rate needs to be equivalently converted to obtain the approximate flow rate actually passing through the contact surface. The ultrasonic flow meter can detect the influence of the oil flow rate on the degradation of the metal contact.

[0037] Please refer to Figure 5 , Figure 5 The module block diagram of the pressure release unit of one embodiment of the present invention. In a specific embodiment, the pressure release unit 7 includes an exhaust valve 14, and a three-way adapter 15 connected to the exhaust valve 14 at one end, and the remaining two ends of the three-way adapter 15 are respectively connected to the high-pressure test oil circuit unit 8 and the flow control valve 12 through pipelines. The exhaust valve 14 is a float-type air release valve.

[0038] In a specific embodiment, the sampling tube 9 is a three-way structure, and the two ends of the sampling tube 9 are connected to the high-pressure test oil circuit unit 8 and the vacuum oil pump 13 through pipelines, and the remaining end is the sampling end. During the experiment, one end of the sampling tube 9 is closed, and the end has a valve for opening when sampling. When the valve is opened, two 20mL oil samples can be drawn with a syringe, and then an equal amount of fresh oil samples can be injected to maintain the oil volume inside the oil channel constant. Since the amount of oil sampled each time is negligible relative to the total oil volume in the oil channel, and an equal amount of fresh oil is injected, the oil flow in the pipeline is in a circulation process during the test, and it can be considered that the metal ions generated inside the oil at this time are evenly distributed. The metal content detected in each sample is closely related to the sampling time and the test conditions.

[0039] In a specific embodiment, the pipeline is a corrugated pipe, which can offset the effect of thermal expansion and contraction of oil on the pipeline.

[0040] When using the above simulation test device to carry out specific tests, the specific operating steps are as follows:

[0041] Step 1: Conduct a breakdown test of the electrode in oil in an open insulating oil pressure cup to determine the approximate breakdown voltage range. It should be noted that the breakdown voltage levels of contacts made of different materials or with different coatings will vary.

[0042] Step 2, build a test oil flow circuit, connect the high-voltage wire connector in the high-voltage test oil circuit unit 8 to the capacitive voltage divider, and ground the low-voltage wire connector.

[0043] Step 3, conduct a pressurization experiment and record the corresponding data. When sampling is required after completing a record, first shut down the test simulation device and discharge the high-voltage area with a grounding wire; then obtain the sample through the sampling valve and inject the same amount of oil sample to keep the total internal oil flow constant.

[0044] Step 4: For corona discharge and breakdown tests, after the discharge test is maintained for a certain period of time, the oil flow circuit must be vented to prevent excessive gas from being generated inside, which would cause greater pressure on the oil flow pipeline, especially the resin pipeline structure.

[0045] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical solution of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A simulation experimental device for the degradation mechanism of metal contacts of an on-load tap changer, characterized in that: The on-load tap changer metal contact degradation mechanism simulation experimental device comprises: an AC power input terminal, a booster, a test transformer, a current limiting protection resistor, a capacitor voltage divider and a test oil flow circuit electrically connected in sequence, the AC power input terminal is externally connected to AC power; the test oil flow circuit comprises a sampling tube, a high-voltage test oil circuit unit, a pressure release unit, a flow control valve and a vacuum oil pump connected in sequence through pipelines, the sampling tube is connected to the vacuum oil pump through a pipeline, the capacitor voltage divider is electrically connected to the high-voltage test oil circuit unit, the high-voltage test oil circuit unit comprises an oil circuit fixed base with a pipeline structure, and a high-voltage connector and a low-voltage connector arranged on the oil circuit fixed base and separated from each other, the pipeline structure is formed with two connection ports, the high-voltage connector comprises a high-voltage electrode connecting conductor partially extending into the pipeline structure, the high-voltage electrode connecting conductor is located in the A high-voltage wire connector is connected to one end outside the pipeline structure, and the end of the high-voltage electrode connecting conductor located in the pipeline structure is connected to the high-voltage electrode; the low-voltage connector includes a low-voltage electrode connecting conductor that partially extends into the pipeline, and the end of the low-voltage electrode connecting conductor located outside the pipeline is connected to a low-voltage wire connector, and the end of the low-voltage electrode connecting conductor located in the pipeline structure is connected to a low-voltage electrode or a grounding electrode, and the low-voltage electrode and the high-voltage electrode are separated from each other and arranged opposite to each other; it also includes a temperature regulating and metering unit outside the pipeline that is sleeved between the pressure release unit and the flow control valve, and the temperature regulating and metering unit includes an electronic thermometer controller arranged on the outside of the pipeline, and a water bath heating unit and a refrigeration unit sleeved on the outside of the pipeline, and the electronic thermometer controller is electrically connected to the water bath heating unit and the refrigeration unit, respectively.

2. The on-load tap changer metal contact degradation mechanism simulation experimental device according to claim 1, characterized in that: The portion of the high-voltage electrode connecting conductor located outside the pipeline structure is sleeved with a high-voltage area conductor insulating sleeve, and a high-voltage area limiting bolt is arranged on the high-voltage electrode connecting conductor and used to fasten the high-voltage area conductor insulating sleeve; The portion of the low-voltage electrode connecting conductor located outside the pipeline structure is sleeved with a low-voltage area conductor insulating sleeve, and a low-voltage area limiting bolt is arranged on the low-voltage electrode connecting conductor and used to fasten the low-voltage area conductor insulating sleeve.

3. The on-load tap changer metal contact degradation mechanism simulation experimental device according to claim 2, characterized in that: The material of the pipeline structure is resin material.

4. The on-load tap changer metal contact degradation mechanism simulation experimental device according to claim 1, characterized in that: The water bath heating unit is a water tank with a heating rod, and the refrigeration unit is a heat dissipation ring.

5. The on-load tap changer metal contact degradation mechanism simulation experimental device according to claim 1, characterized in that: It also includes a flow rate metering unit which is sleeved outside the pipeline between the pressure release unit and the flow control valve, and the flow rate metering unit is an ultrasonic flow meter.

6. The on-load tap changer metal contact degradation mechanism simulation experimental device according to claim 1, characterized in that: The pressure release unit includes an exhaust valve and a three-way adapter having one end connected to the exhaust valve, and the remaining two ends of the three-way adapter are respectively connected to the high-pressure test oil circuit unit and the flow control valve through pipelines.

7. The on-load tap changer metal contact degradation mechanism simulation experimental device according to claim 1, characterized in that: The sampling tube is a three-way structure, and both ends of the sampling tube are connected to the high-pressure test oil circuit unit and the vacuum oil pump through pipelines, and the remaining end is the sampling end.

8. The on-load tap changer metal contact degradation mechanism simulation experimental device according to any one of claims 1 to 7, characterized in that: The pipeline is a corrugated pipe.

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