Testing device and method for simulating generation of solid impurities in transformer oil

Abstract

The invention discloses a test device and method for simulating generation of solid impurities in transformer oil, and relates to the field of power test devices and test mechanisms, the test device comprises a test cavity, and the test cavity is arranged to stimulate generation of the solid impurities and then mix the solid impurities with insulating oil in the test cavity; the filtering mechanism comprises a filter and a receiving container, the receiving container is communicated with the test cavity, the filter is arranged to filter the insulating oil which flows into the receiving container from the test cavity and contains the solid impurities, and the filter is further arranged to collect the solid impurities. According to the invention, the test mechanism and the filtering mechanism are communicated, so that a real solid impurity sample is prepared and is used for the subsequent test research on the influence mechanism of the impurities in the insulating oil, and the purposes of more appropriately simulating the actual form of the impurities in the insulating oil and simulating the actual operation conditions in the research on the impurities in the insulating oil are achieved.

Description

Technical Field

[0001] The invention relates to the field of electric power test devices, and in particular to a test device and a method for simulating the generation of solid impurities in transformer oil. Background Art

[0002] Oil-immersed power transformers are the core equipment of power grids. The good insulation performance of their insulation structure is the key to ensure the safe and stable operation of large power grids, and the performance of insulating oil is the focus of attention. However, transformers are in high temperature and high pressure operating environments for a long time, and the internal insulating oil will inevitably be contaminated by many particulate impurities. The appearance of these impurities will gradually distort the electric field distribution inside the transformer, increase the dielectric loss of the insulating oil, and bring huge safety hazards to the normal operation of the transformer. Therefore, many scholars have carried out research on the influence of solid impurities on the insulation performance of transformers.

[0003] Solid impurities in insulating oil mainly include free fibers, carbon black, and metal particles such as copper, iron, and alloys. During the operation of the transformer, the insulating paper must undergo electrical and thermal degradation processes, which will destroy the cellulose structure and form detached fiber impurities, which are mainly slender irregular impurities. After long-term operation, the transformer may have local discharge and overheating failures inside. The high concentration energy generated by the transformer is easy to crack and carbonize hydrocarbons such as insulating oil, forming a large amount of free carbon black, which is mainly presented in the microscopic form as impurity particles with high roundness but rough surface. Since the weight of fibers and carbon black is small, they are easy to form aggregation under the action of transformer electricity, heat, and flow field, threatening the insulation safety of transformers. Therefore, scholars currently focus on the research of fibers and carbon black impurities. Metal particles are mainly introduced during the wear and installation of transformer parts. Due to their large mass and the characteristics of being difficult to adhere, they are mostly deposited at the bottom of the transformer, which has little effect on the insulation performance, so there is less research on them. Therefore, the present invention mainly considers fiber and carbon black impurities.

[0004] At present, the research on impurities in insulating oil mostly uses industrial fiber microcrystals and carbon powder to simulate actual fiber and carbon black impurities for experimental research. However, in actual operation, due to the different forms of impurity particles in the oil, the mechanical and electrical processes involved under the action of multiple fields are also different. At present, there is a lack of relevant research that considers the actual form of impurities in oil and simulates actual operating conditions. This lack limits the in-depth research and analysis of the generation mechanism and influence mechanism of impurity particles, thus affecting the development and optimization of transformer insulation technology.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The purpose of the present invention is to provide a test device and method for simulating the generation of solid impurities in transformer oil. The device prepares real solid impurity samples by connecting a test mechanism and a filtering mechanism for subsequent experimental research on the influence mechanism of impurities in insulating oil, so as to solve the problem of low simulation accuracy of fiber microcrystals and carbon powder commonly used in the prior art.

[0007] The embodiment of the present invention is implemented by the following technical solution: The embodiment of the present invention provides a test device for simulating the generation of solid impurities in transformer oil, comprising:

[0008] A test mechanism, including a test chamber, wherein the test chamber is configured to stimulate the generation of solid impurities and then mix with the insulating oil in the test chamber;

[0009] The filtering mechanism comprises a filter and a receiving container. The receiving container is connected to the test cavity. The filter is configured to filter the insulating oil containing solid impurities flowing from the test cavity into the receiving container. The filter is also configured to collect the solid impurities.

[0010] Preferably, the solid impurities include fibrous impurities, and a heating mechanism is provided on the test cavity, the heating mechanism being configured to control the temperature inside the test cavity; when insulating paper and insulating oil are placed inside the test cavity, the heating mechanism can promote aging of the insulating paper inside the test cavity to prepare insulating oil containing fibrous impurities.

[0011] Preferably, the upper end of the test cavity is open, and the upper end of the test cavity is detachably covered with a sealing cover;

[0012] The heating mechanism is a heating sandwich member arranged on the side wall and the bottom wall of the test cavity, and the temperature of the heating sandwich member can be adjusted;

[0013] The sealing cover is provided with an air injection valve, a temperature sensor and a pressure release valve;

[0014] The air injection valve is used to introduce air or oxygen into the test chamber to accelerate the thermal aging of the insulation paper;

[0015] The temperature sensor is used to monitor the test temperature in the test chamber;

[0016] The pressure relief valve is used to release the air pressure in the test chamber.

[0017] Preferably, the solid impurities also include carbon black impurities, and an electrode mechanism is provided in the test chamber, and the electrode mechanism is configured to provide electrical energy for the electrical breakdown test;

[0018] When insulating oil is placed inside the test cavity, the electrode mechanism can electrically break down part of the insulating oil into carbon black impurities to prepare insulating oil containing carbon black impurities.

[0019] Preferably, the electrode mechanism comprises a positive electrode assembly and a negative electrode assembly, the positive electrode assembly passes through the test cavity, one end of the positive electrode assembly is located in the test cavity, and the other end is located outside the test cavity, and the end of the positive electrode assembly located outside the test cavity can be connected to the high voltage end of the power supply;

[0020] The negative electrode assembly passes through the test cavity, and one end of the negative electrode assembly is located in the test cavity, and the other end is located outside the test cavity, and the end of the negative electrode assembly located outside the test cavity can be connected to the ground terminal of the power supply;

[0021] There is a gap between the positive electrode assembly and the negative electrode assembly.

[0022] Preferably, the positive electrode assembly includes a positive guide rod and a positive electrode plate, and the negative electrode assembly includes a negative guide rod and a negative electrode plate, the positive electrode plate is connected to one end of the positive guide rod, and the negative electrode plate is connected to one end of the negative guide rod, and the positive electrode plate and the negative electrode plate are both located in the test cavity, the positive electrode plate and the negative electrode plate are arranged facing each other, and there is a gap between the positive electrode plate and the negative electrode plate;

[0023] A first nut is provided at the other end of the positive guide rod, and a second nut is provided at the other end of the negative guide rod. The positive guide rod passes through the test cavity, and the negative guide rod passes through the test cavity. The first nut can be connected to the high voltage end of the power supply, and the second nut can be connected to the ground end of the power supply.

[0024] The distance between the positive plate and the negative plate can be adjusted.

[0025] Preferably, a drainage hole is provided at the bottom of the test cavity, a drainage tube is connected to the drainage hole, a drainage valve is provided on the drainage hole or the drainage tube, and a filter is provided on the drainage tube;

[0026] The drainage tube is connected with an injection tube, which is provided with an injection valve. The connection between the injection tube and the drainage tube is located above the filter. The injection tube is configured to pass n-hexane solution into the filter to degrease solid impurities on the surface of the filter.

[0027] Preferably, the filter comprises a first filter station and a second filter station, the drainage pipe comprises an upper pipe and a lower pipe, the first filter station is connected to the upper pipe, the second filter station is connected to the lower pipe, the first filter station and the second filter station are both provided with filter screens facing one side, a filter membrane is arranged between the filter screen on the first filter station and the filter screen on the second filter station, and when the upper pipe is connected to the lower pipe, the filter membrane is clamped between the filter screen on the first filter station and the filter screen on the second filter station;

[0028] The first filter station and the second filter station are both provided with external threads, and the movable sleeve on the drainage tube is provided with a clamping cap, and the clamping cap is provided with an internal thread. The clamping cap can be connected with the threads of the first filter station and the second filter station to fix the first filter station and the second filter station together. At this time, the upper tube and the lower tube are sealed and connected.

[0029] In order to better solve the above problems, the present invention also provides a method for simulating the generation of solid impurities in transformer oil, which is implemented by the above experimental device and includes the following steps:

[0030] S1: Conducting an accelerated thermal aging test on insulating paper in a test chamber to obtain insulating oil containing fiber impurities, or conducting an electrode breakdown insulating oil test to obtain insulating oil containing carbon black impurities;

[0031] S2: Open the flow channel between the test cavity and the receiving container, and let the insulating oil containing solid impurities flow through the filter to filter out the solid impurities;

[0032] S3: Remove the filter, take out the solid impurities and dry them, and complete the preparation of fiber impurities or carbon black impurities.

[0033] Preferably, the process of the accelerated thermal aging test of the insulating paper comprises introducing the insulating oil and the insulating paper into the test cavity, and then heating the test cavity until the temperature reaches 85 to 95° C., and maintaining the temperature constant for 50 to 70 days;

[0034] The electrode breakdown insulating oil test involves repeatedly and continuously subjecting the dielectric oil to voltage breakdown in the test chamber until the insulating oil turns black.

[0035] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0036] 1. The test device for simulating the generation of solid impurities in transformer oil provided in the embodiment of the present invention includes a test mechanism and a filtering mechanism. The test cavity can provide a sealed reaction space for stimulating the generation of solid impurities and mixing them with the insulating oil in the cavity. The filtering mechanism includes a filter and a receiving container. The filter is arranged at the input end of the receiving container. Its function is to filter the insulating oil containing solid impurities to separate the solid impurities. In addition to the filtering function, the filter should also have the function of collecting the filtered solid impurities so as to further analyze and study the collected solid impurities. The embodiment of the present invention can prepare a real solid impurity sample by co-arranging the test mechanism and the filtering mechanism, which can replace the fiber microcrystals and carbon powder commonly used in the prior art, and improve the accuracy of the simulation test research.

[0037] 2. The test device provided in the embodiment of the present invention can prepare real samples of fiber impurities and carbon black impurities, wherein the fiber impurities are caused by the temperature adjustment of the heating mechanism, and the temperature in the test cavity is controlled in a sealed environment. The aging of the insulating paper placed in the test cavity is promoted by controlling the temperature in the test cavity. After aging, the insulating paper is mixed with the insulating oil in the test cavity to prepare insulating oil containing fiber impurities;

[0038] The carbon black impurities come from the electrode mechanism that partially electrically breaks down the insulating oil into carbon black impurities, so as to prepare the insulating oil containing carbon black impurities. The heating mechanism and the electrode mechanism can be set up as a whole with the test mechanism. During the actual operation, the heating mechanism and the electrode mechanism can be selectively started to improve the versatility of the entire device. The reactors for fiber impurities and carbon black impurities share a test chamber, and the preparation processes do not affect each other.

[0039] 3. When the electric field strength reaches a certain level, the positive electrode assembly and the negative electrode assembly in the electrode mechanism of the embodiment of the present invention will produce electric breakdown in the insulating oil between the two electrode assemblies, simulating the generation of carbon black impurities in the insulating oil. At the same time, the gap between the two electrode assemblies is set to an adjustable structure, which can simulate the electric breakdown behavior of the insulating oil under different gap conditions, provide experimental support for studying the impurity generation mechanism and optimizing the insulating properties of the insulating oil, increase the applicability and flexibility of the test device, and enable it to adapt to a wider range of research and testing needs.

[0040] 4. The embodiment of the present invention can prepare a more realistic solid impurity sample by providing an injection pipe to inject n-hexane solution into the filter to degrease the solid impurities, thereby laying a solid experimental foundation for the design and research of insulating oil-paper insulation. More importantly, the embodiment of the present invention can provide an integrated setting of testing, filtering, and degreasing, and provide a convenient and quick device and method steps for preparing solid impurities in insulating oil. The prepared solid impurities can more accurately simulate the solid impurities generated during the actual operation of the transformer.

[0041] 5. The method for simulating the generation of solid impurities in transformer oil provided by the embodiment of the present invention can prepare solid impurities of different qualities by flexibly changing the test conditions, thereby improving the richness of subsequent research and the reference value of data. The method can be completed in the test device provided by the embodiment of the present invention, and is simple to operate and highly flexible.

[0042] In general, the test device and method for simulating the generation of solid impurities in transformer oil provided in the embodiments of the present invention prepare real solid impurity samples by connecting the test mechanism and the filtering mechanism for subsequent experimental research on the influence mechanism of impurities in insulating oil, so as to achieve the purpose of more accurately simulating the actual form of impurities in insulating oil and simulating actual operating conditions in the research on impurities in insulating oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 A schematic diagram of the structure of a test device provided in an embodiment of the present invention;

[0045] Figure 2 An enlarged diagram of the structure of the test device provided in the embodiment of the present invention;

[0046] Figure 3 A schematic diagram of the filter structure provided by an embodiment of the present invention;

[0047] Figure 4 A process flow chart of a method for producing solid impurities provided in an embodiment of the present invention.

[0048] Marks and corresponding parts names in the attached drawings:

[0049] 100-test mechanism, 101-test chamber, 102-sealing cover, 103-heating sandwich, 104-gas injection valve, 105-temperature sensor, 106-pressure release valve, 107-positive electrode assembly, 108-negative electrode assembly, 109-positive guide rod, 110-positive plate, 111-negative guide rod, 112-negative plate, 113-first nut, 114-second nut, 115-drainage hole, 116-drainage tube, 117-upper tube, 118-lower tube, 119-drainage valve, 120-upper end cover, 121-lower end cover, 122-flat head screw, 123-wing nut, 124-self-sealing tube, 125-fastening nut, 126-insulating sleeve;

[0050] 200-filtering mechanism, 201-filter, 202-receiving container, 203-liquid injection pipe, 204-liquid injection valve, 205-first filter station, 206-second filter station, 207-filter membrane, 209-clamping cap, 210-liquid injection port, 211-liquid injector, 212-vacuum pump, 213-air guide pipe, 214-liquid discharge port, 215-support frame, 216-housing, 217-exhaust hole, 218-liquid discharge valve. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0052] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0053] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0054] In the description of the present invention, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0055] Example

[0056] Example 1: Figure 1-2 As shown, an embodiment of the present invention provides a test device for simulating the generation of solid impurities in transformer oil, comprising:

[0057] The embodiment of the present invention provides a test device for simulating the generation of solid impurities in transformer oil, including: a test mechanism 100, which is used to simulate the internal environment of the transformer, and can control conditions such as temperature and pressure, including a test cavity 101, and the test cavity 101 is configured to stimulate the generation of solid impurities and then mix with the insulating oil in the test cavity 101. For example, the aging of the insulating paper is accelerated by a heating mechanism to generate fiber impurities; or the electric breakdown is simulated by an electrode mechanism to generate carbon black impurities. A filtering mechanism 200 includes a filter 201 and a receiving container 202, and the receiving container 202 is connected to the test cavity 101. The filter 201 is configured to filter the insulating oil containing solid impurities that flows from the test cavity 101 into the receiving container 202, and the filter 201 is also configured to collect the solid impurities. Through this device, researchers can simulate the generation of solid impurities in insulating oil, study the impact of these impurities on the insulating properties of oil products, and develop and test new insulating materials and purification technologies. The invention provides a convenient and quick device and production conditions for preparing solid impurities in insulating oil. The prepared solid impurities can more accurately simulate the solid impurities generated during the actual operation of the transformer, replacing the fiber microcrystals and carbon powder commonly used in current experiments. It provides more realistic samples for experimental research on the microscopic morphology and composition of solid impurities, as well as the evaluation of the impact on oil-paper insulation performance, and lays a solid experimental foundation for the design and research of insulating oil-paper insulation.

[0058] Exemplarily, the solid impurities include fiber impurities, and a heating mechanism is provided on the test cavity 101, and the heating mechanism is configured to control the temperature inside the test cavity 101. When insulating paper and insulating oil are placed inside the test cavity 101, the heating mechanism can promote the aging of the insulating paper inside the test cavity 101 to prepare insulating oil containing fiber impurities. Specifically, the heating mechanism may include an electric heater, a hot wire or other suitable heating element, which is not limited here. As long as the purpose of sufficient temperature control function can be achieved, it is best to be able to evenly heat the inside of the test cavity 101 to ensure uniform aging of the insulating paper. The heating mechanism is configured to control the temperature inside the test cavity 101, and different temperature conditions can be set according to the requirements of different aging stages. During the aging process, the insulating paper may undergo thermal decomposition, oxidation and other reactions to produce fiber impurities, which will then be dispersed into the insulating oil. The aging of the insulating paper will cause the destruction of the cellulose structure and form fiber impurities. These fibrous impurities are slender and irregular in shape. Their dispersion and aggregation behavior in insulating oil is one of the research focuses. The generation of fibrous impurities simulates the formation process of solid impurities inside the transformer, which helps to study the impact of these impurities on the insulating properties of insulating oil.

[0059] By setting a heating mechanism in the embodiment of the present invention, the test device can simulate the generation process of fiber impurities in insulating oil, providing an experimental basis for studying the influence of fiber impurities on the insulating properties of insulating oil, which is of great significance for developing new insulating materials, improving the purification technology of insulating oil and improving the operating reliability of transformers.

[0060] As a preferred embodiment of the present invention, the upper end of the test cavity 101 is open, and the upper end of the test cavity 101 is detachably covered with a sealing cover 102; the heating mechanism is a heating interlayer member 103 arranged on the side wall and the bottom wall of the test cavity 101, and the temperature of the heating interlayer member 103 can be adjusted; the sealing cover 102 is provided with an injection valve 104, a temperature sensor 105 and a pressure release valve 106; the injection valve 104 is used to introduce air or oxygen into the test cavity 101 to accelerate the thermal aging rate of the insulating paper; the temperature sensor 105 is used to monitor the test temperature in the test cavity 101; the pressure release valve 106 is used to release the air pressure of the test cavity 101. Specifically, the upper end of the test cavity 101 is open to allow the test items to be placed in and taken out. The removable sealing cover 102 at the upper end ensures the sealing of the test cavity 101 during the heating process, prevents the leakage of oil and impurities, and also ensures the heating efficiency. The heating sandwich 103 is arranged on the side wall and bottom wall of the test cavity 101 to form a heating layer, which can be an electric heating wire, a thermal fluid circulation system or other suitable heating methods, ensuring uniform heating of the inside of the test cavity 101 to simulate the thermal environment inside the transformer. The temperature of the heating sandwich 103 can be adjusted to adapt to different aging conditions and experimental requirements. A plurality of functional valves are integrated on the sealing cover 102, including an injection valve 104, a temperature sensor 105 and a pressure release valve 106, which allow convenient operation and monitoring during the experiment. Specifically, the gas injection valve 104 is used to introduce air or oxygen into the test cavity 101 to increase the oxidizing atmosphere in the cavity, thereby accelerating the thermal aging rate of the insulating paper. By controlling the gas injection valve 104, different oxidation conditions that may occur inside the transformer can be simulated. The temperature sensor 105 is used to monitor the temperature in the test cavity 101 in real time to ensure the accuracy and controllability of the heating process. Temperature data is crucial for controlling the temperature of the heating interlayer 103 and is also very necessary for recording and analyzing experimental data. During the test, pressure accumulation may occur in the test cavity 101 due to heating and chemical reactions. The pressure release valve 106 is used to automatically or manually release the pressure when the pressure exceeds a preset safety value to prevent the cavity from rupturing or being damaged, thereby ensuring the safety of the experimental process.

[0061] In order to simulate the generation of carbon black impurities in insulating oil, an electrode mechanism is arranged in the test cavity 101. Exemplarily, the solid impurities also include carbon black impurities. An electrode mechanism is arranged in the test cavity 101, and the electrode mechanism is configured to provide electrical energy for the electrical breakdown test. When insulating oil is placed inside the test cavity 101, the electrode mechanism can electrically breakdown part of the insulating oil into carbon black impurities to prepare insulating oil containing carbon black impurities. More specifically, the electrode mechanism includes a positive electrode assembly 107 and a negative electrode assembly 108. The positive electrode assembly 107 passes through the test cavity 101, and one end of the positive electrode assembly 107 is located in the test cavity 101, and the other end is located outside the test cavity 101. The end of the positive electrode assembly 107 located outside the test cavity 101 can be connected to the high voltage end of the power supply; the negative electrode assembly 108 passes through the test cavity 101, and one end of the negative electrode assembly 108 is located in the test cavity 101, and the other end is located outside the test cavity 101. The end of the negative electrode assembly 108 located outside the test cavity 101 can be connected to the ground end of the power supply; there is a gap between the positive electrode assembly 107 and the negative electrode assembly 108. The electrode mechanism can effectively simulate the electrical breakdown phenomenon in the insulating oil, and then study the influence of the solid impurities generated thereby on the insulating properties of the insulating oil. This simulation test is of great significance for understanding and preventing the generation of solid impurities in the insulating oil.

[0062] As a preferred embodiment of the present invention, the positive electrode assembly 107 includes a positive guide rod 109 and a positive electrode plate 110, and the negative electrode assembly 108 includes a negative guide rod 111 and a negative electrode plate 112. The positive electrode plate 110 is connected to one end of the positive guide rod 109, and the negative electrode plate 112 is connected to one end of the negative guide rod 111. The positive electrode plate 110 and the negative electrode plate 112 are both located in the test cavity 101, and the positive electrode plate 110 and the negative electrode plate 112 are arranged opposite to each other, and there is a gap between the positive electrode plate 110 and the negative electrode plate 112; a first nut 113 is provided at the other end of the positive guide rod 109, and a second nut 114 is provided at the other end of the negative guide rod 111. The positive guide rod 109 passes through the test cavity 101, and the negative guide rod 111 passes through the test cavity 101. The first nut 113 can be connected to the high voltage end of the power supply, and the second nut 114 can be connected to the ground end of the power supply; the distance between the positive electrode plate 110 and the negative electrode plate 112 can be adjusted. Specifically, the positive plate 110 is located in the test chamber 101, and is used to form an electric field with the negative plate 112 during the test. The other end of the positive guide rod 109 is provided with a first nut 113, which is used to connect to the high voltage end of the power supply. The other end of the negative guide rod 111 is provided with a second nut 114, which is used to connect to the ground end of the power supply. There is an adjustable gap between the positive plate 110 and the negative plate 112. This gap is the key area for simulating the occurrence of electrical breakdown. The size of the gap can be adjusted according to the experimental needs to simulate the electrical breakdown phenomenon under different electric field strengths. Researchers can also control the intensity and uniformity of the electric field. The distance adjustment can be achieved by changing the position of the plate or using a bracket with a variable gap. The setting of the nut can improve safety and reliability to ensure stable connection under high voltage. The electrode mechanism of the embodiment of the present invention can not only effectively simulate the electrical breakdown phenomenon in insulating oil, but also provide precise control to study the electrical breakdown characteristics under different conditions.

[0063] As a preferred implementation of the embodiment of the present invention, a drainage hole 115 is provided at the bottom of the test chamber 101, a drainage tube 116 is connected to the drainage hole 115, a drainage valve 119 is provided on the drainage hole 115 or the drainage tube 116, and a filter 201 is provided on the drainage tube 116; the drainage tube 116 is connected to an injection tube 203, an injection valve 204 is provided on the injection tube 203, and the connection between the injection tube 203 and the drainage tube 116 is located above the filter 201, and the injection tube 203 is configured to pass an n-hexane solution into the filter 201 to degrease the solid impurities on the surface of the filter 201. Specifically, the injection tube 203 is used to inject liquid, such as n-hexane solution, into the filter 201 for degreasing. The injection tube 203 is set above the filter 201 to ensure that the liquid can be evenly distributed on the surface of the filter 201. The injection valve 204 is set so that it can be opened to allow solution injection, or closed to stop injection. This structure can degrease solid impurities on the surface of the filter 201 to remove grease and organic matter, which helps prevent the filter 201 from being blocked by grease and organic matter and maintain the filtration efficiency of the filter 201.

[0064] Furthermore, if Figure 3The filter 201 includes a first filter station 205 and a second filter station 206, the drainage pipe 116 includes an upper pipe 117 and a lower pipe 118, the first filter station 205 is connected to the upper pipe 117, the second filter station 206 is connected to the lower pipe 118, the first filter station 205 and the second filter station 206 are both provided with filter screens facing one side, and a filter membrane 207 is arranged between the filter screen on the first filter station 205 and the filter screen on the second filter station 206. When the upper pipe 117 is connected to the lower pipe 118, the filter membrane 20 7 is clamped between the filter screen on the first filter station 205 and the filter screen on the second filter station 206; the first filter station 205 and the second filter station 206 are both provided with external threads, and the drainage tube 116 is provided with a clamping cap 209 on the movable sleeve, and the clamping cap 209 is provided with an internal thread. The clamping cap 209 can be threadedly matched with the first filter station 205 and the second filter station 206 to fix the first filter station 205 and the second filter station 206 together. At this time, the upper tube 117 and the lower tube 118 are sealed and connected. Specifically, each filter station is provided with a filter screen on one side thereof, and the filter screen is used to intercept solid impurities. The filter membrane 207 is a permeable material used to capture finer impurities. When the upper tube 117 is connected to the lower tube 118, the filter membrane 207 is clamped between the filter screens of the two filter stations, ensuring that the solid impurities are effectively intercepted when the fluid passes through the filter membrane 207. The first filter station 205 and the second filter station 206 are fixed together by the clamping cap 209 and the thread of the filter station, ensuring the sealed connection between the upper tube 117 and the lower tube 118. This structure can facilitate the removal of the filter membrane 207 to remove and collect solid impurities. At the same time, it also makes the replacement of the filter membrane 207 and the maintenance of the filter 201 simple and quick. The setting of the clamping cap 209 provides a quick fastening and release mechanism, making the assembly and disassembly of the filter 201 more efficient.

[0065] In order to better implement the technical solution of the present invention, an embodiment 2 which is more preferred than embodiment 1 is also provided.

[0066] Specifically, Figure 1-3 As shown, the test device includes a test mechanism 100 and a degreasing mechanism and a filtering mechanism 200. The test mechanism 100 includes a test chamber 101, a heating interlayer member 103, a lower end cover 121, an upper end cover 120, a flat head screw 122, a wing nut 123, an injection valve 104, a pressure release valve 106, a self-sealing tube 124, a temperature sensor 105, a fastening nut 125, an insulating sleeve 126, a spherical nut (a first nut 113 and / or a second nut 114), a guide rod (a positive guide rod 109 and / or a negative guide rod 111), and a circular electrode plate (a positive electrode plate 110 and / or a negative electrode plate 112).

[0067] The degreasing mechanism and filtering mechanism 200 include a drainage hole 115, a drainage tube 116, an injection valve 204, a drain valve 218, an injection port 210, an injector 211, a filter 201, a receiving container, a vacuum pump 212, an air guide tube 213, an exhaust hole 217, a drain port 214, a support frame 215, and a housing 216.

[0068] Specifically, the test cavity 101 is a test space for generating solid impurities, and is used to accommodate test insulating oil and insulating paper; the heating interlayer 103 covers the four sides and the bottom of the test cavity 101, and a temperature-controllable heating plate is installed in the middle of the interlayer, and the adjustable temperature range is 0-200°C, which is mainly used to heat and control the temperature of the test cavity 101; the lower end cover 121 is connected to the test cavity 101; and the upper end cover 120 is sealed and fixed to the lower end cover 121 by four flat head screws 122 and wing nuts 123. During the test, the upper end cover 120 can be opened and closed by adjusting the wing nuts 123; the ball nut, the guide rod, and the circular plate are all connected by threads to form positive and negative electrodes, which are connected to an external high-voltage power supply. The guide rod passes through the insulating sleeve 126 to ensure good insulation and sealing effect with the heating interlayer 103 and the outer shell 216; the fastening nut 125 is a hollow nut with a sealing ring, and the guide rod passes through the fastening nut 125. The electrode is positioned and fixed by screwing the fastening nut 125, and the sealing of the test cavity 101 is ensured; the end cover is provided with an injection valve 104, a pressure release valve 106 and a temperature sensor 105; the temperature sensor 105 is inserted into the test cavity 101 through a self-sealing tube 124 to measure and control the temperature inside the cavity; the self-sealing tube 124 realizes temporary connection and disconnection between the inside and outside of the cavity at this location to ensure the sealing of the inside of the cavity.

[0069] A drainage hole 115 with a diameter of 50 mm is drilled at the bottom of the test cavity 101 and is arranged in the center. In order to prevent the insulating paper from falling into the hole, a thickened filter mesh is arranged at both ends of the drainage hole 115 in the embodiment of the present invention. The present embodiment selects a 50 mm, 10 mesh filter mesh; the filter 201 is a core device for filtration and degreasing, and its upper part is connected with the drainage pipe 116 and the drainage hole 115 in sequence, and a drainage valve 119 is installed between the filter 201 and the drainage hole 115. The opening and closing of the drainage valve 119 is used to control the flow of the test oil sample into the filter 201; in addition, the drainage pipe 116 between the filter 201 and the drainage valve 119 adopts a three-way pipe, and the other end of the three-way pipe is connected to the injection port 210. The injector 211 outside the positioning device is inserted into the injection port 210 to inject the n-hexane solution into the filter 201, so that the n-hexane solution is fully immersed in the solid impurities. The lower part of the filter 201 is connected to a drainage pipe 116, and the drainage pipe 116 is inserted into the receiving container 202; the neck of the receiving container 202 is provided with an outlet, which is connected to the vacuum pump 212 through the air guide pipe 213. When the vacuum pump 212 is working, a negative pressure is formed in the receiving container 202, and the test oil sample passes through the filter 201 and enters the receiving container 202, thereby achieving the purpose of impurity filtering, or the n-hexane solution is fully removed from the residual insulating oil in the solid impurities through the vacuum negative pressure; in addition, a drain port 214 is provided at the bottom of the side of the receiving container 202, and is led out of the device through the drainage pipe 116, which is convenient for sampling or waste liquid discharge after filtration, and a drain valve 218 is provided at the outlet to control the opening and closing; the exhaust hole 217 is connected to the exhaust hole 217 of the vacuum pump 212, and the gas generated when the vacuum pump 212 is working is discharged to the outside.

[0070] The support frame 215 is connected to the device housing 216 by screws to fix the vacuum pump 212; in addition, the housing 216 is closely attached to the heating interlayer. During the test, the housing 216 needs to be reliably grounded to ensure safety. Figure 3The filter 201 includes a filter station (including a first filter station 205 and a second filter station 206), a clamping cap 209 and a filter membrane 207. The surfaces of the upper and lower filter stations are threaded, and the opposite surfaces are installed with a filter screen with a larger aperture as a platform for placing the filter membrane 207, and a sealing ring is installed; the clamping cap 209 is sleeved with the upper pipe, and the inner part is threaded to match the surface of the filter station. The filter membrane 207 can be clamped between the filter stations by tightening the clamping cap 209. Considering that the fiber impurities and carbon black impurities obtained in the test are retained as much as possible, the filter membrane 207 used in the embodiment of the present invention is a polytetrafluoroethylene PTFE filter membrane 207 with a pore size of 1μm. The air injection hole also uses a self-sealing tube 124, and air or oxygen can be introduced into the cavity through the air injection hole to accelerate the thermal aging speed of the insulating oil paper. The test cavity 101 has a volume of 2L, and a slope inclined toward the center is provided at the bottom, and the inclination angle is set to 5 degrees to facilitate the liquid to concentrate toward the center. The electrode can move in the horizontal direction to control the distance of the gap; the spherical nut is connected to an external high-voltage power supply, and the spherical nut is connected to a ground wire; the entire electrode is detachable, and after disassembly, both ends of the insulating sleeve 126 can be sealed by a nut with a sealing end.

[0071] Embodiment 3: In order to better solve the problem of the present invention, the present invention also provides a method for simulating the generation of solid impurities in transformer oil, which is implemented by the above-mentioned experimental device, such as Figure 4 As shown, the following steps are included:

[0072] S1: Obtain insulating oil containing fiber impurities by conducting an accelerated thermal aging test of insulating oil paper by a testing agency 100, or obtain insulating oil containing carbon black impurities by conducting an electrode breakdown insulating oil test;

[0073] S2: Open the drainage valve 119 below the drainage hole 115, turn on the vacuum pump 212, and allow the test oil sample containing impurities to flow through the filter 201 to filter the impurities;

[0074] S3: Close the drainage valve 119 under the drainage hole 115, turn off the vacuum pump 212, open the injection valve 204 of the injection direction of the injection device 211, and inject the n-hexane solution into the filter 201 through the injection device 211. After the n-hexane solution flows through the filter membrane 207 with impurities attached, the insulating oil on the surface of the impurities can be removed to achieve the purpose of degreasing the impurities. For sufficient degreasing, the n-hexane solution should be slowly injected for about 3 minutes;

[0075] S4: Close the injection valve 204 of the injection device 211, remove the filter 201, unscrew the clamping cap 209, take out the filter membrane 207 and put it in a dry and clean culture dish. Place the culture dish at the vent for about 5 minutes to accelerate the volatilization of the residual n-hexane solution;

[0076] S5: Place the culture dish in a vacuum drying oven and dry it at 60°C and 50 Pa for 48 hours to obtain dry and pure solid impurities;

[0077] S6: Transfer the solid impurities into a reagent bottle and place the reagent bottle on an oscillator to fully shake for 30 minutes to ensure that the impurities are fully dispersed;

[0078] S7: Attach a label to the reagent bottle to complete the preparation of solid impurities (fiber impurities or carbon black impurities). The solid impurities can be used to carry out experimental research on the generation mechanism of impurity particles in insulating oil, transformer insulation performance evaluation, etc.

[0079] It should be noted that the generation of fiber impurities mainly depends on the thermal aging process of oil-paper insulation. Therefore, when preparing fiber impurities, in order to ensure the rigor and accuracy of the test, it is preferred to remove the positive electrode assembly 107 and the negative electrode assembly 108, and use a sealed nut to cover the insulating sleeve 126 to ensure the sealing of the test chamber 101. The process of generating fiber impurities may include the following steps:

[0080] S1: Prepare in advance some degassed and dried insulating papers and some filtered, degassed and dried insulating oils. Open the upper end cover 120 of the device, put the insulating paper into the test cavity 101, and introduce the insulating oil according to the highest aging oil-to-paper ratio of 10:1. Close the upper end cover 120, set the heating plate in the heating interlayer to heat to 90°C and keep the temperature constant. During the test, the temperature inside the cavity can be detected by the temperature sensor 105. The test time gradient is set to 60 days. In order to accelerate the aging rate of the insulating oil paper and obtain more detached fiber impurities, the embodiment of the present invention injects air into the test cavity 101 through the air inlet every 5 days, and slowly injects air for about 10 minutes each time. Since a pressure release valve 106 is provided at the end cover, there is no need to worry about damage to the device due to thermal expansion of the cavity;

[0081] S2: After the accelerated thermal aging is completed, the heating plate is turned off, the drainage valve 119 below the drainage hole 115 is opened, and the vacuum pump 212 is turned on to allow the test oil sample containing impurities to flow through the filter 201 below. Due to the negative pressure generated in the receiving container 202, the test oil sample will flow into the bottom receiving container 202 through the drainage pipe 116, while the fiber impurities will be left on the filter membrane 207, thereby achieving impurity filtration;

[0082] S3: After the test oil sample in the cavity is filtered, the drainage valve 119 below the drainage hole 115 is closed, the vacuum pump 212 is turned off, the injection valve 204 of the injection direction of the injection device 211 is opened, and the n-hexane solution is injected into the filter 201 through the injection device 211. After the n-hexane solution flows through the filter membrane 207 with fiber impurities attached, the insulating oil on the surface of the fiber impurities can be removed to achieve the purpose of degreasing the impurities. For sufficient degreasing, the n-hexane solution should be slowly injected for about 3 minutes;

[0083] S4: After degreasing, close the injection valve 204 of the injection device 211, remove the filter 201, unscrew the clamping cap 209, take out the filter membrane 207 with clean tweezers and place it in a dry and clean culture dish. Since the n-hexane solution is volatile and slightly toxic, place the culture dish at the ventilation port for about 5 minutes to accelerate the volatilization of the residual n-hexane solution and ensure the safety of the test personnel;

[0084] S5: Then, the culture dish is placed in a vacuum drying oven and dried for 48 hours at a temperature of 60° C. and an air pressure of 50 Pa to obtain dry and pure solid impurities;

[0085] S6: Due to negative pressure filtration, fiber impurities are compacted on the filter membrane 207. To fully disperse the fiber impurities, clean tweezers are used to carefully transfer the fiber impurities to the reagent bottle, and the reagent bottle is placed on an oscillator and fully shaken for 30 minutes to ensure that the impurities are evenly dispersed.

[0086] S7: After the shaking is completed, a label is attached to the reagent bottle to complete the preparation of fiber impurities. The prepared fiber impurities can more accurately simulate the fiber impurities generated during the actual operation of the transformer, replacing the industrially produced fiber crystallites commonly used in current experiments, and provide more realistic samples for experimental research on the microscopic morphology and composition of fiber impurities, as well as the impact evaluation of oil-paper insulation performance.

[0087] It should be noted that the above method and steps are for obtaining fiber impurities quickly and efficiently, so the thermal aging process of oil-paper insulation is accelerated by injecting air, but the operator may not inject air during use, and may set the aging time gradient, and may perform flexible sampling operations through the filtering mechanism 200 and the degreasing mechanism during the test. Since the generation and preparation process of carbon black impurities is similar to that of fiber impurities, a complete introduction is not given, and only the part that is different from the generation and preparation process of fiber impurities is introduced.

[0088] Specifically, when generating and preparing carbon black impurities, the test method used is the electrical breakdown of insulating oil. The installation of the test device is as shown in the attached Figure 2As shown, during the test, first fix the gap between the plates, and pour the filtered, degassed and dried insulating oil that can cover the plates into the test cavity 101. The spherical nuts at both ends of the electrodes are connected to the high voltage end and the ground end of the high voltage power supply respectively, and the device housing 216 is reliably connected to the ground end. Since the generation of carbon black impurities is related to the energy of electrical breakdown, the operator can use a high-capacity, high-voltage high-voltage power supply as appropriate. By repeatedly and continuously performing electrical breakdown on the insulating oil, a large amount of carbon black impurities can be generated in the oil. It should be noted that in order to improve the preparation efficiency, electrical breakdown can be performed as much as possible until the color of the insulating oil becomes obviously black.

[0089] The subsequent steps are the same as S2 to S7 in the fiber impurity preparation step, so they will not be repeated. Through the above steps, the carbon black impurities generated by the actual operation of the transformer can be prepared to replace the industrial carbon powder used in the current experimental research, providing a more realistic sample for the experimental research on the microscopic morphology and composition of carbon black impurities and the evaluation of the impact of oil-paper insulation performance.

[0090] In general, the test device and method for simulating the generation of solid impurities in transformer oil provided by the embodiment of the present invention can complete the accelerated thermal aging test of insulating oil paper and the electrical breakdown test of insulating oil, and thereby generate fiber impurities and carbon black impurities generated by the actual operation of the transformer; by designing a structure in which the drainage hole 115 is connected to the filtering and degreasing device, direct filtration and degreasing of the test oil sample are realized; and by designing a large-capacity cavity and a controllable valve, flexible sampling, filtration, and degreasing operations are realized during the experiment; the designed filter 201 can be flexibly disassembled, which is convenient for the subsequent processing and preparation process of standing, drying, and oscillating dispersion of impurities. The whole process is simple, fast, safe and reliable. The prepared solid impurities can fully simulate the solid impurity particles generated during the actual operation of the transformer. By using the prepared solid impurities, samples that are more in line with engineering practice can be provided for the study of the microscopic morphology and composition of the impurity particles, as well as the experimental study of the influence of the impurity particles on the insulation performance of the oil paper, and a solid experimental foundation condition is laid for the design and research of the insulating oil paper insulation.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. It should be noted that the structures or components illustrated in the accompanying drawings are not necessarily drawn to scale, and the present invention omits the description of known components and processing technologies and processes to avoid unnecessary limitations on the present invention.

Claims

1. A test device for simulating the generation of solid impurities in transformer oil, characterized in that: include: A test mechanism (100) comprises a test chamber (101), wherein the test chamber (101) is configured to stimulate the generation of solid impurities and then mix them with insulating oil in the test chamber (101); The filtering mechanism (200) comprises a filter (201) and a receiving container (202), wherein the receiving container (202) is in communication with the test cavity (101), and the filter (201) is configured to filter insulating oil containing solid impurities that flows from the test cavity (101) into the receiving container (202), and the filter (201) is further configured to collect the solid impurities.

2. A test device for simulating the generation of solid impurities in transformer oil according to claim 1, characterized in that: The solid impurities include fiber impurities. A heating mechanism is provided on the test cavity (101), and the heating mechanism is configured to control the temperature inside the test cavity (101). When insulation paper and insulation oil are placed inside the test cavity (101), the heating mechanism can promote aging of the insulation paper inside the test cavity (101) to prepare insulation oil containing fiber impurities.

3. A test device for simulating the generation of solid impurities in transformer oil according to claim 2, characterized in that: The upper end of the test cavity (101) is open, and the upper end of the test cavity (101) is detachably covered with a sealing cover (102); The heating mechanism is a heating sandwich member (103) arranged on the side wall and the bottom wall of the test cavity (101), and the temperature of the heating sandwich member (103) can be adjusted; The sealing cover (102) is provided with a gas injection valve (104), a temperature sensor (105) and a pressure release valve (106); The air injection valve (104) is used to introduce air or oxygen into the test cavity (101) to accelerate the thermal aging speed of the insulation paper; The temperature sensor (105) is used to monitor the test temperature in the test cavity (101); The pressure release valve (106) is used to release the air pressure in the test chamber (101).

4. A test device for simulating the generation of solid impurities in transformer oil according to any one of claims 1 to 3, characterized in that: The solid impurities also include carbon black impurities. An electrode mechanism is provided in the test cavity (101), and the electrode mechanism is configured to provide electrical energy for the electrical breakdown test. When insulating oil is placed inside the test cavity (101), the electrode mechanism can electrically break down part of the insulating oil into carbon black impurities, so as to prepare insulating oil containing carbon black impurities.

5. A test device for simulating the generation of solid impurities in transformer oil according to claim 4, characterized in that: The electrode structure comprises a positive electrode assembly (107) and a negative electrode assembly (108); the positive electrode assembly (107) passes through the test cavity (101); one end of the positive electrode assembly (107) is located inside the test cavity (101), and the other end is located outside the test cavity (101); the end of the positive electrode assembly (107) located outside the test cavity (101) can be connected to a high voltage end of a power source; The negative electrode assembly (108) passes through the test cavity (101), and one end of the negative electrode assembly (108) is located inside the test cavity (101), and the other end is located outside the test cavity (101), and the end of the negative electrode assembly (108) located outside the test cavity (101) can be connected to the ground terminal of a power source; There is a gap between the positive electrode assembly (107) and the negative electrode assembly (108).

6. A test device for simulating the generation of solid impurities in transformer oil according to claim 5, characterized in that: The positive electrode assembly (107) comprises a positive guide rod (109) and a positive electrode plate (110), and the negative electrode assembly (108) comprises a negative guide rod (111) and a negative electrode plate (112), the positive electrode plate (110) is connected to one end of the positive guide rod (109), and the negative electrode plate (112) is connected to one end of the negative guide rod (111), and the positive electrode plate (110) and the negative electrode plate (112) are both located in the test cavity (101), the positive electrode plate (110) and the negative electrode plate (112) are arranged facing each other, and there is a gap between the positive electrode plate (110) and the negative electrode plate (112); The other end of the positive guide rod (109) is provided with a first nut (113), and the other end of the negative guide rod (111) is provided with a second nut (114); the positive guide rod (109) passes through the test cavity (101), and the negative guide rod (111) passes through the test cavity (101); the first nut (113) can be connected to the high voltage end of a power supply, and the second nut (114) can be connected to the ground end of the power supply; The distance between the positive electrode plate (110) and the negative electrode plate (112) can be adjusted.

7. A test device for simulating the generation of solid impurities in transformer oil according to claim 1, characterized in that: The bottom of the test chamber (101) is provided with a drainage hole (115), the drainage hole (115) is connected to a drainage tube (116), the drainage hole (115) or the drainage tube (116) is provided with a drainage valve (119), and the filter (201) is provided on the drainage tube (116); The drainage tube (116) is connected to an injection tube (203), and an injection valve (204) is provided on the injection tube (203). The connection between the injection tube (203) and the drainage tube (116) is located above the filter (201). The injection tube (203) is configured to allow n-hexane solution to be introduced into the filter (201) so as to degrease solid impurities on the surface of the filter (201).

8. A test device for simulating the generation of solid impurities in transformer oil according to claim 7, characterized in that: The filter (201) comprises a first filter station (205) and a second filter station (206); the drainage pipe (116) comprises an upper pipe (117) and a lower pipe (118); the first filter station (205) is connected to the upper pipe (117); the second filter station (206) is connected to the lower pipe (118); the first filter station (205) and the second filter station (206) are both provided with filter screens facing one side; a filter membrane (207) is arranged between the filter screen on the first filter station (205) and the filter screen on the second filter station (206); when the upper pipe (117) and the lower pipe (118) are connected, the filter membrane (207) is clamped between the filter screen on the first filter station (205) and the filter screen on the second filter station (206); The first filter station (205) and the second filter station (206) are both provided with external threads, and the drainage tube (116) is provided with a clamping cap (209) on the movable sleeve, and the clamping cap (209) is provided with an internal thread. The clamping cap (209) can be threadedly matched with the first filter station (205) and the second filter station (206) to fix the first filter station (205) and the second filter station (206) together, and at this time, the upper tube (117) and the lower tube (118) are sealed and connected.

9. A method for simulating the generation of solid impurities in transformer oil, implemented by any one of the experimental devices of claims 1-8, characterized in that: The following steps are involved: S1: performing an accelerated thermal aging test on insulating paper in the test chamber to obtain insulating oil containing fiber impurities, or performing an electrode breakdown insulating oil test to obtain insulating oil containing carbon black impurities; S2: Open the flow channel between the test cavity and the receiving container, and let the insulating oil containing solid impurities flow through the filter to filter out the solid impurities; S3: Remove the filter, take out the solid impurities and dry them, and complete the preparation of fiber impurities or carbon black impurities.

10. The method for simulating the generation of solid impurities in transformer oil according to claim 1, characterized in that: The process of the accelerated thermal aging test of the insulating paper comprises introducing the insulating oil and the insulating paper into the test cavity, and then heating the test cavity until the temperature reaches 85 to 95° C., and maintaining the temperature constant for 50 to 70 days; The electrode breakdown insulating oil test includes repeatedly and continuously performing voltage breakdown on the transformer oil in the test chamber until the insulating oil turns black.

Images