Transformer bushing pressure test system

Abstract

The application relates to the technical field of transformers, and provides a transformer bushing withstand voltage test system, one end of the bushing is provided with an exhaust plug and a wiring terminal, the transformer bushing withstand voltage test system comprises an oil tank and a pressurizing device, the oil tank is provided with an oil inlet, the oil inlet is used for injecting transformer oil into the oil tank, the bushing is used for being connected to the oil tank, and the other end of the bushing away from the exhaust plug is inserted into the oil tank and is in communication with the oil tank; the pressurizing device is used for being electrically connected to the wiring terminal, so as to apply a test voltage to the bushing. The application can realize the off-line withstand voltage test of the transformer bushing, effectively reduces the test risk, and improves the test efficiency.

Description

Technical Field

[0001] This application relates to the field of transformer technology, and in particular to a transformer bushing withstand voltage test system. Background Technology

[0002] Transformer bushings are the main insulation devices outside the transformer box. The leads of the transformer windings must pass through the insulating bushings to insulate the leads from each other and from the transformer casing, while also fixing the leads in place.

[0003] When a transformer needs to have its bushings replaced, a withstand voltage test must be performed on the bushings to ensure that their quality meets the requirements for safe operation. Currently, online testing methods are generally used, which involve directly hoisting and installing the bushings onto the transformer for the withstand voltage test. This method is high-risk and inefficient. Utility Model Content

[0004] The purpose of this application is to provide a transformer bushing withstand voltage test system, which aims to solve the problems of high risk and low efficiency in existing online transformer bushing withstand voltage test methods.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] This application provides a transformer bushing withstand voltage test system, wherein one end of the bushing is provided with a vent plug and a terminal block, and the transformer bushing withstand voltage test system includes:

[0007] The oil tank is provided with an oil inlet for injecting transformer oil into the oil tank. The bushing is used to connect to the oil tank, and the other end of the bushing away from the vent plug extends into the oil tank and is connected to the oil tank.

[0008] A pressure-applying device is used to electrically connect the terminals to apply a test voltage to the bushing.

[0009] In some embodiments, the transformer bushing withstand voltage test system further includes:

[0010] A resistance measuring device is used to detect the insulation resistance of the bushing.

[0011] In some embodiments, the sleeve is used to be placed vertically on the top of the oil tank, the side of the oil tank is provided with the oil inlet, and the side of the oil tank is also provided with an oil outlet, the oil outlet being higher than the oil inlet.

[0012] In some embodiments, the side of the oil tank is provided with a viewing window for observing the oil level corresponding to the drain port, or the oil tank is provided with a liquid level sensor.

[0013] In some embodiments, the oil inlet is connected to a first flange, which is used to connect to an oil injection pipeline;

[0014] And / or, the drain port is connected to a second flange, which is used to connect to the drain pipeline.

[0015] In some embodiments, the sleeve is further provided with a third flange, the top of the oil tank is provided with an interface, the outer edge of the interface is provided with a fourth flange, the fourth flange is connected to the third flange, and the sleeve passes through the interface.

[0016] In some embodiments, the fourth flange is connected to the third flange via a fifth flange. The fifth flange includes a positioning tube and a first flange and a second flange connected to both ends of the positioning tube. The positioning tube is connected to the interface. The first flange is used to connect to the third flange via a first fastener, and the second flange is used to connect to the fourth flange via a second fastener.

[0017] In some embodiments, the first flange is provided with a plurality of first fastening holes and a plurality of second fastening holes, the centers of the plurality of first fastening holes are arranged in a circle with the center of the positioning tube as the center, the centers of the plurality of second fastening holes are arranged in a circle with the center of the positioning tube as the center, and the plurality of first fastening holes and the plurality of second fastening holes are arranged alternately.

[0018] The distance from the center of the first fastening hole to the center of the positioning tube is different from the distance from the center of the second fastening hole to the center of the positioning tube.

[0019] In some embodiments, the fuel tank is provided with at least one lifting lug.

[0020] In some embodiments, the pressurizing device is an AC withstand voltage test device.

[0021] The beneficial effects of the transformer bushing withstand voltage test system provided in this application are as follows: Compared with the prior art, this application simulates the actual transformer oil tank through an oil tank, and the inside of the bushing can be filled with transformer oil through oil injection and venting, which truly restores the insulation environment under the on-site operating conditions. The test voltage can be applied to the bushing through a pressurization device, thereby realizing the offline withstand voltage test of the transformer bushing. This can effectively reduce the test risk and improve the test efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of the transformer bushing withstand voltage test system provided in the embodiments of this application;

[0024] Figure 2 This is one of the structural schematic diagrams of the fuel tank provided in the embodiments of this application;

[0025] Figure 3 This is a second schematic diagram of the structure of the fuel tank provided in the embodiments of this application;

[0026] Figure 4 A schematic diagram of the structure of the fifth flange provided in an embodiment of this application from one perspective;

[0027] Figure 5 This is a structural schematic diagram of the fifth flange provided in an embodiment of this application from another perspective.

[0028] The following are the labeling elements in the figure:

[0029] 1. Sleeve;

[0030] 101. Vent plug; 102. Conductive rod; 103. Terminal block; 104. Third flange;

[0031] 2. Fuel tank;

[0032] 201. Oil inlet; 202. Oil drain; 203. Sight window; 204. First flange; 205. Second flange;

[0033] 206. Interface; 207. Fourth flange; 208. Fifth flange; 209. Positioning tube;

[0034] 210. First flange; 211. Second flange; 212. First fastening hole;

[0035] 213. Second fastening hole; 214. Lifting lug;

[0036] 3. Pressurization device;

[0037] 4. Cables. Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0039] In the description of the embodiments of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0041] In the embodiments of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0042] Transformer bushing 1 is the main external insulation device of the transformer tank. The leads of the transformer windings must pass through insulating bushing 1 to insulate between the leads and between the leads and the transformer casing, while also fixing the leads in place. During transformer operation, due to factors such as thermal expansion and contraction of the transformer oil and internal chemical reactions, some gases are generated and enter bushing 1. If not removed in time, this will affect the insulation performance of bushing 1 and the normal operation of the equipment. Figure 1As shown, the top of the bushing 1 is provided with a vent plug 101. The vent plug 101 can be a small valve device used to release gas inside the bushing 1, preventing insulation performance degradation or equipment failure due to gas accumulation. A conductive rod 102 is provided inside the bushing 1, with both ends of the conductive rod 102 exposed at both ends of the bushing 1. Terminals 103 are provided at both ends of the conductive rod 102. The terminal 103 at the bottom of the conductive rod 102 is connected to the lead wire of the transformer winding, and the terminal 103 at the top of the conductive rod 102 is used to connect external wires or equipment.

[0043] In some embodiments, refer to Figures 1 to 3 As shown, this application provides a transformer bushing withstand voltage test system. One end of the bushing 1 is provided with an exhaust plug 101 and a terminal block 103. The transformer bushing withstand voltage test system includes an oil tank 2 and a pressurizing device 3. The oil tank 2 is provided with an oil inlet 201 for injecting transformer oil into the oil tank 2. The bushing 1 is used to connect to the oil tank 2, and the other end of the bushing 1 away from the exhaust plug 101 extends into the oil tank 2 and is connected to the oil tank 2. The pressurizing device 3 is used to electrically connect to the terminal block 103 to apply a test voltage to the bushing 1.

[0044] The oil tank 2 is used to simulate the oil tank environment in an actual transformer. One or more oil inlets 201 can be installed on the oil tank 2, through which transformer oil can be injected. The bushing 1 can be installed on the oil tank 2 via a flange or other means. The lower end of the bushing 1, away from the vent plug 101, extends into the oil tank 2 and directly contacts the transformer oil inside. An oil passage hole can be provided at the lower end of the bushing 1 to establish communication with the oil tank 2. During oil injection, the transformer oil in the oil tank 2 can enter the bushing 1 through the oil passage hole. When the vent plug 101 is opened, the transformer oil can expel the air from the bushing 1, ensuring that the bushing 1 is filled with transformer oil to meet the insulation distance requirements during the withstand voltage test and to prevent electrical breakdown or partial discharge caused by the presence of air, thus avoiding affecting the accuracy of the test. Therefore, the oil tank 2 of this application not only provides physical support for the bushing 1 but also provides a closed space to store a certain amount of transformer oil, achieving a realistic simulation of the lower end of the bushing 1 being immersed in oil.

[0045] The pressurizing device 3 can be an AC withstand voltage test device, which can be connected to the terminal 103 on the top of the bushing 1 via cable 4 to form a closed loop, allowing current to pass through the bushing 1 to complete the test. The pressurizing device 3 is mainly used to apply a predetermined voltage to the bushing 1 to conduct a withstand voltage test, thereby verifying the insulation performance and mechanical stability of the bushing 1 under high voltage conditions, and ensuring that the bushing 1 can work safely and reliably under actual operating conditions. Specifically, the pressurizing device 3 can generate and apply a specific level of voltage to the bushing 1. This voltage can be set to a value higher than the normal operating voltage of the bushing 1 (e.g., 1.3 to 1.5 times the rated voltage) to test whether the bushing 1 can withstand such an overload without electrical breakdown, discharge, or other phenomena. In addition, the pressurizing device 3 can also monitor and record the changes in current and voltage during the test in real time and has overcurrent protection function.

[0046] The following is a general description of the test process of the transformer bushing withstand voltage test system provided in the embodiments of this application.

[0047] During the test, the bushing to be tested, 1, is installed on the test tank 2, with the lower end of 1 inserted into and connected to the tank 2, ensuring a good seal. The pressurizing device 3 is connected to the terminal 103 at the top of the bushing 1 via cable 4. To begin the test, the vent plug 101 at the top of the bushing 1 is opened to prepare for oil filling and venting. Transformer oil is injected through the oil inlet 201 on the tank 2; as the oil level rises, the transformer oil enters the bushing 1 from the bottom, and the air inside the bushing 1 is forced upwards and eventually discharged from the vent plug 101; when transformer oil begins to flow from the vent plug 101 without air bubbles, it indicates that the air inside the bushing 1 has been completely expelled. At this point, the vent plug 101 is closed to prevent oil leakage. The bushing 1 is now filled with transformer oil, meeting the insulation distance and dielectric conditions required for the withstand voltage test. Then, the pressurizing device 3 is started, and the voltage is slowly increased to the test voltage (e.g., 46.4kV or 76kV) and maintained for a certain period of time (e.g., 1 minute). If no abnormal phenomena such as discharge, corona, or overcurrent tripping occur during the test, it indicates that bushing 1 has good insulation performance and is of qualified quality. Conversely, if phenomena such as discharge, corona, or overcurrent tripping occur, it indicates that bushing 1 has insulation defects and is of unqualified quality.

[0048] Therefore, the transformer bushing withstand voltage test system provided in this application embodiment can detect the quality of bushing 1 in advance, reduce the number of rework due to quality issues after subsequent installation on the transformer, and realize offline withstand voltage test of transformer bushing 1. It eliminates the need to hoist and install bushing 1 on the actual transformer for testing, avoids high-risk behaviors such as high-altitude operations and live-line operations, significantly reduces test risks, and improves test efficiency.

[0049] In some embodiments, the transformer bushing withstand voltage test system further includes a resistance measuring device (not shown in the figure), which is used to detect the insulation resistance of the bushing 1.

[0050] A megohmmeter can be used to measure resistance. Depending on the bushing specifications and the operating environment, an appropriate test voltage (such as 500V, 1000V, 2500V, etc.) can be selected to avoid unnecessary damage to bushing 1.

[0051] This application allows for the measurement of the insulation resistance of bushing 1 using a resistance measuring device before applying high voltage, providing a preliminary assessment of its basic insulation condition and helping to identify any potential problems or defects, such as moisture, contamination, or aging. Furthermore, the insulation resistance of bushing 1 can be measured again after the withstand voltage test to confirm whether it has withstood the high voltage test without damage. Additionally, if the insulation resistance values ​​before and after the test are not significantly different and are both within the normal range, it indicates that bushing 1 is of good quality and meets the requirements for safe operation. If the insulation resistance value after the test is significantly lower than the value before the test, it indicates that bushing 1 has a quality problem.

[0052] Therefore, by introducing a resistance measuring device into the transformer bushing withstand voltage test system, the present application embodiment can enhance the system's detection capability, further ensure the insulation performance of bushing 1, and thus guarantee the quality of bushing 1 in use.

[0053] In some embodiments, refer to Figures 1 to 3 As shown, the sleeve 1 is used to be placed vertically on the top of the oil tank 2. The side of the oil tank 2 is provided with an oil inlet 201 and an oil outlet 202. The oil outlet 202 is higher than the oil inlet 201.

[0054] The top of the oil tank 2 is provided with an interface 206 for installing the sleeve 1. One or more oil inlets 201 can be provided on the side of the oil tank 2, and an oil inlet valve (not shown in the figure) can be installed at each oil inlet 201 to control its opening and closing. Furthermore, one or more oil outlets 202 can be provided on the side of the oil tank 2, and an oil outlet valve (not shown in the figure) can be installed at each oil outlet 202 to control its opening and closing. As an example, two oil inlets 201 are provided, located on opposite sides of the oil tank 2; two oil outlets 202 are provided, located on opposite sides of the oil tank 2.

[0055] When conducting batch tests on multiple bushings 1, the first bushing 1 is installed, the vent plug 101 at the top of the bushing 1 is opened, the oil injection valve is opened, and transformer oil is injected into the oil tank 2 through the oil injection port 201. When the bushing 1 is full of transformer oil and there is no gas, the vent plug 101 and the oil injection valve are closed to stop the oil injection. Then, a voltage is applied to the bushing 1 through the pressurizing device 3 to conduct a withstand voltage test. After the test is completed, the drain valve is opened, and the transformer oil in the oil tank 2 is drained to the height of the drain port 202 through the drain port 202. The drain valve is then closed. Then, the current bushing 1 is removed, the next bushing 1 is installed, the oil injection valve is opened, and a small amount of oil is added to the oil tank 2 through the oil injection port 201 to the appropriate oil level, quickly completing the preparation for re-oil injection, and the withstand voltage test of the next bushing 1 begins.

[0056] Understandably, since the top interface 206 of oil tank 2 is higher than the side drain port 202, the oil level is lowered to the height of the drain port 202 after the test. This prevents the transformer oil in oil tank 2 from overflowing from the top interface 206 when bushing 1 is being installed or removed. Furthermore, the design of the drain port 202 being higher than the filling port 201 allows for control of the oil discharge, eliminating the need to completely empty oil tank 2 and retaining a certain amount for subsequent tests. This means that only a small amount of oil needs to be added before the next test to reach the required oil level, saving time and resources and avoiding the need for large-scale oil filling and draining for each test, thus improving overall operational efficiency.

[0057] In some embodiments, refer to Figure 3 As shown, the side of the oil tank 2 is also provided with a viewing window 203, which is used to observe the oil level corresponding to the drain port 202.

[0058] To ensure a clear view, the viewing window 203 can be made of transparent materials, such as high-strength glass or polycarbonate. These materials not only have good light transmittance but can also withstand certain mechanical impacts and chemical corrosion. Furthermore, the viewing window 203 can be installed at the same height as the oil drain port 202, allowing for direct observation of the oil level at that port and facilitating operator monitoring. In addition, since transformer oil may condense due to temperature changes, affecting the transparency of the viewing window 203, a heating element can be installed on its surface to prevent condensation and ensure clarity.

[0059] The oil level in the tank 2 can be directly observed through the viewing window 203, ensuring that the oil level is accurately lowered to the drain port 202 during the draining process, avoiding over-draining or under-draining. This allows confirmation through the viewing window 203 that the oil level has been lowered to a safe level before installing the new sleeve 1, thus avoiding the risk of oil overflow during sleeve 1 replacement due to an excessively high oil level.

[0060] Therefore, by setting a window 203 on the oil tank 2, the embodiments of this application can significantly improve the visualization and ease of operation of the system, making oil level management more intuitive and efficient.

[0061] In some embodiments, a liquid level sensor (not shown) is provided inside the oil tank 2.

[0062] The specific type of liquid level sensor in this application is not particularly limited; for example, it can be a float-type liquid level sensor, a capacitive liquid level sensor, an ultrasonic liquid level sensor, etc. The liquid level sensor can continuously or periodically detect changes in the oil level in the oil tank 2, allowing operators to monitor the current oil level status at any time. Compared to manual judgment through window 203, the data provided by the liquid level sensor is more accurate.

[0063] In some embodiments, refer to Figure 2 and Figure 3 As shown, the oil inlet 201 is connected to a first flange 204, which is used to connect the oil inlet pipeline (not shown in the figure).

[0064] The oil filling pipeline can be connected to an oil filling pump (not shown in the figure). The oil filling pump is used to send transformer oil from the oil supply source (not shown in the figure) into the oil tank 2 through the oil filling pipeline and the oil filling port 201. The oil supply source can also be connected to an oil filter (not shown in the figure). The oil filter cleans the transformer oil supplied by the oil supply source before sending it into the oil tank 2, thereby ensuring that the quality of the transformer oil in the oil tank 2 is qualified and avoiding affecting the test results.

[0065] The oil filling port 201 of this application is connected to the oil filling pipeline through the first flange 204, which can realize the quick disassembly and assembly of the oil tank 2 and the oil filling pipeline, thereby facilitating transportation and on-site assembly.

[0066] In some embodiments, refer to Figure 2 and Figure 3 As shown, the drain port 202 is connected to a second flange 205, which is used to connect to the drain pipeline (not shown in the figure).

[0067] The drain line can be connected to a drain pump (not shown in the figure), which is used to send the transformer oil in the oil tank 2 back to the oil supply source through the drain port 202 and the drain line.

[0068] The oil drain port 202 of this application is connected to the oil drain pipeline by using the second flange 205, which can realize the quick disassembly and assembly of the oil tank 2 and the oil drain pipeline, thereby facilitating transportation and on-site assembly.

[0069] In some embodiments, refer to Figure 1 and Figure 2As shown, the sleeve 1 is also provided with a third flange 104, the top of the oil tank 2 is provided with an interface 206, the outer edge of the interface 206 is provided with a fourth flange 207, the fourth flange 207 is connected to the third flange 104, and the sleeve 1 passes through the interface 206.

[0070] When installing sleeve 1, the lower end of sleeve 1 can be inserted into oil tank 2 through interface 206 at the top of oil tank 2. The third flange 104 on the outside of sleeve 1 overlaps with the fourth flange 207 on the edge of interface 206. Then, the third flange 104 and the fourth flange 207 can be fastened together with bolts or other fasteners. To improve the connection sealing, sealing gaskets, sealing rings, or other sealing components can be installed at the connection between the third flange 104 and the fourth flange 207. This design in the embodiment of this application allows for quick assembly and disassembly of sleeve 1 and oil tank 2, thereby facilitating pressure testing of multiple sleeves 1.

[0071] In some embodiments, refer to Figures 1 to 5 As shown, the fourth flange 207 is connected to the third flange 104 via the fifth flange 208. The fifth flange 208 includes a positioning tube 209 and a first flange 210 and a second flange 211 connected to both ends of the positioning tube 209. The positioning tube 209 is connected to the interface 206. The first flange 210 is used to connect to the third flange 104 via a first fastener (not shown in the figure), and the second flange 211 is used to connect to the fourth flange 207 via a second fastener (not shown in the figure).

[0072] The fifth flange 208 can be a one-piece structure or a split structure. When the fifth flange 208 is a split structure, the positioning tube 209, the first flange 210, and the second flange 211 can be welded together to form the fifth flange 208. The positioning tube 209 serves as the main structure of the fifth flange 208, and its inner cavity communicates with the interface 206 at the top of the oil tank 2. The inner diameter of the positioning tube 209 matches the outer diameter of the sleeve 1, thereby guiding the sleeve 1 to be quickly and accurately inserted into the interface 206 at the top of the oil tank 2, improving installation convenience. The first flange 210 is located at one end of the positioning tube 209 and is connected to the third flange 104 on the sleeve 1 using a first fastener (such as a bolt). Sealing gaskets, sealing rings, and other sealing components can be installed at the connection point to improve the sealing performance. The second flange 211 is located at the other end of the positioning tube 209 and is connected to the fourth flange 207 at the top interface 206 of the oil tank 2 using a second fastener (such as a bolt). Sealing gaskets, sealing rings and other sealing components can also be installed at the connection to improve the sealing performance of the connection.

[0073] It is understandable that since bushings 1 of different voltage levels are usually equipped with third flanges 104 of different specifications, this application embodiment introduces a fifth flange 208 as an intermediate connecting part. By replacing different fifth flanges 208, bushings 1 of different flange standards can be adapted, thereby realizing the pressure resistance test of different bushings 1 and effectively improving the versatility of the system.

[0074] In some embodiments, refer to Figure 4 and Figure 5 As shown, the first flange 210 is provided with multiple first fastening holes 212 and multiple second fastening holes 213. The centers of the multiple first fastening holes 212 are arranged in a circle with the center of the positioning tube 209 as the center, and the hole positions are distributed to form a circumference. The centers of the multiple second fastening holes 213 are also arranged in a circle with the center of the positioning tube 209 as the center, and the hole positions are also distributed to form another circumference. The multiple first fastening holes 212 and multiple second fastening holes 213 are arranged alternately to ensure the symmetry and balance of the flange, which helps to disperse the stress generated during fastening, making the flange connection more stable and reducing the risk of leakage. The distance from the center of the first fastening hole 212 to the center of the positioning tube 209 is different from the distance from the center of the second fastening hole 213 to the center of the positioning tube 209, that is, the radii of the circumferences of the two sets of fastening holes are different.

[0075] It is understandable that high-pressure and low-pressure bushings 1 are typically equipped with third flanges 104 of different specifications, and the fastening hole distribution on the third flanges 104 of the high-pressure and low-pressure bushings is different. Therefore, in order to adapt to the fastening holes on the third flanges 104 of the high-pressure and low-pressure bushings, this application designs two different fastening hole distributions on the first flange 210 to correspond and connect with the fastening holes of the third flanges 104 on the high-pressure and low-pressure bushings. For example, when a pressure test is required on the high-pressure bushing 1, the fastening hole of the third flange 104 on the high-pressure bushing 1 can be connected to the first fastening hole 212 through the first fastener. When a pressure test is required on the low-pressure bushing 1, the fastening hole of the third flange 104 on the low-pressure bushing 1 can be connected to the second fastening hole 213 through the first fastener.

[0076] Therefore, by designing two different hole distributions for fastening holes on a single flange, this embodiment of the application can accommodate bushings 1 with different voltage levels (high and low voltage), reducing the need to replace flanges and thus improving the versatility and flexibility of the system.

[0077] In some embodiments, refer to Figure 2 and Figure 3 As shown, the oil tank 2 is equipped with at least one lifting lug 214.

[0078] Lifting lugs 214 can be installed on the top or side of the fuel tank 2 by means of screw connection or welding. Multiple lifting lugs 214 can be installed, symmetrically distributed on the top or side of the fuel tank 2 to ensure uniform force distribution, thereby guaranteeing balance and safety during lifting. The lifting lugs 214 provide lifting points for the fuel tank 2. When setting up the test system on site, cranes, gantry cranes, or other equipment can be connected to the lifting lugs 214 to achieve accurate and stable handling of the fuel tank 2, facilitating assembly.

[0079] In some embodiments, the bottom of the oil tank 2 is provided with a roller structure (not shown in the figure).

[0080] The roller structure may include multiple rollers, such as four, located at the four corners of the bottom of the oil tank 2 to ensure even force distribution and improve smooth movement. In this embodiment, the roller structure improves the mobility of the oil tank 2, facilitates quick position adjustments, and enhances assembly convenience.

[0081] The following describes the test process of the transformer bushing withstand voltage test system provided in this application with a specific example.

[0082] The oil tank 2 is roughly cuboid in shape, with a length, width, and height of 700mm. Two pairs of flanges of different sizes are symmetrically welded to the sides of the oil tank 2, namely the first flange 204 connected to the oil inlet 201 and the second flange 205 connected to the oil outlet 202. The fifth flange 208 on the top of the oil tank 2 is welded and formed, with an inner diameter of 150mm for its positioning tube 209. The diameters of the circumferences of the first fastening hole 212 and the second fastening hole 213 on the first flange 210 are 190mm and 210mm, respectively. The first fastening hole 212 and the second fastening hole 213 are arranged alternately to facilitate the interchangeability of high and low pressure bushings 1.

[0083] Connect the second flange 211 of the fifth flange 208 to the fourth flange 207 at the top interface 206 of the oil tank 2 using bolts. Then, install the third flange 104 of the high-pressure bushing 1 onto the first flange 210 of the fifth flange 208 and secure it firmly with bolts. The lower end of the high-pressure bushing 1 extends into the oil tank 2. The AC withstand voltage test device is connected to the terminal block 103 at the top of the bushing 1 via cable 4. Ensure that the bushing 1, oil tank 2, and AC withstand voltage test device are all grounded.

[0084] Open the oil injection valve and slowly inject qualified transformer oil into the oil tank 2 through the oil injection pipeline to immerse bushing 1. Observe the oil level through the viewing window 203 on the side of the oil tank 2. At the same time, open the vent plug 101 on the top of bushing 1. Stop the oil injection when oil overflows from the vent plug 101. Close the vent plug 101 and the oil injection valve to stop the oil injection.

[0085] The test begins by slowly increasing the voltage to the test voltage (e.g., 76kV) using an AC withstand voltage tester and maintaining this voltage for a certain period (e.g., 1 minute). During the test, if there are no abnormal phenomena such as discharge, corona, or overcurrent tripping, it indicates that bushing 1 has good insulation performance and is of acceptable quality. Conversely, if discharge, corona, or overcurrent tripping occurs, it indicates that bushing 1 has insulation defects and is of unacceptable quality.

[0086] After the test, open the drain valve and slowly drain the transformer oil in tank 2 to drain port 202 through the drain pipeline. Close the drain valve to prevent transformer oil from overflowing from tank 2 when replacing the next low-voltage bushing 1. After replacing low-voltage bushing 1, continue to fill tank 2 with oil through the filling pipeline until low-voltage bushing 1 is full. Then stop filling and conduct the test. The test voltage can be 46.4kV. Repeat this process to complete the withstand voltage test of multiple bushings 1.

[0087] Therefore, the transformer bushing withstand voltage testing system provided in this application can perform offline withstand voltage testing of transformer bushing 1, which can reduce testing risks and improve testing efficiency. Furthermore, by detecting the quality of bushing 1 in advance, the number of rework operations due to quality issues after installation on the transformer can be reduced, lowering the risk of replacement work and thus reducing labor and material costs. In addition, this application can meet the withstand voltage testing requirements of bushing 1 at different voltage levels, demonstrating versatility and flexibility.

[0088] The above are merely preferred embodiments of this application and are not intended to limit the embodiments of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A transformer bushing withstand voltage test system, wherein one end of the bushing is provided with an vent plug and a terminal block, characterized in that, The transformer bushing withstand voltage test system includes: The oil tank is provided with an oil inlet for injecting transformer oil into the oil tank. The bushing is used to connect to the oil tank, and the other end of the bushing away from the vent plug extends into the oil tank and is connected to the oil tank. A pressurizing device is used to electrically connect the terminals to apply a test voltage to the bushing.

2. The transformer bushing withstand voltage test system according to claim 1, characterized in that, The transformer bushing withstand voltage test system also includes: A resistance measuring device is used to detect the insulation resistance of the bushing.

3. The transformer bushing withstand voltage test system according to claim 1, characterized in that, The sleeve is used to be placed vertically on the top of the oil tank. The oil tank has an oil inlet on its side and an oil outlet on its side, which is higher than the oil inlet.

4. The transformer bushing withstand voltage test system according to claim 3, characterized in that, The side of the oil tank is also provided with a viewing window for observing the oil level corresponding to the drain port, or the oil tank is provided with a liquid level sensor.

5. The transformer bushing withstand voltage test system according to claim 3, characterized in that, The oil inlet is connected to a first flange, which is used to connect to the oil inlet pipeline. And / or, the drain port is connected to a second flange, which is used to connect to the drain pipeline.

6. The transformer bushing withstand voltage test system according to claim 1, characterized in that, The sleeve is also provided with a third flange, the top of the oil tank is provided with an interface, the outer edge of the interface is provided with a fourth flange, the fourth flange is connected to the third flange, and the sleeve passes through the interface.

7. The transformer bushing withstand voltage test system according to claim 6, characterized in that, The fourth flange is connected to the third flange via a fifth flange. The fifth flange includes a positioning tube and a first flange and a second flange connected to both ends of the positioning tube. The positioning tube is connected to the interface. The first flange is used to connect to the third flange via a first fastener, and the second flange is used to connect to the fourth flange via a second fastener.

8. The transformer bushing withstand voltage test system according to claim 7, characterized in that, The first flange is provided with a plurality of first fastening holes and a plurality of second fastening holes. The centers of the plurality of first fastening holes are arranged in a circle with the center of the positioning tube as the center, and the centers of the plurality of second fastening holes are arranged in a circle with the center of the positioning tube as the center. The plurality of first fastening holes and the plurality of second fastening holes are arranged alternately. The distance from the center of the first fastening hole to the center of the positioning tube is different from the distance from the center of the second fastening hole to the center of the positioning tube.

9. The transformer bushing withstand voltage test system according to claim 1, characterized in that, The fuel tank is equipped with at least one lifting lug.

10. The transformer bushing withstand voltage test system according to any one of claims 1 to 9, characterized in that, The pressurization device is an AC withstand voltage test device.

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