Vacuum oil injection system for extra-high voltage converter transformer

Abstract

The utility model belongs to the converter transformer technical field relates to a kind of UHV converter transformer vacuum oil injection system, oil tank and converter transformer body top are equipped with auxiliary vacuum tank and transition vacuum tank, and complete set of pipe joint and valve are set on auxiliary vacuum tank and transition vacuum tank;The lower part of transition vacuum tank is communicated with the top of oil tank and converter transformer body, and the both ends of upper transparent hose and lower transparent hose are connected to the pipe joint of auxiliary vacuum tank and transition vacuum tank;The pipe joint of auxiliary vacuum tank is sealingly connected to cooler top, net elevated seat upper part, neutral point elevated seat upper part, valve elevated seat upper part and valve sleeve lower part by transparent hose, the upper part of auxiliary vacuum tank is sealingly communicated with vacuum unit by metal pipeline, and vacuum oil filter and the oil injection pipe joint of the lower part of oil tank and converter transformer body are sealingly connected.The utility model guarantees that oil tank and converter transformer body and accessory are completely vacuum oil injection, avoid the failure caused by oil being sucked into vacuum unit.

Description

Technical Field

[0001] This utility model belongs to the field of converter transformer technology, specifically relating to a vacuum oil injection system for ultra-high voltage converter transformers. Background Technology

[0002] After the UHV converter transformer is assembled, a vacuum oil filter and vacuum unit are needed to complete the vacuum oil injection.

[0003] Currently, a vacuum tank is typically used during vacuum oil filling. To ensure the quality of vacuum oil filling, two valve bushings, two valve riser seats, one grid riser seat, one neutral point riser seat, and all coolers must be vacuum-filled simultaneously with the oil tank and the converter transformer body. Since the vacuum tank is connected to the oil tank, the converter transformer body, and other accessories through vacuum pipelines, oil can easily enter the vacuum pipelines during filling. Oil entering the vacuum pipelines may cause vacuum unit malfunctions, and there may be incomplete vacuuming of accessories such as valve riser seats, valve bushings, grid riser seats, neutral point riser seats, and coolers, resulting in air trapped inside the accessories and affecting product quality. In particular, during the testing of ultra-high voltage converter transformers, partial discharge and other quality problems may occur. Summary of the Invention

[0004] To address the aforementioned technical problems, this utility model provides a novel vacuum oil injection system for ultra-high voltage converter transformers. The technical solution adopted by this utility model is as follows: A vacuum oil injection system for an ultra-high voltage converter transformer includes a vacuum oil filter and a vacuum unit. An auxiliary vacuum tank and a transition vacuum tank are installed on the top of the oil tank and the converter transformer body. The auxiliary vacuum tank and the transition vacuum tank are equipped with several sets of pipe joints and valves. The lower part of the transition vacuum tank is sealed and connected to the top of the oil tank and the converter transformer body. The upper and lower transparent hoses are respectively sealed and connected to the pipe joints of the auxiliary vacuum tank and the transition vacuum tank. The top of the cooler, the upper part of the grid riser, the upper part of the neutral point riser, the upper part of the valve riser, and the lower part of the valve sleeve are respectively sealed and connected to the pipe joints of the auxiliary vacuum tank through transparent hoses. The upper part of the auxiliary vacuum tank is sealed and connected to the vacuum unit through a metal pipeline. The vacuum oil filter is sealed and connected to the oil injection pipe joint at the bottom of the oil tank and the converter transformer body.

[0005] Preferably, the auxiliary vacuum tank includes an auxiliary vacuum tank body and support legs. Pipe joints are disposed on the side wall of the auxiliary vacuum tank body. Several support legs are disposed at the bottom of the auxiliary vacuum tank. Support circular plates are fixedly connected to the lower part of the support legs. Long studs are threadedly connected to the center of the support circular plates.

[0006] Preferably, bolt holes corresponding to long studs are opened on the reinforcing iron at the top of the oil tank and the converter transformer body, and the bolt holes are not connected to the interior of the oil tank and the converter transformer body.

[0007] Preferably, the transition vacuum tank includes an upper tank and a lower tank. The upper tank is a cylindrical structure with a closed top, and the lower tank is a cylindrical structure with open ends. The lower part of the upper tank and the upper part of the lower tank are fixedly connected as one unit by flanges and bolts. Pipe joints are provided on the side walls of the upper and lower tanks. The bottom of the lower tank is provided with a connector that communicates with the oil tank and the converter transformer body.

[0008] Preferably, an oil level gauge one is fixedly installed on the side wall of the upper tank, and an oil level gauge two is installed on the side wall of the lower tank.

[0009] Preferably, both the auxiliary vacuum tank and the transition vacuum tank are machined with lifting rings on their tops. Preferably, sealing rings are installed at each connection point.

[0010] The beneficial effects of this utility model are: This utility model innovatively employs two vacuum tanks. The lower interface of the transition vacuum tank is connected to the oil tank and the converter transformer body. The upper and lower parts of the transition vacuum tank are connected to the auxiliary vacuum tank. The auxiliary vacuum tank is connected to the cooler, riser seat, and valve sleeve. The upper interface of the auxiliary vacuum tank is connected to the vacuum unit. During evacuation, the auxiliary vacuum tank will never be filled with oil. Any residual gas that may remain during the vacuum oil filling process is concentrated in the auxiliary vacuum tank. After the vacuum oil filling is completed, the vacuum pipeline and the auxiliary vacuum tank are removed. This ensures that the oil tank, the converter transformer body, and all accessories are completely vacuum-filled, while also preventing oil from being sucked into the vacuum unit and causing malfunctions in the vacuum unit. Attached Figure Description

[0011] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a three-dimensional schematic diagram of the vacuum oil injection pipeline connection according to an embodiment of the present utility model; Figure 2 This is a top view of the ultra-high voltage converter transformer according to an embodiment of the present utility model; Figure 3 This is a three-dimensional structural diagram of the auxiliary vacuum tank according to an embodiment of the present invention; Figure 4 This is a three-dimensional structural diagram of the transition vacuum tank according to an embodiment of the present utility model; In the diagram, 1 is the cooler, 2 is the neutral point riser, 3 is the grid riser, 4 is the auxiliary vacuum tank, 5 is the oil tank and converter transformer body, 6 is the transition vacuum tank, 7 is the oil conservator, 8 is the valve riser A, 9 is the valve riser B, 10 is the valve sleeve a, 11 is the valve sleeve b, 12 is the vacuum oil filter, 13 is the vacuum unit, 14 is the support leg, 15 is the long stud, 16 is the support circular plate, 17 is the oil level gauge one, 18 is the oil level gauge two, 19 is the upper tank, and 20 is the lower tank. Detailed Implementation

[0012] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0013] like Figure 1 , 2 As shown, a vacuum oil injection system for an ultra-high voltage converter transformer includes an auxiliary vacuum tank 4 and a transition vacuum tank 6.

[0014] Two vacuum tanks, an auxiliary vacuum tank 4 and a transition vacuum tank 6, of similar height are configured in the vacuum oil injection pipeline. The transition vacuum tank 6 is directly connected to the oil tank and the inside of the converter transformer body 5. The connector at the bottom of the transition vacuum tank 6 is fixedly connected to the flange at the top of the oil tank and the converter transformer body 5. A sealing ring is placed at the connection point, and the bolts at the connection point are symmetrically, evenly, and reliably tightened to ensure sealing and prevent oil and air leakage. The bottom of the transition vacuum tank 6 is equipped with a connector that matches the flange at the top of the oil tank and the converter transformer body 5. The transition vacuum tank 6 can be directly fixedly connected to the oil tank and the converter transformer body 5 with bolts.

[0015] The auxiliary vacuum tank 4 is not directly connected to the oil tank and the converter transformer body 5. Figure 3 As shown, the main structural components of the auxiliary vacuum tank 4 include the auxiliary vacuum tank body, several sets of matching pipe fittings and valves, and support legs 14. The auxiliary vacuum tank body is a cubic sealed tank with a roughly square cross-section. The pipe fittings and valves are located on the side walls of the auxiliary vacuum tank body. A support leg 14 is fixedly installed at each of the four corners of the bottom of the auxiliary vacuum tank 4. The lower part of the support leg 14 is fixedly connected to a support circular plate 16, and a long stud 15 is threadedly connected to the center of the support circular plate 16. The auxiliary vacuum tank 4 is placed on top of the oil tank and the converter transformer body 5. The overall level of the auxiliary vacuum tank 4 is adjusted by rotating the long stud 15, so that the auxiliary vacuum tank 4 is placed horizontally on the upper part of the oil tank and the converter transformer body 5. Bolt holes can be made on the reinforcing iron on the upper part of the oil tank and the converter transformer body 5. Note that the bolt holes must not be connected to the inside of the oil tank and the converter transformer body 5. The lower end of the long stud 15 is screwed into the bolt holes to temporarily and reliably install the auxiliary vacuum tank 4, which also facilitates the removal of the auxiliary vacuum tank 4 later.

[0016] like Figure 4 As shown, the main structural components of the transition vacuum tank 6 include an upper tank body 19 and a lower tank body 20. The upper tank body 19 is a cylindrical structure with a closed top, while the lower tank body 20 is a cylindrical structure with open ends. The lower part of the upper tank body 19 and the upper part of the lower tank body 20 are fixedly connected as one unit by flanges and bolts. Pipe joints and valves are located on the side walls of the upper tank body 19 and the lower tank body 20. The bottom of the lower tank body 20 is provided with a connector that communicates with the oil tank and the converter transformer body 5. An oil level gauge 17 is fixedly installed on the side wall of the upper tank body 19, and an oil level gauge 28 is fixedly installed on the side wall of the lower tank body 20. Oil level gauges 17 and 28 facilitate observation of the oil level in the transition vacuum tank 6 during the oil filling process.

[0017] Both the auxiliary vacuum tank 4 and the transition vacuum tank 6 have integrally formed lifting rings on their tops, which facilitate the lifting and installation of the auxiliary vacuum tank 4 and the transition vacuum tank 6.

[0018] The highest point of one grid riser 3 (grid bushing A is installed on the upper part of grid riser 3), the highest point of one neutral point riser 2 (neutral point bushing B is installed on the upper part of neutral point riser 2), the highest point of two valve risers (the two valve risers include the upper valve riser A8 and the lower valve riser B9), and the highest point of two valve bushings (the two valve bushings include the upper valve bushing a10 and the lower valve bushing b11, wherein valve bushing a10 and valve bushing b11 are respectively fixedly installed on the upper part of valve riser A8 and valve riser B9) on the oil tank and converter transformer body 5 are connected to the auxiliary vacuum tank 4 with transparent flexible hoses. The connection points on the above components are equipped with special pipe joints and valves. When connecting grid riser 3, at least DN50 transparent flexible hoses are used, and at least DN25 transparent flexible hoses are used for the others. A vacuum gauge is installed on the top of the auxiliary vacuum tank 4.

[0019] At least four sets of coolers 1 are sealed at their highest points to the auxiliary vacuum tank 4 using transparent flexible tubes. The auxiliary vacuum tank 4 is sealed to the upper and lower parts of the transition vacuum tank 6 with a transparent flexible tube (two connections in total, ensuring effective vacuuming of the oil tank, converter transformer body 5, valve riser seat, and valve sleeve). When connecting the auxiliary vacuum tank 4 to the transition vacuum tank 6, at least a DN50 transparent flexible tube should be used at the upper part, and at least a DN25 transparent flexible tube should be used at the lower part; coolers 1 should be connected using at least a DN25 transparent flexible tube.

[0020] The upper part of the auxiliary vacuum tank 4 is sealed and connected to the vacuum unit 13. When connecting the vacuum unit 13, its own metal tube is used to connect the auxiliary vacuum tank 4. When connecting the vacuum unit 13 and the auxiliary vacuum tank 4, a conversion connector is used for a sealed connection. After connection, the metal tube is tied or supported and fixed to prevent the metal tube of the vacuum unit 13 from pulling on the auxiliary vacuum tank 4.

[0021] All pipe joints are fitted with sealing rings to ensure a reliable seal and prevent air or oil leaks.

[0022] Before starting the vacuuming process, all valves on the corresponding transparent hoses connecting the auxiliary vacuum tank 4 and the transition vacuum tank 6 are in the open position to ensure that the oil tank, the converter transformer body 5, the riser seat, the valve sleeve and the cooler 1 are evacuated simultaneously.

[0023] During the vacuuming process, leakage rate tests are performed on the oil tank and converter transformer body 5. Vacuum unit 13 is started to evacuate to a certain vacuum level (the vacuum level is read by the vacuum gauge at the auxiliary vacuum tank 4). Then, the valves at the connection points of the riser, cooler 1, valve sleeve, and transparent hose are closed. Vacuuming is stopped, and the valves between vacuum unit 13 and auxiliary vacuum tank 4 are closed. The leakage rate of the oil tank and converter transformer body 5 is measured to ensure that its sealing meets the design and process requirements of the converter transformer. The formula for calculating the leakage rate of the oil tank and converter transformer body 5 is as follows:

[0024] Where: △P = P2 - P1, P1 is the initial vacuum residual pressure value, P2 is the vacuum residual pressure value after 60 minutes, V is the volume of the oil tank (oil filling amount / 0.89), and T is the time (1 hour of detection is 3600 seconds).

[0025] In addition, a leakage rate test of the valve bushing vacuum pipeline is required. When the vacuum level of the oil tank and the converter transformer body 5 reaches the required vacuum level, a leakage rate test of the valve bushing and its vacuum pipeline is performed. The valve on the auxiliary vacuum tank 4 and the valve on the valve bushing are closed. After 10 minutes, the leakage rate of the valve bushing vacuum pipeline is measured. The valve bushing vacuum pipeline is opened only after the leakage rate is qualified.

[0026] Connect the vacuum oil filter 12 to the oil filling pipe joint at the bottom of the oil tank and the converter transformer body 5, and start the vacuum oil filter 12 and vacuum unit 13 to perform vacuum oil filling (vacuum unit 13 evacuates air outward, and vacuum oil filter 12 fills oil into the oil tank and the converter transformer body 5).

[0027] During vacuum oil filling, carefully observe each riser seat, valve sleeve and vacuum port of cooler 1. When oil is found coming out of the transparent hose at the vacuum port, wait until the transformer oil in the transparent hose is about 0.5m away from the auxiliary vacuum tank 4, close the valves at both ends of the transparent hose and continue to maintain the vacuum oil filling state.

[0028] Taking the vacuum oil filling of the valve riser seat and valve bushing as an example, since the valve riser seat and valve bushing are located on the side of the oil tank and the converter transformer body 5, oil will first come out of the transparent hoses at the lower valve riser seat B9 and valve bushing b11 during oil filling. When the oil in the transparent hoses at valve riser seat B9 and valve bushing b11 is about 0.5m from the auxiliary vacuum tank 4, the valves at both ends of the corresponding transparent hoses are immediately closed. This can prevent any gas that may be present in the oil tank and the converter transformer body 5 from entering the valve riser seat and valve bushing and affecting product quality.

[0029] The transition vacuum tank 6 is connected to the oil tank and the converter transformer body 5. As the oil level rises, transformer oil begins to enter the lower part of the transition vacuum tank 6. When the lower transparent hose connecting the transition vacuum tank 6 to the auxiliary vacuum tank 4 begins to discharge oil and the oil distance from the auxiliary vacuum tank 4 is about 0.5m, the valves at both ends of the lower transparent hose are closed. At this time, there is still no transformer oil in the auxiliary vacuum tank 4.

[0030] Continue vacuum oil injection. When the transition vacuum tank 6 is full of oil, the upper transparent hose connecting the transition vacuum tank 6 to the auxiliary vacuum tank 4 starts to discharge oil, and the oil is about 0.5m away from the auxiliary vacuum tank 4, close the valves at both ends of the upper transparent hose. This ensures that there is no air trapped in the transition vacuum tank 6. At this time, there is still no transformer oil in the auxiliary vacuum tank 4.

[0031] Continue vacuum oil injection. As the oil level continues to rise, the neutral point riser 2 and the cooler 1 will be filled with oil one after another. Similarly, when the oil in the transparent hose connecting the neutral point riser 2 and the cooler 1 is about 0.5m away from the auxiliary vacuum tank 4, immediately close the valves at both ends of the corresponding transparent hose. This ensures that there is no air trapped in the neutral point riser 2 and the cooler 1. At this time, there is no transformer oil in the auxiliary vacuum tank 4.

[0032] Vacuum oil injection continues until the highest grid riser 3 is completely filled with oil. At this point, transformer oil begins to flow from the transparent hose connected to the grid riser 3 into the auxiliary vacuum tank 4, ensuring no air trapped in the grid riser 3. After the transformer oil has flowed from the grid riser 3 into the auxiliary vacuum tank 4 for a period of time, i.e., when the oil level in the auxiliary vacuum tank 4 reaches a certain height, the valves at both ends of the transparent hose are closed, and the vacuum oil filter 12 and vacuum unit 13 are simultaneously shut down to stop vacuum oil injection. At this time, all the gas that may have been generated during the vacuuming process is concentrated in the auxiliary vacuum tank 4. The auxiliary vacuum tank 4 will be removed later, leaving only the transition vacuum tank 6, ensuring that no gas remains inside the above-mentioned components during the vacuum oil injection process. This effectively improves the efficiency and quality of vacuum oil injection for UHV converter transformers, thereby improving the quality of UHV converter transformers and avoiding the risk of rework. When removing the auxiliary vacuum tank 4, all the transformer oil in the transparent hose is collected into the auxiliary vacuum tank 4 to avoid waste.

[0033] Finally, the metal connecting pipe of vacuum unit 13 is removed from the transition vacuum tank 6 and moved to the breather flange of oil tank 7. The metal connecting pipe of vacuum unit 13 is then bolted to the breather flange of oil tank 7 for sealing connection. Vacuum oil filter 12 and vacuum unit 13 are started to continue vacuum oil injection until the oil level of oil tank 7 is reached as set by the process.

[0034] In this embodiment of the utility model, all technical features not described in detail are existing technologies or conventional technical means, and will not be repeated here.

[0035] Finally, it should be noted that the above embodiments are merely specific implementations of this utility model, used to illustrate the technical solution of this utility model, and not to limit it. The protection scope of this utility model is not limited thereto. Those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this utility model; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be covered within the protection scope of this utility model.

Claims

1. A vacuum oil injection system for an ultra-high voltage converter transformer, comprising a vacuum oil filter (12) and a vacuum unit (13), characterized in that, An auxiliary vacuum tank (4) and a transition vacuum tank (6) are installed on the top of the oil tank and the converter transformer body (5). The auxiliary vacuum tank (4) and the transition vacuum tank (6) are equipped with a number of sets of pipe joints and valves. The lower part of the transition vacuum tank (6) is sealed and connected to the top of the oil tank and the converter transformer body (5). The upper transparent hose and the lower transparent hose are respectively sealed and connected to the pipe joints of the auxiliary vacuum tank (4) and the transition vacuum tank (6). The top of the cooler (1), the upper part of the grid riser (3), the upper part of the neutral point riser (2), the upper part of the valve riser, and the lower part of the valve sleeve are respectively sealed and connected to the pipe joints of the auxiliary vacuum tank (4) through transparent hoses. The upper part of the auxiliary vacuum tank (4) is sealed and connected to the vacuum unit (13) through a metal pipeline. The vacuum oil filter (12) is sealed and connected to the oil injection pipe joint at the bottom of the oil tank and the converter transformer body (5).

2. The vacuum oil injection system for an ultra-high voltage converter transformer according to claim 1, characterized in that, The auxiliary vacuum tank (4) includes an auxiliary vacuum tank body and a support leg (14). The pipe joint is set on the side wall of the auxiliary vacuum tank body. Several support legs (14) are set at the bottom of the auxiliary vacuum tank (4). The lower part of the support leg (14) is fixedly connected to the support circular plate (16). The center position of the support circular plate (16) is threadedly connected to the long stud (15).

3. The vacuum oil injection system for an ultra-high voltage converter transformer according to claim 2, characterized in that, Bolt holes corresponding to long studs (15) are opened on the reinforcing iron at the top of the oil tank and converter transformer body (5). The bolt holes are not connected to the inside of the oil tank and converter transformer body (5).

4. The vacuum oil injection system for an ultra-high voltage converter transformer according to claim 1, characterized in that, The transition vacuum tank (6) includes an upper tank (19) and a lower tank (20). The upper tank (19) is a cylindrical structure with a closed top, and the lower tank (20) is a cylindrical structure with open ends. The lower part of the upper tank (19) and the upper part of the lower tank (20) are fixedly connected as one unit by flanges and bolts. Pipe joints are set on the side walls of the upper tank (19) and the lower tank (20). The bottom of the lower tank (20) is provided with a connector that communicates with the oil tank and the converter transformer body (5).

5. The vacuum oil injection system for an ultra-high voltage converter transformer according to claim 4, characterized in that, An oil level gauge 1 (17) is installed on the side wall of the upper tank (19), and an oil level gauge 2 (18) is installed on the side wall of the lower tank (20).

6. The vacuum oil injection system for an ultra-high voltage converter transformer according to claim 1, characterized in that, Both the auxiliary vacuum tank (4) and the transition vacuum tank (6) have lifting rings machined on their tops.

7. A vacuum oil injection system for an ultra-high voltage converter transformer according to claim 6, characterized in that, All connections are fitted with sealing rings.

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