A kind of oil tank structure for converter transformer valve side bushing test

Abstract

The present application belongs to the technical field of transformer manufacturing, and particularly relates to a kind of oil tank structures for valve side bushing test of converter transformer, a bell jar type oil tank is selected as the test oil tank body, an oil tank side wall is welded on the outer side of one end of the test oil tank body, a transverse and longitudinal combined structure is formed by welding a groove type reinforcing iron and a plate type reinforcing iron between the inner side of the oil tank side wall and the outer side of the test oil tank body, a triangular reinforcing plate is welded on the end of the test oil tank body close to the oil tank side wall, a hole is opened in the center of the oil tank side wall with a 40mm eccentricity and a method Lan is welded, a square cover plate special for valve side bushing is assembled on the method Lan, a lifting seat flange is fixedly installed on the square cover plate by bolts, and the shape of the lifting seat flange and the positioning position on the square cover plate are determined according to the valve side bushing to be tested. The present application can be applied to the valve side bushing test of various voltage levels commonly used at present, and has the advantages of simple structure, convenient operation, reliable valve side bushing structure assembly and high generalization degree.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of transformer manufacturing, and particularly relates to an oil tank structure for valve-side bushing test of a converter transformer. BACKGROUND

[0002] The converter transformer is one of the most important devices in a direct current transmission system, and its failure often leads to shutdown of the direct current system, causing economic loss and adverse social influence. According to statistics, 70% of the converter transformer failures are caused by valve-side bushings. Common valve-side bushing failures include flashover, heating, oil leakage, and seal failure. The valve-side bushing is different from the AC bushing, and it is directly connected to the valve-side winding and the converter valve, and bears a composite voltage composed of a direct current voltage and a severely distorted alternating current voltage. At the same time, it also bears lightning impulse voltage, operating impulse voltage, and polarity reversal voltage. The design and manufacture of the valve-side bushing are much more complex and difficult than those of the AC bushing, and it has become a significant weak point affecting the quality of the converter transformer.

[0003] The main voltage levels of the valve-side of the converter transformer are ±200kV, ±400kV, ±600kV, and ±800kV, and the weights of the valve-side bushings of different voltage levels are also different. With the continuous rise of the equipment manufacturing industry in China, the simulation, design, and manufacturing technologies of the converter transformer of the domestic manufacturers are continuously improved, and many transformer manufacturers have gradually possessed the ability to independently design and produce high-end and low-end converter transformers of different voltage levels. Excellent insulation electrical and mechanical performance indicators of the valve-side bushing are crucial for long-term safe and stable operation of the converter transformer, and improper handling may cause serious consequences such as explosion. Currently, the valve-side bushings commonly used in the power system in China are the HSP bushing from Germany and the ABB bushing from Sweden. The valve-side bushing of the converter transformer is generally arranged in the valve hall, which can not only reduce the creepage distance of the valve-side bushing by utilizing the good operating environment in the valve hall, but also prevent uneven wet flashover of the valve-side bushing.

[0004] In recent years, the valve-side bushings of the converter transformers of various manufacturers have been frequently involved in accidents such as moisture entering the bushing protection film due to improper transportation protection, improper protection at the converter station site, or hoisting operation errors in the factory, or the bushing impact recorder value exceeding the maximum allowable limit. According to the different insulation structures of the valve-side bushing, whether the electrical performance parameters such as the end screen insulation resistance, dielectric loss, and capacitance value of the valve-side bushing meet the requirements of the national standards and technical agreements is a very important means, and can be used as an important basis for whether the valve-side bushing can continue to be used on the product or returned to the factory for disassembly and repair. Timely elimination of risk factors through testing is crucial for safe operation of the equipment and safe and stable operation of the power system.

[0005] In order to comprehensively consider the economy and safety of the valve side sleeve test, the separate test of the valve side sleeve in the transformer manufacturing plant is a more reasonable and scientific method, and the test oil tank is one of the indispensable equipment in the test process. However, different valve side voltage levels have different requirements for the rated load of the test oil tank, and the existing test oil tank structure cannot meet the test requirements of different valve side voltage levels at the same time. SUMMARY

[0006] In view of the above technical problems, the application provides an oil tank structure suitable for valve side sleeve test of a converter transformer.

[0007] The technical scheme adopted by the application is:

[0008] The oil tank structure for valve side sleeve test of a converter transformer selects a bell jar type oil tank as a test oil tank body, welds an oil tank side wall on one end of the outer side of the test oil tank body, welds a transverse and longitudinal combined structure between the inner side of the oil tank side wall and the outer side of the test oil tank body by using groove type reinforcing iron and plate type reinforcing iron, welds a triangular reinforcing plate on one end of the inner side of the test oil tank body close to the oil tank side wall, opens a hole in the center of the oil tank side wall with a 40mm eccentricity and welds a method flange, assembles a square cover plate special for valve side sleeve on the method flange, and fixes and installs a lifting seat flange on the square cover plate through bolts. The shape of the lifting seat flange and the positioning position on the square cover plate are determined according to the valve side sleeve to be tested.

[0009] Preferably, the shape of the lifting seat flange is an oval or a square.

[0010] Preferably, the oil tank side wall is made of a 12mm thick Q235B ordinary carbon steel plate, a manhole is arranged at the lower left of the oil tank side wall and the test oil tank body, and a plurality of triangular reinforcing plates are uniformly arranged in the height direction.

[0011] Preferably, a grounding nut is arranged on the outer side of the square cover plate by welding, and lifting lugs are symmetrically arranged on the upper part of the square cover plate by welding.

[0012] Preferably, the inner width and height of the test oil tank body are not less than 3300mm and 4600mm respectively.

[0013] Preferably, the base of the method flange is welded on the oil tank side wall, the hole in the oil tank side wall is 20mm larger than the inner hole of the method flange on one side, the inner side edge of the method flange is chamfered with an R10 round corner, and the distance between the method flange and the groove type reinforcing iron and the plate type reinforcing iron is between 100mm and 115mm.

[0014] Preferably, the method is processed into a whole by using strip-shaped plate splicing and welding form, the strip-shaped plate selects the base material with width and thickness of 115mm and 40mm respectively, the sealing groove and thread hole are processed on the strip-shaped plate before splicing and welding, and the internal corner of the method is polished as a round corner.

[0015] Preferably, the groove width and groove height of the sealing groove are 13.4mm and 6.5mm respectively, the sealing groove is matched with a rubber strip with a diameter of 10mm, 92 M16 thread holes are uniformly processed on the method, and the 12.9 grade bolt is matched and used.

[0016] Preferably, the upper end inner side surface of the fourth strip-shaped plate is welded with the left end outer side surface of the first strip-shaped plate, the right end lower side surface of the first strip-shaped plate is welded with the upper end upper side surface of the second strip-shaped plate, the lower end inner side surface of the second strip-shaped plate is welded with the right end outer side surface of the third strip-shaped plate, and the left end upper side surface of the third strip-shaped plate is welded with the lower end lower side surface of the fourth strip-shaped plate, so as to be spliced into the method.

[0017] Preferably, the lifting seat is fixedly installed on the lifting seat flange through bolts, the valve side sleeve is fixedly installed on the lifting seat, and the outlet device and the sleeve tail equalizing ring are installed in the lifting seat.

[0018] The beneficial effects of the present application are as follows:

[0019] The present application can better solve the problem of separate test of the valve side sleeve in the transformer manufacturing plant, and the structure can be applied to the test and inspection of the valve side sleeve of various voltage grades at present, has the advantages of simple structure, convenient operation, reliable valve side sleeve structure assembly, high generalization degree, and can save the test cost to the maximum under the premise of meeting the test requirements. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the overall structure schematic diagram of the valve side sleeve test system of the embodiment of the present application;

[0021] Figure 2 is the overall structure top view of the valve side sleeve test system of the embodiment of the present application;

[0022] Figure 3-1 is the oil tank side wall welding schematic diagram of the embodiment of the present application;

[0023] Figure 3-2 is the oil tank side wall hole and method cooperation schematic diagram of the embodiment of the present application;

[0024] Figure 4 is the square cover plate installation schematic diagram of the method of the embodiment of the present application;

[0025] Figure 5 is the square cover plate installation lifting seat flange schematic diagram of the embodiment of the present application;

[0026] Figure 6-1 is the size diagram of the method for welding the strip plate group of the embodiment of the present application;

[0027] Figure 6-2 is the A-A sectional view of the embodiment of the present application; Figure 6-1

[0028] Figure 7 is the structure diagram of the method for welding the strip plate group of the embodiment of the present application.

[0029] In the figure, 1 is the oil tank side wall, 2 is the method for welding the strip plate group, 3 is the groove type reinforcing iron, 4 is the plate type reinforcing iron, 5 is the triangular reinforcing plate, 6 is the manhole, 7 is the square cover plate, 8 is the lifting seat, 9 is the valve side sleeve, 10 is the grounding nut, 11 is the lifting lug, 12 is the lifting seat flange, 13 is the sealing groove, 14 is the threaded hole, 15 is the first strip plate, 16 is the second strip plate, 17 is the third strip plate, and 18 is the fourth strip plate. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments.

[0031] As shown in Figure 1 , it is the overall structure diagram of the valve side sleeve test system of the embodiment of the present application; as shown in Figure 2 , it is the overall structure top view of the valve side sleeve test system of the embodiment of the present application, Figure 1 and Figure 2 contain the perspective effect, and the lower end of the triangular reinforcing plate 5 and the valve side sleeve 9 are located inside the oil tank. The valve side sleeve test system is to install the lifting seat 8 and the valve side sleeve 9 to be tested on the test oil tank body. The lifting seat 8 does not need to be specially designed and manufactured, and can be directly borrowed from the lifting seat used in the product matching of the converter transformer during the test, and the outlet device and the sleeve tail equalizing ring are installed inside the lifting seat 8. The outlet device and the equalizing ring are not embodied in Figure 1 . The structure and installation method of the lifting seat 8 and the valve side sleeve 9 are prior art, which will not be described here.

[0032] ​The application discloses a kind of oil tank structures for converter transformer valve side bushing test, suitable for the test of different voltage grade converter transformer valve side bushing test system, comprising: oil tank side wall 1, method Lan 2, groove type reinforcing iron 3, plate type reinforcing iron 4, triangular reinforcing plate 5, manhole 6, valve side bushing special square cover plate 7, grounding nut 10, lifting lug 11 and lifting seat flange 12.The embodiment of the application selects conventional 110kV or 220kV bell jar oil tank as the basic carrier structure of the test oil tank body, and the inner width and height of the test oil tank body are required to be not less than 3300m and 4600mm respectively in principle, which can meet the minimum insulation distance required by the valve side bushing 9 test and the installation space of the valve side bushing 9 inclined insertion assembly.

[0033] As Figure 3-1 shown, it is the oil tank side wall welding schematic diagram of the embodiment of the application, which contains perspective effect, and shows the components inside the oil tank side wall and the test oil tank body.In the outer side of one end of the test oil tank body, 12mm thick Q235B ordinary carbon steel plate is welded as oil tank side wall 1, in order to ensure the strength of the oil tank side wall 1, groove type reinforcing iron 3 and plate type reinforcing iron 4 are welded into horizontal and vertical combined structure between the inner side of the oil tank side wall 1 and the outer side of the test oil tank body, wherein the horizontal plate type reinforcing iron 3 is welded together with the reinforcing iron of the outer side of the test oil tank body by extending corner mode, and in addition, triangular reinforcing plate 5 is welded in the inner part of the test oil tank body close to one end of the oil tank side wall 1, the side of the triangular reinforcing plate 5 is welded with the inner side of the end and the front inner side or the rear inner side respectively, and the triangular reinforcing plate 5 is uniformly arranged in the height direction, and the whole reinforcing rib structure is formed on the oil tank side wall 1 by the above welding combination.In order to facilitate the installation and adjustment of the valve side bushing 9 and the insulation accessories inside the lifting seat 8, manhole 6 is arranged at the lower left of the oil tank side wall 1 and the test oil tank body, and the operator can conveniently enter and exit the test oil tank body and observe the work through the manhole 6.In the center of the oil tank side wall 1, hole is opened with eccentricity of 40mm and method Lan 2 is welded, the eccentricity of 40mm is to design the manhole 6, and the base of the method Lan 2 is welded on the oil tank side wall 1, wherein the opening on the oil tank side wall 1 is 20mm larger than the inner side hole of the method Lan 2 on single side, and in order to ensure that the live part of the valve side bushing 9 corresponds to the electrode shape of the method Lan 2, R10 round corner needs to be turned on the inner side edge of the method Lan 2, as Figure 3-2 shown, it is the oil tank side wall opening and method Lan cooperation schematic diagram of the embodiment of the application.In addition, the distance between the method Lan 2 and the groove type reinforcing iron 3 and the plate type reinforcing iron 4 is preferably between 100mm to 115mm, and the distance is selected by fully considering the thermal stress deformation of welding and the overall mechanical strength of the reinforcing rib.

[0034] A square cover plate 7, specifically for the valve side sleeve, is mounted on the flange 2. A grounding nut 10 is welded to the outer surface of the square cover plate 7. The grounding nut 10 reliably connects the flange 2 to the side wall 1 of the oil tank and grounds it. For example... Figure 4 The diagram shown is a schematic diagram of a square cover plate installed on a flange according to an embodiment of the present invention; as shown Figure 5 The diagram shown is a schematic of the installation of a riser flange on a square cover plate according to an embodiment of the present invention. Lifting lugs 11 are symmetrically welded onto the upper part of the square cover plate 7, facilitating the lifting of the square cover plate 7. The riser flange 12 is bolted to the square cover plate 7. The riser flange 12 needs to be re-machined according to the valve side sleeve 9 to be tested. By adjusting the shape of the riser flange 12 (which can be elliptical, square, etc.) and its positioning on the square cover plate 7, applicability to different angles of valve side sleeves 9 for different voltage levels can be achieved.

[0035] In this embodiment of the invention, a novel method flange 2 is fabricated by welding strip plates together. The overall dimensions of the flange after fabrication are as follows: Figure 6-1 As shown. The strip plate uses base material with a width of 115mm and a thickness of 40mm, made of low-alloy steel plate Q355D. Before welding, sealing grooves 13 and threaded holes 14 need to be machined on the strip plate. Figure 6-2 After the dimensions are machined, the strip plates are welded together. Finally, the welded flange 2 is ground to the specified roughness, and the internal corners are rounded. The sealing groove 13 of flange 2 has a width of 13.4mm and a height of 6.5mm, which is matched with a 10mm diameter rubber strip. During assembly, the rubber strip length can be matched according to flange 2. The advantage of using a round rubber strip as a sealing gasket is that the on-site matching of the rubber strip can effectively compensate for the manufacturing error during the machining and welding of flange 2, ensuring the sealing effect between flange 2 and square cover plate 7. This specification of flange 2 is the first design to be used on the test tank of a converter transformer. The selection of strip plates with a width of 115mm and a thickness of 40mm fully considers its welding deformation performance and overall mechanical strength after processing. In addition, 92 M16 threaded holes are machined and used with 12.9 grade bolts. The square cover plate 7 is fixedly installed on flange 2 by using 12.9 grade bolts with M16 threaded holes. Calculations have verified that it can bear a rated load of 16T.

[0036] like Figure 7As shown, it is the structure schematic diagram of the strip-shaped plate assembly welding method of the embodiment of the present application. The upper end inner side surface of the fourth strip-shaped plate 18 is welded with the left end outer side surface of the first strip-shaped plate 15, the right end lower side surface of the first strip-shaped plate 15 is welded with the upper end upper side surface of the second strip-shaped plate 16, the lower end inner side surface of the second strip-shaped plate 16 is welded with the right end outer side surface of the third strip-shaped plate 17, the left end upper side surface of the third strip-shaped plate 17 is welded with the lower end lower side surface of the fourth strip-shaped plate 18, and the assembly welding is the method 2.

[0037] In the embodiment of the present application, through the optimized matching design and size arrangement between components, the oil tank structure for valve side bushing test of the converter transformer can bear the rated weight 18T of the valve side bushing 9, and the weight of the currently operated valve side bushing 9 of different voltage levels is less than the rated test load. In addition, due to the arrangement of the valve side bushing 9, the connection with the internal valve lead of the oil tank and the minimum air distance of the top live part in the valve hall to the ground and to the firewall need to be considered at the same time, the oblique insertion angles of all valve side bushings 9 on the sidewall of the oil tank are different. In order to restore the actual installation and operation state of the valve side bushing 9 in the converter transformer body to the greatest extent during the test of the valve side bushing 9, the present application ingeniously utilizes the size and installation matching of the method 2 and the special cover plate 7 for bushing, thereby realizing the universality of the test of the valve side bushing 9 of different voltage levels. Through the above-mentioned test oil tank structure design, the test and inspection of the valve side bushing 9 of different voltage levels can be realized, the overall design structure is simple, the assembly is reliable, the mechanical strength is high, and the economic performance is optimal.

[0038] In the embodiment of the present application, the technical features not described in detail are all prior art or conventional technical means, which will not be described here.

[0039] Finally, it should be noted that: the above embodiments are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not to limit it. The protection scope of the present application is not limited to this. Those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions recorded in the above embodiments within the technical range disclosed by the present application, or make equivalent replacement to some technical features; and these modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and all should be covered in the protection scope of the present application.

Claims

1. A tank structure for a converter transformer valve side bushing test, characterized by, The bell-shaped oil tank is selected as the test oil tank body, the oil tank side wall (1) is welded on one end of the outer side of the test oil tank body, the groove-shaped reinforcing iron (3) and the plate-shaped reinforcing iron (4) are welded between the inner side of the oil tank side wall (1) and the outer side of the test oil tank body in a transverse and longitudinal combined structure, the triangular reinforcing plate (5) is welded on one end of the inner side of the test oil tank body close to the oil tank side wall (1), the method flange (2) is welded on the center of the oil tank side wall (1) with a 40mm hole, the base of the method flange (2) is welded on the oil tank side wall (1), the hole on the oil tank side wall (1) is larger than the inner hole of the method flange (2) by 20mm on one side, the inner edge of the method flange (2) is rounded with R10, the distance between the method flange (2) and the groove-shaped reinforcing iron (3) and the plate-shaped reinforcing iron (4) is between 100mm and 115mm, the method flange (2) is processed into an integral whole in the form of strip-shaped plate splicing, the strip-shaped plate is made of base material with a width of 115mm and a thickness of 40mm, the sealing groove (13) and the threaded hole (14) are processed on the strip-shaped plate before splicing, the inner corner of the method flange (2) is polished to be rounded, the square cover plate (7) special for the valve side sleeve is assembled on the method flange (2), the lifting seat flange (12) is fixedly installed on the square cover plate (7) through bolts, the shape of the lifting seat flange (12) and the positioning position on the square cover plate (7) are determined according to the valve side sleeve (9) to be tested; The upper end inner side of the fourth strip-shaped plate (18) is welded with the left end outer side of the first strip-shaped plate (15), the right end lower side of the first strip-shaped plate (15) is welded with the upper end upper side of the second strip-shaped plate (16), the lower end inner side of the second strip-shaped plate (16) is welded with the right end outer side of the third strip-shaped plate (17), the left end upper side of the third strip-shaped plate (17) is welded with the lower end lower side of the fourth strip-shaped plate (18), and the four strip-shaped plates are spliced into the method flange (2); The lifting seat (8) is fixedly installed on the lifting seat flange (12) through bolts, the valve side sleeve (9) is fixedly installed on the lifting seat (8), and the outlet device and the sleeve tail equalizing ring are installed in the lifting seat (8).

2. The oil tank structure for converter transformer valve side bushing test according to claim 1, characterized by The shape of the lifting seat flange (12) is oval or square.

3. The oil tank structure for converter transformer valve side bushing test according to claim 1, characterized by The oil tank side wall (1) is made of 12mm thick Q235B ordinary carbon steel plate, the manhole (6) is arranged at the lower left of the oil tank side wall (1) and the test oil tank body, and the triangular reinforcing plates (5) are uniformly arranged in the height direction.

4. The oil tank structure for converter transformer valve side bushing test according to claim 1, characterized by The grounding nut (10) is arranged on the outer side of the square cover plate (7) by welding, and the lifting lugs (11) are symmetrically arranged on the upper part of the square cover plate (7) by welding.

5. The oil tank structure for converter transformer valve side bushing test according to claim 1, characterized by The inner width and height of the test oil tank body are not less than 3300m and 4600mm respectively.

6. The oil tank structure for converter transformer valve side bushing test according to claim 1, characterized by The groove width and height of the sealing groove (13) are 13.4mm and 6.5mm respectively, the sealing groove (13) is matched with a rubber strip with a diameter of 10mm, 92 M16 threaded holes are uniformly processed on the method flange (2), and 12.9 grade bolts are matched.

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