A method and device for introducing cooling oil into a commutation flexible DC transformer

Abstract

The present invention relates to a method for introducing cooling oil into a flexible DC commutation transformer. A cooling oil introduction device is designed between the clamp oil guide pipe inside the transformer and the external cooling system. The cooling oil introduction device includes a metal support tube, an insulating tube, and a shielding ring. The insulating tube is sleeved around the outer periphery of the metal support tube. One end of the metal support tube and the insulating tube are connected to the clamp oil guide pipe, and the other end of the metal support tube and the insulating tube are connected to the external cooling system. The shielding ring is sleeved around the outer periphery of the insulating tube. The shielding ring is formed by integrally welding a T2Y copper plate and a T2M copper rod. The shielding ring is used to shield the end edges of the metal support tube to prevent discharge from high electric field areas to metal corners. The present invention also relates to a cooling oil introduction device for a flexible DC commutation transformer, including an insulating tube and a metal support tube. The metal support tube is welded integrally to the metal tube by a flange. The present invention has good integrity, a simple and reliable structure, and can be assembled independently.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformer production and manufacturing, and in particular relates to a transformer cooling oil introduction method and an introduction device with a shielding structure suitable for a commutation flexible DC transformer. Background Art

[0002] Due to their large capacity and stringent heat dissipation and temperature rise control requirements, flexible DC commutation transformers generally employ a strong oil-guiding structure. This structure requires a cooling oil inlet device to connect the transformer to the external cooling system. This cooling oil inlet device is located at the junction of the transformer's internal and external cooling systems, typically near the valve-side leads. The high electric field intensity places high demands on the insulation of the cooling oil inlet device, requiring effective shielding of nearby metal structures. If the distance from the valve-side leads is too close, effective electrical shielding cannot be achieved, resulting in failure of the sharp-angle discharge test of the leads to the metal structures. Furthermore, as an oil-guiding pipeline, the cooling oil inlet device must be sealed. If the sealing is poor, the transformer oil will not flow according to the guiding path under the oil pressure generated by the oil pump. In severe cases, this can damage the connecting device, reduce the cooling effect of the transformer body, and cause the temperature rise to exceed the limit. If it is designed as an integrated oil-guiding pipeline, this will affect the drop-out of the transformer body and the overall assembly of the transformer. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a method and device for introducing cooling oil into a commutation flexible DC transformer with a shielded structure. The technical solution adopted by the present invention is as follows:

[0004] A method for introducing cooling oil into a commutation flexible DC transformer comprises the following steps:

[0005] A cooling oil introduction device is designed between the clamp oil guide pipe inside the transformer and the external cooling system. The cooling oil introduction device includes a metal support pipe, an insulating pipe and a shielding ring. The insulating pipe is sleeved on the outer circumference of the metal support pipe. One end of the metal support pipe and the insulating pipe is connected to the clamp oil guide pipe, and the other end of the metal support pipe and the insulating pipe is connected to the external cooling system. A shielding ring is sleeved on the outer circumference of the insulating pipe; the shielding ring is formed by integrally welding a T2Y copper plate and a T2M copper rod. The shielding ring is used to shield the end edges of the metal support pipe to prevent discharge from high electric field areas to metal sharp corners.

[0006] A cooling oil introduction device for a commutation flexible DC transformer, applying the aforementioned introduction method, comprises: an insulating tube and a metal support tube, wherein the metal support tube is welded to the metal tube by a flange, the flange being located at one end of the metal tube, the insulating tube being sleeved on the outer periphery of the metal tube of the metal support tube, a fixed flange being sleeved on the outer periphery of the end of the insulating tube away from the flange of the metal support tube, the fixed flange being connected to the end flange by standard metal fasteners, the end flange being welded to the clamp oil guide tube, a sealing gasket being provided between the fixed flange and the end flange, and the flange of the metal support tube being mounted to the outer side of the oil tank wall by standard metal fasteners. A welding flange is provided on the outer side of the flange of the metal support tube, and the welding flange is welded to the outer side of the oil tank wall. The thickness of the welding flange is greater than the thickness of the flange of the metal support tube. The transition flange is installed on the outer side of the welding flange through standard metal fasteners. One end of the cooling oil connecting pipeline is integrally formed with an end flange plate, and the end flange plate of the cooling oil connecting pipeline is installed on the outer side of the transition flange through standard metal fasteners. A shielding ring is sleeved on the outer periphery of the insulating tube; a limiting structure is integrally formed on the side of the end flange away from the fixed flange, and the limiting structure is L-shaped, and the end of the limiting structure away from the end flange abuts against the insulating tube.

[0007] The beneficial effects of the present invention are:

[0008] The shielded cooling oil inlet device boasts excellent integrity, a simple and reliable structure, and can be assembled independently. It connects the internal and external parts of the converter transformer's oil-enhancing guide structure, effectively improving assembly efficiency while ensuring a certain seal on the oil-enhancing guide oil circuit. It also effectively shields metal parts in high-field strength areas, enhancing the reliability of the converter transformer's oil-enhancing guide structure and ensuring excellent assembly processability. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings described below are some specific embodiments of the present invention. For those of ordinary skill in the art, without inventive effort, other drawings within the scope of protection of this application can be derived from these drawings.

[0010] Figure 1 Schematic diagram of the structure and installation of a cooling oil introduction device according to an embodiment of the present invention;

[0011] Figure 2-1 、 2-2 1 is a front view and a side view of an end flange according to an embodiment of the present invention;

[0012] Figure 3 is a front view of a metal support tube according to an embodiment of the present invention;

[0013] Figure 4-1 、 4-2 1 is a front view and a side view of a welding flange according to an embodiment of the present invention;

[0014] Figure 5-1 、 5-2 1 is a front view and a side view of a transition flange according to an embodiment of the present invention;

[0015] Figure 6 is a front view of a cooling oil connecting pipeline according to an embodiment of the present invention;

[0016] Figure 7-1 、 7-2 1 is a front view and a side view of a shielding ring according to an embodiment of the present invention;

[0017] Figure 8 Schematic diagram of the installation and fixation of the shielding ring according to an embodiment of the present invention;

[0018] In the figure: 1 is the end flange, 2 is the sealing gasket, 3 is the fixed flange, 4 is the insulating tube, 5 is the shielding ring, 6 is the metal support tube, 7 is the welding flange, 8 is the transition flange, 9 is the cooling oil connecting pipeline, 10 is the clamp oil guide pipe, 11 is the oil tank wall, 12 is the limiting structure, 13 is the first wire hole, 14 is the end flange, 15 is the second wire hole, 16 is the third wire hole, 17 is the copper plate, 18 is the copper rod, 19 is the copper ring, 20 is the bolt, 21 is the first flat washer, 22 is the second flat washer, 23 is the spring washer, and 24 is the shielding cap. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, but not all of the embodiments.

[0020] A method for introducing cooling oil into a commutation flexible DC transformer comprises the following steps:

[0021] A cooling oil inlet device is designed between the transformer's internal clamp oil guide pipe and the external cooling system. The device comprises a metal support tube, an insulating tube, and a shielding ring. The insulating tube is sheathed around the outer circumference of the metal support tube. One end of the metal support tube and the insulating tube are connected to the clamp oil guide pipe, while the other ends of the metal support tube and the insulating tube are connected to the external cooling system. A shielding ring is sheathed around the outer circumference of the insulating tube. The shielding ring is formed by integrally welding a T2Y copper plate and a T2M copper rod. It shields the end edges of the metal support tube, preventing discharges from high electric field areas to metal corners. The shielding ring comprises a copper plate, a copper rod, and a copper ring. The copper ring is a copper rod machined into a coiled spring shape, with one end of the copper ring integrally formed with one end of the copper rod, and the other end of the copper rod connected to the copper plate.

[0022] like Figure 1Figure 1 shows the structure and installation diagram of a cooling oil introduction device according to an embodiment of the present invention. One end of the cooling oil introduction device is fixedly connected to a clamp oil guide pipe 10, while the other end is fixedly connected to the oil tank wall 11. This cooling oil introduction device can be assembled independently after the device body is placed in the tank.

[0023] A cooling oil introduction device for a commutation flexible DC transformer, applying the aforementioned cooling oil introduction method for a commutation flexible DC transformer, comprises: an insulating tube 4 and a metal support tube 6, wherein the insulating tube 4 is made of kraft pulp, the metal support tube 6 is welded into one piece by a flange, the flange being located at one end of the metal tube, the insulating tube 4 being sleeved on the outer periphery of the metal tube of the metal support tube 6, a fixed flange 3 being sleeved on the outer periphery of the end of the insulating tube 4 away from the flange of the metal support tube 6, the insulating tube 4 insulating the metal support tube 6, the fixed flange 3 being connected to the end flange 1 by standard metal fasteners, a sealing gasket 2 being arranged between the fixed flange 3 and the end flange 1, the diameter of the central opening of the sealing gasket 2 being slightly smaller than the outer diameter of the insulating tube 4, the sealing gasket 2 and the insulating tube 4 being interference fit, and the sealing gasket 2 being made of nitrile rubber.

[0024] like Figure 2-1 、 2-2 The figure shows the front view and side view of the end flange of the embodiment of the present invention. The side of the end flange 1 away from the fixed flange 3 is integrally formed with a limiting structure 12. The limiting structure 12 is L-shaped. The end of the limiting structure 12 away from the end flange 1 abuts against the insulating tube 4 to limit the horizontal displacement of the insulating tube 4. A first thread hole 13 is provided on the side of the end flange 1. The first thread hole 13 is used to connect the end flange 1 to the fixed flange 3 through standard metal fasteners. The end flange 1 is welded to the clamp oil guide pipe 10 as a whole, and the limiting structure 12 and the end of the insulating tube 4 are located in the clamp oil guide pipe 10.

[0025] The flange of the metal support tube 6 is mounted to the outside of the tank wall 11 using standard metal fasteners. A welding flange 7 is installed outside the flange of the metal support tube 6 and welded to the outside of the tank wall 11. The thickness of the welding flange 7 is greater than that of the flange of the metal support tube 6, providing space for assembly of the flange of the metal support tube 6. A transition flange 8 is mounted to the outside of the welding flange 7 using standard metal fasteners. The end flange 14 of the cooling oil connecting line 9 is also mounted to the outside of the transition flange 8 using standard metal fasteners. The transition flange 8 serves as a transition connection.

[0026] like Figure 3 The flange of the metal support tube 6 is provided with a long through hole, through which the flange of the metal support tube 6 is mounted on the outside of the tank wall 11 using standard metal fasteners.

[0027] like Figure 4-1 、 4-2 The figure shows the front view and side view of the welding flange of the embodiment of the present invention. A second thread hole 15 is provided at the edge of the welding flange 7, through which the transition flange 8 is mounted on the outside of the welding flange 7 using standard metal fasteners.

[0028] like Figure 5-1 、 5-2 The figures show front and side views of a transition flange according to an embodiment of the present invention. The transition flange 8 is an integrally formed square base plate with a circular hole and an annular boss. Mounting holes are provided on the edge of the square base plate, matching the second through-holes 15. The mounting holes and second through-holes 15 allow the transition flange 8 to be mounted on the outside of the welding flange 7. A third through-hole 16 is provided on the annular boss, through which the end flange 14 of the cooling oil connecting line 9 is mounted on the outside of the transition flange 8 using standard metal fasteners.

[0029] like Figure 6 The figure shows a front view of a cooling oil connecting pipe according to an embodiment of the present invention. Cooling oil connecting pipe 9 is the cooling oil outlet pipe of the transformer's external cooling system and serves as the connecting pipe for cooling oil to enter the transformer body. One end of cooling oil connecting pipe 9 is integrally formed with an end flange 14 that mates with transition flange 8.

[0030] A shielding ring 5 is sleeved around the outer periphery of the insulating tube 4. The shielding ring 5 is used to shield the edge of the metal tube end of the metal support tube 6 to prevent discharge from the high electric field area to the metal corner. The shielding ring 5 is formed by welding T2Y copper plate and T2M copper rod into one piece. The shielding ring 5 includes: copper plate 17, copper rod 18 and copper ring 19. Figure 7-1 、 7-2 Figures 2 and 3 show front and side views of a shielding ring according to an embodiment of the present invention. The copper ring 19 is a copper rod machined into a coil spring shape. One end of the copper ring 19 is integrally formed with one end of the copper rod 18. The other end of the copper rod 18 is connected to a copper plate 17, which secures the shielding ring 5 to the inner wall of the fuel tank wall 11.

[0031] like Figure 8 Figure 1 shows a schematic diagram of the installation and fixation of a shielding ring according to an embodiment of the present invention. A mounting hole is defined on the end of copper plate 17 facing away from copper rod 18. Bolts 20 pass through the mounting hole and are screwed into mounting holes on the inner wall of tank wall 11. A first flat washer 21 and a second flat washer 22 are positioned on either side of copper plate 17, with the first flat washer 21 positioned adjacent to the bolt head of bolt 20. A spring washer 23 is positioned between the first flat washer 21 and the bolt head of bolt 20. A shielding cap 24 is positioned over the bolt head of bolt 20 for shielding protection. The mounting position of copper plate 17 aligns with the metal support tube 6.

[0032] In this embodiment of the present invention, the end flange 1, fixed flange 3, metal support tube 6, welding flange 7, transition flange 8, and retaining structure 12 are made of Q355 high-strength alloy steel. The standard metal fasteners include bolts, nuts, flat washers, and spring washers. The shielding cap and standard metal fasteners are all blackened. The cooling oil connecting line 9 and the end flange 14 are both made of Q235 ordinary carbon steel. The fastening opening of the fixed flange 3 is depainted and connected to the clamp oil guide pipe 10 at the same potential via standard metal fasteners.

[0033] Remove paint from the fastening holes of the fixed flange 1 and ensure they are at the same potential as the clamping oil guide tube 10. Standard metal fasteners require a blackening treatment. During assembly, allow a certain length for the insulating tube 4. After trial assembly, adjust the length of the insulating tube 4 by cutting it so that the end face of the insulating tube 4 is in close contact with the retaining structure 12 of the end flange 1.

[0034] Finally, it should be noted that the above embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them, and the protection scope of the present invention is not limited thereto. 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 described in the above embodiments within the technical scope disclosed by the present invention, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for introducing cooling oil into a commutation flexible DC transformer, applied to a cooling oil introduction device, characterized in that: The following steps are involved: A cooling oil introduction device is designed between the clamp oil guide pipe (10) inside the transformer and the external cooling system. The cooling oil introduction device includes a metal support pipe (6), an insulating pipe (4) and a shielding ring (5). The metal support pipe (6) is welded to the metal pipe by a flange. The flange is located at one end of the metal pipe. The insulating pipe (4) is sleeved on the outer periphery of the metal support pipe (6). One end of the metal support pipe (6) and the insulating pipe (4) are connected to the clamp oil guide pipe (10). The other end of the metal support pipe (6) and the insulating pipe (4) are connected to the metal support pipe (6). An external cooling system is provided, wherein a shielding ring (5) is sleeved on the outer periphery of the insulating tube (4); the shielding ring (5) comprises a copper plate (17), a copper rod (18) and a copper ring (19), and is formed by welding the copper plate (17) and the copper rod (18) into one piece; the copper ring (19) is a copper rod processed into a spiral spring shape; one end of the copper ring (19) is formed into one piece with one end of the copper rod (18), and the other end of the copper rod (18) is connected to the copper plate (17); the shielding ring (5) is used to shield the end edge of the metal support tube (6) to prevent discharge from the high electric field area to the metal sharp corner; A fixed flange (3) is sleeved on the outer periphery of one end of the flange of the insulating tube (4) away from the metal support tube (6); the fixed flange (3) and the end flange (1) are connected by standard metal fasteners; the end flange (1) and the clamp oil guide tube (10) are welded into one body; a sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the flange of the metal support tube (6) is installed on the outer side of the oil tank wall (11) by standard metal fasteners; a welding flange (7) is arranged on the outer side of the flange of the metal support tube (6); the welding flange (7) is welded to the outer side of the oil tank wall (11); the welding flange (7) is welded to the outer side of the oil tank wall (11); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); the sealing gasket (2) is arranged between the fixed flange (3) and the end flange (1); ... The thickness is greater than the flange thickness of the metal support pipe (6), the transition flange (8) is installed on the outside of the welding flange (7) through standard metal fasteners, one end of the cooling oil connecting pipe (9) is integrally formed with an end flange (14), and the end flange (14) of the cooling oil connecting pipe (9) is installed on the outside of the transition flange (8) through standard metal fasteners; the side of the end flange (1) away from the fixed flange (3) is integrally formed with a limiting structure (12), the limiting structure (12) is L-shaped, and the end of the limiting structure (12) away from the end flange (1) is in contact with the insulating pipe (4).

2. The method for introducing cooling oil into a commutation flexible DC transformer according to claim 1, characterized in that: A mounting through hole is provided at one end of the copper plate (17) away from the copper rod (18), and a bolt (20) is screwed into the mounting thread hole on the inner wall of the oil tank wall (11) through the mounting through hole. A first flat washer (21) and a second flat washer (22) are respectively provided on both sides of the copper plate (17), the first flat washer (21) is close to the bolt head of the bolt (20), a spring washer (23) is provided between the first flat washer (21) and the bolt head of the bolt (20), a shielding cap (24) is provided on the bolt head of the bolt (20), and the mounting position of the copper plate (17) matches the metal support tube (6).

3. The method for introducing cooling oil into a commutation flexible DC transformer according to claim 1, characterized in that: A first thread hole (13) is provided on the side of the end flange (1); the insulating tube (4) is made of sulfate pulp; the diameter of the central opening of the sealing gasket (2) is slightly smaller than the outer diameter of the insulating tube (4); the sealing gasket (2) and the insulating tube (4) are interference fit; and the sealing gasket (2) is made of nitrile rubber.

4. The method for introducing cooling oil into a commutation flexible DC transformer according to claim 1, characterized in that: The metal support tube (6) is provided with a long through hole, and a second thread hole (15) is provided at the edge of the welding flange (7).

5. The method for introducing cooling oil into a commutation flexible DC transformer according to claim 4, characterized in that: The transition flange (8) is an integrally formed square bottom plate with a circular hole and an annular boss. The edge of the square bottom plate is provided with a mounting hole matched with the second thread hole (15), and the annular boss is provided with a third thread hole (16).

6. The method for introducing cooling oil into a commutation flexible DC transformer according to claim 2, characterized in that: The standard metal fasteners are bolts, nuts, flat washers and spring washers. The shielding cap (24) and the standard metal fasteners all need to be blackened.

7. The method for introducing cooling oil into a commutation flexible DC transformer according to claim 6, characterized in that: The end flange (1), fixed flange (3), metal support pipe (6), welding flange (7), transition flange (8) and limiting structure (12) are made of high-strength alloy steel; the cooling oil connecting pipeline (9) and the end flange (14) are made of ordinary carbon steel; the fastening position opening of the fixed flange (3) is paint-free and is connected to the same potential as the clamp oil guide pipe (10) through standard metal fasteners.

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