A lead shielding tube structure with good heat dissipation function

Abstract

The present invention belongs to the field of power transformer manufacturing, and specifically is a lead shielding tube structure with good heat dissipation function. It includes: a long support bar assembly, a support tube, an insulating tube, an outer insulation layer, and an oil drain hole opened on the lead shielding tube; wherein, the hole wall of the oil drain hole is coated with an insulating layer; a support tube is sleeved on the shielding tube; the support tube includes: a cylindrical section and a conical tube section connected thereto as a whole; the cylindrical section of the support tube is sleeved on the lead shielding tube at the oil drain hole, and an insulating tube is provided between the conical tube section of the support tube and the lead shielding tube; the insulating tube is adapted to the conical tube section of the support tube; a long support bar assembly is sandwiched between the insulating tube and the support tube; the outer insulation layer is coated on the lead shielding tube, and the thickness of the outer insulation layer is equal to the outer diameter of the conical tube section of the support tube. The present invention solves the contradiction between insulation performance and heat dissipation performance in the previous lead shielding tube structure by arranging an oil drain hole with a long support bar assembly and cooperating with the insulating tube.

Description

Technical Field

[0001] The invention belongs to the field of power transformer manufacturing, in particular to a lead shielding tube structure with good heat dissipation function. Background Art

[0002] Lead shielding tube is an essential component for the uniformity of the lead electric field of UHV transformers. Its insulation performance and heat dissipation performance directly affect the safe and reliable operation of transformers and even power grids. With the rapid development of UHV power grid technology, the rated capacity and voltage level of AC and DC transformers used in power grids are constantly increasing, which puts forward higher and higher requirements on the insulation performance and heat dissipation performance of transformer lead shielding tubes. The increase in the voltage level of the transformer directly determines the improvement of the insulation level of the lead shielding tube; with the increase in transformer capacity, on the one hand, the increase in lead current directly leads to the increase in lead cable loss in the shielding tube, and on the other hand, the increase in leakage magnetic field at the end of the transformer winding causes a sharp increase in the eddy current loss of the shielding tube itself. The loss of the lead cable in the shielding tube and the eddy current loss of the shielding tube itself are dissipated in the form of heat energy, which is easy to cause local overheating in large-capacity transformers. Usually, in terms of structure, there is a contradictory relationship between the insulation performance and heat dissipation performance of the shielding tube. In order to improve the insulation performance, it is necessary to increase the thickness of the outer insulation layer of the shielding tube, and the increase in the thickness of the insulation layer will lead to a decrease in heat dissipation capacity. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a lead shielding tube structure with good heat dissipation function, so as to solve the contradiction between insulation and heat dissipation, which is very likely to cause local overheating of the lead when the transformer capacity is too large due to the difficulty in oil flow. It can ensure that the lead shielding tube of high-voltage transformer has sufficient insulation performance and good heat dissipation function, thus avoiding the risk of local overheating of the lead shielding tube of large-capacity transformer.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0005] A lead shielding tube structure with good heat dissipation function, comprising: a long support bar assembly, a support tube, an insulating tube, an outer insulating layer, and an oil drain hole opened on the lead shielding tube;

[0006] Wherein, an insulating layer is coated on the hole wall of the oil drain hole; a supporting tube is sleeved on the lead shielding tube at the oil drain hole;

[0007] The support cylinder comprises: a cylindrical section and a conical cylinder section connected as one body;

[0008] The cylindrical section of the support tube is sleeved on the lead shielding tube at the oil drain hole, and an insulating tube is arranged between the conical tube section of the support tube and the lead shielding tube; the insulating tube is adapted to the conical tube section of the support tube;

[0009] A long support bar assembly is sandwiched between the insulating tube and the supporting tube; the outer insulation layer is coated on the lead shielding tube.

[0010] The insulating cylinder is a solid conical cylinder structure covered by stacked insulating crepe paper.

[0011] The insulating tube is sleeved on the lead shielding tube on both sides or any one side of the oil drain hole.

[0012] The long support bar assembly comprises: a plurality of long support bars evenly arranged along the circumference of the lead shielding tube; a crenel structure for the long support bars to bend is provided on the long support bars; the long support bars on one side of the crenel structure are oil channel support bars, and the long support bars on the other side of the crenel structure are insulating support bars;

[0013] The oil channel support bar is arranged between the cylindrical section of the support tube and the lead wire shielding tube at the oil drain hole, and an upper notch is provided on the oil channel support bar; a slot for oil flow from the oil drain hole is provided on the upper notch, and the direction of the slot is opposite to the oil drain hole;

[0014] The insulating support bar is arranged between the insulating cylinder and the conical cylinder section of the supporting cylinder, and is bonded to the outer surface of the insulating cylinder.

[0015] A plurality of notches are arranged in parallel on the upper recess, and the corresponding notches on two adjacent upper recesses are connected end to end to form a circular annular groove on the oil drain hole; the width of the notch is less than 30 mm.

[0016] There are multiple oil drain holes, and each of the oil drain holes is an oblong hole with rounded corners; the width of each oil drain hole is greater than 10 mm, and the length of each oil drain hole is greater than 30 mm.

[0017] A plurality of short struts are evenly arranged between the conical tube of the support tube and the outer insulation layer to prevent the outer insulation layer from collapsing, and the short struts are fixed on the conical tube surface of the support tube between two adjacent long struts; the short struts are parallel to the long struts.

[0018] The insulating layer is insulating paper, and the insulating layer covers the hole wall of the oil drain hole;

[0019] One end of the insulating layer extends out of the oil drain hole and is attached to the inner wall of the lead shielding tube, and the other end extends into the oil drain hole and is attached to the outer wall of the lead shielding tube;

[0020] The thickness of the insulating layer is 1 mm to 2 mm, and the length of the insulating layer extending to the inner wall and the outer wall of the lead shielding tube is greater than 10 mm.

[0021] The thickness of the outer insulation layer is the distance between the outer wall of the lead shielding tube and the end of the corresponding conical tube section of the support tube.

[0022] The present invention has the following beneficial effects and advantages:

[0023] 1. The present invention solves the contradiction between insulation performance and heat dissipation performance in the previous lead shielding tube structure by arranging an oil drain hole with a long support bar assembly and cooperating with the insulation tube;

[0024] 2. The lead shielding tube of the present invention has sufficient electrical strength through the rounded corner treatment of the oil drain holes and the surface insulation covering. The oil drain holes, insulating struts and their notches form internal and external oil circulation channels to conveniently discharge the heat generated by the eddy current loss of the lead cable and the shielding tube itself, so that it has good heat dissipation performance, which expands the space for the development of ultra-high voltage and ultra-large capacity transformers.

[0025] 3. The new type of lead shielding tube adopted by the present invention has a simple structure, low manufacturing cost and convenient installation, thereby achieving the effect of improving product performance and reducing product cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1a This is a schematic diagram of an "n"-shaped lead shielding tube of the present invention;

[0027] Figure 1b This is a schematic diagram of the "J"-shaped shielding tube of the present invention;

[0028] Figure 2 It is a schematic longitudinal section diagram of the lead shielding tube of the present invention;

[0029] Figure 3 This is a cross-sectional view of an opening of the lead shielding tube of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the insulating tube of the lead shielding tube of the present invention;

[0031] Figure 5 This is a partial enlarged view of the insulation layer of the lead shielding tube of the present invention;

[0032] Figure 6 This is a schematic diagram of the overall structure of the lead shielding tube of the present invention;

[0033] Figure 7 It is a schematic diagram of a long support bar assembly in a lead shielding tube of the present invention;

[0034] Figure 8 This is a schematic diagram of the support tube structure in the lead shielding tube of the present invention;

[0035] Among them, 1 is the lead shielding tube, 2 is the oil drain hole, 3 is the insulating layer, 4 is the insulating tube, 5 is the long support bar, 6 is the crenel structure, 7 is the upper notch, 8 is the short support bar, 9 is the supporting tube, 10 is the outer insulation, 11 is the oil channel support bar, 12 is the insulating support bar, and 13 is the notch. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0037] like Figure 1a and Figure 1b As shown, it is a schematic diagram of the "n" and "few" shaped lead shielding tubes of the present invention; the lead shielding tube 1 is a shielding tube made of a conductor material with an oil drainage hole 2.

[0038] The present invention comprises: a lead shielding tube 1 with an oil drain hole 2, an insulating layer 3, an insulating tube 4, a long support bar 5 with a crenel structure 6 and an upper notch 7, a short support bar 8, a support tube 9, and an outer insulating layer 10;

[0039] The wall of the oil drain hole 2 is covered with an insulating layer 3; the inner and outer peripheries of the oil drain hole 2 are rounded and covered with a 1 to 2 mm thick insulating layer 3 to meet the insulation performance requirements. The width of the oblong hole before covering with insulation should be no less than 10 mm and the length should be no less than 30 mm to meet the oil flow heat dissipation requirements.

[0040] like Figure 8 As shown, it is a schematic diagram of the support tube structure of the present invention. In order to prevent the outer insulation 10 from collapsing, a support tube 9 is sleeved on the long support bar 5; the support tube 9 includes: a cylindrical section and a conical cylinder section connected thereto as an integral body; the cylindrical section of the support tube 9 is sleeved on the lead shielding tube 1 at the oil drain hole 2, and an insulating tube 4 is provided between the conical cylinder section of the support tube 9 and the lead shielding tube 1; the insulating tube 4 is adapted to the conical cylinder section of the support tube 9; a long support bar assembly is sandwiched between the insulating tube 4 and the support tube 9;

[0041] like Figures 2-3 As shown, it is a schematic diagram of the opening of the lead shielding tube of the present invention, that is, a cross-sectional view: there are multiple oil drain holes 2, the width of the oil drain hole 2 is greater than 10mm, and the length should be greater than 30mm. In this embodiment, three oil drain holes 2 are processed above the installation direction of the lead shielding tube 1, and the actual number, size and specific position of the oil drain holes 2 can be determined according to the requirements of the heat dissipation oil flow. The inner and outer peripheries of the oil drain holes 2 processed on the lead shielding tube 1 are required to be rounded, and the oil drain holes are in the structure of oblong holes.

[0042] like Figure 4 As shown, it is a schematic diagram of the insulating tube structure of the lead shielding tube of the present invention. The oil drain hole 2 processed on the lead shielding tube 1 is covered with insulating corrugated paper to form an insulating layer 3, and then the left and right sides (or both sides) of the oil drain hole 2 are covered with insulating paper to form a tight solid conical insulating tube 4.

[0043] The length of the insulating tube 4 should be greater than 5 times the total thickness of the outer insulation 10 of the lead shielding tube 1 to meet the creepage strength of the insulation along the oil channel support 11 after adding the oil drain hole 2, and to ensure that the insulation performance of the lead shielding tube 1 after adding the oil drain hole 2 is not reduced.

[0044] like Figure 5 As shown, it is a partial enlarged view of the insulation layer of the lead shielding tube of the present invention. The thickness of the insulation layer 3 is 1mm to 2mm, and the length extending into the inner wall of the hole is greater than 10mm to ensure the insulation performance.

[0045] like Figures 6-7 The figure shows the overall structure of the lead shielding tube of the present invention. The long support bar 5 can be a two-section structure, or a crenel structure 6 can be cut out of the entire long support bar 5 to facilitate the bending of the support bar and prevent it from falling over, so that the oil flow inside the shielding tube can also flow in the circumferential direction to improve the cooling effect. The total width of the notch 13 should be greater than the width of the oblong hole. Multiple notches 13 can be set, and the width of a single notch 13 is not greater than 30 mm to prevent the support bar from collapsing when wrapping the external insulation. In this embodiment, a long support bar assembly 5 with a chop structure 6 and a short support bar 8 are placed radially in the circumferential direction on the outside of the conical structure insulation 4 on the lead shielding tube 1.

[0046] One side of the crenel structure 6 is an oil channel support bar 11, and the other side of the crenel structure 6 is an insulating support bar 13;

[0047] The oil channel support bar 11 is arranged between the cylindrical section of the support tube 9 and the oil drain hole 2, and an upper notch 7 is opened on the oil channel support bar 11; a groove 13 for oil flow from the oil drain hole 2 is opened on the upper notch 7; the insulating support bar 13 is clamped between the insulating tube 4 and the conical tube section of the support tube 9, that is: the long support bar 5 is placed from the cylindrical tube section of the support tube 9 pre-wrapped outside the lead shielding tube 1 to the end of the conical tube section of the support tube 9.

[0048] A plurality of notches are arranged in parallel on the upper recess 7 , and the corresponding notches on two adjacent upper notches 7 are connected end to end to form an annular groove above the oil drain hole 2 , and the width of the notch is less than 30 mm.

[0049] A plurality of short struts 8 are evenly arranged between the conical tube of the support tube 9 and the outer insulation 10 to prevent the outer insulation 10 from collapsing, and the short struts 8 are arranged on the support tube above the two adjacent long struts 5. The long struts 5 and the short struts 8 are both bonded to the conical insulation surface with epoxy resin glue having excellent insulation performance. The upper notch 7 should be placed toward the lead shielding tube 1 to facilitate the oil flow, and the crenel structure 6 processed on the long struts 5 is convenient for bending. After the long struts 5 and the short struts 8 are placed, the outer side is covered with insulating crepe paper to form the outer insulation 10 of the lead shielding tube.

[0050] Embodiment 1: This embodiment adopts an existing lead shielding tube 1, which has an outer diameter of 130 mm and a wall thickness of 4 mm; three oil drain holes 2 with a width of 10 mm and a length of 30 mm are provided in the lead shielding tube 1; the thickness of the insulating layer 3 is 2 mm, and the length of the insulating layer 3 extending into the inner wall of the lead shielding tube 1 is 12 mm, and the length of the insulating layer 3 extending out of the lead shielding tube 1 and attached to the outer wall of the lead shielding tube 1 is 12 mm. The maximum thickness of the insulating tube 4 is 120 mm (excluding the outer diameter of the lead shielding tube 1), and the total length of the insulating tube 4 is 350 mm;

[0051] Twelve long stays 5 and twelve short stays 8 are evenly arranged along the circumferential direction, two notches are set in the upper notch 7 of each long stay 5, and the width of each notch is 10 mm, forming an annular groove on the lead shielding tube 1;

[0052] Insulating corrugated paper is stacked and covered on the lead shielding tube 1, the support tube 9 and the short support bar to form an outer insulation 10, and the thickness of the outer insulation 10 is 60 mm. The application effect is compared with the existing lead shielding tube structure, and the comparison is shown in Table 1 below:

[0053] Table 1

[0054]

[0055] It can be seen from Table 1 that the present invention forms an internal and external oil circulation channel by setting the oil drain hole 2, the long support bar 5 and its notch to conveniently discharge the heat generated by the eddy current loss of the lead cable and the lead shielding tube 1 itself. Compared with the existing lead shielding tube structure, the present invention has good heat dissipation performance; at the same time, the setting of the support tube 9 and the short support bar 8 effectively prevents the collapse of the external insulation 10 when the temperature is too high. Conclusion: The present invention solves the contradiction between the insulation performance and the heat dissipation performance in the existing lead shielding tube structure through the cooperation of the long support bar assembly, the oil drain hole 2 and the insulation tube 4.

Claims

1. A lead shielding tube structure with good heat dissipation function, characterized in that: include: A long support bar assembly, a support tube (9), an insulating tube (4), an outer insulating layer (10), and an oil drain hole (2) provided on the lead shielding tube (1); Wherein, the hole wall of the oil drain hole (2) is covered with an insulating layer (3); and a support tube (9) is sleeved on the lead shielding tube (1) at the oil drain hole (2); The support cylinder (9) comprises: a cylindrical section and a conical cylinder section connected as one body; The cylindrical section of the support tube (9) is sleeved on the lead wire shielding tube (1) at the oil drain hole (2), and an insulating tube (4) is provided between the conical tube section of the support tube (9) and the lead wire shielding tube (1); the insulating tube (4) is adapted to the conical tube section of the support tube (9); A long support bar assembly is sandwiched between the insulating tube (4) and the supporting tube (9); the outer insulation layer (10) is coated on the lead shielding tube (1); The long support bar assembly comprises: a plurality of long support bars (5) uniformly arranged along the circumference of the lead shielding tube (1); a crenel structure (6) for the long support bars (5) to bend is provided on the long support bars (5); the long support bars (5) on one side of the crenel structure (6) are oil channel support bars (11), and the long support bars (5) on the other side of the crenel structure (6) are insulating support bars (12); The oil channel support bar (11) is arranged between the cylindrical section of the support tube (9) and the lead shielding tube (1) at the oil drain hole (2), and an upper notch (7) is provided on the oil channel support bar (11); a slot (13) for oil flow from the oil drain hole (2) is provided on the upper notch (7), and the direction of the slot (13) is opposite to the oil drain hole (2); The insulating support bar (12) is arranged between the insulating tube (4) and the conical tube section of the supporting tube (9), and is bonded to the outer surface of the insulating tube (4); The length of the insulating tube (4) is greater than 5 times the total thickness of the lead shielding tube (1) and the outer insulation (10), so as to meet the creepage strength of the insulation along the direction of the oil channel support bar (11) after the oil drain hole (2) is added, and ensure that the insulation performance of the lead shielding tube (1) is not reduced after the oil drain hole (2) is added.

2. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: The insulating cylinder (4) is a solid conical cylinder structure covered by stacked insulating corrugated paper.

3. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: The insulating tube (4) is sleeved on the lead shielding tube (1) on both sides or any one side of the oil drain hole (2).

4. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: A plurality of notches (13) are arranged in parallel on the upper notch (7), and the corresponding notches (13) on two adjacent upper notches (7) are connected end to end to form an annular groove on the oil drain hole (2); the width of the notch is less than 30 mm.

5. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: The oil drain hole (2) is provided with a plurality of holes, and the oil drain hole (2) is an oblong hole with rounded corners; the width of the oil drain hole (2) is greater than 10 mm, and the length of the oil drain hole (2) is greater than 30 mm.

6. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: A plurality of short struts (8) are evenly arranged between the conical tube of the support tube (9) and the outer insulation (10) to prevent the outer insulation (10) from collapsing, and the short struts (8) are fixed on the conical tube surface of the support tube (9) between two adjacent long struts (5); the short struts (8) and the long struts (5) are parallel to each other.

7. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: The insulating layer (3) is insulating paper, and the insulating layer (3) covers the hole wall of the oil drain hole (2); One end of the insulating layer (3) extends out of the oil drain hole (2) and is attached to the inner wall of the lead wire shielding tube (1), and the other end extends into the oil drain hole (2) and is attached to the outer wall of the lead wire shielding tube (1); The thickness of the insulating layer (3) is 1 mm to 2 mm, and the length of the insulating layer (3) extending to the inner wall of the lead shielding tube (1) and the outer wall of the lead shielding tube (1) is greater than 10 mm.

8. The lead shielding tube structure with good heat dissipation function according to claim 1, characterized in that: The thickness of the outer insulation layer (10) is the distance between the outer wall of the lead shielding tube (1) and the end of the conical tube section of the corresponding support tube (9).

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