Converter transformer DC bushing with wall-through protection function

Abstract

The utility model relates to a converter transformer direct current bushing with a through-wall protection function, which comprises a direct current bushing and a protective sleeve assembly, the protective sleeve assembly penetrates through a firewall body and comprises a through-wall flange sleeve and a shielding cylinder sleeved on the outer side of the through-wall flange sleeve, a fireproof layer is arranged between the through-wall flange sleeve and the shielding cylinder, and the shielding cylinder is sleeved on the outer side of the through-wall flange sleeve. The direct current bushing comprises a main insulation sleeve and a bushing plugging part, the main insulation sleeve and the bushing plugging part are connected through a wall-through flange sleeve, the lower end of the main insulation sleeve is provided with a voltage-sharing shielding protective cover which completely covers the corresponding end part of the protective sleeve assembly, and the voltage-sharing shielding protective cover is grounded. A conductive tube and an inner insulation capacitor core body are arranged in the direct current sleeve, the inner insulation capacitor core body is sleeved on the conductive tube, and insulation gas is filled between the inner insulation capacitor core body and the outer insulation sleeve and between the inner insulation capacitor core body and the wall-penetrating flange sleeve. According to the utility model, the flame-retardant and explosion-proof requirements can be met, and the requirements of strong magnetic overheating prevention, partial discharge prevention and the like can also be met.

Description

Technical Field

[0001] The utility model relates to the field of converter transformers, in particular to a converter transformer DC bushing with a wall penetration protection function. Background Art

[0002] For large-scale power grid projects, the safe operation of DC converter stations and the equipment within the stations has a significant impact on the normal operation of the power grid, and the valve-side DC bushing of the converter transformer is an important component of the DC converter station. On the one hand, as an important insulating current-carrying component, the valve-side DC bushing not only has to carry thousands of amperes of current energy, but also has to withstand the influence of complex operating factors such as AC and DC composite voltages, various overvoltages, and strong electromagnetic fields in the operating environment. On the other hand, the valve-side DC bushing is a transition component connecting the internal and external equipment of the valve hall. Once it fails, or the converter transformer connected to the valve-side DC bushing fails, the problem will most likely spread to the inside of the valve hall, thereby causing more serious accidents. In order to avoid the risk of the fault spreading to the inside of the valve hall, some protective structures for the DC bushing of the converter transformer have also appeared in the existing technology.

[0003] For example, patent publication number CN109538834A discloses a fireproof structure and explosion-proof assembly for a converter transformer bushing. The fireproof component is installed between the converter transformer bushing and the wall, effectively sealing the gap between the bushing and the wall and preventing fire from spreading from the gap to the valve hall. A first explosion-proof assembly is installed between the bushing and the wall, with the first explosion-proof assembly positioned on the side of the fireproof component facing the bushing, effectively offsetting the explosive force of chemical explosions. However, this structure only addresses fire and explosion protection requirements. However, in actual use, it has been found that because the valve hall of a converter station operates in a strong electromagnetic field and high current environment, and most of the main structure of the valve-side bushing is located inside the valve hall, the valve-side bushing is at risk of overheating due to eddy currents in strong magnetic fields, or of generating localized discharge corona or even discharge due to excessive local discharge intensity in strong electric fields. Therefore, converter transformer DC bushings also require special requirements for protection against strong magnetic overheating and local discharge.

[0004] Patent publication number CN102829251A discloses a converter transformer bushing wall penetration sealing structure, which utilizes a silicone rubber sleeve inside the valve hall and a silicone rubber sleeve outside the valve hall to be connected and inserted into the wall penetration hole, thereby achieving the purpose of wrapping and sealing the wall penetration portion of the bushing. However, this structure mainly considers the requirement of easy installation, and does not take into account the special requirements of the converter transformer DC bushing such as protection against strong magnetic overheating and partial discharge.

[0005] Patent publication number CN113436838A discloses a novel converter transformer valve-side bushing protection device, which includes a fireproof tube, and the fireproof tube has two leaves, one of which is installed below the converter transformer valve-side bushing, and the other is installed above the converter transformer valve-side bushing. Flame retardant is filled between the two fireproof tubes and the converter transformer valve-side bushing. The beneficial effect of this structure is that it prevents the flame outside the valve hall without affecting the electric field strength of the valve-side bushing. However, this structure also does not take into account the special requirements of the converter transformer DC bushing, such as protection against strong magnetic overheating and partial discharge. Utility Model Content

[0006] The purpose of the utility model is to provide a converter transformer DC bushing with a wall penetration protection function, which can meet the requirements of flame retardancy and explosion prevention, as well as the requirements of protection against strong magnetic overheating and partial discharge.

[0007] The purpose of this utility model is achieved through the following technical solutions:

[0008] A DC bushing for a converter transformer with a wall-penetrating protection function comprises a DC bushing and a protective sleeve assembly, wherein the protective sleeve assembly passes through a fire wall, and the protective sleeve assembly comprises a wall-penetrating flange sleeve and a shielding cylinder sleeved on the outside of the wall-penetrating flange sleeve, a fireproof layer is provided between the wall-penetrating flange sleeve and the shielding cylinder, the DC bushing comprises an outer insulating sleeve and a sleeve plug-in portion, and the outer insulating sleeve and the sleeve plug-in portion are connected via the wall-penetrating flange sleeve, a voltage-equalizing shielding protective cover is provided at the lower end of the outer insulating sleeve for completely covering the corresponding ends of the protective sleeve assembly, and the voltage-equalizing shielding protective cover is grounded.

[0009] Fireproof baffles are provided inside both ends of the shielding tube, and the fireproof layer is provided between the two fireproof baffles.

[0010] A polyester material layer is provided between the fireproof layer and the shielding tube.

[0011] A lower connecting flange is provided at the lower end of the wall-penetrating flange sleeve, a mounting flange is provided at the upper end of the sleeve plug-in portion, and the lower connecting flange and the mounting flange are fixedly connected by fastening bolts, and sealant is provided between the outer side of the connection between the lower connecting flange and the mounting flange and the shielding tube.

[0012] An upper connecting flange is provided at the upper end of the wall-penetrating flange sleeve, an outer insulating sleeve flange is provided at the lower end of the outer insulating sleeve, a protective cover flange is provided inside the pressure-equalizing shielding protective cover, and the upper connecting flange, the outer insulating sleeve flange and the protective cover flange are fixedly connected by fastening bolts.

[0013] A bending baffle is provided at the upper end of the shielding cylinder, and the bending baffle is fixedly connected to the upper connecting flange. A sealing adhesive layer is provided between the outer insulating sleeve flange, the upper connecting flange and the bending baffle.

[0014] A conductive tube and an inner insulating capacitor core are provided inside the DC bushing, and the inner insulating capacitor core is sleeved on the conductive tube. Insulating gas is filled between the inner insulating capacitor core, the outer insulating sleeve and the wall flange sleeve.

[0015] The pressure-equalizing shielding protective cover is an ellipsoidal spherical structure and fits closely with the firewall.

[0016] The advantages and positive effects of this utility model are:

[0017] 1. The voltage-equalizing shielding protective cover and shielding tube and other structures of the present invention are made of non-magnetic metal materials, which can achieve complete electromagnetic shielding and zero-loop grounding effect for all metal parts passing through the firewall. Therefore, the present invention can effectively avoid the overheating of metal parts caused by eddy currents and circulating current losses in the leakage magnetic field, and at the same time can shield the strong electric field inside the valve hall to effectively avoid the risks of local discharge and local overheating of the casing's own structural components caused by strong electromagnetic field interference, strong current, etc.

[0018] 2. The protective sleeve assembly of the present invention includes a fireproof layer arranged between the wall-penetrating flange sleeve and the shielding tube, and the two ends of the fireproof layer are limited by fireproof baffles and are wrapped and compacted by a polyester material layer. The above structure can achieve radial flame retardant and axial flame retardant effects, and can also fully ensure the sealing performance of the fireproof layer.

[0019] 3. A sealant is provided at the connection between the lower end of the through-wall flange sleeve of the utility model and the sleeve plug-in part of the DC bushing, and a sealant layer is provided at the connection between the upper end of the through-wall flange sleeve and the outer insulating sleeve of the DC bushing. This enables a seamless flame-retardant and explosion-proof structure to be formed between the protective sleeve assembly and the DC bushing. At the same time, each flange adopts a fastening bolt to achieve a single-point short-circuit effect, which can further avoid the circulation loss caused by leakage magnetic induction between components, causing heat and causing overheating discharge and even fire failure.

[0020] 4. The capacitor core inside the DC bushing of the utility model is made of epoxy resin-impregnated paper, and the space between the capacitor core and the outer insulating sleeve and the wall flange sleeve is filled with insulating gas, thereby realizing an oil-free design of the bushing itself. This not only effectively improves the insulation strength and safe operation margin of the DC bushing itself, but also prevents fire and the expansion of problems when serious faults such as explosion and fire occur in the converter transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the use state of the utility model.

[0022] Figure 2 for Figure 1 An enlarged schematic diagram of the protective sleeve assembly.

[0023] Among them, 1 is a DC bushing, 101 is an outer insulating sleeve, 1011 is an outer insulating sleeve flange, 102 is a bushing plug-in part, 1021 is a mounting flange, 103 is a conductive tube, 104 is an inner insulating capacitor core, 105 is insulating gas, 2 is the inner area of ​​the valve hall, 3 is a fire wall body, 4 is a converter transformer, 5 is a protective sleeve assembly, 501 is a wall-penetrating flange sleeve, 5011 is an upper connecting flange, 5012 is a lower connecting flange, 502 is a fireproof layer, 503 is a polyester material layer, 504 is a shielding tube, 5041 is a bent baffle, 505 is a fireproof baffle, 506 is a sealant, 507 is a sealant layer, 6 is a pressure-equalizing shielding protective cover, and 601 is a protective cover flange. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] like Figures 1-2 As shown, the utility model includes a DC bushing 1 and a protective sleeve assembly 5, wherein the protective sleeve assembly 5 passes through the fire wall body 3, and the protective sleeve assembly 5 includes a wall-penetrating flange sleeve 501 and a shielding tube 504 mounted on the outside of the wall-penetrating flange sleeve 501, and a fireproof layer 502 is provided between the wall-penetrating flange sleeve 501 and the shielding tube 504, the DC bushing 1 includes an outer insulating sleeve 101 and a bushing plug-in portion 102, and the outer insulating sleeve 101 and the bushing plug-in portion 102 are connected through the wall-penetrating flange sleeve 501, and the lower end of the outer insulating sleeve 101 is provided with a voltage-equalizing shielding protective cover 6 that covers all the corresponding ends of the protective sleeve assembly 5, and the voltage-equalizing shielding protective cover 6 is grounded. In this embodiment, the voltage-equalizing shielding protective cover 6 adopts an ellipsoidal structure and is grounded. It is made of non-magnetic aluminum alloy material. In addition, the shielding tube 504 is made of non-magnetic stainless steel material. This can achieve complete electromagnetic shielding and zero-loop grounding effect for each metal component passing through the fire wall body 3. Therefore, the utility model can effectively avoid the problem of overheating of metal components caused by eddy current and circulation loss in the leakage magnetic field, and at the same time can shield the strong electric field inside the valve hall, thereby effectively avoiding the risk of local discharge and local overheating of the casing's own structural components caused by strong electromagnetic field interference and strong current. In addition, the utility model uses the fireproof layer 502 between the wall flange sleeve 501 and the shielding tube 504 and other structures to achieve flame retardant, explosion-proof and accident isolation functions. Figures 1-2 As shown, the ellipsoidal shape of the pressure-equalizing shielding protective cover 6 needs to be designed to match the wall penetration angle of the wall penetration flange sleeve 501 to ensure that the pressure-equalizing shielding protective cover 6 can fully fit with the fire wall body 3 to achieve seamless shielding.

[0026] like Figure 2As shown, in this embodiment, fireproof baffles 505 are provided at both ends of the shielding tube 504, and the fireproof baffles 505 are mounted on the wall flange sleeve 501. The fireproof layer 502 is provided between the two fireproof baffles 505 to achieve position limiting. In this embodiment, the fireproof layer 502 is made of aluminum silicate needle-punched fireproof cotton (high temperature resistant above 1400°C), and the fireproof baffles 505 are magnesium fireproof board (a high temperature resistant hard board that is heat-insulating, flame-retardant and explosion-proof, and is a material well known in the art).

[0027] like Figure 2 As shown, in this embodiment, a polyester material layer 503 is provided between the fireproof layer 502 and the shielding tube 504. When assembling this embodiment, the aluminum silicate needle-punched fireproof cotton forming the fireproof layer 502 is first filled between the two fireproof baffles 505 on the outside of the wall flange sleeve 501, and then a film-like polyester material (polyester film) is used to wrap around the aluminum silicate needle-punched fireproof cotton to ensure that the aluminum silicate needle-punched fireproof cotton is filled tightly and the density meets the requirements. After the film-like polyester material is wrapped, the polyester material layer 503 is formed. The thickness of the polyester material layer 503 also needs to ensure that it can fit closely with the outer shielding tube 504 to achieve compaction of the fireproof layer 502.

[0028] When the present invention is used, the shielding tube 504, fireproof layer 502 and other structures can achieve a radial flame retardant effect, that is, when a fire and explosion failure occurs in the external converter transformer 4, the heat of the fire cannot be transmitted through the shielding tube 504, fireproof layer 502 and other structures. In addition to limiting the position of the fireproof layer 502, the fire baffle 505 can also achieve an axial flame retardant effect, and at the same time can fully ensure the sealing performance of the fireproof layer 502.

[0029] like Figure 2 As shown, in this embodiment, a lower connecting flange 5012 is provided at the lower end of the wall-penetrating flange sleeve 501, a mounting flange 1021 is provided at the upper end of the sleeve plug-in portion 102, and the lower connecting flange 5012 is fixedly connected to the mounting flange 1021 by fastening bolts, and a sealant 506 is filled between the outer side of the connection between the lower connecting flange 5012 and the mounting flange 1021 and the shielding tube 504 to achieve a flame-retardant sealing effect, and the sealant 506 is provided at the lower end of the shielding tube 504 and is pressed and fixed by the shielding tube 504.

[0030] like Figure 2As shown, in this embodiment, the upper end of the through-wall flange sleeve 501 is provided with an upper connecting flange 5011, the lower end of the outer insulating sleeve 101 is provided with an outer insulating sleeve flange 1011, the inner part of the voltage-equalizing shielding protective cover 6 is provided with a protective cover flange 601, and the upper connecting flange 5011, the outer insulating sleeve flange 1011 and the protective cover flange 601 are fixedly connected by fastening bolts, wherein the upper end of the shielding cylinder 504 is provided with a bent baffle 5041, and the bent baffle 5041 is welded and fixedly connected to the upper connecting flange 5011, and a sealant layer 507 is provided between the outer insulating sleeve flange 1011, the upper connecting flange 5011 and the bent baffle 5041 to achieve flame retardant sealing. The bent baffle 5041 can also cooperate with two fireproof baffles 505 to further ensure the axial flame retardant effect.

[0031] In this embodiment, both the sealant 506 and the sealant layer 507 are made of a fireproof insulating sealant (high-temperature resistant, flame-retardant, explosion-proof, isolating, and sealing material, and is a material known in the art). This allows for a seamless flame-retardant and explosion-proof structure to be formed between the protective sleeve assembly 5 and the DC bushing 1. Furthermore, fastening bolts are used to achieve a single-point short-circuit between the lower connecting flange 5012 of the through-wall flange sleeve 501 and the mounting flange 1021, as well as between the upper connecting flange 5011 of the through-wall flange sleeve 501 and the outer insulating sleeve flange 1011 and the protective cover flange 601. This further prevents heat generation caused by circulating current losses between components due to magnetic leakage induction, which can lead to overheating, discharge, and even fire.

[0032] like Figure 2 As shown, the conductive tube 103 and the inner insulating capacitor core 104 inside the DC bushing 1 both pass through the wall flange sleeve 501, wherein the inner insulating capacitor core 104 is attached to the conductive tube 103, and in this embodiment, the inner insulating capacitor core 104 is made of epoxy resin impregnated paper, and the space between the inner insulating capacitor core 104 and the outer insulating sleeve 101 and the wall flange sleeve 501 is filled with insulating gas 105 (SF6 gas in this embodiment), thereby realizing an oil-free design of the DC bushing 1 itself, thereby effectively improving the insulation strength and safe operation margin of the DC bushing 1 itself, avoiding the occurrence of self-explosion problems, and also preventing the fire and the expansion of problems when serious faults such as explosion and fire occur in the converter transformer 4, thereby avoiding damage to high-cost equipment such as the converter valve in the valve hall.

[0033] The working principle of this utility model is:

[0034] like Figure 1As shown, when the present invention is used, the main part of the DC bushing 1 is arranged in the inner area 2 of the valve hall, and the converter transformer 4 is arranged in the outer area of ​​the valve hall. At the same time, the bushing plug-in portion 102 of the DC bushing 1 is connected to the converter transformer 4 in the outer area of ​​the valve hall, and the protective cover assembly 5 passes through the fire wall 3 between the inner area 2 of the valve hall and the outer area of ​​the valve hall. Figure 2 As shown, the lower end of the outer insulating sleeve 101 of the DC bushing 1 is connected to the bushing plug-in portion 102 through the wall flange sleeve 501 in the protective sleeve assembly 5.

[0035] like Figure 2 As shown, first of all, the utility model is provided with a voltage-equalizing shielding protective cover 6 at the lower end of the outer insulating sleeve 101, which covers all the corresponding ends of the protective sleeve assembly 5, and the voltage-equalizing shielding protective cover 6 is grounded. At the same time, the protective sleeve assembly 5 includes a shielding tube 504, and the voltage-equalizing shielding protective cover 6 and the shielding tube 504 are both made of non-magnetic metal material, which can achieve complete electromagnetic shielding and zero-loop grounding effect for each metal component passing through the fire wall body 3. Therefore, the utility model can effectively avoid the problem of overheating of metal components caused by eddy current and circulating current loss in the leakage magnetic field, and can also shield the strong electric field inside the valve hall, thereby effectively avoiding the risk of local discharge and local overheating of the sleeve's own structural components caused by strong electromagnetic field interference, strong current, etc. The elliptical spherical shape of the voltage-equalizing shielding protective cover 6 is designed to match the wall penetration angle of the wall-penetrating flange sleeve 501, which can also ensure that the voltage-equalizing shielding protective cover 6 is fully fitted with the fire wall body 3 to achieve seamless shielding.

[0036] Secondly, Figure 2 As shown, the protective sleeve assembly 5 of the present invention includes a fireproof layer 502 arranged between the wall-penetrating flange sleeve 501 and the shielding tube 504, and the fireproof layer 502 is limited by the fireproof baffle 505 at both axial ends, and is also radially wrapped and compacted by the polyester material layer 503. The above structure can not only achieve the radial flame retardant and axial flame retardant effects of the protective sleeve assembly 5, but also fully ensure the sealing performance of the fireproof layer 502.

[0037] Again Figure 2As shown, the lower end of the through-wall flange sleeve 501 is provided with a lower connecting flange 5012 which is fixedly connected to the mounting flange 1021 at the upper end of the sleeve plug-in portion 102, and the gap between the lower connecting flange 5012 and the mounting flange 1021 is covered with a sealant 506 to ensure flame retardant sealing, the upper end of the through-wall flange sleeve 501 is provided with an upper connecting flange 5011 which is fixedly connected to the outer insulating sleeve flange 1011 at the lower end of the outer insulating sleeve 101 and the protective cover flange 601 inside the equalizing shielding protective cover 6, wherein the upper end of the shielding tube 504 is provided with a folding Bent baffle 5041, and a sealant layer 507 is provided between the outer insulating sleeve flange 1011, the upper connecting flange 5011 and the bent baffle 5041 to ensure the flame retardant sealing effect. The utility model uses the sealant 506 and the sealant layer 507 to form a seamless flame retardant and explosion-proof structure between the protective sleeve assembly 5 and the DC bushing 1. At the same time, each of the above-mentioned flanges adopts fastening bolts to achieve a single-point short-circuit effect, which can further avoid the circulation loss formed between the components due to leakage magnetic induction, causing heat and bringing about overheating discharge and even fire failure.

[0038] Finally, Figure 2 As shown, the inner insulating capacitor core 104 inside the DC bushing 1 is made of epoxy resin impregnated paper, and the inner insulating capacitor core 104 and the outer insulating sleeve 101 and the wall flange sleeve 501 are filled with insulating gas 105, thereby realizing an oil-free design of the bushing itself. This not only effectively improves the insulation strength and safe operation margin of the DC bushing 1 itself, but also can prevent the fire and the expansion of serious faults such as explosion and fire in the converter transformer 4, and avoid damage to high-cost equipment such as the converter valve in the valve hall.

Claims

1. A converter transformer DC bushing with wall penetration protection function, characterized by: The invention comprises a DC bushing (1) and a protective sleeve assembly (5), wherein the protective sleeve assembly (5) passes through a fire wall body (3), and the protective sleeve assembly (5) comprises a through-wall flange sleeve (501) and a shielding cylinder (504) sleeved on the outside of the through-wall flange sleeve (501), a fireproof layer (502) is provided between the through-wall flange sleeve (501) and the shielding cylinder (504), and the DC bushing (1) comprises an outer insulating sleeve (101) and a bushing plug-in portion (102), and the outer insulating sleeve (101) and the bushing plug-in portion (102) are connected by the through-wall flange sleeve (501). The outer insulating sleeve (101) is connected to the wall flange sleeve (501); the lower end of the outer insulating sleeve (101) is provided with a voltage-equalizing shielding protective cover (6) that completely covers the corresponding ends of the protective sleeve assembly (5), and the voltage-equalizing shielding protective cover (6) is grounded; the DC bushing (1) is provided with a conductive tube (103) and an inner insulating capacitor core (104), and the inner insulating capacitor core (104) is sleeved on the conductive tube (103); and insulating gas (105) is filled between the inner insulating capacitor core (104), the outer insulating sleeve (101) and the wall flange sleeve (501).

2. The converter transformer DC bushing with wall penetration protection function according to claim 1, characterized in that: Fireproof baffles (505) are provided inside both ends of the shielding tube (504), and the fireproof layer (502) is provided between the two fireproof baffles (505).

3. The converter transformer DC bushing with wall penetration protection function according to claim 1, characterized in that: A polyester material layer (503) is provided between the fireproof layer (502) and the shielding tube (504).

4. The converter transformer DC bushing with wall penetration protection function according to claim 1, characterized in that: The lower end of the wall-penetrating flange sleeve (501) is provided with a lower connecting flange (5012), the upper end of the sleeve plug-in portion (102) is provided with a mounting flange (1021), and the lower connecting flange (5012) and the mounting flange (1021) are fixedly connected by fastening bolts, and a sealant (506) is provided between the outer side of the connection between the lower connecting flange (5012) and the mounting flange (1021) and the shielding tube (504).

5. The converter transformer DC bushing with wall penetration protection function according to claim 1, characterized in that: An upper connecting flange (5011) is provided at the upper end of the through-wall flange sleeve (501), an outer insulating sleeve flange (1011) is provided at the lower end of the outer insulating sleeve (101), a protective cover flange (601) is provided inside the voltage-equalizing shielding protective cover (6), and the upper connecting flange (5011), the outer insulating sleeve flange (1011) and the protective cover flange (601) are fixedly connected by fastening bolts.

6. The converter transformer DC bushing with wall penetration protection function according to claim 5, characterized in that: A bending baffle (5041) is provided at the upper end of the shielding tube (504), and the bending baffle (5041) is fixedly connected to the upper connecting flange (5011), and a sealing rubber layer (507) is provided between the outer insulating sleeve flange (1011), the upper connecting flange (5011) and the bending baffle (5041).

7. The converter transformer DC bushing with wall penetration protection function according to claim 1, characterized in that: The pressure-equalizing shielding protective cover (6) is an ellipsoidal spherical structure and fits closely with the fire wall body (3).

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