Internal current limiting reactor
By improving the structural design of the current-limiting reactor, adopting a hollow spiral coil and simplifying the connection method, the problems of high cost, large space occupation, and weak short-circuit resistance of existing current-limiting reactors have been solved, achieving the effects of lower cost, stronger short-circuit resistance and smaller installation space.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TBEA SHENYANG TRANSFORMER GRP CO LTD
- Filing Date
- 2021-07-07
- Publication Date
- 2026-06-26
AI Technical Summary
Current current-limiting reactors are expensive, have complex structures, occupy a large space, have weak short-circuit withstand capability, and have high noise levels, making it difficult to meet the installation requirements of large-capacity transformers.
It adopts an upper yoke, coil, and lower yoke structure. The coil is a hollow spiral type, and the conductor is a single paper-insulated wire. It adopts the Pango transposition method and sets oil baffles between the windings. The connection method is simplified to upper and lower exits, which are fixed by vertical screws and butterfly springs. The connection between the coil and the transformer is simple, and it is installed in a standard oil tank.
It reduces costs and losses, improves short-circuit withstand capability, reduces installation space and noise, simplifies the connection process, and is suitable for the installation of large-capacity transformers.
Smart Images
Figure CN115602421B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of transformer technology, specifically to a built-in current-limiting reactor. Background Technology
[0002] With the increasing installed capacity of power transformers, the resulting increase in short-circuit current can cause significant damage to various electrical equipment on the power grid. To limit the short-circuit current, high-impedance transformers are needed in the power grid. A common method in existing technology is to connect a current-limiting reactor in series with the transformer windings to increase the transformer impedance. The current-limiting reactor is usually connected in series on the low-voltage side of the transformer and placed in the same tank as the transformer body. Because the low-voltage side of the transformer has a large rated current and short-circuit current, the current-limiting reactor generally needs to adopt a special structural form to meet the requirements of temperature rise, short-circuit force, and vibration. Strict requirements regarding dynamic noise and other aspects exist. For example, Chinese invention patent CN207367766U discloses a built-in transformer current limiting device, which includes multiple branches, each consisting of a capacitor, a current-limiting reactor, and a fast switch connected in parallel. This allows for automatic switching of the current-limiting reactor and automatic impedance adjustment, thereby reducing short-circuit current surges. However, the device's fixing structure includes components such as shielded aluminum cylinders, basin-type insulators, and flanges, which are difficult to meet the fixing requirements of large-capacity, large-volume transformers. Furthermore, the fast switch and other structures increase costs. Additionally, the traditional solution for current-limiting reactors uses a hollow double-continuous central-outlet coil structure with self-adhesive transposed conductors. The upper and lower yokes are directly welded, and leads are added after assembly onto the transformer. This solution is costly, has a complex connection structure with the transformer, a long production cycle, significant structural losses, weak short-circuit resistance, and high noise levels. Moreover, the reactor occupies a large space, often requiring a partial expansion of the tank to accommodate it, thus increasing the tank's size. Summary of the Invention
[0003] The purpose of this invention is to provide a built-in current-limiting reactor that has lower cost, lower loss, stronger short-circuit resistance, and shorter production cycle while also reducing installation space requirements.
[0004] The objective of this invention is achieved through the following technical solution:
[0005] An internal current-limiting reactor includes an upper yoke, a coil, and a lower yoke arranged sequentially from top to bottom. The upper yoke has an upper yoke frame, an upper connecting seat on the upper side of the upper yoke frame, and an upper silicon steel sheet inside the upper yoke frame. The upper silicon steel sheet is insulated from the upper yoke frame and connected to the upper connecting seat. The upper connecting seat is connected to the corresponding upper clamp of the transformer. The lower yoke has a lower yoke frame, a pad on the lower side of the lower yoke frame, and a lower silicon steel sheet inside the lower yoke frame. The lower silicon steel sheet is insulated from the lower yoke frame and connected to the corresponding pad. The pad is connected to the corresponding lower clamp of the transformer. A vertical screw is provided between the upper yoke and the lower yoke. The upper end of the vertical screw is fixed to the corresponding upper connecting seat, and the lower end is fixed to the corresponding pad. An upper lead bus and a lower lead bus are provided on the outside of the coil. The upper lead bus and the lower lead bus are respectively connected to the corresponding low-voltage lead bus of the transformer.
[0006] The coil is a hollow spiral coil and the conductor is a single paper-insulated wire.
[0007] The coil has a structure of multiple wires wound in parallel, and the wires are transposed using the Pango transposition method, with the number of transpositions being the same as the number of wires wound in parallel.
[0008] An oil baffle is provided inside the coil.
[0009] The upper yoke includes an upper yoke web and an upper yoke horizontal screw. The two upper yoke webs are respectively located on both sides of the upper silicon steel sheet. The two ends of the upper yoke horizontal screw are respectively connected to the upper yoke webs on the corresponding sides. The upper yoke webs are insulated from the upper silicon steel sheet, and the upper yoke horizontal screw is insulated from the upper yoke webs. The upper connecting seat is located on the upper side of the upper yoke webs.
[0010] The upper connecting seat is insulated from the corresponding upper clamp of the transformer, and any set of upper connecting seats and upper clamps of the transformer are connected to the grounding wire.
[0011] The lower yoke frame includes a lower yoke web and a lower yoke horizontal screw. The two lower yoke webs are respectively located on both sides of the lower silicon steel sheet. The two ends of the lower yoke horizontal screw are respectively connected to the lower yoke webs on the corresponding sides. The lower yoke webs are insulated from the lower silicon steel sheet, and the lower yoke horizontal screw is insulated from the lower yoke webs. The pad is located on the lower side of the lower yoke web.
[0012] The pads are insulated from the lower clamp of the transformer, and any set of pads and the lower clamp of the transformer are connected to the grounding wire.
[0013] The coil has an upper lead and a lower lead, and the upper lead is connected to the upper lead busbar, and the lower lead is connected to the lower lead busbar.
[0014] The vertical screw is equipped with butterfly springs at both ends, and a pressure cylinder is provided between the upper clamp of the transformer and the corresponding upper connecting seat.
[0015] The advantages and positive effects of this invention are as follows:
[0016] 1. In this invention, the silicon steel sheets in the upper and lower yokes are clamped and fixed by the web plates on both sides, which eliminates the need to drill holes or weld on the silicon steel sheets, thus avoiding damage to the silicon steel sheet structure and reducing structural losses. The upper and lower yokes are tightened and fixed by a vertical screw, which strengthens the coil's short-circuit resistance and effectively reduces noise.
[0017] 2. The coil of this invention uses a single paper-insulated wire, which reduces the cost of the conductor. It also uses a Pango transposition spiral coil, which reduces circulating current loss and allows for faster winding. In addition, an oil baffle is added, resulting in lower winding temperature rise.
[0018] 3. The coil of the present invention has a double-outlet structure with an upper and a lower outlet. Compared with the existing three-outlet structure of the upper, middle and lower, it is simpler to connect with the transformer. Furthermore, the coil outlet is led to one side through the upper lead bus and the lower lead bus, which facilitates connection with the low-voltage side of the transformer. At the same time, the distance between the reactor and the transformer does not need to consider the distance of manually configured leads, only the insulation distance, thereby effectively reducing the distance between the reactor and the transformer.
[0019] 4. The present invention can set a pressure cylinder between the upper clamp and the upper connecting seat of the transformer to further press the transformer body, thereby further improving the short circuit resistance of the reactor and effectively reducing the noise generated by the reactor.
[0020] 5. This invention is very small in size and can be placed in the oil tank together with the transformer. The oil tank is a standard oil tank, and its width direction can be consistent with that of the transformer. There is no need to expand the installation space for the reactor. Attached Figure Description
[0021] Figure 1 This is the front view of the present invention.
[0022] Figure 2 for Figure 1 Top view of the present invention.
[0023] Figure 3 This is a simplified schematic diagram of a structure according to the present invention.
[0024] Figure 4 This is a simplified schematic diagram of another structure of the present invention.
[0025] Figure 5 for Figure 1 A diagram illustrating the transposition of the center coil.
[0026] Figure 6 for Figure 1 Schematic diagram of the lead wire and oil baffle of the intermediate coil.
[0027] Among them, 1 is the lower yoke, 101 is the lower yoke web, 102 is the lower yoke horizontal screw, 103 is the pad, 2 is the coil, 201 is the single paper-insulated wire, 202 is the upper protrusion, 203 is the lower protrusion, 204 is the oil baffle, 3 is the upper yoke, 301 is the upper yoke web, 302 is the upper yoke horizontal screw, 303 is the upper connecting seat, 4 is the upper lead busbar, 5 is the vertical screw, 6 is the lower lead busbar, 7 is the transformer, 701 is the transformer upper clamp, 702 is the transformer lower clamp, 703 is the transformer low-voltage lead busbar, 8 is the oil tank, and 9 is the grounding wire. Detailed Implementation
[0028] The invention will now be described in further detail with reference to the accompanying drawings.
[0029] like Figures 1-6 As shown, the present invention includes an upper yoke 3, a coil 2, and a lower yoke 1 arranged sequentially from top to bottom. The upper yoke 3 has an upper yoke frame, an upper connecting seat 303 on its upper side, and an upper silicon steel sheet inside. The upper silicon steel sheet is insulated from the upper yoke frame and connected to the upper connecting seat 303 via a first grounding plate. The upper connecting seat 303 is connected to the corresponding upper clamp 701 on the transformer 7. The lower yoke 1 has a lower yoke frame, a pad 103 on its lower side, and a lower silicon steel sheet inside. The lower silicon steel sheet is insulated from the lower yoke frame and connected to the corresponding pad 103 via a second grounding plate. The pad 103 is connected to the corresponding lower clamp 702 on the transformer 7. A vertical screw 5 is provided between the upper yoke 3 and the lower yoke 1. The upper end of the vertical screw 5 is fixed to the corresponding upper connecting seat 303, and the lower end is fixed to the corresponding pad 103, thereby tightening and fixing the upper yoke 3, coil 2, and lower yoke 1. Figure 1 and Figure 2 As shown, the upper outer side of coil 2 is provided with an upper lead busbar 4, and the lower outer side is provided with a lower lead busbar 6. The upper lead busbar 4 and the lower lead busbar 6 are respectively connected to the corresponding low-voltage lead busbar 703 on transformer 7. In this embodiment, the upper lead busbar 4, the lower lead busbar 6, and the low-voltage lead busbar 703 are all copper busbars, and the first grounding plate and the second grounding plate are both copper plates.
[0030] like Figures 1-2As shown, the upper yoke includes an upper yoke web 301 and an upper yoke horizontal screw 302. The two upper yoke webs 301 are respectively disposed on both sides of the upper silicon steel sheet. The two ends of the upper yoke horizontal screw 302 are connected to the corresponding upper yoke webs 301, thereby tightening and clamping the upper silicon steel sheet in the middle. The upper yoke webs 301 are insulated from the upper silicon steel sheet, and the upper yoke horizontal screw 302 is also insulated from the upper yoke webs 301 to prevent circulating current. This insulation can be achieved by using insulating pads or other structural forms, or by using insulating materials for the upper yoke webs 301, which is a well-known technology in the art. An upper connecting seat 303 is disposed on the upper side of the upper yoke webs 301, and the upper silicon steel sheet is connected to the upper connecting seat 303 through a first grounding plate, thereby forming an equipotential connection. This invention does not require drilling or welding on the silicon steel sheet, and does not damage the silicon steel sheet structure, thus effectively reducing silicon steel sheet loss.
[0031] like Figure 1 As shown, the lower yoke includes a lower yoke web 101 and a lower yoke horizontal screw 102. The two lower yoke webs 101 are respectively disposed on both sides of the lower silicon steel sheet. The two ends of the lower yoke horizontal screw 102 are respectively connected to the lower yoke webs 101 on the corresponding sides, thereby tightening and clamping the lower silicon steel sheet in the middle by the lower yoke webs 101 on both sides. Similarly, the lower yoke webs 101 are insulated from the lower silicon steel sheet, and the lower yoke horizontal screw 102 is insulated from the lower yoke webs 101 to prevent the formation of circulation. The pad 103 is disposed on the lower side of the lower yoke webs 101.
[0032] The vertical screw 5 is equipped with butterfly springs at both ends to ensure that the upper yoke 3, coil 2, and lower yoke 1 are pressed together to form a whole and to improve the short-circuit resistance. The butterfly springs are commercially available products.
[0033] like Figures 3-4 As shown, the coil 2 can be a single-phase double-column coil. Figure 3 ) structure, or three-phase three-column ( Figure 4 The structure of the coil 2 is a hollow spiral coil. Compared with the existing double continuous coil, the hollow spiral coil winding is faster to wind, the ampere-turns are more evenly distributed, the short-circuit resistance is stronger, and the current density can be appropriately improved, saving the amount of copper wire used.
[0034] like Figure 5 As shown, the coil 2 conductor uses a single paper-insulated wire 201, which allows the thickness of the paper insulation on the outside of the wire to be selected according to the voltage level, and the cost of the conductor is lower than that of the self-adhesive transposition conductor in the prior art.
[0035] The coil 2 adopts a multi-wire parallel winding structure, and the number of parallel windings can be selected according to the short-circuit current value, usually more than 40 wires are wound in parallel. In addition, in order to reduce circulating current loss, such as Figure 5As shown, the parallel winding adopts the Pango transposition method, and the number of transpositions is the same as the number of parallel windings. This transposition method can effectively reduce the circulating current loss and facilitate winding. The Pango transposition method is a well-known technology in the field.
[0036] like Figure 6 As shown, the coil 2 adopts a structure with an oil baffle 204. Several oil baffles 5 can be installed inside the coil according to actual conditions to reasonably control the oil flow and effectively reduce the coil temperature rise. The oil baffle 5 is a technology known in the art.
[0037] like Figure 6 As shown, the coil 2 adopts an end-out structure, which has an upper outlet 202 and a lower outlet 203. Compared with the prior art, which has three coil outlets (upper, middle and lower) in the middle, the connection between the present invention and the transformer is simpler.
[0038] like Figure 1 As shown, the upper lead 202 of the coil 2 is connected to the upper lead bar 4, and the lower lead 203 is connected to the lower lead bar 6. Figure 2 As shown, the lead-out end of coil 2 is led to the reactor side via upper lead bus 4 and lower lead bus 6, with pre-reserved interfaces for easy connection to the transformer low-voltage lead bus 703. Since the reactor is typically placed on the long axis side of transformer 10, this invention, with pre-installed upper lead bus 4 and lower lead bus 6, eliminates the need to consider the distance for manual lead configuration between the reactor and transformer 7; only the insulation distance needs to be considered, effectively reducing the distance between the reactor and transformer 7 and decreasing the overall size. The upper lead bus 4 and lower lead bus 6 can be connected to the corresponding transformer low-voltage lead bus 703 via connecting tabs or cables, making installation simple and convenient.
[0039] like Figures 1-2 As shown, the upper connecting seat 303 on the upper side of the upper yoke is connected to the corresponding upper clamp 701 on the transformer 7, and it is necessary to ensure that there is insulation between the upper yoke 3 and the upper clamp 701. This insulation can be achieved by setting an insulating pad or other structure, which is a well-known technology in the field. Additionally, as... Figure 1 As shown, one set of upper connecting seats 303 and transformer upper clamp 701 are connected to grounding wire 9 to form equipotential between them. The pads 103 on the lower side of the lower yoke are connected to the corresponding transformer lower clamp 702 on the transformer 7. Similarly, it is necessary to ensure that the pads 103 of the lower yoke 1 are insulated from the transformer lower clamp 702. In addition, as shown in the figure, Figure 1 As shown, one set of pads 103 and the transformer lower clamp 702 are connected to the grounding wire 9 to form equipotential.
[0040] like Figure 1As shown, a pressure cylinder can be installed between the upper clamp 701 of the transformer and the corresponding upper connecting seat 303 to further compress the reactor body, thereby further reducing the noise of the reactor coil 2 and improving the short-circuit withstand capability. The pressure cylinder is a technology known in the art and is a commercially available product.
[0041] like Figure 2 As shown, after the assembly of the present invention is completed, it falls into the oil tank 8 together with the transformer 7. Since the present invention adopts an optimized structure, the reactor size is small, and the oil tank 8 can be a standard rectangular oil tank, which can be consistent with the transformer 7 in the width direction. There is no need to expand the installation space for the reactor locally.
[0042] The working principle of this invention is as follows:
[0043] like Figures 3-6 As shown, the coil 2 of this invention can be a single-phase double-column coil (…). Figure 3 ) structure, or three-phase three-column ( Figure 4 The structure features a hollow spiral coil in each column, with single paper-insulated wire 3 and multiple wires wound in parallel. The parallel windings are transposed using the Pango method. The coil 2 has only two exits, an upper exit 202 and a lower exit 203. The entire coil 2 structure is faster to wind, has a more uniform ampere-turn distribution, lower cost, stronger short-circuit resistance, can effectively reduce circulating current loss, and is simpler to connect with the transformer 7.
[0044] Other examples Figures 1-2 As shown, the upper yoke 3 and the lower yoke 1 of the present invention are connected by a vertical screw 5, which can ensure that the coil 2 is pressed tightly. The upper yoke web 301 on both sides of the upper yoke 3 and the lower yoke web 101 on both sides of the lower yoke 1 are connected by a horizontal screw, so that the silicon steel sheet is clamped and fixed by the corresponding web, thus eliminating the need to drill holes or weld on the silicon steel sheet, preventing damage to the silicon steel sheet structure and reducing structural loss.
[0045] The specific assembly process of this invention is as follows:
[0046] 1. Place the assembled coil 2 on the lower yoke 1. After adjusting the height of each coil 2 to be consistent, place the upper yoke 3 on each coil 2. Then, tighten the upper yoke 3, coil 2 and lower yoke 1 by multiple vertical screws 5. The upper end of the vertical screw 5 is provided with a butterfly spring to ensure that the upper yoke 3, coil 2 and lower yoke 1 are pressed together to form a whole. In addition, bolts are provided on the vertical screw 5 for fixing.
[0047] 2. The present invention is placed on the long axis side of the transformer 7 and between the upper clamp 701 and the lower clamp 702 of the transformer. The upper connecting seat 303 on the upper side of the upper yoke 3 is fixed to the corresponding upper clamp 701 of the transformer by bolts. The pad 103 on the lower side of the lower yoke 1 is fixed to the corresponding lower clamp 702 of the transformer by bolts. Any set of upper connecting seats 303 and upper clamp 701 of the transformer are connected to the grounding wire 9 to form equipotential. Any set of pads 103 and lower clamp 702 of the transformer are connected to the grounding wire 9 to form equipotential.
[0048] 3. Connect the upper lead busbar 4 and the lower lead busbar 6 to the corresponding transformer low-voltage lead busbar 703 via a connector or cable.
[0049] Fourth, a pressure cylinder is placed between the upper clamp 701 and the upper connecting seat 303 of the transformer to further compress the upper yoke 3, coil 2 and lower yoke 1. After compression, the vertical screw 5 is tightened again so that the upper yoke 3, coil 2 and lower yoke 1 are further compressed to form a whole, thereby further reducing the vibration noise of coil 2 and providing short circuit resistance.
[0050] 5. Place the present invention and the transformer 7 together in the oil tank 8. Due to the optimized structure of the present invention, the current limiting reactor is very small. The oil tank 8 is a standard rectangular oil tank, and its width direction can be consistent with that of the transformer. There is no need to expand the installation space for the reactor locally.
Claims
1. A built-in current-limiting reactor, characterized in that: The transformer comprises an upper yoke (3), a coil (2), and a lower yoke (1) arranged sequentially from top to bottom. The upper yoke (3) has an upper yoke frame, an upper connecting seat (303) on the upper side of the upper yoke frame, and an upper silicon steel sheet inside the upper yoke frame. The upper silicon steel sheet is insulated from the upper yoke frame and connected to the upper connecting seat (303). The upper connecting seat (303) is connected to the corresponding upper clamp (701) of the transformer. The lower yoke (1) has a lower yoke frame, a pad (103) on the lower side of the lower yoke frame, and a lower silicon steel sheet inside the lower yoke frame. The lower silicon steel sheet is insulated from the lower yoke frame and connected to the upper connecting seat (303). Connected to the corresponding pad (103), the pad (103) is connected to the corresponding transformer lower clamp (702), a vertical screw (5) is provided between the upper yoke (3) and the lower yoke (1), and the upper end of the vertical screw (5) is fixed to the corresponding upper connecting seat (303) and the lower end is fixed to the corresponding pad (103). An upper lead row (4) and a lower lead row (6) are provided on the outside of the coil (2), and the upper lead row (4) and the lower lead row (6) are respectively connected to the corresponding transformer low voltage lead row (703); The coil (2) is a hollow spiral coil and the conductor is a single paper-insulated wire (201). The coil (2) is a structure with multiple wires wound in parallel, and the parallel wires are transposed using the Pango transposition method, with the number of transpositions being the same as the number of parallel wires. The upper yoke includes an upper yoke web (301) and an upper yoke horizontal screw (302). The two upper yoke webs (301) are respectively disposed on both sides of the upper silicon steel sheet. The two ends of the upper yoke horizontal screw (302) are respectively connected to the upper yoke webs (301) on the corresponding sides. The upper yoke webs (301) on both sides are tightened to clamp and fix the upper silicon steel sheet in the middle. The upper yoke webs (301) are insulated from the upper silicon steel sheet. The upper yoke horizontal screw (302) is insulated from the upper yoke webs (301). The upper connecting seat (303) is disposed on the upper side of the upper yoke webs (301). The lower yoke includes a lower yoke web (101) and a lower yoke horizontal screw (102). The two lower yoke webs (101) are respectively located on both sides of the lower silicon steel sheet. The two ends of the lower yoke horizontal screw (102) are respectively connected to the lower yoke webs (101) on the corresponding sides. The lower yoke webs (101) on both sides are tightened to clamp and fix the lower silicon steel sheet in the middle. The lower yoke webs (101) are insulated from the lower silicon steel sheet. The lower yoke horizontal screw (102) is insulated from the lower yoke webs (101). The pad (103) is located on the lower side of the lower yoke webs (101).
2. The built-in current-limiting reactor according to claim 1, characterized in that: The coil (2) is provided with an oil baffle (204).
3. The built-in current-limiting reactor according to claim 1, characterized in that: The upper connecting seat (303) is insulated from the corresponding upper clamp of the transformer (701), and any set of upper connecting seats (303) and upper clamp of the transformer (701) are connected to the grounding wire (9).
4. The built-in current-limiting reactor according to claim 1, characterized in that: The pads (103) are insulated from the transformer lower clamp (702), and any set of pads (103) and the transformer lower clamp (702) are connected to the grounding wire (9).
5. The built-in current-limiting reactor according to claim 1, characterized in that: The coil (2) has an upper outlet (202) and a lower outlet (203), and the upper outlet (202) is connected to the upper lead row (4), and the lower outlet (203) is connected to the lower lead row (6).
6. The built-in current-limiting reactor according to claim 1, characterized in that: The vertical screw (5) is provided with butterfly springs at both ends, and a pressure cylinder is provided between the upper clamp (701) of the transformer and the corresponding upper connecting seat (303).