Winding structure of current-limiting reactor matched with on-load tap changer

Abstract

The application relates to the technical field of power equipment, and discloses a winding structure of a current-limiting reactor matched with an on-load tap changer, which comprises a winding body wound on an insulating framework, and the winding body comprises a first layer winding, a second layer winding, a third layer winding and a fourth layer winding wound in a spiral structure and arranged radially from inside to outside in sequence; wherein the first layer winding is right-handed, the first end of the first layer winding is defined as a terminal P2, and the second end of the first layer winding is defined as a common connection point P'; the second layer winding is right-handed, the first end of the second layer winding is defined as a terminal P4, and the second end of the second layer winding is connected with the second end of the third layer winding; the third layer winding is left-handed, the first end of the third layer winding is defined as a terminal P3; and the fourth layer winding is left-handed, the first end of the fourth layer winding is defined as a terminal P1, and the second end of the fourth layer winding is defined as the common connection point P'. The scheme omits the complicated axial cross transposition, simplifies the manufacturing process, and significantly reduces the axial height of the winding.

Description

Technical Field

[0001] This utility model relates to the field of power equipment technology, and more specifically, to a winding structure of a current-limiting reactor for use with an on-load tap changer. Background Technology

[0002] On-load tap changers are key components for transformers to achieve voltage regulation under load. During their operation, especially in the bridging (cross-connection) state when switching taps, a circulating current is generated between the two taps. To limit this circulating current, a current-limiting reactor is required. This reactor must meet the requirements of two operating modes: when the switch is in the cross-connection position, the reactor should exhibit sufficient inductance to limit the circulating current; when the switch is in the non-cross-connection position, the magnetic flux generated by the two parallel branches of the reactor should be able to cancel each other out, thereby reducing leakage flux and its impact on the transformer body, and reducing the reactor's own losses.

[0003] In existing technologies, the windings of such reactors often employ a complex axial X-shaped cross arrangement structure, such as the scheme disclosed in CN116246860A. While this structure can achieve the function of flux cancellation, it suffers from problems such as complex manufacturing processes, large axial height of the windings, and low space utilization, resulting in a large overall reactor size, which is not conducive to compact arrangement within the transformer tank. In addition, the lead-out directions of the winding terminals may be dispersed, increasing the complexity of the connection with the switch.

[0004] Therefore, there is an urgent need in this field for a new type of current-limiting reactor winding structure that can simplify the manufacturing process, reduce the axial dimension, and facilitate wiring while ensuring electrical performance. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a winding structure for a current-limiting reactor used with an on-load tap changer. This structure achieves miniaturization, low loss and ease of manufacturing through a unique radial layered arrangement and internal connection method.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A winding structure for a current-limiting reactor used with an on-load tap changer includes a winding body wound on an insulating frame. The winding body comprises a first layer winding, a second layer winding, a third layer winding, and a fourth layer winding arranged radially from the inside out in a helical structure. The first layer winding is right-hand winding, with its first end defined as terminal P2 and its second end defined as common connection point P'. The second layer winding is right-hand winding, with its first end defined as terminal P4 and its second end connected to the second end of the third layer winding. The third layer winding is left-hand winding, with its first end defined as terminal P3. The fourth layer winding is left-hand winding, with its first end defined as terminal P1 and its second end defined as common connection point P'.

[0007] Furthermore, the insulating frame includes an inner paper tube, a middle paper tube, and an outer paper tube; a first set of support bars is provided on the outer side of the inner paper tube, and the first layer winding is wound on the first set of support bars; a second set of support bars is provided on the outer side of the first layer winding, and the second layer winding is wound on the second set of support bars; the middle paper tube and a third set of support bars are provided on the outer side of the second layer winding, and the third layer winding is wound on the third set of support bars; a fourth set of support bars is provided on the outer side of the third layer winding, and the fourth layer winding is wound on the fourth set of support bars; the outer paper tube and a fifth set of support bars are provided on the outer side of the fourth layer winding.

[0008] The multi-layer paper tube and support bars provide independent and stable support for each layer of winding, ensuring the concentricity and mechanical strength of the windings. The grooves between the support bars form axial heat dissipation channels, improving the cooling effect.

[0009] Furthermore, insulating components are provided between each layer of winding in the first, second, third, and fourth layers of winding, as well as at the ends of the windings; the insulating components include pads provided at the interlayer conductor turns, end rings provided at the ends of the windings, a lower support plate and a lower pad provided at the lower part of the windings, and a pressure plate and an upper pad provided at the upper part of the windings.

[0010] The insulation strength of the winding ends and the whole is ensured by components such as end rings, pads, support plates and pressure plates of the insulating parts, and the clamping structure prevents the winding from loosening and reduces vibration and noise.

[0011] Furthermore, the first group of support bars, the second group of support bars, the third group of support bars, the fourth group of support bars, and the fifth group of support bars are evenly distributed along the circumferential direction.

[0012] The evenly distributed circumference of the support bars ensures uniform stress on the windings and optimized heat dissipation.

[0013] Furthermore, the terminals P1, P2, P3 and P4 are all arranged at the same axial end of the winding.

[0014] By arranging all terminals at the same axial end, the connection with the switch is simplified, and installation efficiency is improved.

[0015] Furthermore, the common connection point P' is formed by connecting the second end of the first layer winding to the second end of the fourth layer winding through a wire.

[0016] Furthermore, the second end of the second layer winding is connected to the second end of the third layer winding via a wire.

[0017] Furthermore, the winding body is wound with self-adhesive transposed wire.

[0018] By using self-adhesive transposed wires to wind the windings, the mechanical strength and short-circuit withstand capability of the windings are enhanced, and eddy current losses are reduced.

[0019] The beneficial effects of this invention are as follows: By connecting the first layer and the second terminal to the fourth layer and the second terminal to form a common connection point P', and by connecting the second layer and the second terminal to the third layer and the second terminal, a specific electrical path is achieved. When the on-load tap changer is in the non-bridging position, the current paths are P1-P'-P2 and P4-P3. Specifically, the P1-P'-P2 path includes the fourth layer and the first layer connected in parallel; due to the leftward winding of the fourth layer and the rightward winding of the first layer, the magnetic flux cancels out. The P4-P3 path includes the second layer and the third layer connected in parallel; due to the rightward winding of the second layer and the leftward winding of the third layer, the magnetic flux cancels out. This structure ensures that the core magnetic flux is almost completely canceled out in the non-bridging position, reducing leakage flux and losses. When the switch is in the bridging position, the current path is P1-P'-P2-P3-P4, with the four winding layers forming a series connection, providing high inductive reactance to limit circulating current. This solution eliminates the complex axial cross-transposition, simplifies the manufacturing process, and significantly reduces the axial height of the windings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a cross-sectional view of the winding structure of this utility model; Figure 2 This is a simplified diagram illustrating the electrical connection principle of the winding structure of this utility model.

[0022] Reference numerals in the attached diagram: 1-Inner paper tube; 2-First set of support bars; 3-Second set of support bars; 4-Third set of support bars; 5-Middle paper tube; 6-Fourth set of support bars; 7-Fifth set of support bars; 8-Outer paper tube; 9-Upper pad; 10-End ring; 11-Lower pad; 12-Lower support plate; 13-Pressure plate. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] It should be noted that the directional terms such as "upper," "middle," "lower," "inner," and "outer" used below are defined based on the accompanying drawings in the instruction manual.

[0026] In this article, the first end refers to the starting end or head of the winding, and the second end refers to the ending end or tail of the winding.

[0027] like Figure 1 As shown, the winding structure provided in this embodiment is wound sequentially on the insulating frame from the inside out. First, a first set of support bars 2 is bonded to the inner paper tube 1. Then, a first layer of winding is wound on the first set of support bars 2. This layer of winding is right-handed, with its first end defined as terminal P2, and its second end reserved as a common connection point P' during the winding process. Next, a second set of support bars 3 is installed outside the first layer of winding, and a second layer of winding is wound on it. This layer of winding is right-handed, with its first end defined as terminal P4, and its second end reserved during the winding process. Afterward, an intermediate paper tube 5 and a third set of support bars 4 are installed outside the second layer of winding, and a third layer of winding is wound on the third set of support bars 4. This layer of winding is left-handed, with its first end defined as terminal P3, and its second end connected to the second end of the second layer of winding via a wire during the winding process. Then, a fourth set of support bars 6 is installed on the outside of the third layer winding, and a fourth layer winding is wound on it. This layer winding is left-handed, and its first end is defined as terminal P1. Its second end is connected to the second end of the first layer winding through a wire during the winding process, forming a common connection point P'. Finally, an outer paper tube 8 and a fifth set of support bars 7 are installed on the outside of the fourth layer winding. End rings 10 are placed at the ends of each layer winding. A lower support plate 12 and a lower pad 11 are set below the entire winding, and a pressure plate 13 and an upper pad 9 are set above. Pressure is applied by a clamping device to make the entire winding form a stable whole.

[0028] Its electrical working principle is as follows Figure 2 As shown: Non-bridging position: An external switch splits the current into two paths. One path is P1-P'-P2, where the fourth layer and the first layer are connected in parallel. Because the fourth layer winds to the left and the first layer winds to the right, the resulting magnetomotive force is in opposite directions, and the magnetic flux cancels out. The other path is P4-P3, where the second layer and the third layer are connected in parallel. Because the second layer winds to the right and the third layer winds to the left, the resulting magnetomotive force is in opposite directions, and the magnetic flux cancels out. The reactor as a whole exhibits low inductive reactance, reducing losses and leakage flux.

[0029] Jumper position: An external switch allows current to flow through the path P1-P'-P2-P3-P4. The four windings are connected in series, and their inductive reactance is superimposed, which together limits the circulating current.

[0030] In some embodiments, the windings are made of self-adhesive transposed wire. After winding, a vacuum drying process is performed, and the self-adhesive varnish on the wire is cured at high temperature. At the same time, a specified clamping force is applied by a pressure plate to solidify the windings and insulation into a solid whole. Each support bar group is formed by multiple epoxy resin support bars evenly distributed along the circumference.

[0031] The radial arrangement of the four winding layers results in a lower axial height of the winding body compared to a winding structure with the same function but arranged in an axially crossed pattern.

[0032] Through the above-described specific structural design, this utility model successfully achieves the goals of simplifying the process, reducing the size, facilitating installation, and improving performance.

[0033] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0034] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0035] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A winding structure for a current-limiting reactor used with an on-load tap changer, characterized in that, The device includes a winding body wound on an insulating frame. The winding body comprises a first layer of winding, a second layer of winding, a third layer of winding, and a fourth layer of winding wound radially from the inside out in a helical structure. The first layer of winding is right-hand winding, with its first end defined as terminal P2 and its second end defined as common connection point P'. The second layer of winding is right-hand winding, with its first end defined as terminal P4 and its second end connected to the second end of the third layer of winding. The third layer of winding is left-hand winding, with its first end defined as terminal P3. The fourth layer of winding is left-hand winding, with its first end defined as terminal P1 and its second end defined as common connection point P'.

2. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 1, characterized in that, The insulating frame includes an inner paper tube, a middle paper tube, and an outer paper tube; a first set of support bars is provided on the outer side of the inner paper tube, and the first layer winding is wound on the first set of support bars; a second set of support bars is provided on the outer side of the first layer winding, and the second layer winding is wound on the second set of support bars; the middle paper tube and a third set of support bars are provided on the outer side of the second layer winding, and the third layer winding is wound on the third set of support bars; a fourth set of support bars is provided on the outer side of the third layer winding, and the fourth layer winding is wound on the fourth set of support bars; the outer paper tube and a fifth set of support bars are provided on the outer side of the fourth layer winding.

3. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 2, characterized in that, Insulating components are provided between each layer of windings in the first layer, the second layer, the third layer, and the fourth layer, as well as at the ends of the windings. The insulating components include a pad provided at the interlayer conductor turn, an end ring provided at the end of the winding, a lower support plate and a lower pad provided at the lower part of the winding, and a pressure plate and an upper pad provided at the upper part of the winding.

4. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 2, characterized in that, The first group of support bars, the second group of support bars, the third group of support bars, the fourth group of support bars and the fifth group of support bars are evenly distributed along the circumference.

5. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 1, characterized in that, Terminals P1, P2, P3, and P4 are all located at the same axial end of the winding.

6. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 1, characterized in that, The common connection point P' is formed by connecting the second end of the first layer winding to the second end of the fourth layer winding through a wire.

7. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 1, characterized in that, The second end of the second layer winding is connected to the second end of the third layer winding by a wire.

8. The winding structure of a current-limiting reactor for use with an on-load tap changer according to claim 1, characterized in that, The winding body is wound with self-adhesive transposed wire.

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