A continuous high voltage coil of a dry-type transformer with axial air ducts and a method of winding thereof

Abstract

A dry-type transformer continuous high-voltage coil with axial air ducts comprises a multi-pie pie-shaped coil divided into multiple sub-coils and axial air ducts, each of the sub-coils is wound by insulated conductive wire in a continuous structure, the multiple sub-coils are further divided into n inner sub-coils and m outer sub-coils by the axial air ducts, and an insulating piece is arranged between upper and lower adjacent sub-coils in the inner and outer sub-coils; the upper outgoing wire head of the outer sub-coil at the uppermost end is the head of the high-voltage coil, the lower outgoing wire head of the outer sub-coil at the lowermost end is the tail of the high-voltage coil, and the outgoing wire heads of the remaining outer sub-coils and the outgoing wire heads of the corresponding inner sub-coils are connected by diagonal wires, so that the sub-coils are sequentially connected in the order of outer, inner and outer sub-coils, and the maximum voltage between adjacent sub-coils is not greater than 6000V. A winding method is also disclosed. After the above structure is adopted, the maximum voltage between adjacent sub-coils is low, and the production efficiency is high.

Description

Technical Field

[0001] This invention relates to a transformer coil, specifically a high-voltage coil of a dry-type transformer with an axial air passage and its winding method. Background Technology

[0002] Currently, the high-voltage coils of conventional resin-cast dry-type transformers are segmented cylindrical windings. To reduce partial discharge in the high-voltage coils, some dry-type transformers use continuously wound coils, such as the continuous high-voltage coil for a resin-cast dry-type transformer disclosed in Chinese Patent No. CN201210208419.7. This continuously wound coil comprises a set of continuously wound, parallel-connected discs arranged in a forward and reverse disc structure. Because this structure requires forward and reverse discs, an air channel cannot be placed in the middle, resulting in ineffective heat dissipation for the transformer. However, most large-capacity transformers require axial air channel cooling, which means this continuous coil structure cannot be applied to large-capacity dry-type transformers.

[0003] To address the aforementioned issues, Chinese patent application CN201720320411.8 discloses a dry-type transformer coil. This coil, resembling a disc, includes an inner coil and an outer coil, with a separator block between them to create a first air channel. The winding sequence of this disc coil is as follows: from the inner coil of the first disc coil to the inner coil of the last disc coil, and then from the outer coil of the first disc coil to the outer coil of the last disc coil. The disc coil is connected by a lead wire connecting the tail end of the inner coil of the first disc coil to the head end of the outer coil of the last disc coil. While this coil forms an axial air channel through the separator block, satisfying heat dissipation requirements, the head-to-tail connection between the inner and outer coils results in a maximum adjacent voltage difference of up to half the transformer's voltage rating. Therefore, an increased insulation distance is necessary, leading to a larger transformer size and higher cost. Furthermore, it prevents the production of higher voltage transformers and may pose quality risks. In addition, for insulation or heat dissipation, spacers are placed between adjacent disc coils in this continuous coil, which requires manual placement of spacers for each disc coil being wound, resulting in reduced production efficiency.

[0004] Therefore, further improvements are needed for the existing technology. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to propose a continuous high-voltage coil of a dry-type transformer with an axial air passage, which has a lower maximum voltage between adjacent sub-coils and higher production efficiency, in light of the above-mentioned technical status.

[0006] The second technical problem to be solved by the present invention is to propose a method for winding a continuous high-voltage coil of a dry-type transformer with an axial air passage, which is aimed at addressing the above-mentioned technical status quo. This method results in a lower maximum voltage between adjacent sub-coils in the wound high-voltage coil and improves production efficiency.

[0007] The technical solution adopted by the present invention to solve the first technical problem mentioned above is as follows: a continuous high-voltage coil of a dry-type transformer with an axial air passage, comprising a multi-panel coil and an axial air passage, characterized in that: the multi-panel coil is divided into multiple sub-coils, each sub-coil is wound continuously with only an outer insulated wire, the multiple sub-coils are further divided into n inner layer sub-coils and m outer layer sub-coils by the axial air passage, and an insulating element is provided between adjacent sub-coils in the inner and outer layer sub-coils; the upper and lower ends of each inner layer sub-coil are series-connected output terminals, and the m outer layer sub-coils are further divided into at least It includes the uppermost outer sub-coil and a tap section consisting of two outer sub-coils. The tap section has series output terminals at the upper and lower ends and multiple tap output terminals in the middle. The upper output terminal of the uppermost outer sub-coil becomes the beginning of the high-voltage coil, and the lower output terminal of the lowermost outer sub-coil becomes the end of the high-voltage coil. The output terminals of the remaining outer sub-coils are connected to the corresponding output terminals of the inner sub-coils by diagonal wires, so that the sub-coils are connected in series in the order of outer sub-coil, inner sub-coil, and outer sub-coil, so that the maximum voltage between adjacent sub-coils does not exceed 6000V.

[0008] Preferably, in the inner and outer sub-coils, the winding directions of adjacent disc coils between adjacent upper and lower sub-coils are opposite, so that the respective sub-coils in the inner and outer sub-coils can continue to be wound without reversing, thereby further improving production efficiency.

[0009] Preferably, by adjusting the number of turns of the corresponding disc coil in the outer sub-coil, each tap lead is located outside the corresponding disc coil of the corresponding outer sub-coil. This structure makes the tap lead extraction more convenient, the overall high-voltage coil more compact, and the cost lower.

[0010] Preferably, the number of turns of each disc coil in the inner sub-coil is 'a', and the number of turns of each disc coil in the outer sub-coil is 'b', where a:b = 4 / 6 - 3 / 7. This reasonable turns ratio facilitates heat dissipation of the high-voltage coil.

[0011] Preferably, the inner layer sub-coil is provided with an inner insulating layer on its inner side, and the outer layer sub-coil is provided with an outer insulating layer on its outer side, in order to improve the overall insulation performance.

[0012] Preferably, there are 6 sub-coils, wherein the number of inner sub-coils n=2 and the number of outer sub-coils m=4.

[0013] Preferably, there are 10 sub-coils, wherein the number of inner sub-coils n=4 and the number of outer sub-coils m=6.

[0014] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a method for winding a continuous high-voltage coil of a dry-type transformer with an axial air passage, characterized by comprising the following steps:

[0015] Step 1: The inner insulation layer is tightly wrapped around the coil mold;

[0016] Step 2: Wind the bottom inner sub-coil on the outer surface of the inner insulation layer using a continuous winding method, and reserve the top and bottom ends of the inner sub-coil as the lead wires for series connection; if n=1, proceed to step 4; if n is greater than or equal to 2, proceed to step 3.

[0017] Step 3: Place the insulating component on the upper surface of the lowest inner sub-coil. Repeat Step 2 on the insulating component and wind the remaining inner sub-coils from bottom to top until n inner sub-coils are completed. Reserve the upper and lower ends of each inner sub-coil as the lead wires for series connection.

[0018] Step 4: Wrap the outer surface of the wound inner sub-coil tightly with the first insulating tape, then place an air duct plate or air duct bar on the outside of the first insulating tape to form the axial channel, and then wrap the outside of the air duct plate or air duct bar with the second insulating tape.

[0019] Step 5: On the outside of the second insulating tape, the lowest outer sub-coil is wound in a continuous winding manner. After the winding is completed, the insulating component is placed on the upper surface of the lowest outer sub-coil.

[0020] Step 6: Repeat Step 5 on the insulating component, winding the remaining outer sub-coils sequentially from bottom to top until m outer sub-coils are completed; and reserve the upper end of the uppermost outer sub-coil to make it the beginning of the high-voltage coil; reserve the lower end of the lowermost outer sub-coil to make it the end of the high-voltage coil; at the same time, lead out the tap head at the corresponding part of the two outer sub-coils that serve as the tap section, and reserve the upper and lower ends of the tap section and the ends of the remaining outer sub-coils;

[0021] Step 7: Connect the output ends of each sub-coil in series in the order of outer sub-coil, inner sub-coil, and outer sub-coil using a tie wire.

[0022] Step 8: Secure the above-mentioned guy wire connections, beginning and end points, and branch wire ends with insulators.

[0023] Step 9: Wrap the outer insulation layer around the outer sub-coil as described above.

[0024] Compared with the prior art, the advantages of this invention are as follows: After the multi-panel coil of this invention is divided into multiple sub-coils, adjacent inner and outer sub-coils are separated by axial air channels, and adjacent upper and lower sub-coils are separated by insulating components. The axial air channels allow the heat generated by the panel coil during operation to be effectively and quickly dissipated, thereby improving the operational reliability and service life of the dry-type transformer coil. Simultaneously, there are no insulating pads between the panel coils within each sub-coil of this invention, thus eliminating the need for manual placement of pads during winding, significantly improving production efficiency. Furthermore, this invention improves the connection method between the inner and outer sub-coils. Regardless of the voltage level of the dry-type transformer, the maximum voltage difference between sections of the high-voltage coil wound using the method disclosed in this invention does not exceed 6000V, thus eliminating the need to increase the inter-section insulation distance, resulting in lower transformer partial discharge levels, lower costs, and fewer quality risks. In addition, the tap leads of this invention can be led out from the outside of the corresponding panel coil of the outer sub-coil, further improving the production efficiency of the high-voltage coil. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0029] Example 1

[0030] like Figure 1The diagram illustrates a continuous high-voltage coil for a dry-type transformer with an axial air duct. It includes a multi-panel coil and a single axial air duct 1. The multi-panel coil is divided into four sub-coils, each wound continuously with insulated wire. There are no insulating pads between adjacent panel coils. After the winding process described below is completed, the subsequent epoxy casting process will, as in existing technologies, involve infiltrating insulating materials such as epoxy resin and silicone rubber between adjacent panel coils. In this embodiment, the four sub-coils are further divided by the aforementioned axial air duct 1 into an inner sub-coil 2 and three outer sub-coils 3. The three outer sub-coils 3 are referred to from bottom to top as: the first outer sub-coil 31, the second outer sub-coil 32, and the third outer sub-coil 33. An insulating element 4 is provided between adjacent upper and lower sub-coils in the outer sub-coil 3, and the winding directions of adjacent panel coils between adjacent upper and lower sub-coils are opposite. In this embodiment, the number of turns of the inner sub-coil 2 and the outer sub-coil 3 is also optimized. The number of turns of each pancake coil of the inner sub-coil 2 is denoted as a, and the number of turns of each pancake coil of the outer sub-coil 3 is denoted as b. a:b = 4 / 6-3 / 7. Preferably, a:b = 4 / 6, or a:b = 3 / 7, etc.

[0031] After being divided into inner and outer sub-coils, the upper and lower ends of the inner sub-coil 2 are the lead-out terminals for series connection. Among the outer sub-coils 3, the uppermost outer sub-coil (i.e., the third outer sub-coil 33) has its upper lead-out terminal as the head 7 of the high-voltage coil, and the lower end of the third outer sub-coil 33 is the lower lead-out terminal for series connection. The remaining two outer sub-coils (from bottom to top, namely the first outer sub-coil 31 and the second outer sub-coil 32) form the tap section 5, which has lead-out terminals for series connection at the upper and lower ends and six tap-out terminals 6 in the middle. Specifically, the upper end of the second outer sub-coil 32 serves as the upper output terminal for series connection, and three upper tap wires 62 are led out from the corresponding position at the lower part of the second outer sub-coil 32; three lower tap wires 61 are led out from the corresponding position at the upper part of the first outer sub-coil 31, and the three upper tap wires 62 are located on the outside of the corresponding pancake coil of the second outer sub-coil 32, and the three lower tap wires 61 are similarly located on the outside of the corresponding pancake coil of the first outer sub-coil 31. The lower output terminal of the first outer sub-coil 31 then becomes the tail end 8 of the high-voltage coil. Then... The lead-out ends of the outer sub-coil and the lead-out ends of the inner sub-coil 2 are connected by a guy wire 9, so that the sub-coils are connected in series in the order of outer sub-coil, inner sub-coil, and outer sub-coil. Specifically, in this embodiment, from bottom to top, the upper lead-out end of the second outer sub-coil 32 is connected to the lower lead-out end of the inner sub-coil 2 through the first guy wire 91, and the upper lead-out end of the inner sub-coil 2 is connected to the lower lead-out end of the third outer sub-coil 33 through the second guy wire 92, so that the maximum voltage between adjacent sub-coils is not greater than 6000V. That is, the maximum voltage between the first outer sub-coil 31 and the inner sub-coil 2, between the second outer sub-coil 32 and the inner sub-coil 2, between the third outer sub-coil 33 and the inner sub-coil 2, and between the second outer sub-coil 32 and the third outer sub-coil 33 is not greater than 6000V.

[0032] Considering the insulation performance of the inner side, an inner insulation layer (not shown in the figure) is also provided on the inner side of the inner sub-coil 2, and an outer insulation layer is also provided on the outer side of the outer sub-coil 3. In this embodiment, the inner and outer insulation layers can specifically be insulating mesh cloth of the required quantity and specifications, and glass cloth tape wrapped around the outer surface of the mesh cloth.

[0033] The high-voltage coil winding method in this embodiment includes the following steps:

[0034] Step 1: Tightly wrap the inner insulation layer on the coil mold. Specifically, first tightly wrap the required quantity and specifications of insulating mesh cloth on the coil mold, and then wrap the outer surface of the insulating mesh cloth with glass cloth tape to ensure that the insulating mesh cloth is tight and the surface is smooth.

[0035] Step 2: The inner layer sub-coil 2 is wound continuously on the outer surface of the inner insulation layer, and the upper and lower ends of the inner layer sub-coil 2 are reserved as lead-out ends for series connection.

[0036] Step 3: Tightly wrap the outer surface of the wound inner layer sub-coil 2 with the first insulating tape; then place an air duct plate or air duct rod on the outside of the first insulating tape. The air duct plate or air duct rod can be formed using existing technology to create an axial channel; then wrap the outside of the air duct plate or air duct rod with the second insulating tape. Here, the first and second insulating tapes can be wrapped with insulating mesh cloth first, and then tied tightly with glass cloth tape, using a combination of the two materials to wrap securely.

[0037] Step 4: On the outside of the second insulating tape, the first outer sub-coil 31 is wound continuously. The lower end of the first outer sub-coil 31 is reserved so that it becomes the tail 8 of the high-voltage coil, that is, an external lead of the high-voltage coil, which serves as the x (or y or z) external lead. At the same time, three lower branch wires 61 are led out from the corresponding part of the upper part of the first outer sub-coil 31. After the winding is completed, an insulating component 4 is placed on the upper surface of the first outer sub-coil 31. For distinction, the insulating component placed on the first outer sub-coil 31 is called the first insulating component 41. The first insulating component 41 can be made of insulating materials in the prior art, specifically mesh cloth or molded epoxy resin pad.

[0038] Step 5: Continue winding the second outer sub-coil 32 from bottom to top on the first insulating member 41 using a continuous winding method. Three upper tap leads 62 are led out from the corresponding lower part of the second outer sub-coil 32. These three upper tap leads 62 and the aforementioned three lower tap leads 61 form the six tap leads 6 of this high-voltage coil. The upper end of the second outer sub-coil 32 is reserved to serve as an upper tap for connection with the lower tap of the inner sub-coil 2. Then place the second... The insulating component 42 continues to wind the third outer sub-coil 33 using a continuous winding method, reserving the lower end of the third outer sub-coil 33 so that it can serve as the lower lead of the third outer sub-coil 33, facilitating connection with the upper lead of the inner sub-coil 2; until the third outer sub-coil 33 is completed, and the upper end of the third outer sub-coil 3 is reserved so that it becomes the head 7 of the high-voltage coil, that is, another external lead of the high-voltage coil, which can serve as the external lead of phase A (or phase B or phase C);

[0039] Step 6: Using the diagonal guy wire 9, connect the leads of each sub-coil in the order of outer layer sub-coil, inner layer sub-coil, and outer layer sub-coil. Figure 1As shown, the coils can be connected sequentially, from top to bottom. The lower lead of the third outer sub-coil 33 can be connected to the upper lead of the inner sub-coil 2 via the second guy wire 92, and the lower lead of the inner sub-coil 2 can be connected to the upper lead of the second outer sub-coil 32 via the first guy wire 91. Of course, depending on the needs, the connection can also be made from bottom to top, as long as the order of outer sub-coil, inner sub-coil, and outer sub-coil is followed.

[0040] Step 7: At the connection points of the first guy wire 91 and the second guy wire 92, at the beginning 7 and the end 8, and at the branch wire end 6, respectively, an insulator (using existing technology) is used to wrap the wires. Then, according to existing technology, an outer insulation layer is wrapped around the three outer coils 3. This outer insulation layer can be made of insulating mesh cloth and glass cloth tape tightly wrapped around the insulating mesh cloth to obtain the required high-voltage coil.

[0041] Using the high-voltage coil with the above structure and its winding method, when the voltage of the high-voltage coil is 10KV, taking the above four sub-coils as an example, the voltage distribution is as follows: the third outer sub-coil 33 is 1250V, the inner sub-coil 2 is 5000V, the second outer sub-coil 32 is 1250V, and the first outer sub-coil 32 is 2500V. Thus, the voltage difference between the third outer sub-coil 33 and the inner sub-coil 2 is 1250V, the voltage difference between the inner sub-coil 2 and the second outer sub-coil 32 is less than 3750V, the voltage difference between the third outer sub-coil 33 and the second outer sub-coil 32 is 5000V, and the voltage difference between the inner sub-coil 2 and the first outer sub-coil 31 is 3750V. Therefore, in this embodiment, the maximum voltage difference between adjacent sub-coils is 5000V.

[0042] Example 2

[0043] The difference between this embodiment and Embodiment 1 is that the number of sub-coils is six, and their specific structure and connection method are as follows: Figure 2 As shown, the number of inner sub-coils 2 is n=2, and they are referred to as the first inner sub-coil 21 and the second inner sub-coil 22 from bottom to top; the number of outer sub-coils 3 is m=4, and they are referred to as the first outer sub-coil 31, the second outer sub-coil 32, the third outer sub-coil 33 and the fourth outer sub-coil 34 from bottom to top.

[0044] The high-voltage coil winding method in this embodiment includes the following steps:

[0045] Step 1: Tightly wrap the inner insulation layer onto the coil mold. The material of the inner insulation layer can be the material described in the first embodiment, or other materials in the prior art.

[0046] Step 2: The first inner layer sub-coil 21 is wound continuously on the outer surface of the inner insulation layer, and the upper and lower ends of the first inner layer sub-coil 21 are reserved as lead wires for series connection.

[0047] Step 3: Place an insulating component 4 (the specific material can be the same as in Embodiment 1 above) on the upper surface of the first inner layer sub-coil 21. Repeat step 2 on the insulating component 4 and wind the second inner layer sub-coil 22 from bottom to top until the second inner layer sub-coil 22 is completed. Reserve the upper and lower ends of the second inner layer sub-coil 22 as lead wires for series connection.

[0048] Step 4: Wrap the outer surfaces of the wound first inner layer sub-coil 21 and the second inner layer sub-coil 22 tightly with the first insulating tape as described above, then place an air duct plate or air duct bar on the outside of the first insulating tape to form an axial channel, and then wrap the same second insulating tape on the outside of the air duct plate or air duct bar.

[0049] Step 5: On the outside of the second insulating tape, the first outer sub-coil 31 is wound continuously. After the winding is completed, the upper and lower ends of the first outer sub-coil 31 are reserved. The lower end of the first outer sub-coil 31 is used as the tail end 8 of the high voltage coil. The lower end of the first outer sub-coil 31 is used as the upper lead end for series connection. Then, an insulating component 4 is placed on the upper surface of the first outer sub-coil 31. In order to distinguish them, the insulating components between adjacent outer sub-coils are called the first insulating component 41, the second insulating component 42 and the third insulating component 43 from bottom to top. That is, the insulating component placed on the first outer sub-coil 31 is called the first insulating component 41.

[0050] Step 6: Repeat step 5 on the first insulating member 41, and wind the remaining outer sub-coils 3 sequentially from bottom to top, that is, wind the second outer sub-coil 32, place the second insulating member 42, wind the third outer sub-coil 33, place the third insulating member 43, and wind the fourth outer sub-coil 34 in sequence until four outer sub-coils 3 are completed; and reserve the upper end of the fourth outer sub-coil 34 so that it becomes the head 7 of the high-voltage coil; at the same time, three lower branch wires 61 are led out from the corresponding part of the upper part of the second outer sub-coil 32, and three upper branch wires 62 are led out from the corresponding part of the lower part of the third outer sub-coil 33, and reserve the lower branch wires of the second outer sub-coil 32, the upper branch wires of the third outer sub-coil 33, and the lower branch wires of the fourth outer sub-coil 34;

[0051] Step 7: Using the diagonal guy wire 9, connect the leads of each sub-coil in the order of outer sub-coil 3, inner sub-coil 2, and outer sub-coil 3. Figure 2As shown, they are connected in series. Specifically, from bottom to top, the upper output of the first outer sub-coil 31 is connected to the lower output of the first inner sub-coil 21 through the first inclined wire 91. The upper output of the first inner sub-coil 21 is connected to the lower output of the second outer sub-coil 32 through the second inclined wire 92. The upper output of the third outer sub-coil 33 is connected to the lower output of the second outer sub-coil 2 through the third inclined wire 93. The upper output of the second outer sub-coil 2 is connected to the lower output of the fourth outer sub-coil 34 through the fourth inclined wire 94.

[0052] Step 8: At the connection points of the above-mentioned guy wires 9 (i.e., the first, second, third, and fourth guy wires), the beginning 7 and the end 8, and the branch wire end 6, respectively, an insulator is wrapped. Then, according to existing technology, an outer insulation layer is wrapped around the four outer coils 3. This outer insulation layer is also made of insulating mesh cloth and glass cloth tape tightly wrapped around the insulating mesh cloth, thus obtaining the required high-voltage coil.

[0053] Using the high-voltage coil of this embodiment, when its voltage level is 10KV, taking the above six sub-coils as an example, the voltage distribution is as follows: the voltage of the first inner sub-coil 21 is 2500V, the voltage of the second inner sub-coil 22 is 2500V, the voltage of the first outer sub-coil 31 is 1250V, the voltage of the second outer sub-coil 32 is 1250V, the voltage of the third outer sub-coil 33 is 1250V, and the voltage of the fourth outer sub-coil 34 is 1250V. Thus, the voltage difference between the first outer sub-coil 31 and the first inner sub-coil 21 is 1250V, the voltage difference between the first outer sub-coil 31 and the second outer sub-coil 32 is less than 2500V, and the voltage difference between the first inner sub-coil 21 and the second outer sub-coil 32 is 1250V. Obviously, in this embodiment, the maximum voltage difference between adjacent sub-coils is 2500V.

[0054] Example 3

[0055] The difference between this embodiment and Embodiment 2 is that there are ten sub-coils, and their specific structure and connection method are as follows: Figure 3 As shown, the number of inner sub-coils 2 is n=4, and from bottom to top they are called the first inner sub-coil 21, the second inner sub-coil 22, the third inner sub-coil 23 and the fourth inner sub-coil 24, respectively. The number of outer sub-coils 3 is m=6, and from bottom to top they are called the first outer sub-coil 31, the second outer sub-coil 32, the third outer sub-coil 33, the fourth outer sub-coil 34, the fifth outer sub-coil 35 and the fifth outer sub-coil 36, respectively.

[0056] The lower output of the first outer sub-coil 31 is also the tail end 8 of the high-voltage coil. The upper output of the first outer sub-coil 31 is connected to the lower output of the first inner sub-coil 21 via the first guy wire 91. The upper output of the first inner sub-coil 21 is connected to the lower output of the second outer sub-coil 32 via the second guy wire 92. The upper output of the second outer sub-coil 32 is connected to the lower output of the second inner sub-coil 22 via the third guy wire 93. The upper output of the second inner sub-coil 22 is connected to the lower output of the third outer sub-coil 33 via the fourth guy wire 94. Three lower branch outputs 6 are led out from the corresponding positions on the upper part of the third outer sub-coil 33. 1. Three upper taps 62 are led out from the corresponding positions below the fourth outer sub-coil 34. The upper tap of the fourth outer sub-coil 34 is connected to the lower tap of the third inner sub-coil 23 via the fifth guy wire 95. The upper tap of the third inner sub-coil 23 is connected to the lower tap of the fifth outer sub-coil 35 via the sixth guy wire 96. The upper tap of the fifth outer sub-coil 35 is connected to the lower tap of the fourth inner sub-coil 24 via the seventh guy wire 97. The upper tap of the fourth inner sub-coil 24 is connected to the lower tap of the sixth outer sub-coil 36 via the eighth guy wire 98. The upper tap of the sixth outer sub-coil 36 serves as the starting end 7 of the high-voltage coil. Similarly, in the inner and outer sub-coils, insulating components 4 are provided in adjacent upper and lower sub-coils, specifically, as shown in... Figure 3 In the inner sub-coil, there are three insulating components 4 from bottom to top, and in the outer sub-coil, there are five insulating components from bottom to top. Their specific numbers are not distinguished.

[0057] The specific winding method will not be described in detail.

[0058] Using more sub-coils allows for higher voltage levels in the high-voltage coil. Furthermore, the number of axial air passages can be increased as needed, distributed radially at intervals. In this case, for the same axial air passage, the sub-coils located on either side are the inner and outer sub-coils, thus improving heat dissipation for higher voltage-level high-voltage coils.

[0059] Using the high-voltage coil in this embodiment, when its voltage level is 35KV, taking the above ten sub-coils as an example, the voltage distribution is as follows: the voltage of the first inner sub-coil 21 is 3750V, the voltage of the second inner sub-coil 22 is 5000V, the voltage of the third inner sub-coil 23 is 5000V, the voltage of the fourth inner sub-coil 24 is 3750V, the voltage of the first outer sub-coil 31 is 3500V, the voltage of the second outer sub-coil 32 is 3000V, the voltage of the third outer sub-coil 33 is 2000V, the voltage of the fourth outer sub-coil 34 is 3000V, and the voltage of the fifth outer sub-coil 35 is 2000V. The voltage of the sixth outer sub-coil 36 is 3500V. Thus, the voltage difference between the first outer sub-coil 31 and the first inner sub-coil 21 is 3750V, the voltage difference between the first outer sub-coil 31 and the second outer sub-coil 32 is 3750V, the voltage difference between the second inner sub-coil 22 and the second outer sub-coil 32 is 3000V, the voltage difference between the second outer sub-coil 32 and the third outer sub-coil 33 is 5000V, and the voltage difference between the second inner sub-coil 22 and the third inner sub-coil 23 is 4000V. Obviously, in this embodiment, the maximum voltage difference between adjacent sub-coils is 5000V.

[0060] In addition to the preferred embodiments described above, the number of sub-coils can also be selected from other numbers, such as three, five, or eight, which can be selected according to the voltage level of the high-voltage transformer coil. Therefore, such a scheme also falls within the protection scope of this invention.

Claims

1. A continuous high-voltage coil of a dry-type transformer with an axial air passage, comprising a multi-panel coil and an axial air passage (1), characterized in that: The multi-pancake coil is divided into multiple sub-coils, each of which is wound in a continuous structure using only insulated wire. These multiple sub-coils are further separated by the axial air passage (1). n The inner sub-coil (2) and m Each outer sub-coil (3) has an insulating element (4) between adjacent sub-coils in the inner and outer sub-coils (2, 3); the upper and lower ends of each inner sub-coil (2) are lead-out terminals for series connection. m Each outer sub-coil (3) includes at least the uppermost outer sub-coil (3) and a tap section (5) composed of two outer sub-coils (3). The tap section (5) is provided with series output terminals at the upper and lower ends and multiple tap output terminals (6) in the middle. The upper output terminal of the uppermost outer sub-coil (3) becomes the head (7) of the high-voltage coil, and the lower output terminal of the lowermost outer sub-coil (3) becomes the tail (8) of the high-voltage coil. The output terminals of the remaining outer sub-coils (3) and the output terminals of the corresponding inner sub-coils (2) are connected by a tie wire (9) so that each sub-coil is connected in series in the order of outer sub-coil (3), inner sub-coil (2), and outer sub-coil (3) so that the maximum voltage between adjacent sub-coils is not greater than 6000V. The number of turns of each disc coil in each inner sub-coil (2) is a The number of turns of each disc coil in each of the outer sub-coils (3) is b , a : b =4 / 6 - 3 / 7.

2. The continuous high-voltage coil of a dry-type transformer with an axial air passage according to claim 1, characterized in that: In the inner and outer sub-coils (2, 3), the winding directions of adjacent disc coils between adjacent upper and lower sub-coils are opposite.

3. The continuous high-voltage coil of a dry-type transformer with an axial air passage according to claim 1, characterized in that: Each of the aforementioned taps (6) is located on the outside of the corresponding pancake coil of the corresponding outer sub-coil (3).

4. The continuous high-voltage coil of a dry-type transformer with an axial air passage according to claim 1, characterized in that: The inner layer sub-coil (2) is provided with an inner insulating layer on its inner side, and the outer layer sub-coil (3) is provided with an outer insulating layer on its outer side.

5. The continuous high-voltage coil of a dry-type transformer with an axial air passage according to claim 1, characterized in that: The number of sub-coils is 6, wherein the number of inner layer sub-coils (2) is... n =2, the number of outer sub-coils (3) m =4.

6. The continuous high-voltage coil of a dry-type transformer with an axial air passage according to claim 1, characterized in that: The number of sub-coils is 10, wherein the number of inner layer sub-coils (2) is... n =4, the number of outer sub-coils (3) m =6.

7. A method for winding a continuous high-voltage coil of a dry-type transformer with an axial air passage as described in claim 4, characterized in that, Includes the following steps: Step 1: The inner insulation layer is tightly wrapped around the coil mold; Step 2: The lowest inner layer sub-coil (2) is wound continuously around the outer surface of the inner insulation layer, and the upper and lower ends of the lowest inner layer sub-coil are reserved for use as lead-out terminals in series. n If = 1, proceed to step 4; if n If the value is greater than or equal to 2, proceed to step 3; Step 3: Place the insulating member (4) on the upper surface of the lowest inner sub-coil (2), and repeat Step 2 on the insulating member (4) to wind the remaining inner sub-coils (2) from bottom to top until completion. n Each inner sub-coil (2) is provided, and the upper and lower ends of each inner sub-coil (2) are reserved as the output terminals for series connection. Step 4: Wrap the outer surface of the wound inner sub-coil (2) tightly with the first insulating cloth tape, and then place an air duct plate or air duct bar on the outer surface of the first insulating cloth tape to form the axial channel. Then wrap the outer surface of the air duct plate or air duct bar with the second insulating cloth tape. Step 5: The outermost sub-coil (3) is wound continuously on the outside of the second insulating tape. After the winding is completed, the insulating component (4) is placed on the upper surface of the outermost sub-coil (3). Step 6: Repeat step 5 on the insulating member (4) to wind the remaining outer sub-coils (3) from bottom to top until completion. m The outer sub-coil (3) is prepared; the upper end of the uppermost outer sub-coil (3) is reserved to make it the beginning (7) of the high voltage coil; the lower end of the lowermost outer sub-coil (3) is reserved to make it the end (8) of the high voltage coil; at the same time, the tap-out wires (6) are led out at the corresponding parts of the two outer sub-coils (3) that serve as tap sections (5), and the upper and lower ends of the tap section (5) and the remaining outer sub-coils (3) are reserved; Step 7: Connect the output ends of each sub-coil in series in the order of outer sub-coil (3), inner sub-coil (2), and outer sub-coil (3) using a tie wire (9); Step 8: Wrap and fix the above-mentioned guy wires (9) at the connection point, the first end (7) and the last end (8) and the branch wire end (6) with an insulator; Step 9: Wrap the outer insulation layer around the outer sub-coil (3) as described above.

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