Transformer using composite conductor coil and method for connecting composite conductor

Abstract

The application discloses a transformer adopting a composite conductor coil and a connecting method of the composite conductor, and relates to the technical field of transformers, in particular to a transformer adopting a composite conductor coil, which comprises a core column and a coil wound on the core column, wherein the coil comprises, from top to bottom, an upper coil, a middle coil electrically connected with the upper coil and a lower coil electrically connected with the middle coil; the upper coil and the lower coil are formed by winding a first conductor; the middle coil is formed by winding a second conductor; the first conductor is a composite conductor comprising a plurality of sub-conductors; the second conductor is a composite conductor comprising a plurality of sub-conductors; and the number of the sub-conductors of the first conductor is greater than that of the second conductor. The application adopts multiple composite conductors at the two ends of the coil and two composite conductors at the middle part of the coil, so that the problem of increased eddy current loss and temperature rise caused by the magnetic field bending of the coil end can be solved, and the production cost is controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of transformer, in particular to a transformer adopting a composite conductor coil and a connecting method of the composite conductor. BACKGROUND

[0002] In high-voltage, super-high-voltage and extra-high-voltage AC-DC transformers, ordinary conductors are generally used for winding, and the ordinary conductors are generally single conductors. According to the magnetic effect of electric current, that is, if a metal conductor passes through an electric current, a circular magnetic field will be generated around the conductor, and the greater the electric current flowing through the conductor, the stronger the magnetic field generated. After being electrified, the cross section of the single conductor is relatively thick, and the electric current flowing through the conductor is relatively large, which will cause the magnetic field generated by the conductor to be relatively strong. Since the magnetic field at the end of the coil will be bent, the magnetic field of the ordinary conductor at the end of the coil will increase the eddy current loss, and at the same time, the conductor will heat up, which will cause safety hazards.

[0003] In view of the above problems, a composite conductor is disclosed in Chinese patent CN2914275Y. In this patent, it is proposed that the magnetic field positions of the parallel sub-conductors in the composite conductor are the same, and the electric current in the single conductor is relatively small, which generates a relatively small magnetic field and reduces the magnetic leakage loss. That is, the composite conductor is used to wind the transformer coil, which can reduce the eddy current loss of the coil in the end magnetic field and improve the temperature rise phenomenon at the end of the transformer coil.

[0004] According to the above principle, the more the number of sub-conductors of the composite conductor, the better the improvement effect on the coil end eddy current loss and temperature rise phenomenon. However, a large number of conductors are required to wind the coil, and if the composite conductor with a large number of sub-conductors is used to wind the coil, the cost will be greatly increased. However, if a small number of sub-conductors are used to wind the coil, compared with the traditional single conductor, the problem of magnetic field bending in the coil end magnetic field cannot be fundamentally solved, and there is still a lot of eddy current loss. SUMMARY

[0005] In order to overcome the defects of large eddy current loss of ordinary conductors at the end of the coil and high cost of composite conductors in the prior art, the present application provides a transformer adopting a composite conductor coil and a connecting method of the composite conductor.

[0006] The embodiment of the application discloses a transformer adopting a composite conductor coil, which comprises a core column and a coil wound on the core column, wherein the coil comprises, from top to bottom, an upper section coil, a middle section coil electrically connected with the upper section coil and a lower section coil electrically connected with the middle section coil; the upper section coil and the lower section coil are formed by winding a first conductor; the middle section coil is formed by winding a second conductor; the first conductor is a composite conductor comprising a plurality of sub-conductors; the second conductor is a composite conductor comprising a plurality of sub-conductors; and the number of the sub-conductors of the first conductor is greater than that of the second conductor.

[0007] Preferably, the first conductor is a composite conductor comprising four sub-conductors, and the second conductor is a composite conductor comprising two sub-conductors.

[0008] Preferably, the first conductor is an axial four-composite conductor, and the second conductor is a radial two-composite conductor.

[0009] Preferably, the number of turns of the upper section coil accounts for 5%-6% of the total number of turns of the coil, and the number of turns of the upper section coil is equal to that of the lower section coil.

[0010] The application further discloses a connection method of the first conductor and the second conductor in the coil, which comprises the following steps.

[0011] S1: head correction, in which the sub-conductors of the first conductor to be welded are subjected to head correction, and the sub-conductors of the second conductor to be welded are subjected to head correction;

[0012] S2: conductor grouping, in which the sub-conductors in the first conductor are divided into a plurality of axial sub-conductor groups, and the sub-conductors in the second conductor are divided into a plurality of radial sub-conductor groups, and the axial sub-conductor groups and the radial sub-conductor groups are one-to-one corresponding to be welded;

[0013] S3: pressing a welding surface, in which a mold is used to press the sub-conductors, so that the welding surfaces of the corresponding axial sub-conductor groups and radial sub-conductor groups are the same;

[0014] S4: welding, in which the corresponding axial sub-conductor groups and radial sub-conductor groups are welded by using a high-frequency welding butt welding process;

[0015] S5: cleaning and insulation, in which the welding positions of the groups are cleaned and insulated, and finally the connection of the first conductor and the second conductor is completed.

[0016] Preferably, the head correction in step S1 is processed by using a flat mouthed force pliers.

[0017] Preferably, the high-frequency welding butt welding of step S4 specifically comprises the following steps: a silver solder sheet is arranged between the welding surfaces of the axial sub-conductor groups and the radial sub-conductor groups, and the two are welded by using a high-frequency welding machine.

[0018] Preferably, the gap between the axial sub-conductor group and the radial sub-conductor group is 0.2mm-0.5mm.

[0019] Preferably, the cleaning in step S5 refers to removing the oxide layer and sharp corners on the welding surface, and passivating the edges.

[0020] Preferably, the insulation in step S5 refers to using crinkled paper to cover, specifically including using crinkled paper to cover two layers of the welding surface of the axial sub-conductor group and the second sub-conductor, and after completing the welding and cleaning of each group, using crinkled paper to cover four layers of the welding surface of the combined groups.

[0021] The present application has at least the following beneficial effects:

[0022] The present application uses multiple composite conductors at both ends of the coil and two composite conductors in the middle of the coil, which can improve the problem of increased eddy current loss and temperature rise caused by the bending of the magnetic field at the end of the coil, while controlling the production cost. When changing the wire, the present application presses and forms the sub-conductor connection part to ensure that the cross section of the sub-conductor and the second sub-conductor connection part matches, the electrode shape is good, and then uses a flat mouthed pliers to correct the axial composite and second sub-conductor to be connected, and then uses high frequency welding butt welding process to weld them, which not only ensures the contact area of the two types of conductors, but also ensures the strength of the connection of the two sub-conductors and the second sub-conductor.

[0023] In order to make the above and other objects, features and advantages of the present application more apparent, the following will describe a preferred embodiment, and the accompanying drawings will be described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0025] Figure 1 is a structural schematic diagram of the coil in the embodiment of the present application;

[0026] Figure 2 is a structural schematic diagram of the first conductor, i.e. the axial four composite conductor in the embodiment of the present application;

[0027] Figure 3 is a cross-sectional schematic diagram of the first conductor, i.e. the axial four composite conductor in the embodiment of the present application;

[0028] Figure 4is a schematic view of the structure of the second wire, that is, the radial two composite wires in the embodiment of the present application;

[0029] Figure 5 is a schematic view of the cross section of the second wire, that is, the radial two composite wires in the embodiment of the present application;

[0030] Figure 6 (a) in is a schematic view of the structure of the welding surface of the first wire in the embodiment of the present application, Figure 6 (b) in is a schematic view of the structure of the welding surface of the second wire in the embodiment of the present application;

[0031] Figure 7 is a schematic view of the connection of an axial sub-wire group and a radial sub-wire group of a transformer using a composite wire coil in the embodiment of the present application.

[0032] The reference signs of the above drawings are as follows: 01, upper coil; 02, middle coil; 03, lower coil; 10, first wire; 101, sub-wire of the first wire; 11, first axial sub-wire group; 12, second axial sub-wire group; 20, second wire; 201, sub-wire of the second wire; 21, first radial sub-wire group; 22, second radial sub-wire group. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] A transformer using a composite wire coil, wherein it comprises a core column and a coil wound on the core column, as shown in Figure 1 The coil comprises, from top to bottom, an upper coil 01, a middle coil 02 electrically connected with the upper coil 01, and a lower coil 03 electrically connected with the middle coil 02.

[0035] Referring to Figure 1 and Figure 2 The upper coil 01 and the lower coil 03 are wound by a first wire 10, and the first wire 10 is a composite wire comprising a plurality of sub-wires, referring to Figure 1 and Figure 4 The middle coil 02 is wound by a second wire 20, and the second wire 20 is a composite wire comprising a plurality of sub-wires, and the number of the sub-wires of the first wire 10 is greater than that of the second wire 20.

[0036] The transformer in the application adopts composite wires to wind coils, so as to improve eddy current loss and temperature rise phenomenon and reduce negative effects caused by coil end leakage magnetic field.

[0037] Different composite wires are selected according to magnetic field requirements at different parts of the coil, so that on the one hand, the eddy current loss of the two ends of the coil can be improved, and the temperature rise phenomenon can be inhibited, and on the other hand, since the number of sub-wires of the second wire 20 is less than that of the first wire 10, the production cost and processing cost of the second wire 20 are lower than those of the first wire 10. In the embodiment of the application, the middle coil 02 with less eddy current loss is adopted to use the second wire 20 to control the cost of production.

[0038] As shown in the figure, Figures 2-3 In the application, the first wire 10 is an axial four composite wire including four sub-wires 101, and the wire specification that can be selected is: Axial four composite wire.

[0039] As shown in the figure, Figures 4-5 The second wire 20 is a radial two composite wire including two sub-wires 201, and the wire specification that can be selected is: Radial two composite wire.

[0040] According to the magnetic field simulation analysis, when the composite wire at the end of the coil is the axial four composite wire 10, the requirement of improving the leakage magnetic field at the end of the magnetic field can be met, and the eddy current loss can be effectively reduced.

[0041] According to the wire specification of the two composite wires, it is obvious that the cross section of the sub-wire 101 of the axial four composite wire can be matched with the cross section of the sub-wire 201 of the radial two composite wire. The middle coil 02 adopts the two composite wire with lower cost, the upper coil 01 and the lower coil 03 adopt the four composite wire, which can meet the requirements of improving the leakage magnetic field and the eddy current loss, and the cost is not high compared with the composite wire with more sub-wires, so the comprehensive cost performance is the best.

[0042] According to the axial four composite wire 10 and the radial two composite wire 20, the magnetic field simulation of the end of the transformer coil is performed, when the number of turns of the upper coil 01 accounts for 5%-6% of the total number of turns of the coil, and the number of turns of the upper coil 01 is equal to the number of turns of the lower coil 03, the cost performance of the product is the highest. Here, the ratio is the ratio of the number of turns, when the winding mode of each part of the coil is the same, the height of the coil with equal number of turns is equal, so in the application, the ratio of the current wire can be directly calculated by height. For example, when the winding height of the first wire 10 is 0.05-0.06 meters, it can be regarded as that the ratio of the first wire 10 is 5%-6%, that is, the ratio of the first wire 10 is 5%-6%.

[0043] In the process of the line changing connection of the first wire 10 and the second wire 20, if the connection mode is improper, the local overheating condition is prone to occur. Therefore, the application further provides a connection method of the composite wire.

[0044] The connection method of the first wire 10 and the second wire 20 in the coil comprises the following steps:

[0045] S1: head correction: the sub-wire 101 of the first wire to be welded is subjected to head correction, and the sub-wire 201 of the second wire to be welded is subjected to head correction.

[0046] Here, the flat mouthed force pliers are mainly used to perform head correction on the welding points of the sub-wire 101 in the first wire and the sub-wire 201 in the second wire. Since the end port surface of the special flat mouthed force pliers is perpendicular to the winding direction of the wire after the end port surface of the special flat mouthed force pliers is processed, the processed end port surface basically does not need to be corrected again, the operation is simple, and the pollution caused by the correction can be reduced to the minimum.

[0047] S2: wire grouping: the sub-wire 101 in the first wire is evenly divided into a plurality of axial sub-wire groups, the sub-wire 201 in the second wire is evenly divided into a plurality of radial sub-wire groups, and the axial sub-wire groups and the radial sub-wire groups are one-to-one corresponding to be welded.

[0048] Since the first wire 10 is an axial four-composite wire, and the second wire 20 is a radial two-composite wire, the axial sub-wire groups and the radial sub-wire groups are each two groups, as shown in Figure 3 As shown in Figure 5 , the left sub-wire in the second wire 20 is the first radial sub-wire group 21, and the right sub-wire is the second radial sub-wire group 22.

[0049] S3: pressing the welding surface: using a mold to press the sub-wire, so that the welding surfaces of the corresponding axial sub-wire groups and radial sub-wire groups are the same.

[0050] As shown in Figure 6 , the sub-wires in the first axial sub-wire group 11 are pressed and then combined using a mold, and the welding surface of the combined sub-wires is the same as the welding surface of the first radial sub-wire group 21, Figure 6 (a) of the figure is the welding surface of the axial composite wire after the pressing is completed, Figure 6Figure (b) shows the welding surface of the radial composite conductor. Specifically, taking the first axial sub-conductor group 11 and the first radial sub-conductor group 21 as examples, the cross-sectional width of one sub-conductor in the first axial sub-conductor group 11 is equal to the cross-sectional width of the sub-conductor in the first radial sub-conductor group 21, and its length is half the cross-sectional length of the sub-conductor in the first radial sub-conductor group 21. The welding surfaces of other axial sub-conductor groups and their corresponding radial sub-conductor groups are the same.

[0051] S4: Welding: The corresponding axial sub-conductor groups and radial sub-conductor groups are welded one by one using high-frequency welding butt welding process.

[0052] Specifically, refer to Figure 7 As shown in the figure, the butt welding of the first axial sub-conductor group 11 and the first radial sub-conductor group 21 is illustrated. The high-frequency butt welding specifically includes the following steps: The axial sub-conductor group and the corresponding radial sub-conductor group to be butt welded are clamped tightly with two pairs of pliers, while simultaneously being positioned; a gap of 0.2mm-0.5mm is left between the welding surfaces of the axial and radial sub-conductor groups, and a silver solder sheet of appropriate size is placed within the gap. The two are then welded using a high-frequency welding machine. The welding method for other axial sub-conductor groups and their corresponding radial sub-conductor groups is the same, ultimately completing the welding between the first conductor 10 and the second conductor 20.

[0053] S5: Cleaning and Insulation: Clean and insulate each weld joint to finally complete the connection between the first and second conductors.

[0054] Cleaning mainly involves removing the oxide layer and sharp corners from the welded surfaces, as well as passivating the edges.

[0055] The insulation mainly uses crepe paper wrapping, specifically including wrapping two layers of crepe paper at the welding joint of the axial sub-conductor group and the second sub-conductor, and after completing the welding and cleaning of each group, wrapping four layers of crepe paper at the conductor connection joint after merging the groups.

[0056] It should be noted that each of the sub-conductors in this invention is pre-insulated with matching turns.

[0057] In summary, the coil of the application is wound by composite wires, the middle coil is wound by two composite wires, and the upper and lower coils are wound by four composite wires, which can improve the problem of increased eddy current loss and temperature rise caused by the magnetic field bending of the coil end, and at the same time, the production cost is controlled, and the cost performance is high. When changing the wire, the flat-nose pliers are used to correct the axial composite and the second sub-wire to be connected respectively, the axial sub-wire group is pressed and formed, and the cross section of the connection part of the axial sub-wire group and the radial sub-wire group is matched, the electrode shape is good, then the high-frequency welding butt welding process is used for welding, which not only ensures that the contact area of the two kinds of wires is equal, but also ensures the strength of the connection between the two kinds of composite wires. The structure is suitable for the connection of composite wires for all high-voltage, super-high-voltage, extra-high-voltage AC and DC power transmission transformers, reactors and other large equipment.

[0058] The principles and implementation manners of the present application are described by using specific embodiments, and the above embodiment is only used to help understand the method and the core idea of the present application; meanwhile, for the general skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application, and the above description should not be understood as the limitation of the present application.

Claims

1. A transformer employing a composite conductor coil, characterized in that, include: The core column and the coil wound on the core column, wherein the coil, from top to bottom, includes an upper section coil, a middle section coil electrically connected to the upper section coil, and a lower section coil electrically connected to the middle section coil. The upper section coil and the lower section coil are formed by winding a first wire, and the middle section coil is formed by winding a second wire. The first wire is a composite wire including a plurality of sub-wires, and the second wire is a composite wire including a plurality of sub-wires. The number of sub-wires in the first wire is greater than the number of sub-wires in the second wire. The first conductor is a composite conductor comprising four sub-conductors, and the second conductor is a composite conductor comprising two sub-conductors; the first conductor is an axial four-composite conductor, and the second conductor is a radial two-composite conductor. The method for connecting the first and second conductors includes the following steps: S1: Trimming: Trimming the sub-wires of the first wire to be soldered and trimming the sub-wires of the second wire to be soldered; S2: Wire grouping: Divide the sub-wires in the first wire into several axial sub-wire groups, and divide the sub-wires in the second wire into several radial sub-wire groups. The axial sub-wire groups and radial sub-wire groups correspond one-to-one and are to be welded. S3: Press welding surface: Use a mold to press the sub-conductor so that the welding surface of the corresponding axial sub-conductor group is the same as that of the radial sub-conductor group; S4: Welding: The corresponding axial sub-conductor groups and radial sub-conductor groups are welded one by one using high-frequency welding butt welding process; S5: Cleaning and Insulation: Clean and insulate each group of welded joints to finally complete the connection between the first and second conductors; The insulation described in step S5 is achieved by wrapping with crepe paper. Specifically, this includes wrapping two layers of crepe paper at the welding joint of the axial sub-conductor group and the second sub-conductor, as well as completing the welding and cleaning of each group, and then wrapping four layers of crepe paper at the conductor connection joint after merging the groups.

2. A transformer employing a composite conductor coil according to claim 1, characterized in that, The number of turns in the upper section coil accounts for 5%-6% of the total number of turns in the coil, and the number of turns in the upper section coil is equal to the number of turns in the lower section coil.

3. A method for connecting the first and second conductors in the coil of a transformer employing a composite conductor coil as described in any one of claims 1-2, characterized in that, Includes the following steps: S1: Trimming: Trimming the sub-wires of the first wire to be soldered and trimming the sub-wires of the second wire to be soldered; S2: Wire grouping: Divide the sub-wires in the first wire into several axial sub-wire groups, and divide the sub-wires in the second wire into several radial sub-wire groups. The axial sub-wire groups and radial sub-wire groups correspond one-to-one and are to be welded. S3: Press welding surface: Use a mold to press the sub-conductor so that the welding surface of the corresponding axial sub-conductor group is the same as that of the radial sub-conductor group; S4: Welding: The corresponding axial sub-conductor groups and radial sub-conductor groups are welded one by one using high-frequency welding butt welding process; S5: Cleaning and Insulation: Clean and insulate each weld joint to finally complete the connection between the first and second conductors.

4. The method for connecting the first and second conductors in the coil of a transformer employing a composite conductor coil according to claim 3, characterized in that, The end-trimming correction described in step S1 is performed using a flat-jaw punch pliers.

5. The method for connecting the first and second conductors in the coil of a transformer employing a composite conductor coil according to claim 3, characterized in that, Step S4, the high-frequency welding butt welding, specifically includes the following steps: silver solder pads are placed between the welding surfaces of the axial sub-conductor group and the radial sub-conductor group, and the two are welded together by a high-frequency welding machine.

6. A method for connecting the first and second conductors in the coil of a transformer employing a composite conductor coil according to claim 5, characterized in that, The gap between the axial sub-conductor group and the radial sub-conductor group is 0.2mm-0.5mm.

7. A method for connecting the first and second conductors in the coil of a transformer employing a composite conductor coil according to claim 3, characterized in that, The cleaning described in step S5 refers to removing the oxide layer and sharp corners from the surface of the weld, as well as passivating the edges.

8. A method for connecting the first and second conductors in the coil of a transformer employing a composite conductor coil according to claim 3, characterized in that, The insulation described in step S5 is achieved by wrapping with crepe paper. Specifically, this includes wrapping two layers of crepe paper at the welding joint of the axial sub-conductor group and the second sub-conductor, as well as completing the welding and cleaning of each group, and then wrapping four layers of crepe paper at the conductor connection joint after merging the groups.

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