Magnetic shielding large-current transformer for compensation loop of submerged arc furnace

Abstract

The utility model relates to a large-current transformer for a compensation loop of a submerged arc furnace, in particular to a magnetic shielding large-current transformer for the compensation loop of the submerged arc furnace, and solves the problem that short circuit of a secondary coil between a cross-core conductor and a return conductor is easily caused by the adoption of an existing transformer. The transformer comprises a lower pressing plate, a positioning plate, an upper pressing plate, a lower iron core, an upper iron core, a secondary coil, an insulating baffle plate and a magnetic shielding body, a lower transverse column of the lower iron core is embedded in the lower pressing plate, and two vertical columns of the lower iron core extend out of the lower pressing plate and then are inserted into two first positioning through holes in the positioning plate; a transverse column above the upper iron core is embedded in the upper pressing plate, and two vertical columns of the upper iron core extend out of the upper pressing plate and then are inserted into the two first positioning through holes; the secondary coil is sleeved on a vertical column on the left side of the lower iron core; the two vertical columns of the lower iron core are distributed on the two sides of the insulating baffle. The magnetic shielding body is parallel to the insulating baffle and is positioned on the right side of the lower iron core right vertical column; the lower iron core right side vertical column and the magnetic shielding body are used for being arranged between the cross-core conductor and the return conductor.

Description

Technical Field

[0001] The utility model relates to a large current transformer for a compensation circuit of an ore-fired furnace, in particular to a magnetic shielding large current transformer for the compensation circuit of an ore-fired furnace. Background Art

[0002] Submerged arc furnace is a high energy consumption smelting furnace. Due to the low working voltage and high working current of the submerged arc furnace, a large amount of reactive power is generated due to the circuit inductive reactance during the operation of the submerged arc furnace. In order to improve the working efficiency of the submerged arc furnace and improve the power factor, a reactive power compensation device is usually installed on the short circuit network on the low voltage side of the submerged arc furnace.

[0003] Due to the low working voltage and large compensation capacity, the current of the compensation circuit is relatively large and the voltage is relatively low. The compensation circuit of the submerged arc furnace is generally made of water-cooled copper tubes. Due to the low voltage, the distance between the through-conductor and the return conductor is relatively close, generally between 200mm and 350mm. The current directions of the through-conductor and the return conductor are opposite. Therefore, when using the existing large current transformer for the compensation circuit of the submerged arc furnace, the magnetic field of the secondary coil between the through-conductor and the return conductor is positively superimposed, and its magnetic field strength is much greater than the magnetic field inside the iron core on the other side, which easily causes the secondary coil between the through-conductor and the return conductor to burn out and other insulation failures and short circuit.

[0004] The large current transformer involved in the utility model refers to a transformer whose total current of the through-core conductor to be detected is between 10kA and 30kA. Utility Model Content

[0005] The utility model aims to solve the technical problem that when using the existing large current transformer for the compensation circuit of the electric arc furnace, the secondary coil between the through conductor and the return conductor is easily burned out and short-circuited due to insulation failure, and to provide a magnetically shielded large current transformer for the compensation circuit of the electric arc furnace.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] A magnetically shielded high current transformer for a compensation circuit of an electric arc furnace, which is special in that:

[0008] It includes a lower pressing plate, a positioning plate, an upper pressing plate, a lower iron core, an upper iron core, a secondary coil, an insulating baffle and a magnetic shielding body;

[0009] The lower pressing plate, the positioning plate and the upper pressing plate are arranged horizontally and in parallel from bottom to top, and all three are made of non-magnetic insulating materials;

[0010] The lower iron core and the upper iron core are obtained by cutting a vertically arranged square-shaped rolled iron core into two halves;

[0011] The horizontal column below the lower iron core is embedded in the first groove provided on the upper surface of the lower pressing plate; after the two vertical columns of the lower iron core extend from the upper surface of the lower pressing plate, they are respectively inserted into the two first positioning through holes provided on the positioning plate one by one;

[0012] The horizontal column above the upper iron core is embedded in the second groove provided on the lower surface of the upper pressing plate; after the two vertical columns of the upper iron core extend from the lower surface of the upper pressing plate, they are respectively inserted into the two first positioning through holes one by one, forming a rectangular shape with the lower iron core;

[0013] The secondary coil is sleeved on the left vertical column of the lower iron core and is located between the lower pressing plate and the positioning plate;

[0014] The insulating baffle is arranged between the lower pressing plate and the positioning plate, and its plate surface is perpendicular to the horizontal column below the lower iron core. The two vertical columns of the lower iron core are respectively distributed on both sides of the plate surface of the insulating baffle;

[0015] The plate surface of the magnetic shielding body is parallel to the plate surface of the insulating baffle and is located on the right side of the right vertical column of the lower iron core; the lower end of the magnetic shielding body is inserted into the third groove provided on the upper surface of the lower pressing plate, and after its upper end passes through the second positioning through hole provided on the positioning plate, it is inserted into the fourth groove provided on the lower surface of the upper pressing plate. The upper pressing plate and the lower pressing plate are clamped up and down by the first fastening assembly to realize the connection between the lower pressing plate, the upper pressing plate, the lower iron core, the upper iron core and the magnetic shielding body;

[0016] The right vertical column of the lower iron core and the magnetic shielding body are used to be arranged between the through conductor and the return conductor on the submerged arc furnace reactive power compensation device to realize the connection with the submerged arc furnace compensation circuit.

[0017] Further, in order to have better reliability and higher safety when applied in an environment where a large magnetic field is generated by the return conductor, the cross-sectional area of the magnetic shielding body in the horizontal direction is greater than or equal to four times the cross-sectional area of the rectangular toroidal core.

[0018] Further, the magnetic shielding body is stacked by silicon steel sheets.

[0019] Further, the secondary coil includes a hollow skeleton and an enameled wire wound on the hollow skeleton;

[0020] The hollow skeleton is made of an insulating material; the secondary coil is sleeved on the left vertical column of the lower iron core through the hollow skeleton;

[0021] The total current of the through conductor is between 10 kA and 30 kA.

[0022] Further, for better heat dissipation performance, the enameled wire is wound in multiple layers, with insulating materials provided between layers, and at the positions between multiple layers, a plurality of heat dissipation channels along the vertical direction supported by insulating strips are provided;

[0023] Heat dissipation holes matching the positions and shapes of the heat dissipation channels are provided on the lower pressing plate, the positioning plate, and the upper pressing plate.

[0024] Further, the heat dissipation holes include a plurality of fan-shaped ring holes evenly distributed along the circumferential direction.

[0025] Further, the square coil core is a square coil core wound by silicon steel sheets.

[0026] Further, for convenient connection, the first fastening assembly includes multiple groups of matching first screws and two first nuts.

[0027] Further, the above-mentioned magnetic shielding large current transformer for submerged arc furnace compensation circuit further includes a support;

[0028] The support is fixedly connected below the lower pressing plate.

[0029] Further, for convenient movement, there are two supports, both of which are channel steels;

[0030] The two channel steels are arranged in parallel, and their grooves point outward;

[0031] The two channel steels are both detachably fixedly connected below the lower pressing plate through the second fastening assembly;

[0032] The second fastening assembly includes multiple groups of matching second screws and two second nuts.

[0033] The beneficial effects of the present utility model are:

[0034] (1) In the magnetic shielding large current transformer for the submerged arc furnace compensation circuit of the present utility model, the secondary coil is unevenly arranged, that is, the secondary coil is only sleeved on the left vertical column of the lower iron core, and no secondary coil is provided on the right vertical column of the lower iron core between the through-conductor and the return conductor. In this way, when there are double-sided secondary coils, insulation faults such as burning of the secondary coil between the through-conductor and the return conductor caused by different electromagnetic inductions of the secondary coils can be avoided, and further short-circuit problems can be prevented. At the same time, in the present utility model, a magnetic shielding body is added to the right side of the right vertical column of the lower iron core. By suppressing the interference of the magnetic field generated by the return conductor through the magnetic shielding body, the influence of the magnetic field generated by the return conductor can be greatly reduced, the measurement accuracy of the transformer can be ensured, and the occurrence of short-circuit problems can also be effectively reduced. Therefore, the present utility model solves the technical problem that when using the existing large current transformer for the submerged arc furnace compensation circuit, insulation faults such as burning of the secondary coil between the through-conductor and the return conductor are likely to occur, resulting in short circuits.

[0035] (2) In the magnetic shielding large current transformer for the submerged arc furnace compensation circuit of the present utility model, preferably, the cross-sectional area of the magnetic shielding body in the horizontal direction is greater than or equal to four times the cross-sectional area of the square-shaped wound iron core. In this way, when the magnetic shielding large current transformer for the submerged arc furnace compensation circuit of the present utility model is applied in an environment where the return conductor generates a large magnetic field, it has better reliability and higher safety.

[0036] (3) In the magnetic shielding large current transformer for the submerged arc furnace compensation circuit of the present utility model, preferably, the enameled wire in the secondary coil is wound in multiple layers, and at the positions between multiple layers, a plurality of heat dissipation channels in the vertical direction supported by insulating strips are provided, and heat dissipation holes matching the positions and shapes of the heat dissipation channels are provided on the lower pressing plate, the positioning plate, and the upper pressing plate. Such a setting is beneficial to the circulation of air up and down, has better heat dissipation performance, and can effectively avoid the occurrence of problems such as unstable performance of the transformer caused by overheating. Brief Description of the Drawings

[0037] Figure 1 is a schematic structural diagram of an embodiment of the present utility model.

[0038] The descriptions of the reference numerals in the figure are as follows:

[0039] 1 - upper pressing plate, 2 - positioning plate, 3 - secondary coil, 4 - insulating baffle, 5 - lower pressing plate, 6 - support, 7 - upper iron core, 8 - lower iron core, 9 - magnetic shielding body, 10 - fastening component one, 11 - fastening component two, 12 - through-conductor one, 13 - through-conductor two, 14 - return conductor one, 15 - return conductor two. Detailed Embodiments

[0040] The present utility model will be described in detail below with reference to the drawings and specific embodiments.

[0041] See Figure 1 , for a magnetic shielding large current transformer used in a compensation circuit of a submerged arc furnace of the present utility model, it includes a lower pressing plate 5, a positioning plate 2, an upper pressing plate 1, a lower iron core 8, an upper iron core 7, a secondary coil 3, an insulating baffle 4 and a magnetic shielding body 9.

[0042] The above-mentioned lower pressing plate 5, positioning plate 2 and upper pressing plate 1 are horizontally arranged in parallel from bottom to top in sequence, and all three are made of non-magnetic insulating materials.

[0043] The above-mentioned lower iron core 8 and upper iron core 7 are obtained by cutting a vertically arranged square-shaped wound iron core into upper and lower halves. In this embodiment, the square-shaped wound iron core is a square-shaped wound iron core made of silicon steel sheets. The lower horizontal column of the lower iron core 8 is embedded in the first groove provided on the upper surface of the lower pressing plate 5; after the two vertical columns of the lower iron core 8 extend from the upper surface of the lower pressing plate 5, they are respectively inserted into the two first positioning through holes provided on the above-mentioned positioning plate 2 in one-to-one correspondence; the upper horizontal column of the upper iron core 7 is embedded in the second groove provided on the lower surface of the upper pressing plate 1; after the two vertical columns of the upper iron core 7 extend from the lower surface of the upper pressing plate 1, they are respectively inserted into the two above-mentioned first positioning through holes in one-to-one correspondence, and form a square shape with the lower iron core 8; the lower iron core 8 and the upper iron core 7 are butt-jointed and positioned through the positioning plate 2.

[0044] The above-mentioned secondary coil 3 is sleeved on the left vertical column of the lower iron core 8, and it is located between the lower pressing plate 5 and the positioning plate 2. In this embodiment, the secondary coil 3 includes a hollow skeleton and an enameled wire wound on the hollow skeleton; the hollow skeleton is made of an insulating material; the secondary coil 3 is sleeved on the left vertical column of the lower iron core 8 through the hollow skeleton. Since in the magnetic shielding large current transformer used in the compensation circuit of the submerged arc furnace of this embodiment, the number of turns of the secondary coil 3 is relatively large, therefore, for better heat dissipation performance, in this embodiment, the above-mentioned enameled wire is wound in multiple layers, and an insulating material is provided between layers, and at the positions between multiple layers, a plurality of heat dissipation channels along the vertical direction supported by insulating strips are provided, and heat dissipation holes matching the positions and shapes of the above-mentioned heat dissipation channels are provided on the above-mentioned lower pressing plate 5, positioning plate 2 and upper pressing plate 1, so that it is beneficial to the up and down air circulation and helps to dissipate heat. In this embodiment, the above-mentioned heat dissipation holes include a plurality of fan-shaped holes evenly distributed along the circumferential direction.

[0045] The above-mentioned insulating baffle 4 is arranged between the lower pressing plate 5 and the positioning plate 2, and its plate surface is perpendicular to the lower horizontal column of the lower iron core 8, and the two vertical columns of the lower iron core 8 are respectively distributed on both sides of the plate surface of the insulating baffle 4.

[0046] The plate surface of the above-mentioned magnetic shield 9 is parallel to the plate surface of the above-mentioned insulating baffle 4, and it is located on the right side of the right vertical column of the lower iron core 8; the lower end of the above-mentioned magnetic shield 9 is inserted into the third groove provided on the upper surface of the lower pressing plate 5, and after its upper end passes through the second positioning through hole provided on the positioning plate 2, it is inserted into the fourth groove provided on the lower surface of the upper pressing plate 1. The upper pressing plate 1 and the lower pressing plate 5 are clamped up and down by the first fastening assembly 10 to realize the connection between the lower pressing plate 5, the upper pressing plate 1, the lower iron core 8, the upper iron core 7 and the magnetic shield 9. For the convenience of connection, see Figure 1 , in this embodiment, the first fastening assembly 10 includes multiple groups of matching first screws and two first nuts.

[0047] The right vertical column of the lower iron core 8 and the magnetic shield 9 are used to be arranged between the through-conductor and the return conductor on the submerged arc furnace reactive power compensation device to realize the connection with the submerged arc furnace compensation circuit. The total current of the above-mentioned through-conductor is between 10 kA and 30 kA; in this embodiment, due to the large current, there are two through-conductors and two return conductors respectively, that is Figure 1 the through-conductor one 12 shown in, the through-conductor two 13, the return conductor one 14 and the return conductor two 15. Therefore, correspondingly in this embodiment, the sum of the currents of the through-conductor one 12 and the through-conductor two 13 is between 10 kA and 30 kA. The magnetic shielded large current transformer for the submerged arc furnace compensation circuit in this embodiment uses the through-conductor one 12 and the through-conductor two 13 as the primary coils of the transformer. The through-conductor and the return conductor are generally made of copper tubes, and due to the large current, water cooling is generally required. Since the magnetic field generated by the return conductor is large, therefore, in order to have better reliability and higher safety when applied in an environment where the return conductor generates a large magnetic field, the cross-sectional area of the magnetic shield 9 in the horizontal direction is usually greater than or equal to four times the cross-sectional area of the above-mentioned mouth-shaped wound core, and the greater the current in the through-conductor and the return conductor and the smaller the distance between the through-conductor and the return conductor, the larger the cross-sectional area of the magnetic shield 9 in the horizontal direction. In this embodiment, the magnetic shield 9 is stacked by silicon steel sheets.

[0048] The magnetic shielded large current transformer for the submerged arc furnace compensation circuit in this embodiment preferably further includes a support 6. The above-mentioned support 6 is fixedly connected below the lower pressing plate 5. For the convenience of movement, in this embodiment, there are two of the above-mentioned supports 6, and both are channel steels. The two channel steels are arranged in parallel, and their grooves face outward; both channel steels are detachably fixedly connected below the lower pressing plate 5 through the second fastening assembly 11; in this embodiment, the second fastening assembly 11 includes multiple groups of matching second screws and two second nuts, and the channel steel is provided with mounting holes and fastening holes adapted to the second screws. With such a setting, it is convenient to move with a forklift. The above-mentioned support 6 can also be other section steels or metal material products in addition to the channel steel in this embodiment, and is used for support.

[0049] In summary, in the magnetic shielding large current transformer for the submerged arc furnace compensation circuit of the present utility model, due to the uneven arrangement of the secondary coils and the addition of a magnetic shielding body on the right side of the vertical column on the right side of the lower iron core, therefore, by using the magnetic shielding large current transformer for the submerged arc furnace compensation circuit of the present utility model, it can effectively avoid the occurrence of the problem of the secondary coils between the through-conductor and the return conductor being burned out due to different electromagnetic induction of the secondary coils on both sides, and it has better reliability and higher safety.

Claims

1. A magnetic shielding large current transformer for a submerged arc furnace compensation circuit, characterized in that: It includes a lower pressing plate (5), a positioning plate (2), an upper pressing plate (1), a lower iron core (8), an upper iron core (7), a secondary coil (3), an insulating baffle (4) and a magnetic shielding body (9); The lower pressing plate (5), the positioning plate (2) and the upper pressing plate (1) are arranged horizontally in parallel from bottom to top, and all three are made of non-magnetic insulating materials; The lower iron core (8) and the upper iron core (7) are obtained by cutting a vertically arranged square toroidal core into upper and lower halves; The lower horizontal column of the lower iron core (8) is embedded in the first groove provided on the upper surface of the lower pressing plate (5); after the two vertical columns of the lower iron core (8) extend from the upper surface of the lower pressing plate (5), they are respectively inserted into the two first positioning through holes provided on the positioning plate (2) one by one; The upper horizontal column of the upper iron core (7) is embedded in the second groove provided on the lower surface of the upper pressing plate (1); after the two vertical columns of the upper iron core (7) extend from the lower surface of the upper pressing plate (1), they are respectively inserted into the two first positioning through holes one by one, and form a square shape with the lower iron core (8); The secondary coil (3) is sleeved on the left vertical column of the lower iron core (8), and is located between the lower pressing plate (5) and the positioning plate (2); The insulating baffle (4) is arranged between the lower pressing plate (5) and the positioning plate (2), and its plate surface is perpendicular to the lower horizontal column of the lower iron core (8), and the two vertical columns of the lower iron core (8) are respectively distributed on both sides of the plate surface of the insulating baffle (4); The plate surface of the magnetic shielding body (9) is parallel to the plate surface of the insulating baffle (4), and it is located on the right side of the right vertical column of the lower iron core (8); the lower end of the magnetic shielding body (9) is inserted into the third groove provided on the upper surface of the lower pressing plate (5), and after its upper end passes through the second positioning through hole provided on the positioning plate (2), it is inserted into the fourth groove provided on the lower surface of the upper pressing plate (1), and the upper pressing plate (1) and the lower pressing plate (5) are clamped up and down by a fastening component one (10) to realize the connection between the lower pressing plate (5), the upper pressing plate (1), the lower iron core (8), the upper iron core (7) and the magnetic shielding body (9); The right vertical column of the lower iron core (8) and the magnetic shielding body (9) are used to be arranged between the through conductor and the return conductor on the submerged arc furnace reactive power compensation device to realize the connection with the submerged arc furnace compensation circuit.

2. The large current transformer with magnetic shielding for the compensation circuit of the submerged arc furnace according to claim 1, characterized in that: The cross-sectional area of the magnetic shielding body (9) in the horizontal direction is greater than or equal to four times the cross-sectional area of the square toroidal core.

3. The magnetic shielding large current transformer for the compensation circuit of the submerged arc furnace according to claim 1, characterized in that: The magnetic shielding body (9) is stacked by silicon steel sheets.

4. The magnetic shielding large current transformer for a submerged arc furnace compensation circuit according to claim 1, characterized in that: The secondary coil (3) includes a hollow skeleton and an enameled wire wound on the hollow skeleton; The hollow skeleton is made of an insulating material; the secondary coil (3) is sleeved on the left vertical column of the lower iron core (8) through the hollow skeleton; The total current of the through conductor is between 10 kA and 30 kA.

5. The magnetic shielding large current transformer for a submerged arc furnace compensation circuit according to claim 4, characterized in that: The enameled wire is wound in multiple layers, with insulating materials arranged between layers, and at the positions between multiple layers, a plurality of heat dissipation channels along the vertical direction supported by insulating strips are provided; Heat dissipation holes matching the positions and shapes of the heat dissipation channels are provided on the lower pressing plate (5), the positioning plate (2), and the upper pressing plate (1).

6. The magnetic shielding large current transformer for the compensation circuit of the submerged arc furnace according to claim 5, characterized in that: The heat dissipation holes include a plurality of fan-shaped ring holes evenly distributed along the circumferential direction.

7. The magnetic shielding large current transformer for the compensation circuit of the submerged arc furnace according to claim 1, wherein: The square-shaped wound iron core is a square-shaped wound iron core made of silicon steel sheets.

8. The large current transformer with magnetic shielding for the compensation circuit of the submerged arc furnace according to claim 1, wherein: The first fastening assembly (10) includes multiple groups of matching first screws and two first nuts.

9. The large current magnetic shielding current transformer for the submerged arc furnace compensation circuit according to any one of claims 1 to 8, characterized in that: It further includes a support (6); The support (6) is fixedly connected below the lower pressing plate (5).

10. The large current magnetic shielding current transformer for the submerged arc furnace compensation circuit according to claim 9, characterized in that: There are two supports (6), and both are channel steels; The two channel steels are arranged in parallel, and their channels face outward; The two channel steels are both detachably fixedly connected below the lower pressing plate (5) through a second fastening assembly (11); The second fastening assembly (11) includes multiple groups of matching second screws and two second nuts.

Images