Electromagnetic shielding device with annular structure

Abstract

The beneficial effect of the invention is that the provided electromagnetic shielding device with the annular structure is provided. According to the electromagnetic shielding device of the annular structure composed of the low-resistance conductor, the insulating layer, the grounding wire and the grounding fastener, circulating current can be generated through the shielding ring, and then reverse magnetic flux is generated by the circulating current to counteract leakage magnetic flux, so that the shielding effect is achieved. Through the reliable grounding of the grounding lead, the grounding fastener, the oil tank, the clamp and the like, the discharge fault caused by potential suspension can be avoided. The electromagnetic shielding device of the annular structure is good in shielding and loss reduction effect, simple in process, low in application cost and beneficial to cost reduction and efficiency improvement of enterprises.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformer design and manufacturing, and more specifically, it is an annular electromagnetic shielding device. Background Art

[0002] A power transformer is a device that uses the principle of electromagnetic induction to change the voltage of a power system. With the increase in social power consumption and the implementation of higher-level energy efficiency standards by the national power grid, the demand for large-capacity, high-impedance, and low-loss transformers is increasing. Along with the increase in the capacity and impedance of the transformer, the current and leakage magnetic flux of the transformer also increase. When the transformer is operating, a magnetic field will be generated after the winding passes through the current. Since the iron core of the transformer is made of cold-rolled grain-oriented silicon steel sheets, which have excellent magnetic conductivity, most of the magnetic flux circulates in the iron core. However, a part of the magnetic flux also enters metal structural parts such as the transformer tank, pull plate, and clamping parts through air gaps or transformer oil, thereby inducing eddy currents on these structural parts and increasing the stray losses of the transformer. With the increase in current and leakage magnetic flux, the losses generated on the metal structural parts are greater, and even cause local overheating of the metal structural parts, and then cause the cracking of the transformer oil to generate a large amount of harmful gases, seriously endangering the safe operation of the transformer.

[0003] In order to reduce the stray losses generated by the leakage magnetic flux of the transformer on the metal structural parts and avoid local overheating, currently, the industry usually adopts the method of installing electrical and magnetic shields. Specifically, there are the following two conventional methods: ① Install magnetic shields on metal structural parts such as the tank wall and clamping parts. The leakage magnetic flux enters the magnetic shield instead of directly entering the metal structural parts where the magnetic shield is located. Since the cold-rolled grain-oriented silicon steel sheet used for the magnetic shield has much better magnetic conductivity than the metal structural parts, the generated losses are very small and no local overheating phenomenon will occur. ② Install copper shields (electrical shields) at large-area flat structural parts such as the tank wall and the wall of the elevated seat. The copper shield generally uses 6mm-T2 pure copper plates and is fixed on the surface of the shielded structural parts by welding. After the leakage magnetic flux enters the copper shield, because copper is a diamagnetic material, eddy currents will be induced on its surface, and the magnetic field generated by the eddy currents is opposite to the incident magnetic flux, thus generating a cancellation effect, so that the leakage magnetic flux cannot pass through the copper shield and enter the structural parts behind it, achieving the shielding effect.

[0004] However, the above conventional methods have many problems. Taking the magnetic shield as an example, the plate-shaped and L-shaped magnetic shields are generally located far from the coil end, and due to the limited coverage range, the shielding and loss reduction effects are not very ideal. For the new lobe magnetic shield, although the shielding and loss reduction effects are better, its process is complex and the application cost is very high, which runs counter to the goal of cost reduction and efficiency improvement of enterprises. And simply setting the copper shield, the effect itself is not ideal, and due to problems such as cost and welding process, it is not the preferred solution for transformer manufacturers.

[0005] Developing a new shielding device requires not only good shielding effect, but also simple structure, convenient installation and low cost, which is the key technology in the design of transformers at home and abroad. Summary of the Invention

[0006] The present invention provides an electromagnetic shielding device with a ring structure to solve the above-mentioned technical problems, and the following technical solutions are specifically adopted:

[0007] An electromagnetic shielding device with a ring structure includes: a ring shielding structure, a transformer oil tank, clamping parts, pull plates; arc-shaped plates; coil pressing plates. The ring shielding structure is composed of a low-resistance conductor, a grounding wire and a grounding fastener; the low-resistance conductor is a ring with its head and tail connected; the low-resistance conductor is connected to the grounding wire; the grounding wire is connected to the grounding fastener; the grounding wire and the grounding fastener form a ground connection; the grounding fastener is connected to the transformer oil tank, clamping parts, and pull plates.

[0008] A further solution is that the low-resistance conductor is a rectangular ring or a circular ring; an insulating layer is wrapped around the outer layer of the low-resistance conductor.

[0009] A further solution is that a first ring shielding structure is installed on the side of the transformer oil tank; a fixed bracket is provided on the side of the transformer oil tank; the first ring shielding structure is fixed on the wall of the transformer oil tank through the fixed bracket; the first ring shielding structure is arranged in 2 groups up and down; the 2 groups of the first ring shielding structure are concentrically arranged by 4 low-resistance conductors; each of the 2 groups of the first ring shielding structure has 1 grounding point.

[0010] A further solution is that each low-resistance conductor of the first ring shielding structure is a rectangular ring; each low-resistance conductor of the first ring shielding structure is connected by a grounding wire.

[0011] A further solution is that a second ring shielding structure is installed on the side of the transformer oil tank near the high-voltage outgoing line through-hole; the second ring shielding structure is arranged in 2 groups up and down; the 2 groups of the second ring shielding structure are arranged in a matrix; the 2 groups of the second ring shielding structure both use 8 low-resistance conductors; each of the 2 groups of the second ring shielding structure has 4 grounding points; the grounding points of the 2 groups of the second ring shielding structure are longitudinally arranged between 2 low-resistance conductors.

[0012] A further solution is that each low-resistance conductor of the second ring shielding structure is a rectangular ring; each low-resistance conductor of the second ring shielding structure is horizontally connected by a grounding wire.

[0013] A further solution is that a third ring shielding structure is arranged on the outer periphery of the coil pressing plate; a fourth ring shielding structure is arranged on the surfaces of the clamping parts and pull plates.

[0014] A further solution is that the fourth annular shielding structure of the clamping parts and the tie plates consists of two sets of concentrically arranged low-resistance conductors; the low-resistance conductors are rectangular rings; each annular shielding structure of the third annular shielding structure and the fourth annular shielding structure is grounded.

[0015] A further solution is that a fifth annular shielding structure is embedded in the coil pressing plate; a sixth shielding structure is arranged on the surfaces of the clamping parts and the tie plates.

[0016] A further solution is that the sixth annular shielding structure consists of concentrically arranged low-resistance conductors; the low-resistance conductors are rectangular rings; the fifth annular shielding structure and the sixth annular shielding structure are grounded.

[0017] The positive effects of the present invention: It can effectively isolate the internal circuit from external interference sources, optimize the electromagnetic field distribution, reduce the influence of electromagnetic radiation on the circuit, and improve the stability and reliability of the system. By using the annular electromagnetic shielding device composed of low-resistance conductors, insulating layers, grounding wires and grounding fasteners, the present invention can generate circulating current through the shielding ring, and the circulating current then generates reverse magnetic flux to cancel the leakage magnetic flux, thereby achieving the shielding effect. Through the reliable grounding of the grounding wires, grounding fasteners and the oil tank, clamping parts, etc., it can avoid discharge faults caused by potential suspension. The annular electromagnetic shielding device has good shielding and loss reduction effects, simple process, effectively reduces the material cost of the transformer, and is beneficial for enterprises to reduce costs and increase efficiency. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a plan view of an annular electromagnetic shielding device involved in the present application;

[0020] Figure 2 It is a plan view and a sectional view of the annular electromagnetic shielding device installed inside the transformer oil tank;

[0021] Figure 3 It is a plan view and a sectional view of the annular electromagnetic shielding device installed at the high-voltage outgoing line through part inside the transformer oil tank;

[0022] Figure 4 and Figure 5 It is a plan view and an elevation view of the annular electromagnetic shielding device installed on the coil pressing plate, clamping parts and tie plates.

[0023] Ring-shaped shielding structure 100, low-resistance conductor 101, insulating layer 102, grounding wire 103, grounding fastener 104, transformer tank 201, first ring-shaped shielding structure 202, fixing bracket 203, grounding 204, second ring-shaped shielding structure 302, fixing bracket 303, third ring-shaped shielding structure 400, clamping piece 401, coil pressing plate 403, third ring-shaped shielding structure 404, fourth ring-shaped shielding structure 405, pull plate 407, fifth ring-shaped shielding structure 504, sixth ring-shaped shielding structure 505 Detailed implementation mode

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and the detailed implementation mode.

[0025] As Figure 1 shown, it is an electromagnetic shielding device with a ring-shaped structure, including: ring-shaped shielding structure 100, transformer tank 201, clamping piece 401, pull plate 407, coil pressing plate 403. The ring-shaped shielding structure 100 is composed of a low-resistance conductor 101, a grounding wire 103 and a grounding fastener 104. The low-resistance conductor 101 is a ring with its head and tail connected. The low-resistance conductor 101 is connected to the grounding wire 103, and the grounding wire 103 is connected to the grounding fastener 104. The grounding wire 103 and the grounding fastener 104 form a grounding 204, and the grounding fastener 104 is connected to the transformer tank 201, the clamping piece 401 and the pull plate 407. The low-resistance conductor 101 is a rectangular ring or a circular ring wrapped with an insulating layer 102. The material of the low-resistance conductor 101 includes but is not limited to copper stranded wire, copper rod, copper busbar, aluminum rod, aluminum plate, etc. The material and cross-section are determined according to the magnitude of the circulating current in the ring. The low-resistance conductor 101 is reliably grounded to the transformer tank 201, the clamping piece 401, etc. through the grounding 204 to avoid discharge faults caused by potential suspension.

[0026] As Figure 2 shown, the side tank wall of the transformer tank 201 installs the first ring-shaped shielding structure 202 through a fixing bracket 203. The first ring-shaped shielding structure 202 is arranged in two groups up and down. The two groups of the first ring-shaped shielding structures 202 are concentrically arranged by 4 low-resistance conductors 101. Each of the two groups of the first ring-shaped shielding structures 202 is provided with one grounding 204. Each low-resistance conductor 101 of the first ring-shaped shielding structure 202 is a rectangular ring connected by a grounding wire. The best shielding effect can be achieved through the two groups up and down and the concentric arrangement. The first ring-shaped shielding structure 202 is fixed on the transformer tank wall through the fixing bracket 203 and maintains an appropriate distance to reduce the influence of the circulating current in the ring on the transformer tank wall. One grounding 204 is provided for each group of the ring-shaped shielding structures 100 to directly obtain a reliable potential on the inner wall of the transformer tank.

[0027] As Figure 3As shown, a second annular shielding structure 302 is installed on one side of the transformer oil tank 201 close to the high-voltage line through-hole. The second annular shielding structure 302 is arranged in two upper and lower rectangular arrays. The two groups of second annular shielding structures 302 use 8 low-resistance conductors 101. The two groups of second annular shielding structures 302 are each provided with 4 grounding points, and each group of grounding is longitudinally arranged between two low-resistance conductors 101. Figure 3 and Figure 2 The difference is that each group of annular shielding structures 100 is arranged in a rectangular array, which is more suitable for scenarios where concentric arrangement is difficult. The fixed bracket 303 is arranged according to the rectangular array and adjusted to a long strip of low-resistance conductors 101 in series, which is easy to install and disassemble.

[0028] like Figure 4 As shown, each low resistance conductor 101 of the second annular shielding structure 302 is a rectangular ring, and each low resistance conductor 101 is horizontally connected by a grounding wire 103. The third annular shielding structure 404 is arranged on the periphery of the coil pressing plate 403, and the fourth annular shielding structure 405 is arranged on the surface of the clamp 401 and the pull plate 407. The fourth annular shielding structure 405 of the clamp 401 and the pull plate 407 is two groups of concentrically arranged low resistance conductors 101, the low resistance conductors 101 are rectangular rings, and each group of annular shielding structures 100 of the third annular shielding structure 404 and the fourth annular shielding structure 405 is provided with a ground 204.

[0029] like Figure 5 As shown, Figure 5 Another arrangement method of another annular shielding structure 100 on the coil pressing plate 403, the clamp 401 and the pull plate 407 is shown. The coil pressing plate 403 is embedded with a fifth annular shielding structure 504, and the clamp 401 and the pull plate 407 are arranged with a sixth shielding structure 505. The sixth annular shielding structure 505 is a concentrically arranged low-resistance conductor 101, which is a rectangular ring. The fifth annular shielding structure 504 and the sixth annular shielding structure 505 are provided with a grounding 204.

[0030] When the coil leakage flux enters the coil pressure plate 403, the clamp 401 and the pull plate 407, the low resistance conductor 101 generates a circulating current, which in turn generates a reverse magnetic flux to offset the leakage magnetic flux, thereby achieving a shielding effect.

[0031] The above embodiments are descriptions of specific implementation methods of the present invention rather than limitations of the present invention. Technical personnel in the relevant technical field can make various changes and modifications to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should be included in the patent protection scope of the present invention.

Claims

1. An electromagnetic shielding device with a ring structure, characterized in that Comprising: An annular shielding structure, a transformer oil tank, clamping parts, a pull plate, and a coil pressing plate; The annular shielding structure is composed of a low-resistance conductor, a grounding wire, and a grounding fastener; The low-resistance conductor is an annular shape with its head and tail connected; The low-resistance conductor is connected to the grounding wire; The grounding wire is connected to the grounding fastener; The grounding wire and the grounding fastener form a ground connection; The grounding fastener is connected to the transformer oil tank, the clamping parts, and the pull plate.

2. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that The low-resistance conductor is a rectangular ring or a circular ring; An insulating layer is wrapped around the outer layer of the low-resistance conductor.

3. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that A first annular shielding structure is installed on the side of the transformer oil tank; A fixed bracket is provided on the side of the transformer oil tank; The first annular shielding structure is fixed on the wall of the transformer oil tank through the fixed bracket; The first annular shielding structure is arranged in 2 groups up and down; The 2 groups of the first annular shielding structures are concentrically arranged by 4 low-resistance conductors; Each of the 2 groups of the first annular shielding structures is provided with 1 grounding point.

4. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that Each low-resistance conductor of the first annular shielding structure is a rectangular ring; Each low-resistance conductor of the first annular shielding structure is connected by a grounding wire.

5. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that A second annular shielding structure is installed on one side of the transformer oil tank close to the high-voltage outgoing line through-hole; The second annular shielding structure is arranged in 2 groups up and down; The 2 groups of the second annular shielding structures are arranged in a matrix pattern; Each of the 2 groups of the second annular shielding structures uses 8 low-resistance conductors; Each of the 2 groups of the second annular shielding structures is provided with 4 grounding points; The grounding of the 2 groups of the second annular shielding structures is longitudinally arranged between 2 low-resistance conductors.

6. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that Each low-resistance conductor of the second annular shielding structure is a rectangular ring; Each low-resistance conductor of the second annular shielding structure is horizontally connected by a grounding wire.

7. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that A third annular shielding structure is arranged on the outer periphery of the coil pressing plate; A fourth annular shielding structure is arranged on the surfaces of the clamping parts and the pull plate.

8. The electromagnetic shielding device with an annular structure according to claim 7, characterized in that The fourth annular shielding structure of the clamping parts and the pull plate is 2 groups of concentrically arranged low-resistance conductors; the low-resistance conductor is a rectangular ring; Each group of the annular shielding structures of the third annular shielding structure and the fourth annular shielding structure is provided with a grounding point.

9. The electromagnetic shielding device with an annular structure according to claim 1, characterized in that A fifth annular shielding structure is embedded in the coil pressing plate; A sixth shielding structure is arranged on the surfaces of the clamping parts and the pull plate.

10. The electromagnetic shielding device with an annular structure according to claim 9, characterized in that The sixth annular shielding structure is concentrically arranged low-resistance conductors; The low-resistance conductor is a rectangular ring; The fifth annular shielding structure and the sixth annular shielding structure are grounded.

Images