Current transformer special for gas insulated switchgear

Abstract

According to the technical scheme, the current transformer special for the gas insulated switchgear is characterized by comprising a medium body, a primary winding and a secondary winding, the primary winding and the secondary winding are arranged in the medium body, the primary winding penetrates through and is wound around the secondary winding, and the secondary winding comprises a measuring winding and a protection winding; a V-shaped bracket is arranged in the medium body and is arranged on the right side of the medium body; the bottom surface of the medium body is provided with a sealing groove used for installing a sealing ring. A coil of the current primary winding is a multi-turn coil. Under the action of the V-shaped support, the position of the internal coil in the transformer is fixed in the pouring process, so that inner hole pouring layers of the primary winding and the secondary winding are uniform, the measurement precision of the transformer is guaranteed, and the secondary winding obtains higher measurement precision due to the fact that the primary winding adopts the multi-turn coil.

Description

Technical Field

[0001] The utility model relates to the technical field of current transformers, and more specifically to a current transformer dedicated to an inflatable cabinet. Background Art

[0002] A gas transformer is a type of switchgear used in the electrical industry. It is filled with a protective gas, such as sulfur hexafluoride (SF6). High-voltage components within the transformer are sealed in a housing filled with lower-pressure SF6 gas. To ensure the insulation and safety of the transformer, it is necessary to prevent the SF6 gas from leaking. Current transformers operate based on the principle of electromagnetic induction and are typically constructed with a closed iron magnetic conductor and windings. They are typically used to measure large currents or protect circuits. They can also provide isolation protection.

[0003] At present, the Chinese patent with announcement number CN201920747775.3 discloses a current transformer dedicated to an inflatable cabinet, including a primary current coil, a primary equipotential terminal, a secondary current coil, a secondary terminal, an insulating medium and two sets of primary terminals; the two sets of primary terminals are respectively connected to the two ends of the primary current coil; the primary current coil passes through the secondary current coil; the secondary current coil is connected to the secondary terminals; the primary equipotential terminal is respectively connected to the two sets of primary terminals; the primary terminal, the primary current coil, the primary equipotential terminal, the secondary current coil and the secondary terminal are cast into one through the insulating medium.

[0004] However, the above-mentioned existing technology still has some defects: due to the increase in the number of turns of the coil, the use range of this current transformer will be smaller than that of other current transformers, and it is easy to burn out when the current fluctuates greatly; the transformer needs to be rotated 90 degrees when cast. Due to the special nature of casting, the position of the internal coil inside the transformer will change during the production casting process, resulting in uneven casting layers at both ends of the primary and secondary windings and their inner holes, which affects the field strength and reduces the partial discharge level of the product. Utility Model Content

[0005] In view of the deficiencies in the prior art, the present invention provides a current transformer dedicated to an inflatable cabinet, which has higher accuracy and sealing performance.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: comprising a dielectric body, a primary winding and a secondary winding, wherein the primary winding and the secondary winding are arranged in the dielectric body, the primary winding passes through and is wound around the secondary winding, and the secondary winding includes a measuring winding and a protective winding; a V-shaped bracket is provided in the dielectric body, and the V-shaped bracket is provided on the right side of the dielectric body; a sealing groove for installing a sealing ring is provided on the bottom surface of the dielectric body, and a shielding sealing plate is provided on the bottom surface of the dielectric body.

[0007] The utility model is further configured as follows: the inner side of the V-shaped bracket is close to the outer edge of the primary winding, the upper surface of the V-shape is close to the secondary winding, and the upper surface of the V-shaped bracket has a protrusion A and a protrusion B, the protrusion A is located at the lower side of the bending of the V-shaped bracket, and the upper left end of the protrusion B is close to the secondary winding.

[0008] The utility model is further configured as follows: the dielectric body is epoxy resin.

[0009] The present invention is further configured such that: the coil of the primary winding is a multi-turn coil.

[0010] The utility model is further configured as follows: the dielectric body is sprayed with conductive paint.

[0011] The utility model is further configured as follows: the material of the shielding sealing plate is aluminum.

[0012] In summary, the utility model has the following beneficial effects: the V-shaped bracket provides support for the secondary winding and controls the relative position of the secondary winding and the primary winding, so that the position of the internal coil inside the transformer is fixed during the casting process, so that the casting layer of the inner hole of the primary and secondary windings is uniform, thereby ensuring the measurement accuracy of the utility model; the primary winding adopts a multi-turn coil so that the secondary winding obtains higher measurement accuracy; the sealing ring and the isolation sealing plate arranged on the bottom surface ensure that the connection between the current transformer and the gas cabinet is reliably sealed to avoid the occurrence of air leakage; the shielding sealing plate ensures that the gas cabinet is reliably sealed during operation while reducing interference from the external magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural diagram of this embodiment;

[0014] Figure 2 This is a top view of the V-shaped bracket of this embodiment;

[0015] Figure 3 This is a cross-sectional view taken along the line A of this embodiment;

[0016] Figure numerals: 1. dielectric body; 2. primary winding; 3. secondary winding; 31. measuring winding; 32. protection winding; 4. V-shaped bracket; 41. protrusion A; 42. protrusion B; 5. shielding sealing plate; 51. sealing ring. DETAILED DESCRIPTION

[0017] The present invention will be described in further detail below with reference to the accompanying drawings.

[0018] This embodiment discloses a current transformer dedicated to an inflatable cabinet, such as Figure 1As shown, it includes a dielectric body 1, a primary winding 2 and a secondary winding 3, the primary winding 2 and the secondary winding 3 are arranged in the dielectric body 1, the primary winding 2 is fastened to the mold by bolts, the primary winding 2 passes through and is wound around the secondary winding 3, and the secondary winding 3 includes a measuring winding 31 and a protective winding 32; the internal gap of the dielectric body 1 is cast by insulating material, including casting insulating material between the primary winding 2 for high voltage passing and the measuring winding 31 for measuring low voltage and the protective winding 32 for protecting the measuring winding 31 for insulation isolation; a V-shaped bracket 4 is provided in the dielectric body 1, the V-shaped bracket 4 is arranged on the right side of the dielectric body 1, and the secondary winding 3 is supported in the mold cavity by the V-shaped bracket 4; a sealing groove for installing a sealing ring 51 is provided on the bottom surface of the dielectric body 1, and a shielding sealing plate 5 is provided on the bottom surface of the dielectric body 1. The shielding sealing plate 5 is made of aluminum, which is a commonly used metal material with good electrical conductivity and electromagnetic shielding performance, and is cheap and lightweight. By providing a sealing ring 51 and a shielding sealing plate 5 on the bottom surface, the connection between the current transformer and the gas cabinet is reliably sealed to avoid leakage; the shielding sealing plate 5 ensures that the gas cabinet is reliably sealed during operation while reducing interference from the external magnetic field.

[0019] For further improvement, the transformer needs to be rotated 90 degrees when cast. Due to the particularity of casting, the position of the internal coil in the transformer will change during the production casting process. A protection winding for protection is set in the secondary winding, which improves the quality of the secondary winding, making the positioning and fixing errors of the windings between the windings more severe, which is unreliable, increases the error of the current transformer, and reduces the accuracy of the transformer; a V-shaped bracket is used for positioning and auxiliary support, and the inner side of the V-shaped bracket 4 is close to the outer edge of the primary winding 2. The relative position of the V-shaped bracket 4 is determined by the position of the primary winding 2. The upper surface of the V-shaped bracket 4 is close to the secondary winding 3, and the distance from the upper surface of the V-shaped bracket 4 to the bottom surface is used to position the secondary bracket, such as Figures 2 to 3 As shown, the upper surface of the V-shaped bracket 4 has a protrusion A41 and a protrusion B42. The protrusion A41 is located at the lower side of the bend of the V-shaped bracket 4, and the upper left end of the protrusion B42 is close to the secondary winding 3. The side edges of the protrusions A41 and B42 cooperate with the second winding to determine the position of the secondary winding 3 in two different directions. At this point, the position of the second winding relative to the first winding can be controlled.

[0020] Further improvement is that the coil of the primary winding 2 is a multi-turn coil. The primary and secondary ampere-turns are increased, and the magnetic induction intensity of the iron core inside the secondary winding 3 is increased without increasing the volume of the secondary winding 3, so that the current transformer achieves higher measurement accuracy and higher protection multiples.

[0021] Furthermore, the dielectric body 1 is made of epoxy resin. Since the dielectric body 1 is cast and the secondary winding 3 needs to be stably supported in the mold cavity by the V-shaped bracket 4, the V-shaped bracket 4 should be made of the same material as the dielectric body 1, that is, epoxy resin. Therefore, the V-shaped bracket 4 is made of a cured epoxy resin mixed adhesive.

[0022] Further improvement, the dielectric body 1 is sprayed with conductive paint, which is a paint containing conductive particles. By spraying or brushing, the non-metallic or non-conductive surface has the same electromagnetic wave absorption, conduction and attenuation characteristics as metal, forming a shielding layer. The shielding layer can prevent the new device from being affected by electromagnetic interference from the external environment and reduce measurement errors.

[0023] Working principle of the utility model

[0024] The primary winding 2 is connected to the power supply, and current flows through the primary winding 2, generating alternating magnetic flux in the iron core of the primary winding 2 and the iron core of the protection coil. According to the principle of electromagnetic induction, the alternating magnetic flux generates induced current output signals in the measurement-level low-voltage secondary coil and the protection-level low-voltage secondary coil respectively. The signal is supplied to the instrument equipment from the secondary signal output end to the secondary circuit connected to the inflatable cabinet.

[0025] The current transformer is placed in an insulating dielectric body 1 cast with epoxy resin. The internal gap of the dielectric body 1 is formed by casting epoxy resin material, and epoxy resin is cast between the primary winding 2 and the secondary winding 3 to form an insulation isolation system. When the primary current is small, the primary winding 2 can be made into a multi-turn coil to increase the primary and secondary ampere-turns and improve the magnetic induction intensity of the iron core inside the secondary winding 3. Due to the presence of the protection coil, the current transformer can be protected when the current is relatively large or surges, obtaining a stable and good working state, so that the current transformer can achieve higher measurement accuracy and higher protection multiples.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the design concept of the present invention should be included in the scope of protection of the present invention.

Claims

1. A current transformer for an inflatable cabinet, comprising a dielectric body (1), a primary winding (2) and a secondary winding (3), wherein the primary winding (2) and the secondary winding (3) are arranged in the dielectric body (1), and characterized in that: The primary winding (2) passes through and is wound around the secondary winding (3), the primary winding (2) is located in the center, and the secondary winding (3) includes a measuring winding (31) and a protection winding (32); a V-shaped bracket (4) is provided in the dielectric body (1), and the V-shaped bracket (4) is arranged on the right side of the dielectric body (1); a sealing groove for installing a sealing ring (51) is provided on the bottom surface of the dielectric body (1), and a shielding sealing plate (5) is provided on the bottom surface of the dielectric body (1).

2. The current transformer for an inflatable cabinet according to claim 1, characterized in that: The inner side of the V-shaped bracket (4) is close to the outer edge of the primary winding (2), and the upper surface of the V-shaped bracket (4) is close to the secondary winding (3). The upper surface of the V-shaped bracket (4) has a protrusion A (41) and a protrusion B (42), wherein the protrusion A (41) is located at the lower side of the bending of the V-shaped bracket (4), and the upper left end of the protrusion B (42) is close to the secondary winding (3).

3. The current transformer for an inflatable cabinet according to claim 1, characterized in that: The dielectric body (1) is epoxy resin.

4. The current transformer for an inflatable cabinet according to claim 1, characterized in that: The coil of the primary winding (2) is a multi-turn coil.

5. The current transformer for an inflatable cabinet according to claim 1, characterized in that: The dielectric body (1) is sprayed with conductive paint.

6. The current transformer dedicated to an inflatable cabinet according to claim 1, characterized in that: The shielding sealing plate (5) is made of aluminum.

Images