Zero flux current transformer

Abstract

This utility model relates to the field of electrical engineering technology and discloses a zero-flux current transformer, including a housing, an insulating bushing, a base, and a transformer body. The transformer body is vertically mounted inside the housing, and a primary conductor is installed inside to carry high-voltage direct current. A zero-flux coil is installed at the upper end of the transformer body to sense the magnetic field generated by the current in the primary conductor and output a secondary current. The zero-flux coil is located inside a shield and grounded to improve measurement accuracy and stability. The transformer is filled with SF6 gas for electrical insulation, and a silicone rubber coating is provided on the outside of the zero-flux coil as a buffer layer to protect the coil from the influence of internal gas pressure. The transformer body is connected in series in a DC circuit system through the primary conductor, and the secondary current is introduced into the zero-flux electronic module via a cable to output a secondary signal. This utility model improves the measurement accuracy and stability of the current transformer, enhances safety and reliability, and is suitable for high-voltage direct current environments.

Description

Technical Field

[0001] This utility model relates to the field of electrical engineering technology, specifically to a zero-flux current transformer. Background Technology

[0002] In the high-voltage electrical industry, zero-flux current transformers are important electrical components, widely used for current measurement in DC power systems. Traditional zero-flux current transformers typically employ a horizontal mounting structure using a wall bushing as the carrier. This design comprises two main parts: the wall bushing, which provides primary electrical insulation, and the low-voltage coil used for current measurement. However, with the increasing prevalence of compact substations, the traditional horizontally mounted zero-flux current transformer, due to its large footprint, is gradually revealing more and more application limitations.

[0003] In traditional zero-flux current transformer designs, high-voltage direct current flows through the central conductor of the bushing, while the zero-flux coil is mounted outside the bushing and connected to ground potential. In this design, the zero-flux coil induces a secondary current, which is then introduced into the zero-flux electronic module via a cable, thereby outputting an ideal secondary signal. The bushing primarily provides electrical insulation between the primary high-voltage coil and the zero-flux coil. However, given the stringent space requirements of compact substations, traditional designs are no longer sufficient to meet market demands. Utility Model Content

[0004] The purpose of this invention is to provide a zero-flux current transformer, which carries high-voltage direct current through a primary conductor, induces a magnetic field in a zero-flux coil and outputs a secondary current, and outputs a secondary signal after processing by a zero-flux electronic module. At the same time, it uses SF6 gas for electrical insulation and improves measurement accuracy, stability and safety through a series of designs.

[0005] To solve the above-mentioned technical problems, this utility model provides a zero-flux current transformer, comprising:

[0006] The housing, the insulating sleeve, and the base, wherein the upper part of the insulating sleeve is connected to the housing and communicates with the interior of the housing.

[0007] The current transformer body is vertically mounted and disposed inside the housing.

[0008] The primary conductor, located inside the transformer body, is used to carry high-voltage direct current.

[0009] The zero flux coil is installed inside the transformer body and located at the upper end of the transformer body. The zero flux coil is used to sense the magnetic field generated by the high voltage direct current flowing through the primary conductor and output the secondary current.

[0010] In addition to the above-mentioned technical features, this application also makes improvements in the following aspects:

[0011] In some embodiments, the zero flux coil is located inside a shielding cover disposed within the transformer body, and the shielding cover is grounded, thereby placing the zero flux coil at ground potential.

[0012] In some embodiments, the transformer is filled with SF6 gas, and the zero flux coil is in an SF6 gas insulating environment, wherein the SF6 gas is used to provide electrical insulation between the primary conductor and the zero flux coil.

[0013] In some embodiments, a buffer layer is provided outside the zero flux coil, the buffer layer being used to buffer the gas pressure generated by the SF6 gas filled inside the transformer body on the zero flux coil.

[0014] In some embodiments, the buffer layer is a silicone rubber coating cast onto the outside of the zero flux coil.

[0015] In some embodiments, the transformer body is connected in series in a DC circuit system via a primary conductor. When a high-voltage DC current flows through the primary conductor, the zero-flux coil induces the current and outputs a secondary current. The secondary current is introduced into the zero-flux electronic module through a cable to output a secondary signal.

[0016] In some embodiments, a rupture disc is installed on the upper part of the housing to release SF6 gas, thereby protecting the housing and the insulating sleeve.

[0017] In some embodiments, the insulating sleeve is a composite insulating sleeve, and the outer surface of the composite insulating sleeve is cast with glass fiber of silicone rubber umbrella skirt.

[0018] In some embodiments, a density relay is provided on the base for detecting changes in SF6 gas density.

[0019] In some embodiments, the base is further provided with a secondary terminal box for connecting and transmitting the secondary signals output by the zero flux electronic module.

[0020] By adopting the above technical solution, this utility model has at least one of the following beneficial effects:

[0021] 1. High-precision measurement: By inducing the magnetic field generated by the high-voltage direct current in a primary conductor through a zero-flux coil and outputting a secondary current, high-precision measurement of direct current is achieved. Zero-flux technology can effectively compensate for errors in the measurement process, improving the accuracy and stability of the measurement.

[0022] Meanwhile, the zero flux coil is located inside the shielding cover of the transformer body. The grounding of the shielding cover keeps the zero flux coil at ground potential, effectively preventing electrical interference and noise from affecting the zero flux coil, and further improving the measurement accuracy and stability of the transformer.

[0023] 2. Excellent electrical insulation performance: The transformer is filled with SF6 gas, which has excellent electrical insulation properties and can withstand high voltage without breakdown, thus ensuring reliable operation of the transformer in high-voltage environments. The zero-flux coil is surrounded by SF6 gas insulation, further enhancing its electrical insulation performance.

[0024] 3. Compact and reliable structure: The instrument transformer body is vertically mounted inside the housing, resulting in a compact structure and saving space. Furthermore, a rupture disc is installed at the top of the housing. When the internal pressure becomes too high, the rupture disc releases SF6 gas, thereby protecting the housing and insulating bushings from damage and improving the safety of the instrument transformer.

[0025] 4. Enhanced mechanical protection: A silicone rubber coating is installed on the outside of the zero flux coil as a buffer layer, which effectively buffers the gas pressure generated by SF6 gas on the zero flux coil, protects the zero flux coil from the influence of internal gas pressure, and enhances the mechanical reliability of the transformer.

[0026] 5. Easy to install and maintain: The density relay on the base can monitor the density change of SF6 gas in real time. When the density drops to a certain level, it will issue an alarm signal to remind maintenance personnel to replenish SF6 gas in time, ensuring the normal operation of the instrument transformer.

[0027] Meanwhile, a secondary terminal box is also provided on the base for connecting and transmitting the secondary signals output by the zero flux electronic module, making the wiring and signal transmission of the current transformer more convenient.

[0028] 6. High adaptability: The insulating sleeve adopts a composite insulating sleeve with glass fiber with silicone rubber umbrella skirt cast on the outer surface, which has good weather resistance and anti-pollution flashover ability, and is suitable for various harsh environments.

[0029] In summary, this zero-flux current transformer, through its unique design and structure, improves measurement accuracy and stability, enhances safety and reliability, facilitates maintenance and management, adapts to high-voltage DC current environments, and optimizes signal transmission and processing, making it a high-performance current transformer. Attached Figure Description

[0030] The accompanying drawings, which are provided to further illustrate the present invention and constitute a part of the present invention, illustrate exemplary embodiments of the present invention and are used to explain the present invention, but do not constitute an undue limitation of the present invention.

[0031] Figure 1 A schematic diagram of an existing SF6 gas-insulated zero-flux current transformer.

[0032] Figure 2 This is a schematic diagram of the overall structure of the zero-flux current transformer of this utility model.

[0033] The numbers in the diagram are as follows:

[0034] 1. Rupture disc; 2. Housing; 3. Primary conductor; 4. Zero flux coil; 5. Shielding cover; 6. Insulating sleeve; 7. Secondary terminal box; 8. Relay; 9. SF6 gas. Detailed Implementation

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present invention or its application or use. The present invention may be implemented in other different forms and is not limited to the embodiments described herein.

[0036] It should be noted that those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments without conflict. Unless otherwise defined, the technical or scientific terms involved in this invention should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0037] The terms "a," "an," "a kind," "the," and similar words used in this utility model do not indicate quantity limitation and can represent singular or plural. The terms "comprising," "including," "having," and any variations thereof used in this utility model are intended to cover non-exclusive inclusion; the terms "first," "second," "third," etc. used in this utility model are merely to distinguish similar objects and do not represent a specific ordering of objects.

[0038] Existing zero-flux current transformers have the following problems: Current zero-flux current transformers typically employ a horizontal mounting structure using a through-wall bushing as the carrier. While this design can achieve high-voltage direct current measurement, it occupies a large area. With the increasing prevalence of compact substations, the traditional design of zero-flux current transformers, due to its size and layout limitations, is revealing more and more application limitations. Furthermore, the electrical insulation between the high-voltage direct current and the zero-flux coil in traditional designs relies on the bushing. This structure is insufficient to meet the miniaturization and integration requirements of compact substations, and it is difficult to meet the market demand for efficient and compact electrical components.

[0039] Based on the above problems, this utility model proposes a zero-flux current transformer. The technical solution, working principle and technical effects of this utility model are described in detail below with reference to specific embodiments.

[0040] Example 1

[0041] like Figure 2 As shown, this utility model describes a zero-flux current transformer, including a housing 2, an insulating bushing 6, a base, and a transformer body. The transformer body is vertically mounted inside the housing 2, and the primary conductor 3 is disposed inside the transformer body to carry high-voltage direct current. The zero-flux coil 4 is installed at the upper end inside the transformer body, capable of sensing the magnetic field generated by the high-voltage direct current flowing through the primary conductor 3 and outputting a secondary current.

[0042] In this embodiment, the zero flux coil 4 is located inside a shield 5 disposed within the main body of the current transformer. The shield 5 is grounded, thereby placing the zero flux coil 4 at ground potential. This design effectively prevents electrical interference and noise from affecting the zero flux coil 4, improving the measurement accuracy and stability of the current transformer.

[0043] Meanwhile, the transformer is filled with SF6 gas 9, and the zero flux coil 4 is in an SF6 gas insulating environment. SF6 gas 9 is used to provide electrical insulation between the primary conductor 3 and the zero flux coil 4, further improving the safety and reliability of the transformer.

[0044] Furthermore, to buffer the pressure exerted on the zero-flux coil 4 by the SF6 gas 9 filling the transformer, a buffer layer is provided outside the zero-flux coil 4. In this embodiment, the buffer layer is a silicone rubber coating (not shown in the figure) cast onto the outside of the zero-flux coil 4. The silicone rubber coating has good buffering effect and insulation properties, and can effectively protect the zero-flux coil 4 from the influence of internal gas pressure.

[0045] The transformer body is connected in series in the DC circuit system via primary conductor 3. When a high-voltage DC current flows through primary conductor 3, the zero-flux coil 4 can sense the current and output a secondary current. By introducing the secondary current into the zero-flux electronic module (not shown in the figure) through a cable, an ideal secondary signal can be output.

[0046] A rupture disc 1 is also installed on the upper part of the housing 2 to release SF6 gas 9, protecting the housing 2 and the insulating sleeve 6. A density relay 8 is installed on the base to detect changes in the density of SF6 gas 9. When the density of SF6 gas 9 drops to a certain level, the density relay 8 will issue an alarm signal to remind maintenance personnel to replenish SF6 gas 9 in time. In addition, a secondary terminal box 7 is also installed on the base for connecting and transmitting secondary signals output by the zero flux electronic module.

[0047] Example 2

[0048] This embodiment has the same basic structure as Embodiment 1, except for the material and structure of the insulating sleeve 6. In this embodiment, the insulating sleeve 6 is a composite insulating sleeve, with its outer surface coated with glass fiber and a silicone rubber shed. This composite insulating sleeve has higher insulation strength and mechanical strength, and can better withstand the influence of high-voltage direct current and the external environment.

[0049] In light of the above structural description, and to more clearly illustrate the technical solution of this application, the working principle of the wafer baking machine of this application is explained below:

[0050] The transformer body is vertically mounted inside the housing 2. Its core components are the primary conductor 3 and the zero flux coil 4. The primary conductor 3 is located inside the transformer body and is used to carry high-voltage direct current. When the high-voltage direct current flows through the primary conductor 3, a corresponding magnetic field is generated.

[0051] The zero-flux coil 4 is installed at the upper end inside the transformer body and is located within the shield 5. The shield 5 is grounded, placing the zero-flux coil 4 at ground potential. This design effectively prevents electrical interference and noise from affecting the zero-flux coil 4, ensuring the accuracy and stability of the measurement. The zero-flux coil 4 can sense the magnetic field generated by the high-voltage direct current in the primary conductor 3 and output a secondary current accordingly.

[0052] The transformer is filled with SF6 gas 9, and the zero-flux coil 4 is insulated and surrounded by SF6 gas 9. SF6 gas 9 provides electrical insulation between the primary conductor 3 and the zero-flux coil 4, improving the safety and reliability of the transformer. To buffer the gas pressure generated by SF6 gas 9 on the zero-flux coil 4, a silicone rubber coating is applied to the outside of the zero-flux coil 4 as a buffer layer to protect it from the influence of internal gas pressure.

[0053] When a high-voltage direct current flows through the primary conductor 3, the zero-flux coil 4 induces a current and outputs a secondary current. This secondary current is introduced into the zero-flux electronic module through a cable, and after processing, it can output an ideal secondary signal.

[0054] In addition, a rupture disc 1 installed on the upper part of the housing 2 is used to release SF6 gas 9 when necessary to protect the housing 2 and the insulating sleeve 6. A density relay on the base monitors changes in the density of SF6 gas 9; when the density drops to a certain level, it will issue an alarm signal to remind maintenance personnel to replenish SF6 gas 9 in a timely manner. A secondary terminal box 7 is also provided on the base for connecting and transmitting secondary signals output from the zero-flux electronic module.

[0055] In summary, this zero-flux current transformer carries high-voltage DC current through the primary conductor 3, and the zero-flux coil 4 induces a magnetic field and outputs a secondary current. After processing by the zero-flux electronic module, it outputs an ideal secondary signal. At the same time, the internal SF6 gas 9 and the buffer layer, shielding cover 5 and other structures ensure the safety, reliability and measurement accuracy of the transformer.

[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

[0057] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A zero flux current transformer characterized by, include: The housing (2), the insulating sleeve (6) and the base, wherein the upper part of the insulating sleeve (6) is connected to the housing (2) and communicates with the interior of the housing (2); The transformer body is vertically mounted and disposed inside the housing (2); The primary conductor (3) is disposed inside the transformer body and is used to carry high voltage direct current; The zero flux coil (4) is installed inside the transformer body and located at the upper end of the transformer body. The zero flux coil (4) is used to sense the magnetic field generated by the high voltage DC current flowing through the primary conductor (3) and output the secondary current. The zero flux coil (4) is located inside the shield (5) set inside the transformer body. The shield (5) is grounded, so that the zero flux coil (4) is at ground potential. The transformer body is filled with SF6 gas (9); a buffer layer is provided outside the zero flux coil (4), which is used to buffer the gas pressure generated by the SF6 gas (9) inside the transformer body on the zero flux coil (4). A density relay is installed on the base to detect changes in the density of SF6 gas (9).

2. The zero flux current transformer of claim 1, wherein, The zero flux coil (4) is in an environment insulated by SF6 gas (9), which is used to provide electrical insulation between the primary conductor (3) and the zero flux coil (4).

3. The zero flux current transformer of claim 1, wherein, The buffer layer is a silicone rubber coating cast on the outside of the zero flux coil (4).

4. The zero flux current transformer of any one of claims 1 to 3, wherein, The main body of the transformer is connected in series in the DC circuit system through a primary conductor (3). When a high voltage DC current flows through the primary conductor (3), the zero flux coil (4) senses the current and outputs a secondary current. The secondary current is introduced into the zero flux electronic module through a cable and outputs a secondary signal.

5. The zero flux current transformer of claim 1, wherein, The upper part of the housing (2) is equipped with a rupture disc (1) for releasing SF6 gas (9) to protect the housing (2) and the insulating sleeve (6).

6. The zero flux current transformer of claim 1, wherein, The insulating sleeve (6) is a composite insulating sleeve, and the outer surface of the composite insulating sleeve is cast with glass fiber of silicone rubber umbrella skirt.

7. The zero flux current transformer of claim 1, wherein, The base is also equipped with a secondary terminal box (7) for connecting and transmitting the secondary signals output by the zero flux electronic module.

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