High-precision clamp-on current transformer

Abstract

The application discloses a high-precision clamp-on current transformer, comprising two half-clamp-on shell mechanisms, which are hingedly connected with each other; two winding units, which are oppositely arranged in the two half-clamp-on shell mechanisms, and a coil is wound outside the winding unit; the coil comprises a secondary main coil and a compensation coil for offsetting the magnetic resistance of the secondary main coil; the coil density of the compensation coil in each part of the winding unit is determined based on the magnetic resistance of each position, so that the measurement accuracy of the high-precision clamp-on current transformer at any position in the area surrounded by the clamp-on current transformer during work is equal; and a leveling mechanism is elastically arranged between the winding unit and the half-clamp-on shell mechanism, and the leveling mechanism is used for enabling the end-to-end surface contact of the two winding units. The application can improve the measurement accuracy of the clamp-on current transformer.

Description

Technical Field

[0001] This invention relates to the field of power detection technology, and in particular to a high-precision clamp-on current transformer. Background Technology

[0002] Clamp-on current transformers, through their unique hinged magnetic circuit structure (i.e., the "jaw"), allow users to measure the conductor under test directly by pressing the clamp arm to separate the winding unit without interrupting power. This portable design greatly improves field work efficiency and is widely used for detecting parameters such as current, phase, and energy in 35kV and below high-voltage lines.

[0003] However, existing clamp-on current transformers face significant technical bottlenecks in achieving high-precision measurements. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, the invention proposes a high-precision clamp-on current transformer, which can improve the measurement accuracy of the clamp-on current transformer.

[0005] A high-precision clamp-on current transformer according to an embodiment of the present invention includes: Two semi-clamping housing mechanisms are hinged together. Two winding units are located within the two semi-clamp housing mechanisms and are arranged opposite each other. A coil is wound around the outside of the winding unit. The coil includes a secondary main coil and a compensation coil for canceling the magnetic reluctance of the secondary main coil. The coil density of the compensation coil in each part of the winding unit is determined based on the magnetic reluctance at each position, so as to make the measurement accuracy of any position in the area enclosed by the jaws of the high-precision clamp current transformer equal when it is working. A leveling mechanism is elastically disposed between the winding unit and the semi-clamp housing mechanism, and the leveling mechanism is used to make the ends of the two winding units in surface contact.

[0006] In one embodiment, the semi-clamp-shaped housing mechanism includes a shielding housing, the winding unit is located inside the shielding housing, and a wire outlet hole is provided in the middle of the shielding housing for the coil wire to exit; one end of the leveling mechanism is connected to the winding unit, and the other end of the leveling mechanism is connected to the inner surface of the shielding housing.

[0007] In one embodiment, the semi-clamping housing mechanism further includes a clamping end housing and a movable clamping arm housing; the clamping end housing and the movable clamping arm housing are adjustablely connected; the shielding housing is located in the cavity formed by the clamping end housing and the movable clamping arm housing, and is adjustablely connected to the inner wall of the cavity.

[0008] In one embodiment, the contact surface between the clamp-shaped end housing and the moving clamp arm housing is an arc-shaped curved surface; the clamp-shaped end housing is used to drive the shield housing to adjust its position.

[0009] In one embodiment, the shielding housing is made of a soft magnetic material to block power frequency interference signals for the winding unit.

[0010] In one embodiment, the coil density of the compensation coil at the two ends of the winding unit is greater than the coil density at the ends of the winding unit.

[0011] In one embodiment, the leveling mechanism includes a spring and a spring retainer, one end of the spring retainer being fixedly connected to the winding unit, the other end of the spring retainer being connected to one end of the spring, and the other end of the spring being connected to the semi-clamp housing mechanism.

[0012] In one embodiment, the outer surfaces of the two winding units are respectively fixedly connected to the four spring fixing members, and the positions of the spring fixing members are structurally one-to-one to balance the forces on the two winding units.

[0013] In one embodiment, both winding units include a compensation winding unit and a secondary main winding unit; wherein, the compensation winding unit is used to wind the compensation coil; the secondary main winding unit is used to wind the secondary main coil; one end of the compensation winding unit is fixedly connected to the corresponding secondary main winding unit, and the other end of the compensation winding unit is used to contact the other end face of the other compensation winding unit.

[0014] In one embodiment, the movable clamp arm housings are connected by a hinged spring hinge.

[0015] The high-precision clamp-on current transformer according to embodiments of this application has at least the following beneficial effects: by comprising: two semi-clamp-shaped housing mechanisms hinged together; two winding units located within the two semi-clamp-shaped housing mechanisms and arranged opposite to each other, wherein a coil is wound around the outside of each winding unit, the coil including a secondary main coil and a compensation coil for canceling the magnetic reluctance of the secondary main coil, wherein the coil density of the compensation coil in each part of the winding unit is determined based on the magnetic reluctance at each position, for ensuring that the measurement accuracy of any position within the area enclosed by the clamp jaws of the high-precision clamp-on current transformer is equal during operation; and a leveling mechanism elastically disposed between the winding unit and the semi-clamp-shaped housing mechanism, the leveling mechanism being used to make the ends of the two winding units in surface contact, thereby improving the measurement accuracy of the clamp-on current transformer. Attached Figure Description

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the external structure of a high-precision clamp-on current transformer according to an embodiment of the present invention; Figure 2 This is a cross-sectional structural diagram of a high-precision clamp-on current transformer according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the clamp-shaped portion of a high-precision clamp-on current transformer with a winding unit and a coil, according to an embodiment of the present invention. Figure 4 This is a cross-sectional schematic diagram of the clamp-shaped portion of the high-precision clamp-on current transformer with a winding unit and a coil, according to an embodiment of the present invention. Figure 5 This is an exploded view of the structure of a high-precision clamp-on current transformer with a winding unit and a coil at one angle, according to an embodiment of the present invention. Figure 6 This is an exploded view of the structure of the clamp-shaped portion of the high-precision clamp-on current transformer with winding unit and coil from another angle, according to an embodiment of the present invention. Figure 7 This is a schematic diagram of the structure of the clamp-on end housing of the high-precision clamp-on current transformer according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the shielding housing of a high-precision clamp-on current transformer according to an embodiment of the present invention.

[0017] Figure label: The semi-clamp-shaped housing mechanism 100, the clamp-shaped end housing 110, the arc-shaped curved surface 111, the movable clamp arm housing 120, the shielding housing 130, and the cable outlet through hole 131; Winding unit 200, compensating winding unit 210, first compensating winding unit 210a, second compensating winding unit 210b, secondary main winding unit 220; Leveling mechanism 300, spring 310, spring fixing part 320. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] In the description of the invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0020] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0021] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0022] In the field of power testing, clamp-on current transformers, with their unique hinged magnetic circuit structure (i.e., the "jaw"), offer users the convenience of measurement without power interruption. Users simply press the clamp arm to separate the winding unit, pass the conductor to be tested through the jaw, and then close it to complete the measurement. This portable design greatly improves field efficiency, making it widely used for detecting parameters such as current, phase, and energy in 35kV and below high-voltage lines. However, existing clamp-on current transformers face significant technical bottlenecks in high-precision measurement. On the one hand, the uneven magnetic reluctance distribution of the winding unit leads to variations in measurement accuracy at different locations within the area enclosed by the jaw, failing to meet the requirements of applications demanding high measurement accuracy. On the other hand, the contact method at the ends of the winding unit is often suboptimal, potentially exhibiting gaps or non-surface contact, which affects the integrity and stability of the magnetic circuit, thereby reducing measurement accuracy.

[0023] To address this, this invention proposes a high-precision clamp-on current transformer that overcomes the shortcomings of existing clamp-on current transformers in high-precision measurement. It solves the problem of measurement accuracy differences caused by uneven magnetic reluctance distribution in the winding units, as well as the problem of measurement accuracy being affected by imperfect contact at the ends of the winding units, thereby improving the measurement accuracy of the clamp-on current transformer. Specifically, the core solution of this invention is to use a compensation coil and a leveling mechanism to improve measurement accuracy. The "compensation coil" refers to a coil used to cancel the magnetic reluctance of the secondary main coil. Its coil density in each part of the winding unit is determined based on the magnetic reluctance at each position, with the aim of ensuring that the measurement accuracy is equal at any position within the area enclosed by the clamp jaws during operation. The "leveling mechanism" is a device elastically positioned between the winding unit and the semi-clamp housing mechanism to achieve surface contact between the ends of the two winding units.

[0024] The following is in conjunction with the appendix Figure 1-8 This invention provides a detailed description of the high-precision clamp-on current transformer according to embodiments of the present invention.

[0025] Reference Figure 1 and Figure 2 This invention proposes a high-precision clamp-on current transformer, comprising: Two semi-clamping housing mechanisms 100 are hinged to each other; Two winding units 200 are located within two semi-clamp housing mechanisms 100 and are arranged opposite each other. A coil is wound around the outside of the winding unit 200. The coil includes a secondary main coil and a compensation coil for canceling the magnetic reluctance of the secondary main coil. The coil density of the compensation coil in each part of the winding unit 200 is determined based on the magnetic reluctance at each position, so as to make the measurement accuracy of any position in the area enclosed by the jaws of the high-precision clamp current transformer equal when it is working. The leveling mechanism 300 is elastically disposed between the winding unit 200 and the semi-clamp housing mechanism 100. The leveling mechanism is used to make the ends of the two winding units 200 in surface contact.

[0026] Specifically, the high-precision clamp-on current transformer of this application embodiment includes two semi-clamp-shaped housing mechanisms 100 that are hinged together, thereby facilitating the opening and closing operation of the transformer. Two winding units 200 are respectively located within the two semi-clamp-shaped housing mechanisms 100 and are arranged opposite to each other. A coil is wound on the outside of the winding unit 200, including a secondary main coil 220 and a compensation coil 210. The coil density of the compensation coil 210 in each part of the winding unit is adjusted according to the magnetic reluctance at each position of the winding unit 200. Optionally, at the two ends of the winding unit, due to the larger magnetic reluctance, the coil density of the compensation coil is greater than that at the non-winding unit ends. This design can effectively cancel the magnetic reluctance of the secondary main coil and the magnetic reluctance at the two ends of the winding unit (e.g., the air gap between the winding units when the clamp is closed), so that the measurement accuracy can remain consistent within the area enclosed by the clamp jaws, regardless of the position of the conductor being measured.

[0027] Furthermore, the leveling mechanism 300 is elastically disposed between the winding unit 200 and the semi-clamp housing mechanism 100. Optionally, the leveling mechanism 300 balances the forces on the two winding units 200 during clamping operation, thereby achieving the effect of surface contact between the end faces of the winding units 200 during clamping. That is, by achieving surface contact between the ends of the two winding units 200, the integrity and stability of the magnetic circuit are ensured.

[0028] The high-precision clamp-on current transformer of this application embodiment includes: two semi-clamp-shaped housing mechanisms 100, which are hinged to each other; two winding units 200, which are respectively located inside the two semi-clamp-shaped housing mechanisms 100 and arranged opposite to each other, with coils wound on the outside of the winding units 200. The coils include a secondary main coil and a compensation coil for canceling the magnetic reluctance of the secondary main coil. The coil density of the compensation coil in each part of the winding unit 200 is determined based on the magnetic reluctance at each position, so as to make the measurement accuracy of any position in the area enclosed by the clamp jaws of the high-precision clamp-on current transformer equal when it is working; and a leveling mechanism 300, which is elastically disposed between the winding units 200 and the semi-clamp-shaped housing mechanisms 100. The leveling mechanism 300 is used to make the ends of the two winding units 200 in surface contact, thereby improving the measurement accuracy of the clamp-on current transformer. This application solves the problem of low measurement accuracy of existing clamp-on current transformers by using the compensation coil to cancel out magnetic reluctance and the leveling mechanism to make the end face of the winding unit 200 contact.

[0029] In one exemplary embodiment, refer to Figures 2 to 8The semi-clamp-shaped housing mechanism 100 includes a shielding housing 130, a winding unit 200 located inside the shielding housing 130, and a wire outlet through hole 131 provided in the middle of the shielding housing 130 for coil wire outlet; one end of the leveling mechanism 300 is connected to the winding unit 200, and the other end of the leveling mechanism 300 is connected to the inner surface of the shielding housing 130.

[0030] Specifically, the semi-clamp-shaped housing mechanism 100 includes a shielding housing 130 and an outer housing sleeved outside the shielding housing 130. The outer housing is made of insulating material. The winding unit 200 is located inside the shielding housing 130 and is elastically connected to the winding unit 200 through a leveling mechanism 300. A wire outlet hole 131 is provided in the middle of the shielding housing 130 for the signal wire of the coil to exit and output the current measurement value. (Refer to...) Figure 8 The through-hole 131 is located in the middle of the shielding housing 130. The winding units 200 on both sides and their coils are fitted into the corresponding shielding housings 130. When the clamps are closed, the shielding housings 130 on both sides form a sealed space except for the through-hole 131. Figure 3 As shown, this allows for better shielding of power frequency signals.

[0031] Optionally, the shielding housing 130 is made of soft magnetic material to block power frequency interference signals for the winding unit 200.

[0032] In one exemplary embodiment, refer to Figure 2 The semi-clamping housing mechanism 100 also includes a clamping end housing 110 and a movable clamping arm housing 120; the clamping end housing 110 and the movable clamping arm housing 120 are adjustablely connected; the shielding housing 130 is located in the cavity formed by the clamping end housing 110 and the movable clamping arm housing 120, and is adjustablely connected to the inner wall of the cavity.

[0033] Specifically, the semi-clamp housing mechanism 100 also includes a clamp-shaped end housing 110 and a moving clamp arm housing 120; the clamp-shaped end housing 110 is adjustablely connected to the moving clamp arm housing 120 through a fine-tuning structure; the shield housing 130 is located in the cavity formed by the clamp-shaped end housing 110 and the moving clamp arm housing 120, and is adjustablely connected to the inner wall of the cavity. Through the aforementioned adjustable structure, the clamp-shaped end of the clamp-type current transformer can be finely adjusted in terms of position and orientation as needed during operation, thereby driving the internal shield housing 130 to adjust in position, so that the two shield housings 130 can be tightly closed during operation, ensuring a sealed environment except for the through hole 131, thereby improving the shielding performance of the shield housing 130 during operation of the clamp-type current transformer, and improving the measurement accuracy of the current transformer.

[0034] Optionally, the contact surface between the clamp-shaped end housing and the moving clamp arm housing is an arc-shaped curved surface 111; the clamp-shaped end housing is used to drive the shielding housing to adjust its position. Specifically, the specific structure of the arc-shaped curved surface 111 is as follows: Figure 5 and Figure 7 The curved surface is used to allow for positional adjustment between the clamp-shaped end housing 110 and the moving clamp arm housing 120. That is, through the contact surface structure of the curved surface, when an external force is applied to the clamp-shaped end housing 110, the clamp-shaped end housing 110 drives the shield housing 130 to adjust its position, thereby making the docking of the left and right shield housings more precise and avoiding misalignment, air gaps and crevices between the shield housings 130 when the clamps are closed, thus improving the shielding performance.

[0035] The shielding housing 130 and the clamp-shaped end housing 110 with an arc-shaped curved surface for fine-tuning the position of the shielding housing 130 significantly improve the power frequency magnetic field immunity. Optionally, the power frequency magnetic field immunity test of this application shall be conducted under the following conditions: a) The test shall be applied to the three vertical planes of the calibrator, and an external magnetic induction shall be generated by a current of the same frequency as the voltage applied to the test, with the calibrator under test placed at the center of the induction coil. 1) The induction coil conforms to the requirements of 6.3.3-a in IEC 61000-4-8:2009; 2) Immersion test method: magnetic induction intensity is 0.5mT (400A / m); 3) Change the direction and phase of the external magnetic induction on the local calibrator, and determine the condition under which the local calibrator is under the most unfavorable influence of the external power frequency magnetic field by the maximum deviation of the local calibrator error. b) Test duration: 1 min; c) The voltage line is subject to a reference voltage, the current line is subject to a rated current, and the power factor is 1.

[0036] During the test, a temporary decrease or loss of performance of the calibration instrument is permissible. The error change in the power frequency magnetic field immunity test should meet the requirements of the highest standard.

[0037] In one exemplary embodiment, the coil density of the compensation coil at the two edge positions of the winding unit 200 is greater than the coil density at the two edge positions of the non-winding unit 200.

[0038] Specifically, by employing the technical feature of determining coil density based on reluctance using a compensation coil, the measurement accuracy difference within the area enclosed by the clamps during operation of the high-precision clamp-on current transformer is reduced to an extremely small range (detection method: multiple measurements are performed at different positions using a standard current source, and the deviation of the measurement results is calculated). The measurement accuracy at any position is essentially equal, greatly improving measurement accuracy. It is understandable that, due to the higher reluctance at both ends of the winding unit 200, the density of the compensation coil should also be higher. Optionally, the specific reluctance of the winding unit at different positions can be obtained experimentally.

[0039] Meanwhile, the leveling mechanism 300 enables surface contact between the ends of the two winding units, ensuring the stability of the magnetic circuit and significantly improving measurement accuracy compared to existing technologies. Furthermore, the shielding housing 130, made of soft magnetic material, effectively blocks power frequency interference signals, further enhancing the reliability and stability of the measurement.

[0040] In one exemplary embodiment, refer to Figure 2 The leveling mechanism 300 includes a spring 310 and a spring fixing member 320. One end of the spring fixing member 320 is fixedly connected to the winding unit 200, and the other end of the spring fixing member 320 is connected to one end of the spring 310. The other end of the spring 310 is connected to the semi-clamp-shaped housing mechanism 100.

[0041] Specifically, the leveling mechanism 300 includes a spring 310 and a spring fixing member 320. One end of the spring fixing member 320 is fixedly connected to the winding unit 200, and the other end is connected to one end of the spring 310. The other end of the spring 310 is connected to the semi-clamp-shaped housing mechanism 100. Optionally, refer to... Figure 6 Each of the two winding units 200 has its outer surface fixedly connected to four spring fixing members 320, and the positions of the spring fixing members 320 are structurally one-to-one, which balances the forces on the two winding units 200. Specifically, since each of the two winding units 200 has four spring fixing members 320 on its outer surface, a high-precision clamp-on current transformer has a total of eight elastic fixing members 320 and their corresponding springs 310. Through the action of the leveling mechanism 300, surface contact can be achieved between the ends of the two winding units 200, ensuring the integrity and stability of the magnetic circuit.

[0042] In one exemplary embodiment, refer to Figure 4 and Figure 6Both winding units 200 include a compensation winding unit 210 and a secondary main winding unit 220; wherein, the compensation winding unit 210 is used to wind the compensation coil; the secondary main winding unit 220 is used to wind the secondary main coil; one end of the compensation winding unit 210 is fixedly connected to the corresponding secondary main winding unit 220, and the other end of the compensation winding unit 210 is used to contact the other end face of the other compensation winding unit 210.

[0043] Specifically, both winding units 200 include a compensation winding unit 210 and a secondary main winding unit 220; wherein, the compensation winding unit 210 is used to wind a compensation coil; the secondary main winding unit 220 is used to wind a secondary main coil; one end of the compensation winding unit 210 is fixedly connected to the corresponding secondary main winding unit 220, and the other end of the compensation winding unit 210 is used to contact the other end face of the other compensation winding unit 210; wherein, referring to Figure 4 The compensation winding unit 210 includes a first compensation winding unit 210a disposed above the secondary main winding unit 220 and a second compensation winding unit 210b disposed below the secondary main winding unit 220. Both compensation winding units are wound with compensation coils, and the coil winding density is determined based on the magnetic reluctance at each position. Optionally, the coil density is higher at the part closer to the contact surface of the winding unit.

[0044] In one exemplary embodiment, the movable jaw arm housings 120 are connected by a hinged spring hinge. Specifically, the left and right movable jaw arm housings 120 are connected by a hinged spring hinge to drive the jaws to open and close for operation.

[0045] It is understood that the aforementioned high-precision clamp-on current transformer includes a semi-clamp-like housing mechanism comprising a shield housing 130, a clamp-like end housing 110, and a moving clamp arm housing 120. The shield housing 130, made of soft magnetic material, is located within the cavity formed by the clamp-like end housing 110 and the moving clamp arm housing 120, and is adjustablely connected to the inner wall of the cavity. A through-hole for coil wiring is provided in the middle of the shield housing 130. The clamp-like end housing 110 and the moving clamp arm housing 120 are adjustablely connected, and their contact surface is an arc-shaped curved surface. The clamp-like end housing 110 can drive the shield housing 130 to adjust its position and orientation, thereby further optimizing the position and orientation of the shield housing 130, improving anti-interference capability, and ultimately improving measurement accuracy. The moving clamp arm housings 120 are connected by a hinged spring hinge for convenient user operation.

[0046] The implementation steps of this application are described in detail below with reference to a specific embodiment: Component preparation: The system consists of two opposing semi-clamping housings: a shielding housing, a clamping end housing, and a moving clamping arm housing. The shielding housing is made of a soft magnetic material, such as permalloy (enough to effectively block power frequency interference signals), and has a 10mm diameter through-hole in the center (this diameter is chosen to facilitate coil routing without compromising shielding effectiveness due to an excessively large hole). The clamping end housing and the moving clamping arm housing are made of aluminum alloy, and their contact surface is an arc-shaped curve for easy position adjustment. The moving clamping arm housing is hinged together by a spring (a standard cylindrical helical compression spring with a spring constant of 5N / m can be used to ensure convenient opening and closing of the moving clamping arm).

[0047] Winding Units: Two winding units are located within two semi-clamp-shaped housing mechanisms and are arranged opposite each other. Each winding unit includes a compensation winding unit and a secondary main winding unit. The cores of the compensation winding unit and the secondary main winding unit are made of permalloy laminated together (permalloy has the characteristics of low hysteresis loss and high permeability, which can improve the performance of the current transformer). The compensation winding unit is used to wind the compensation coil, and the secondary main winding unit is used to wind the secondary main coil. One end of the compensation winding unit is fixedly connected to the corresponding secondary main winding unit by welding, and the other end is used to contact the other end face of the other compensation winding unit.

[0048] Coil: The secondary main coil is wound with enameled copper wire, and the number of turns is determined according to actual needs. The compensation coil is also wound with enameled copper wire, and the coil density at the edges of the winding unit is greater than the coil density at the edges of the non-winding unit. Experimental tests show that the number of coil turns at the edges of the winding unit is 20% more than that at the non-edge positions (this ratio was obtained through multiple experiments and optimization, and can effectively counteract the magnetic reluctance of the secondary main coil).

[0049] Leveling Mechanism: The leveling mechanism consists of springs and spring retainers. The spring retainers are made of stainless steel, with one end bolted to the winding unit and the other end welded to one end of the spring. The springs are cylindrical helical compression springs with an elastic coefficient of 3 N / m (this coefficient ensures contact between the end faces of the winding units without excessive elasticity affecting the stability of the transformer). The outer surfaces of both winding units are respectively fixedly connected to four spring retainers, whose positions are structurally one-to-one to ensure force balance between the two winding units.

[0050] Assembly steps: First, wind the secondary main coil and the compensation coil onto their respective winding units, paying attention to the coil density distribution of the compensation coil. Install the winding units into the shielding housing, and connect the other end of the leveling mechanism spring to the inner surface of the shielding housing using adhesive or other methods to ensure an elastic connection between the winding units and the shielding housing.

[0051] Then, the shielding housing is installed into the cavity formed by the clamp-shaped end housing and the moving clamp arm housing. During the installation process, the shielding housing and the inner wall of the cavity can be adjusted to facilitate subsequent posture adjustment.

[0052] Finally, the two semi-clamp housing mechanisms are connected by a hinged spring hinge to complete the assembly of the high-precision clamp current transformer.

[0053] Effect verification: Test environment: In a laboratory environment, a standard current source is used to provide a stable current signal to simulate the actual working conditions of high voltage lines of 35kV and below.

[0054] Control setup: A common clamp-on current transformer found on the market was selected as the control.

[0055] Measuring instrument: Use a high-precision multimeter to measure the current value.

[0056] Evaluation criteria: The measurement error is calculated based on the current value provided by a standard current source.

[0057] Test procedure: The high-precision clamp-on current transformer of this embodiment and the ordinary clamp-on current transformer of the control were used to measure the current at different locations. The measurement was performed 10 times at each location and the average value was taken.

[0058] Test results: The high-precision clamp-on current transformer of this embodiment exhibits equal and significantly higher measurement accuracy at any position within the area enclosed by the clamp jaws compared to the conventional clamp-on current transformer. Furthermore, observation of the magnetic circuit stability reveals that the transformer winding unit end face of this embodiment has good contact, resulting in higher magnetic circuit integrity and stability.

[0059] Furthermore, the shielding housing can be made of other soft magnetic materials, such as iron-silicon-aluminum alloys, as long as they can effectively block power frequency interference signals. The springs in the leveling mechanism can use springs with different elastic coefficients, but it is necessary to ensure that the ends of the two winding units achieve surface contact and force balance. Other types of springs, such as rubber springs, can also be used in the leveling mechanism, but their elastic performance and stability must be guaranteed. The hinge springs between the moving clamp arm housings can also be of any type, as long as they facilitate opening and closing operations.

[0060] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high-precision clamp-on current transformer, characterized in that, include: Two semi-clamping housing mechanisms are hinged together. Two winding units are located within the two semi-clamp housing mechanisms and are arranged opposite each other. A coil is wound around the outside of the winding unit. The coil includes a secondary main coil and a compensation coil for canceling the magnetic reluctance of the secondary main coil. The coil density of the compensation coil in each part of the winding unit is determined based on the magnetic reluctance at each position, so as to make the measurement accuracy of any position in the area enclosed by the jaws of the high-precision clamp current transformer equal when it is working. A leveling mechanism is elastically disposed between the winding unit and the semi-clamp housing mechanism, and the leveling mechanism is used to make the ends of the two winding units in surface contact.

2. The high-precision clamp-on current transformer according to claim 1, characterized in that, The semi-clamp-shaped housing mechanism includes a shielding housing, the winding unit is located inside the shielding housing, and a wire outlet hole is provided in the middle of the shielding housing for the coil wire to exit; one end of the leveling mechanism is connected to the winding unit, and the other end of the leveling mechanism is connected to the inner surface of the shielding housing.

3. The high-precision clamp-on current transformer according to claim 2, characterized in that, The semi-clamp-shaped housing mechanism further includes a clamp-shaped end housing and a movable clamp arm housing; the clamp-shaped end housing and the movable clamp arm housing are adjustablely connected; the shield housing is located in the cavity formed by the clamp-shaped end housing and the movable clamp arm housing, and is adjustablely connected to the inner wall of the cavity.

4. The high-precision clamp-on current transformer according to claim 3, characterized in that, The contact surface between the clamp-shaped end housing and the moving clamp arm housing is an arc-shaped curved surface; the clamp-shaped end housing is used to drive the shield housing to adjust its position.

5. The high-precision clamp-on current transformer according to claim 2, characterized in that, The shielding housing is made of soft magnetic material and is used to block power frequency interference signals for the winding unit.

6. The high-precision clamp-on current transformer according to claim 1, characterized in that, The coil density of the compensation coil at the two ends of the winding unit is greater than the coil density at the ends of the winding unit.

7. The high-precision clamp-on current transformer according to any one of claims 1 to 6, characterized in that, The leveling mechanism includes a spring and a spring fixing member. One end of the spring fixing member is fixedly connected to the winding unit, and the other end of the spring fixing member is connected to one end of the spring. The other end of the spring is connected to the semi-clamp-shaped housing mechanism.

8. The high-precision clamp-on current transformer according to claim 7, characterized in that, The outer surfaces of the two winding units are respectively fixedly connected to the four spring fixing members. The positions of the spring fixing members are structurally one-to-one, which is used to balance the forces on the two winding units.

9. The high-precision clamp-on current transformer according to claim 1, characterized in that, Both winding units include a compensation winding unit and a secondary main winding unit; wherein, the compensation winding unit is used to wind the compensation coil; the secondary main winding unit is used to wind the secondary main coil; one end of the compensation winding unit is fixedly connected to the corresponding secondary main winding unit, and the other end of the compensation winding unit is used to contact the other end face of the other compensation winding unit.

10. The high-precision clamp-on current transformer according to claim 3, characterized in that, The movable clamp arm housings are connected by a hinged spring hinge.

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