Portable metering low-voltage current transformer

Abstract

This application relates to a portable low-voltage current transformer, belonging to the technical field of power measurement devices. It includes a transformer body and clamping mechanisms located at the left and right axial ends of the transformer body. Each clamping mechanism includes a housing and a square frame within the housing. The inner walls of the square frame form a square through-hole, the side length of which is larger than the diameter of the through-hole in the transformer body. A first clamping plate, a second clamping plate, a third clamping plate, and a fourth clamping plate are arranged opposite each other within the square through-hole. These clamping plates form a grid pattern and enclose a clamping space. Adjustment mechanisms are provided on the sides of the first, second, third, and fourth clamping plates away from the clamping space. This application improves installation convenience in space-constrained environments and enhances measurement accuracy and applicability in situations where wiring is not centered.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power measuring devices, in particular to a portable low-voltage current transformer. BACKGROUND

[0002] As a key measuring device in the power system, the low-voltage current transformer converts the large current in the primary circuit into a small current that is easy to measure by electromagnetic induction principle, and is widely used in the fields of electric energy metering, relay protection and system monitoring.

[0003] In order to ensure the measurement accuracy, the existing low-voltage current transformer generally adopts a forced centering structure, so that the measured bus or busbar must be accurately centered through the through hole to ensure the symmetry of the magnetic circuit and reduce the measurement error. The current technical solution mainly realizes the centering positioning through a mechanical clamping mechanism. For example, a plurality of linkage baffles or a clamping piece driven by a lead screw are used to clamp the wire from both sides synchronously, so that the wire is fixed on the center axis of the through hole. Although this kind of structure can effectively avoid the magnetic field distortion caused by the inclination of the bus or busbar, it also has significant limitations. In actual installation environment, the space of the power distribution cabinet is often very compact, or it is limited by the existing line layout, so the busbar often needs to be inclined and bent to pass through the current transformer. The forced centering design has poor adaptability in such scenarios, the installation process is cumbersome, and even it cannot be implemented.

[0004] More importantly, in some special test or diagnosis conditions, such as simulating the asymmetric operation state of the power grid or detecting the temporary fault current, it is necessary to intentionally adjust the passing angle of the wire in the low-voltage current transformer to obtain a specific electromagnetic response. The rigid centering structure of the existing technology cannot meet the flexible measurement requirements, which limits the functional expansion and application range of the low-voltage current transformer. SUMMARY

[0005] In order to improve the installation convenience in the space-limited environment and improve the measurement accuracy and applicability in the non-centered wire passing condition, the present application provides a portable low-voltage current transformer.

[0006] The portable low-voltage current transformer provided by the present application adopts the following technical solution:

[0007] A portable low-voltage current transformer, comprising a current transformer body and a clamping mechanism arranged at the left and right ends of the current transformer body in the axial direction, the clamping mechanism comprising a mounting shell and a square frame arranged in the mounting shell, a square through hole penetrating through the mounting shell is surrounded by the inner walls of the square frame, and the side length of the square through hole is greater than the hole diameter of the through hole of the current transformer body.

[0008] The square through hole is provided with a first clamping plate and a second clamping plate, as well as a third clamping plate and a fourth clamping plate arranged opposite each other. The first clamping plate, the second clamping plate, the third clamping plate and the fourth clamping plate are arranged in a "well" shape and enclose a clamping space. An adjustment mechanism is provided on the side of the first clamping plate, the second clamping plate, the third clamping plate and the fourth clamping plate away from the clamping space.

[0009] Optionally, the first clamping plate and the second clamping plate constitute a first clamping assembly, and the third clamping plate and the fourth clamping plate constitute a second clamping assembly. The first clamping assembly and the second clamping assembly are misaligned and one side of them are fitted together.

[0010] The first clamping component is slidably connected to one pair of opposite sidewalls of the square frame along the length direction of the square frame, and the second clamping component is slidably connected to another pair of opposite sidewalls of the square frame along the width direction of the square frame.

[0011] Optionally, the adjustment mechanism includes an adjustment screw and an operating lever. One end of the adjustment screw is rotatably connected to the side of the corresponding clamping plate away from the clamping space, and the other end of the adjustment screw is connected to the operating lever. The square frame is provided with a threaded hole adapted to the adjustment screw, and the mounting housing is provided with a through hole for the operating lever to pass through.

[0012] Optionally, a limiting end plate is fixedly connected between the adjusting screw and the operating lever, and a compression spring is sleeved on the outside of the operating lever. One end of the compression spring abuts against the limiting end plate, and the other end abuts against the inner wall of the housing.

[0013] Optionally, a thin-film piezoelectric sensor is provided on the inner wall of the housing, and the end of the compression spring away from the limiting end plate presses against the sensing end of the thin-film piezoelectric sensor.

[0014] Optionally, the operating lever includes a fixed rod and a hinged rod arranged coaxially. The fixed rod is fixed coaxially with the adjusting screw, and one end of the hinged rod is hinged to the end of the fixed rod away from the adjusting screw via a hinge.

[0015] Optionally, the end of the hinge rod away from the fixed rod is fixed with a rotating part, and the end of the hinge rod near the fixed rod is provided with a guide cone surface.

[0016] Optionally, a control unit is also included, which is signal-connected to each thin-film piezoelectric sensor, and the control unit is configured to calculate the compression length of the corresponding spring based on the measurement data of the thin-film piezoelectric sensors.

[0017] Optionally, the control unit is configured to establish a spatial coordinate system, wherein the mating surfaces of the first and second clamping components in the clamping mechanism at the left end of the current transformer body are taken as the left clamping surface, the left clamping surface is taken as the yz plane, and the direction of the center line of the through hole is taken as the x-axis.

[0018] The control unit is configured to determine the coordinates (0, Δy1, Δz1) of the clamping center point on the left clamping surface and the coordinates (L, Δy2, Δz2) of the clamping center point on the right clamping surface, where L is the distance between the left clamping surface and the right clamping surface, and the right clamping surface is the contact surface of the first clamping component and the second clamping component in the clamping mechanism at the right end of the current transformer body.

[0019] Optionally, the control unit is further configured to calculate the actual current value of the busbar or busbar under test using a current compensation algorithm based on the coordinates of the clamping center point (0, Δy1, Δz1) on the left clamping surface and the coordinates of the clamping center point (L, Δy2, Δz2) on the right clamping surface.

[0020] In summary, this application includes at least one of the following beneficial technical effects:

[0021] 1. By installing clamping mechanisms at both ends of the through-hole in the current transformer body, the spatial position of the busbar or busbar under test is forcibly fixed, solving the core problem of unstable measurement results caused by fluctuations in tilt angle when the wire is not centered. The clamping mechanisms at both ends lock the attitude of the busbar or busbar under test to a constant state, establishing a controllable measurement benchmark for current detection, eliminating the influence of random displacement of the busbar or busbar under test on measurement accuracy, and ensuring the repeatability of the test data. In addition, this design enables low-voltage current transformers to adapt to complex installation environments with limited space, expanding their engineering application range.

[0022] 2. By incorporating a compression spring and a thin-film piezoelectric sensor, the continuous axial pressure applied by the compression spring ensures a tight contact between the threads of the adjusting screw and the threaded hole, generating friction. This effect is similar to using a spring washer on a bolt, effectively resisting vibrations and shocks during equipment operation and preventing the threaded pair from loosening due to vibration, thus ensuring the long-term stability of the clamping position. Furthermore, since the compression of the compression spring is linearly related to the applied pressure, the thin-film piezoelectric sensor can accurately calculate the compression of the spring, which corresponds to the displacement of the clamping plate, by detecting the pressure applied by the spring. This provides crucial feedback signals for the subsequent control unit, making the clamping state quantifiable and monitorable.

[0023] 3. By dividing the operating lever into a fixed lever and a hinged lever connected by a hinge, the operating lever achieves a bendable function. When the extended length of the operating lever may interfere with surrounding components, the hinged lever can rotate around the hinge axis to one side, thereby bending the operating lever at the hinge to avoid obstructing surrounding components. When a turning operation is required, the hinged lever can rotate back around the hinge axis to be coaxial with the fixed lever. This bendable design of the operating lever solves the operational difficulties in confined spaces, improves spatial adaptability, and is especially suitable for compact distribution cabinet environments.

[0024] 4. The use of a guide cone further optimizes the practicality and reliability of the operating lever. When the hinged lever needs to be restored to a coaxial state after bending, the guide cone facilitates quick alignment with the through hole, reducing alignment time and friction loss, and ensuring smooth movement of the operating lever.

[0025] 5. Intelligent management is achieved through the cooperation of the control unit and the thin-film piezoelectric sensor. By processing the data from the thin-film piezoelectric sensor, the control unit can calculate the compression state of the corresponding spring, thereby reflecting the position state of the clamping mechanism. This provides support for error compensation in the clamping posture positioning and current detection of the busbar or busbar under test. The automated processing of the control unit reduces human intervention and improves the reliability of the system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of a convenient metering low-voltage current transformer in use according to an embodiment of this application, wherein the busbar or busbar to be tested is in a non-centered through-core state.

[0027] Figure 2 This is a schematic diagram illustrating the structure of the clamping mechanism in the embodiments of this application.

[0028] Figure 3 This is an exploded view of the overall structure of a convenient metering low-voltage current transformer according to an embodiment of this application.

[0029] Figure 4 This is a structural schematic diagram illustrating the operation lever in a straight state in the embodiments of this application.

[0030] Figure 5 This is a structural diagram illustrating the bending state of the operating lever in the embodiments of this application.

[0031] Figure 6 This is a schematic diagram illustrating the connection principle of the thin-film piezoelectric sensor and the control unit in the embodiments of this application, wherein the dashed lines represent signal connections.

[0032] Explanation of reference numerals in the attached drawings: 1. Current transformer body; 2. Clamping mechanism; 21. Added housing; 211. First housing with holes; 2111. Through hole; 212. Second housing with holes; 22. Square frame; 221. Threaded hole; 23. Square through hole; 24. First clamping assembly; 241. First clamping plate; 242. Second clamping plate; 25. Second clamping assembly; 251. Third clamping plate; 252. Fourth clamping plate; 26. Clamping space; 3. Adjustment mechanism; 31. Adjustment screw; 32. Operating lever; 321. Fixing rod; 322. Hinge rod; 3221. Tightening part; 3222. Guide cone surface; 323. Hinge; 33. Limiting end plate; 4. Compression spring; 5. Thin film piezoelectric sensor; 6. Connecting ear; 61. Fastening bolt; 7. Control unit. Detailed Implementation

[0033] The following combination Figures 1-6 This application will be described in further detail below.

[0034] Example: This application discloses a convenient metering low-voltage current transformer. (Refer to...) Figure 1 and Figure 2 A convenient metering low-voltage current transformer includes a transformer body 1 and clamping mechanisms 2 disposed at the left and right ends of the transformer body 1 along its axial direction. The clamping mechanism 2 includes a mounting housing 21 and a square frame 22 disposed in the mounting housing 21. The inner walls of the square frame 22 form a square through hole 23 penetrating the mounting housing 21. The side length of the square through hole 23 is larger than the diameter of the through hole in the transformer body 1. The square through hole 23 is provided with a first clamping plate 241 and a second clamping plate 242 disposed opposite to each other, as well as a third clamping plate disposed opposite to each other. The first clamping plate 241, the second clamping plate 242, the third clamping plate 251, and the fourth clamping plate 252 are arranged in a "well" shape and enclose a clamping space 26. Adjustment mechanisms 3 are respectively provided on the side of the first clamping plate 241, the second clamping plate 242, the third clamping plate 251, and the fourth clamping plate 252 away from the clamping space 26. Each adjustment mechanism 3 can independently adjust the position of the corresponding clamping plate to achieve clamping of busbars or busbars with different tilt postures and different sizes. In this embodiment, the square frame 22 has a square structure, with its length and width dimensions being equal; the square through hole 23 is directly opposite the through hole of the transformer body 1.

[0035] This metering low-voltage current transformer solves the core problem of unstable measurement results caused by tilt angle fluctuations when the wire is not centered by setting clamping mechanisms 2 at both ends of the through hole of the transformer body 1 to forcibly fix the spatial position of the busbar or busbar under test. The clamping mechanisms 2 at both ends lock the attitude of the busbar or busbar under test to a constant state, establishing a reliable "control variable" condition for current detection, eliminating the influence of random displacement of the busbar or busbar under test on measurement accuracy, and ensuring the repeatability of the detection data. In addition, this design enables the metering low-voltage current transformer to adapt to complex installation environments with limited space, expanding its engineering application range.

[0036] Reference Figure 2 The first clamping plate 241 and the second clamping plate 242 constitute the first clamping assembly 24, and the third clamping plate 251 and the fourth clamping plate 252 constitute the second clamping assembly 25. The first clamping assembly 24 and the second clamping assembly 25 are offset and one side of them are attached to each other. The first clamping assembly 24 is slidably connected to one pair of opposite sidewalls of the square frame 22 along the length direction of the square frame 22, and the second clamping assembly 25 is slidably connected to another pair of opposite sidewalls of the square frame 22 along the width direction of the square frame 22. In this way, the clamping force can be evenly applied to the busbar or busbar under test, preventing deformation of the busbar or busbar caused by single-point stress concentration, while ensuring the stability and reliability of the clamping.

[0037] Reference Figure 2 The adjustment mechanism 3 includes an adjustment screw 31 and an operating lever 32. One end of the adjustment screw 31 is rotatably connected to the side of the corresponding clamping plate away from the clamping space 26, and the other end of the adjustment screw 31 is connected to the operating lever 32. A threaded hole 221 adapted to the adjustment screw 31 is provided on the square frame 22, and a through hole 2111 for the operating lever 32 to pass through is provided on the housing 21. The precise fit between the adjustment screw 31 and the threaded hole 221 provides stable mechanical transmission, allowing the operator to adjust by turning the operating lever 32, thereby reliably locking the corresponding clamping plate in the target position.

[0038] Reference Figure 2A limiting end plate 33 is fixedly connected between the adjusting screw 31 and the operating lever 32. A compression spring 4 is sleeved on the outside of the operating lever 32, with one end of the compression spring 4 abutting against the limiting end plate 33 and the other end abutting against the inner wall of the housing 21. A thin-film piezoelectric sensor 5 is fixed on the inner wall of the housing 21, with the end of the compression spring 4 away from the limiting end plate 33 pressing against the sensing end of the thin-film piezoelectric sensor 5. Through the setting of the compression spring 4 and the thin-film piezoelectric sensor 5, the axial pressure continuously applied by the compression spring 4 keeps the threads of the adjusting screw 31 and the threads of the threaded hole 221 in close contact, generating friction. This effect is similar to using a spring washer on a bolt, which can effectively resist the vibration and impact during equipment operation, prevent the threaded pair from loosening due to vibration, and thus ensure the long-term stability of the clamping position. Furthermore, since the compression of the spring 4 is linearly related to the pressure it is subjected to, the thin-film piezoelectric sensor 5 can accurately calculate the compression of the spring 4 by detecting the pressure applied by the spring 4, which corresponds to the displacement of the clamping plate, making the clamping state quantifiable and monitorable.

[0039] Reference Figures 1-3 To facilitate the installation of the clamping mechanism 2, the housing 21 includes a first perforated housing 211 and a second perforated housing 212. The first and second perforated housings 211 and 212 form cavities to accommodate the thin-film piezoelectric sensor 5 and the movement of the adjustment mechanism 3. Connecting lugs 6 are fixed to the outer circumferential surfaces of the first perforated housing 211, the second perforated housing 212, and the transformer body 1 at both ends. The connecting lugs 6 at both ends of the first perforated housing 211, the second perforated housing 212, and the transformer body 1 are correspondingly provided and detachably fixed together by fastening bolts 61.

[0040] Reference Figure 2 , Figure 4 and Figure 5 The operating lever 32 includes a fixed lever 321 and a hinged lever 322 coaxially arranged. The fixed lever 321 is coaxially fixed with the adjusting screw 31 and has the same thickness. One end of the hinged lever 322 is hinged to the end of the fixed lever 321 away from the adjusting screw 31 via a hinge 323. This achieves the bendable function of the operating lever 32. When the extended length of the operating lever 32 may interfere with surrounding components, the hinged lever 322 can rotate around the hinge axis of the hinge 323, deflecting towards one side of the fixed lever 321, thereby bending the operating lever 32 at the hinge 323 to avoid interference with surrounding components. When a turning operation is required, the hinged lever 322 can rotate back around the hinge axis of the hinge 323 to be coaxial with the fixed lever 321. This bendable design of the operating lever 32 solves the operational difficulties in confined spaces, improves spatial adaptability, and is especially suitable for compact electrical cabinet environments.

[0041] Reference Figure 4 and Figure 5To facilitate gripping and turning by the operator, a turning part 3221 is fixed at the end of the hinge rod 322 away from the fixed rod 321. To further optimize the practicality and reliability of the operating rod 32, a guide cone surface 3222 is provided at the end of the hinge rod 322 near the fixed rod 321. When the hinge rod 322 needs to be restored to a coaxial state after bending, the guide cone surface 3222 facilitates its quick alignment with the through hole 2111, reducing alignment time and friction loss, and ensuring the smoothness of the operating rod 32 during movement.

[0042] Reference Figure 6 The metering low-voltage current transformer also includes a control unit 7, which is signal-connected to each thin-film piezoelectric sensor 5. The control unit 7 is configured to calculate the compression length of the corresponding compression spring 4 based on the measurement data of the thin-film piezoelectric sensor 5.

[0043] Reference Figure 2 and Figure 6 The control unit 7 is configured to establish a spatial coordinate system, wherein the mating surface of the first clamping component 24 and the second clamping component 25 in the clamping mechanism 2 at the left end of the mutual inductor body 1 is the left clamping surface, the left clamping surface is the yz plane, and the direction of the center line of the through hole is the x-axis.

[0044] The control unit 7 is configured to determine the coordinates (0, Δy1, Δz1) of the clamping center point on the left clamping surface and the coordinates (L, Δy2, Δz2) of the clamping center point on the right clamping surface, where L is the distance between the left clamping surface and the right clamping surface, and the right clamping surface is the contact surface of the first clamping component 24 and the second clamping component 25 in the clamping mechanism 2 at the right end of the current transformer body 1 along the axis.

[0045] Specifically, the control unit 7 determines the coordinates (0, Δy1, Δz1) of the left clamping surface through the following steps:

[0046] S1. Obtain the compression length of the compression springs 4 on both sides of the first clamping component 24 on the left clamping surface, and calculate the difference ΔA1. Based on the symmetrical structure, the deviation displacement of the clamping center of the first clamping component 24 on the left clamping surface in the y-axis direction is half of the difference in compression length of the compression springs 4 on both sides, that is, Δy1=(1 / 2)·ΔA1.

[0047] S2. Obtain the compression length of the compression springs 4 on both sides of the second clamping component 25 on the left clamping surface, and calculate the difference ΔB1. Based on the symmetrical structure, the offset displacement of the clamping center of the second clamping component 25 on the left clamping surface in the z-axis direction is half of the difference in compression length of the compression springs 4 on both sides, i.e. Δz1=(1 / 2)·ΔB1.

[0048] S3. Determine the coordinates (0, Δy1, Δz1) of the clamping center point on the left clamping surface based on the deviation displacements Δy1 and Δz1.

[0049] Specifically, the control unit 7 determines the coordinates (L, Δy2, Δz2) of the right clamping surface through the following steps:

[0050] S4. Obtain the compression length of the compression springs 4 on both sides of the first clamping component 24 at the right clamping surface, and calculate the difference ΔA2. Similarly, calculate Δy2=(1 / 2)·ΔA2 based on the symmetrical structure.

[0051] S5. Obtain the compression length difference ΔB2 between the compression springs 4 on both sides of the second clamping component 25 at the right clamping surface, and calculate Δz2=(1 / 2)·ΔB2 based on the symmetrical structure.

[0052] S6. Determine the coordinates (L, Δy2, Δz2) of the clamping center point on the right clamping surface based on the deviation displacements Δy2 and Δz2.

[0053] Reference Figure 1 and Figure 6 The control unit 7 is also configured to calculate the actual current value of the busbar or busbar under test based on the coordinates of the clamping center point (0, Δy1, Δz1) on the left clamping surface and the coordinates of the clamping center point (L, Δy2, Δz2) on the right clamping surface using a current compensation algorithm. The current compensation algorithm includes the following steps:

[0054] S7. Based on the spatial coordinate differences Δx=L, Δy=Δy2-Δy1 and Δz=Δz2-Δz1 between the clamping center point on the left clamping surface and the clamping center point on the right clamping surface, calculate the equivalent tilt angle parameters of the busbar or busbar to be measured.

[0055] S8, based on the equivalent tilt angle parameter and the real-time detection current value I 检 Through compensation formula I 实 =I 检 ·N·[1+α·((Δy)²+(Δz)²) / L²] calculates the actual current value I of the busbar or busbar under test. 实 Where N is the turns ratio of the metering low-voltage current transformer, α is the compensation coefficient determined through calibration, and L is the distance between the left and right clamping surfaces.

[0056] It is worth noting that the compensation coefficient α is a comprehensive characteristic parameter determined by the physical structure, electromagnetic parameters, and operating conditions of the low-voltage current transformer itself. Its value depends on calibration using multiple or even a large amount of experimental data under controllable conditions, thereby ensuring the effectiveness and accuracy of the compensation formula in practical applications.

[0057] In operation, intelligent management is achieved through the cooperation of control unit 7 and thin-film piezoelectric sensor 5. By processing the data from thin-film piezoelectric sensor 5, control unit 7 can calculate the compression state of the corresponding spring 4, thereby reflecting the position state of clamping mechanism 2. This provides support for the clamping posture positioning of the busbar or busbar under test and error compensation for current detection. The automated processing of control unit 7 reduces human intervention and improves the reliability of the system. Control unit 7 can intelligently correct the current measurement results according to the actual spatial position of the busbar or busbar under test, thereby reducing or eliminating measurement errors caused by non-centered wiring. This allows the metering low-voltage current transformer to output high-precision measurement results even under non-ideal installation conditions, broadening the application range and practicality of the product.

[0058] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A portable metering low-voltage current transformer, comprising a transformer body (1) and clamping mechanisms (2) disposed at the left and right axial ends of the transformer body (1), characterized in that: The clamping mechanism (2) includes a housing (21) and a square frame (22) provided in the housing (21). The inner walls of the square frame (22) form a square through hole (23) that penetrates the housing (21). The side length of the square through hole (23) is greater than the diameter of the through hole of the transformer body (1). The square through hole (23) is provided with a first clamping plate (241) and a second clamping plate (242) arranged opposite to each other, as well as a third clamping plate (251) and a fourth clamping plate (252) arranged opposite to each other. The first clamping plate (241), the second clamping plate (242), the third clamping plate (251) and the fourth clamping plate (252) are arranged in a "well" shape and enclose a clamping space (26). The first clamping plate (241), the second clamping plate (242), the third clamping plate (251) and the fourth clamping plate (252) are respectively provided with an adjustment mechanism (3) on the side away from the clamping space (26). The adjustment mechanism (3) includes an adjustment screw (31) and an operating lever (32). One end of the adjustment screw (31) is rotatably connected to the side of the corresponding clamping plate away from the clamping space (26). The other end of the adjustment screw (31) is connected to the operating lever (32). The square frame (22) is provided with a threaded hole (221) adapted to the adjustment screw (31). The mounting housing (21) is provided with a through hole (2111) for the operating lever (32) to pass through. A limiting end plate (33) is fixedly connected between the adjusting screw (31) and the operating lever (32). A compression spring (4) is sleeved on the outside of the operating lever (32). One end of the compression spring (4) abuts against the limiting end plate (33), and the other end abuts against the inner wall of the housing (21). A thin film piezoelectric sensor (5) is provided on the inner wall of the housing (21). The end of the compression spring (4) away from the limiting end plate (33) presses against the sensing end of the thin film piezoelectric sensor (5). The operating lever (32) includes a fixed lever (321) and a hinge lever (322) arranged coaxially. The fixed lever (321) is fixed coaxially with the adjusting screw (31), and one end of the hinge lever (322) is hinged to the end of the fixed lever (321) away from the adjusting screw (31) by a hinge (323).

2. The portable metering low-voltage current transformer according to claim 1, characterized in that: The first clamping plate (241) and the second clamping plate (242) constitute the first clamping assembly (24), and the third clamping plate (251) and the fourth clamping plate (252) constitute the second clamping assembly (25). The first clamping assembly (24) and the second clamping assembly (25) are misaligned and one side of them is attached to each other. The first clamping component (24) is slidably connected to one pair of opposite sidewalls of the square frame (22) along the length direction of the square frame (22), and the second clamping component (25) is slidably connected to another pair of opposite sidewalls of the square frame (22) along the width direction of the square frame (22).

3. A convenient metering low-voltage current transformer according to claim 1, characterized in that: The hinge rod (322) has a rotating part (3221) fixed at one end away from the fixed rod (321), and a guide cone surface (3222) is provided at the other end of the hinge rod (322) near the fixed rod (321).

4. A convenient metering low-voltage current transformer according to claim 1, characterized in that: It also includes a control unit (7), which is signal-connected to each thin-film piezoelectric sensor (5), and the control unit (7) is configured to calculate the compression length of the corresponding compression spring (4) based on the measurement data of the thin-film piezoelectric sensor (5).

5. A convenient metering low-voltage current transformer according to claim 4, characterized in that: The control unit (7) is configured to establish a spatial coordinate system, wherein the mating surface of the first clamping component (24) and the second clamping component (25) in the clamping mechanism (2) at the left end of the axial direction of the transformer body (1) is the left clamping surface, the left clamping surface is the yz plane, and the direction of the center line of the through hole is the x-axis. The control unit (7) is configured to determine the coordinates (0, Δy1, Δz1) of the clamping center point on the left clamping surface and the coordinates (L, Δy2, Δz2) of the clamping center point on the right clamping surface, where L is the distance between the left clamping surface and the right clamping surface, and the right clamping surface is the contact surface of the first clamping component (24) and the second clamping component (25) in the clamping mechanism (2) at the right end of the axial direction of the transformer body (1).

6. A convenient metering low-voltage current transformer according to claim 5, characterized in that: The control unit (7) is also configured to calculate the actual current value of the busbar or busbar under test based on the coordinates of the clamping center point (0, Δy1, Δz1) on the left clamping surface and the coordinates of the clamping center point (L, Δy2, Δz2) on the right clamping surface using a current compensation algorithm.

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