A split-type current transformer

Abstract

The present invention discloses an open-and-close current transformer, which specifically relates to the technical field of transformers. The invention comprises a shell having a giveway groove formed on the shell, and a first iron core, which is located in the shell and has a slot corresponding to the giveway groove formed on the first iron core. An induction coil is wound on the first iron core, and multiple outer surfaces of the first iron core are provided with a fixed shielding layer, which is located between the first iron core and the shell. The sliding part comprises a sliding block, which is sleeved on the shell and slidably connected to the shell. A second iron core capable of cooperating with the connecting slot is provided in the sliding block, and a movable shielding layer is wrapped on the sliding block. The movable shielding layer can be staggered and docked with the fixed shielding layer as the sliding block moves, thereby forming a magnetic leakage prevention structure with no dead angles. The present application can reduce the matching gap between the iron cores and improve the ability to resist magnetic field interference.

Description

Technical Field

[0001] The present invention relates to the technical field of mutual inductors, and more particularly to a split-type current mutual inductor. Background Art

[0002] As a key sensing device in the power system, the current transformer has a core structure composed of a high-precision iron core, a primary conductive winding, a secondary inductive winding, a high-conductivity terminal block and a composite insulation support system. The device is based on Faraday's law of electromagnetic induction and uses the magnetic coupling effect to achieve precise conversion of high-load current on the primary side to standard measurement current on the secondary side, providing isolated and amplified electrical quantity signals for secondary equipment such as relay protection and metering monitoring. Among them, the split-type current transformer is a new type of detachable sensing unit with a modular magnetic circuit design, breaking through the physical limitations of traditional transformers on the installation cross-section, supporting hot-swappable operations under power, and realizing power-free transformation of the busbar system.

[0003] There are mainly two structural forms of existing open-and-close current transformers: one is an open-and-close shell design based on a hinge mechanism, and the other is a segmented modular structure assembled with bolts. Due to the inherent geometric characteristics of the annular magnetic circuit, both of the above methods require double-section magnetic coupling docking during the core docking process. This discontinuous magnetic circuit structure leads to the following inherent defects: the integrity of the magnetic circuit is destroyed, and the air gap formed at the core joint significantly increases the magnetic resistance, resulting in increased main magnetic flux leakage. The double-section docking process introduces cumulative measurement tolerances. When the primary current is in a transient process, the time-varying magnetic field excites eddy current loss in the air gap, further aggravating the phase error and affecting the accuracy of the measurement results. The traditional shielding scheme uses attached high-magnetic permeability materials to construct a magnetic shielding layer, but there are physical breakpoints at the movable joints, and a nonlinear magnetic resistance section is formed in the breakpoint area, causing the external stray magnetic field to be directly coupled to the secondary winding through the air gap, seriously affecting the accuracy of the current measurement results. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a split current transformer to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a split-type current transformer, comprising a housing, the housing having a recess, and further comprising:

[0006] The fixed portion includes a first iron core, the first iron core is located in the housing, a slot corresponding to the clearance slot is formed on the first iron core, an induction coil is wound around the first iron core, and multiple outer surfaces of the first iron core are provided with a fixed shielding layer, the fixed shielding layer is located between the first iron core and the housing;

[0007] The sliding part includes a sliding block, which is sleeved on the shell and slidably connected to the shell. A second iron core that can cooperate with the connecting groove is provided in the sliding block. The sliding block is wrapped with a movable shielding layer. The movable shielding layer can move with the sliding block and interlock with the fixed shielding layer to form a magnetic leakage prevention structure with no dead angles.

[0008] Preferably, two connection terminals are provided at the bottom of the shell, and the two connection terminals are electrically connected to the free ends of the corresponding induction coils respectively.

[0009] Preferably, the fixed shielding layer consists of an upper shielding plate, a lower shielding plate, an inner shielding plate and an outer shielding plate, the upper shielding plate is located at the top of the first iron core, the lower shielding plate is located at the bottom of the first iron core, the inner shielding plate is located on the inner arc surface of the first iron core, and the outer shielding plate is located on the outer arc surface of the first iron core.

[0010] Preferably, a sliding groove is provided on the sliding block, and the sliding block is slidably connected to the housing through the sliding groove.

[0011] Preferably, the circumference of the first iron core is greater than the circumference of the shell, and the opening of the first iron core is located in the clearance groove.

[0012] Preferably, a receiving groove connected to the give way groove is provided in the sliding block, a plurality of guide grooves are provided on the side wall of the receiving groove, a plurality of guide blocks corresponding to the guide grooves are provided on the second iron core, and the guide blocks are slidably connected to the corresponding guide grooves.

[0013] Preferably, a circular groove connected to the accommodating groove is opened on the top of the sliding block, and a pull rod is slidably connected in the circular groove. The upper end of the pull rod passes through the movable shielding layer and is provided with a handle. The lower end of the pull rod is connected to the second iron core, and the pull rod is provided with a spring located between the side wall of the accommodating groove and the second iron core.

[0014] Preferably, the shape of the slot is fan-shaped, and the circumference of the slot on the side close to the center of the first iron core is smaller than the circumference of the slot on the side away from the center of the first iron core.

[0015] Preferably, a limit plate is fixedly connected to the outer surface of the shell, and the limit plate can contact the side wall of the sliding block.

[0016] Preferably, the upper end of the second core is fixedly connected to an adjustment block, the adjustment block is provided with an inverted T-shaped connection groove, the lower end of the pull rod is fixedly connected to a connection plate, and the connection plate is slidably connected to the connection groove.

[0017] Technical effects and advantages of the present invention:

[0018] 1. The present invention accurately limits the matching position of the second iron core and the first iron core through the matching arrangement of the shell, the first iron core, the yield groove, the card slot, the sliding block, the pull rod, and the second iron core, and preliminarily limits the matching position of the sliding part by the limiting plate. On this basis, in the process of the pull rod driving the second iron core to move downward, the downward pressure position of the second iron core is corrected through the matching of the adjustment block, the connecting groove, and the connecting plate. Furthermore, the spring provides continuous matching pressure. Under the common limitation of the inclined surface of the card slot, the matching position of the second iron core and the first iron core is limited as much as possible, thereby reducing the air gap after matching and improving the accuracy of the detection results.

[0019] 2. The present invention cooperates with the sliding part, the upper shielding plate, the lower shielding plate, the inner shielding plate, the outer shielding plate and the movable shielding layer. When the first iron core and the second iron core are matched, the sliding block moves to the clearance groove of the shell. The sliding block then drives the movable shielding layer to move to the clearance groove of the shell. The movable shielding layer and the fixed shielding layer are staggered and docked, completely wrapping the first iron core and the second iron core to form a magnetic leakage prevention structure with no dead angle. While realizing opening and closing, the moving characteristics of the sliding part are used to make the movable shielding layer move accordingly, avoiding the occurrence of shielding breakpoints and minimizing the influence of the external magnetic field on the detection results of the current transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0021] Figure 2 It is a full-section front view of the present invention.

[0022] Figure 3 This is an exploded view of the first iron core and the fixed shielding layer of the present invention.

[0023] Figure 4 Schematic diagram of the structure of the sliding block of the present invention.

[0024] Figure 5 It is a schematic diagram of the structure inside the sliding block of the present invention.

[0025] Figure 6 It is a structural schematic diagram of the pull rod, connecting plate, connecting groove and adjusting block of the present invention.

[0026] Figure 7 It is a structural schematic diagram of the pull rod, connecting plate and connecting groove of the present invention.

[0027] The accompanying drawings are marked as follows: 1. Shell; 2. Giving way groove; 3. Fixing part; 301. First iron core; 302. Card slot; 303. Fixed shielding layer; 3031. Upper shielding plate; 3032. Lower shielding plate; 3033. Inner shielding plate; 3034. Outer shielding plate; 304. Terminal; 4. Sliding part; 401. Sliding block; 402. Second iron core; 403. Movable shielding layer; 404. Sliding groove; 405. Accommodating groove; 406. Guide groove; 407. Guide block; 408. Circular groove; 409. Pull rod; 410. Handle; 411. Spring; 412. Limiting plate; 413. Adjusting block; 414. Connecting groove; 415. Connecting plate. DETAILED DESCRIPTION

[0028] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] Example 1

[0030] There are two main structural forms of existing split-type current transformers: one is a split-shell design based on a hinge mechanism, and the other is a segmented modular structure assembled with bolts. Due to the inherent geometric characteristics of the annular magnetic circuit, both of the above methods require double-section magnetic coupling docking during the core alignment process. This discontinuous magnetic circuit integrity is destroyed, and the air gap formed at the core joint significantly increases the magnetic resistance, resulting in increased main magnetic flux leakage. The double-section docking process introduces cumulative measurement tolerances. When the primary current is in a transient process, the time-varying magnetic field excites eddy current loss in the air gap, further aggravating the phase error and affecting the accuracy of the measurement results.

[0031] To solve the above technical problems, please refer to Figures 1 to 7 As shown, the first embodiment of the present invention provides an open-close current transformer, including a shell 1, a recess 2 is provided on the shell 1, and a fixed part 3 and a sliding part 4. The fixed part 3 includes a first iron core 301, the first iron core 301 is located in the shell 1, and a slot 302 corresponding to the recess 2 is provided on the first iron core 301. An induction coil is wound on the first iron core 301, and multiple outer surfaces of the first iron core 301 are provided with a fixed shielding layer 303, and the fixed shielding layer 303 is located between the first iron core 301 and the shell 1. The sliding part 4 includes a sliding block 401, which is sleeved on the shell 1 and slidably connected to the shell 1. A second iron core 402 that can cooperate with the connecting slot 414 is provided in the sliding block 401. Two connecting terminals 304 are provided at the bottom of the shell 1, and the two connecting terminals 304 are respectively electrically connected to the free ends of the corresponding induction coils.

[0032] The sliding block 401 is provided with a sliding groove 404 , which is arc-shaped. The sliding block 401 is slidably connected to the housing 1 via the sliding groove 404 , and the sliding block 401 can move along the length direction of the housing 1 .

[0033] The circumference of the first iron core 301 is greater than that of the housing 1 , and the opening of the first iron core 301 is located in the clearance slot 2 .

[0034] A receiving groove 405 connected to the give way groove 2 is provided in the sliding block 401, and the lower end of the receiving groove 405 is connected to the sliding groove 404. A plurality of guide grooves 406 are provided on the side wall of the receiving groove 405, and a plurality of guide blocks 407 corresponding to the guide grooves 406 are provided on the second iron core 402. The guide blocks 407 are slidably connected to the corresponding guide grooves 406.

[0035] A circular groove 408 connected to the accommodating groove 405 is provided on the top of the sliding block 401, and a pull rod 409 is slidably connected in the circular groove 408. The upper end of the pull rod 409 passes through the movable shielding layer 403 and is provided with a handle 410. The lower end of the pull rod 409 is connected to the second iron core 402, and a spring 411 is mounted on the pull rod 409 and is located between the side wall of the accommodating groove 405 and the second iron core 402.

[0036] The shape of the slot 302 is fan-shaped. The circumference of the slot 302 close to the center of the first core 301 is smaller than the circumference of the slot 302 away from the center of the first core 301. The left and right end surfaces of the slot 302 are inclined.

[0037] A limiting plate 412 is fixedly connected to the outer surface of the housing 1 , and the limiting plate 412 can contact the side wall of the sliding block 401 .

[0038] An adjustment block 413 is fixedly connected to the upper end of the second iron core 402, and an inverted T-shaped connecting groove 414 is provided on the adjustment block 413. A connecting plate 415 is fixedly connected to the lower end of the pull rod 409. The connecting plate 415 is slidably connected to the connecting groove 414. The pull rod 409 can drive the adjustment block 413 to move up and down, and the adjustment block 413 can move in the horizontal direction relative to the pull rod 409.

[0039] In actual use, in order to avoid secondary open circuit, the two terminal blocks 304 are connected to the positive and negative poles of the ammeter respectively. When it is necessary to detect the current of the circuit in the power system, the sliding part 4 needs to be opened to separate the first iron core 301 and the second iron core 402, so that the clearance slot 2 of the shell 1 is in an open state, and the measured wire passes through the clearance slot 2 on the shell 1 and enters the shell 1.

[0040] Pull the handle 410 to move upward and compress the spring 411. The handle 410 drives the connecting plate 415 to move upward through the pull rod 409. The connecting plate 415 drives the adjustment block 413 to move upward through the connecting groove 414. The adjustment block 413 drives the second iron core 402 to move upward. In the process of the second iron core 402 moving upward, it drives multiple guide blocks 407 to move in the corresponding guide groove 406. When the handle 410 drives the pull rod 409 to move upward to the extreme position, the spring 411 is in a compressed state, and the second iron core 402 moves out of the slot 302. The second iron core 402 is now separated from the first iron core 301, and the second iron core 402 moves upward to the accommodating slot 405. At this time, there are no other parts in the sliding slot 404, and the handle 410 is pushed to the right. Swing, and with the cooperation of the sliding groove 404 and the shell 1, the entire sliding part 4 moves to the right along the trajectory of the shell 1. As the sliding part 4 moves to the right, the makeshift groove 2 opened on the shell 1 is gradually exposed. When the effective passing area of ​​the makeshift groove 2 is large enough, release the handle 410, and under the reset action of the spring 411, the pull rod 409 moves downward. The pull rod 409 drives the adjustment block 413 to move downward through the connecting plate 415 and the connecting groove 414. The adjustment block 413 drives the second iron core 402 to move downward, and the second iron core 402 drives the guide block 407 to move downward in the guide groove 406. When the lower end of the second iron core 402 contacts the surface of the shell 1, the position of the sliding part 4 is limited. At this time, move the shell 1 so that the measured wire is located in the shell 1.

[0041] Then close the housing 1, pull the handle 410 to move upward, release the limit, push the handle 410 to move to the left, the handle 410 drives the entire sliding part 4 to move to the left, the sliding block 401 drives the second iron core 402 to move to the left, and when the left end of the sliding block 401 contacts the limit plate 412, push the handle 410 to move downward, and the pull rod 409 moves downward under the reset force of the handle 410 and the spring 411. The pull rod 409 drives the adjustment block 413 and the second iron core 402 to move downward through the connecting plate 415 and the connecting groove 414. Since the two end faces of the second iron core 402 and the two end faces of the first iron core 301 are inclined surfaces, their inclined state is as shown in FIG. Figure 2As shown, when a slight deviation occurs when the second core 402 is matched with the slot 302, one of the inclined surfaces of the second core 402 first contacts the slot 302. As the second core 402 moves downward, the second core 402 gradually matches the slot 302 of the first core 301. When the second core 402 deflects to one side relative to the slot 302, the second core 402 and the adjustment block 413 move relative to the connecting plate 415 and the connecting slot 414 under the push of the inclined surface. Under the joint action of the inclined surfaces of the two slots 302, the second core 402 is matched with the slot 302 of the first core 301. At the same time, under the continuous pressure of the spring 411, the second core 40 2 can fit the end face of the first core 301 as closely as possible, reducing the air gap after fitting, and due to the inclined state of the inclined surface, the downward movement position of the second core 402 is limited, reducing the air gap after fitting, and further, the fitting position of the second core 402 and the first core 301 is preliminarily limited by the limiting plate 412, and the fitting is corrected by the adjusting block 413 in the process of the pull rod 409 driving the second core 402 to move downward, and the spring 411 provides continuous fitting pressure, and the fitting position of the second core 402 and the first core 301 is limited under the common limitation of the inclined surface of the slot 302, reducing the air gap after fitting and improving the accuracy of the detection results.

[0042] Example 2

[0043] Traditional shielding solutions use attached high-permeability magnetic materials to construct a magnetic shielding layer. However, since the core joints need to be moved, two core shielding layers need to be attached. In order to meet the end-face connection of the cores, a clearance setting is required to avoid motion interference. However, the clearance setting creates a physical breakpoint at the joint, forming a nonlinear magnetic resistance cross-section in the breakpoint area, causing the external stray magnetic field to be directly coupled to the secondary winding through the air gap, seriously affecting the accuracy of the current measurement results.

[0044] See also Figures 1 to 7 As shown, the sliding block 401 is wrapped with a movable shielding layer 403 , which can move with the sliding block 401 and interlock with the fixed shielding layer 303 to form a magnetic leakage prevention structure without dead angles.

[0045] The fixed shielding layer 303 is composed of an upper shielding plate 3031, a lower shielding plate 3032, an inner shielding plate 3033 and an outer shielding plate 3034. The upper shielding plate 3031 is located at the top of the first iron core 301, the lower shielding plate 3032 is located at the bottom of the first iron core 301, the inner shielding plate 3033 is located on the inner arc surface of the first iron core 301, and the outer shielding plate 3034 is located on the outer arc surface of the first iron core 301.

[0046] On the basis of the above embodiment, in order to shield the iron core to prevent magnetic leakage, a plurality of fixed shielding layers 303 are provided between the first iron core 301 and the shell 1 to wrap the first iron core 301, but the part of the first iron core 301 located in the give way groove 2 cannot be effectively wrapped. In order to compensate for this defect, the surface of the sliding block 401 is wrapped with a movable shielding layer 403, and the movable shielding layer 403 can move with the sliding block 401. When it is necessary to open the shell 1 and put the measured wire into the shell 1, the first iron core 301 and the second iron core 402 are disconnected. When the first iron core 301 and the second iron core 402 are matched, the sliding block 401 moves to the give way groove 2 of the shell 1. The sliding block 401 drives the movable shielding layer 403 to move to the give way groove 2 of the shell 1. At this time, Figure 2 As shown, the movable shielding layer 403 and the fixed shielding layer 303 are staggered and docked, completely wrapping the first iron core 301 and the second iron core 402 to form a magnetic leakage prevention structure with no dead angles. While satisfying the opening and closing of the shell 1, the moving characteristics of the sliding part 4 are utilized to make the movable shielding layer 403 move accordingly. The movable shielding layer 403 can move with the sliding block 401 and staggered and dock with the fixed shielding layer 303 to form a magnetic leakage prevention structure with no dead angles, avoid the occurrence of shielding breakpoints, and minimize the influence of the external magnetic field on the detection results.

[0047] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A split-type current transformer, comprising a housing, wherein a recess is provided on the housing, wherein: Also includes: The fixed portion includes a first iron core, the first iron core is located in the housing, a slot corresponding to the clearance slot is formed on the first iron core, an induction coil is wound around the first iron core, and multiple outer surfaces of the first iron core are provided with a fixed shielding layer, the fixed shielding layer is located between the first iron core and the housing; The sliding part includes a sliding block, which is sleeved on the shell and slidably connected to the shell. A second iron core that can cooperate with the slot is provided in the sliding block. The sliding block is wrapped with a movable shielding layer. The movable shielding layer can move with the sliding block and interlock with the fixed shielding layer to form a magnetic leakage prevention structure with no dead angles.

2. The split-type current transformer according to claim 1, characterized in that: Two connection terminals are provided at the bottom of the shell, and the two connection terminals are electrically connected to the free ends of the corresponding induction coils respectively.

3. The split-type current transformer according to claim 2, characterized in that: The fixed shielding layer consists of an upper shielding plate, a lower shielding plate, an inner shielding plate and an outer shielding plate. The upper shielding plate is located at the top of the first iron core, the lower shielding plate is located at the bottom of the first iron core, the inner shielding plate is located on the inner arc surface of the first iron core, and the outer shielding plate is located on the outer arc surface of the first iron core.

4. The split-type current transformer according to claim 3, characterized in that: The sliding block is provided with a sliding groove, and the sliding block is slidably connected to the housing through the sliding groove.

5. The split-type current transformer according to claim 4, characterized in that: The circumference of the first iron core is greater than the circumference of the shell, and the opening of the first iron core is located in the clearance groove.

6. The split-type current transformer according to claim 5, characterized in that: The sliding block is provided with a receiving groove connected to the giving way groove, and the side wall of the receiving groove is provided with multiple guide grooves. The second iron core is provided with multiple guide blocks corresponding to the guide grooves, and the guide blocks are slidably connected to the corresponding guide grooves.

7. The split-type current transformer according to claim 6, characterized in that: A circular groove connected to the accommodating groove is provided on the top of the sliding block, and a pull rod is slidably connected in the circular groove. The upper end of the pull rod passes through the movable shielding layer and is provided with a handle. The lower end of the pull rod is connected to the second iron core, and the pull rod is provided with a spring located between the side wall of the accommodating groove and the second iron core.

8. The split-type current transformer according to claim 7, characterized in that: The shape of the slot is fan-shaped, and the circumference of the slot on the side close to the center of the first iron core is smaller than the circumference of the slot on the side away from the center of the first iron core.

9. The split-type current transformer according to claim 8, characterized in that: The outer surface of the shell is fixedly connected to a limit plate, and the limit plate can contact the side wall of the sliding block.

10. The split-type current transformer according to claim 9, characterized in that: The upper end of the second core is fixedly connected with an adjustment block, and an inverted T-shaped connection groove is opened on the adjustment block. The lower end of the pull rod is fixedly connected with a connection plate, and the connection plate is slidably connected to the connection groove.

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