Open-close type current transformer

Abstract

The invention discloses an open-close type current transformer, and particularly relates to the technical field of mutual inductors, the open-close type current transformer comprises a shell, an avoiding groove is formed in the shell, the open-close type current transformer further comprises a first iron core, the first iron core is located in the shell, a clamping groove corresponding to the avoiding groove is formed in the first iron core, an induction coil is wound on the first iron core, and the first iron core is located in the shell. A plurality of outer surfaces of the first iron core are all provided with fixed shielding layers, the fixed shielding layers are located between the first iron core and the shell, the sliding part comprises a sliding block, the sliding block is arranged on the shell in a sleeving mode and connected with the shell in a sliding mode, and a second iron core capable of being matched with the connecting groove is arranged in the sliding block. The sliding block is wrapped with a movable shielding layer, and the movable shielding layer can move along with the sliding block to be in butt joint with the fixed shielding layer in a staggered mode to form a dead-corner-free magnetic leakage prevention structure. According to the invention, the fit clearance between the iron cores can be reduced, and the magnetic field interference resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of current transformers, and more specifically, to an opening and closing type current transformer. Background Art

[0002] As a key sensing device in the power system, the core structure of a current transformer consists of a high-precision iron core, a primary conductive winding, a secondary induction winding, highly conductive terminal blocks, and a composite insulation support system. Based on Faraday's law of electromagnetic induction, this device realizes the accurate conversion of high-load current on the primary side to a standard measurement current on the secondary side through the magnetic coupling effect, providing an electrically isolated and amplified electrical quantity signal for secondary devices such as relay protection and metering monitoring. Among them, the opening and closing type current transformer, as a new type of separable sensing unit, adopts a modular magnetic circuit design, breaks through the physical limitations of traditional transformers on the installation cross-section, supports hot plugging and unplugging operations while energized, and realizes the power-off-free transformation of the bus system.

[0003] There are mainly two structural forms of existing opening and closing type current transformers: one is the shell opening and closing type 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 toroidal magnetic circuit, both of the above methods need to achieve double-section magnetic coupling docking during the iron core docking process. This non-continuous magnetic circuit structure leads to the following inherent defects: the integrity of the magnetic circuit is damaged, the air gap formed at the iron core joint significantly increases the magnetic resistance, resulting in increased leakage of the main magnetic flux, the double-section docking process introduces cumulative measurement tolerances, and when the primary current is in a transient process, the time-varying magnetic field excites eddy current losses in the air gap, further exacerbating the phase error and affecting the accuracy of the measurement results. The traditional shielding scheme uses attached high-permeability materials to construct a magnetic shielding layer, but there is a physical break at the movable joint, and the break area forms a non-linear magnetic resistance cross-section, resulting in direct coupling of external stray magnetic fields 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 an opening and closing type current transformer to solve the problems raised in the above background art.

[0005] To achieve the above object, the present invention provides the following technical solution: An opening and closing type current transformer, including a housing, a relief groove is opened on the housing, and further includes: A fixing part, which includes a first iron core, the first iron core is located inside the housing, a clamping groove corresponding to the relief groove is opened on the first iron core, an induction coil is wound around the first iron core, and fixed shielding layers are provided on multiple outer surfaces of the first iron core, and the fixed shielding layers are 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. The sliding block is provided with a second iron core that can cooperate with the connecting groove. 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 angle.

[0006] Preferably, two wiring terminals are provided at the bottom of the shell, and the two wiring terminals are electrically connected to the free ends of the corresponding induction coils respectively.

[0007] 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.

[0008] Preferably, a sliding groove is provided on the sliding block, and the sliding block is slidably connected to the housing via the sliding groove.

[0009] 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 give way groove.

[0010] Preferably, a receiving groove connected to the giving 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.

[0011] 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, and the lower end of the pull rod is connected to the second iron core. The pull rod is provided with a spring located between the side wall of the accommodating groove and the second iron core.

[0012] Preferably, the shape of the slot is fan-shaped, and the circumference of the slot on a side close to the center of the first core is smaller than the circumference of the slot on a side away from the center of the first core.

[0013] 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.

[0014] Preferably, an adjustment block is fixedly connected to the upper end of the second core, an inverted T-shaped connection groove is provided on the adjustment block, and a connection plate is fixedly connected to the lower end of the pull rod, and the connection plate is slidably connected to the connection groove.

[0015] Technical effects and advantages of the present invention: 1. Through the cooperative setting of the housing, the first iron core, the relief groove, the card slot, the sliding block, the pull rod, and the second iron core, the cooperative position between the second iron core and the first iron core is accurately defined. The limiting plate preliminarily defines the cooperative position of the sliding part. On this basis, during the process of the pull rod driving the second iron core to move downward, through the cooperation of the adjustment block, the connection groove, and the connection plate, the downward pressure position of the second iron core is corrected. Further, the spring provides continuous cooperative pressure, and under the common limitation of the inclined surface of the card slot, the cooperative position between the second iron core and the first iron core is limited as much as possible, reducing the air gap after cooperation and improving the accuracy of the detection result.

[0016] 2. Through the cooperative setting of the sliding part, the upper shielding plate, the lower shielding plate, the inner shielding plate, the outer shielding plate, and the moving shielding layer, when the first iron core and the second iron core complete the cooperation, the sliding block moves to the relief groove of the housing. At this time, the sliding block drives the moving shielding layer to move to the relief groove of the housing, and the moving 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 leak - proof magnetic structure without dead angles. While realizing the opening and closing, by using the moving characteristics of the sliding part, the moving shielding layer moves correspondingly to avoid the occurrence of shielding breakpoints, and as much as possible reduces the influence of the external magnetic field on the detection result of the current transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 It is a full - section front view of the present invention.

[0019] Figure 3 It is an exploded view of the first iron core and the fixed shielding layer of the present invention.

[0020] Figure 4 It is a schematic diagram of the structure of the sliding block of the present invention.

[0021] Figure 5 It is a schematic diagram of the structure inside the sliding block of the present invention.

[0022] Figure 6 It is a schematic diagram of the structure of the pull rod, the connection plate, the connection groove, and the adjustment block of the present invention.

[0023] Figure 7 It is a schematic diagram of the structure of the pull rod, the connection plate, and the connection groove of the present invention.

[0024] The reference numerals are as follows: 1, housing; 2, relief groove; 3, fixing part; 301, first iron core; 302, clamping groove; 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, slider; 402, second iron core; 403, moving shielding layer; 404, sliding groove; 405, receiving groove; 406, guiding groove; 407, guiding block; 408, circular groove; 409, pull rod; 410, handle; 411, spring; 412, limiting plate; 413, adjusting block; 414, connecting groove; 415, connecting plate. Detailed implementation manners

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] Embodiment 1 There are mainly two structural forms in the existing split-type current transformers: one is the housing split-type design based on the hinge mechanism, and the other is the segmented modular structure assembled by bolts. Due to the inherent geometric characteristics of the toroidal magnetic circuit, the above two methods both need to achieve double-section magnetic coupling docking during the iron core alignment process. This destruction of the integrity of the discontinuous magnetic circuit significantly increases the magnetic resistance due to the air gap formed at the iron core joint, resulting in increased leakage of the main magnetic flux. The double-section docking process introduces cumulative measurement tolerances. When the primary current is in the transient process, the time-varying magnetic field excites eddy current losses in the air gap, further exacerbating the phase error and affecting the accuracy of the measurement result.

[0027] To solve the above technical problems, please refer to Figures 1 to 7 As shown, the first embodiment of the present invention provides a split-type current transformer, including a housing 1, a relief groove 2 is provided on the housing 1, and further includes a fixing part 3 and a sliding part 4. The fixing part 3 includes a first iron core 301, the first iron core 301 is located inside the housing 1, a clamping groove 302 corresponding to the relief groove 2 is provided on the first iron core 301, an induction coil is wound on the first iron core 301, fixed shielding layers 303 are provided on multiple outer surfaces of the first iron core 301, the fixed shielding layer 303 is located between the first iron core 301 and the housing 1, the sliding part 4 includes a slider 401, the slider 401 is sleeved on the housing 1 and is slidably connected to the housing 1, a second iron core 402 capable of cooperating with the connecting groove 414 is provided inside the slider 401, two terminals 304 are provided at the bottom of the housing 1, and the two terminals 304 are respectively electrically connected to the free ends of the corresponding induction coils.

[0028] The sliding block 401 is provided with a sliding groove 404, the shape of the sliding groove 404 is arc-shaped, the sliding block 401 is slidably connected to the housing 1 through the sliding groove 404, and the sliding block 401 can move along the length direction of the housing 1.

[0029] The circumference of the first iron core 301 is greater than the circumference of the housing 1, and the opening of the first iron core 301 is located in the relief groove 2.

[0030] The sliding block 401 is provided with a receiving groove 405 communicating with the relief groove 2, the lower end of the receiving groove 405 communicates with the sliding groove 404, and a plurality of guiding grooves 406 are provided on the side wall of the receiving groove 405. A plurality of guiding blocks 407 corresponding to the guiding grooves 406 are provided on the second iron core 402, and the guiding blocks 407 are slidably connected to the corresponding guiding grooves 406.

[0031] A circular groove 408 communicating with the receiving groove 405 is provided at the top of the sliding block 401. A pull rod 409 is slidably connected in the circular groove 408. The upper end of the pull rod 409 penetrates through the moving 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 sleeved on the pull rod 409 and located between the side wall of the receiving groove 405 and the second iron core 402.

[0032] The shape of the clamping groove 302 is fan-shaped. The circumference of the clamping groove 302 on the side close to the center of the first iron core 301 is smaller than the circumference on the side far from the center of the first iron core 301, and the two end faces on the left and right of the clamping groove 302 are inclined.

[0033] 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.

[0034] The upper end of the second iron core 402 is fixedly connected with an adjusting block 413. An inverted T-shaped connecting groove 414 is provided on the adjusting block 413. The lower end of the pull rod 409 is fixedly connected with a connecting plate 415. The connecting plate 415 is slidably connected to the connecting groove 414. The pull rod 409 can drive the adjusting block 413 to move up and down, and at the same time, the adjusting block 413 can move horizontally relative to the pull rod 409.

[0035] In actual use, in order to avoid secondary open circuit, the two wiring terminals 304 are respectively connected to the positive and negative poles of the ammeter. When it is necessary to detect the current of the circuit in the power system, it is necessary to open the sliding part 4 to separate the first iron core 301 from the second iron core 402, so that the relief groove 2 of the housing 1 is in an open state, and the measured wire passes through the relief groove 2 on the housing 1 and enters the housing 1.

[0036] Pull the handle 410 upward to compress the spring 411. The handle 410 drives the connecting plate 415 upward through the pull rod 409. The connecting plate 415 drives the adjusting block 413 upward through the connecting groove 414. The adjusting block 413 drives the second iron core 402 upward. During the upward movement of the second iron core 402, it drives a plurality of guiding blocks 407 to move within the corresponding guiding grooves 406. When the handle 410 drives the pull rod 409 upward to the limit position, at this time the spring 411 is in a compressed state, the second iron core 402 moves out of the clamping groove 302, and the second iron core 402 is separated from the first iron core 301 at this time. The second iron core 402 moves upward into the receiving groove 405. At this time, there are no other components in the sliding groove 404. Push the handle 410 to swing to the right. Under the cooperation of the sliding groove 404 and the housing 1, the entire sliding part 4 moves to the right along the track of the housing 1. As the sliding part 4 moves to the right, the relief groove 2 opened on the housing 1 is gradually revealed. When the effective passing area of the relief groove 2 is large enough, release the handle 410. Under the reset action of the spring 411, the pull rod 409 moves downward. The pull rod 409 drives the adjusting block 413 to move downward through the cooperation of the connecting plate 415 and the connecting groove 414. The adjusting block 413 drives the second iron core 402 to move downward. The second iron core 402 drives the guiding block 407 to move downward in the guiding groove 406. When the lower end of the second iron core 402 contacts the surface of the housing 1, the position of the sliding part 4 is limited. At this time, move the housing 1 so that the wire to be measured is located within the housing 1.

[0037] Then close the housing 1, pull the handle 410 upward to 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. When the left end of the sliding block 401 contacts the limiting plate 412, push the handle 410 to move downward. The pull rod 409 moves downward under the reset acting forces of the handle 410 and the spring 411. The pull rod 409 drives the adjusting block 413 and the second iron core 402 to move downward through the connecting plate 415 and the connecting groove 414. Since both end faces of the second iron core 402 and both end faces of the first iron core 301 are inclined surfaces, their inclined states are as 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 with 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 matches 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, thereby reducing the air gap after matching, and due to the inclination of the inclined surface, the downward moving position of the second core 402 is limited, thereby reducing the air gap after matching, and further, the matching position of the second core 402 and the first core 301 is preliminarily limited by the limiting plate 412, and the matching is corrected by the adjusting block 413 during the process of the pull rod 409 driving the second core 402 to move downward, and the spring 411 provides continuous matching pressure, and the matching 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, thereby reducing the air gap after matching and improving the accuracy of the detection result.

[0038] Embodiment 2 The traditional shielding solution uses attached high-permeability magnetic materials to construct a magnetic shielding layer. However, since the core joint needs to be moved, the two core shielding layers need to be attached. In order to meet the end-to-end connection of the core, a concession setting is required to avoid motion interference. However, the concession setting causes a physical breakpoint at the joint, and a nonlinear magnetic resistance cross-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.

[0039] See also Figures 1 to 7 As shown, 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 and cross-join with the fixed shielding layer 303 to form a magnetic leakage prevention structure without dead angles.

[0040] 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.

[0041] 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 portion of the first iron core 301 located in the make way slot 2 cannot be effectively wrapped. In order to compensate for this defect, a movable shielding layer 403 is wrapped on the surface of the sliding block 401, 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 is disconnected from the second iron core 402. When the first iron core 301 and the second iron core 402 are matched, the sliding block 401 moves to the make way slot 2 of the shell 1. The sliding block 401 drives the movable shielding layer 403 to move to the make way slot 2 of the shell 1. At this time, Figure 2 As shown, the movable shielding layer 403 and the fixed shielding layer 303 are staggeredly docked to completely wrap 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 staggeredly 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.

[0042] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An opening and closing type current transformer, comprising a housing, wherein a relief groove is formed in the housing, and it is characterized in that, Also includes: The fixing part includes a first iron core, the first iron core is located in the shell, a slot corresponding to the give way slot is opened on the first iron core, an induction coil is wound on the first iron core, multiple outer surfaces of the first iron core are provided with a fixed shielding layer, and the fixed shielding layer is located between the first iron core and the shell; The sliding part includes a sliding block, which is sleeved on the shell and slidably connected to the shell. The sliding block is provided with a second iron core that can cooperate with the connecting groove. 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 angle.

2. The split-type current transformer according to claim 1, wherein Two connection terminals are arranged 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, wherein, 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, wherein The sliding block is provided with a sliding groove, and the sliding block is slidably connected with the housing through the sliding groove.

5. The split-type current transformer according to claim 4, wherein, 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 give way groove.

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

7. The split type current transformer according to claim 6, wherein, 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 a spring is mounted on the pull rod and is 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 clamping slot is fan-shaped, and the circumference of the clamping slot on a side close to the center of the first iron core is smaller than the circumference of the side away from the center of the first iron core.

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

10. The opening and closing type current transformer according to claim 9, characterized in that, An adjusting block is fixedly connected to the upper end of the second iron core, an inverted T-shaped connecting groove is provided on the adjusting block, and a connecting plate is fixedly connected to the lower end of the pull rod, and the connecting plate is slidably connected to the connecting groove.

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