Current transformer, current transformer experimental device and experimental method

Abstract

The invention discloses a current transformer, a current transformer experiment device and an experiment method, and belongs to the technical field of electrical variable measurement, the current transformer comprises a shell, the surface of which is provided with a first terminal and a second terminal; a primary winding; the change-over switch comprises a main body part and a control knob, and the main body part is provided with a fifth terminal, a sixth terminal and a seventh terminal; a first-turn tap, a tail-turn tap and a middle tap are led out from the first secondary winding; the second terminal can be connected to different positions of the first secondary winding by adjusting the control knob to change the working state of the change-over switch, the purpose of changing the current ratio is achieved, external connecting wires connected to the first terminal and the second terminal do not need to be disassembled and assembled, and the transformer is suitable for the situation that the installation space is narrow or the transformation ratio needs to be completed in a short time. The current transformer experiment device comprises a first adjustable resistor and the current transformer. According to the experiment method, the current transformer experiment device is used for carrying out a primary winding insulation resistance experiment.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring electric variables, and in particular to a current transformer, a current transformer experimental device and an experimental method. Background Art

[0002] A current transformer is an electrical device used in power systems to measure current in power lines. Conventional current transformers maintain a fixed current ratio between their primary and secondary windings. When the current ratio needs to be changed (such as due to increased load due to factory expansion), the current transformer is typically replaced or a pre-installed multi-tap current transformer is installed, with the ratio changed by replacing different terminal blocks. However, these methods require wiring disassembly and installation, making them unsuitable for installations with limited space or when the ratio needs to be changed quickly. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a current transformer, a current transformer experimental device and an experimental method.

[0004] A current transformer according to an embodiment of the first aspect of the present invention includes: The housing comprises a housing body and a steel plate provided at the bottom of the housing body, wherein a first terminal, a second terminal and two primary wiring seats are provided on the surface of the housing body; A primary winding, both ends of which are electrically connected to the two primary terminal blocks; a switching switch comprising a main body disposed within the housing body and a control knob disposed on the steel plate, the main body having a fifth terminal, a sixth terminal, and a seventh terminal, the switching switch having a first operating state and a second operating state, wherein in the first operating state, the fifth terminal and the sixth terminal are electrically connected, and in the second operating state, the fifth terminal and the seventh terminal are electrically connected; The first secondary winding has a first turn tap, a tail turn tap and a middle tap, and the first terminal, the second terminal, the sixth terminal and the seventh terminal are electrically connected to the first turn tap, the fifth terminal, the middle tap and the tail turn tap respectively.

[0005] The current transformer according to the embodiment of the first aspect of the present invention has at least the following technical effects: by setting a switching switch and adjusting the control knob to change the working state of the switching switch, the second terminal can be connected to different positions of the first and secondary windings to achieve the purpose of changing the current ratio. Moreover, the operation of changing the current ratio does not require disassembly and assembly of the external wiring connected to the first terminal and the second terminal, and is suitable for situations where the installation space is narrow or the transformation ratio needs to be completed in a short time.

[0006] According to some embodiments of the present invention, the main body includes a box body, a switching plate is provided in the box body, the switching plate is electrically connected to the fifth terminal, the switching plate has a fixed end and a swinging end, the fixed end is rotatably connected to the box body through a vertically arranged first rotating shaft, in the first working state, the swinging end abuts the front side of the sixth terminal, in the second working state, the swinging end abuts the front side of the seventh terminal, and the control knob is linked to the switching plate.

[0007] According to some embodiments of the present invention, in the first working state, the swing end is located at the left end of the switching plate, and in the second working state, the swing end is located at the right end of the switching plate.

[0008] According to some embodiments of the present invention, a rotating seat is provided on the outer rotating sleeve of the first rotating shaft, the switching plate is provided on the rotating seat, the rotating seat is provided with a cylindrical inner cavity coaxial with the first rotating shaft, an annular spring is provided in the inner cavity, the annular spring is electrically connected to the switching plate, the annular spring has a first section, a second section, a third section and a fourth section connected end to end, so that the third section tends to move away from the first section, the first section is fixedly connected to the inner wall of the inner cavity, the fifth terminal is eccentrically arranged on the front side of the top end of the first rotating shaft, and the fifth terminal abuts against the side of the third section facing away from the first section.

[0009] According to some embodiments of the present invention, the switching plate is connected to a first gear, the control knob is connected to a second gear, the first gear is meshed with the second gear, and the number of teeth of the first gear is smaller than the number of teeth of the second gear.

[0010] According to the second aspect of the embodiment of the present invention, the current transformer experimental device includes a first adjustable resistor and the above-mentioned current transformer, the first adjustable resistor includes a first resistor body arranged in the shell body and a first adjustment knob arranged on the steel plate, and the first adjustable resistor is electrically connected between the primary winding and the steel plate.

[0011] According to the current transformer experimental device of the second aspect embodiment of the present invention, there are at least the following technical effects: by setting the first adjustable resistor, the primary winding insulation fault is simulated to meet the needs of the primary winding insulation measurement experiment; in addition, by turning the first adjustment knob, the resistance value between the primary winding and the steel plate (i.e., grounding) can be adjusted, thereby simulating different fault conditions, which is conducive to improving the training effect.

[0012] According to some embodiments of the present invention, the current transformer experimental device also includes a second adjustable resistor, which includes a second resistor body arranged in the shell body and a second adjustment knob arranged on the steel plate, and the second adjustable resistor is electrically connected between the first secondary winding and the steel plate.

[0013] According to some embodiments of the present invention, the current transformer experimental device also includes a third adjustable resistor, which includes a third resistor body arranged in the shell body and a third adjustment knob arranged on the steel plate; the current transformer also includes a second secondary winding, and the third adjustable resistor is electrically connected between the second secondary winding and the primary winding.

[0014] According to the experimental method of the third embodiment of the present invention, a winding insulation resistance test is performed using the above-mentioned current transformer experimental device. The experimental method includes the following steps: Rotate the first adjustment knob to any position and measure the winding insulation resistance once; Adjust the position of the first adjustment knob and perform a winding insulation resistance measurement; The results of two primary winding insulation resistance measurements were compared and analyzed.

[0015] The experimental method according to the embodiment of the third aspect of the present invention has at least the following technical effects: by using the above-mentioned current transformer experimental device, the insulation resistance value of the primary winding can be adjusted during the experiment to obtain better training effects.

[0016] According to an experimental method of an embodiment of the fourth aspect of the present invention, a transformation ratio and polarity experiment is performed using the above-mentioned current transformer, and the experimental method includes the following steps: Adjusting the switch to the first working state and performing a transformation ratio and polarity check test; Adjusting the switch to the second working state and performing a transformation ratio and polarity check test; The results of the two ratio and polarity check tests were compared and analyzed.

[0017] According to the experimental method of the fourth aspect of the present invention, there are at least the following technical effects: by setting a switching switch, the first terminal and the second terminal are connected to different numbers of turns of the first and secondary windings, and different numbers of coil turns are configured, different experimental results are obtained to obtain better training effects.

[0018] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which: Figure 1 1 is a schematic diagram of the three-dimensional structure of a current transformer experimental device according to an embodiment of the present invention; Figure 2 is a perspective schematic diagram of a current transformer experimental device according to an embodiment of the present invention; Figure 3 yes Figure 2 Schematic diagram of the current transformer experimental device from another angle; Figure 4 yes Figure 2 A perspective diagram of a toggle switch in ; Figure 5 yes Figure 4 Schematic diagram of the three-dimensional structure of the rotating seat; Figure 6 yes Figure 5 A schematic top cross-sectional view of the first working state of the rotating seat in FIG. Figure 7 yes Figure 5 A schematic top cross-sectional view of the second working state of the rotating seat; Figure 8 yes Figure 5 A schematic top cross-sectional view of the intermediate state of the rotating seat in FIG. Figure 9 1 is a circuit diagram of a current transformer experimental device according to an embodiment of the present invention; In the attached figure: 010-shell body; 020-steel plate; 100-primary winding; 110-primary terminal block; 200-first and second windings; 201-first turn tap; 202-last turn tap; 203-middle tap; 300-second and second windings; 400-switch; 410-control knob; 420-box; 431-first gear; 432-second gear; 440-rotating seat; 441-first section; 443-third section; 4 45-inner cavity; 450-switching plate; 460-first rotating shaft; 510-first adjustable resistor; 511-first adjusting knob; 520-second adjustable resistor; 521-second adjusting knob; 530-third adjustable resistor; 531-third adjusting knob; 601-first terminal; 602-second terminal; 603-third terminal; 604-fourth terminal; 605-fifth terminal; 606-sixth terminal; 607-seventh terminal. DETAILED DESCRIPTION

[0020] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0021] In the description of the present invention, it should be understood that the directions or positional relationships indicated, such as up, down, front, back, left, and right, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the meaning of "several" is one or more, the meaning of "more" is more than two, and the meanings of "greater than", "less than", and "exceed" are not inclusive of the number itself, while the meanings of "above", "below", and "within" are inclusive of the number itself. If there is a description of first or second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0022] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0023] Reference below Figures 1 to 9 A current transformer, a current transformer experimental device, and an experimental method according to an embodiment of the present invention are described.

[0024] The current transformer of the first embodiment of the present invention, referring to Figure 1 and Figure 2 , including a housing, a primary winding 100 , a first secondary winding 200 and a switch 400 .

[0025] The shell includes a shell body 010 and a steel plate 020 arranged at the bottom of the shell body 010. The shell body 010 is an epoxy resin material component, and the steel plate 020 is arranged horizontally. The shell body 010 can be connected to the steel plate 020 by bolt connection or other appropriate methods.

[0026] The surface of the shell body 010 is provided with a first terminal 601, a second terminal 602 and two primary terminal holders 110. The first terminal 601 and the second terminal 602 are both arranged on the left side of the shell body 010. The first terminal 601 and the second terminal 602 are used to electrically connect to the first and secondary windings 200, and the primary terminal holder 110 is used to electrically connect to the primary winding 100.

[0027] The two ends of the primary winding 100 are electrically connected to two primary terminal blocks 110 respectively. The primary winding 100 includes a horizontal bar and two vertical bars arranged in the shell body 010. The horizontal bar and the vertical bars are both copper components. The horizontal bar is connected between the bottom ends of the two vertical bars. The top ends of the two vertical bars pass through the top wall of the shell body 010 and are connected to the two primary terminal blocks 110 one by one.

[0028] The switching switch 400 includes a control knob 410 arranged on the steel plate 020 and a main body arranged in the shell body 010. The control knob 410 is rotatably arranged on the steel plate 020. The bottom of the control knob 410 is flush with the steel plate 020. The control knob 410 is provided with a cross slot or a slotted slot for easy rotation using a screwdriver. The switching switch 400 has a first working state and a second working state. The control knob 410 is used to switch the switching switch 400 between the first working state and the second working state; the main body has a fifth terminal 605, a sixth terminal 606 and a seventh terminal 607. In the first working state, the sixth terminal 606 and the fifth terminal 605 are electrically connected. In the second working state, the seventh terminal 607 and the fifth terminal 605 are electrically connected.

[0029] The first and second windings 200 have a first-turn tap 201, an intermediate tap 203, and a tail-turn tap 202. The first and second windings include a support ring sleeved on the outside of the crossbar, an iron core sleeved on the outside of the support ring, and a secondary coil wound on the iron core. The support ring is an insulating material component. The secondary coil has a first turn, a tail turn, and an intermediate turn. The intermediate turn is electrically connected to the first turn and tail turn paper pieces. The first turn tap 201 is connected to the first turn, the tail turn tap 202 is connected to the tail turn, the intermediate tap 203 is connected to the intermediate turn, the first terminal 601 is electrically connected to the first turn tap 201, the second terminal 602 is electrically connected to the fifth terminal 605, the sixth terminal 606 is electrically connected to the intermediate tap 203, and the seventh terminal 607 is electrically connected to the tail-turn tap 202. The above electrical connection method can be connected through a flexible wire.

[0030] During the initial phase of a factory's operation, when the factory's power load is relatively low, the current transformer can be adjusted to a relatively low current operating state to avoid excessive current measurement errors. During factory expansion, when the factory's power load increases, the current transformer can be adjusted to a relatively high current operating state to prevent overload damage to the current transformer, which could affect factory production. By setting a toggle switch 400 and adjusting the control knob 410 to change the operating state of the toggle switch 400, the second terminal 602 can be connected to different positions of the first and second windings 200, thereby changing the current ratio. Furthermore, changing the current ratio does not require disassembly or assembly of external wiring connected to the first and second terminals 601, 602, making it suitable for applications where installation space is limited or the ratio needs to be changed quickly.

[0031] In some embodiments of the present invention, the main body includes a housing 420, which is fixedly mounted on a steel plate 020. A switching plate 450 is disposed within the housing 420. The switching plate 450 has a swinging end and a fixed end. The switching plate 450 is electrically connected to the fifth terminal 605, and the fixed end is rotatably connected to the housing 420 via a vertically disposed first rotating shaft 460. In a first operating state, the swinging end abuts the front side of the sixth terminal 606, and in a second operating state, the swinging end abuts the front side of the seventh terminal 607. The switching plate 450 is interlocked with the control knob 410. Rotating the control knob 410 thus rotates the switching plate 450, thereby switching the fifth terminal 605 between being electrically connected to the sixth terminal 606 and being electrically connected to the seventh terminal 607, thereby changing the current ratio.

[0032] In some embodiments of the present invention, in the first working state, the swing end is located at the left end of the switching plate 450, and in the second working state, the swing end is located at the right end of the switching plate 450. The box body 420 is an insulating material component, referring to Figure 5 The sixth terminal 606 is arranged on the left side of the seventh terminal 607. The sixth terminal 606 includes a horizontal portion and a vertical portion. The vertical portion vertically penetrates the top wall of the box body 420, and the horizontal portion extends to the right from the bottom end of the vertical portion. A rearwardly recessed docking groove is provided on the front side of the right end of the horizontal portion. The seventh terminal 607 and the sixth terminal 606 are arranged in a left-right mirror-symmetrical structure.

[0033] In this way, the distance between the seventh terminal 607 and the sixth terminal 606 is larger, and the moving path of the swing end is longer when switching the working state, reducing the risk of short circuit; a docking column is provided on the upper side of the swing end of the switching plate 450, and the docking column is adapted to the docking groove. In the first working state, the docking column is provided in the docking groove and abuts against the groove wall of the docking groove. The switching plate 450 and the docking column are both copper or other conductive material components.

[0034] In some embodiments of the present invention, a rotating seat 440 is provided on the outer rotating sleeve of the first rotating shaft 460 . The first rotating shaft 460 is vertically arranged, and the lower end of the first rotating shaft 460 is fixedly connected to the box body 420 .

[0035] The switching plate 450 is arranged on the rotating base 440, and the fixed end of the switching plate 450 is fixedly arranged on the rotating base 440. The rotating base 440 is sleeved on the top of the first rotating shaft 460 from top to bottom. The rotating base 440 is provided with a cylindrical inner cavity 445 coaxial with the first rotating shaft 460. The inner cavity 445 is provided on the upper side of the first rotating shaft 460. An annular spring is provided in the inner cavity 445, and the switching plate 450 is electrically connected to the annular spring.

[0036] The annular spring piece has a first section 441, a second section, a third section 443 and a fourth section connected end to end, so that the third section 443 tends to move away from the first section 441. The first section 441 is fixedly connected to the inner wall of the inner cavity 445, and the switching plate 450 can be connected to the first section 441 via a wire; the fifth terminal 605 is eccentrically arranged at the front side of the top end of the first rotating shaft 460, and the fifth terminal 605 is arranged in the inner cavity 445. The fifth terminal 605 can be connected to the second terminal 602 via a wire, and the fifth terminal 605 abuts against the side of the third section 443 facing away from the first section 441.

[0037] By providing an annular spring piece and eccentrically arranging the fifth terminal 605, the annular spring piece has the tendency to move in the inner cavity 445 to the side where the distance between the fifth terminal 605 and the inner wall of the inner cavity 445 is larger (i.e., the rear side of the fifth terminal 605), that is, the annular spring piece has the tendency to rotate until the first section 441 moves to the rear end of the inner cavity 445, so that the switching plate 450 has the tendency to swing backward, thereby enabling the switching plate 450 to maintain abutment with the seventh terminal 607 or the sixth terminal 606, and to have good contact. At the same time, the third section 443 of the annular spring piece always maintains abutment with the fifth terminal 605, thereby achieving the purpose of maintaining good contact between the switching plate 450 and the fifth terminal 605 during relative rotation and the purpose of maintaining good contact after the switching plate 450 switches between the sixth terminal 606 and the seventh terminal 607.

[0038] The annular shrapnel can be a copper shrapnel or other conductor shrapnel, refer to Figure 6 In the first working state, the annular spring is located on the left rear side of the fifth terminal 605, the first section 441 is fixedly arranged on the left rear wall of the inner cavity 445, and the first section 441 has a tendency to move rightward and rearward, so that the switching plate 450 abuts against the sixth terminal 606; Figure 7 In the second working state, the annular spring is located on the right rear side of the fifth terminal 605, the first section 441 is fixedly arranged on the right rear wall of the inner cavity 445, and the first section 441 has a tendency to move to the left rear, so that the switching plate 450 abuts against the seventh terminal 607; the switching switch 400 has an intermediate state, referring to Figure 8 In the intermediate state, the annular spring is located in front of the fifth terminal 605, and the first section 441 is fixedly arranged on the front wall of the inner cavity 445. At this time, the adjustment knob is manipulated to make the first section 441 slightly move to the left, and the switching switch 400 tends to spontaneously switch to the first working state. The adjustment knob is manipulated to make the first section 441 slightly move to the right, and the switching switch 400 tends to spontaneously switch to the second working state, which facilitates the switching operation of the staff.

[0039] In some embodiments of the present invention, reference Figure 4The switch plate 450 is connected to the first gear 431, and the control knob 410 is connected to the second gear 432. The second gear 432 meshes with the first gear 431. The number of teeth of the first gear 431 is smaller than that of the second gear 432. The second gear 432 and the first gear 431 can both be insulators. The first gear 431 is sleeved on the outside of the rotating base 440. The rotating base 440 and the first gear 431 can be an integral component. The second gear 432 is set above the control knob 410. A second rotating shaft is fixedly connected between the second gear 432 and the control knob 410. The second rotating shaft passes through the bottom wall of the box body 420. Turning the control knob 410 can rotate the second gear 432, thereby driving the first gear 431 to make the switch plate 450 swing. By setting the first gear 43 The number of teeth of the first gear 431 is smaller than that of the second gear 432. By rotating the control knob 410 at a smaller angle, the rotating base 440 can be rotated at a larger angle to complete the switching of the working state, which is convenient for the staff to adjust. At the same time, after exceeding the intermediate state, the rotating base 440 rotates under the action of the annular spring piece and drives the second gear 432. Setting the number of teeth of the first gear 431 to be smaller than that of the second gear 432 can also make the second gear 432 less obstructive to the rotation of the rotating base 440, so that the elastic force of the annular spring piece can be sufficient to drive the rotating base 440.

[0040] In the prior art, technical skills training for current transformers usually uses the same current transformers as those used in production sites. This type of current transformer equipment has fewer types of failures, which affects the training effect. Therefore, the second embodiment of the present invention further proposes a current transformer experimental device.

[0041] The current transformer test device according to the second embodiment of the present invention includes a first adjustable resistor 510 and the aforementioned current transformer. The first adjustable resistor 510 includes a first adjustment knob 511 disposed on a steel plate 020 and a first resistor body disposed within a housing 010. The first adjustable resistor 510 is electrically connected between the primary winding 100 and the steel plate 020. The first resistor body is fixedly connected to the steel plate 020, and the first adjustable resistor 510 can be connected between a vertical rod and the steel plate 020 via a flexible conductor. The first adjustment knob 511 is used to control the resistance value of the first adjustable resistor 510. In this embodiment, the first adjustable resistor 510 is provided to simulate an insulation fault in the primary winding 100 to meet the requirements of the primary winding 100 insulation measurement experiment. In addition, rotating the first adjustment knob 511 can adjust the resistance value between the primary winding 100 and the steel plate 020 (i.e., ground), thereby simulating different fault conditions and improving training effectiveness.

[0042] In some embodiments of the present invention, the current transformer experimental device further includes a second adjustable resistor 520, which includes a second adjustment knob 521 disposed on the steel plate 020 and a second resistor body disposed within the housing body 010. The second adjustable resistor 520 is electrically connected between the first secondary winding 200 and the steel plate 020. The second resistor body is fixedly connected to the steel plate 020, and the second adjustable resistor 520 can be connected between the steel plate 020 and the secondary coil of the first secondary winding 200 via a flexible wire. The second adjustment knob 521 is used to control the resistance value of the second adjustable resistor 520.

[0043] In this embodiment, a second adjustable resistor 520 is provided to simulate a secondary winding insulation fault to meet the requirements of the secondary winding insulation measurement experiment. In addition, by turning the second adjustment knob 521, the resistance value between the first secondary winding 200 and the steel plate 020 (i.e., ground) can be adjusted, thereby simulating different fault conditions, which is conducive to improving training effects.

[0044] In some embodiments of the present invention, reference Figure 9 The current transformer experimental device also includes a third adjustable resistor 530, which includes a third adjustment knob 531 arranged on the steel plate 020 and a third resistor body arranged in the shell body 010; the current transformer also includes a second secondary winding 300, and the third adjustable resistor 530 is electrically connected between the second secondary winding 300 and the primary winding 100.

[0045] The structure of the second secondary winding 300 is identical to that of the first secondary winding 200, namely, it also includes a support ring, an iron core, and a secondary coil. A third terminal 603 and a fourth terminal 604 are provided on the surface of the housing 010. One end of the secondary coil of the second secondary winding 300 is connected to the third terminal 603 via a flexible wire, and the other end of the secondary coil of the second secondary winding 300 is connected to the fourth terminal 604 via a flexible wire. The third resistor body is fixedly connected to the steel plate 020. The third adjustable resistor 530 can be connected between the vertical rod and the secondary coil of the second secondary winding 300 via a flexible wire. A third adjustment knob 531 is used to control the resistance of the third adjustable resistor 530. In this embodiment, the third adjustable resistor 530 is provided to simulate an insulation fault between the primary winding 100 and the secondary winding. Turning the third adjustment knob 531 adjusts the resistance between the primary winding 100 and the secondary winding, thereby simulating different fault conditions and improving training effectiveness.

[0046] The first, second, and third adjustable insulation resistors can all be conventional rotary adjustable resistors, such as potentiometers, and their specific structures are not described in detail herein. The first, second, and third adjustment knobs 511, 521, and 531 are each provided with a cross slot or a slotted slot for easy rotation with a screwdriver. The first, second, and third adjustment knobs 511, 521, 531, and control knob 410 are all rotatably embedded in the underside of the steel plate 020 and flush with the underside of the steel plate 020 for stable placement. Indicator arrows are provided on the underside of the steel plate 020 corresponding to each knob.

[0047] The current transformer experimental device of the present invention, by setting a first adjustable resistor 510, a second adjustable resistor 520 and a third adjustable resistor 530, can more conveniently simulate the grounding fault of the primary winding 100, the grounding fault of the secondary winding and the insulation fault of the primary and secondary windings, etc., to ensure that during the teaching process, the trainees can safely and conveniently access sufficient faults and make contact, effectively reducing the problem of the lack of fault types in existing teaching, and effectively improving the training effect of the trainees. In addition, by setting the switching switch 400, the trainees can access and understand the fault of the short circuit caused by the adhesion of part of the secondary coil under the premise of ensuring safety and convenience, further increasing the types of faults. The shell body 010 is detachably set on the steel plate 020 by bolt connection, which is more convenient for subsequent maintenance and repair of the current transformer, reducing teaching costs and being able to more clearly show the internal structure of the current transformer to the trainees. The current transformer experimental device of the present invention can be used to carry out experiments such as a current transformer primary coil insulation resistance measurement experiment, a current transformer secondary coil insulation resistance measurement experiment, a current transformer AC withstand voltage test, a current transformer current ratio and polarity inspection experiment, and a current transformer winding DC resistance measurement experiment. Different experimental results can be obtained by configuring different numbers of coil turns and different insulation resistance values, which is conducive to obtaining better training effects.

[0048] The experimental method of the third embodiment of the present invention uses the above-mentioned current transformer experimental device to perform an insulation resistance test of the primary winding 100. The experimental method includes the following steps: S110, rotating the first adjustment knob 511 to any position and measuring the insulation resistance of the winding 100; S120, adjusting the position of the first adjustment knob 511 and measuring the insulation resistance of the primary winding 100; S130 , performing comparative analysis on the two insulation resistance measurement results of the primary winding 100 .

[0049] By using the above-mentioned current transformer test device, the insulation resistance value of the primary winding 100 can be adjusted during the experiment to obtain better training results. Similarly, the experimental method of the present invention can also use the above-mentioned current transformer test device to conduct a secondary winding insulation resistance test; and can also use the above-mentioned current transformer test device to conduct an insulation resistance test between the primary winding 100 and the secondary winding. Among them, measuring the insulation resistance of the primary winding 100 of the current transformer, measuring the insulation resistance of the secondary winding, and measuring the insulation resistance between the primary winding 100 and the secondary winding are all conventional technical means in this field, and their specific steps are not repeated here.

[0050] The experimental method of the fourth embodiment of the present invention uses the above-mentioned current transformer to perform a transformation ratio and polarity experiment, and the experimental method includes the following steps: S210, adjusting the switch 400 to the first working state and performing a transformation ratio and polarity check test; S220, adjusting the switch 400 to the second working state and performing a transformation ratio and polarity check test; S230, comparing and analyzing the results of the two transformation ratio and polarity check tests.

[0051] By setting the switching switch 400, different numbers of turns of the first and second windings 200 are connected by means of the first terminal 601 and the second terminal 602, and different numbers of coil turns are configured to obtain different experimental results, thereby obtaining better training effects. Among them, performing ratio and polarity check tests on current transformers is a conventional technical means in this field, and its specific steps are not described in detail here. In addition, by using the first terminal 601 and the second terminal 602 to connect to different numbers of turns of the first and second windings 200, the problem of short circuit caused by adhesion of part of the first and second coils can be simulated. Under the premise of ensuring safety and convenience, the training personnel can be exposed to and understand the fault of short circuit caused by adhesion of part of the secondary coil, thereby further improving the types of faults.

[0052] The above specifically describes the preferred embodiments of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A current transformer, characterized in that: include: The housing comprises a housing body and a steel plate provided at the bottom of the housing body, wherein a first terminal, a second terminal and two primary wiring seats are provided on the surface of the housing body; A primary winding, both ends of which are electrically connected to the two primary terminal blocks; a switching switch comprising a main body disposed within the housing body and a control knob disposed on the steel plate, the main body having a fifth terminal, a sixth terminal, and a seventh terminal, the switching switch having a first operating state and a second operating state, wherein in the first operating state, the fifth terminal and the sixth terminal are electrically connected, and in the second operating state, the fifth terminal and the seventh terminal are electrically connected; The first secondary winding has a first turn tap, a tail turn tap and a middle tap, and the first terminal, the second terminal, the sixth terminal and the seventh terminal are electrically connected to the first turn tap, the fifth terminal, the middle tap and the tail turn tap respectively.

2. The current transformer according to claim 1, characterized in that: The main body includes a box body, a switching plate is provided in the box body, the switching plate is electrically connected to the fifth terminal, the switching plate has a fixed end and a swinging end, the fixed end is rotatably connected to the box body via a vertically arranged first rotating shaft, in the first working state, the swinging end abuts against the front side of the sixth terminal, in the second working state, the swinging end abuts against the front side of the seventh terminal, and the control knob is linked to the switching plate.

3. The current transformer according to claim 2, characterized in that: In the first working state, the swing end is located at the left end of the switching plate, and in the second working state, the swing end is located at the right end of the switching plate.

4. The current transformer according to claim 3, characterized in that: A rotating seat is provided on the outer rotating sleeve of the first rotating shaft, and the switching plate is provided on the rotating seat. The rotating seat is provided with a cylindrical inner cavity coaxial with the first rotating shaft, and an annular spring is provided in the inner cavity. The annular spring is electrically connected to the switching plate. The annular spring has a first section, a second section, a third section and a fourth section connected end to end, so that the third section tends to move away from the first section, and the first section is fixedly connected to the inner wall of the inner cavity. The fifth terminal is eccentrically arranged on the front side of the top end of the first rotating shaft, and the fifth terminal abuts against the side of the third section facing away from the first section.

5. The current transformer according to claim 3, characterized in that: The switching plate is connected to a first gear, the control knob is connected to a second gear, the first gear is meshed with the second gear, and the number of teeth of the first gear is smaller than the number of teeth of the second gear.

6. A current transformer experimental device, characterized in that: It includes a first adjustable resistor and a current transformer as described in any one of claims 1 to 5, wherein the first adjustable resistor includes a first resistor body arranged in the shell body and a first adjustment knob arranged on the steel plate, and the first adjustable resistor is electrically connected between the primary winding and the steel plate.

7. The current transformer experimental device according to claim 6, characterized in that: It also includes a second adjustable resistor, which includes a second resistor body arranged in the shell body and a second adjustment knob arranged on the steel plate. The second adjustable resistor is electrically connected between the first secondary winding and the steel plate.

8. The current transformer experimental device according to claim 6, characterized in that: It also includes a third adjustable resistor, which includes a third resistor body arranged in the shell body and a third adjustment knob arranged on the steel plate; the current transformer also includes a second secondary winding, and the third adjustable resistor is electrically connected between the second secondary winding and the primary winding.

9. An experimental method, characterized in that: A winding insulation resistance test is performed using the current transformer test device according to claim 6, wherein the test method comprises the following steps: Rotate the first adjustment knob to any position and measure the winding insulation resistance once; Adjust the position of the first adjustment knob and perform a winding insulation resistance measurement; The results of two primary winding insulation resistance measurements were compared and analyzed.

10. An experimental method, characterized in that: A transformation ratio and polarity experiment is performed using the current transformer according to any one of claims 1 to 5, wherein the experimental method comprises the following steps: Adjusting the switch to the first working state and performing a transformation ratio and polarity check test; Adjusting the switch to the second working state and performing a transformation ratio and polarity check test; The results of the two ratio and polarity check tests were compared and analyzed.

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