Current transformer, current transformer experimental setup and experimental method

Abstract

This invention discloses a current transformer, a current transformer experimental apparatus, and an experimental method, belonging to the field of electrical variable measurement technology. The current transformer includes: a housing with a first terminal and a second terminal on its surface; a primary winding; a switching switch including a main body and a control knob, the main body having a fifth terminal, a sixth terminal, and a seventh terminal; and first and secondary windings with a first-turn tap, a last-turn tap, and an intermediate tap. Adjusting the control knob changes the operating state of the switching switch, allowing the second terminal to be connected to different positions on the first and secondary windings, thus changing the current ratio. This eliminates the need to disassemble or reassemble the external wiring connected to the first and second terminals, making it suitable for situations with limited installation space or where a rapid transformation ratio needs to be achieved. The current transformer experimental apparatus includes a first adjustable resistor and the aforementioned current transformer; the experimental method uses the aforementioned current transformer experimental apparatus to conduct a primary winding insulation resistance test.

Description

Technical Field

[0001] This invention relates to the field of electrical variable measurement technology, and in particular to a current transformer, a current transformer experimental apparatus, and an experimental method. Background Technology

[0002] Current transformers are electrical devices used in power systems to measure the current in power lines. In a conventional current transformer, the current ratio between the primary and secondary windings remains constant. When a change in the current ratio is needed (such as increased load due to factory expansion), the current transformer is typically replaced, or a multi-tap current transformer is pre-installed, and the ratio is achieved by changing different terminals. However, such methods require wiring disassembly and reassembly, making them unsuitable for situations with limited installation space or where a rapid ratio change is required. 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 proposes a current transformer, a current transformer experimental apparatus, and an experimental method.

[0004] A current transformer according to a first aspect of the present invention includes:

[0005] The outer casing includes a casing body and a steel plate disposed at the bottom of the casing body. The surface of the casing body is provided with a first terminal, a second terminal and two primary terminal blocks.

[0006] The primary winding has its two ends electrically connected to the two primary terminals respectively;

[0007] A switching switch includes a main body disposed within the housing body and a control knob disposed on the steel plate. The main body has a fifth terminal, a sixth terminal, and a seventh terminal. The switching switch has a first working state and a second working state. In the first working state, the fifth terminal and the sixth terminal are electrically connected. In the second working state, the fifth terminal and the seventh terminal are electrically connected.

[0008] The first and second windings have a first-turn tap, a last-turn tap, and an intermediate tap. 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 intermediate tap, and the last-turn tap, respectively.

[0009] The current transformer according to 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 second windings, thereby changing the current ratio. Moreover, the operation of changing the current ratio does not require disassembling or assembling the external wiring connected to the first and second terminals, which is suitable for situations where the installation space is narrow or the transformation ratio needs to be completed in a short time.

[0010] According to some embodiments of the present invention, the main body includes a housing, and a switching plate is provided inside the housing. The switching plate is electrically connected to the fifth terminal. The switching plate has a fixed end and a swing end. The fixed end is rotatably connected to the housing via a vertically arranged first rotating shaft. In the first working state, the swing end abuts against the front side of the sixth terminal. In the second working state, the swing end abuts against the front side of the seventh terminal. The control knob is linked to the switching plate.

[0011] 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.

[0012] According to some embodiments of the present invention, a rotating seat is rotatably sleeved on the outer side of the first rotating shaft, and the switching plate is disposed on the rotating seat. The rotating seat has a cylindrical inner cavity coaxial with the first rotating shaft. An annular spring is disposed in the inner cavity. The annular spring is electrically connected to the switching plate. The annular spring has a first segment, a second segment, a third segment, and a fourth segment connected end to end, such that the third segment tends to move away from the first segment. The first segment is fixedly connected to the inner wall of the inner cavity. The fifth terminal is eccentrically disposed on the front side of the top end of the first rotating shaft, and the fifth terminal abuts against the side of the third segment away from the first segment.

[0013] 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 meshes with the second gear, and the number of teeth of the first gear is less than the number of teeth of the second gear.

[0014] According to a second aspect of the present invention, a current transformer experimental apparatus includes a first adjustable resistor and the aforementioned current transformer. The first adjustable resistor includes a first resistor body disposed within the housing body and a first adjustment knob disposed on the steel plate. The first adjustable resistor is electrically connected between the primary winding and the steel plate.

[0015] The current transformer experimental apparatus according to a second aspect of the present invention has at least the following technical effects: by setting a first adjustable resistor, a primary winding insulation fault can be simulated to meet the requirements of the primary winding insulation measurement experiment; in addition, rotating the first adjustment knob can adjust the resistance value between the primary winding and the steel plate (i.e., grounding), thereby simulating different fault conditions, which is beneficial to improving the training effect.

[0016] According to some embodiments of the present invention, the current transformer experimental apparatus further includes a second adjustable resistor, the second adjustable resistor including a second resistor body disposed within the housing body and a second adjustment knob disposed on the steel plate, the second adjustable resistor being electrically connected between the first secondary winding and the steel plate.

[0017] According to some embodiments of the present invention, the current transformer experimental apparatus further includes a third adjustable resistor, the third adjustable resistor including a third resistor body disposed within the housing body and a third adjustment knob disposed on the steel plate; the current transformer further includes a second secondary winding, and the third adjustable resistor is electrically connected between the second secondary winding and the primary winding.

[0018] According to the experimental method of the third aspect of the present invention, a primary winding insulation resistance test is performed using the above-described current transformer experimental apparatus. The experimental method includes the following steps:

[0019] Rotate the first adjustment knob to any position and perform a winding insulation resistance measurement;

[0020] Adjust the position of the first adjustment knob and perform a winding insulation resistance measurement;

[0021] The results of two measurements of the insulation resistance of the primary winding were compared and analyzed.

[0022] The experimental method according to the third aspect of the present invention has at least the following technical effects: by using the above-described current transformer experimental device, the insulation resistance value of the primary winding can be adjusted during the experiment to obtain better training results.

[0023] According to the experimental method of the fourth aspect of the present invention, the current transformer described above is used to perform a transformation ratio and polarity experiment, and the experimental method includes the following steps:

[0024] Adjust the switching switch to the first working state and perform a ratio and polarity check test;

[0025] Adjust the switching switch to the second working state and perform a ratio and polarity check test;

[0026] The results of the two ratio and polarity check tests were compared and analyzed.

[0027] The experimental method according to the fourth aspect of the present invention has at least the following technical effects: by setting a switching switch, different numbers of turns of the first and second terminals are connected to the first and second windings, and different numbers of coil turns are configured, resulting in different experimental results and thus obtaining a better training effect.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0030] Figure 1 This is a three-dimensional structural schematic diagram of the current transformer experimental device according to an embodiment of the present invention;

[0031] Figure 2 This is a perspective view of the current transformer experimental apparatus according to an embodiment of the present invention;

[0032] Figure 3 yes Figure 2 A schematic diagram of the current transformer experimental setup from another angle;

[0033] Figure 4 yes Figure 2 A perspective view of the toggle switch in the diagram;

[0034] Figure 5 yes Figure 4 A three-dimensional structural diagram of the rotating seat in the middle;

[0035] Figure 6 yes Figure 5 A top sectional view of the rotating seat in its first working state;

[0036] Figure 7 yes Figure 5 A top sectional view of the rotating seat in its second working state;

[0037] Figure 8 yes Figure 5 A top sectional view of the rotating seat in its intermediate state;

[0038] Figure 9 This is a circuit diagram of the current transformer experimental device according to an embodiment of the present invention;

[0039] In the attached image:

[0040] 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 - Intermediate tap; 300 - Second and third windings; 400 - Switch; 410 - Control knob; 420 - Housing; 431 - First gear; 432 - Second gear; 440 - Rotating base; 441 - First section; 443 - Third section; 4 45-Inner cavity; 450-Switching plate; 460-First rotating shaft; 510-First adjustable resistor; 511-First adjustment knob; 520-Second adjustable resistor; 521-Second adjustment knob; 530-Third adjustable resistor; 531-Third adjustment knob; 601-First terminal; 602-Second terminal; 603-Third terminal; 604-Fourth terminal; 605-Fifth terminal; 606-Sixth terminal; 607-Seventh terminal. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number, while "above," "below," "within," etc., are understood to include the stated number. If "first" or "second" is used, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0043] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0044] The following is for reference. Figures 1 to 9 This invention describes a current transformer, a current transformer experimental apparatus, and an experimental method according to embodiments of the present invention.

[0045] The current transformer of the first aspect of the present invention, referred to Figure 1 and Figure 2 It includes a housing, a primary winding 100, a first and second secondary winding 200, and a switching switch 400.

[0046] The outer shell includes a shell body 010 and a steel plate 020 disposed 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 bolts or other suitable means.

[0047] The surface of the housing body 010 is provided with a first terminal 601, a second terminal 602 and two primary terminal blocks 110. The first terminal 601 and the second terminal 602 are both located on the left side of the housing body 010. The first terminal 601 and the second terminal 602 are used to electrically connect with the first and second windings 200, and the primary terminal blocks 110 are used to electrically connect with the primary windings 100.

[0048] The two ends of the primary winding 100 are electrically connected to two primary terminals 110 respectively. The primary winding 100 includes a horizontal bar and two vertical bars disposed in the housing body 010. Both the horizontal bar and the vertical bars are made of copper. The horizontal bar is connected between the bottom ends of the two vertical bars. The top ends of the two vertical bars penetrate the top wall of the housing body 010 and are connected to the two primary terminals 110 respectively.

[0049] The switch 400 includes a control knob 410 disposed on a steel plate 020 and a main body disposed within a housing body 010. The control knob 410 is rotatably disposed on the steel plate 020, and the bottom of the control knob 410 is flush with the steel plate 020. The control knob 410 is provided with a cross-shaped groove or a slotted groove to facilitate rotation with a screwdriver. The switch 400 has a first working state and a second working state. The control knob 410 is used to switch the 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.

[0050] The first and second windings 200 have a first turn tap 201, an intermediate tap 203, and a last 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 last turn, and an intermediate turn. The intermediate turn is electrically connected to the first turn and the last turn. The first turn tap 201 is connected to the first turn, the last turn tap 202 is connected to the last turn, and 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 last turn tap 202. The above electrical connection can be made by means of flexible wires.

[0051] When a factory is initially put into operation, its electrical load is relatively small. The current transformer can be adjusted to a lower current operating state to avoid excessive measurement errors. During factory expansion, as the electrical load increases, the current transformer can be adjusted to a higher current operating state to prevent overload damage and disruption to production. By setting up a switch 400 and adjusting the control knob 410 to change the operating state of the switch 400, the second terminal 602 can be connected to different positions on the first and second windings 200, thus changing the current ratio. Furthermore, changing the current ratio does not require disassembling or reassembling the external wiring connected to the first and second terminals 601 and 602, making it suitable for situations with limited installation space or where the transformation ratio needs to be changed quickly.

[0052] 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 inside the housing 420. The switching plate 450 has a swing end and a fixed end. The switching plate 450 is electrically connected to a fifth terminal 605, and the fixed end is rotatably connected to the housing 420 via a vertically arranged first rotating shaft 460. In a first working state, the swing end abuts against the front side of the sixth terminal 606. In a second working state, the swing end abuts against the front side of the seventh terminal 607. The switching plate 450 is linked to a control knob 410. Thus, rotating the control knob 410 causes the switching plate 450 to rotate, 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.

[0053] In some embodiments of the present invention, in a first operating state, the swing end is located at the left end of the switching plate 450, and in a second operating state, the swing end is located at the right end of the switching plate 450. The housing 420 is a component made of insulating material, see reference... Figure 5The sixth terminal 606 is located to the left of the seventh terminal 607. The sixth terminal 606 includes a horizontal part and a vertical part. The vertical part extends vertically through the top wall of the housing 420. The horizontal part extends to the right from the bottom end of the vertical part. A rearward recessed mating groove is provided on the front side of the right end of the horizontal part. The seventh terminal 607 and the sixth terminal 606 are arranged in a left-right mirror symmetrical configuration.

[0054] The spacing between the seventh terminal 607 and the sixth terminal 606 is relatively large, and the movement path of the swing end is longer when switching working states, reducing the risk of short circuit. A docking post is provided on the upper side of the swing end of the switching plate 450. The docking post is adapted to the docking groove. In the first working state, the docking post is set in the docking groove and abuts against the groove wall of the docking groove. Both the switching plate 450 and the docking post are copper or other conductive material components.

[0055] 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 housing 420.

[0056] The switching plate 450 is disposed on the rotating seat 440, and the fixed end of the switching plate 450 is fixedly disposed on the rotating seat 440. The rotating seat 440 is sleeved on the top end of the first rotating shaft 460 from top to bottom. The rotating seat 440 is provided with a cylindrical inner cavity 445 coaxial with the first rotating shaft 460. The inner cavity 445 is disposed on the upper side of the first rotating shaft 460. An annular spring is disposed inside the inner cavity 445. The switching plate 450 is electrically connected to the annular spring.

[0057] The annular spring has a first segment 441, a second segment, a third segment 443, and a fourth segment connected end to end, such that the third segment 443 tends to move away from the first segment 441. The first segment 441 is fixedly connected to the inner wall of the inner cavity 445. The switching plate 450 can be connected to the first segment 441 via a wire. The fifth terminal 605 is eccentrically located on the front side of the top end of the first rotating shaft 460. The fifth terminal 605 is located inside the inner cavity 445. The fifth terminal 605 can be connected to the second terminal 602 via a wire. The fifth terminal 605 abuts against the side of the third segment 443 away from the first segment 441.

[0058] By setting an annular spring and eccentrically positioning the fifth terminal 605, the annular spring moves within the inner cavity 445 to the side with a larger distance between the fifth terminal 605 and the inner wall of the inner cavity 445 (i.e., the rear side of the fifth terminal 605). In other words, the annular spring tends to rotate until the first segment 441 moves to the rear end of the inner cavity 445, causing the switching plate 450 to tend to swing backward. This allows the switching plate 450 to maintain contact with the seventh terminal 607 or the sixth terminal 606, ensuring good contact. At the same time, the third segment 443 of the annular spring always remains in contact with the fifth terminal 605. This achieves the goal of maintaining good contact when the switching plate 450 and the fifth terminal 605 rotate relative to each other, as well as maintaining good contact after switching between the sixth terminal 606 and the seventh terminal 607.

[0059] The ring-shaped spring can be a copper spring or other conductive spring, see reference. Figure 6 In the first working state, the annular spring is located on the left rear side of the fifth terminal 605, and the first segment 441 is fixedly disposed on the left rear wall of the inner cavity 445. The first segment 441 has a tendency to move to the right and rear, so that the switching plate 450 abuts against the sixth terminal 606; refer to Figure 7 In the second working state, the annular spring is located on the right rear side of the fifth terminal 605, and the first segment 441 is fixedly disposed on the right rear wall of the inner cavity 445. The first segment 441 has a tendency to move to the left and rear, so that the switching plate 450 abuts against the seventh terminal 607; the switching switch 400 has an intermediate state, as shown in the reference. Figure 8 In the intermediate state, the annular spring is located in front of the fifth terminal 605, and the first segment 441 is fixedly set on the front wall of the inner cavity 445. At this time, operating the adjustment knob will cause the first segment 441 to move slightly to the left, and the switch 400 will have a tendency to switch to the first working state automatically. Operating the adjustment knob will cause the first segment 441 to move slightly to the right, and the switch 400 will have a tendency to switch to the second working state automatically, which is convenient for the operator to switch.

[0060] In some embodiments of the present invention, reference is made to... Figure 4A switching plate 450 is connected to a first gear 431, and a control knob 410 is connected to a second gear 432. The second gear 432 meshes with the first gear 431, and the number of teeth on the first gear 431 is less than the number of teeth on the second gear 432. Both the second gear 432 and the first gear 431 can be insulators. The first gear 431 is fitted onto the outside of a rotating base 440, which can be an integral component with the first gear 431. The second gear 432 is positioned above the control knob 410, and 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 housing 420. Rotating the control knob 410 rotates the second gear 432, which in turn drives the first gear 431, causing the switching plate 450 to swing. By setting the first gear 432... The number of teeth on the first gear 431 is less than the number of teeth on the second gear 432. Rotating the control knob 410 by a small angle will allow the rotating seat 440 to rotate by a larger angle to complete the switching of working states, which is convenient for the operator to adjust. At the same time, after exceeding the intermediate state, the rotating seat 440 will drive the second gear 432 while rotating under the action of the ring spring. Setting the number of teeth on the first gear 431 to be less than the number of teeth on the second gear 432 can also reduce the resistance of the second gear 432 to the rotation of the rotating seat 440, so that the elastic force of the ring spring can be sufficient to drive the rotating seat 440.

[0061] In the prior art, technical skills training for current transformers usually uses the same current transformers as those used in the production site. However, these current transformers have fewer types of faults, which affects the training effect. Therefore, the second aspect of the present invention also proposes a current transformer experimental device.

[0062] The current transformer experimental apparatus of the second aspect 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 the housing body 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 wire. 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 set to simulate an insulation fault in the primary winding 100 to meet the requirements of the insulation measurement experiment of the primary winding 100. 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., grounded), thereby simulating different fault conditions and improving the training effect.

[0063] In some embodiments of the present invention, the current transformer experimental apparatus further includes a second adjustable resistor 520. The second adjustable resistor 520 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.

[0064] In this embodiment, a second adjustable resistor 520 is set to simulate a secondary winding insulation fault to meet the requirements of the secondary winding insulation measurement experiment. In addition, rotating the second adjustment knob 521 can adjust the resistance value between the first secondary winding 200 and the steel plate 020 (i.e., grounding), thereby simulating different fault conditions and improving the training effect.

[0065] In some embodiments of the present invention, reference is made to... Figure 9 The current transformer experimental device also includes a third adjustable resistor 530, which includes a third adjustment knob 531 disposed on the steel plate 020 and a third resistor body disposed 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.

[0066] The structure of the second secondary winding 300 is the same as that of the first secondary winding 200, that is, the second secondary winding 300 also includes a support ring, an iron core, and a secondary coil. The surface of the shell body 010 is provided with a third terminal 603 and a fourth terminal 604. One end of the secondary coil of the second secondary winding 300 is connected to the third terminal 603 through a flexible wire, and the other end of the secondary coil of the second secondary winding 300 is connected to the fourth terminal 604 through 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 through a flexible wire. The third adjustment knob 531 is used to control the resistance value of the third adjustable resistor 530. In this embodiment, the third adjustable resistor 530 is set to simulate the insulation fault between the primary winding 100 and the secondary winding. Rotating the third adjustment knob 531 can adjust the resistance value between the primary winding 100 and the secondary winding, thereby simulating different fault conditions, which is beneficial to improving the training effect.

[0067] The first, second, and third adjustable insulation resistors can all be conventional rotary adjustable resistors, such as potentiometers, and their specific structures will not be described in detail here. The first adjustment knob 511, the second adjustment knob 521, and the third adjustment knob 531 are all provided with a cross-shaped or flat slot for easy rotation with a screwdriver. The first adjustment knob 511, the second adjustment knob 521, the third adjustment knob 531, and the control knob 410 are all rotatably embedded in the lower surface of the steel plate 020 and flush with it for stable placement. Each knob has an indicator arrow on the lower surface of the steel plate 020.

[0068] The current transformer experimental device of this invention, by setting a first adjustable resistor 510, a second adjustable resistor 520, and a third adjustable resistor 530, can conveniently simulate grounding faults in the primary winding 100, grounding faults in the secondary winding, and insulation faults in both primary and secondary windings. This ensures that trainees can safely and conveniently access a sufficient number of faults during the teaching process and apply them, effectively reducing the problem of limited fault types in existing teaching methods and significantly improving the training effect. Furthermore, the switch 400, while ensuring safety and convenience, allows trainees to access and understand faults such as short circuits caused by coil adhesion in the secondary coil, further expanding the range of fault types. The main body 010 is detachably mounted on the steel plate 020 via bolts, facilitating subsequent maintenance and repair of the current transformer, reducing teaching costs, and providing a clearer demonstration of the internal structure of the current transformer to trainees. The current transformer experimental device of the present invention can be used to conduct experiments such as the insulation resistance measurement experiment of the primary coil of the current transformer, the insulation resistance measurement experiment of the secondary coil of the current transformer, the AC withstand voltage test of the current transformer, the current ratio and polarity check experiment of the current transformer, and the DC resistance measurement experiment of the current transformer winding. By configuring different coil turns and different insulation resistance values, different experimental results can be obtained, which is conducive to obtaining better training results.

[0069] The experimental method of the third aspect of the present invention uses the above-described current transformer experimental apparatus to conduct a 100Ω insulation resistance test on a primary winding. The experimental method includes the following steps:

[0070] S110, rotate the first adjustment knob 511 to any position and perform a winding insulation resistance measurement;

[0071] S120, adjust the position of the first adjustment knob 511 and perform a winding insulation resistance measurement;

[0072] S130, compare and analyze the results of two 100 insulation resistance measurements of the primary winding.

[0073] By using the aforementioned current transformer experimental apparatus, the insulation resistance value of the primary winding 100 can be adjusted during the experiment to achieve better training results. Similarly, the experimental method of the present invention can also use the aforementioned current transformer experimental apparatus to conduct insulation resistance tests on the secondary winding; it can also use the aforementioned current transformer experimental apparatus to conduct insulation resistance tests between the primary winding 100 and the secondary winding. The measurement of the insulation resistance of the primary winding 100, the insulation resistance of the secondary winding, and the insulation resistance between the primary winding 100 and the secondary winding are all conventional techniques in the art, and their specific steps will not be elaborated here.

[0074] The experimental method of the fourth aspect of the present invention uses the above-described current transformer to perform ratio and polarity experiments. The experimental method includes the following steps:

[0075] S210, adjust the switch 400 to the first working state and perform a ratio and polarity check test;

[0076] S220, adjust the switch 400 to the second working state and perform a ratio and polarity check test;

[0077] S230, compare and analyze the results of the two ratio and polarity check tests.

[0078] By setting a switching switch 400 and connecting different numbers of turns of the first and second windings 200 via the first terminal 601 and the second terminal 602, different coil turns can be configured, resulting in different experimental results and achieving better training effects. Among these, checking the ratio and polarity of the current transformer is a conventional technique in this field, and its specific steps will not be elaborated here. In addition, connecting different numbers of turns of the first and second windings 200 via the first terminal 601 and the second terminal 602 can also simulate the problem of short circuit caused by partial coil adhesion in the first and second windings. Under the premise of ensuring safety and convenience, this allows trainees to access and understand the fault caused by partial coil adhesion in the secondary winding, further improving their understanding of fault types.

[0079] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A current transformer, characterized in that, include: The outer casing includes a casing body and a steel plate disposed at the bottom of the casing body. The surface of the casing body is provided with a first terminal, a second terminal and two primary terminal blocks. The primary winding is electrically connected at both ends to two primary terminals respectively; The switch includes a main body located inside the housing and a control knob located on a steel plate. The main body has a fifth terminal, a sixth terminal, and a seventh terminal. The first and second windings have a first-turn tap, a last-turn tap, and an intermediate tap. 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 intermediate tap, and the last-turn tap, respectively. The main body includes a housing, inside which is a switching plate. The switching plate is electrically connected to the fifth terminal. The switching plate has a fixed end and a swing end. The fixed end is rotatably connected to the housing via a vertically set first rotating shaft. The control knob is linked to the switching plate. A rotating seat is rotatably sleeved on the outer side of the first rotating shaft. A switching plate is disposed on the rotating seat. The rotating seat has a cylindrical inner cavity coaxial with the first rotating shaft. An annular spring is disposed in the inner cavity. The annular spring is electrically connected to the switching plate. The annular spring has a first segment, a second segment, a third segment, and a fourth segment connected end to end, such that the third segment tends to move away from the first segment. The first segment is fixedly connected to the inner wall of the inner cavity. The fifth terminal is eccentrically disposed on the front side of the top end of the first rotating shaft. The fifth terminal abuts against the side of the third segment away from the first segment. The switch has a first working state and a second working state. In the first working state, the swing end is located at the left end of the switching plate, the annular spring is located at the left rear side of the fifth terminal, the first section is fixedly set on the left rear wall of the inner cavity, the first section has a tendency to move to the right and rear, the swing end abuts against the front side of the sixth terminal, and the fifth terminal and the sixth terminal are electrically connected. In the second working state, the swing end is located at the right end of the switching plate, the annular spring is located at the right rear side of the fifth terminal, the first section is fixedly set on the right rear wall of the inner cavity, the first section has a tendency to move to the left and rear, the swing end abuts against the front side of the seventh terminal, and the fifth terminal and the seventh terminal are electrically connected.

2. The current transformer according to claim 1, characterized in that: The switching plate is connected to a first gear, and the control knob is connected to a second gear. The first gear meshes with the second gear, and the number of teeth on the first gear is less than the number of teeth on the second gear.

3. An experimental apparatus for a current transformer, characterized in that: It includes a first adjustable resistor and a current transformer as described in claim 1 or 2. The first adjustable resistor includes a first resistor body disposed within the housing body and a first adjustment knob disposed on the steel plate. The first adjustable resistor is electrically connected between the primary winding and the steel plate.

4. The current transformer experimental apparatus according to claim 3, characterized in that: It also includes a second adjustable resistor, which includes a second resistor body disposed within the housing body and a second adjustment knob disposed on the steel plate. The second adjustable resistor is electrically connected between the first secondary winding and the steel plate.

5. The current transformer experimental apparatus according to claim 3, characterized in that: It also includes a third adjustable resistor, which includes a third resistor body disposed within the housing body and a third adjustment knob disposed 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.

6. An experimental method, characterized in that: A primary winding insulation resistance test is performed using the current transformer experimental apparatus as described in claim 3, the experimental method comprising the following steps: Rotate the first adjustment knob to any position and perform a winding insulation resistance measurement; Adjust the position of the first adjustment knob and perform a winding insulation resistance measurement; The results of two measurements of the insulation resistance of the primary winding were compared and analyzed.

7. An experimental method, characterized in that: The current transformer as described in claim 1 or 2 is used to perform a ratio and polarity experiment, the experimental method comprising the following steps: Adjust the switching switch to the first working state and perform a ratio and polarity check test; Adjust the switching switch to the second working state and perform a ratio and polarity check test; The results of the two ratio and polarity check tests were compared and analyzed.

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