Lead loop impedance abnormity monitoring and positioning device and method for mutual inductor detection

Abstract

The invention discloses a lead loop impedance abnormity monitoring and positioning device and method for mutual inductor detection, and relates to the technical field of mutual inductor detection. The traditional method has the problem of lag in the abnormal detection of the mutual inductor. The device comprises two voltage measurement modules which need to be matched with a current transformer detection device comprising a primary wire, a sliding base, a primary wire crimping mechanism, a fixed rack, a primary wire outgoing line, a secondary connection mechanism and a secondary wire outgoing line, and the primary wire outgoing line is connected with a current booster and a standard device. And the secondary lead outgoing line is respectively connected with a secondary load and a calibrator. According to the method, the characteristic that the impedances of the two crimping parts of the primary wire are basically equal is utilized, sudden primary loop impedance abnormity is detected more sensitively, monitoring and positioning of the loop impedance abnormity are completed through the relation between the impedance abnormity and the branch voltage, and therefore the impedance of the secondary loop is calculated on the premise that the secondary loop voltage is not directly measured, and the reliability of the secondary loop is improved. And the detection of the impedance abnormity on the secondary loop is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer detection, and particularly to a device and method for monitoring and locating abnormal impedance of a wire loop for transformer detection. Background Art

[0002] In a low-voltage AC distribution network, it is relatively difficult to directly measure large currents. The rated current of ordinary installed watt-hour meters generally does not exceed 100A. Therefore, a special transformer is commonly used to convert large currents into small currents, and the conversion device used is called a current transformer. The advantages of using a transformer are that it isolates the measuring instrument from high voltage, ensuring the safety of the instrument and personnel; it can expand the measuring range of the instrument, facilitating the standardization of the instrument; and it can also reduce the energy consumption in measurement. Therefore, the application of transformers is quite extensive. For large-current users with low-voltage power supply exceeding 100A, it is an inevitable choice to use a low-voltage current transformer to expand the metering range of the watt-hour meter.

[0003] The electric energy metering device of large users is related to the interests of both power supply companies and users. If the transformer becomes inaccurate, it will cause great losses to the power supply company or users. Therefore, to ensure accurate metering, it is necessary to conduct pre-installation inspection on whether the transformer is inaccurate. During the inspection, the transformer needs to be connected in series to the primary and secondary circuits. Therefore, a section of conductor (referred to as the primary conductor) in the primary circuit needs to be frequently disconnected / connected from the circuit, and at the same time, the secondary circuit also needs to be repeatedly disconnected / connected to measure the secondary winding of the transformer by methods such as crimping a copper bar and clamping the secondary terminal of the transformer to be measured with an alligator clip. The above methods have the risk of introducing abnormal contact impedance due to poor contact.

[0004] In addition, since the primary currents of different specifications of transformers are different, the wire diameters required for the primary conductors used to be connected in series to the transformers vary greatly. Generally, multiple specifications of primary conductors are prepared. The contact between the primary conductor and the crimping mechanism is exposed to the air for a long time when not in use, and is under the influence of large mechanical stress and thermal stress during testing, accelerating the corrosion rate, which further exacerbates the risk of abnormal contact impedance.

[0005] If the impedance of the primary circuit increases abnormally, it will not only increase the heat generation, but also the maximum output power required by the current booster may exceed the load-carrying capacity of the current booster, causing the output current waveform to be severely distorted, resulting in a decrease in metering accuracy. An abnormal increase in the impedance of the secondary circuit will increase the error of the transformer.

[0006] When existing current transformers are calibrated or verified manually or automatically, in order to monitor the impedance abnormality of the primary circuit and the abnormal temperature rise caused thereby, it is necessary to add temperature sensors at locations where large impedance may occur (such as the crimping points of primary conductors) to monitor the temperature rise in real time, and take appropriate countermeasures when the temperature rise exceeds the threshold. At present, there is no mature monitoring method for the abnormal increase in the impedance of the secondary circuit, and it can only be detected when the impedance abnormality degree is too high, such as when the crimped copper bar is completely not in contact with the secondary terminal of the current transformer to be measured, resulting in no current flowing through the secondary side.

[0007] Therefore, the temperature sensor detection method can only detect the abnormal resistance of the primary circuit near the temperature sensor, and has no detection ability for the impedance abnormality on the secondary circuit. It is difficult to control the sensitivity of the temperature sensor detection method. If the threshold is set too large, it is easy to cause the failure to detect impedance abnormalities with low amplitudes. If the threshold is set too small, it is easy to cause false alarms. Summary of the Invention

[0008] The technical problem to be solved and the technical task proposed by the present invention are to improve and refine the existing technical solution, and provide a device and method for monitoring and positioning the impedance abnormality of the wire circuit for current transformer detection, so as to achieve the purpose of detecting the impedance abnormality on the secondary circuit. To this end, the present invention adopts the following technical solutions.

[0009] Device for monitoring and locating abnormal impedance of wire loop for current transformer detection, comprising two voltage measurement modules, which cooperate with the current transformer detection device. The current transformer detection device includes a primary wire, a sliding base, a primary wire crimping mechanism, a fixed frame, a primary wire outlet, a secondary connection mechanism and a secondary wire outlet. The primary wire is arranged on the sliding base. The fixed frame includes a back plate and a bottom plate. There are 2 sets of the primary wire crimping mechanisms, which are respectively arranged at the left and right ends on the upper surface of the bottom plate of the fixed frame. The sliding base can slide back and forth to move the two ends of the primary wire into the primary wire crimping mechanism for crimping and fixing. The 2 sets of the primary wire crimping mechanisms are provided with primary wire outlet ports. The 2 primary wire outlet ports are respectively connected to a current booster and a standard device through the primary wire outlet. The secondary connection mechanism is arranged on the back plate of the fixed frame. The secondary connection mechanism is respectively connected to a secondary load and a calibrator through the secondary wire outlet. One voltage measurement module is connected between each of the 2 primary wire outlet ports and the voltage reference point in the middle of the primary wire. During operation, the current transformer is connected in series to the primary wire, then the sliding base moves, and the primary wire moves so that its two ends slide into the primary wire crimping mechanism for crimping contact to complete the conduction of the primary loop. The secondary connection mechanism crimps the secondary winding of the current transformer to complete the conduction of the secondary loop. This device can more sensitively detect sudden abnormal impedance of the primary loop by using the characteristic that the impedances of the two crimping points of the primary wire are basically equivalent, and can complete the monitoring and location of the abnormal loop impedance by using the relationship between the abnormal impedance and the branch voltage, so as to calculate the impedance of the secondary loop without directly measuring the voltage of the secondary loop, and realize the detection of abnormal impedance on the secondary loop.

[0010] As a preferred technical means: The primary wire adopts a plurality of combinable group wire conductive bars. The group wire is carried out according to the combined number of the group wire conductive bars required for the cross-section of the primary wire, avoiding the situation that traditional primary wires need to frequently select wires, and there is no need to prepare primary wires of different specifications, avoiding waste of resources and simplifying the operation.

[0011] As a preferred technical means: A group wire platform is arranged in the middle of the sliding base. The left and right middle parts of the primary wire are arranged on the group wire platform. The upper end surface of the group wire platform and the lower end surface of the crimping groove of the primary wire crimping mechanism are at the same horizontal height. The three points at the same height can stably place the primary wire and are also convenient for the movement and crimping of the primary wire.

[0012] As a preferred technical means: The wire grouping platform is provided with a plurality of vertical wire grouping screws. The wire grouping screws penetrate upward through the wire grouping platform and are matched with the vertically penetrating threaded holes provided on the wire grouping conductive bars. The wire grouping screws are connected to a driving motor through a transmission mechanism. By connecting the wire grouping conductive bars in series with the wire grouping screws, a combined wire with a larger cross-section is formed, which can conveniently realize primary wires of various cross-section specifications to adapt to current transformers of different specifications. At the same time, it can cooperate with the wire feeder and the driving motor to drive, and can realize automatic wire grouping, making wire grouping more convenient.

[0013] As a preferred technical means: The two voltage measurement modules are respectively arranged under the sliding bases on both sides of the wire grouping platform. The two voltage measurement modules are connected by a left-right connecting wire. The connecting wire is provided with a front-back fixing part at the wire grouping platform. The fixing part passes through the reference hole of the wire grouping platform and protrudes forward as the voltage reference point. The fixing part is in contact conduction with the wire grouping screw, and the two voltage measurement modules are respectively in conduction with the primary wire outlet ports on both sides. The connection of the two voltage measurement modules on the primary side is realized.

[0014] As a preferred technical means: The secondary connection mechanism is provided with a crimping copper bar for crimping to the secondary winding of the current transformer. A spring is provided on the crimping copper bar. The secondary wire outlet is arranged on the back plate of the fixed frame. When the crimping copper bar elastically presses the secondary winding of the current transformer, the crimping copper bar is in conduction with the secondary wire outlet. The crimping and opening of the secondary winding of the current transformer are realized.

[0015] As a preferred technical means: The secondary connection mechanism can move vertically and is driven by a driving motor. By driving the secondary connection mechanism to move vertically, the on-off of the secondary circuit is realized, and the automatic on-off control of the secondary circuit can be realized.

[0016] As a preferred technical means: There are 2 sets of the secondary connection mechanisms, which are respectively arranged on the left and right parts of the back plate of the fixed frame. Each secondary connection mechanism is provided with multiple groups of crimping copper bars. It can effectively perform the calibration crimping of more current transformers at the same time.

[0017] As a preferred technical means: The primary wire crimping mechanism and the wire grouping platform are both made of insulating materials, and the surface of the wire grouping conductive bar is provided with an antioxidant layer. Using insulating materials can avoid the leakage of primary wires and effectively improve safety. Since the wire grouping conductive bar is in electrical contact with other structures, the surface is prone to oxidation. The antioxidant treatment on the surface can effectively prevent the contact surface from oxidation.

[0018] The working method of the wire loop impedance abnormality monitoring and positioning device for current transformer detection includes the following steps: 1) String the current transformer into the primary wire, slide the primary wire into the primary wire crimping mechanism, complete the contact crimping of the primary circuit, and connect the secondary circuit; 2) Control the up-current generator to output the i th current measurement point specified in the verification regulation, denoted as I i ; 3) When all the current transformers under test are short-circuited, the voltage measurement module calculates the left and right initial impedances respectively Z l i_0 = U li_0 / I i , Z r i_0 = U ri_0 / I i ; U li_0 , U ri_0 are the measured voltage values output by the left and right voltage measurement modules when the current I i passes through; 4) Judge according to the following formula Z l i_0 , Z r i_0 whether it exceeds the threshold value. If it is satisfied, go to the next step; otherwise, go to step 6):

[0019] In the formula: Z refi is the impedance reference value at the primary wire crimping point; ε is the calculation margin, generally taken as 0.1 - 1; 5) Judge whether Z l i_0 > Z r i_0 holds. If it holds, output that the impedance at the left crimping point of the primary wire is abnormal; otherwise, output that the impedance at the right crimping point of the primary wire is abnormal; 6) After entering the error detection, when the j th current transformer under test is connected to the secondary measurement, record the AC voltage U i_j output by the voltage measurement module, and calculate the impedance Z i_j = U i_j / I i ; 7) Judge whether j < N t holds. If it holds, return to step 6); otherwise, execute the next step; 8) Update Zrefi : Z refi ←α( Z l i_0 + Z r i_0 ) / 2 + (1 - α) Z refi , Z refi The initial value of is the impedance reference value of the primary wire crimping point measured in advance; α is a hyperparameter for updating, generally taking values from 0.01 to 0.2; 9) Judge i < N i Whether it holds. If it holds, return to step 3); otherwise, execute the next step; 10) Calculate the impedance difference vector ΔZ caused by the connection of the left and right j th current transformers, as follows: lj as follows:

[0020] ; In the formula: N t represents the number of current transformers connected by one set of secondary connection mechanisms; 11) Judge whether the secondary circuit contact is good by the contact impedance difference norm. The judgment formula is:

[0021] In the formula: ||·|| represents the norm, generally taking the ∞ norm or the 2 norm. If there is a j that satisfies the above formula, output that the impedance of the secondary circuit where the jth current transformer is located is abnormal. This method uses the change in the influence of the secondary circuit on the primary circuit impedance before and after the insertion of the current transformer to indirectly reflect the secondary circuit impedance, monitors the secondary circuit impedance using the primary circuit impedance difference method, calculates the impedance of the secondary circuit without directly measuring the secondary circuit voltage, realizes the detection of impedance abnormalities on the secondary circuit, and at the same time realizes the impedance monitoring of the primary and secondary circuits without the need to add equipment to the secondary circuit.

[0022] Beneficial effects: Based on the relationship between impedance abnormality and branch voltage, and using the characteristic that the impedances of the two crimping points of the primary wire are basically equivalent, this device can more sensitively detect sudden primary circuit impedance abnormalities using the comparison method, and utilize the change in the influence of the secondary circuit on the primary circuit impedance before and after the insertion of the current transformer, so as to indirectly calculate the impedance of the secondary circuit without directly measuring the secondary circuit voltage, and realize the monitoring and positioning of impedance abnormalities in the secondary circuit. Description of the Drawings

[0023] Figure 1It is a schematic diagram of the circuit connection of the present invention.

[0024] Figure 2 It is a 3D schematic diagram of the device structure of the present invention.

[0025] Figure 3 It is a front view schematic diagram of the device structure of the present invention.

[0026] Figure 4 It is the present invention Figure 3 The enlarged schematic diagram of part A in.

[0027] Figure 5 It is a schematic diagram of the working method flow of the present invention.

[0028] In the figure: 1, primary wire; 2, sliding base; 3, primary wire crimping mechanism; 4, fixed frame; 5, primary wire outlet; 6, voltage measurement module; 7, secondary connection mechanism; 8, secondary wire outlet; 9, wire grouping platform; 10, wire grouping screw; 11, voltage reference point; 12, primary wire outlet port; 13, current transformer; 14, slide rail assembly; 101, wire grouping conductive bar; 401, back panel; 402, bottom plate; 701, crimping copper bar. Detailed implementation manners

[0029] The technical solutions of the present invention will be further described in detail below in conjunction with the accompanying drawings of the specification.

[0030] As Figures 1-3 shown, the device for monitoring and positioning abnormal impedance of the wire loop for current transformer detection includes two voltage measurement modules 6; the voltage measurement module 6 cooperates with the current transformer detection device, and the current transformer detection device includes a primary wire 1, a sliding base 2, a primary wire crimping mechanism 3, a fixed frame 4, a primary wire outlet 5, a voltage measurement module 6, a secondary connection mechanism 7 and a secondary wire outlet 8. The primary wire 1 is arranged on the sliding base 2, and the sliding base 2 is slidably connected to the fixed frame 4 through the slide rail assemblies 14 on both sides. The fixed frame 4 includes a back panel 401 and a bottom plate 402. There are 2 sets of primary wire crimping mechanisms 3, which are respectively arranged at the left and right ends on the upper surface of the bottom plate 402 of the fixed frame 4. The sliding base 2 can slide back and forth to move the two ends of the primary wire 1 into the primary wire crimping mechanism 3 for crimping and fixing. The 2 sets of primary wire crimping mechanisms 3 are provided with primary wire outlet ports 12. The two primary wire outlet ports 12 are respectively connected to a current booster and a standard device through the primary wire outlet 5. The secondary connection mechanism 7 is arranged on the back panel 401 of the fixed frame 4. The secondary connection mechanism 7 is respectively connected to a secondary load and a calibrator through the secondary wire outlet 8. A voltage measurement module 6 is connected between each of the two primary wire outlet ports 12 and the voltage reference point 11 in the middle of the primary wire 1.

[0031] To avoid waste of resources, the primary wire 1 adopts a combinable multi-strand conductive bar 101. The wires are grouped according to the number of combined conductive bars 101 required for the cross-section of the primary wire 1, avoiding the situation where traditional primary wires 1 often require wire selection and eliminating the need to prepare primary wires 1 of different specifications, thus avoiding waste of resources, simplifying the operation, and eliminating safety risks such as dropping caused by traditional manual replacement of the primary wire 1.

[0032] To facilitate the movement and crimping of the primary wire 1, a wire grouping platform 9 is provided in the middle of the sliding base 2. The middle part of the primary wire 1 in the left-right direction is arranged on the wire grouping platform 9. The upper end surface of the wire grouping platform 9 and the lower end surface of the crimping groove of the primary wire crimping mechanism 3 are at the same horizontal height. The three points being at the same horizontal height can stably place the primary wire 1 and also facilitate the movement and crimping of the primary wire 1.

[0033] To facilitate wire grouping, as Figure 4 shown, the wire grouping platform 9 is provided with a plurality of vertical wire grouping screws 10. The wire grouping screws 10 penetrate upward through the wire grouping platform 9 and match with the vertically penetrating threaded holes provided on the conductive bar 101 for wire grouping. The wire grouping screws 10 are connected to a drive motor through a transmission mechanism. The conductive bars 101 for wire grouping are connected in series through the wire grouping screws 10 to form a combined wire with a larger cross-section, enabling the convenient realization of primary wires 1 of various cross-section specifications to adapt to different specifications of current transformers 13. At the same time, it can be driven in cooperation with a wire preparation device and a drive motor. The wire preparation device is provided with wire preparation screws corresponding to the same number and position. The wire preparation screws and the wire grouping screws 10 are connected through complementary end structures. By driving the wire grouping screws 10 with the drive motor, the rotational upward movement and rotational downward movement of the wire grouping screws 10 and the wire preparation screws are realized to change the number of conductive bars 101 for wire grouping connected to the wire grouping screws 10, achieving automatic wire grouping, which is more convenient. In this example, the drive motor of the wire grouping screws 10 adopts a stepping motor.

[0034] To realize the physical connection structure of the two voltage measurement modules 6 on the primary side, the two voltage measurement modules 6 are respectively arranged under the sliding bases 2 on both sides of the wire grouping platform 9. The two voltage measurement modules 6 are connected by a left-right connecting wire. The connecting wire is provided with a front-back fixing part at the wire grouping platform 9. The fixing part penetrates forward into the front reference hole of the wire grouping platform 9 and protrudes outside as the voltage reference point 11. The fixing part is in contact conduction with the wire grouping screw 10. The two voltage measurement modules 6 are respectively in conduction with the primary wire outlet ports 12 on both sides. The physical connection structure of the two voltage measurement modules 6 on the primary side is effectively realized.

[0035] In order to achieve the crimping and opening of the secondary winding of the mutual inductor 13 by the secondary connection mechanism 7, the secondary connection mechanism 7 can move vertically and is driven by a driving motor. A crimping copper bar 701 for crimping to the secondary winding of the mutual inductor 13 is provided on the secondary connection mechanism 7, and a spring is provided on the crimping copper bar 701. The secondary wire outlet 8 is provided on the back plate 401 of the fixed frame 4. When the crimping copper bar 701 elastically presses the secondary winding of the mutual inductor 13, the crimping copper bar 701 is conducted with the secondary wire outlet 8. By driving the secondary connection mechanism 7 to move vertically through the motor, the crimping copper bar 701 is elastically pressed against and disconnected from the secondary winding of the mutual inductor 13, realizing the crimping on and off of the secondary circuit, and the automatic on and off control of the secondary circuit can be realized.

[0036] In order to simultaneously achieve the verification crimping of more mutual inductors 13, two sets of secondary connection mechanisms 7 are respectively arranged on the left and right parts of the back plate 401 of the fixed frame 4. In this example, each set of secondary connection mechanism 7 is provided with three groups of crimping copper bars 701. It can effectively carry out the verification crimping of more mutual inductors 13 simultaneously.

[0037] In order to achieve the electrical insulation performance, the primary wire crimping mechanism 3 and the wiring platform 9 are both made of insulating materials. In order to avoid the contact oxidation on the surface of the wiring conductive bar 101, an antioxidant layer is provided on the surface of the wiring conductive bar 101. Using insulating materials can avoid the leakage of the primary wire 1 and effectively improve safety. Since the wiring conductive bar 101 is in electrical contact with other structures, the surface is prone to contact oxidation, and the surface antioxidant treatment can effectively prevent the contact surface from oxidation.

[0038] As Figure 5 shown, the working method of the wire loop impedance abnormality monitoring and positioning device for mutual inductor detection includes the following steps: S1: String the mutual inductor 13 into the primary wire 1, slide the primary wire 1 into the primary wire crimping mechanism 3, complete the contact crimping of the primary circuit, and connect the secondary circuit; S2: Control the current booster to output the i th current measurement point specified in the verification regulation, denoted as I i ; S3: When all the measured mutual inductors 13 are short-circuited, the voltage measurement module 6 respectively calculates the left and right initial impedances Z l i_0 = U li_0 / I i , Z r i_0 = U ri_0 / I i ; U li_0 、U ri_0 The measured values of the voltages output by the left and right voltage measurement modules 6 when passing current I n ; S4: Judge according to the following formula Z l i_0 , Z r i_0 Whether it exceeds the threshold value. If it is satisfied, go to the next step; otherwise, go to step S6:

[0039] In the formula: Z refi Is the impedance reference value of the crimping point of the primary wire 1; ε is the calculation margin, generally taking 0.1~1; S5: Judge Z l i_0 > Z r i_0 Whether it holds. If it holds, output that the impedance of the left crimping point of the primary wire 1 is abnormal; otherwise, output that the impedance of the right crimping point of the primary wire 1 is abnormal; S6: After entering the error detection, when the j th measured mutual inductor 13 is connected to the secondary measurement, record the AC voltage U i_j output by the voltage measurement module 6, and calculate the impedance Z i_j = U i_j / I i ; S7: Judge j < N t Whether it holds. If it holds, return to step S6; otherwise, execute the next step; S8: Update Z refi : Z refi ←α( Z l i_0 + Z r i_0 ) / 2 +(1-α) Z refi , Z refi The initial value of is the impedance reference value of the crimping point of the primary wire 1 measured in advance; α is the hyperparameter for updating, generally taking 0.01~0.2; S9: Judge i < N i Whether it holds. If it holds, return to step S3; otherwise, execute the next step; S10: Calculate the impedance difference vector ΔZ caused by the connection of the j th current transformers 13 on the left and right sides. The calculation formula is as follows: lj

[0040] ; S11) Determine whether the secondary circuit connection is good by the norm of the contact impedance difference. The judgment formula is:

[0041] In the formula, ||·|| represents the norm, generally taking the ∞-norm or 2-norm. If there is a j that satisfies the above formula, it is output that the impedance of the secondary circuit where the jth current transformer 13 is located is abnormal. In the formula, N t represents the number of current transformers connected by one set of secondary connection mechanisms.

[0042] During operation, the current transformer 13 is connected in series to the primary wire 1, and then the sliding base 2 moves. The primary wire 1 moves so that both ends of it slide into the primary wire crimping mechanism 3. The primary wire crimping mechanism 3 crimps and contacts the primary wire 1 to complete the conduction of the primary circuit. The secondary connection mechanism 7 moves downward under the drive of the drive motor, so that the crimping copper bar 701 is pressed onto the secondary winding of the current transformer 13 and the secondary wire outlet 8 is conducted to complete the conduction of the secondary circuit. This device can utilize the characteristic that the impedances of the two crimping points of the primary wire 1 are basically equal to more sensitively detect sudden impedance abnormalities in the primary circuit; it can utilize the relationship between impedance abnormalities and branch voltages to complete the monitoring and positioning of circuit impedance abnormalities, so as to calculate the impedance of the secondary circuit without directly measuring the secondary circuit voltage, realize the detection of impedance abnormalities on the secondary circuit, and at the same time realize the impedance monitoring of the primary and secondary circuits without adding equipment to the secondary circuit.

[0043] In this embodiment, the busbar 101 for wiring uses a copper bar with a rectangular cross-section.

[0044] The above-described device and method for monitoring and positioning impedance abnormalities in the wire loop for current transformer detection are specific embodiments of the present invention, which have already reflected the prominent substantive features and remarkable progress of the present invention. According to actual usage needs, under the inspiration of the present invention, equivalent modifications can be made to its shape, structure, etc., and all are within the protection scope of this solution.​

Claims

1. A device for monitoring and locating abnormal impedance of a wire loop for current transformer detection, characterized in that: It includes two voltage measurement modules, which cooperate with the current transformer detection device. The current transformer detection device includes a primary wire, a sliding base, a primary wire crimping mechanism, a fixed frame, a primary wire outlet, a secondary connection mechanism and a secondary wire outlet. The primary wire is arranged on the sliding base. The fixed frame includes a backboard and a bottom plate. There are 2 sets of the primary wire crimping mechanisms, which are respectively arranged at the left and right ends on the upper surface of the bottom plate of the fixed frame. The sliding base can slide back and forth to move the two ends of the primary wire into the primary wire crimping mechanism for crimping and fixing. The 2 sets of the primary wire crimping mechanisms are provided with primary wire outlet ports. The 2 primary wire outlet ports are respectively connected to a current booster and a standard device through the primary wire outlet. The secondary connection mechanism is arranged on the backboard of the fixed frame. The secondary connection mechanism is respectively connected to a secondary load and a calibrator through the secondary wire outlet. A voltage measurement module is connected between each of the 2 primary wire outlet ports and the voltage reference point in the middle of the primary wire.

2. The wire loop impedance abnormality monitoring and positioning device for current transformer detection according to claim 1, wherein: The primary wire adopts combinable multi-strand conductive bars.

3. The wire loop impedance abnormality monitoring and positioning device for current transformer detection according to claim 2, wherein: A wire grouping platform is arranged in the middle of the sliding base. The middle part of the primary wire in the left-right direction is arranged on the wire grouping platform. The upper end surface of the wire grouping platform and the crimping groove of the primary wire crimping mechanism are at the same horizontal height.

4. The wire loop impedance anomaly monitoring and positioning device for current transformer detection according to claim 3, characterized in that: The wire grouping platform is provided with multiple vertical wire grouping screws. The wire grouping screws penetrate upward through the wire grouping platform and are matched with the vertical through threaded holes arranged on the wire grouping conductive bars. The wire grouping screws are connected to a driving motor through a transmission mechanism.

5. The wire loop impedance abnormality monitoring and positioning device for current transformer detection according to claim 4, characterized in that: The 2 voltage measurement modules are respectively arranged under the sliding base on both sides of the wire grouping platform. The 2 voltage measurement modules are connected through a left-right connecting wire. The connecting wire is provided with a front-back fixing part at the wire grouping platform. The fixing part passes through the reference hole of the wire grouping platform and protrudes forward as the voltage reference point. The fixing part is in contact conduction with the wire grouping screw. The 2 voltage measurement modules are respectively in conduction with the primary wire outlet ports on both sides.

6. The wire loop impedance abnormal monitoring and positioning device for transformer mutual inductor detection according to claim 5, characterized in that: The secondary connection mechanism is provided with a crimping copper bar for crimping to the secondary winding of the transformer. A spring is arranged on the crimping copper bar. The secondary wire outlet is arranged on the backboard of the fixed frame. When the crimping copper bar elastically presses the secondary winding of the transformer, the crimping copper bar is in conduction with the secondary wire outlet.

7. The wire loop impedance abnormality monitoring and positioning device for current transformer detection according to claim 6, characterized in that: The secondary connection mechanism can move vertically and is driven by a driving motor.

8. The wire loop impedance anomaly monitoring and positioning device for current transformer detection according to claim 7, characterized in that: There are 2 sets of the secondary connection mechanisms, which are respectively arranged at the left part and the right part of the backboard of the fixed frame. Each secondary connection mechanism is provided with multiple groups of crimping copper bars.

9. The wire loop impedance abnormality monitoring and positioning device for transformer mutual inductor detection according to claim 5, wherein: The primary wire crimping mechanism and the wire grouping platform both adopt insulating materials. The surface of the wire grouping conductive bar is provided with an antioxidant layer.

10. The working method of the wire loop impedance abnormality monitoring and positioning device for mutual inductor detection according to any one of claims 1-8, characterized in that It includes the following steps: 1) String the transformer into the primary wire, slide the primary wire into the crimping mechanism, complete the contact crimping of the primary circuit, and connect the secondary circuit; 2) Control the up-current generator to output the i th current measurement point specified in the verification regulation, denoted as I i ; 3) When all the current transformers under test are short-circuited, the voltage measurement module calculates the left and right initial impedances respectively Z l i_0 = U li_0 / I i , Z r i_0 = U ri_0 / I i ; U li_0 、 U ri_0 are the measured voltage values output by the left and right voltage measurement modules when the current I i passes through; 4) Judge according to the following formula Z l i_0 , Z r i_0 Whether it exceeds the threshold value. If it is satisfied, go to the next step; otherwise, go to step 6): Where: Z refi is the impedance reference value at the primary wire crimping point; ε is the calculation margin, generally taking 0.1 - 1; 5) Judgment Z l i_0 > Z r i_0 Is it established? If it is established, output that the impedance of the left crimping point of the primary wire is abnormal; otherwise, output that the impedance of the right crimping point of the primary wire is abnormal; 6) After entering the error detection, when the j th measured mutual inductor is connected to the secondary measurement, record the AC voltage output by the voltage measurement module U i_j , and calculate the impedance Z i_j = U i_j / I i ; 7) Judgment j < N t Is it established? If it is established, return to step 6); otherwise, execute the next step; 8) Update Z refi : Z refi ←α( Z l i_0 + Z r i_0 ) / 2 +(1-α) Z refi , Z refi The initial value of is the impedance reference value of the primary wire crimping point measured in advance; α is a hyperparameter used for updating, taking values from 0.01 to 0.2; 9) Judgment i < N i Whether it holds. If it holds, return to step 3); otherwise, perform the next step; 10) Calculate the impedance difference vector ΔZ j caused by the connection of the lj th current transformers on the left and right sides, as shown in the following formula: ； In the formula: N t represents the number of instrument transformers connected by one set of secondary connection mechanisms; 11) Judge whether the contact of the secondary circuit is good through the norm of the contact impedance difference. The judgment formula is: where: ||·|| represents the norm, generally taking the ∞ norm or the 2 norm. If there is j satisfying the above equation, then output the j secondary circuit where the k-th current transformer is located has an abnormal impedance.

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