An electric power experiment signal acquisition device with adjustable signal ratio

Abstract

The present invention discloses an electric power experimental signal acquisition device with an adjustable signal ratio, which relates to the technical field of electric power equipment. In order to solve the problem of inconvenient resistor replacement in existing electric power experimental signal acquisition, the following technical solution is proposed: comprising an electrical layer, a control layer, and an interactive layer, which are encapsulated by a housing; the electrical layer includes a ground wire, a voltage loop conductor, and a current loop conductor connected in parallel to each other; a resistor replacement module is provided on the interactive layer, the resistor replacement module includes a base plate, a pin holder, and a thick film resistor, the base plate is fixed to the housing, the pins of the thick film resistor are placed in the pin holder, and the thick film resistor is fixed by pressure applied by fixing screws, and the end of the pure copper plate in the pin holder is connected to the current loop conductor by a welded wire. The present invention improves experimental flexibility and accuracy, enhances user interaction experience, improves the safety and reliability of the device, facilitates maintenance and upgrading, and reduces experimental costs.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power equipment, and in particular to an electric power experimental signal acquisition device with adjustable signal transformation ratio. Background Art

[0002] During high-voltage fault experiments, researchers used fault recorders to collect electrical data for analysis. However, fault recorders only capture the waveform of the signal and cannot directly display the changes in the effective value of the current or voltage signal. Some recorders are even unable to observe changes in the electrical signal during the recording process and can only convert the effective value after collection. In experiments, signal changes are important information for controlling the progress of the experiment. If the current signal is about to become too large and damage the line, and the data changes in real time are visible, the power can be cut off in time before the line is damaged, and more signals can be collected for analysis while protecting the line. There are already devices similar to clamp ammeters on the market that can display the effective value of the collected secondary current signal in real time, but this type of device needs to be connected in series with the circuit and cannot be converted to the primary side. Multiple lines require multiple clamp ammeters, and they are expensive.

[0003] Commonly used voltage-based fault recorders cannot directly collect current signals. Instead, they require a suitable resistor to be connected in series with the circuit. The voltage across the resistor is then used to collect the current flowing through it. However, many resistors have short leads, so conventional methods of connecting them to the circuit can result in incomplete signal waveforms due to unstable connections. Soldering is also very cumbersome.

[0004] The transformers in the experimental platform are often fixed. The secondary side of the voltage transformer cannot be short-circuited, and the secondary side of the current transformer cannot be open-circuited. When a transformer is not in use, manual inspection of the secondary side of the transformer is required. However, there are many transformers and lines in the experimental platform, and manual inspection may lead to negligence and experimental accidents, which poses potential risks. Summary of the Invention

[0005] The purpose of the present invention is to provide an electric power experiment signal acquisition device with an adjustable signal transformation ratio, so as to solve the problem of inconvenience in replacing resistors in the existing electric power experiment signal acquisition.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A power experiment signal acquisition device with an adjustable signal transformation ratio comprises: an electrical layer arranged at the bottom of the device, a control layer arranged in the middle of the device, and an interaction layer arranged at the top of the device, wherein the device is encapsulated by a housing; the electrical layer comprises a ground wire, a voltage loop conductor, and a current loop conductor; a resistor replacement module is provided on the interaction layer, the resistor replacement module comprises a base plate, a pin holder, and a thick film resistor, wherein the base plate is fixed to the housing, the pins of the thick film resistor are placed in the pin holder, and the thick film resistor is fixed by pressure applied by fixing screws, and the ends of the pure copper plates in the pin holders are connected to the current loop conductors by welded wires.

[0008] Preferably, the control layer includes a sensor group and a control module, and the sensor group and the control module are communicatively connected.

[0009] Preferably, the interactive layer includes a label and a switch, the label is connected to the control module for communication, and content is typed into the label through the keyboard; the switch includes a voltage loop switch and a current loop switch, the switch is connected in series in the voltage loop wire and the current loop wire of the electrical layer to control the connection and disconnection of the loop; when the voltage loop switch is disconnected, the single voltage loop wire is disconnected, and when the current loop switch is disconnected, the two current loop wires are short-circuited.

[0010] Preferably, the interaction layer further includes a numerical table connected to the control module of the control layer, and the numerical table is used to display voltage or current values.

[0011] Preferably, the interaction layer also includes an interaction module, which includes a screen and a keyboard. The screen is used to display the operation process. The information typed on the keyboard converts the effective value of the secondary side signal of the mutual inductor collected by the sensor group into the primary side effective value. The effective value of the signal of the current loop is displayed through a numerical table or converted to the effective value of the primary side signal.

[0012] Preferably, the control module includes a power module, a signal conditioning circuit, a microcontroller and a keyboard control chip. The power module supplies power to the signal conditioning circuit, the microcontroller, the keyboard control chip, the sensor group, the switch, the numerical table and the interactive module. The sensor group transmits the collected voltage and current signals to the microcontroller through the signal conditioning circuit. The information typed on the keyboard is transmitted to the keyboard control chip for processing and then transmitted to the microcontroller. The microcontroller controls the numerical table, the switch and the screen.

[0013] Preferably, the upper end of the shell is provided with a wiring terminal and a ground screw column, the lower end is provided with a pure copper terminal, and a power socket is provided on the left side. The wiring terminal is connected to the pure copper terminal of the electrical layer through a voltage loop wire and a current loop wire, and the ground screw column is connected to the electrical layer through a ground wire.

[0014] Preferably, there are two pillars under the pin holder, the backs of the two pillars are fixed to the same baffle, the pillars are fixed to the bottom plate through the holes, the pin holder can move left and right, and there are long openings on both sides of the pin holder shell, which can be used to fix the pins of the metal film resistor.

[0015] Preferably, a voltage loop is also included, which includes wiring terminals, labels, switches, numerical tables, pure copper terminals and voltage loop wires. The wiring terminals are connected to the secondary side signal line of the voltage transformer, the wiring terminals and the pure copper terminals are connected through the voltage loop wires, the voltage loop switch is connected in series in the voltage loop, and the sensor group detects the voltage value between the voltage loop wires and the ground wire.

[0016] Preferably, it also includes a current loop, which includes wiring terminals, labels, switches, numerical tables, resistance replacement modules, pure copper terminals and current loop wires. The wiring terminals are connected to the secondary side signal lines of the current transformer, the wiring terminals and the pure copper terminals are connected through the current loop wires, the current loop switch is connected in series in the current loop, the sensor group detects the current value in the current loop, and the end of the current loop wire is connected to the end wire of the pure copper plate.

[0017] The present invention has the following beneficial effects:

[0018] Convenient resistor replacement: The device is designed with a resistor replacement module, allowing users to easily replace resistor elements to adapt to different experimental needs. This feature not only increases experimental flexibility but also reduces the complexity and time cost of replacing resistors.

[0019] Improved experimental flexibility and accuracy: The device features an adjustable signal ratio, easily adapting to power signal acquisition requirements at varying voltage or current levels, enhancing experimental flexibility. The high-precision sensor array and control module ensure precise conditioning and processing of the acquired signals, improving experimental accuracy.

[0020] Enhanced user interaction experience: The interactive layer is designed with user needs in mind. Components such as labels, switches, value tables, and interactive modules provide an intuitive and convenient interface. Users can enter information via the keyboard to convert sensor signals to RMS values. The value table displays the current loop's RMS value or the converted primary signal's RMS value in real time. This design not only improves user efficiency but also reduces operational complexity.

[0021] Improved device safety and reliability: Reasonable electrical connections and signal transmission methods ensure stable operation between components. Safety measures such as grounding, voltage loops, and current loops effectively prevent electrical faults and short circuits.

[0022] Easy maintenance and upgrade: Reasonable housing design and modular components make maintenance and upgrade operations easy for users. Users can add or replace other functional modules as needed to expand the function and application range of the device.

[0023] Reduced experimental costs: By designing components such as adjustable signal ratios and replaceable resistors, the device can collect and analyze a variety of signals, eliminating the additional costs associated with replacing different acquisition devices. High-precision components and efficient experimental processes reduce overall experimental costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a front structural diagram of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0025] Figure 2 This is a diagram of the electrical layer structure of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0026] Figure 3 This is a structural diagram of the control layer of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0027] Figure 4 This is a diagram of the interactive layer structure of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0028] Figure 5 This is a structural diagram of the housing of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0029] Figure 6 This is a left side view of the voltage circuit of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0030] Figure 7 This is a left side view of the current loop of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0031] Figure 8 A schematic diagram of the switches of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0032] Figure 9 This is a structural diagram of thick film resistors and metal film resistors in the power experiment signal acquisition device with adjustable signal ratio of the present invention;

[0033] Figure 10 This is a structural diagram of a resistance replacement module of an electric power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0034] Figure 11 This is a left side view of the resistance replacement module of the power experiment signal acquisition device with adjustable signal transformation ratio according to the present invention;

[0035] Figure 12 This is a structural diagram of the pin holder of the power experiment signal acquisition device with adjustable signal transformation ratio of the present invention.

[0036] The reference numerals shown in the figure represent: 1-electrical layer, 11-ground wire, 12-voltage loop wire, 13-current loop wire, 2-control layer, 21-sensor group, 22-control module, 221-power module, 222-signal conditioning circuit, 223-microcontroller, 224-keyboard control chip, 3-interaction layer, 31-label, 32-switch, 321-voltage loop switch, 322-current loop switch, 33-value table, 34-interaction module, 341-screen, 342-keyboard, 35-resistance replacement Module, 351-base plate, 3511-hole, 3512-bolt, 352-fixer, 3521-pillar, 3522-baffle, 3523-pure copper plate, 3524-fixing screw, 3525-wire, 3526-opening, 353-top cover, 354-thick film resistor, 355-metal film resistor, 4-housing, 41-terminal block, 411-screw, 412-signal wire, 42-screw column, 421-nut, 43-pure copper terminal, 44-power socket, 5-voltage loop, 6-current loop. DETAILED DESCRIPTION

[0037] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0038] Please refer to Figure 1 The present invention relates to a power experiment signal acquisition device with an adjustable signal ratio, aiming to provide a device that can flexibly adjust the signal ratio and facilitate experimenters to conduct power experiments. The following is a detailed description of the specific embodiments of the present invention.

[0039] Please refer to Figure 2-4 First, the power experiment signal acquisition device of the present invention is structurally divided into an electrical layer 1, a control layer 2, and an interaction layer 3. These three layers are stacked from bottom to top and encapsulated within a housing 4. Electrical layer 1 is the foundation of the device and includes a ground wire 11, a voltage loop conductor 12, and a current loop conductor 13. These three are connected in parallel and together form the signal transmission path. Ground wire 11 provides a zero potential reference, voltage loop conductor 12 transmits voltage signals, and current loop conductor 13 transmits current signals.

[0040] Please refer to Figure 2The wires in electrical layer 1 are connected to external devices via terminals 41. Terminals 41 are fixed to the upper end of housing 4 and provide easy access to the signal wires on the secondary side of the transformer. The voltage loop wire 12 and current loop wire 13 are connected to the secondary sides of the voltage transformer and current transformer, respectively, via terminals 41. Meanwhile, the ground wire 11 is connected to electrical layer 1 via ground screw 42, providing grounding protection for the entire device.

[0041] At the bottom of the electrical layer 1 are pure copper terminals 43, fixed to the lower end of the housing 4. These terminals are used to connect to signal lines from external devices such as fault recorders to collect voltage signals. Each voltage circuit is assigned one terminal 41, and each current circuit is assigned two terminals 41 to receive voltage and current signals, respectively.

[0042] Please refer to Figure 3 The control layer 2 is located above the electrical layer 1 and includes a sensor group 21 and a control module 22. The sensor group 21 includes multiple sensors for detecting the voltage between the voltage loop conductor 12 and the ground wire 11, as well as the current in the current loop 6. The sensor group 21 is in communication with the control module 22, transmitting the collected signals to the control module 22 for processing.

[0043] The control module 22 is the core component of the device and includes a power module 221, a signal conditioning circuit 222, a microcontroller 223, and a keyboard control chip 224. The power module 221 provides power to the entire device, including components such as the signal conditioning circuit 222, the microcontroller 223, the keyboard control chip 224, the sensor group 21, the switch 32, the numerical table 33, the screen 341, and the keyboard 342. The signal conditioning circuit 222 pre-processes the signals collected by the sensor group 21 to improve their accuracy and stability.

[0044] The microcontroller 223 is the brains of the control module 22, responsible for receiving, processing, and analyzing signals collected by the sensor group 21. It also controls the display and operation of the numerical meter 33, switches 32, and screen 341. The keyboard control chip 224 processes information entered via the keyboard 342 and transmits it to the microcontroller 223 for further processing.

[0045] Please refer to Figure 4 The interaction layer 3, located at the top of the device, serves as the interface for experimenters to interact with the device. It includes multiple labels 31, switches 32, a numerical table 33, an interaction module 34, and a resistance change module 35. Labels 31 identify different circuits, making them easier for experimenters to identify and operate. Switches 32, connected in series between the voltage loop conductor 12 and the current loop conductor 13 of the electrical layer 1, control the connection and disconnection of the circuits.

[0046] Numerical table 33 is connected to control module 22 of control layer 2 and displays the current circuit voltage or current value. Experimenters can understand the circuit signal status by observing the values ​​on numerical table 33. Interactive module 34 includes screen 341 and keyboard 342. Screen 341 displays the operation flow and prompts, helping the experimenter understand the device's operating status and operation steps. Keyboard 342 is used to enter experimental parameters and instructions to control the device's operating status.

[0047] Please refer to Figure 10-12 The resistor replacement module 35 is a key innovation of this invention. It comprises a base plate 351, a pin holder 352, a top cover 353, and thick-film resistors 354. The base plate 351 is fixed to the housing 4, and the pin holder 352 is mounted on the base plate 351. Below the pin holder 352 are two struts 3521, the backs of which are fixed to the same baffle 3522. The struts 3521 pass through holes 3511 in the base plate 351, allowing the pin holder 352 to move left and right to accommodate resistors of different sizes.

[0048] The pin holder 352 has two pure copper plates 3523 placed one above the other, with screws 3524 located above the plates. After the pins of the thick film resistor 354 are placed in the pin holder 352, the pressure applied by the screws 3524 secures the pins to the pure copper plates 3523. The ends of the pure copper plates 3523 are connected to the current loop conductors 13 via soldered wires 3525, thereby connecting the resistor to the current loop. The pin holder 352 has long openings 3526 on both sides of its housing for securing the pins of the metal film resistor 355. After replacing the resistor, the transparent cover 353 can be replaced to protect the resistor and the pin holder 352.

[0049] In the specific implementation process, the experimenter can select a suitable thick film resistor 354 according to the experimental needs and install it in the resistor replacement module 35. By adjusting the resistance value of the resistor, the signal ratio in the current loop can be changed, thereby achieving flexible adjustment of the signal.

[0050] Please refer to Figure 6-7 In addition, the present invention also provides specific implementations of the voltage loop 5 and the current loop 6. The voltage loop 5 includes a terminal 41, a label 31, a switch 32, a numerical table 33, a pure copper terminal 43, and a voltage loop conductor 12. The secondary side signal line of the voltage transformer is connected to the voltage loop 5 through the terminal 41, and the terminal 41 and the pure copper terminal 43 are connected through the voltage loop conductor 12. The voltage loop switch 321 is connected in series in the voltage loop 5 to control the connection and disconnection of the voltage loop. The sensor group 21 detects the voltage value between the voltage loop conductor 12 and the ground wire 11, and transmits the signal to the control module 22 for processing.

[0051] The current loop 6 includes a terminal block 41, a label 31, a switch 32, a numerical table 33, a resistor replacement module 35, a pure copper terminal 43, and a current loop conductor 13. The current transformer's secondary signal line is connected to the current loop 6 via the terminal block 41. The terminal block 41 and the pure copper terminal 43 are connected via the current loop conductor 13. The current loop switch 322 is connected in series within the current loop 6 to control the connection and disconnection of the current loop. The sensor group 21 detects the current value in the current loop 6 and transmits the signal to the control module 22 for processing. Simultaneously, the end of the current loop conductor 13 is connected to the end conductor 3525 of the pure copper plate 3523, connecting the resistor to the current loop.

[0052] During use, the experimenter can observe the values ​​on the value meter 33 to understand the signal status of the current circuit. Furthermore, the experimenter can use the keyboard 342 of the interactive module 34 to enter experimental parameters and instructions to adjust the device's operating state. For example, the experimenter can use keyboard 342 to adjust the multiple of a specific circuit so that the values ​​displayed on the value meter 33 reflect the actual voltage and current values ​​on the primary side of the transformer.

[0053] Furthermore, the present invention takes into account the safety of experimenters and the protection of equipment. When the device is not powered on, all switches 32 are in the off state. After the device is powered on, the experimenter can manually operate the switches 32 to connect or disconnect the circuit as needed. The device also has an indicator light to indicate the on and off status of the switches 32. When the indicator light is green, the circuit is connected; when the indicator light is red, the circuit is disconnected.

[0054] Please refer to Figure 8 In the off state, the present invention defaults to short-circuiting the current loop and disconnecting the voltage loop to protect the safety of the experimenter. When the current loop switch 322 is disconnected, the two current loop wires 13 are short-circuited to prevent damage to the device caused by excessive current. When the voltage loop switch 321 is disconnected, the single voltage loop wire 12 is disconnected to prevent damage to the device caused by excessive voltage.

[0055] The power experiment signal acquisition device of the present invention integrates multiple signal lines into a single device, making operation more convenient and simple. Furthermore, the design of the resistor replacement module 35 and the interaction module 34 enables flexible signal adjustment and intelligent control. This enables experimenters to conduct power experiments more accurately, improving experimental efficiency and accuracy.

[0056] During the specific implementation process, the experimenters can follow the steps below:

[0057] First, insert the high-potential signal wire on the secondary side of the voltage transformer into the wiring terminal 41 of the voltage loop 5 and secure it with screws 411. Then, insert the two signal wires on the secondary side of the current transformer into the two wiring terminals 41 of the current loop 6 and secure them with screws 411.

[0058] Next, secure the grounding wire to screw post 42 via nut 421 to provide grounding protection for the entire device. Next, select an appropriate thick-film resistor 354 based on the experimental requirements and install it in the resistor replacement module 35. After replacing the transparent protective cover, connect the power supply, and the device automatically powers on.

[0059] After the device is powered on, the experimenter can view the operating procedures and prompt information on the screen 341 of the interactive module 34. Then, they click the switch 32 of the desired circuit. When the indicator light turns green, it indicates that the circuit is connected. At this point, the experimenter can observe the values ​​on the value meter 33 to understand the signal status of the current circuit.

[0060] If adjustments are needed for a particular circuit's signal, the experimenter can enter the adjustment parameters using keyboard 342 of interactive module 34. For example, they can enter a multiplier for adjusting a circuit so that the values ​​displayed on value table 33 reflect the actual voltage and current values ​​on the primary side of the transformer. This allows the experimenter to conduct power experiments more accurately and obtain the required experimental data.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A power experiment signal acquisition device with adjustable signal ratio, characterized in that: include: An electrical layer (1) is provided at the bottom of the device, a control layer (2) is provided in the middle of the device, and an interaction layer (3) is provided at the top of the device, and the device is encapsulated by a housing (4); the electrical layer (1) includes a ground wire (11), a voltage loop conductor (12), and a current loop conductor (13); The interactive layer (3) is provided with a resistor replacement module (35), the resistor replacement module (35) comprising a base plate (351), a pin holder (352) and a thick film resistor (354), the base plate (351) being fixed on the housing (4), the pins of the thick film resistor (354) being placed in the pin holder (352), and the thick film resistor (354) being fixed by pressure applied by fixing screws (3524), and the end of the pure copper plate (3523) in the pin holder (352) being connected to the current loop wire (13) by a welded wire (3525); the interactive layer (3) comprises A label (31) and a switch (32), wherein the label (31) is communicatively connected to the control module (22), and content is typed into the label (31) via a keyboard (342); the switch (32) comprises a voltage loop switch (321) and a current loop switch (322), and the switch (32) is connected in series to the voltage loop wire (12) and the current loop wire (13) of the electrical layer (1) to control the connection and disconnection of the loop; when the voltage loop switch (321) is disconnected, the single voltage loop wire (12) is disconnected, and when the current loop switch (322) is disconnected, the two current loop wires (13) are short-circuited; The interaction layer (3) further includes a numerical table (33), the numerical table (33) being connected to the control module (22) of the control layer (2), and the numerical table (33) being used to display voltage or current values; The interaction layer (3) further includes an interaction module (34), the interaction module (34) including a screen (341) and a keyboard (342), the screen (341) being used to display an operation process, and the information entered through the keyboard (342) is used to convert the effective value of the secondary side signal of the mutual inductor collected by the sensor group (21) into the effective value of the primary side, and the effective value of the signal of the current loop or the effective value converted to the primary side signal is displayed through the value table (33).

2. The power experiment signal acquisition device with adjustable signal ratio according to claim 1, characterized in that: The control layer (2) comprises a sensor group (21) and a control module (22), and the sensor group (21) and the control module (22) are communicatively connected.

3. The power experiment signal acquisition device with adjustable signal ratio according to claim 1, characterized in that: The control module (22) includes a power module (221), a signal conditioning circuit (222), a microcontroller (223) and a keyboard control chip (224). The power module (221) supplies power to the signal conditioning circuit (222), the microcontroller (223), the keyboard control chip (224), the sensor group (21), the switch (32), the numerical table (33) and the interactive module (34). The sensor group (21) transmits the collected voltage and current signals to the microcontroller (223) through the signal conditioning circuit (222). The information typed on the keyboard (342) is transmitted to the keyboard control chip (224) for processing and then transmitted to the microcontroller (223). The microcontroller (223) controls the numerical table (33), the switch (32) and the screen (341).

4. The power experiment signal acquisition device with adjustable signal ratio according to claim 1, characterized in that: The upper end of the housing (4) is provided with a wiring terminal (41) and a ground screw column (42), the lower end is provided with a pure copper terminal (43), and the left side is provided with a power socket (44), the wiring terminal (41) is connected to the pure copper terminal (43) of the electrical layer (1) through a voltage loop conductor (12) and a current loop conductor (13), and the ground screw column (42) is connected to the electrical layer (1) through a ground wire (11).

5. The power experiment signal acquisition device with adjustable signal ratio according to claim 1, characterized in that: There are two pillars (3521) below the pin holder (352), and the backs of the two pillars (3521) are fixed to the same baffle (3522). The pillars (3521) pass through the holes (3511) and are fixed to the bottom plate (351). The pin holder (352) can move left and right. There are long openings (3526) on both sides of the pin holder (352) shell, which can be used to fix the pins of the metal film resistor (355).

6. The power experiment signal acquisition device with adjustable signal ratio according to claim 3, characterized in that: The device further comprises a voltage loop (5), wherein the voltage loop (5) comprises a wiring terminal (41), a label (31), a switch (32), a numerical table (33), a pure copper terminal (43) and a voltage loop conductor (12), wherein the wiring terminal (41) is connected to a secondary side signal line of a voltage transformer, the wiring terminal (41) and the pure copper terminal (43) are connected via a voltage loop conductor (12), the voltage loop switch (321) is connected in series in the voltage loop (5), and the sensor group (21) detects a voltage value between the voltage loop conductor (12) and the ground wire (11).

7. The power experiment signal acquisition device with adjustable signal ratio according to claim 3, characterized in that: The device further comprises a current loop (6), wherein the current loop (6) comprises a wiring terminal (41), a label (31), a switch (32), a numerical table (33), a resistance replacement module (35), a pure copper terminal (43) and a current loop conductor (13), wherein the wiring terminal (41) is connected to a secondary side signal line of a current transformer, the wiring terminal (41) and the pure copper terminal (43) are connected via a current loop conductor (13), the current loop switch (322) is connected in series in the current loop (6), the sensor group (21) detects a current value in the current loop (6), and the end of the current loop conductor (13) is connected to an end conductor (3525) of the pure copper plate (3523).

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