Current transformer signal sampling and detecting device and method

Abstract

The invention provides a current transformer signal sampling and detecting device and method, and belongs to the technical field of current transformer detection. The current transformer signal sampling and detecting device comprises a current transformer and sampling equipment. A detection module provides a first voltage signal for a sampling resistor when a primary module is in a first preset state, the detection module stops providing the first voltage signal for the sampling resistor when a sampling module collects a second detection signal, and the primary module accesses current when the detection module stops providing the first voltage signal for the sampling resistor. The sampling module performs metering work when the primary module accesses current, no mutual inductor needs to be added, and the cost increased by the detection module is far lower than the cost generated by adding the function of the mutual inductor; the number of three-wire system interfaces is increased by 1.5 times under the same interface space; the circuit production process (reflow soldering) is higher than the production process (manual soldering) with the mutual inductor function, and the equipment reliability is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of current transformer detection, and in particular to a current transformer signal sampling and detection device and method. Background Art

[0002] In the existing current transformer detection scheme, a functional design is added to the current transformer, see Figure 3 A sense resistor is added to the secondary output of the current transformer. One end of the sense resistor is connected to the negative secondary output, and the other end is the sense output signal. The transformer is connected to the device via three wires: the positive secondary output, the negative secondary output, and the sense output signal. A sampling resistor is added between the positive and negative secondary outputs on the device side. When there is a current signal on the primary side, the secondary induced current is converted into a voltage signal through the sampling resistor and enters the ADC chip for sampling and measurement. The device's MCU provides a voltage signal through a voltage divider resistor via an IO port. After passing through the sense resistor, a detection signal is generated and enters the MCU's ADC sampling channel. The presence of the detection signal determines whether the transformer is connected. However, the existing current transformer detection scheme has the following problems: 1. Increased cost. In the existing technical solution, a detection resistor needs to be added to the transformer side. There are two ways to add the detection resistor. One is to add a circuit board on the transformer side. The secondary wiring of the transformer, the detection resistor and the output line are all welded on the circuit board. The circuit board is fixed in the plastic shell by clips or screws. The other is to weld the detection resistor and the transformer secondary output line together and fix them with insulating tape and put them into the plastic shell, and then fill the plastic shell with glue. Both of the above methods require increased material costs and process costs. 2. Large interface space is occupied. In the existing technical solution, the output interface is a three-wire system, which occupies a large space. 3. Reduced reliability. In the existing technical solution, a detection resistor needs to be added to the transformer side. Whether adding a circuit board or welding the resistor directly to the transformer secondary output line, adding devices and welding processes will reduce the reliability of the device. Summary of the Invention

[0003] In order to solve the above problems, the embodiments of the present application provide a current transformer signal sampling and detection device and method.

[0004] In a first aspect, the present application provides a current transformer signal sampling and detection device, comprising a current transformer and a sampling device, wherein the current transformer comprises a primary module and a secondary module, the sampling device comprises a sampling resistor, a detection module, and a sampling module for collecting a signal on the sampling resistor, wherein two ends of the secondary module are respectively connected to corresponding positions on the sampling module, two ends of the sampling resistor are respectively connected to two ends of the secondary module, one end of the sampling resistor is grounded, and the detection module is connected to the other end of the sampling resistor; the detection module provides a first voltage signal to the sampling resistor when the primary module is in a first preset state, the sampling module is configured to collect the first detection signal when the current transformer is not connected, and to collect a second detection signal when the current transformer is connected, the detection module is configured to stop providing the first voltage signal to the sampling resistor when the sampling module collects the second detection signal, the primary module is configured to connect current when the detection module stops providing the first voltage signal to the sampling resistor, and the sampling module is configured to perform metering when the primary module is connected to current.

[0005] Preferably, the sampling module is an ADC chip.

[0006] Preferably, the detection module includes a switch unit, a voltage-dividing resistor and an MCU chip communicating with the sampling module, one end of the voltage-dividing resistor is connected to the other end of the sampling resistor, the two ends of the switch unit are respectively connected to the MCU chip and the voltage-dividing resistor, and when the switch unit is turned on, the MCU chip provides a second voltage signal to the voltage-dividing resistor.

[0007] Preferably, the switching unit includes an analog switch, one end of the analog switch is connected to the IO port 1 of the MCU chip, and the other end of the analog switch is connected to the other end of the voltage divider resistor, and the MCU chip is used to provide a second voltage signal to the voltage divider resistor through the IO port 1 when the analog switch is turned on.

[0008] Preferably, the MCU chip is provided with an IO port 2, and the MCU chip controls the analog switch to be closed or opened through the IO port 2. The MCU chip is used to control the analog switch to be opened through the IO port 2 when the sampling module collects the second detection signal, and the MCU chip controls the IO port 1 to output a low level.

[0009] Preferably, when the sampling module detects that the secondary current signal on the sampling resistor is 0 and lasts for more than a first preset time, the MCU chip controls the analog switch to turn on through IO port 2 and provides a second voltage signal to the voltage divider resistor through IO port 1.

[0010] Preferably, it further includes a first connecting line and a second connecting line, wherein the two ends of the first connecting line are respectively connected to the output positive end of the secondary module and the first part of the sampling module, and the two ends of the second connecting line are respectively connected to the output negative end of the secondary module and the second part of the sampling module, and the two ends of the sampling resistor are respectively connected to the first connecting line and the second connecting line.

[0011] In a second aspect, an embodiment of the present application provides a current transformer signal sampling and detection method, comprising the following steps: S1: Connect the two ends of the secondary module to the corresponding positions on the sampling module, connect the two ends of the sampling resistor to the two ends of the secondary module, ground one end of the sampling resistor, and connect the detection module to the other end of the sampling resistor; S2: The detection module provides a first voltage signal to the sampling resistor when the primary module is in a first preset state; S3: When the sampling module collects the second detection signal, it is determined that the current transformer has been connected; S4: The detection module stops providing the first voltage signal to the sampling resistor; S5: Primary module access current; S6: The sampling module performs measurement work.

[0012] Preferably, the detection module includes a switch unit, a voltage-dividing resistor, and an MCU chip communicating with the sampling module. The switch unit includes an analog switch, one end of the analog switch is connected to IO port 1 of the MCU chip, and the other end of the analog switch is connected to the other end of the voltage-dividing resistor. Step S2 specifically includes: the sampling module collects the secondary current signal on the sampling resistor, and when the sampling module detects that the secondary current signal on the sampling resistor is 0 and the duration exceeds a first preset time, the MCU chip controls the analog switch to turn on through IO port 2 and provides the second voltage signal to the voltage-dividing resistor through IO port 1 and provides the first voltage signal to the sampling resistor.

[0013] Preferably, step S4 specifically includes: when the sampling module collects the second detection signal, the MCU chip controls the analog switch to be disconnected through the IO port 2, and the MCU chip controls the IO port 1 to output a low level.

[0014] The beneficial effects of the present invention are as follows: the detection module provides a first voltage signal to the sampling resistor when the primary module is in a first preset state; the detection module stops providing the first voltage signal to the sampling resistor when the sampling module collects a second detection signal; the primary module connects to the current when the detection module stops providing the first voltage signal to the sampling resistor; the sampling module performs metering when the primary module connects to the current; the present application adds a detection module to the sampling device to realize the current transformer signal sampling and detection functions, without adding a transformer design, and the increased cost of the detection module is much lower than the cost of adding the transformer function; the present application can realize the transformer signal sampling and detection functions through a two-wire interface, and the number of interfaces is increased by 1.5 times compared with the three-wire interface under the same interface space; the present application adds a detection module to the sampling device, and the circuit production process (reflow soldering) is higher than the production process (manual soldering) of adding the transformer function, and the reliability of the equipment is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 A circuit connection diagram of a current transformer signal sampling and detection device provided in an embodiment of the present application; Figure 2 A schematic flow chart of a current transformer signal sampling and detection method provided in an embodiment of the present application; Figure 3 This is a circuit connection diagram of the prior art.

[0017] In the figure: 1-current transformer, 11-primary module, 12-secondary module, 2-sampling device, 21-sampling resistor, 22-ADC chip, 23-detection module. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0019] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present application. Different embodiments can be replaced or combined, so the present application can also be considered to include all possible combinations of the same and / or different embodiments described. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present application should also be considered to include embodiments containing one or more of all other possible combinations of A, B, C, and D, even though the embodiment may not be clearly described in the following text.

[0020] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements described without departing from the scope of the present application. Various examples may appropriately omit, replace, or add various processes or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. In addition, features described in some examples may be combined in other examples.

[0021] See also Figure 1 . Figure 1 A circuit connection diagram of a current transformer signal sampling and detection device provided in an embodiment of the present application. In the embodiment of the present application, the device includes a current transformer 1 and a sampling device 2, wherein the current transformer 1 includes a primary module 11 and a secondary module 12, and the sampling device 2 includes a sampling resistor 21, a detection module 23, and a sampling module for collecting signals on the sampling resistor 21. The two ends of the secondary module 12 are respectively connected to corresponding positions on the sampling module, and the two ends of the sampling resistor 21 are respectively connected to the two ends of the secondary module 12. One end of the sampling resistor 21 is grounded, and the detection module 23 is connected to the other end of the sampling resistor 21; the detection module 23 When the primary module 11 is in a first preset state, a first voltage signal is provided to the sampling resistor 21. The sampling module is configured to collect the first detection signal when the current transformer 1 is not connected, and to collect the second detection signal when the current transformer 1 is connected. The detection module 23 is configured to stop providing the first voltage signal to the sampling resistor 21 when the sampling module collects the second detection signal. The primary module 11 is configured to connect current when the detection module 23 stops providing the first voltage signal to the sampling resistor 21. The sampling module is configured to perform metering when the primary module 11 is connected to current.

[0022] In an embodiment of the present application, the detection module 23 is connected to the other end of the sampling resistor 21, so that when the primary module 11 is in the first preset state, it can provide a first voltage signal to the sampling resistor 21. The sampling module collects the first detection signal when the current transformer 1 is not connected, and collects the second detection signal when the current transformer 1 is connected. If the sampling module collects the second detection signal, it means that the current transformer 1 is connected, and the detection module 23 stops providing the first voltage signal to the sampling resistor 21. The primary module 11 is connected to the current, and the sampling module performs metering. The present application only needs to add the detection module 23 to the sampling device 2 to realize the signal sampling and detection functions of the current transformer 1. The current transformer 1 does not need to add functional design, and can be realized through a two-wire system. The primary module 11 is in the first preset state, that is, the primary module 11 is set to be suspended, the primary module 11 is not connected to the current loop, and the primary module 11 has no input signal.

[0023] In one embodiment, the sampling module is an ADC chip 22 .

[0024] In the embodiment of the present application, the sampling module can also be replaced with other metering chips to achieve the function.

[0025] In one embodiment, the detection module 23 includes a switching unit, a voltage-dividing resistor, and an MCU chip communicating with the sampling module, one end of the voltage-dividing resistor is connected to the other end of the sampling resistor 21, and the two ends of the switch unit are respectively connected to the MCU chip and the voltage-dividing resistor. When the switch unit is turned on, the MCU chip provides a second voltage signal to the voltage-dividing resistor.

[0026] In one embodiment, the switching unit includes an analog switch, one end of the analog switch is connected to the IO port 1 of the MCU chip, and the other end of the analog switch is connected to the other end of the voltage divider resistor. The MCU chip is used to provide a second voltage signal to the voltage divider resistor through the IO port 1 when the analog switch is turned on.

[0027] In the embodiment of the present application, the ADC chip 22 and the MCU can communicate via SPI, II2C, UART, etc. The analog switch can be replaced with other controllable switches, and the detection module 23 can be powered not only by the IO port 1 of the MCU chip, but also by an external power supply.

[0028] In one possible implementation, the MCU chip is provided with an IO port 2, and the MCU chip controls the analog switch to be closed or opened through the IO port 2. The MCU chip is used to control the analog switch to be opened through the IO port 2 when the sampling module collects the second detection signal, and the MCU chip controls the IO port 1 to output a low level.

[0029] In one embodiment, when the sampling module detects that the secondary current signal on the sampling resistor 21 is 0 and lasts for more than a first preset time, the MCU chip controls the analog switch to turn on through IO port 2 and provides a second voltage signal to the voltage divider resistor through IO port 1.

[0030] In this embodiment of the present application, the secondary positive and negative terminals of the current transformer 1 are connected to the device via a two-wire system. A sampling resistor 21 is added between the secondary positive and negative terminals on the device side. When a current signal is present in the primary, the secondary induced current is converted into a voltage signal through the sampling resistor 21 and fed into the ADC chip 22 for sampling and measurement. The analog switch is controlled by the MCU chip. IO port 1 of the MCU provides the voltage signal, and IO port 2 of the MCU controls the on and off of the analog switch. When the ADC chip 22 detects that the secondary current signal is 0 and persists for more than 3 seconds, the MCU chip controls the analog switch through IO port 2.

[0031] In one embodiment, the first connecting line and the second connecting line are further included, wherein two ends of the first connecting line are respectively connected to the positive output end of the secondary module 12 and the first part of the sampling module, and two ends of the second connecting line are respectively connected to the negative output end of the secondary module 12 and the second part of the sampling module, and two ends of the sampling resistor 21 are respectively connected to the first connecting line and the second connecting line.

[0032] In the embodiment of the present application, the secondary module 12 of the current transformer 1 is connected to the sampling device 2 via a first connecting line and a second connecting line, that is, the secondary module 12 is connected to the sampling device 2 via a two-wire system. The two ends of the sampling resistor 21 are respectively connected to a first portion of the first connecting line located within the sampling device 2 and a first portion of the second connecting line located within the sampling device 2.

[0033] In the embodiment of the present application, the detection process is as follows: 1) Sampling device 2 is powered on, the MCU chip provides a voltage signal through IO port 1, and controls the analog switch to close through IO port 2; 2) If the current transformer 1 is connected, the primary of the current transformer 1 is suspended, that is, the primary module 11 is not connected to the current loop, and the primary module 11 has no input signal. The internal resistance of the transformer coil is connected in parallel with the sampling resistor 21 and then divided by the voltage divider resistor to generate a second detection signal. The second detection signal is the voltage signal generated on the sampling resistor 21, recorded as JC1. When the ADC chip 22 collects JC1, it is considered that the transformer has been connected. At this time, the MCU controls the analog switch to disconnect through IO port 2 and controls IO port 1 to output a low level. After detecting that the sensor is connected, there is no need for IO port 1 to output a voltage signal, so it is necessary to output a low level, and then the primary module 11 of the current transformer 1 is connected to the current for metering. The current sensor is used to collect current signals and measure the size of the current signal. Generally, the system will also collect voltage signals. Once both voltage and current signals are collected, power calculation and energy accumulation can be performed. 3) If the current transformer 1 is not connected, the first detection signal generated by the voltage division of the sampling resistor 21 and the voltage divider resistor is recorded as JC2. When the ADC chip 22 collects JC2, it is considered that the current transformer is not connected. At this time, the MCU continues to detect until the current transformer is connected.

[0034] 4) During the operation of the sampling device 2, when the ADC chip 22 detects that the secondary current signal is 0 and lasts for more than 3 seconds, the MCU chip provides a voltage signal through the IO port 1 and controls the analog switch to close through the IO port 2.

[0035] 5) If JC2 is detected, it is considered that the transformer has been unplugged.

[0036] 6) If JC1 is detected, it is considered that the transformer is still connected, and the MCU chip controls the analog switch through IO port 2 to disconnect, controls IO port 1 to output a low level, and then continues to perform measurement work.

[0037] In the embodiment of the present application, the present invention implements the two-wire mutual inductor signal sampling and detection functions by providing a detection module 23 in the sampling device 2 and coordinating with a software algorithm. The key innovations are as follows: 1. A detection module 23 is added to the sampling device 2. The detection module 23 includes but is not limited to a voltage divider resistor, an analog switch, and an MCU chip.

[0038] 2. The detection module 23 cooperates with the software algorithm to realize the detection function of the current transformer 1, and can realize the insertion or removal of the current transformer 1 without affecting the normal sampling function of the transformer.

[0039] The following will be combined with the Figure 2 , a current transformer signal sampling and detection method provided in an embodiment of the present application is introduced in detail. Figure 2A current transformer signal sampling and detection method shown is applied in this application Figure 1 The device of the embodiment shown.

[0040] like Figure 2 As shown, the method is applied to the above-mentioned current transformer signal sampling and detection device, comprising the following steps: S1: Connect the two ends of the secondary module 12 to the corresponding positions on the sampling module, connect the two ends of the sampling resistor 21 to the two ends of the secondary module 12, ground one end of the sampling resistor 21, and connect the detection module 23 to the other end of the sampling resistor 21; S2: The detection module 23 provides a first voltage signal to the sampling resistor 21 when the primary module 11 is in a first preset state; S3: When the sampling module collects the second detection signal, it is determined that the current transformer 1 has been connected; S4: The detection module 23 stops providing the first voltage signal to the sampling resistor 21; S5: The primary module 11 is connected to the current; S6: The sampling module performs measurement work.

[0041] In an embodiment of the present application, the detection module 23 provides a first voltage signal to the sampling resistor 21 when the primary module 11 is in a first preset state. The sampling module is used to collect the first detection signal when the current transformer 1 is not connected and to collect the second detection signal when the current transformer 1 is connected. The detection module 23 is used to stop providing the first voltage signal to the sampling resistor 21 when the sampling module collects the second detection signal. The primary module 11 is used to connect the current when the detection module 23 stops providing the first voltage signal to the sampling resistor 21. The sampling module is used to perform metering when the primary module 11 is connected to the current.

[0042] In one embodiment, the detection module 23 includes a switch unit, a voltage-dividing resistor, and an MCU chip communicating with the sampling module. The switch unit includes an analog switch, one end of the analog switch is connected to the IO port 1 of the MCU chip, and the other end of the analog switch is connected to the other end of the voltage-dividing resistor. Step S2 specifically includes: the sampling module collects the secondary current signal on the sampling resistor 21, and when the sampling module detects that the secondary current signal on the sampling resistor 21 is 0 and the duration exceeds a first preset time, the MCU chip controls the analog switch to turn on through the IO port 2 and provides the second voltage signal to the voltage-dividing resistor through the IO port 1 and provides the first voltage signal to the sampling resistor 21.

[0043] In the embodiment of the present application, when the ADC chip 22 detects that the secondary current signal is 0 and lasts for more than 3 seconds, the MCU chip provides a voltage signal through IO port 1 and controls the analog switch to be closed through IO port 2.

[0044] In one possible implementation, step S4 specifically includes: when the sampling module collects the second detection signal, the MCU chip controls the analog switch to be disconnected through the IO port 2, and the MCU chip controls the IO port 1 to output a low level.

[0045] In an embodiment of the present application, if the current transformer 1 is connected, the internal resistance of the coil of the current transformer 1 is connected in parallel with the sampling resistor 21 and then divided by the voltage dividing resistor to generate a second detection signal, recorded as JC1. When the ADC chip 22 collects JC1, it is considered that the current transformer 1 has been connected. At this time, the MCU chip controls the analog switch to be disconnected through the IO port 2, and controls the IO port 1 to output a low level.

[0046] Those skilled in the art will clearly understand that the technical solutions of the embodiments of the present application can be implemented with the help of software and / or hardware. "Unit," "module," and "section" in this specification refer to software and / or hardware that can independently perform or cooperate with other components to perform specific functions, where the hardware can be, for example, a Field-Programmable Gate Array (FPGA) or an Integrated Circuit (IC).

[0047] It should be noted that for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0048] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0049] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some service interface, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

[0050] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0051] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0052] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a memory and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned memory includes: U disk, read-only memory (ROM), random access memory (RAM), mobile hard disk, magnetic disk, or optical disk, etc., various media that can store program code.

[0053] Those skilled in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be completed by instructing related hardware through a program. The program may be stored in a computer-readable memory, which may include a flash drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0054] The above is only an exemplary embodiment of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure. After considering the specification and practicing the disclosure herein, those skilled in the art will easily think of the implementation scheme of the present disclosure. This application is intended to cover any variation, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not recorded in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A current transformer signal sampling and detection device, characterized in that: The invention comprises a current transformer (1) and a sampling device (2), wherein the current transformer (1) comprises a primary module (11) and a secondary module (12), and the sampling device (2) comprises a sampling resistor (21), a detection module (23), and a sampling module for collecting a signal on the sampling resistor (21), wherein two ends of the secondary module (12) are respectively connected to corresponding positions on the sampling module, and two ends of the sampling resistor (21) are respectively connected to two ends of the secondary module (12), one end of the sampling resistor (21) is grounded, and the detection module (23) is connected to the other end of the sampling resistor (21); the detection module (23) When the primary module (11) is in a first preset state, a first voltage signal is provided to the sampling resistor (21); the sampling module is used to collect the first detection signal when the current transformer (1) is not connected, and to collect the second detection signal when the current transformer (1) is connected; the detection module (23) is used to stop providing the first voltage signal to the sampling resistor (21) when the sampling module collects the second detection signal; the primary module (11) is used to connect the current when the detection module (23) stops providing the first voltage signal to the sampling resistor (21); and the sampling module is also used to perform metering when the primary module (11) is connected to the current.

2. A current transformer signal sampling and detection device according to claim 1, characterized in that: The sampling module is an ADC chip (22).

3. A current transformer signal sampling and detection device according to claim 1 or 2, characterized in that: The detection module (23) comprises a switch unit, a voltage-dividing resistor, and an MCU chip communicating with the sampling module, one end of the voltage-dividing resistor is connected to the other end of the sampling resistor (21), and both ends of the switch unit are respectively connected to the MCU chip and the voltage-dividing resistor, and when the switch unit is turned on, the MCU chip provides a second voltage signal to the voltage-dividing resistor.

4. A current transformer signal sampling and detection device according to claim 3, characterized in that: The switching unit includes an analog switch, one end of the analog switch is connected to the IO port 1 of the MCU chip, and the other end of the analog switch is connected to the other end of the voltage divider resistor. The MCU chip is used to provide a second voltage signal to the voltage divider resistor through the IO port 1 when the analog switch is turned on.

5. The current transformer signal sampling and detection device according to claim 4, characterized in that: The MCU chip is provided with an IO port 2, and the MCU chip controls the analog switch to be closed or opened through the IO port 2. The MCU chip is used to control the analog switch to be opened through the IO port 2 when the sampling module collects the second detection signal. The MCU chip controls the IO port 1 to output a low level.

6. A current transformer signal sampling and detection device according to claim 5, characterized in that: When the sampling module detects that the secondary current signal on the sampling resistor (21) is 0 and the duration exceeds a first preset time, the MCU chip controls the analog switch to be turned on through the IO port 2 and provides the second voltage signal to the voltage divider resistor through the IO port 1.

7. A current transformer signal sampling and detection device according to claim 1 or 2, characterized in that: It also includes a first connecting line and a second connecting line, wherein the two ends of the first connecting line are respectively connected to the output positive end of the secondary module (12) and the first part of the sampling module, and the two ends of the second connecting line are respectively connected to the output negative end of the secondary module (12) and the second part of the sampling module, and the two ends of the sampling resistor (21) are respectively connected to the first connecting line and the second connecting line.

8. A signal sampling and detection method applied to a current transformer signal sampling and detection device according to any one of claims 1 to 7, characterized in that: The steps include: S1: Connect the two ends of the secondary module (12) to the corresponding positions on the sampling module, connect the two ends of the sampling resistor (21) to the two ends of the secondary module (12), ground one end of the sampling resistor (21), and connect the detection module (23) to the other end of the sampling resistor (21); S2: the detection module (23) provides a first voltage signal to the sampling resistor (21) when the primary module (11) is in a first preset state; S3: when the sampling module collects the second detection signal, it is determined that the current transformer (1) has been connected; S4: the detection module (23) stops providing the first voltage signal to the sampling resistor (21); S5: primary module (11) receives current; S6: The sampling module performs measurement work.

9. A current transformer signal sampling and detection method according to claim 8, characterized in that: The detection module (23) includes a switch unit, a voltage divider resistor, and an MCU chip communicating with the sampling module. The switch unit includes an analog switch, one end of the analog switch is connected to the IO port 1 of the MCU chip, and the other end of the analog switch is connected to the other end of the voltage divider resistor. Step S2 specifically includes: the sampling module collects the secondary current signal on the sampling resistor (21), and the MCU chip controls the analog switch to be turned on through the IO port 2 when the sampling module detects that the secondary current signal on the sampling resistor (21) is 0 and the duration exceeds a first preset time, and provides the second voltage signal to the voltage divider resistor through the IO port 1 and provides the first voltage signal to the sampling resistor (21).

10. A current transformer signal sampling and detection method according to claim 9, characterized in that: Step S4 specifically includes: when the sampling module collects the second detection signal, the MCU chip controls the analog switch to be disconnected through the IO port 2, and the MCU chip controls the IO port 1 to output a low level.

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