Current monitor based on power taking, energy supply and signal acquisition of double current transformers

Abstract

The invention discloses a current monitor based on power taking, energy supply and signal acquisition of double current transformers, which comprises an energy management module, a power management module, a microcontroller, a wireless transmitting module, a signal processing module, a first current transformer and a second current transformer, and is characterized in that the first current transformer and the second current transformer are used for acquiring current of electric equipment; the energy management module collects and stores electric energy from the first current transformer; the power management module obtains electric energy to supply power to active components in the microcontroller and the current monitor; the signal processing module receives a current signal sent by the second current transformer, amplifies the current signal and sends the amplified current signal to the microcontroller; the microcontroller receives the signal sent by the signal processing module and calculates an actual current value; and the wireless transmitting module wirelessly transmits the calculated current value to the receiver. According to the invention, signal collection is carried out by one current transformer, energy collection is carried out by the other current transformer, and current monitoring when the electric equipment is in a low-power working state can be realized.

Description

Technical Field

[0001] The invention relates to a current monitoring technology, in particular to a current monitor based on power supply and signal acquisition of double current transformers. Background Art

[0002] Some electrical equipment in the fields of power systems, industrial automation, energy management, etc. will be equipped with current monitors to monitor their currents, so that the staff can monitor the working status of the electrical equipment. Existing current monitors are generally equipped with a single current transformer (CT) to realize signal acquisition. The current transformer uses the principle of electromagnetic induction to obtain the current in the industrial frequency AC circuit of the electrical equipment in the working state to realize current data acquisition. In order to save energy, people consider using the current transformer to collect energy to power the current monitor when it is not collecting signals. However, a single current transformer is used for signal acquisition and energy collection at the same time. During data collection, the current passes through the sampling resistor, and the sampling resistor has a resistance value between tens of milliohms and several ohms. The output voltage of the current transformer is pulled down to between tens of millivolts and hundreds of millivolts. When it is used for energy collection, the electrical energy obtained is less, which cannot meet the energy supply of the current monitor. Therefore, the existing current monitors generally need to be equipped with additional power supply to work properly. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that the existing current monitor needs to be equipped with an additional power supply to work normally, and provides a current monitor based on dual current transformer power supply and signal acquisition, which uses two current transformers to work synchronously for signal acquisition and energy collection respectively, and can continuously power the current monitor in a passive state.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] A current monitor based on dual current transformer power supply and signal acquisition includes an energy management module, a power management module, a microcontroller, a wireless transmission module, a signal processing module and two current transformers, the two current transformers are respectively a first current transformer and a second current transformer, wherein:

[0006] A first current transformer, connected to the energy management module, is used to collect the current in the industrial frequency AC circuit of the electrical equipment in the working state and convert it into AC power of a set ratio and send it to the energy management module;

[0007] The second current transformer is connected to the signal processing module and is used to collect the current in the power frequency AC circuit of the electrical equipment in the working state and convert it into a small current signal of a set ratio and send it to the signal processing module;

[0008] An energy management module, connected to the power management module, for collecting and storing electric energy from the first current transformer for scheduling by the power management module;

[0009] The power management module is connected to the microcontroller and other active components in the current monitor, and obtains electric energy from the energy management module to power the microcontroller and the active components in the current monitor; and is used to receive the control signal generated by the microcontroller to control the on and off of the power supply circuit of the active components in the current monitor;

[0010] A signal processing module, used for receiving the current signal sent by the second current transformer and amplifying it to a set microcontroller processing level and then sending it to the microcontroller;

[0011] The microcontroller is used to generate a control signal for controlling the on / off of the power supply line of the active components in the current monitor and send it to the power management module; it is used to receive the signal sent by the signal processing module and calculate the actual current value, and then send the current value to the wireless transmission module;

[0012] The wireless transmission module is used to receive the current value sent by the microcontroller and wirelessly transmit the calculated current value to a receiver that remotely interacts with the current monitor.

[0013] The present invention provides a passive wireless current monitor solution that uses two current transformers (CTs) to collect signals and collect energy respectively. The system uses one current transformer to collect signals, and the other current transformer does not perform sampling but is only used for energy collection. The two current transformers work together to ensure that the current monitor can monitor the current of the electrical equipment and transmit wireless data.

[0014] Furthermore, the energy management module includes an AC / DC rectifier and voltage regulator module and an energy storage module, wherein:

[0015] An AC / DC rectifier and voltage regulator module is connected to the first current transformer and is used to convert the alternating current output by the first current transformer into direct current and send it to the energy storage module;

[0016] The energy storage module is used to receive and store the electric energy output by the AC / DC rectifier and voltage regulator module.

[0017] Furthermore, the AC / DC rectifier and voltage regulator module includes a bridge rectifier circuit composed of four Schottky diodes and a voltage regulator diode, the two input ends of the bridge rectifier circuit are respectively connected one-to-one with the two output ends of the first current transformer, one output end of the bridge rectifier circuit is connected to the energy storage module, and the other output end is grounded; the positive electrode of the voltage regulator diode is grounded, and the negative electrode thereof is connected to the line between the bridge rectifier circuit and the energy storage module.

[0018] Furthermore, the energy management module also includes an overvoltage protection module connected to the energy storage module, and the overvoltage protection module is used to monitor the voltage of the energy storage module and discharge the electric energy stored in the energy storage module when the voltage of the energy storage module exceeds a set discharge threshold.

[0019] Furthermore, the overvoltage protection module includes a voltage comparator, a power resistor and a first NMOS tube, the input end of the voltage comparator is connected to the energy storage module, and its output end is connected to the gate of the first NMOS tube, the two ends of the power resistor are respectively connected to the input end of the voltage comparator and the drain of the first NMOS tube, and the source of the first NMOS tube is grounded.

[0020] Furthermore, the power management module includes a hysteresis comparator, a DC / DC conversion module and a power switch, the hysteresis comparator is connected to the DC / DC conversion module, the hysteresis comparator and the DC / DC conversion module are both connected to the energy storage module, and the DC / DC conversion module is connected to the microcontroller and the power switch, wherein:

[0021] A hysteresis comparator is used to monitor the upper and lower limits of the energy storage voltage threshold of the energy storage module. When the energy storage module voltage reaches the set upper threshold, the DC / DC conversion module is enabled, and when the energy storage voltage reaches the set lower threshold, the DC / DC conversion module is turned off;

[0022] A DC / DC conversion module, used to control the voltage increase or decrease of the DC power output by the energy storage module;

[0023] The power switch is connected to the active components in the current monitor and is used to receive the control signal generated by the microcontroller to control the on and off of the power supply circuit of the active components in the current monitor.

[0024] Furthermore, the signal processing module is implemented using an operational amplifier or an electric energy metering chip. The operational amplifier is used to receive the current signal sent by the second current transformer and amplify it to a set microcontroller processing level and send it to the microcontroller. The electric energy metering chip receives the current signal sent by the second current transformer and sends it to the microcontroller after signal amplification, ADC conversion, filtering and data processing calculation.

[0025] Further, the signal processing module is implemented by an electric energy metering chip, and the signal processing module includes a sampling resistor R403, a resistor R402, a resistor R405, a capacitor C403, a capacitor C404, a capacitor C405 and an electric energy metering chip U403, and the electric energy metering chip U403 is implemented by a HLW8112 metering chip, and the two ends of the sampling resistor R403 are respectively connected to the two output ends of the second current mutual inductance in a one-to-one correspondence, one end of the resistor R402 is connected to one end of the sampling resistor R403, and the other end thereof is connected to the IAP pin of the electric energy metering chip U403. The capacitor C403 is connected to the circuit between the resistor R402 and the electric energy metering chip U403, and the other end thereof is grounded; the resistor R405 is connected to one end of the sampling resistor R403, and the other end thereof is connected to the IAN pin of the electric energy metering chip U403; the capacitor C404 is connected to the circuit between the resistor R405 and the electric energy metering chip U403, and the other end thereof is grounded; the resistor R403 is connected to one end of the resistor R405 and is grounded; the capacitor C405 is connected to the VREF pin of the electric energy metering chip U403, and the other end thereof is grounded.

[0026] Furthermore, the current monitor based on dual current transformer power supply and signal acquisition also includes a temperature and humidity sensor connected to the microcontroller, and the temperature and humidity sensor is used to collect current environmental temperature and humidity data at set time intervals and send it to the microcontroller. The microcontroller compares the acquired temperature and humidity data with the set temperature and humidity thresholds, and generates a warning message when the set thresholds are exceeded.

[0027] In summary, compared with the prior art, the present invention has the following beneficial effects: the present invention provides a passive wireless current monitor, which uses two current transformers (CT) as a signal collector and a passive energy collector respectively. The electric energy collected by the current transformer as a passive energy collector is used to power the microcontroller and other active components in the current monitor. The current transformer that collects energy does not collect data through a sampling resistor, which can ensure that the electric energy is normally acquired. In this way, the present invention can ensure that the current monitor does not need to be equipped with an additional power supply, save energy, and make the current monitor easier to promote and apply. This has broad application prospects in the fields of power systems, industrial automation, and energy management. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0029] Figure 1 A system block diagram of a specific embodiment of the present invention;

[0030] Figure 2A circuit schematic diagram of an energy management module in a specific embodiment of the present invention;

[0031] Figure 3 The figure is a circuit schematic diagram of a signal processing module and its peripheral components in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0033] Embodiment 1:

[0034] like Figure 1 As shown, a current monitor based on dual current transformer power supply and signal acquisition includes an energy management module, a power management module, a microcontroller, a wireless transmission module, a signal processing module and two current transformers, the two current transformers are respectively a first current transformer and a second current transformer, wherein: the first current transformer is connected to the energy management module, and is used to collect the current in the industrial frequency AC circuit of the electrical equipment in the working state and convert it into a set proportion of AC power and send it to the energy management module; the second current transformer is connected to the signal processing module, and is used to collect the current in the industrial frequency AC circuit of the electrical equipment in the working state and convert it into a small current signal of a set proportion and send it to the signal processing module; the energy management module is connected to the power management module, and is used to collect and store electric energy from the first current transformer for scheduling by the power management module; The management module is connected to the microcontroller and other active components in the current monitor, and obtains electric energy from the energy management module to power the microcontroller and the active components in the current monitor; it is used to receive the control signal generated by the microcontroller to control the on-off of the power supply line of the active components in the current monitor; the signal processing module is used to receive the current signal sent by the second current transformer and amplify it to the set microcontroller processing level and then send it to the microcontroller; the microcontroller is used to generate a control signal for controlling the on-off of the power supply line of the active components in the current monitor and send it to the power management module; it is used to receive the signal sent by the signal processing module and calculate the actual current value, and then send the current value to the wireless transmission module; the wireless transmission module is used to receive the current value sent by the microcontroller and wirelessly transmit the calculated current value to a receiver that remotely interacts with the current monitor.

[0035] In the specific implementation of this embodiment, two current transformers collect the current in the power frequency AC circuit of the electrical equipment in the working state according to the principle of electromagnetic induction, the second current transformer is used for signal acquisition, and the first current transformer is used as an energy acquisition source to enhance the power supply capacity of the system. The wireless transmission module of this embodiment adopts low-power wireless communication technology, such as Zigbee, low-power Bluetooth (BLE), 433MHz or LoRa. The microcontroller of this embodiment is preferably implemented by an 8 / 32-bit single-chip microcomputer.

[0036] The energy management module of this embodiment is responsible for collecting electric energy from the first current transformer, stabilizing the output voltage, and storing electric energy for use by the system. The energy management module includes an AC / DC rectifier and voltage regulator module and an energy storage module, wherein: the AC / DC rectifier and voltage regulator module is connected to the first current transformer, and is used to convert the alternating current output by the first current transformer into direct current and send it to the energy storage module; the energy storage module is used to receive and store the electric energy output by the AC / DC rectifier and voltage regulator module.

[0037] like Figure 2 As shown, the AC / DC rectifier and voltage regulator module of this embodiment includes a bridge rectifier circuit composed of four Schottky diodes and a voltage regulator diode. The four Schottky diodes of the bridge rectifier circuit are Figure 2 In the figure, they are Schottky diode D401, Schottky diode D402, Schottky diode D404 and Schottky diode D405 respectively, the voltage regulator diode is voltage regulator diode D403, the two input ends of the bridge rectifier circuit are respectively connected to the two output ends of the current transformer in a one-to-one correspondence, one output end of the bridge rectifier circuit is connected to the energy storage module, and the other output end is grounded; the positive electrode D403 of the voltage regulator diode in this embodiment is grounded, and the negative electrode thereof is connected to the line between the bridge rectifier circuit and the energy storage module, and the positive electrode D403 of the voltage regulator diode is used to prevent the voltage after rectification from being too high. Figure 2 The J401 interface is connected to the first current transformer.

[0038] The energy management module of this embodiment also includes an overvoltage protection module connected to the energy storage module, and the overvoltage protection module is used to monitor the voltage of the energy storage module, and discharge the electric energy stored in the energy storage module when the voltage of the energy storage module exceeds the set discharge threshold. The overvoltage protection module of this embodiment includes a voltage comparator U401, a power resistor R401 and a first NMOS tube Q401, wherein the input end of the voltage comparator U401 is connected to the energy storage module, and its output end is connected to the gate of the first NMOS tube Q401, and the two ends of the power resistor R401 are respectively connected to the input end of the voltage comparator U401 and the drain of the first NMOS tube Q401, and the source of the first NMOS tube Q401 is grounded. The energy storage module of this embodiment uses an energy storage capacitor or a battery to store the electric energy collected from the first current transformer. Figure 2The energy storage module uses a farad capacitor. In this embodiment, an overvoltage protection module (OVP) performs overvoltage protection through voltage detection. When the voltage exceeds the threshold, it is discharged through resistance consumption to avoid the energy storage module exceeding the storage voltage upper limit and causing damage to the back-end chip.

[0039] The power management module of this embodiment includes a hysteresis comparator, a DC / DC conversion module and a power switch, wherein the hysteresis comparator is connected to the DC / DC conversion module, the hysteresis comparator and the DC / DC conversion module are both connected to the energy storage module, and the DC / DC conversion module is connected to the microcontroller and the power switch, wherein: the hysteresis comparator is used to monitor the upper and lower limits of the energy storage voltage threshold of the energy storage module, and when the energy storage module voltage reaches the set upper threshold, the DC / DC conversion module is enabled, and when the energy storage voltage reaches the set lower threshold, the DC / DC conversion module is turned off; the DC / DC conversion module is used to boost or buck the DC power output by the energy storage module to ensure stable output; the power switch is connected to the active components in the current monitor, and is used to receive the control signal generated by the microcontroller to control the on and off of the power supply line of the active components in the current monitor. The hysteresis comparator of this embodiment is preferably implemented by the MIC841HYC5 chip, the DC / DC conversion module is preferably implemented by the Buck / Boost power chip, and the power switch is preferably implemented by the MOSFET.

[0040] The signal processing module of this embodiment is implemented by an operational amplifier or an electric energy metering chip, wherein the operational amplifier is used to receive the current signal sent by the first current transformer and amplify it to the set microcontroller processing level and send it to the microcontroller, and the electric energy metering chip receives the current signal sent by the first current transformer and sends it to the microcontroller after signal amplification, ADC conversion, filtering and data processing calculation. When the operational amplifier is used in this embodiment, the operational amplifier is preferably implemented by the current sensing amplifier INA199, and when the electric energy metering chip is used in this embodiment, the electric energy metering chip is preferably implemented by the HLW8112 metering chip. When the signal processing module is implemented by the electric energy metering chip, such as Figure 3As shown, the signal processing module of this embodiment includes a sampling resistor R403, a resistor R402, a resistor R405, a capacitor C403, a capacitor C404, a capacitor C405 and an electric energy metering chip U403, wherein the two ends of the sampling resistor R403 are respectively connected to the two output ends of the second current mutual inductance in a one-to-one correspondence, one end of the resistor R402 is connected to one end of the sampling resistor R403, and the other end thereof is connected to the IAP pin of the electric energy metering chip U403; one end of the capacitor C403 is connected to the resistor R402 and the electric energy metering chip U403; The circuit between the energy metering chip U403 and the power metering chip U403 is connected to one end of the resistor R405, and the other end thereof is grounded; one end of the resistor R405 is connected to one end of the sampling resistor R403, and the other end thereof is connected to the IAN pin of the energy metering chip U403; one end of the capacitor C404 is connected to the circuit between the resistor R405 and the energy metering chip U403, and the other end thereof is grounded; one end of the resistor R403 connected to the resistor R405 is grounded; one end of the capacitor C405 is connected to the VREF pin of the energy metering chip U403, and the other end thereof is grounded. Figure 3 The J402 interface is connected to the second current transformer. The secondary induction output of the second current transformer forms a voltage signal of mV level through the sampling resistor R403. The resistor R402, the resistor R405, the capacitor C403 and the capacitor C404 form a low-pass filter. The corresponding current data is obtained by internal amplification of the energy metering chip U403, ADC sampling, filtering and calculation. The microcontroller reads the corresponding register through the SPI bus to complete the current data sampling. The power switch of this embodiment is Figure 3 The middle power control switch U402, when its third pin is at a high level, turns on the power supply to the power metering chip U403, and turns off the power supply when it is at a low level.

[0041] When this embodiment is applied, the two current transformers sense the current in the power frequency AC circuit of the electrical equipment in the working state, generate voltage and current proportional to the current, and the first current transformer outputs the AC signal and is rectified and stabilized. The energy management module collects the electrical energy from the first current transformer, and finally stores the converted energy to ensure a stable power supply for the system. The microcontroller is responsible for coordinating the power consumption of the entire system and extending the life of the energy storage module by disconnecting the power supply lines of unnecessary components.

[0042] Embodiment 2:

[0043] Overheating of the cable and high ambient temperature may cause current overload, posing the risk of fire. Excessive humidity may lead to water leakage in the surrounding area, causing corrosion, insulation failure, etc. In order to monitor the power environment of the monitored electrical equipment, this embodiment makes the following further limitations on the basis of Embodiment 1: This embodiment also includes a temperature and humidity sensor connected to the microcontroller, wherein the temperature and humidity sensor is used to collect current ambient temperature and humidity data at set time intervals and send it to the microcontroller. The microcontroller compares the acquired temperature and humidity data with the set temperature and humidity thresholds, and generates a warning message when the set thresholds are exceeded. When this embodiment is applied, the data collected by the temperature and humidity sensor is processed by the microcontroller and sent to the wireless transmission module, which transmits the data wirelessly to a remote receiver. Figure 3 As shown, the temperature and humidity sensor of this embodiment also controls whether to supply power through the power control switch U402. When the third pin of the power control switch U402 is at a high level, the power supply is turned on, and when the pin is at a low level, the power supply is turned off.

[0044] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of 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 current monitor based on dual current transformers for power supply and signal acquisition, characterized in that: It includes an energy management module, a power management module, a microcontroller, a wireless transmission module, a signal processing module and two current transformers, the two current transformers are respectively a first current transformer and a second current transformer, wherein: A first current transformer, connected to the energy management module, is used to collect the current in the industrial frequency AC circuit of the electrical equipment in the working state and convert it into AC power of a set ratio and send it to the energy management module; The second current transformer is connected to the signal processing module and is used to collect the current in the power frequency AC circuit of the electrical equipment in the working state and convert it into a small current signal of a set ratio and send it to the signal processing module; An energy management module, connected to the power management module, for collecting and storing electric energy from the first current transformer for scheduling by the power management module; The power management module is connected to the microcontroller and other active components in the current monitor, and obtains electric energy from the energy management module to power the microcontroller and the active components in the current monitor; and is used to receive the control signal generated by the microcontroller to control the on and off of the power supply circuit of the active components in the current monitor; A signal processing module, used for receiving the current signal sent by the second current transformer and amplifying it to a set microcontroller processing level and then sending it to the microcontroller; The microcontroller is used to generate a control signal for controlling the on / off of the power supply line of the active components in the current monitor and send it to the power management module; it is used to receive the signal sent by the signal processing module and calculate the actual current value, and then send the current value to the wireless transmission module; The wireless transmission module is used to receive the current value sent by the microcontroller and wirelessly transmit the calculated current value to a receiver that remotely interacts with the current monitor.

2. The current monitor based on dual current transformer power supply and signal acquisition according to claim 1 is characterized in that: The energy management module includes an AC / DC rectifier and voltage regulator module and an energy storage module, wherein: An AC / DC rectifier and voltage regulator module is connected to the first current transformer and is used to convert the alternating current output by the first current transformer into direct current and send it to the energy storage module; The energy storage module is used to receive and store the electric energy output by the AC / DC rectifier and voltage regulator module.

3. The current monitor based on dual current transformer power supply and signal acquisition according to claim 2 is characterized in that: The AC / DC rectifier and voltage regulator module includes a bridge rectifier circuit composed of four Schottky diodes and a voltage regulator diode. The two input ends of the bridge rectifier circuit are respectively connected to the two output ends of the first current transformer in a one-to-one correspondence. One output end of the bridge rectifier circuit is connected to the energy storage module, and the other output end is grounded. The positive electrode of the voltage regulator diode is grounded, and the negative electrode thereof is connected to the line between the bridge rectifier circuit and the energy storage module.

4. The current monitor based on dual current transformer power supply and signal acquisition according to claim 2 is characterized in that: The energy management module also includes an overvoltage protection module connected to the energy storage module, and the overvoltage protection module is used to monitor the voltage of the energy storage module and discharge the electric energy stored in the energy storage module when the voltage of the energy storage module exceeds a set discharge threshold.

5. The current monitor based on dual current transformer power supply and signal acquisition according to claim 4 is characterized in that: The overvoltage protection module includes a voltage comparator, a power resistor and a first NMOS tube. The input end of the voltage comparator is connected to the energy storage module, and its output end is connected to the gate of the first NMOS tube. The two ends of the power resistor are respectively connected to the input end of the voltage comparator and the drain of the first NMOS tube, and the source of the first NMOS tube is grounded.

6. The current monitor based on dual current transformer power supply and signal acquisition according to claim 1 is characterized in that: The power management module includes a hysteresis comparator, a DC / DC conversion module and a power switch, wherein the hysteresis comparator is connected to the DC / DC conversion module, the hysteresis comparator and the DC / DC conversion module are both connected to the energy storage module, and the DC / DC conversion module is connected to the microcontroller and the power switch, wherein: A hysteresis comparator is used to monitor the upper and lower limits of the energy storage voltage threshold of the energy storage module. When the energy storage module voltage reaches the set upper threshold, the DC / DC conversion module is enabled, and when the energy storage voltage reaches the set lower threshold, the DC / DC conversion module is turned off; A DC / DC conversion module, used to control the voltage increase or decrease of the DC power output by the energy storage module; The power switch is connected to the active components in the current monitor and is used to receive the control signal generated by the microcontroller to control the on and off of the power supply circuit of the active components in the current monitor.

7. The current monitor based on dual current transformer power supply and signal acquisition according to claim 1 is characterized in that: The signal processing module is implemented by an operational amplifier or an electric energy metering chip. The operational amplifier is used to receive the current signal sent by the second current transformer and amplify it to a set microcontroller processing level and send it to the microcontroller. The electric energy metering chip receives the current signal sent by the second current transformer and sends it to the microcontroller after signal amplification, ADC conversion, filtering and data processing calculation.

8. The current monitor based on dual current transformer power supply and signal acquisition according to claim 7 is characterized in that: The signal processing module is implemented by an electric energy metering chip, and the signal processing module includes a sampling resistor R403, a resistor R402, a resistor R405, a capacitor C403, a capacitor C404, a capacitor C405 and an electric energy metering chip U403. The electric energy metering chip U403 is implemented by a HLW8112 metering chip. The two ends of the sampling resistor R403 are respectively connected to the two output ends of the second current mutual inductance in a one-to-one correspondence. One end of the resistor R402 is connected to one end of the sampling resistor R403, and the other end thereof is connected to the IAP pin of the electric energy metering chip U403. One end of the capacitor C403 is connected to the line between the resistor R402 and the electric energy metering chip U403, and the other end thereof is grounded; one end of the resistor R405 is connected to one end of the sampling resistor R403, and the other end thereof is connected to the IAN pin of the electric energy metering chip U403; one end of the capacitor C404 is connected to the line between the resistor R405 and the electric energy metering chip U403, and the other end thereof is grounded; one end of the resistor R403 connected to the resistor R405 is grounded; one end of the capacitor C405 is connected to the VREF pin of the electric energy metering chip U403, and the other end thereof is grounded.

9. The current monitor based on dual current transformer power supply and signal acquisition according to any one of claims 1 to 8, characterized in that: It also includes a temperature and humidity sensor connected to the microcontroller, which is used to collect current environmental temperature and humidity data at set time intervals and send them to the microcontroller. The microcontroller compares the acquired temperature and humidity data with set temperature and humidity thresholds, and generates an early warning message when the set thresholds are exceeded.

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