Null line and live line reverse connection detection method and device, medium and electric energy meter
By adding error judgment steps to the zero-fire reverse connection detection circuit, the problem of inaccurate detection of fire neutral connection cannot be accurately detected under an isolated power supply environment, and more accurate detection results and normal calibration process are achieved.
Patent Information
- Application Number
- CN202510378426.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2025-06-20
AI Technical Summary
The existing zero-fire reverse connection detection circuit cannot accurately identify whether the live and neutral wire are reversed in the isolated power environment of the calibrator, which may lead to misjudgment and interruption of the calibration process.
By obtaining the measured voltage value, converting it into the effective voltage value, the relative error with the preset standard voltage is calculated. If the error is greater than the preset value, zero-fire reverse detection is performed.
It effectively avoids misjudgment without testing, and accurately determines whether the fire neutral wire is reversed when testing is required, ensuring the normal progress of the calibration process.
Smart Images
Figure CN120177853A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of circuit detection, and particularly to a method, device, medium and electric energy meter for detecting reverse connection of live wire and neutral wire. Background Art
[0002] Existing reverse connection detection circuits for live wire and neutral wire usually use induction antennas to capture the electric field signals of the live wire and the neutral wire. The core components of the detection circuit include field effect transistors and triodes. When the induction antenna detects the signals of the live wire and the neutral wire, this signal is first transmitted to the field effect transistor, causing a change in its drain level. This change further affects the base level of the triode, thereby controlling the on and off states of the triode. Finally, the MCU determines whether the live wire and the neutral wire are reversely connected by reading the level of the collector of the triode.
[0003] However, when the electric energy meter is calibrated on the calibration bench, since the power supply of the calibration bench is an isolated power supply, the detection circuit may not be able to accurately identify whether the live wire and the neutral wire are reversely connected. In this case, directly performing the reverse connection detection of the live wire and the neutral wire may result in misjudgment, and even wrongly trigger the relay disconnection operation, causing the calibration process to be interrupted and the calibration work cannot be completed normally. Summary of the Invention
[0004] To solve the above problems, the present invention provides a method for detecting reverse connection of live wire and neutral wire, including the following processes: Obtain the measured voltage value; Convert the measured voltage value into the effective voltage value; Calculate the relative error between the effective voltage value and the preset standard voltage; If the relative error is greater than the preset error value, perform the reverse connection detection of the live wire and the neutral wire.
[0005] The relative error being greater than the preset error value indicates that the currently connected power supply is the mains power, and the reverse connection detection of the live wire and the neutral wire needs to be performed. If the relative error is less than or equal to the preset error value, it indicates that the currently connected power supply is the isolated power supply of the calibration bench, and the reverse connection detection of the live wire and the neutral wire is not performed.
[0006] Preferably, the preset error value is set to five-thousandths. After testing, setting the preset error value to five-thousandths can effectively distinguish between the mains power and the isolated power supply of the calibration bench.
[0007] Based on the above solution, the reverse connection detection of the live wire and the neutral wire is realized through a reverse connection detection circuit.
[0008] Based on the above solution, the live wire and neutral wire detection circuit includes: An induction antenna, which is used as an input end. The first end of the induction antenna is used to detect the electric field signals of the neutral wire and the live wire. The second end of the induction antenna is connected to the first end of the first resistor. The second end of the first resistor is connected to the first end of the second resistor. The second end of the second resistor is grounded; The first end of the first resistor is also connected to the first end of the third resistor. The second end of the third resistor is connected to the first end of the first capacitor. The second end of the first capacitor is grounded. The second end of the third resistor is also connected to the base of the first triode. The collector of the first triode is connected to the digital power supply. The emitter of the first triode is connected to the first end of the fourth resistor. The second end of the fourth resistor is connected to the first end of the second capacitor. The second end of the second capacitor is grounded; The first end of the second capacitor is also connected to the gate of the field effect transistor. The drain of the field effect transistor is connected to the first ends of the fifth resistor and the sixth resistor. The second point of the sixth resistor is connected to the digital power supply. The source of the field effect transistor is grounded; The second end of the fifth resistor is connected to the base of the second triode. The emitter of the second triode is grounded. The collector of the second triode is connected to the first ends of the seventh resistor and the eighth resistor. The second end of the seventh resistor is connected to the digital power supply. The second end of the eighth resistor is the output terminal.
[0009] The second aspect of the present invention also provides a zero - live wire reverse connection detection device, including: A device for obtaining a measured voltage value; A device for converting the measured voltage value into an effective voltage value; A device for calculating the relative error between the effective voltage value and a preset standard voltage; A device for performing zero - live wire reverse connection detection if the relative error is greater than a preset error value.
[0010] The third aspect of the present invention also provides a computer - readable storage medium storing a computer program that can be run. When the computer program runs, it can implement the above - mentioned zero - live wire reverse connection detection method.
[0011] The fourth aspect of the present invention also provides a zero - live wire reverse connection detection watt - hour meter, including: At least one voltage sensor configured to measure the voltage difference across the watt - hour meter; A control unit connected to the voltage sensor, which executes the above - mentioned zero - live wire reverse connection detection method and outputs a detection result; A display device configured to display the detection result of the control unit; A warning device configured to receive the detection result and issue a warning signal if it is a zero - live wire reverse connection.
[0012] Preferably, the watt - hour meter can also be connected to a current sensor.
[0013] The advantages of the present invention are as follows: 1. Adding error judgment before zero - live wire detection eliminates misjudgment in cases where zero - live wire reverse connection detection is not required, ensuring a normal working state. At the same time, when zero - live wire reverse connection detection is needed, it can also accurately judge whether there is a reverse connection; 2. High-precision measurement circuit, adding multiple filters to remove possible interference signals, and cooperating with an error judgment algorithm to ensure the accuracy of error calculation; 3. Improved live-neutral reverse connection detection circuit, which can effectively detect whether the live wire and the neutral wire are reversely connected. By using an induction antenna to capture the electric field signal, and then through steps such as filtering, amplification and logic control, the accurate judgment of the connection state of the live-neutral wire is finally realized, improving the reliability of detection and enhancing the practicability and safety of the system; 4. Wide range of applications, meeting the detection requirements in different scenarios. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is the flowchart of the live-neutral wire detection and judgment of this solution.
[0015] Figure 2 It is the overall flowchart of the live-neutral reverse connection detection of this solution.
[0016] Figure 3 It is the improved live-neutral reverse connection detection circuit of this solution. DETAILED DESCRIPTION OF THE INVENTION
[0017] The following further describes this solution in conjunction with the detailed implementation manners.
[0018] As Figure 1 and Figure 2 shown, for the live-neutral reverse connection detection method provided in this embodiment, system initialization is required before detection; Data acquisition is performed to obtain the voltage AD value; Judge the error between the voltage AD value and the effective voltage value. If the error is less than or equal to 0.5%, the live-neutral reverse connection detection is not performed; if the error is greater than 0.5%, the live-neutral reverse connection detection is performed.
[0019] The formula for calculating the effective voltage value is:
[0020] Where is the effective voltage value, is the value read by the analog-to-digital conversion processor (ADC), is the reference voltage of the ADC, is the resolution of the ADC.
[0021] The formula for calculating the error is:
[0022] Among them, is the standard voltage value output by the calibration table, that is, the preset standard voltage value, is the error.
[0023] In other embodiments, the error is set to any value.
[0024] The detection of the reverse connection of the live wire and the neutral wire is implemented through the reverse connection detection circuit of the live wire and the neutral wire as shown in Figure 2 . If the live wire and the neutral wire are correctly connected, the magnetic field intensity is large at this time, and the MCU detects a square wave; if the live wire and the neutral wire are reversely connected, the magnetic field intensity is small at this time, and the MUC detects a high level; the MCU determines whether the live wire and the neutral wire are reversely connected currently by identifying the output signal.
[0025] As shown in Figure 3 , the reverse connection detection circuit of the live wire and the neutral wire includes: The induction antenna ANTZ1, with the induction antenna ANTZ1 as the input end, its first end is used to detect the electric field signal of the live wire and the neutral wire, the second end is connected to the first end of the resistor RZ6, the second end of the resistor RZ6 is connected to the first end of the resistor RZ8, and the second end of the resistor RZ8 is grounded; The first end of the resistor RZ6 is also connected to the first end of the resistor RZ1, the second end of the resistor RZ1 is connected to the first end of the capacitor CZ1, the second end of the capacitor CZ1 is grounded, the second end of the resistor RZ1 is also connected to the base of the triode QZ1, the collector of the triode QZ1 is connected to the digital power supply, and the emitter of the triode QZ1 is connected to the first end of the resistor RZ4, the second end of the resistor RZ4 is connected to the first end of the capacitor CZ2, and the second end of the capacitor CZ2 is grounded; The first end of the capacitor CZ2 is also connected to the gate of the field effect transistor QZ3, the drain of the field effect transistor QZ3 is connected to the first ends of the resistor RZ7 and the resistor RZ5, the second end of the resistor RZ5 is connected to the digital power supply, and the source of the field effect transistor QZ3 is grounded; The second end of the resistor RZ7 is connected to the base of the triode QZ2, the emitter of the triode QZ2 is grounded, the collector of the triode QZ2 is connected to the first ends of the resistor RZ2 and the resistor RZ3, the second end of the resistor RZ2 is connected to the digital power supply, and the second end of the resistor RZ3 is the output end and is connected to the single-chip microcomputer.
[0026] In other embodiments, the single-chip microcomputer is replaced by other data processing devices, and the data processing device can output a waveform diagram or a data table according to the electric signal at the output end.
[0027] In the above circuit, the induction antenna ANTZ1 captures the electric field signals around the live wire and the neutral wire. Usually, the electric field of the live wire is stronger, and the corresponding induction signal intensity is high, while the electric field of the neutral wire is weaker, and the corresponding induction signal intensity is low. The live wire and the neutral wire are judged according to the high and low of the induction signal intensity.
[0028] Multiple RC filters in the form of "resistor RZ - capacitor CZ" are added to the above circuit, which can remove the possible interference signals in the circuit and ensure high error calculation accuracy.
[0029] In other embodiments, multiple groups of RC filters are added to achieve higher error calculation accuracy.
[0030] In the above circuit, the triode QZ1 is used as an amplifier to send the filtered electrical signal into the triode QZ1 for signal enhancement, facilitating subsequent data processing.
[0031] The field-effect transistor QZ3 in the above circuit is used for switch control. When the gate of the field-effect transistor QZ3 is at a high level, the field-effect transistor QZ3 conducts. When the gate is at a low level, the field-effect transistor QZ3 cuts off. This mechanism is used to generate two states of high and low levels according to the strength of the induction signal.
[0032] In the above circuit, the triode QZ3 is used for output control. When the live wire and the neutral wire are properly connected, the live wire signal captured by the induction antenna ANTZ1 is amplified and then amplified by the triode QZ1 to generate a corresponding level signal. If the base of the triode QZ1 is at a high level, the triode QZ1 will conduct, the gate of the field-effect transistor QZ3 will become high level, the field-effect transistor QZ3 will conduct, the base of the triode QZ2 will become low level, and the triode QZ2 will cut off. At this time, the output terminal outputs a high level. On the contrary, the output terminal outputs a low level. After the data processing device visualizes or digitizes the high and low levels for display, the current connection state of the live wire and the neutral wire can be judged.
[0033] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
[0034] Although the specific implementation manners of the present invention are described above, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solution of the present invention, various modifications or deformations that can be made without creative efforts by those skilled in the art are still within the protection scope of the present invention.
Claims
1. A method for detecting reverse connection of neutral and live wires, characterized in that: The process includes: Get the measured voltage value; Converting the measured voltage value into a voltage effective value; Calculating the relative error between the voltage effective value and a preset standard voltage; If the relative error is greater than the preset error value, a zero-live wire reverse connection detection is performed.
2. A method for detecting reverse connection of neutral and live wires as claimed in claim 1, characterized in that: The preset error value is set to 0.5%.
3. A method for detecting reverse connection of neutral and live wires as claimed in claim 1, characterized in that: The neutral and live wire reverse connection detection is implemented by a reverse connection detection circuit.
4. A method for detecting reverse connection of neutral and live wires as claimed in claim 3, characterized in that: The reverse connection detection circuit comprises: The induction antenna is used as an input end, the first end of the induction antenna is used to detect the electric field signal of the neutral line and the live line, the second end of the induction antenna is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is grounded; The first end of the first resistor is also connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor is grounded, the second end of the third resistor is also connected to the base of the first transistor, the collector of the first transistor is connected to the digital power supply, the emitter of the first transistor is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the second capacitor, and the second end of the second capacitor is grounded; The first end of the second capacitor is also connected to the gate of the field effect tube, the drain of the field effect tube is connected to the first end of the fifth resistor and the first end of the sixth resistor, the second point of the sixth resistor is connected to the digital power supply, and the source of the field effect tube is grounded; The second end of the fifth resistor is connected to the base of the second triode, the emitter of the second triode is grounded, the collector of the second triode is connected to the first end of the seventh resistor and the first end of the eighth resistor, the second end of the seventh resistor is connected to the digital power supply, and the second end of the eighth resistor is the output end.
5. A neutral and live wire reverse connection detection device, characterized in that: include: means for obtaining a measured voltage value; A device for converting the measured voltage value into a voltage effective value; A device for calculating the relative error between the effective value of the voltage and a preset standard voltage; A device for performing zero-live wire reverse connection detection if the relative error is greater than a preset error value.
6. A neutral and live wire reverse connection detection device as claimed in claim 5, characterized in that: The preset error value is set to 0.5%.
7. A method for detecting reverse connection of neutral and live wires as claimed in claim 5, characterized in that: The neutral and live wire reverse connection detection is implemented by a reverse connection detection circuit.
8. A method for detecting reverse connection of neutral and live wires as claimed in claim 7, characterized in that: The reverse connection detection circuit comprises: The induction antenna is used as an input end, the first end of the induction antenna is used to detect the electric field signal of the neutral line and the live line, the second end of the induction antenna is connected to the first end of the first resistor, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is grounded; The first end of the first resistor is also connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor is grounded, the second end of the third resistor is also connected to the base of the first transistor, the collector of the first transistor is connected to the digital power supply, the emitter of the first transistor is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the second capacitor, and the second end of the second capacitor is grounded; The first end of the second capacitor is also connected to the gate of the field effect tube, the drain of the field effect tube is connected to the first end of the fifth resistor and the first end of the sixth resistor, the second point of the sixth resistor is connected to the digital power supply, and the source of the field effect tube is grounded; The second end of the fifth resistor is connected to the base of the second triode, the emitter of the second triode is grounded, the collector of the second triode is connected to the first end of the seventh resistor and the first end of the eighth resistor, the second end of the seventh resistor is connected to the digital power supply, and the second end of the eighth resistor is the output end.
9. A computer-readable storage medium, characterized in that: An executable computer program is stored, and when the computer program is executed, a method for detecting reverse connection of neutral and live wires as claimed in any one of claims 1 to 4 is implemented.
10. A zero-live wire reverse connection detection electric energy meter, characterized in that: include: at least one voltage sensor configured to measure a voltage difference across the electric energy meter; A control unit, connected to the voltage sensor, for executing a neutral-live wire reverse connection detection method as claimed in any one of claims 1 to 4, to output a detection result; a display device configured to display the detection result of the control unit; The warning device is configured to receive the detection result and send out a warning signal if the neutral wire and the live wire are reversely connected.