Detector for judging whether wiring of electric energy metering device is correct or wrong

Abstract

The invention provides a detector for judging whether wiring of an electric energy metering device is correct or wrong. The detector comprises a signal source module, a detection module, a micro control unit (MCU), a display module, a power supply module and a correction sensor. The signal source module generates analog voltage and current signals under the condition that the electric energy metering device is not electrified, and simulates the operation state of a power grid. The detection module is connected with voltage and current input ends of the electric energy metering device, and the MCU controls the signal source module, collects response signals, analyzes and processes the response signals and judges whether wiring is correct or wrong. The correction sensor provides a current direction reference signal. According to the detector, wiring detection can be carried out under uncharged and charged conditions, and the detection accuracy and the working efficiency are improved.

Description

Technical Field

[0001] The invention relates to the technical field of electric energy metering, and in particular to a detection instrument for determining the correctness of wiring of an electric energy metering device. Background Art

[0002] Electricity metering is mainly used for trade settlement of electricity commodities and assessment of internal economic and technical indicators of enterprises. Its accuracy is directly related to the economic interests of power generation enterprises, power supply enterprises and electricity users. The installation of electricity metering devices, as an important part of metering work, is an important link in the production and operation management of power enterprises and the safe operation of power grids. Its technology, skill level and management level are not only related to the development of the power industry and the image of power enterprises, but also affect the fairness, justice, accuracy and reliability of electricity trade settlement. Due to differences in work skills and business levels or negligence of on-site staff, the secondary metering line of the energy meter may be connected incorrectly, the polarity may be reversed or the phase may be broken, which will not only bring economic losses but also easily cause personal safety.

[0003] At present, the following two methods are mainly used to check the installation of electric energy metering:

[0004] The first is to use instruments for testing, such as volt-ampere phase meter, electric energy meter field tester, electric energy metering fault error detector, etc. The premise of these detection methods is that the site has been powered and has a certain load. At the same time, the technical requirements of the installers are relatively high, and the on-site operation is relatively complicated. Therefore, most of the on-site installers do not use instruments for measurement. The second is to use a multimeter (or a pass light) to align the wires, which can determine the continuity of the wires, but cannot determine the polarity. It is time-consuming and laborious, and there are secondary wiring errors, which requires a high level of technical skills of the personnel.

[0005] Since there are hundreds of thousands of wiring errors in the electric energy metering device, wiring errors are prone to occur. The above two methods have great limitations. First, the skills required for people are relatively high and there are certain safety risks. Second, it is complicated and time-consuming. Third, due to technical reasons, it is impossible to conduct a comprehensive inspection, such as the inability to determine the polarity of the mutual inductor and the inlet and outlet lines of the current loop. Therefore, it is impossible to use the instrument to perform wiring detection when there is no power or no load. Fourth, since there is strong electricity on the wiring detection terminal of the electric energy metering device, the danger is increased and it is easy to cause personal safety problems. Summary of the invention

[0006] The object of the present invention is to provide a detection instrument for determining the correctness of wiring of an electric energy metering device, so as to improve the accuracy and work efficiency of equipment detection and wiring verification by on-site personnel.

[0007] To achieve the above-mentioned purpose, the present invention provides a detection instrument for determining the correctness of wiring of an electric energy metering device, comprising: a signal source module, a detection module, an MCU, a display module, a power supply module and a correction sensor;

[0008] The signal source module is used to generate analog voltage signals and analog current signals when the electric energy metering device is not powered, so as to simulate the operating state of the actual power grid so as to detect the electric energy metering device;

[0009] The detection module comprises a voltage connection terminal and a current connection terminal, wherein the voltage connection terminal is used to connect to a voltage input terminal of an electric energy metering device, and the current connection terminal is used to connect to a current input terminal of the electric energy metering device;

[0010] The MCU is used to control the signal source module to generate an analog voltage signal and an analog current signal when the electric energy metering device is not powered, and connect the analog voltage signal and the analog current signal to the electric energy metering device through the voltage connection terminal and the current connection terminal, and collect the voltage signal and the current signal responded by the electric energy metering device through the detection module, and analyze and process the voltage signal and the current signal to determine whether the wiring of the electric energy metering device is correct;

[0011] The MCU is also used to directly connect the analog voltage signal and the analog current signal to the electric energy metering device through the voltage connection terminal and the current connection terminal when the electric energy metering device is energized, and collect the voltage signal and the current signal of the electric energy metering device through the detection module, and analyze and process the voltage signal and the current signal to determine whether the wiring of the electric energy metering device is correct;

[0012] The power supply module is used to convert the external power supply into the working voltage required by each module inside the detector;

[0013] The correction sensor is used to provide a current direction reference signal for the analysis and processing of the MCU.

[0014] Preferably, the voltage connection terminals include A-phase voltage connection terminals, B-phase voltage connection terminals, C-phase voltage connection terminals and N-phase voltage connection terminals, and the current connection terminals include A-phase current connection terminals, B-phase current connection terminals and C-phase current connection terminals, and each phase current connection terminal includes a positive connection terminal and a negative connection terminal.

[0015] Preferably, the MCU is specifically used to compare the analog voltage signal and analog current signal generated by the signal source module with the voltage signal and current signal responded by the electric energy metering device when the electric energy metering device is not powered, and determine the on / off, phase, phase sequence and current direction of the electric energy metering device according to the comparison result.

[0016] Preferably, the MCU is specifically used to determine, when the electric energy metering device is energized, that any phase voltage circuit is disconnected if the detected voltage value of any phase voltage signal of the electric energy metering device is close to zero or below a preset threshold; and to determine that any phase current circuit is disconnected if the current value of any phase current signal is close to zero or below a preset threshold.

[0017] Preferably, the MCU is specifically used to obtain waveform data of a three-phase voltage signal or waveform data of a three-phase current signal when the electric energy metering device is energized, analyze the phase difference of the three-phase voltage signal or the three-phase current signal according to the waveform data, and determine whether there is a phase error and a phase sequence error according to the phase difference.

[0018] Preferably, the MCU is specifically used to obtain the current direction of the current signal when the electric energy metering device is energized. If the measured current direction is consistent with the current direction reference signal of the calibration sensor, the current wiring is correct; if not, the current wiring is wrong.

[0019] The electric energy metering device wiring correctness determination detector proposed by the present invention has the following beneficial effects:

[0020] The present invention can judge whether the wiring is correct when the electric energy metering device is not energized, thereby improving the safety of on-site detection; by simulating the actual operation state of the power grid, the wiring condition of the electric energy metering device can be accurately detected, thereby improving the accuracy of detection; the present invention has a live detection function, is adaptable to different working environments, and improves the adaptability of detection; the equipment has high integration and is easy to operate, which helps to improve the work efficiency of on-site personnel; the use of a correction sensor further improves the accuracy of analysis and avoids misjudgment due to incorrect current direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0022] Figure 1 The present invention is a circuit diagram of a detection instrument for determining whether wiring of an electric energy metering device is correct or incorrect.

[0023] Figure 2 The present invention is a schematic diagram of the appearance of a detection instrument for determining whether wiring of an electric energy metering device is correct or incorrect.

[0024] Markings in the figure:

[0025] 1-Function selection key, 2-Start button, 3-Confirm button, 4-Display unit, 5-Connector, 6-Signal line terminal block, 7-Shielded cable, 8-Current sensor, 9-Signal lead, 10-Connector. DETAILED DESCRIPTION

[0026] The detailed description of the drawings is intended as an illustration of the current embodiment of the present application, and is not intended to represent the only form in which the present application can be implemented. It should be understood that the same or equivalent functions can be accomplished by different embodiments intended to be included in the spirit and scope of the present application.

[0027] See also Figure 1 , an embodiment of the present invention provides a detection instrument for determining the correctness of wiring of an electric energy metering device, comprising: a signal source module, a detection module, an MCU, a display module, a power supply module and a correction sensor;

[0028] The signal source module is used to generate analog voltage signals and analog current signals when the electric energy metering device is not powered, so as to simulate the operating state of the actual power grid so as to detect the electric energy metering device;

[0029] The detection module comprises a voltage connection terminal and a current connection terminal, wherein the voltage connection terminal is used to connect to a voltage input terminal of an electric energy metering device, and the current connection terminal is used to connect to a current input terminal of the electric energy metering device;

[0030] The MCU is used to control the signal source module to generate an analog voltage signal and an analog current signal when the electric energy metering device is not powered, and connect the analog voltage signal and the analog current signal to the electric energy metering device through the voltage connection terminal and the current connection terminal, and collect the voltage signal and the current signal responded by the electric energy metering device through the detection module, and analyze and process the voltage signal and the current signal to determine whether the wiring of the electric energy metering device is correct;

[0031] The MCU is also used to directly connect the analog voltage signal and the analog current signal to the electric energy metering device through the voltage connection terminal and the current connection terminal when the electric energy metering device is energized, and collect the voltage signal and the current signal of the electric energy metering device through the detection module, and analyze and process the voltage signal and the current signal to determine whether the wiring of the electric energy metering device is correct;

[0032] The power supply module is used to convert the external power supply into the working voltage required by each module inside the detector;

[0033] The correction sensor is used to provide a current direction reference signal for the analysis and processing of the MCU.

[0034] Specifically, when the electric energy metering device is not powered, the signal source module is activated to generate analog voltage signals and analog current signals. These analog signals are designed according to the operating status of the actual power grid and can simulate the changes in voltage and current in the power grid, thereby providing a test condition similar to the actual working environment for the electric energy metering device. When the analog voltage and current signals generated by the signal source module are connected to the electric energy metering device through the voltage connection terminal and the current connection terminal of the detection module, the detection module can collect the response of the electric energy metering device to the analog voltage and current signals.

[0035] The working principle of MCU (micro control unit) is as follows:

[0036] De-energized detection: The MCU controls the signal source module to generate analog signals, and connects these signals to the electric energy metering device through the connection terminals of the detection module. Then, the MCU collects the voltage and current signals responded by the electric energy metering device and analyzes and processes them. By comparing the analog signal with the response signal, the MCU can determine whether the wiring of the electric energy metering device is correct.

[0037] Live detection: When the electric energy metering device is energized, the MCU can directly collect the voltage and current signals of the electric energy metering device through the connection terminals of the detection module. Similarly, the MCU analyzes and processes these signals to determine whether the wiring is correct.

[0038] The MCU's analysis and processing includes logical judgment of the wiring method, comparison of signal phases, current direction, etc., to determine the correctness of the wiring.

[0039] The correction sensor provides a reference signal of the current direction to the MCU. When analyzing and processing the current signal, the MCU will refer to the signal of the correction sensor to ensure that the judgment of the current direction is accurate.

[0040] In summary, the embodiment of the present invention simulates the grid signal and collects the response signal of the electric energy metering device, combines the reference signal of the correction sensor, and performs analysis and processing by the MCU, so as to accurately determine whether the wiring of the electric energy metering device is correct, and can perform effective detection regardless of whether it is energized or not.

[0041] Furthermore, the voltage connection terminals include A-phase voltage connection terminals, B-phase voltage connection terminals, C-phase voltage connection terminals and N-phase voltage connection terminals, and the current connection terminals include A-phase current connection terminals, B-phase current connection terminals and C-phase current connection terminals, and each phase current connection terminal includes a positive connection terminal and a negative connection terminal.

[0042] Specifically, if Figure 2As shown, the three connection terminals, namely, the A-phase voltage connection terminal, the B-phase voltage connection terminal, and the C-phase voltage connection terminal, are respectively used to connect the three-phase voltage input terminals of the electric energy metering device. In a three-phase AC system, the A, B, and C phases are voltage sources spaced 120 degrees apart from each other, and they represent different phases of the three-phase power supply. The N-phase voltage connection terminal is used to connect the neutral line (also called the zero line). In a three-phase four-wire system with a grounded neutral point, the N-phase voltage connection terminal is used to provide a voltage reference to the ground.

[0043] The three connection terminals, A-phase current connection terminal, B-phase current connection terminal, and C-phase current connection terminal, are used to connect the three-phase current input terminals of the electric energy metering device, corresponding to the voltage terminals, and are used to measure the current flowing through each phase. Each phase current connection terminal includes a positive and a negative connection terminal, which is to be able to distinguish the direction of the current. In the measurement of current, it is very important to know the direction of the current flow, because the direction of the current will affect the measurement of electric energy and the correctness of the wiring. The design of these connection terminals enables the detector to adapt to three-phase four-wire or three-phase three-wire electric energy metering devices. In a three-phase system, it is crucial to correctly distinguish and connect the voltage and current of each phase, because incorrect wiring will lead to inaccurate electric energy measurement and even damage the equipment.

[0044] like Figure 2 As shown, press the start button 2 and the system automatically performs detection according to the selected function. Select the function confirmation button 3 to select whether to detect with power on. The connector 5 is used to connect the shielded cable 7, and plugging and unplugging can be started. The shielded cable 7 has the function of transmitting current and reducing interference. The signal line terminal block 6 is used for plug-in quick wiring. The high-precision clamp current sensor 8 is used to collect current and current correction to make the measurement more accurate. The signal lead 9 is used to transmit current or voltage. The terminal 10 (banana head) is used in conjunction with the clip to connect to the terminal of the electric energy metering device.

[0045] Furthermore, the MCU is specifically used to compare the analog voltage signal and analog current signal generated by the signal source module with the voltage signal and current signal responded by the electric energy metering device when the electric energy metering device is not powered, and determine the on / off, phase, phase sequence and current direction of the electric energy metering device according to the comparison result.

[0046] Specifically, the analog voltage signal and analog current signal generated by the signal source module are pre-set to simulate the voltage and current waveforms under normal grid conditions. The analog voltage signal is input to the corresponding voltage input terminal of the electric energy metering device through the A-phase, B-phase, and C-phase voltage connection terminals, and the analog current signal is input to the corresponding current input terminal of the electric energy metering device through the positive and negative poles of the A-phase, B-phase, and C-phase current connection terminals. After receiving the analog signal, the electric energy metering device will generate corresponding voltage and current response signals. The detection module collects these response signals and transmits the data to the MCU for processing. The comparative analysis is as follows:

[0047] On / off judgment: MCU compares the input analog signal with the collected response signal. If the response signal exists, it means the circuit is on; if the response signal does not exist, it means the circuit is off.

[0048] Phase determination: MCU analyzes whether the phase of the response signal is consistent with the phase of the input analog signal. If they are consistent, the phase is correct; if they are inconsistent, there is a phase error;

[0049] Phase sequence determination: The MCU checks whether the phase sequence of the A, B, and C three-phase response signals is consistent with the phase sequence of the input analog signal. In a three-phase system, the correctness of the phase sequence is crucial to the accuracy of electric energy measurement.

[0050] Current direction determination: The MCU uses the reference signal provided by the calibration sensor to determine whether the response signals of the positive and negative poles of the current connection terminals conform to the expected current direction. If the current direction is opposite to the expected direction, it indicates that there is an error in the wiring.

[0051] Determination result output: Based on the results of the above comparison and analysis, the MCU outputs the determination result through the display module to inform the operator whether the wiring of the electric energy metering device is correct and the specific problem (such as on / off, phase, phase sequence or current direction error).

[0052] Through this comparison and judgment process, the MCU can effectively detect the wiring status of the electric energy metering device to ensure that all wiring is correct before actual power-on operation, thereby improving the accuracy of electric energy metering and the safety of the system.

[0053] Furthermore, the MCU is specifically used to determine that any phase voltage circuit is disconnected if the voltage value of any phase voltage signal of the electric energy metering device detected is close to zero or below a preset threshold when the electric energy metering device is energized; and to determine that any phase current circuit is disconnected if the current value of any phase current signal is close to zero or below a preset threshold.

[0054] Specifically, when the electric energy metering device is powered, the MCU (microcontroller unit) detects and determines whether the voltage and current circuits are disconnected through the following steps:

[0055] Collecting live signals: When the electric energy metering device is in a live state, the MCU controls the detection module to collect the voltage signal and current signal of the electric energy metering device in real time. The collected signals include the voltage signals of phase A, phase B, and phase C and the corresponding current signals.

[0056] Voltage signal analysis: The MCU analyzes each phase voltage signal collected and checks its voltage value. If the voltage value of any phase voltage signal is close to zero or lower than a preset threshold (this threshold is set according to the voltage range when the circuit is working normally), the MCU will make the following judgments:

[0057] Disconnection judgment: If the voltage value is too low, it indicates that the phase voltage circuit is disconnected, because under normal working conditions, the voltage of each phase should be maintained within a relatively stable range.

[0058] Current signal analysis: At the same time, the MCU also analyzes the collected current signals of each phase and checks its current value. If the current value of any phase current signal is close to zero or lower than a preset threshold (this threshold is set according to the current range when the circuit is working normally), the MCU will make the following judgments:

[0059] Disconnection judgment: If the current value is too low, it indicates that the phase current circuit is disconnected, because under normal working conditions, the current of each phase should be maintained in a relatively stable range, and even under light load conditions, the current value will not be close to zero.

[0060] Result output: Based on the above analysis, the MCU outputs the judgment result through the display module to inform the operator which phase of the voltage or current line is disconnected.

[0061] Through this detection method, even when powered, the MCU can effectively detect the wiring status of the electric energy metering device, ensure the normal operation of the electric energy metering device, and promptly discover potential wiring problems, thereby improving the reliability and safety of the system.

[0062] Furthermore, the MCU is specifically used to obtain waveform data of a three-phase voltage signal or a three-phase current signal when the electric energy metering device is energized, analyze the phase difference of the three-phase voltage signal or the three-phase current signal according to the waveform data, and determine whether there is a phase error and a phase sequence error according to the phase difference.

[0063] Specifically, when the electric energy metering device is energized, the MCU (microcontroller unit) analyzes the phase difference of the three-phase voltage signal or the three-phase current signal through the following steps to determine whether there is a phase error and a phase sequence error:

[0064] Waveform data acquisition: The MCU controls the detection module to collect the waveform data of the three-phase voltage signal and / or three-phase current signal in the energized state in real time. The waveform data contains detailed information about the change of voltage or current over time, which is crucial for analyzing the phase relationship.

[0065] Waveform data analysis: MCU processes the collected waveform data and calculates the phase difference of the three-phase voltage signal or the three-phase current signal. The phase difference refers to the time delay or leading relationship between the three-phase signals. In an ideal three-phase AC system, the phase difference of the three-phase voltage or current should be 120 degrees.

[0066] Phase difference calculation: By analyzing the peak or zero-crossing point of the waveform data, the MCU can determine the phase position of each phase voltage or current. The calculation of the phase difference usually involves comparing the time delays between the three-phase signals. For example, if the A phase signal leads the B phase signal in time, and the B phase signal leads the C phase signal, and each phase difference is close to 120 degrees, the phase sequence is correct.

[0067] Phase error determination: If the calculated phase difference is not equal to 120 degrees, or the phase relationship does not conform to the order of phase A leading phase B, and phase B leading phase C, the MCU will determine that there is a phase error. The phase error may be caused by a wiring error or an internal problem in the energy metering device.

[0068] Phase sequence error determination: If the phase relationship of the three-phase signal does not conform to the correct phase sequence (for example, phase A leads phase C, and phase C leads phase B), the MCU will determine that there is a phase sequence error. Phase sequence error is usually caused by incorrect phase sequence connection during wiring.

[0069] Result output: Based on the analysis results of the phase difference, the MCU outputs the judgment results of whether there is a phase error and phase sequence error through the display module.

[0070] Through this method of analyzing phase difference, the MCU can accurately detect the phase and phase sequence of the electric energy metering device in the energized state, thereby improving the detection efficiency and accuracy of the wiring of the electric energy metering device.

[0071] Furthermore, the MCU is specifically used to obtain the current direction of the current signal when the electric energy metering device is energized. If the measured current direction is consistent with the current direction reference signal of the calibration sensor, the current wiring is correct; if not, the current wiring is wrong.

[0072] Specifically, when the electric energy metering device is energized, the MCU (microcontroller unit) obtains the current direction of the current signal and determines whether the current wiring is correct through the following steps:

[0073] Current direction reference signal acquisition: The calibration sensor provides a known current direction reference signal, which represents the correct current direction and is usually achieved through a current sensor with a known direction.

[0074] Current signal acquisition: The MCU controls the detection module to collect the current signals in the energized state in real time. These signals are input to the detection module through the current connection terminals (including the positive and negative connection terminals of phase A, phase B, and phase C).

[0075] Current direction analysis: The MCU analyzes the collected current signal to determine its current direction. This usually involves detecting the zero crossing point of the current signal and determining whether the current flows from the positive electrode to the negative electrode or vice versa.

[0076] Current direction comparison: The MCU compares the measured current direction with the current direction reference signal provided by the calibration sensor. If the measured current direction is consistent with the reference signal, it means that the current wiring is correct, that is, the positive and negative poles of the current are consistent with the direction defined by the reference signal. If the measured current direction is inconsistent with the reference signal, it means that there is an error in the current wiring, and the positive and negative poles may be connected in reverse.

[0077] Result output: Based on the comparison results of the current direction, the MCU outputs whether the current wiring is correct or not through the display module. If the current wiring is wrong, the MCU can also provide specific error information, such as which phase of the current wiring is wrong, so that the operator can quickly locate and correct the problem.

[0078] Through this detection method, the MCU can accurately determine the correctness of the current wiring in the live state, which is crucial to ensure the accurate measurement of the energy metering device and the safe operation of the system. The use of the correction sensor improves the reliability of the detection and avoids misjudgment caused by the wrong current direction.

[0079] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A detection instrument for determining the correctness of wiring of an electric energy metering device, characterized in that: include: Signal source module, detection module, MCU, display module, power module and calibration sensor; The signal source module is used to generate analog voltage signals and analog current signals when the electric energy metering device is not powered, so as to simulate the operating state of the actual power grid so as to detect the electric energy metering device; The detection module comprises a voltage connection terminal and a current connection terminal, wherein the voltage connection terminal is used to connect to a voltage input terminal of an electric energy metering device, and the current connection terminal is used to connect to a current input terminal of the electric energy metering device; The MCU is used to control the signal source module to generate an analog voltage signal and an analog current signal when the electric energy metering device is not powered, and connect the analog voltage signal and the analog current signal to the electric energy metering device through the voltage connection terminal and the current connection terminal, and collect the voltage signal and the current signal responded by the electric energy metering device through the detection module, and analyze and process the voltage signal and the current signal to determine whether the wiring of the electric energy metering device is correct; The MCU is also used to directly connect the analog voltage signal and the analog current signal to the electric energy metering device through the voltage connection terminal and the current connection terminal when the electric energy metering device is energized, and collect the voltage signal and the current signal of the electric energy metering device through the detection module, and analyze and process the voltage signal and the current signal to determine whether the wiring of the electric energy metering device is correct; The power supply module is used to convert the external power supply into the working voltage required by each module inside the detector; The correction sensor is used to provide a current direction reference signal for the analysis and processing of the MCU.

2. The detector according to claim 1, characterized in that: The voltage connection terminals include A-phase voltage connection terminals, B-phase voltage connection terminals, C-phase voltage connection terminals and N-phase voltage connection terminals, and the current connection terminals include A-phase current connection terminals, B-phase current connection terminals and C-phase current connection terminals, and each phase current connection terminal includes a positive connection terminal and a negative connection terminal.

3. The detector according to claim 2, characterized in that: The MCU is specifically used to compare the analog voltage signal and analog current signal generated by the signal source module with the voltage signal and current signal responded by the electric energy metering device when the electric energy metering device is not powered, and determine the on / off, phase, phase sequence and current direction of the electric energy metering device according to the comparison result.

4. The detector according to claim 2, characterized in that: The MCU is specifically used to determine that any phase voltage circuit is disconnected if the voltage value of any phase voltage signal of the electric energy metering device detected is close to zero or below a preset threshold when the electric energy metering device is energized; If the current value of any phase current signal is close to zero or lower than a preset threshold, it is determined that the current line of any phase is disconnected.

5. The detector according to claim 4, characterized in that: The MCU is specifically used to obtain waveform data of a three-phase voltage signal or a three-phase current signal when the electric energy metering device is energized, analyze the phase difference of the three-phase voltage signal or the three-phase current signal according to the waveform data, and determine whether there is a phase error and a phase sequence error according to the phase difference.

6. The detector according to claim 4, characterized in that: The MCU is specifically used to obtain the current direction of the current signal when the electric energy metering device is energized. If the measured current direction is consistent with the current direction reference signal of the calibration sensor, the current wiring is correct; if not, the current wiring is wrong.

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