Single-phase electric energy meter neutral current field measurement device

Abstract

The utility model relates to a single-phase electric energy meter neutral line current on-site measuring device, which belongs to the field of on-site rapid detection of electric energy meter metering, is arranged on site, and amplifies signals accessed by an electric energy meter neutral line input access end through an operational amplifier. And the amplified signal is transmitted to the intelligent terminal through the analog quantity acquisition module, so that the current value of the neutral line of the electric energy meter can be recorded in real time. The device can be connected with a neutral line of a three-phase four-wire electric energy meter, can continuously record the current value of the neutral line of the electric energy meter for a long time, does not need a worker to hold a clamp meter for measurement, can continuously record the current value of the neutral line at night, and solves the problem that the clamp meter cannot be used for long-time measurement. Therefore, the electricity stealing behavior can be better monitored.

Description

Technical Field

[0001] The utility model belongs to the field of on-site rapid detection of electric energy meter measurement, and specifically relates to an on-site measurement device for neutral line current in a single-phase electric energy meter. Background Art

[0002] Electricity is the most widely used energy in modern society and an indispensable part of people's lives today. The demand for electricity is growing, leading to a continuous increase in electricity consumption. As a result, the problem of electricity theft has emerged. The theft of electricity is concealed, dispersed and diversified, which will bring a lot of hidden dangers to the normal power supply and electricity safety. Therefore, it is urgent to crack down on the theft of electricity.

[0003] Traditional means of electricity theft, such as under-current theft and under-voltage theft, are gradually disappearing due to the popularity of smart meters. New methods of electricity theft are more covert. Existing technology often uses a clamp meter to measure the neutral line current. The clamp meter test principle is to measure the current through magnetic induction. Therefore, the detection effect for small currents is not ideal and the error is large. In addition, due to the concealment of electricity theft, long-term monitoring is required, and the clamp meter cannot detect electricity theft for a long time. Utility Model Content

[0004] The utility model aims to provide a field measuring device for neutral line current in a single-phase electric energy meter, so as to solve the problem that a clamp meter cannot monitor the neutral line current for a long time.

[0005] In order to solve the above technical problems, the utility model provides a field measurement device for the neutral line current in a single-phase electric energy meter, including a power module, a neutral line input access terminal of the electric energy meter, an operational amplifier, an analog quantity acquisition module and an intelligent terminal, wherein the power module is used to supply power to the operational amplifier and the analog quantity acquisition module; the neutral line input access terminal of the electric energy meter is connected to the same-direction input terminal of the operational amplifier so as to amplify the signal of the neutral line input access terminal of the electric energy meter through the operational amplifier; the output terminal of the operational amplifier is connected to the intelligent terminal through the analog quantity acquisition module so as to transmit the amplified signal to the intelligent terminal.

[0006] Furthermore, the power supply module includes a transformer, a first rectifier module, a second rectifier module, a positive voltage regulator block and a negative voltage regulator block; the primary side of the transformer is used to connect alternating current; the first secondary side of the transformer is connected to the input end of the first rectifier module, and the output end of the first rectifier module outputs a positive voltage through the output end of the positive voltage regulator block; the second secondary side of the transformer is connected to the input end of the second rectifier module, and the output end of the second rectifier module outputs a negative voltage through the negative voltage regulator block; the output positive voltage is used to power the analog quantity acquisition module, and the output positive voltage and negative voltage are used to power the analog quantity acquisition module.

[0007] Furthermore, the first rectifier module and the second rectifier module are both rectifier bridges.

[0008] Furthermore, capacitors are provided between the common terminal and the output terminal of the positive voltage stabilizing block and the negative voltage stabilizing block.

[0009] Furthermore, the intelligent terminal has an interface for connecting to a clamp meter to obtain measurement data of the clamp meter.

[0010] The beneficial effects of the above technical solution are as follows: the utility model is an improved invention, and the measuring device of the utility model is arranged on site. The signal received at the neutral line input access terminal of the electric energy meter is amplified by using an operational amplifier, and the amplified signal is transmitted to the intelligent terminal through the analog quantity acquisition module, thereby realizing real-time recording of the neutral line current value of the electric energy meter. The utility model can be used to connect to the neutral line of a three-phase four-wire electric energy meter, and record the neutral line current value of the electric energy meter for a long time without interruption. The staff does not need to hold a clamp meter for measurement, and the neutral line current value can be continuously recorded at night, which solves the problem that the clamp meter cannot be used for long-term measurement, so that the theft of electricity can be better monitored. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a general structural diagram of an embodiment of a neutral line current field measuring device in a single-phase electric energy meter of the utility model;

[0012] Figure 2 It is a circuit diagram for detecting the neutral line current in an electric energy meter of an embodiment of the neutral line current field measuring device in a single-phase electric energy meter of the utility model;

[0013] Figure 3 It is a connection diagram of a clamp meter in an embodiment of a field measurement device for neutral current in a single-phase electric energy meter of the utility model;

[0014] Figure 4 The utility model discloses a connection diagram of a neutral line in an electric energy meter according to an embodiment of a neutral line current field measuring device for a single-phase electric energy meter.

[0015] 1. AC power interface; 2-1. Fixing screw; 2-2. Fixing screw; 2-3. Fixing screw; 2-4. Fixing screw; 3. Current clamp input interface; 4. Intelligent terminal; 5. Analog quantity acquisition module; 6. Neutral line input terminal of electric energy meter; S1. Current clamp; S2. Connecting wire; S3. Current clamp interface; S4. Single-phase electric energy meter; S5. Neutral line incoming terminal. DETAILED DESCRIPTION

[0016] The utility model focuses on providing a field measurement device for the neutral line current in a single-phase electric energy meter, including a power module, a neutral line input access terminal of the electric energy meter, an operational amplifier, an analog quantity acquisition module and an intelligent terminal, wherein the power module is used to supply power to the operational amplifier and the analog quantity acquisition module; the neutral line input access terminal of the electric energy meter is connected to the same-direction input terminal of the operational amplifier, so as to amplify the signal of the neutral line input access terminal of the electric energy meter through the operational amplifier; the output terminal of the operational amplifier is connected to the intelligent terminal through the analog quantity acquisition module, so as to transmit the amplified signal to the intelligent terminal. The measurement device of the utility model is arranged on site, and the signal received by the neutral line input access terminal of the electric energy meter is amplified by using the operational amplifier, and the amplified signal is transmitted to the intelligent terminal through the analog quantity acquisition module, thereby realizing real-time recording of the neutral line current value of the electric energy meter. The utility model can be used to connect to the neutral line of a three-phase four-wire electric energy meter, and the neutral line current value of the electric energy meter is recorded for a long time without interruption, without the need for the staff to hold the clamp meter for measurement, and the neutral line current value can be continuously recorded at night, which solves the problem that the clamp meter cannot be used for long-term measurement, so that the electricity theft behavior can be better monitored.

[0017] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] Embodiment of the on-site measurement device for neutral current in a single-phase electric energy meter:

[0019] Under normal circumstances, the phase line current and neutral line current of a single-phase energy meter are equal, otherwise it is called shunt abnormality. Since the single-phase energy meter S4 measures energy based on the phase line current, when the phase line current of the single-phase energy meter is less than the neutral line current, the energy measured by the energy meter will become smaller. There are many reasons for the shunt abnormality of the single-phase energy meter S4, the most common of which are incorrect wiring of the energy meter and electricity theft by unlawful users. The basic method for measuring the neutral line current is: select a suitable test point at the outlet end of the single-phase energy meter S4 to measure the single-phase energy meter current value and the neutral line current value respectively, and evaluate whether the neutral line current is within the normal range.

[0020] In the process of residential electricity use, there are some disadvantages in the on-site test of neutral current, mainly including the following aspects:

[0021] Safety risks: Neutral current testing generally uses a clamp meter, where the on-site inspector holds the clamp meter to clamp the cable or wire that needs to be measured, and ensures that the jaws are clamped tightly without missing anything. Since the clamp meter must be used under power, there are certain safety risks, which may lead to safety accidents such as electric shock.

[0022] Measurement accuracy problem: The principle of clamp meter testing is to measure current through magnetic induction. Therefore, the detection effect for small current is not ideal and the error is large. In actual operation, it is difficult to completely close the jaws of the clamp meter, which can easily cause errors. In addition, external factors such as electromagnetic interference can also affect the measurement results.

[0023] Preventing electricity theft: On-site real-time monitoring of neutral line current is an effective means to prevent electricity theft. Since the supervision is usually less strict at night, most electricity theft occurs at night. On-site inspection personnel holding the clamp meter for a long time will cause hand fatigue, thus affecting the accuracy of the inspection.

[0024] Therefore, there is an urgent need for a neutral line field detection device that can provide more accurate and reliable measurement results and is suitable for different detection scenarios.

[0025] A single-phase electric energy meter neutral line current field measurement device of the present embodiment includes a power module, an electric energy meter neutral line input access terminal, an operational amplifier OP, a fixing screw 2-1, a fixing screw 2-2, a fixing screw 2-3, a fixing screw 2-4, an analog quantity acquisition module 5, an intelligent terminal 4 and an electric energy meter neutral line input terminal 6, wherein the power module is used to supply power to the operational amplifier OP and the analog quantity acquisition module 5; the electric energy meter neutral line input access terminal is connected to the same direction input terminal of the operational amplifier OP, so as to amplify the signal of the electric energy meter neutral line input access terminal through the operational amplifier OP; wherein the operational amplifier reverse input terminal is provided with a 1kΩ resistor, the operational amplifier same direction input terminal is provided with a 0.05Ω resistor, the operational amplifier output terminal is connected to the operational amplifier reverse input terminal through an 18kΩ resistor and a 2kΩ potentiometer, and the 1kΩ resistor, the 18kΩ resistor, and the 2kΩ potentiometer cooperate to realize the setting of the operational amplifier amplification factor, and the operational amplifier factor is: Assuming that the maximum center line current is 10A, the maximum output voltage of the neutral line is: 0.5Ω×10A=0.5V, 0.5V×20=10V; the operational amplifier power supply end is also provided with a 0.1F capacitor for filtering. The operational amplifier uses the LF411I model operational amplifier. Fixing screws 2-1, 2-2, 2-3 and 2-4 are used to fix the neutral line current field measurement device in the single-phase electric energy meter.

[0026] The output end of the operational amplifier OP is connected to the intelligent terminal 4 through the analog quantity acquisition module 5, so as to transmit the amplified signal to the intelligent terminal 4. Figure 1 and Figure 2 shown.

[0027] Among them, the power supply module includes a mains interface 1, a transformer T1, a first rectifier module BR1, a second rectifier module BR2, a positive voltage regulator block IC1 and a negative voltage regulator block IC2; the mains interface 1 is used to access AC power, the primary side of the transformer T1 is used to connect AC power, and the transformer T1 is used to convert high voltage into low voltage; the first secondary side of the transformer T1 is connected to the input end of the first rectifier module BR1, and the output end of the first rectifier module BR1 outputs a positive voltage through the output end of the positive voltage regulator block IC1, which is used to convert AC power into DC power; the second secondary side of the transformer T1 is connected to the input end of the second rectifier module BR2, and the output end of the second rectifier module BR2 outputs a negative voltage through the negative voltage regulator block IC2, and the first rectifier module BR1 and the second rectifier module BR2 are both used to convert AC power into DC power; the output end of the positive voltage regulator block IC1 is connected to the analog quantity acquisition module 5 for power supply. Among them, the first rectifier module BR1 and the second rectifier module BR2 are both rectifier bridges. The common end of the positive voltage regulator block IC1 and the negative voltage regulator block IC2 is connected to the output end through a capacitor.

[0028] The on-site measurement device for the neutral current in the single-phase electric energy meter also includes a clamp meter, which is connected to the intelligent terminal 4 via the current clamp input interface 3. The clamp meter includes a current clamp S1, a connecting line S2 and a current clamp interface S3. The current clamp S1 is connected to the current clamp interface S3 via the connecting line S2. The current clamp interface S3 is connected to the current clamp input interface 3, and is used to transmit the detection data of the current clamp S1 to the intelligent terminal 4. Specifically, Figure 3 As shown. The clamp meter can quickly detect the neutral line current value to determine whether there is a possibility of wrong wiring or power theft. According to the on-site situation, if it is a wrong wiring, it can be corrected directly. If there is a suspicion of power theft and long-term monitoring and recording of the detection results are required, it is necessary to connect a neutral line field detection device to continuously record the neutral line current value in the electric energy meter. The neutral line field detection device is connected to the neutral line input terminal S5 of the single-phase electric energy meter S4 through the neutral line input terminal 6 of the electric energy meter. Figure 4 As shown. Finally, the neutral current field measurement device in the single-phase electric energy meter can accurately measure large currents and eliminate the influence of electromagnetic interference. By combining the clamp meter and the neutral current field measurement device, a neutral current field measurement device for a single-phase electric energy meter is designed to achieve complementary advantages. This combination can greatly improve the detection function of the neutral current in the single-phase electric energy meter and prevent electricity theft.

[0029] Specific implementation methods are given above, but the present invention is not limited to the described implementation methods. The basic idea of ​​the present invention is the above basic scheme. For ordinary technicians in this field, according to the teachings of the present invention, it does not require creative labor to design various deformed models, formulas, and parameters. Changes, modifications, substitutions, and variations of the implementation methods without departing from the principles and spirit of the present invention still fall within the scope of protection of the present invention.

Claims

1. A field measurement device for neutral current in a single-phase electric energy meter, characterized in that: It includes a power module, a neutral line input access terminal of an electric energy meter, an operational amplifier, an analog quantity acquisition module and an intelligent terminal. The power module is used to supply power to the operational amplifier and the analog quantity acquisition module; the neutral line input access terminal of the electric energy meter is connected to the same-direction input terminal of the operational amplifier so as to amplify the signal of the neutral line input access terminal of the electric energy meter through the operational amplifier; the output terminal of the operational amplifier is connected to the intelligent terminal through the analog quantity acquisition module so as to transmit the amplified signal to the intelligent terminal.

2. The on-site measurement device for neutral current in a single-phase electric energy meter according to claim 1, characterized in that: The power module includes a transformer, a first rectifier module, a second rectifier module, a positive voltage stabilizing block and a negative voltage stabilizing block; the primary side of the transformer is used to connect to alternating current; the first secondary side of the transformer is connected to the input end of the first rectifier module, and the output end of the first rectifier module outputs a positive voltage through the output end of the positive voltage stabilizing block; the second secondary side of the transformer is connected to the input end of the second rectifier module, and the output end of the second rectifier module outputs a negative voltage through the negative voltage stabilizing block; the output positive voltage is used to power the analog quantity acquisition module, and the output positive voltage and negative voltage are used to power the analog quantity acquisition module.

3. The on-site measurement device for neutral current in a single-phase electric energy meter according to claim 2, characterized in that: The first rectifier module and the second rectifier module are both rectifier bridges.

4. The on-site measurement device for neutral current in a single-phase electric energy meter according to claim 2, characterized in that: Capacitors are arranged between the common terminal and the output terminal of the positive voltage stabilizing block and the negative voltage stabilizing block.

5. The on-site measurement device for neutral current in a single-phase electric energy meter according to claim 1, characterized in that: The intelligent terminal has an interface for connecting with the clamp meter to obtain measurement data of the clamp meter.

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