CN202563077U - Detector for electric energy metering apparatus - Google Patents

Abstract

The utility model relates to a checker for an electric energy metering device, which relates to a checker for the safety and wiring correctness of the electric energy metering device, in particular to an instrument for checking correctness in a power failure state, belonging to the technical field of electrical measurement. It includes a housing, a display screen, buttons, a power supply, a proximity alarm and a control circuit board. A display screen is arranged above the front of the housing, and a button is arranged below the display screen; the proximity alarm is installed in the housing, and the proximity alarm The input end of the device is connected to the power supply; a control circuit board is installed in the casing, and a signal generating circuit, a special test chip for ratio angle difference, a DC impedance testing circuit and a single-chip microcomputer are arranged on the control circuit board, and the input end of the signal generating circuit Connected to the power supply, the signal generating circuit is powered by a battery, the output end of the signal generating circuit is connected to the input end of the special-purpose test chip for ratio angle difference, the output end of the special-purpose test chip for ratio angle difference is connected to the input end of the single-chip microcomputer, and the output end of the single-chip microcomputer is connected to the display screen.

Description

An electric energy metering device inspection instrument

technical field

The utility model relates to a checker for an electric energy metering device, which relates to a checker for the safety and wiring correctness of the electric energy metering device, in particular to an instrument for checking correctness in a power failure state, and belongs to the technical field of electrical measurement.

Background technique

In the process of installation and wiring of metering devices, the professional of power system meter installation and connection needs to check the safety and correctness before power transmission after completion. At present, the means of inspection is limited to using a multimeter to check the continuity of the circuit, and some terminals need to be removed. Not only is the operation cumbersome, but also it is easy to generate uncertain factors in the process of restoring power transmission; at the same time, it has a negative impact on the technical level and cooperation of the measuring personnel. Certain requirements cannot be completely guaranteed in terms of safety and wiring correctness; the most important thing is that the polarity of the transformer, especially the transformation ratio, cannot be verified, and there is a hidden danger of measurement error.

Contents of the invention

The purpose of this utility model is to provide an electric energy metering device inspection instrument for the above shortcomings, using a battery-powered signal source, through a single-chip microcomputer, a special test chip for the ratio angle difference, and using the principle of electromagnetic induction to measure the transformation ratio ratio difference and phase of the transformer. The difference and the continuity of the measured circuit are displayed on the LCD screen, which is intuitive, simple and reliable.       

An electric energy metering device detector is realized by adopting the following technical proposals: an electric energy metering device inspector includes a housing, a display screen, buttons, a power supply, a near-electric alarm and a control circuit board, and a display is arranged above the front of the housing There are buttons below the display screen for function selection and numerical input; the proximity alarm is installed in the housing, and the input end of the proximity alarm is connected to the power supply, and the proximity alarm can realize the electric test function , improve the safety factor during work; a control circuit board is installed in the housing, and a signal generating circuit, a special-purpose test chip for ratio angle difference, a DC impedance testing circuit and a single-chip microcomputer are arranged on the control circuit board, and the input terminal of the signal generating circuit is connected to the single-chip microcomputer. The power supply is connected, the signal generation circuit is powered by a battery, the output end of the signal generation circuit is connected with the input end of the special test chip for the ratio angle difference, the output end of the special test chip for the ratio angle difference is connected with the input end of the single-chip microcomputer, the output end of the single-chip microcomputer is connected with the display The screen is connected; the input terminal of the DC impedance test circuit is connected with the power supply, and the output terminal of the DC impedance test circuit is connected with the input terminal of the single-chip microcomputer. The DC impedance test circuit can be used to test the contact resistance of the loop, and judge the continuity and contact of the loop. Is it good.

Described signal generation circuit adopts sine wave signal generation circuit, and described sine wave signal generation circuit adopts AD9833 signal generator module, what AD9833 signal generator module produces is low power consumption, programmable frequency sine wave, triangular wave and square wave wave shape. The frequency and phase of the output signal are programmable, therefore, the frequency and phase of the output signal can be easily adjusted. No external devices are required. The sine wave signal generating circuit adopts a frequency of 3 KHz-5 KHz, which is used to increase the inductance of the transformer in the circuit to be measured of the metering device, reduce the no-load current of the transformer, and avoid magnetic saturation. It can reduce the output pressure drop loss of the signal generator, make the measured voltage value more stable, and have less distortion, thereby reducing measurement errors.

The sine wave signal generating circuit adopts a low voltage output of about 5V. When used for a multi-winding current transformer, the open circuit or short circuit of other windings will not affect the test results, and it is also applicable to the current transformer using short-circuit compensation. In this way, the conditions of other windings can be ignored during the actual on-site test, which greatly simplifies the operation process.

The special-purpose test chip for ratio angle difference adopts a commercially available AD8302 chip, which is the first single-chip integrated circuit for measuring amplitude and phase difference, and can directly perform phase difference and transformation ratio ratio on two sets of input voltage signals. Poor calculation. The peripheral circuits such as the analog-to-digital conversion and the shaping circuit are saved, the circuit is simplified, the energy consumption is reduced and the calculation accuracy is improved.

The DC impedance testing circuit adopts DC current to pass through the loop to be tested, and calculates U/I by a single-chip computer to obtain the DC resistance of the loop.

The power supply adopts dry batteries or rechargeable batteries.

The display screen adopts a liquid crystal display screen.

Working principle: When an electric energy metering device detector is used for the inspection of the current loop, the signal generating circuit is powered by the power supply, and the signal generating circuit generates a sine wave of about 5V and 3KHz-5 KHz and is connected to the measuring device near the circuit to be tested. One side of the watt-hour meter (a wire needs to be disassembled) and the input terminal of the special test chip for the ratio angle difference. The output terminal of the difference-specific test chip is connected with the single-chip microcomputer, and the transformation ratio difference and the phase difference of the current transformer are calculated by the single-chip computer, and displayed on the display screen.

When an electric energy metering device detector is used for checking a voltage circuit, the signal generating circuit is simultaneously connected to the upper side of the high-voltage fuse of the voltage transformer of the metering device circuit to be tested and the input terminal of a special test chip for the ratio angle difference, The secondary circuit of the voltage transformer near the electric energy meter is connected to the input end of the special test chip for the ratio angle difference; the output end of the special test chip for the ratio angle difference is connected to the single-chip computer, and the transformation ratio difference and phase of the voltage transformer are calculated by the single-chip computer After the difference, it will be displayed on the display.

In the above two inspection processes, the electric inspection function is realized through the near electric alarm, which ensures the safety of the inspectors. The input terminal of the DC impedance test circuit is connected to the power supply, and the output terminal is connected to the input terminal of the single-chip microcomputer and the circuit to be tested of the measuring device at the same time. Whether it is good or not, and the result is displayed on the display.

The utility model has the advantages that a detector for an electric energy metering device has a reasonable design and a simple structure, adopts a single-chip microcomputer as the core, and adopts a display screen to display, which is intuitive, simple and reliable, and has high reliability. The use of battery power supply avoids the cumbersome and unsafe factors of external power supply; the use of near-electrical alarms can realize the electric inspection function and improve the safety factor during work; through the set DC impedance test circuit, the contact resistance of the test circuit can be used to judge the continuity of the circuit. Whether the disconnection and contact are good, to ensure normal inspection work, can measure the on-off and short-circuit conditions of the primary and secondary metering circuits, can roughly judge the contact resistance of the circuit, that is, whether the terminals are tightened, and can realize the electric alarm in the workplace and ensure work safety ;A higher frequency sine wave signal generating circuit is used to increase the inductance of the transformer in the measured metering circuit, reduce the no-load current of the transformer, avoid magnetic saturation, reduce the output voltage drop loss of the signal generator, and make the measured voltage value More stable, less distortion, thereby reducing measurement errors. The sine wave signal generating circuit adopts low-voltage output, and when it is used for a multi-winding current transformer, the open circuit or short circuit of other windings will not affect the test result, and it is also applicable to the current transformer with short-circuit compensation. In this way, the conditions of other windings can be ignored during the actual on-site test, which greatly simplifies the operation process. The special test chip for the ratio angle difference can directly calculate the phase difference and the ratio difference of the transformation ratio for the two sets of input voltage signals. The peripheral circuits such as the analog-to-digital conversion and the shaping circuit are saved, the circuit is simplified, the energy consumption is reduced and the calculation accuracy is improved. The operation is simple, and there is no need to disassemble too many wiring. And the measurement range is large, from the primary fuse to the transformation ratio polarity of the transformer and the secondary impedance, all devices and wiring in the entire metering circuit are included. It greatly simplifies the work and at the same time achieves the purpose of accurately checking the correctness of the electric energy metering device. It is a reliable auxiliary equipment for meter installation and connection work and metering fault identification.

Description of drawings

The utility model will be further described below in conjunction with accompanying drawing:

Fig. 1 is a schematic structural diagram of a detector for an electric energy metering device of the present invention.

Fig. 2 is a block diagram of the test principle of a tester for an electric energy metering device of the present invention.

Figure 3 is a schematic diagram of an electric energy metering device detector of the utility model for current loop inspection.

Figure 4 is a schematic diagram of an electric energy metering device detector of the utility model for voltage circuit inspection.

In the figure: 1. Current transformer, 2. Electric energy metering element, 3. High voltage fuse, 4. Voltage transformer, 5. Housing, 6. Display screen, 7. Button, 8. Electric energy metering device checker.

Detailed ways

Referring to accompanying drawings 1 to 4, an electric energy metering device checker 8 of the present utility model includes a housing 5, a display screen 6, buttons 7, a power supply, a near-electrical alarm and a control circuit board, and a display is arranged above the front of the housing 5. screen 6, buttons 7 are arranged below the display screen 6, and are used for function selection and numerical input; the near-electric alarm is installed in the housing 5, and the input end of the near-electric alarm is connected to the power supply, and the near-electric alarm It can realize the electric inspection function and improve the safety factor during work; a control circuit board is installed in the housing 5, and a signal generating circuit, a special test chip for ratio angle difference, a DC impedance test circuit and a single-chip microcomputer are arranged on the control circuit board, The input end of the signal generation circuit is connected with the power supply, the signal generation circuit is powered by a battery, the output end of the signal generation circuit is connected with the input end of the special test chip for ratio angle difference, and the output end of the special test chip for ratio angle difference is connected with the input end of the single-chip microcomputer , the output of the single-chip microcomputer is connected with the display screen 6; the input of the DC impedance test circuit is connected with the power supply, and the output of the DC impedance test circuit is connected with the input of the single-chip microcomputer, and the DC impedance test circuit can be used to test the contact resistance of the loop , to judge whether the on-off and contact of the circuit are good.

Described signal generating circuit adopts sine wave signal generating circuit, and described sine wave signal generating circuit adopts AD9833 signal generator module, what AD9833 signal generator module produces is low power consumption, programmable frequency sine wave, triangular wave and square wave wave shape. The frequency and phase of the output signal are programmable, therefore, the frequency and phase of the output signal can be easily adjusted. No external devices are required. The sine wave signal generating circuit adopts a frequency of 3 KHz-5 KHz, which is used to increase the inductance of the transformer in the circuit to be measured of the metering device, reduce the no-load current of the transformer, and avoid magnetic saturation. It can reduce the output pressure drop loss of the signal generator, make the measured voltage value more stable, and have less distortion, thereby reducing measurement errors.

The sine wave signal generating circuit adopts a low voltage output of about 5V. When used for a multi-winding current transformer, the open circuit or short circuit of other windings will not affect the test results, and it is also applicable to the current transformer using short-circuit compensation. In this way, the conditions of other windings can be ignored during the actual on-site test, which greatly simplifies the operation process.

The special-purpose test chip for ratio angle difference adopts a commercially available AD8302 chip, which is the first single-chip integrated circuit for measuring amplitude and phase difference, and can directly perform phase difference and transformation ratio ratio on two sets of input voltage signals. Poor calculation. The peripheral circuits such as the analog-to-digital conversion and the shaping circuit are saved, the circuit is simplified, the energy consumption is reduced and the calculation accuracy is improved.

The DC impedance testing circuit adopts DC current to pass through the loop to be tested, and calculates U/I by a single-chip computer to obtain the DC resistance of the loop.

The power supply adopts dry batteries or rechargeable batteries.

Described display screen 6 adopts liquid crystal display screen.

Referring to accompanying drawing 3, when an electric energy metering device detector is used for the inspection of the current loop, the signal generating circuit is powered by the power supply, and the signal generating circuit generates a sine wave of about 5V, 3KHz-5KHz, and the sine wave signal is connected to the current The secondary side of transformer 1 close to the end of the electric energy meter (that is, including the metering circuit wiring, junction box, etc.) and the input end of the special test chip for the ratio angle difference, the primary side of the current transformer 1 and the special test chip for the ratio angle difference The output end of the special test chip for ratio angle difference is connected with the single-chip microcomputer, and after the transformation ratio ratio difference and the phase difference of the current transformer 1 are calculated by the single-chip computer, it is displayed on the display screen 6.

Referring to accompanying drawing 4, when an electric energy metering device detector is used for the inspection of the voltage circuit, the signal generating circuit is simultaneously connected to the upper side of the voltage transformer high-voltage fuse of the metering device to be tested circuit and the special test for the ratio angle difference The input end of the chip, the secondary circuit of the voltage transformer near the electric energy meter end are connected with the input end of the special test chip for the ratio angle difference; After comparing the ratio difference and phase difference, it will be displayed on the display.

In the above two inspection processes, when the battery is turned on, the signal generating circuit generates a sinusoidal AC voltage, and the transformer induces a voltage on the secondary side through the excitation current, and the voltage ratio error is calculated by the special angle difference test chip and the single-chip computer, which is the mutual inductance Transformer ratio error value and transformer phase difference, and infer the on-off and short-circuit conditions of the primary and secondary circuits.

The utility model realizes the electric inspection function through the near electric alarm, which ensures the safety of the inspectors. The input end of the DC impedance test circuit is connected to the power supply, and the output end is connected to the input end of the single-chip microcomputer and the circuit to be tested at the same time. shown on the display.

Claims (8)

1. An electric energy metering device inspection instrument is characterized in that: it comprises a housing, a display screen, buttons, a power supply, an electric alarm and a control circuit board, a display screen is arranged above the front of the housing, and a display screen is arranged below the display screen. button; the proximity alarm is installed in the housing, and the input terminal of the proximity alarm is connected to the power supply; a control circuit board is installed in the housing, and a signal generating circuit and a special test chip for the ratio angle difference are arranged on the control circuit board , DC impedance test circuit and single-chip microcomputer, the input end of the signal generation circuit is connected to the power supply, the signal generation circuit is powered by a battery, the output end of the signal generation circuit is connected to the input end of the special test chip for the ratio angle difference, and the special angle difference test chip The output end is connected with the input end of the single-chip microcomputer, and the output end of the single-chip microcomputer is connected with the display screen; the input end of the DC impedance test circuit is connected with the power supply, and the output end of the DC impedance test circuit is connected with the input end of the single-chip microcomputer. 2. A tester for electric energy metering device according to claim 1, characterized in that: said signal generation circuit adopts sine wave signal generation circuit, and said sine wave signal generation circuit adopts AD9833 signal generator module. 3. An electric energy metering device inspection instrument according to claim 1 or 2, characterized in that: the sine wave signal generating circuit adopts a frequency of 3 KHz-5 KHz. 4. An electric energy metering device inspection instrument according to claim 1 or 2, characterized in that: the sine wave signal generating circuit adopts a low voltage output of about 5V. 5 . The inspection instrument for electric energy metering device according to claim 1 , characterized in that: the special-purpose test chip for the ratio angle difference adopts an AD8302 type chip. 6. The inspection instrument for electric energy metering device according to claim 1, characterized in that: said DC impedance test circuit adopts DC to pass through the circuit to be tested, and calculates U/I by a single-chip microcomputer to obtain the DC resistance of the circuit. 7. An electric energy metering device inspection instrument according to claim 1, characterized in that: said power supply is a dry battery or a rechargeable battery. 8. A tester for electric energy metering device according to claim 1, characterized in that: the display screen is a liquid crystal display screen.

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