CN202929194U - Calibration device for a DC watt-hour meter - Google Patents

Abstract

The utility model provides a calibrating device for a dc electric energy meter, comprising a tested dc electric energy meter, a standard resistor, a control computer, and a dc voltage source, a dc current source, a counter, a digital voltmeter and a DCC (direct current comparator) type current proportioner connected with the control computer respectively. Voltage signals generated by the dc voltage source are connected with the digital voltmeter and the voltage input end of the tested dc electric energy meter in parallel; current signals generated by the dc current source are successively connected with the current input end of the tested electric energy meter and the input end of the DCC type current proportioner in series; the DCC type current proportioner is connected with the digital voltmeter via the standard resistor; and pulse output signals of the tested dc electric meter are input into the counter. The calibrating device can calibrate dc electric meters or dc standard electric meters connected directly or via a mutual inductor, wherein the calibrating range is 0-1200V and 0.1-1000A, and the calibrating result can reach national standard.

Description

Calibration device for a DC watt-hour meter

technical field

The utility model relates to a calibration device, in particular to a DC electric energy meter calibration device.

Background technique

In the 1880s, due to the inconvenience of raising the low voltage of direct current to high voltage for long-distance transmission, the application of direct current was limited and gradually gave way to alternating current. However, with the use of new energy sources, the application of direct current transmission methods and the development of electric vehicles With the promotion, DC power has gradually entered people's sight. Due to the lack of application environment for a long time, DC electric energy measurement has become a blank in the existing traceability field. Theoretically speaking, the measurement of DC electric energy should be easier to realize than the measurement of AC electric energy because it does not need to consider the phase problem. However, because the objects involved in DC electric energy measurement include electric vehicles, new energy power generation and other fields, it also has certain characteristics: DC voltage is not an ideal straight-line output, and there may be pulsating waveforms caused by AC-DC conversion; The DC current and voltage of car charging are relatively large, and this problem needs to be considered in the process of power output, voltage, and current measurement. Therefore, it is necessary to study the DC energy meter calibration device suitable for these new fields.

Utility model content

In order to overcome the deficiencies of the prior art above, the utility model provides a DC electric energy meter calibration device, which can calibrate direct-connected or connected-through transformer-connected DC electric energy meters, DC standard electric energy meters, and the calibration range (0~1200V , 0.1A~1000A), the calibration results can be traced to the national standard.

In order to achieve the above object, the utility model takes the following scheme:

A DC electric energy meter calibration device is provided, the device includes a measured DC electric energy meter, a standard resistance, a control computer and a DC voltage source, a DC current source, a counter, a digital voltmeter and a DC comparison instrument respectively connected to the control computer Current proportional device; the voltage signal generated by the DC voltage source is connected in parallel to the voltage input terminal of the digital voltmeter and the measured DC electric energy meter, and the current signal generated by the DC current source is connected in series to the measured Measure the current input terminal of the DC watt-hour meter and the input terminal of the DC comparison formula current scaler, the DC comparison formula current scaler is connected to the digital voltmeter through the standard resistance, and the pulse of the measured DC power meter is The output signal is input to the counter.

The current signal output by the direct current source is scaled down by the direct current comparator current scaler.

The current output range of the direct current source is 0.1A˜1000A, and the voltage output range of the direct voltage source is 0V˜1100V.

The DC comparison ritual current scaler scales down the current signal, and the scale accuracy is less than 5×10 ^-6 .

The output signal of the DC comparator current scaler is changed into a voltage signal through the standard resistance, and the digital voltmeter measures the voltage signal.

The digital voltmeter is an eight-and-a-half-digit digital voltmeter, and the measurement accuracy is less than 10×10 ^-6 .

The standard resistance is a first-class standard resistance, and its annual stability is less than 2×10 ^-6 .

Compared with the prior art, the utility model has the beneficial effects that: the utility model utilizes a DC comparison ritual current ratio standard to greatly increase the calibration current range, improve the measurement accuracy, use a computer for control, and improve the automation of the calibration process The device can be used to calibrate direct-connected or transformer-connected DC watt-hour meters and DC standard watt-hour meters. The calibration value can be traced to the highest national standard; the device is simple and reliable, and has high stability.

Description of drawings

Figure 1 is a schematic diagram of the structure of the DC electric energy meter calibration device.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

As shown in Fig. 1, the utility model provides a kind of DC watt-hour meter calibration device, and described device comprises measured DC watt-hour meter, standard resistance, control computer and through GPIB bus and the direct current voltage source that connects with described control computer respectively, direct current source , a counter, a digital voltmeter, and a DC comparison ceremony current scaler; the digital voltmeter includes a digital voltmeter A and a digital voltmeter B, and the voltage signal generated by the DC voltage source is connected in parallel to the digital voltmeter A and the Measure the voltage input terminal of the DC electric energy meter, the current signal generated by the DC current source is connected in series to the current input terminal of the measured DC electric energy meter and the input terminal of the DC comparison ceremony current scaler, and the DC comparison The ritual current scaler is connected to the digital voltmeter B through the standard resistance, and the pulse output signal of the measured DC electric energy meter is input into the counter.

The current signal output by the direct current source is scaled down by the direct current comparator current scaler.

The current output range of the direct current source is 0.1A˜1000A, and the voltage output range of the direct voltage source is 0V˜1100V.

The DC comparison ritual current scaler scales down the current signal, and the scale accuracy is less than 5×10 ^-6 . The DC comparator is based on the magnetic modulation DC comparator: it converts the measured current and the output current of the driven power supply into a magnetic quantity related to the current, and compares it indirectly. That is, the fixed winding Ns and the variable winding Nx are wound on the iron core, and the currents Is and Ix flow through them respectively. The magnetic potentials generated by them on the iron core are equal in value and opposite in direction, that is, the ampere-turn balance, IsNs=IxNx. When the magnetic potential is unbalanced, the signal is detected by the magnetic flux detector, and the current value of the driven power supply is automatically controlled to make the ampere-turn equal. The method has high accuracy, good stability, and no strict requirements on ambient temperature and power supply voltage.

The output signal of the DC comparator current scaler is changed into a voltage signal through the standard resistance, and the digital voltmeter measures the voltage signal.

Both the digital voltmeter A and the digital voltmeter B are eight-and-a-half-digit digital voltmeters, and the measurement accuracy is less than 10×10 ^-6 .

The standard resistance is a first-class standard resistance, and its annual stability is less than 2×10 ^-6 .

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and not to limit them. Although the present utility model has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: it is still possible Any modification or equivalent replacement made to the specific implementation of the present utility model without departing from the spirit and scope of the present utility model shall be covered by the claims of the present utility model.

Claims (7)

1. direct current energy meter calibrating installation is characterized in that: described device comprises tested direct current energy meter, measuring resistance, control computing machine and the direct voltage source, DC current source, counter, digital voltmeter and the dc comparator formula current ratio device that are connected respectively with described control computing machine; The voltage input end of the voltage signal that described direct voltage source the produces described digital voltmeter of access in parallel and described tested direct current energy meter, the current signal series connection that described DC current source produces accesses the current input terminal of described tested direct current energy meter and the input end of described dc comparator formula current ratio device successively, described dc comparator formula current ratio device connects described digital voltmeter by described measuring resistance, the described counter of pulse output signals input of described tested direct current energy meter.

2. direct current energy meter calibrating installation according to claim 1 is characterized in that: the current signal of described DC current source output carries out ratio by described dc comparator formula current ratio device to be dwindled.

3. direct current energy meter calibrating installation according to claim 1, it is characterized in that: the electric current output area of described DC current source is 0.1A～1000A, the voltage range of described direct voltage source output is 0V～1100V.

4. direct current energy meter calibrating installation according to claim 1, it is characterized in that: described dc comparator formula current ratio device carries out ratio to current signal to be dwindled, and the ratio accuracy is less than 5 * 10 ^-6

5. direct current energy meter calibrating installation according to claim 4, it is characterized in that: described dc comparator formula current ratio device output signal becomes voltage signal through described measuring resistance, and described digital voltmeter is measured described voltage signal.

6. direct current energy meter calibrating installation according to claim 1, it is characterized in that: described digital voltmeter is eight Semi-digital voltage tables, and accuracy of measurement is less than 10 * 10 ^-6

7. direct current energy meter calibrating installation according to claim 1, it is characterized in that: described measuring resistance is First class standard resistance, its year, stability was less than 2 * 10 ^-6

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