JPH06300792A - Automatic regulator for electronic watthour meter - Google Patents

Abstract

PURPOSE:To accurately regulate an error of an electronic watthour meter in a short time. CONSTITUTION:Power to be output from a power generation source 2 is supplied to both a master meter 3 and a meter 5 to be regulated, a measured electric energy measured by the meter 5 to be regulated is compared with reference electric energy measured by the meter 3 by an error calculator 56, an error of both the electric energies is calculated, an amplifier 54 is so controlled by an amplifier controller 58 as to eliminate the error, and so error-regulated that the measured electric energy of the meter 5 to be regulated becomes equal to the reference electric energy measured by the meter 3.

Description

Detailed Description of the Invention

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic adjustment device for an electronic watt-hour meter that automatically adjusts the error in the measured power of the electronic watt-hour meter.

[0003]

2. Description of the Related Art An error measurement in an electronic watt hour meter is
The comparison method called RC method is adopted. In this method, as shown in FIG. 2, the power generated from the power generation source 2 is supplied to both the meter 1 to be adjusted and the master meter 3 adjusted by another highly sensitive measuring device. It Adjusted meter 1 and master meter 3
Measures the power and outputs a metering pulse and a reference pulse, which are proportional to the power, respectively. The metering pulse from the adjusted meter 1 and the reference pulse from the master meter 3 are counted by the adjusted meter counter 42 and the master meter counter 41 of the RC counter 4, respectively, for a predetermined period. The RC counter 4 is the counter 4 for the meter to be adjusted.
2 and the counter value of the master meter counter 41 are displayed, both count display values are calculated according to the following formulas, and the count display value of the metering pulse of the adjusted meter 1 with respect to the count display value of the reference pulse of the master meter 3 is displayed. Calculate the error of.

Error (%) = (metering pulse display value−reference pulse display value) × 100 / (reference pulse display value) (1) In this method, the accuracy of the master meter 3 affects the measurement accuracy. The power generation source 2 does not need high precision and high stability, and the generated power may vary.

FIG. 3 is a block diagram showing a circuit configuration of the adjusted meter 1. In the figure, the current and voltage components of the power to be measured are the current transformer (CT) 11 respectively.
And a signal proportional to the current value and voltage value detected by the transformer (PT) 12 is converted. The signal from the current transformer 11 and the signal from the transformer 12 via the variable resistor 17 are multiplied by the power-frequency (W / F) converter 13 and converted into a pulse number proportional to the multiplication value. This pulse signal is frequency-divided by the frequency divider 14 to an appropriate frequency, and then output to the RC counter 4 via the output unit 18 and counted by the counter 15, and the count value is displayed on the display unit. The measured electric energy is displayed at 16.

In order to adjust the meter to be adjusted 1 thus constructed by the RC method, after the first error measurement, the RC is adjusted.
An error is calculated from the displayed value of the counter 4, and the variable resistor 1 connected to the output of the transformer 12 is based on this error.
After adjusting 7 manually, perform the error measurement again, check that the error is within the specified range, and if it is out of the specified range, repeat the adjustment and error measurement and check that the error is within the specified range. We are working to make adjustments after confirming that there is something.

[0007]

In the above-mentioned conventional method, since the error is eliminated while the variable resistor is manually adjusted, the adjustment takes time and labor, which is inefficient and uneconomical. There is a problem.

The present invention has been made in view of the above,
An object of the invention is to provide an automatic adjustment device for an electronic watt-hour meter, which can accurately perform error adjustment of the electronic watt-hour meter in a short time.

[Constitution of Invention]

[0010]

In order to achieve the above object, an automatic adjusting device for an electronic watt hour meter according to the present invention is a power-voltage converting means for converting the power to be measured into a voltage and the power-voltage converting means. An electric watt-hour meter having a voltage-frequency conversion means for converting the voltage from the means into a frequency and outputting the frequency, the electric power being generated, converting the power into a voltage, and then converting the frequency into a frequency, and outputting the frequency. Generating means and electric power output from the electric power generating means are supplied to the electric power-voltage converting means and the voltage-frequency converting means to convert the frequency into a frequency, and the frequency is compared with a frequency output from the electric power generating means. The gist of the present invention is to have a comparing means for calculating the difference between the two frequencies and an adjusting means for adjusting the voltage output from the power-voltage converting means based on the difference between the frequencies from the comparing means.

[0011]

In the automatic adjusting device for the electronic watt hour meter of the present invention,
The electric power output from the electric power generation means is supplied to the electric power-voltage conversion means and the voltage-frequency conversion means to be converted into a frequency, and this frequency is compared with the frequency output from the electric power generation means to calculate the difference between the two frequencies. Then, the voltage output from the power-voltage conversion means is adjusted based on this difference.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an automatic adjustment device for an electronic watt hour meter according to an embodiment of the present invention. The automatic adjustment device for the electronic watt hour meter shown in FIG.
The power generation source 2 and the master meter 3 which are the same as those shown in FIG. 2 and the adjusted meter 5 which is the electronic watt-hour meter for which the error is to be adjusted, and the power generated from the power generation source 2 is the master meter 3 and the adjusted meter. 5 are supplied to both. The power generation source 2 does not require special accuracy and stability, and the master meter 3 is adjusted by another high-accuracy measuring device.

The adjusted meter 5 supplies the current component and the voltage component of the power to be measured from the power generation source 2 to the current transformer (CT) 51 and the transformer (PT) 52, respectively, and the current value and the voltage thereof, respectively. The signal is converted into a signal proportional to the value and supplied to the power-voltage (W / V) converter 53. In addition,
The variable resistor as shown in FIG. 3 is not connected to the output of the transformer 52, but the automatic adjustment device for the electronic watt hour meter does not require adjustment of the variable resistor as in the conventional case. .

The power-voltage converter 53 includes a current transformer 51.
Is multiplied by a signal proportional to the current value from the transformer 52, and the output signal is multiplied by the amplifier 54.
Supply to. The amplifier 54 is a power-voltage converter 53.
Is amplified and supplied to the voltage-frequency (V / F) converter 55. The voltage-frequency converter 55 converts the output voltage of the amplifier 54 into a pulse signal having a corresponding pulse number, and supplies this pulse signal as a weighing pulse signal to the counter 59 and the error calculator 56. The counter 59 counts the metering pulse signal output from the voltage-frequency converter 55, and displays the counting result as the amount of electric power on the display unit 50.

On the other hand, the master meter 3 measures the electric power supplied from the electric power generation source 2, converts it into a reference pulse signal having a pulse number proportional to the amount of electric power, and supplies it to the error calculation unit 56 of the adjusted meter 5. Supply.

The error calculator 56 compares the metering pulse signal supplied from the voltage-frequency converter 55 of the meter 5 to be adjusted with the reference pulse signal supplied from the master meter 3 to determine the difference between the two pulse signals. That is, the error between the reference pulse signal representing the amount of power measured by the master meter 3 and the metering pulse signal representing the amount of power measured by the meter 5 to be adjusted is calculated as shown in the above-mentioned formula (1), and this calculation is performed. The error signal thus stored is stored in the error data storage unit 57.

The error data storage unit 57 supplies the stored error signal to the amplifier control unit 58. The amplifier control unit 58 controls the amplification degree of the amplifier 54 according to the supplied error signal, whereby the pulse signal output from the voltage-frequency converter 55 becomes equal to the pulse signal from the master meter 3, That is, the measured power amount of the adjusted meter 5 becomes equal to the reference power amount of the master meter 3, and the error between the two power amounts calculated by the error calculator 56 is eliminated. The error data storage unit 57 is composed of, for example, an EEPROM or the like so that the stored error signal is not erased due to a power failure or the like.

In this way, the error between the two electric power amounts is eliminated, and the voltage-frequency converter 5 representing the measured electric power amount of the adjusted meter 5 which becomes equal to the reference electric power amount of the master meter 3.
The pulse signal from 5 is counted by the counter 59 and displayed on the display unit 50 as the amount of power adjusted accurately.

More specifically, for example, if the reference pulse display value measured by the master meter 3 is 100 and the metering pulse display value measured by the adjusted meter 5 is 95, the error between them is -5%. However, in order to cancel this error, the error data storage unit 57 converts 5% of the error into a binary code or the like, and supplies the value of this binary code to the amplifier control unit 58. The amplifier control unit 58 has this 2
For example, a ladder resistance in the amplifier 54 is selected by the binary code (that is, a resistance value that gives an amplification factor of 100/95 = 1.05 times is selected), thereby canceling the error of 5%. Control. The amplifier control unit 58 may be composed of a non-inverting amplifier such as an operational amplifier, and its feedback resistance may be selected.

Although the above-described embodiment is mainly composed of hardware, it may be replaced with software to have the same structure. In this case, for example, the error calculation unit 56, the error data storage unit 57, the amplifier control unit 58, the counter 5
9. The display unit 50 and the like can be composed of one microcomputer and peripheral circuits.

Further, the amplifier control section 58 is
Instead of selecting the feedback resistance of the non-inverting amplifier composed of the operational amplifier, the feedback resistance of the inverting amplifier may be selected and the output thereof may be inverted at the amplification ratio of 1: 1.

Further, when the master meter 3 has a known error, the error of the master meter 3 may be set in the error calculator 56 to cancel it.

[0024]

As described above, according to the present invention,
The electric power output from the electric power generation means is supplied to the electric power-voltage conversion means and the voltage-frequency conversion means to be converted into a frequency, and this frequency is compared with the frequency output from the electric power generation means to calculate the difference between the two frequencies. However, since the voltage output from the power-voltage conversion means is adjusted based on this difference, the complicated work of manually adjusting the variable resistor as in the conventional case is unnecessary, and the adjustment cost and the adjustment time are reduced. In addition, it is possible to prevent work mistakes and improve efficiency and economy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an automatic adjustment device for an electronic watt hour meter according to an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional automatic adjustment device for an electronic watt hour meter.

FIG. 3 is a configuration diagram of an electronic watt-hour meter used in the automatic adjustment device for the electronic watt-hour meter in FIG.

[Explanation of symbols]

 2 power generation source 3 master meter 5 adjusted meter 53 power-voltage converter 54 amplifier 55 voltage-frequency converter 56 error calculation unit 57 error data storage unit 58 amplifier control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaharu Takeda 70 Yanagimachi, Sachi-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi factory

Claims (1)

[Claims] 1. Power for converting power to be measured into voltage-
An electronic watt hour meter having voltage-frequency conversion means for converting the voltage from the voltage conversion means and the power-voltage conversion means into a frequency and outputting the frequency, wherein the power is generated and the power is converted into a voltage. To a frequency and output the converted power to the frequency, and the power output from the power generation means
Comparing means for supplying the voltage converting means and the voltage-frequency converting means to convert it into a frequency, comparing the frequency with the frequency output from the power generating means and calculating the difference between the two frequencies, and the comparing means. And an adjusting unit that adjusts the voltage output from the power-voltage converting unit based on the difference in the frequency of the automatic adjusting device for an electronic watt hour meter.