JP3151290B2 - Electronic watt-hour meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic watt-hour meter.

[0002]

2. Description of the Related Art A conventional electronic watt-hour meter operates as follows. That is, the power / frequency converter multiplies a voltage signal proportional to the load voltage of the power supply line by a voltage signal proportional to the load current, and obtains a frequency signal proportional to the multiplied signal. This frequency signal is frequency-divided by the frequency division unit and displayed on the display unit as an electric energy. Further, an adjustment unit for adjusting an error of the power / frequency conversion unit is provided. When such an electronic watt-hour meter is subjected to a test, such as confirmation of instrument difference adjustment or measurement, which is one of the manufacturing processes, the test is performed in the manner shown in FIG. In FIG. 3, reference numeral 2 denotes an imaginary load test device for supplying a voltage and a current to be measured to an electronic watt-hour meter;
32, ..., 3n are conventional electronic watt-hour meters, respectively.

The imaginary load test device 2 and the electronic watt-hour meters 30 and 3
, 3n are connected in parallel with the voltage terminals 22, 23 of the imaginary load test device 2 to the voltage input terminals of the electronic watt-hour meters 30, 31, 32,. Current terminal of load test equipment 2
This is performed by connecting the electric power meters 20, 21 in series to the current input terminals of the electric wattmeters 30, 31, 32, ..., 3n. In this way, each of the electronic watt-hour meters 30, 31, 32,
..., and supplies the voltage V ₁ and current I ₁ to 3n. By the way, the frequency signal f output from the power / frequency conversion unit of the electronic wattmeter is represented by v ₁ , a voltage signal proportional to the load voltage of the power supply line, v ₂ , and a phase angle θ. , And the coefficient is represented by the following equation.

[0004]

[Number 1] _{f 1 = k × v 1 ×} v 2 × cosθ The frequency signal f ₁ is divided by the dividing unit, shown on the display unit as the metric value D corresponding to the power. This D is represented by the following equation, where the coefficient is k '.

[0005]

D ₁ = k′f = k × k ′ × v ₁ × v ₂ × cos θ

The imaginary load test device 2 and each electronic watt-hour meter 30,
When the connection of 31, 32, ..., 3n is completed, the electronic watt-hour meter 3
.., 3n with respect to the voltage V ₁ and the current I ₁ supplied from the imaginary load test apparatus 2 so that the measured value matches the measured value D ₁ shown in the equation (2). An instrument error adjustment for operating the device 108 or a test for confirming whether or not the supplied voltage V ₁ and current I are weighed in accordance with the weighed value D ₁ is performed.

[0007]

In such an electronic watt-hour meter, one or several electronic watt-hour meters need to be adjusted or tested in the manufacturing process and then proceed to the next step. In this case, it is impossible to remove only the electronic watt-hour meter after the instrument difference adjustment or the test is completed, because the current circuit supplied from the current terminals 20 and 21 of the imaginary load test device 2 is opened. Normally, when removing the electronic watt-hour meter after the instrumental error adjustment or test is completed, one of the steps is to stop supply of current from the imaginary load test device 2 to prevent the current circuit from being opened, and to perform instrumental error adjustment or test. The electronic watt-hour meter for which the test has been completed is removed and the process is advanced to the next step.
Connect in series to the current terminals 20 and 21 to continue adjustment or test. All electronic watt-hour meters 30, 31, 32,
.., 3n, the current supply from the imaginary load test device 2 is stopped, and all the electronic watt-hour meters 30, 31, 32,. There is also a method. However, in such a method, the work efficiency is extremely poor, such as a delay in progress to the next step, a complicated operation for instrumental difference adjustment or a test.

An object of the present invention is to provide an electronic watt-hour meter capable of adjusting or testing an instrument difference without stopping the imaginary load test apparatus 2 at all and without performing the complicated work of reconnecting the current circuit. Is to do.

[0009]

Means and actions for solving the problems The above object has been achieved.
In order to achieve this, a voltage proportional to the load voltage
A first converting means for converting the signal into a signal,
A second converting means for converting the voltage signal into a proportional voltage signal;
The voltage signal from the conversion means and the voltage signal from the first conversion means
Signal and convert it to a pulse signal corresponding to this multiplied signal.
Electronic wattmeter with power / frequency conversion means
And provided on one input side of the power / frequency conversion means.
Detecting a voltage signal from the first conversion means;First terminal
And provided on the other input side of the power / frequency conversion means,
When desiredFirst terminalConnected to the second conversion means
The voltage signal from the first conversion means is supplied instead of the voltage signal.
Transmit to force / frequency conversion meansSecond terminalConsists of
You.

[0010]

[Function] In such a configuration, when desired (during testing, etc.)
When the first terminal and the second terminal are connected to each other, the second terminal is replaced with the first signal detected at the first terminal instead of the voltage signal from the second conversion means. Since the voltage signal from the first converter is transmitted to the power / frequency converter, the test can be performed using only the voltage signal from the first converter.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an electronic watt-hour meter of the present invention, and FIG. 2 is a diagram showing an instrument difference adjustment or test method of the electronic watt-hour meter of the present invention.

In FIG. 1, reference numeral 100 denotes a voltage input terminal;
Is a current input terminal, and a voltage and a current to be measured are inputted from the voltage input terminal 100 and the current input terminal 101.
The voltage input from the voltage input terminal 100 is
The signal is converted to a voltage signal proportional to the input voltage via the power supply and sent to the power / frequency converter 105. Also, current input terminal 101
The input current is converted through an auxiliary current transformer 101 into a current signal proportional to the input current, and further converted into a voltage signal through a current / voltage conversion unit 104 and output. Sent to

The power / frequency converter 105 includes an auxiliary transformer
The output voltage of 102 is multiplied by the output voltage of current / voltage converter 104, and a frequency signal proportional to the result of the multiplication is output. Here, the frequency of the frequency signal is
It is proportional to the result of multiplying the voltage and current input from the current input terminal 101, that is, the power. Power / frequency converter
The frequency signal output from 105 is frequency-divided by frequency divider 106 and displayed by display 107 as electric energy.

Reference numeral 108 denotes an adjustment unit which adjusts an error caused by a variation in components constituting the electronic watt-hour meter. The adjustment unit adjusts the power / frequency conversion unit 105 to adjust a frequency corresponding to the input power. It is adjusted to be a signal.

Reference numeral 109 denotes a voltage-side signal terminal, which is provided on one input side of the power / frequency converter 105, that is, on the output side of the auxiliary transformer 102, and outputs a voltage signal proportional to the voltage supplied from the voltage input terminal 100. Extraction 110 is a current-side signal terminal, which is provided on the other input side of the power / frequency converter 105, that is, on the output side of the current / voltage converter 104. The current side signal terminal 110 can input a voltage signal to the power / frequency converter 105 when no current is supplied to the current input terminal 101.

Voltage side signal terminal 109 and current side signal terminal
110 are provided at positions where they can be easily short-circuited and opened inside each other.When the product is completed, short-circuiting and opening of the voltage-side signal terminal 109 and the current-side signal terminal 110 cannot be performed. ing. Next, the operation will be described.

When adjusting or testing the instrument difference of the electronic watt-hour meter 1, the voltage-side signal terminal 109 and the current-side signal terminal 110 are short-circuited so that no current is input to the current input terminal 101. When the voltage V ₁ is input to the voltage input terminal 100, the voltage V ₁ is converted by the auxiliary transformer 102 into a voltage signal v ₁ proportional to the voltage V ₁ , and this voltage signal v ₁ is converted into a power / frequency converter 105
And output to the voltage-side signal terminal 109. At this time, the voltage signal v ₁ of the voltage side signal terminal 109 is
Since the voltage-side signal terminal 109 and the current-side signal terminal 110 are short-circuited, input is also performed from the other input side of the power / frequency conversion unit 105. The power / frequency converter 105 multiplies these voltage signals v ₁ , and a frequency f ₂ proportional to the multiplication result, that is,

[0018]

[Equation 3] f_Two= K × v₁× v₁= Kv₁ ^Two  Is output as a frequency signal. Where k is a coefficient
You. Frequency signal f_TwoIs divided by the divider 106, and the frequency
Signal f_TwoD in proportion to_TwoIe

[0019]

(Equation 4) D_Two= K 'x f_Two= K × k ′ × v₁ ^Two  Is displayed on the display unit 107. Where k 'is a coefficient
You.

Normally, since the conversion error of the auxiliary current transformer 103 and the current / voltage converter 104 is so small that it can be ignored, the measured value D of the formula (4) is applied to the voltage V ₁ input to the voltage input terminal 100. ₂ and do to instrumental error adjustment by the adjusting unit 108 to match, also with respect to voltages V ₁ input, whether or not made metric meets the metering value D ₂ of the equation (4) Perform a test to confirm.

More specifically, when adjusting or testing the instrumental error of the electronic watt-hour meter 1, the electronic watt-hour meters 10, 11, 12,... This can be done by supplying only voltage to 1n.
Current terminals 20 and 21 are directly short-circuited to each other.

In such a state, even if any electronic watt-hour meter for which the instrumental error adjustment or the test has been completed is removed,
Since only the voltage circuit connected in parallel is disconnected, the complicated operation of reconnecting the current circuit is not only unnecessary, but the process can proceed to the next step without stopping the imaginary load test device 2. The electronic watt-hour meter for which the instrument error adjustment or the test has not been completed can also continue the instrument error adjustment or the test.

In the case other than the instrumental error adjustment or the test, the voltage side signal terminal 109 and the current side signal terminal 110 are opened (not connected), and the voltage input from the voltage input terminal 110 and the current input terminal 101 is not changed. Measure the amount of current power.

As described above, according to the present invention, when the first terminal and the second terminal are connected at a desired time (during a test or the like), the first terminal is connected to the second terminal .
The second terminal is replaced with the voltage signal from the second conversion means .
A voltage signal from the first conversion means detected at one terminal is transmitted to the power / frequency conversion means, and the voltage signal is converted into a pulse signal proportional to the result of multiplying both voltage signals by the power / frequency conversion means. Therefore, there is no need to input a current during a test or the like, and an electronic watt-hour meter that can improve the workability of a test or the like can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electronic watt-hour meter of the present invention.

FIG. 2 is a diagram showing a system for adjusting or testing an instrument difference of the electronic watt-hour meter of the present invention.

FIG. 3 is a diagram showing a method of adjusting or testing an instrumental difference of a conventional electronic watt-hour meter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electronic watt-hour meter, 100 ... Voltage input terminal, 101 ... Current input terminal, 105 ... Power / frequency conversion part, 109 ... Voltage side signal terminal, 110 ... Current side signal terminal

Claims (1)

(57) [Claims] A first converting means for converting a voltage signal proportional to a load voltage of the power supply line; a second converting means for converting a voltage signal proportional to a load current of the power supply line; An electronic watt-hour meter having power / frequency conversion means for multiplying the voltage signal from the conversion means by the voltage signal from the first conversion means and converting the voltage signal into a pulse signal corresponding to the multiplied signal; A voltage signal from the first conversion means is provided on one input side of the frequency conversion means.
A first terminal provided on the other input side of the power / frequency conversion means, connected to the first terminal when desired and replaced with the first conversion instead of a voltage signal from the second conversion means; And a second terminal for transmitting a voltage signal from the means to the power / frequency conversion means.