JP4193697B2 - Electronic energy meter and power calculation circuit - Google Patents

Description

The present invention relates to a power calculating circuit for calculating the power from the current and voltage current was converted to an electronic energy meter and de Ijitaru value metering the amount of power to A / D conversion and voltage.

  In FIG. 22, 1 is an electronic watt-hour meter, 21 is a current transformer, 22 is a transformer, 23 is a current A / D converter for A / D converting the input current into a digital value proportional to the input current, 24 Is a voltage A / D converter that converts an input voltage into a digital value proportional to the input voltage, 25 is an adjustment start switch, 31 is an adjustment value of the balance adjustment register 42, and an A / D conversion value of the voltage A / D converter 24 32 is a power adjustment multiplier for multiplying the output proportional to the current of each phase of the current A / D converter 23 and the output proportional to the voltage of each phase of the voltage A / D converter 24, respectively. Is an adder, 34 is a digital low-pass filter, 35 is a light load adjustment adder for adding adjustment values of a light load adjustment register, 36 is an accumulator, 37 is a register, 38 is a magnitude comparator, and 39 is a magnitude. Counter for adding the output pulses from the-menu de comparators 38, 40 is a display for displaying the amount of power is an integrated result of the counter 39.

Reference numeral 41 denotes a phase adjustment register (shift register) that stores a phase adjustment value, 42 a balance adjustment register that stores a balance adjustment value, 43 a light load adjustment register that stores a light load correction value, and 44 stores a rated reference value. It is a rated reference value register.
45 is a CPU for calculating the adjustment value, 46 is a calculation control unit including the CPU 45, 47 is a communication I / F for controlling the test power supply device 56, 48 is an EPROM, 51 is a power supply switching device, and 52 is The control CPU 53 is a timer, 54 is a ROM, 55 is a communication I / F, 56 is a power supply switching device 51, control CPU 52, timer 53, ROM 54, communication I / F 55, and imaginary load test power supply 60 used for adjustment. This is a test power supply device.

Adjustment of the conventional electronic watt-hour meter is performed by the following method.
(1) First, each adjustment initial value stored in advance in the EPROM 48 is set in the phase adjustment register 41, the balance adjustment register 42, the light load adjustment register 43, and the rated reference value register 44.
(2) Next, the rated load adjustment for coarse adjustment is performed.
The CPU 45 controls the test power supply device 56 via the communication I / F 47 and applies power having a rated voltage, a rated current, and a power factor of 1.0 to all phases. The count value W0 of the counter 39 at that time is compared with the rated constant pulse value WK (set value) set in the rated reference value register 44 in (1), and the comparison value D = W0 / WK is centered at 1.0. It is determined whether it is within the predetermined range. Since it is rough adjustment, the predetermined range is wider than a predetermined range at the time of full adjustment described later. When the contrast value D is outside the predetermined range, the set value WK of the rated reference value register 44 is repeatedly changed until the contrast value D is within the predetermined range. This is called rough adjustment of the rated load.

(3) Next, balance adjustment is performed.
Hereinafter, one of the three phases is referred to as an A phase, a B phase, and a C phase, respectively.
First, the B phase balance is adjusted. The CPU 45 controls the test power supply device 56 via the communication I / F 47, applies a rated voltage, a rated current, and a power factor of 1.0 to only the A phase, measures the power for a certain time, and within a certain time. The count value WA of the counter 39 is stored. Next, power of rated voltage, rated current, and power factor of 1.0 is applied only to the B phase, the power for a certain time is measured, and the count value WB is stored in the same manner. WA and WB are compared to determine whether or not the comparison value E = WB / WA is within a predetermined range centered at 1.0. If the contrast value E is out of the predetermined range, the B-phase balance adjustment value set in the balance adjustment register 42 is varied in the direction of 1.0 and is repeated until it is within the predetermined range.

Next, C-phase balance adjustment is performed. Power of rated voltage, rated current, and power factor of 1.0 is applied only to phase C, the power for a certain time is measured, and the count value WC is stored in the same manner. Thereafter, the balance adjustment of the C phase is performed in the same manner as the balance adjustment of the B phase.
(4) Next, full adjustment is performed.
The CPU 45 controls the test power supply device 56 via the communication I / F 47, applies power of rated voltage, rated current and power factor of 1.0 to all phases, measures the power for a fixed time, and counts the counter within the fixed time. A count value W0 of 39 is stored. The count value W0 is compared with the rated constant pulse value WK (set value) set by (1), and it is determined whether or not the contrast value F = W0 / WK is within a predetermined range centered at 1.0. When the contrast value F is outside the predetermined range, rough adjustment of the rated load is performed by repeatedly changing the set value WK of the rating reference value register 44 until the contrast value F is within the predetermined range.

(5) Next, phase adjustment is performed.
First, phase adjustment of the A phase is performed. The CPU 45 controls the test power supply device 56 via the communication I / F 47, applies a rated voltage, a rated current, and a power factor of 0.5 to only the A phase, measures the power for a certain time, and within a certain time. The count value WA of the counter 39 is stored. Then, a comparison is made with the power factor constant pulse value WPK set in (1), and it is determined whether or not the comparison value G = WPK / WA is within a predetermined range centered at 1.0. When the contrast value G is outside the predetermined range, the phase adjustment value of the A phase of the phase adjustment register 41 is varied in the direction of 1.0, and is repeated until it is within the predetermined range, and the number of shift stages at that time is set. .

Next, phase adjustment of the B phase is performed. Power of rated voltage, rated current, and power factor of 0.5 is applied only to the B phase, the power for a fixed time is measured, and the count value WB is stored in the same manner. Thereafter, the phase adjustment of the B phase is performed in the same manner as the phase adjustment of the A phase.
Next, phase adjustment of the C phase is performed. Power of rated voltage, rated current, and power factor of 0.5 is applied only to phase C, the power for a certain time is measured, and the count value WC is stored in the same manner. Thereafter, the phase adjustment of the C phase is performed in the same manner as the phase adjustment of the A phase.

  In the electronic watt-hour meter as described above, phase and amplitude errors have occurred with respect to the voltage and voltage of the power supply line due to the difference in phase and amplitude characteristics of the current transformer 21 and transformer 22. In order to eliminate this error and accurately measure the amount of power, the phase and amplitude are adjusted by a dedicated custom chip, and a general-purpose external A / D converter cannot be used.

  Further, since the phase adjustment is performed by delaying the data acquisition timing of the voltage A / D converter 24 in terms of time, that is, by the number of shift stages of the phase adjustment register 41, the transformer 21 or the variable having a large output phase shift with respect to the input. When the flow device 22 is used, a large number of shift stages of the phase adjustment register 41 are required, that is, a large number of shift registers are required. Since the shift register is configured by H / W (hardware), the chip area is increased by the number of stages. As the circuit becomes larger and the power consumption increases and the time for delaying the timing becomes longer, there is a problem that the error from the true value of the frequency and amplitude other than the phase increases and the measurement accuracy deteriorates.

Further, since the phase shift is adjusted according to the number of shift stages, it is necessary to use the current transformer 21 and the transformer 22 in which the phase shift falls within the shift stage number. A transformer 22 was required.
In addition, since the resolution of phase adjustment depends on the number of shift stages, a custom chip incorporating a large number of shift stages or an A / D converter with a high sampling frequency is required to increase the resolution.

  For error adjustment of electronic watt-hour meter, first input rated voltage, rated current and power factor of 1.0 to all phases, then perform full adjustment coarse adjustment, then balance adjustment for each phase. Input the rated voltage, rated current, and power factor of 1.0 for each phase, adjust the balance for each phase in turn, and then input the rated voltage, rated current, and power factor of 1.0 for all phases. Full adjustment, and finally phase adjustment, input the rated voltage, rated current, power of power factor 0.5, and it is necessary to adjust each phase in turn in the same way. It was. Further, when it is desired to extremely change the meter constant of the electronic wattmeter 1 to be adjusted, since the initial value of the threshold value of the magnitude comparator 38 is constant, it takes more time for rough adjustment to be performed first. .

Further, in the conventional example, when a reactive power amount measuring function is added, it is necessary to further input an electric power having a rated voltage, a rated current, and a power factor of 0.0 to adjust an error.
Further, in the above adjustment method, the balance adjustment and the phase adjustment are performed in a pseudo manner for each phase regardless of whether the cause of the balance deviation is a voltage circuit or a current circuit so that the amount of power as output is correct. The balance is adjusted by multiplying the output of the voltage conversion circuit by a coefficient, and the phase is adjusted by virtually delaying the conversion timing of the voltage conversion circuit of each phase regardless of whether the cause of phase shift is the voltage circuit or the current circuit. Since it was adjusted, the electronic watt-hour meter could not be provided with a function of accurately measuring the voltage and current of each phase.

The present invention has been made to solve such a problem, and an electronic watt-hour meter and power that have high measurement accuracy of electric power or electric energy and can widely cope with phase and amplitude deviations of current transformers and transformers. An object is to provide an arithmetic circuit.
Another object of the present invention is to provide an electronic watt-hour meter with a short error adjustment time and an error adjustment method thereof.

An electronic watt-hour meter according to the present invention A / D converts a voltage transformed by a transformer into a digital value and A / D converts a current transformed by the current transformer into a digital value. A current conversion circuit; a first voltage phase conversion unit that converts the phase of the output of the voltage conversion circuit by a first angle; and a second voltage phase conversion that converts the phase of the output of the voltage conversion circuit by a second angle. parts and, the current and the current phase converter for phase conversion by the first angle output of the conversion circuit, multiplies the output of the first voltage phase converter section and the current phase conversion unit before the correction active power ( x) an active power calculation unit for determining, and a reactive power calculation unit for multiplying the outputs of the second voltage phase conversion unit and the current phase conversion unit to determine the reactive power (y) before correction including the reactive power component. When, the pre-correction active power (x) and invalid containing power y) enter the phase shift of the phase difference of a voltage to the transformer and the voltage with respect to current at the primary side of the current transformer of the phase difference and the A / D converted current (phi), the transformer and Using the reciprocal number (A) of the current and voltage on the primary side of the current transformer and the ratio (amplitude deviation) of the current and voltage amplitude after A / D conversion , correction is performed by the amplitude / phase corrector shown in Equation 1. Amplitude / phase correction unit that outputs active power (x ') and reactive power (y') after correction, and an electric energy metering unit that integrates the output of this amplitude / phase correction unit and measures the electric energy And an electric energy indicator that displays the electric energy measured by the electric energy metering unit, so that the measurement accuracy of the electric energy is high and the phase and amplitude of the voltage converter and the current converter are wide. Yes.

  The amplitude / phase correction unit corrects the amplitude and phase of the active power based on the amplitude shift, phase shift, active power output from the active power calculation unit, and reactive power output from the reactive power calculation unit. Therefore, the calculation efficiency is good.

The amplitude / phase correction unit is configured to input a voltage of a known amplitude and phase and a current of a known amplitude and phase from the adjustment power source to the transformer and current transformer based on the input of the adjustment power source. The active power and reactive power before correction obtained by the active power calculator and reactive power calculator are obtained, and the active power and reactive power before correction , the known voltage, the known current, and the second A correction coefficient for phase shift and amplitude shift is obtained based on the theoretical effective power and reactive power obtained by the angle of the A / D conversion, so that the output from the transformer and current transformer is A / D converted. Multiplexer type can be used, and correction coefficient for phase deviation and amplitude deviation can be obtained even with only one type of known amplitude and phase voltage and known amplitude and phase current. It is possible.

  The amplitude / phase correction unit stores the output value output from one current conversion circuit when the adjustment current of the same current is input to each phase by the adjustment power supply, and other current conversion circuit The adjustment voltage of the same voltage is input to each phase by the reference current storage unit that stores the coefficient obtained by dividing the output value output from the output value output from the one current conversion circuit and the adjustment power supply. The output value output from one voltage conversion circuit and the coefficient obtained by dividing the output value output from the other voltage conversion circuit by the output value output from the one voltage conversion circuit. When measuring the reference voltage storage unit and the electric energy, the output of the other current conversion circuit is multiplied by the coefficient stored in the reference current storage unit, and the output of the other voltage conversion circuit is stored in the reference voltage storage unit. Multiply memorized coefficients Because a balance adjusting unit to balance the respective phase output, it is possible to balance at high speed, operation load of the small amplitude and phase correction of the metering.

  In addition, when the adjustment current storage unit that stores the adjustment current input from the adjustment power supply and the adjustment power supply input the same current for each phase by the adjustment power supply, the current is output from one current conversion circuit. A reference current storage unit that stores a coefficient obtained by dividing the output value output from another current conversion circuit by the output value output from the one current conversion circuit, and at the time of measuring the electric energy The output value output from the current conversion circuit for each phase, the adjustment current stored in the adjustment current storage unit, and the output output from one current conversion circuit stored in the reference current storage unit Since the current measuring unit that obtains the current of each phase based on the value and the coefficient of each phase is provided, the current can be accurately measured.

Further, since the fine adjustment of the coefficient after storing the coefficient is adjusted by the current downstream of the current measuring unit, the current can be accurately measured even after the fine adjustment.
In addition, when the adjustment voltage storage unit for storing the adjustment voltage input from the adjustment power supply and the adjustment voltage of the same voltage are input to each phase by the adjustment power supply, the voltage is output from one voltage conversion circuit. A reference voltage storage unit for storing a coefficient obtained by dividing the output value output from another voltage conversion circuit by the output value output from the one voltage conversion circuit, and when measuring the electric energy The output value output from the voltage conversion circuit for each phase, the adjustment voltage stored in the adjustment voltage storage unit, and the output output from one voltage conversion circuit stored in the reference voltage storage unit And a voltage measuring unit that obtains the voltage of each phase based on the value and the coefficient of each phase.

  The energy metering unit calculates the energy by integrating the output from the amplitude / phase correction unit over time, and outputs a pulse each time the energy reaches the threshold value. Rated memory unit that stores voltage, phase wire type, meter constant that determines the number of pulses to be output for the measured electric energy, and sampling frequency of A / D conversion, and rated current input from the rated memory unit Calculate the theoretical period of the pulse generated by the power meter when the rated power is input from the rated voltage, phase wire type, and meter constant, and from the amplitude / phase correction unit when the rated power is input. A full adjustment value calculation unit that detects the number of output bits per sampling and sets a value obtained by multiplying the number of bits by the sampling frequency input from the rated storage unit and the theoretical period as a threshold value; Tano , Voltage can be accurately measured.

In addition, since the power supply for adjustment outputs power having a rated voltage, a rated current, and a power factor of 1.0, the efficiency of adjusting the phase shift and the amplitude shift is good.
In addition, since the difference between the first angle and the second angle is 90 degrees and the reactive power is reactive power, the calculation efficiency is good.

A voltage conversion circuit for A / D converting the voltage transformed by the transformer into a digital value, a current conversion circuit for A / D converting the current transformed by the current transformer into a digital value, and the voltage conversion circuit A voltage phase conversion unit that phase-converts the output of the current conversion circuit by a first angle, a first current phase conversion unit that performs phase conversion of the output of the current conversion circuit by the first angle, and an output of the current conversion circuit A second current phase converter that performs phase conversion by an angle of 2, an active power calculator that multiplies the outputs of the voltage phase converter and the first current phase converter to obtain active power (x) before correction ; , The reactive power calculation unit for multiplying the outputs of the voltage phase conversion unit and the second current phase conversion unit to obtain the reactive power (y) before correction including the reactive power component, and the active power before correction ( x) and reactive power (y) are input, and the above transformer And a phase shift (φ) between the phase difference of the voltage with respect to the current on the primary side of the current transformer and the phase difference of the voltage with respect to the current after A / D conversion, on the primary side of the transformer and the current transformer Using the reciprocal number (A) of the current and voltage and the amplitude ratio (amplitude shift) of the current and voltage after A / D conversion, the corrected active power (x ') And the amplitude / phase correction unit that outputs reactive power (y'), the output of this amplitude / phase correction unit is integrated, the energy metering unit that measures the energy, and the above energy metering unit. Since the power amount display device for displaying the amount of electric power is provided, the power amount measurement accuracy is high, and it is possible to deal with a wide range of phase and amplitude shifts of the voltage converter and the current converter.

  Further, an error adjustment method for an electronic watt-hour meter according to the present invention includes a voltage conversion circuit for A / D converting a voltage transformed by a transformer into a digital value, and a current converted by the current transformer as a digital value. A current conversion circuit that performs A / D conversion, an active power calculation unit that integrates outputs of the voltage phase conversion unit and the current phase conversion unit to obtain active power, and an output of the voltage phase conversion unit is delayed by 90 degrees A reactive power calculation unit that calculates the reactive power by integrating the output and the output of the current phase conversion unit, and an energy metering unit that outputs a pulse when the value obtained by integrating the output of the active power calculation unit exceeds a threshold value; An error adjustment method for an electronic watt-hour meter comprising a power amount indicator that displays the amount of power measured by the power amount metering unit, wherein an adjustment power source is connected to the electronic watt-hour meter. All the rated power and power factor 1.0 from the power supply for adjustment A factor that balances each phase voltage at the time of measurement by calculating the ratio of the rated power input step to input to the voltage output from one voltage converter circuit and the voltage output from the other voltage converter circuit, and the inverse of this ratio. And the ratio of the current output from the one current conversion circuit and the current output from the other current conversion circuit is calculated, and the balance is stored as a coefficient for balancing the currents of each phase during measurement by the reciprocal of this ratio. From the adjustment step, the active power and reactive power obtained from the active power calculation unit and the reactive power calculation unit, and the active power and reactive power output from the adjustment power source, the transformer and the current transformer Phase adjustment conversion step for obtaining and storing a phase shift between the phase difference of the voltage relative to the current on the primary side and the phase difference of the voltage relative to the current after A / D conversion , A rated current, a rated voltage, a phase wire type, an instrument constant that determines the number of pulses output for the amount of power measured by the power meter, and an input unit for inputting a sampling frequency of A / D conversion; Since the power amount calculation unit includes a full adjustment value calculation step for setting a threshold value, the error adjustment time is short.

  A voltage conversion circuit for A / D converting the voltage transformed by the transformer into a digital value; a current conversion circuit for A / D converting the current transformed by the current transformer into a digital value; An active power calculation unit that integrates outputs of the voltage phase conversion unit and the current phase conversion unit to obtain active power, an output obtained by delaying the output of the voltage phase conversion unit by 90 degrees, and an output of the current phase conversion unit. A reactive power calculation unit for obtaining reactive power, an energy measuring unit that outputs a pulse when a value obtained by integrating outputs of the active power calculation unit exceeds a threshold value, and an electric energy measured by the energy measuring unit An error adjustment method for a multi-phase electronic watt-hour meter equipped with a watt-hour indicator for displaying an electric power meter, wherein a power supply for adjustment is connected to the electronic watt-hour meter with a single-phase two-wire connection between each phase. , Rated power to input the rated power and a predetermined power factor from the power supply for adjustment Based on the input step and the output of the power calculation unit and the reactive power calculation unit, a coefficient that is adjusted by rotation matrix calculation so that the power and reactive power of the other phase matches the power and reactive power of the one phase. Amplitude / phase adjustment step for obtaining the power amount output from the master meter in which the pulse output of the power amount connected to each of the adjustment power sources by single-phase two-wire connection is accurately adjusted, and the electronic A rated load adjustment step serving as a reference for the electric energy pulse output of the electronic electric energy meter, the amplitude / phase adjustment step, and the rated load adjustment step so that the output of the electric energy from the electric energy meter matches. After the adjustment, it includes a phase fine adjustment step for finely adjusting the phase of the electronic watt-hour meter based on the input from the adjustment power supply, so that error adjustment can be performed in the same manner as a single-phase two-wire instrument. Adjustment is facilitated.

  And a voltage conversion circuit for A / D converting the voltage transformed by the transformer into a digital value, a current conversion circuit for A / D converting the current transformed by the current transformer into a digital value, and the voltage phase conversion. Active power calculation unit that integrates the outputs of the current phase conversion unit and the current phase conversion unit to obtain active power, the output obtained by delaying the output of the voltage phase conversion unit by 90 degrees, and the output of the current phase conversion unit to integrate the reactive power Displays the required reactive power calculation unit, the energy measuring unit that outputs a pulse when the value obtained by integrating the outputs of the active power calculation unit exceeds a threshold, and the amount of power measured by the power measurement unit An error adjustment method for a multi-phase electronic watt-hour meter equipped with a watt-hour indicator, wherein the master meter is equivalent to the electronic watt-hour meter, the voltage conversion circuit, the current conversion circuit, and the active power calculation. Unit, reactive power calculation unit, and energy metering When a predetermined power is applied, power and reactive power are input from the power calculation unit and reactive power calculation unit of the electronic watt-hour meter, while the master meter The power and reactive power at that time are input from the power calculation unit and reactive power calculation unit, and the electronic power so that the power and reactive power of the electronic watt-hour meter match the power and reactive power of the master meter. Since the coefficient of the amplitude phase of the quantity meter is adjusted, it can be adjusted accurately and at high speed.

A voltage input unit that inputs a digitally converted voltage; a current input unit that inputs a digitally converted current; and a first voltage phase conversion unit that phase-converts the output of the voltage input unit by a first angle. A second voltage phase converter that converts the output of the voltage converter by a second angle, a current phase converter that converts the phase of the output of the current converter by the first angle, and the first the effective power calculating unit for obtaining a first voltage phase converter and said current multiplied by the output of the phase converter before correction active power (x), the output of the second voltage phase converter and said current phase converter Reactive power calculation unit that calculates the reactive power (y) before the correction including the reactive power component by multiplication, and inputs the active power (x) and the reactive power (y) before the correction , and inputs the transformer and the power Voltage against current on the primary side of the current transformer And the phase shift (φ) between the phase difference of the voltage and the voltage phase difference with respect to the current after A / D conversion, and the current and voltage on the primary side of the transformer and the current transformer, and the current after A / D conversion and Using the reciprocal number (A) of the voltage amplitude ratio (amplitude deviation), the corrected active power (x ') and reactive power (y') are output after correction by the amplitude / phase corrector shown in Equation 1. The power / accuracy measurement accuracy is high, and it is possible to deal with a wide range of phase and amplitude shifts of the voltage converter and the current converter.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below. FIG. 1 is a block diagram of an electronic watt-hour meter according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing the amplitude / phase corrector of FIG. 3 and 4 are diagrams showing a modification of the amplitude / phase corrector of FIG. FIG. 5 is a diagram for explaining the concept of amplitude / phase correction of FIG. 1, in which the horizontal axis is the active power axis, the vertical axis is the reactive power axis, and the clockwise direction is the direction in which the current advances with respect to the voltage. It is.

  In FIG. 1, 100 is an electronic watt-hour meter, 102 is a power calculation circuit, 110 is an A / D converter (voltage conversion circuit) for A / D converting voltage V from a transformer (not shown), and 112 is not shown. An A / D converter (current conversion circuit) for A / D converting the current I from the current transformer, and the A / D converters 110 and 112 are general-purpose ones that do not have a phase adjustment function by a shift register. Can be used.

  120 is a Hilbert transformer in-phase A (first voltage phase converter) that transforms the voltage into the same phase (first angle), and 122 is a Hilbert transform so that the voltage is orthogonal to the in-phase (second angle). Hilbert transformer quadrature (second voltage phase converter), 124 is a Hilbert transformer in-phase B (current phase converter) for Hilbert transforming the current into the same phase. Here, the Hilbert transform is well-known as a transform that delays the phase by 90 degrees, and these digital all-pass filters are described in “Digital filter design” (Miki Shikibu, published by Tokai University Press). is there.

126 is a multiplier (active power calculator) that multiplies the outputs of the Hilbert transform in-phase A 120 and the Hilbert transform in-phase B 124 and outputs the pre-correction active power x, and 128 is the output of the Hilbert transform quadrature phase 122 and the Hilbert transform in-phase B 124. Is a multiplier (reactive power calculation unit) that outputs reactive power y before correction.
Reference numeral 130 denotes an amplitude / phase corrector for correcting the active power x and the reactive power y, which will be described in detail later.

  Reference numeral 132 denotes an external correction unit that externally inputs a phase coefficient (also referred to as an external phase correction value) φ that is corrected so as to eliminate the phase shift and an amplitude coefficient (also referred to as an amplitude external correction value) A that is corrected so as to eliminate the amplitude shift. In the first embodiment, the phase coefficient φ and the amplitude coefficient A are known in advance. Here, the phase shift is caused by the phase and amplitude characteristics of a transformer or current transformer (not shown). The phase difference θ between the voltage and current on the primary side of the transformer or current transformer and the transformer or current transformer. The phase difference between the voltage and current phase difference (θ + φ) on the secondary side of the device. The amplitude coefficient is the reciprocal of the ratio (amplitude deviation) of the secondary side amplitude of the transformer or current transformer to the primary side amplitude of the transformer or current transformer. In the first embodiment, it is known that the phase of the current is shifted in the φ delay direction with respect to the voltage, and the amplitude is 1 / A times.

  134 is a power meter for integrating the corrected active power x ′ and the corrected reactive power y ′ to determine the amount of power, and 136 is the amount of active power and / or reactive power input from the power meter 134 to their magnitudes. A power amount pulse output unit 138 that outputs a corresponding number of pulses is a power amount display unit (power amount display unit) 138 that displays the active power amount and / or reactive power amount input from the power meter 134.

In FIG. 2, reference numeral 140 corrects the pre-correction active power x and the pre-correction reactive power y based on the phase external correction value φ and the amplitude external correction value A input from the external correction unit 132, and the post-correction active power x ′ and This is a two-dimensional amplitude / phase corrector that outputs reactive power y ′ after correction.
Next, the amplitude and phase correction operation when measuring the electric energy will be described.

Referring to FIG. 5, in order to correct the phase shift by the phase external correction value φ and the amplitude external correction value A input from the external correction unit 132, the effective power x before correction and the reactive power y before correction are rotated clockwise by φ. And the amplitude may be multiplied by A. That is, when the two-dimensional amplitude / phase corrector 140 (FIG. 2) receives the pre-correction active power x and the pre-correction reactive power y from the multiplier 126 and the multiplier 128, the phase input from the external correction unit 132 in advance. Using the external correction value φ and the amplitude external correction value A, the corrected active power x ′ and the corrected reactive power y ′ can be obtained by Equation 1.

  2 is replaced with low-pass filters 142, 144, 146, 148 before or after the two-dimensional amplitude / phase corrector 140, as shown in FIG. 3 or FIG. You may comprise so that it may provide. Since the low-pass filters 142, 144, 146, and 148 are provided, the harmonic component can be removed, and a pulse corresponding to the amount of power output from the power meter 134 of the electronic watt-hour meter 100 within one cycle of the power source. The error caused by jitter can be suppressed by calculating the measurement error by.

Since it is configured as described above, the phase external correction value φ is infinitely accurate and the measurement accuracy of the electric energy is high.
Further, the phase shift is not corrected by shifting the time by a shift register, but the outputs of the multipliers 126 and 128 that calculate the active power (active power x before correction x) and the reactive power (reactive power y before correction) are calculated. Since the correction is performed by two-dimensional conversion as shown in Equation 1 and FIG. 5, general-purpose products can be used as the A / D converters 110 and 112, and adjustment (correction) of accuracy and phase is possible. As the range is widened, there is no problem that the number of shift register stages increases and the area occupied by the chip (substrate) increases, and not only the setting and adjustment of the number of shift register stages for phase shift is not necessary, but also the phase and / or It can also be used for current transformers and transformers with large amplitude deviations and variations, and when shifting time using a shift register As the phase becomes larger, the error becomes larger and the correction time becomes longer. On the other hand, even if a current transformer or transformer with a large phase and / or amplitude deviation is used, the power metering accuracy uses a shift register. The correction is higher than in the case of time shifting, and the correction can be performed in a short time.

In addition, the Hilbert transformer in-phase A120, the Hilbert transformer quadrature 122, and the Hilbert transformer in-phase B124 make the Hilbert transform in which the difference between the first angle and the second angle is 90 degrees, so that the calculation speed is fast and effective. Power and reactive power can be obtained simultaneously.
In the above-described correction, the external phase correction value φ and the external amplitude correction value A are separately given. However, if Acos φ and Asin φ are given as external correction values, the amplitude and phase can be corrected simultaneously, and the calculation efficiency is good.
Moreover, although the example which carries out 90 degree phase conversion of a voltage by the Hilbert transform quadrature phase 122 was demonstrated, you may carry out 90 degree phase conversion of an electric current.

Embodiment 2. FIG.
The second embodiment of the present invention will be described below. FIG. 6 is a block diagram of an electronic watt-hour meter according to Embodiment 2 of the present invention. FIG. 7 is a flowchart for explaining the operation of the self-corrector of FIG. FIG. 8 is a diagram for explaining the concept of the amplitude / phase correction of FIG. 6, wherein the horizontal axis is the active power axis, the vertical axis is the reactive power axis, and the clockwise direction is the direction in which the current advances with respect to the voltage. It is.

  In FIG. 6, 150 is a self-corrector that holds parameters such as a phase coefficient and an amplitude coefficient, 152 is a true value storage unit, and includes a transformer (not shown) by an imaginary load power supply (adjustment power supply) not shown. A voltage V and current I having a known amplitude and phase to be injected into the primary side of the current transformer are stored. Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

Next, the operation will be described.
A voltage V and current I of known amplitude and phase are injected into the primary side of a transformer and a current transformer (not shown) by an imaginary load power source for adjustment (not shown). The pre-correction active power x and the pre-correction reactive power y, which are the outputs of the multipliers 126 and 128 obtained from the voltage V and current I, are distorted in amplitude and phase by a transformer, current transformer, analog circuit, etc. (not shown). It is out.

On the other hand, the voltage V and current I of known amplitude and phase injected by the imaginary load power supply for adjustment are stored in the true value storage unit 152 by manual input or communication with the imaginary load power supply for adjustment.
In the adjustment mode with the imaginary load power source for adjustment, the electronic watt-hour meter 100 self-corrects the pre-correction active power x ″ and the pre-correction reactive power y ″ by the path 150a that is not corrected by the amplitude / phase corrector 130. This is given to the corrector 150.

Referring to FIG. 7, self-corrector 150 receives voltage V and current I of known amplitude and phase from true value storage unit 152 (S10), and from these, active power true value (theoretical value) X and invalidity are input. The electric power true value (theoretical value) Y is calculated (S12).
Next, the pre-correction active power x ″ and the pre-correction reactive power y ″ are input from the path 150a (S14), and the active power true value X, the reactive power true value Y, the pre-correction active power x ″, and the pre-correction invalid power. The power y ″ calculates α and β, which will be described later, including the correction angle (phase coefficient) ψ and the amplitude correction value (amplitude coefficient) B as follows, and self-correction values α and β are self-corrected by the path 150b. The value is output to the amplitude / phase corrector 130 (S16).

The calculation in S16 will be described with reference to FIG.
The relationship among the true active power true value X, the reactive power true value Y, the pre-correction active power x ″, the pre-correction reactive power y ″, the correction angle ψ, and the amplitude correction value B is expressed by Equation 2.

と表される。式３からαとβを求めると、 Here, in Equation 2, if B cos ψ = α and B sin ψ = β,

It is expressed. When α and β are obtained from Equation 3,

となる。αとβは振幅補正値Ｂと補正角ψの両方を含んでいるため、そのまま補正値として使用することができる。

It becomes. Since α and β include both the amplitude correction value B and the correction angle ψ, they can be used as correction values as they are.

When the self-corrector 150 wants to know the amplitude correction value B and the correction angle ψ, it can be obtained by Equation 5.

When the amplitude / phase corrector 130 stores the self-correction values α and β after S16, the electronic watt-hour meter 100 ends the adjustment mode and enters the normal measurement mode.
In the measurement mode, when voltage V and current I are input from a transformer or current transformer (not shown), the corrected effective power x ′, The corrected reactive power y ′ can be obtained.

  Since the A / D converters 110 and 112 that take in the voltage V and the current I are not simultaneously sampled, the A / D converter can be corrected including the sampling deviation. A single multiplex A / D converter may be used instead of the D converters 110 and 112.

In addition, since the input voltage is phase-shifted by 90 degrees and the pre-correction active power and the pre-correction reactive power are calculated, a plurality of types of amplitude / phase such as power factor 1.0 and power factor 0.5 as in the past The imaginary load power supply for adjustment can obtain the self-correction values α and β by inputting only one type of voltage V and current I having a known amplitude and phase. Easy and quick.
Further, since the pre-correction active power x and the pre-correction reactive power y are corrected by the self-correction values α and β, the calculation efficiency is good.

  Although an example in which the pre-correction active power x and the pre-correction reactive power y are corrected using the self-correction values α and β has been described, the pre-correction active power is corrected using the amplitude correction value B and the correction angle ψ as in the first embodiment. x and reactive power y before correction may be corrected.

Embodiment 3 FIG.
Hereinafter, the third embodiment will be described. FIG. 9 is a block diagram of an electronic watt-hour meter according to Embodiment 3 of the present invention. The third embodiment is a combination of the first embodiment and the second embodiment. In the correction, the self-corrector 150 first calculates a correction value as described in the second embodiment, and further performs fine adjustment using the external correction value.

The active power before correction is x, the reactive power y before correction, the amplitude correction value obtained by the self-corrector 150 is B (times), the correction angle is ψ, the external correction value of amplitude is A (times), and the external correction value of angle Is φ, active power x ′ after correction, and reactive power y ′ after correction, correction at the time of weighing is performed by Equation 7.

とできる。ここで、

である。
以上のように構成したので、自己補正と外部補正を同時に行うことができ効率がよい。 At this time, if the correction coefficient portion is calculated in advance to simplify the calculation in Equation 7,

And can. here,

It is.
Since it comprised as mentioned above, self-correction and external correction can be performed simultaneously, and it is efficient.

Embodiment 4 FIG.
Embodiment 4 of the present invention will be described below. FIG. 10 is a block diagram of a three-phase four-wire electronic watt-hour meter according to Embodiment 4 of the present invention. FIG. 11 is a diagram showing an adjustment flow of the electronic watt-hour meter of FIG. FIG. 12 is a diagram showing a flow of balance adjustment in the electronic watt-hour meter of FIG. FIG. 13 is a diagram showing a flow of phase adjustment in the electronic watt-hour meter of FIG. FIG. 14 is a diagram showing a flow of full adjustment in the electronic watt-hour meter of FIG. FIG. 15 is a vector diagram showing the relationship between active power and reactive power during phase adjustment in the electronic watt-hour meter of FIG. FIG. 16 is a vector diagram showing the relationship between active power and reactive power during power metering in the electronic watt-hour meter of FIG. FIG. 17 is a diagram showing the relationship between the threshold value and the electric energy pulse in the electronic watt-hour meter of FIG. FIG. 18 is a flowchart for explaining current measurement in the electronic watt-hour meter of FIG.

In FIG. 10, 200 is an electronic energy meter, 221 is a current transformer, 222 is a transformer, 223 is a current conversion circuit for A / D converting the input current into a digital value proportional to the input current, and 224 is the input voltage. Is a voltage conversion circuit that performs A / D conversion into a digital value proportional to the input voltage, 225 is an effective value current calculation unit that calculates an effective value of each phase current from the output of the current conversion circuit 223, and 226 is an output of the voltage conversion circuit 224 Is an effective value voltage calculation unit for obtaining the effective value of the voltage of each phase from
231 is a current balance adjustment multiplier that multiplies the current balance adjustment value by the output of the current conversion circuit 223, 232 is a voltage balance adjustment multiplier that multiplies the voltage balance adjustment value by the output of the voltage conversion circuit 224, and 234 is the B phase with respect to the A phase voltage. It is a balance adjustment value calculation part (balance adjustment part) which calculates | requires the balance adjustment value of the voltage, the balance adjustment value of C phase voltage, the B phase current with respect to A phase current, and the C phase current.

Reference numeral 241 multiplies the output proportional to the current of each phase of the current conversion circuit 223 by the output proportional to the voltage of each phase of the voltage conversion circuit 224, and the phase adjustment that is the output of the phase adjustment value calculation unit 244 It is an active power multiplier (active power calculator) that multiplies values to obtain active power.
Reference numeral 242 denotes a Hilbert converter that inputs an output proportional to the current of each phase of the current conversion circuit 223 and delays the current phase of each phase by 90 degrees. In the fourth embodiment, only the Hilbert transformer 242 is shown as a configuration equivalent to the Hilbert transform in-phase and the Hilbert transform quadrature described in the first to third embodiments for simplification of description. That is, in FIG. 10, instead of the Hilbert transformer 242, the Hilbert explained in the first embodiment immediately before the active power multiplier 241 on the output side of the Hilbert quadrature and current converter circuit 233 explained in the first embodiment. In-phase, the one in which the Hilbert in-phase described in Embodiment 1 is provided immediately after the output side of the voltage conversion circuit 224 is equivalent.

  243 is an output of the Hilbert converter 242 which is multiplied by an output proportional to the 90-degree delayed current of each phase and an output proportional to the voltage of each phase, and the calculation result is the phase which is the output of the phase adjustment value calculation unit 244 It is a reactive power multiplier that obtains reactive power by multiplying an adjustment value. Reference numeral 244 denotes a phase adjustment value calculation unit for obtaining a phase adjustment value for adjusting the phase shift of the current of each phase with respect to the voltage of each phase, and 245 denotes a digital low-pass filter that passes only the DC component of the output of each phase of the active power multiplier 241. 246 is a digital low-pass filter that passes only the DC component of the output of each phase of the reactive power multiplier 243, 247 is an adder that adds the outputs of each phase of the digital low-pass filter 245, and 248 is each phase of the digital low-pass filter 246 Is an adder. The output of the current conversion circuit 223 corresponds to the first current phase conversion unit, the Hilbert converter 242 corresponds to the second current phase conversion unit, and the output of the voltage conversion circuit 224 corresponds to the voltage phase conversion unit.

  Reference numeral 251 denotes an active energy / frequency converter that outputs a pulse when the active energy obtained by integrating the outputs of the adder 247 becomes larger than the threshold value output by the full adjustment value calculation unit 253, and 252 indicates the output of the adder 248. The reactive power amount / frequency converter 253 outputs a pulse when the reactive power amount obtained by integrating the values becomes larger than the threshold value output from the full adjustment value calculation unit 253. The active power amount / frequency converter 251 and the reactive power amount 253 A full adjustment value calculation unit 254 for obtaining a threshold value of the frequency converter 252 is an oscillation circuit that oscillates at the same cycle as the sampling frequency of the current conversion circuit 223 and the voltage conversion circuit 224.

  Reference numeral 255 denotes a calculation control unit that controls the balance adjustment value calculation unit 234, the phase adjustment value calculation unit 244, and the full adjustment value calculation unit 253. Reference numeral 261 denotes an active power amount / frequency converter 251 and a reactive power amount / frequency converter 252. A counter 271 measures the pulse. The measured value of the active power and the reactive power measured by the counter 261, the effective value current of each phase measured by the effective value current calculating unit 225, and the measured value of the effective value voltage calculating unit 226. A display for displaying the effective value voltage of the phase, 272 is an adjustment switch, 273 is an EEPROM, 274 is an arithmetic circuit for electric energy, and 281 is a virtual load power supply (adjustment power supply) used for adjustment. 290 is a V / I measuring unit (current measuring unit, voltage measuring unit) for measuring voltage and current, and 292 is a terminal for outputting the measured voltage and current.

Next, adjustment will be described.
The adjustment procedure for setting the measurement accuracy of the electronic watt-hour meter 200 within the allowable error range is as follows, as shown in the flowchart of FIG.
(1) Rated power, application of power factor (S100),
(2) Setting of rated value (rated setting) (S200),
(3) Adjustment (balance adjustment) of variation in amplitude and amplitude of voltage and current of each phase (S300),
(4) Adjustment of phase difference between voltage and current for each phase (phase adjustment) (S400),
(5) Adjustment of power amount / frequency conversion threshold when rated power is applied (full adjustment) (S500)

Hereinafter, S100 to S500 will be described in detail.
(1) Application of rated power and power factor (S100)
An imaginary load power source 281 for adjustment is connected to the electronic watt-hour meter 200 to be adjusted. The virtual load power supply 281 applies a rated power having a power factor of 1.0 to the electronic watt-hour meter 200.
(2) Rating setting (S200)
In the fourth embodiment, the description will be made assuming that the phase wire type is a three-phase four-wire type, the rated voltage is 240 V, the rated current is 5 A, and the meter constant is 10,000 pulses / kWh. The rated value is registered in the EEPROM (measurement storage unit) 273 in advance.

  Adjustment is started by pressing the adjustment switch 272. The rated value (phase wire type, rated voltage, rated current, meter constant) of the electronic watt-hour meter 200 stored in the EEPROM 273 is read and set in the arithmetic control unit 255. The phase to be adjusted is determined from the rated value set in the arithmetic control unit 255. That is, in the case of the three-phase four-wire system, the balance adjustment and phase adjustment are all of the A phase, the B phase, and the C phase. In the case of a single-phase three-wire system and a three-phase three-wire system, the phase is A and C. In the single-phase two-wire system, only the A phase is provided.

(3) Balance adjustment Balance adjustment will be described with reference to FIG.
The current balance adjustment includes a current transformer 221 and a current conversion circuit for the B phase current with respect to the A phase current and the C phase current with respect to the A phase current at the output of the current conversion circuit 223 when the same current is input to the A phase to the C phase. The variation based on the circuit constant of H.223 is corrected. In the voltage balance adjustment, when the same voltage is input to the A phase to the C phase, the transformer 222 between the B phase voltage for the A phase voltage and the C phase voltage for the A phase voltage in the voltage conversion circuit 224, and the voltage conversion circuit 224 The variation based on the circuit constant is corrected.

  When the adjustment switch 272 is pressed in S200 (FIG. 11), the electronic watt-hour meter 200 enters the adjustment mode, and the rated power with a power factor of 1.0 is applied to the primary side of the current transformer 221 and the transformer 222. And output from the secondary side to the current conversion circuit 223 and the voltage conversion circuit 224. The current conversion circuit 224 and the current conversion circuit 223 convert the input analog signal into a digital signal for each phase and output the digital signal.

The effective value current calculation unit (Irms) 225 calculates the A-phase effective value current, the B-phase effective value current, and the C-phase effective value current based on the output from the current conversion circuit 223 (S302, S304, S306).
Similarly, the effective value voltage calculation unit (Vrms) 226 calculates an A-phase effective value voltage, a B-phase effective value voltage, and a C-phase effective value voltage based on the output from the voltage conversion circuit 224 (S312, S314, S316). .

The balance adjustment value calculation unit 234 receives the A-phase effective value current, the B-phase effective value current, the C-phase effective value current from the effective value current calculation unit 225, and the A-phase effective value voltage and B-phase from the effective value voltage calculation unit 226. The effective value voltage and the C-phase effective value voltage are input (S318).
The balance adjustment value calculation unit 234 obtains the B-phase current balance adjustment value by the following calculation (S320).

“B-phase current balance adjustment value” = “B-phase RMS current” ÷ “A-phase RMS current”
By multiplying the B-phase current balance adjustment value by the multiplier 231 by the B-phase A / D conversion output of the current conversion circuit 223, the variation in the circuit constant of the B-phase current is corrected.
The C-phase current balance adjustment value is also obtained in the same manner (S322).
The balance adjustment value calculation unit 234 obtains a B-phase voltage balance adjustment value by the following calculation (S324).

"B phase voltage balance adjustment value" = "B phase effective value voltage" ÷ "A phase effective value voltage"
By multiplying the B-phase voltage balance adjustment value by the multiplier 232 to the B-phase A / D conversion output of the voltage conversion circuit 224, the variation in the circuit constant of the B-phase voltage is corrected.
The C-phase voltage balance adjustment value is also obtained in the same manner (S326).
Each balance adjustment value obtained in S320 to S326 is stored in the EEPROM 273 (S328). By S328, the control calculation unit 225 ends the balance adjustment and proceeds to the phase adjustment.

(4) Phase Adjustment Phase adjustment will be described with reference to FIG.
In the phase adjustment, when the same phase voltage and current are input to each phase of A phase to C phase, the A phase current for the A phase voltage and the B phase current for the B phase voltage at the outputs of the current conversion circuit 223 and the voltage conversion circuit 224 The phase difference of the C-phase current with respect to the C-phase voltage is corrected. This phase difference is generated by the current transformer 221, the transformer 222, the current conversion circuit 223, and the voltage conversion circuit 224.
The principle of phase adjustment will be described below.

FIG. 15 shows the effective power W ₀ which is the calculation result of each of the adder 247 and the adder 248 when the rated power and the power of 1.0 are applied to the electronic watt-hour meter 200 before the phase adjustment. is a vector diagram representing the relationship of the reactive power var _0. The power factor is 1.0 because the current transformer 221, the transformer 222, the current conversion circuit 223, and the voltage conversion circuit 224 generate a phase difference (phase shift) between the current and the voltage, but it is invalid. Electric power is generated.

If W ₀ and var ₀ are taken on the coordinates, and X ₀ (W ₀ , var ₀ ), when the rated power and power factor of 1.0 are input, the angle to be corrected is φ, and the angle φ is , Φ = arctan (var ₀ ÷ W ₀ ).
FIG. 16 is a vector diagram showing the relationship between active power and reactive power, which are the calculation results of the adder 247 and the adder 248 of the electronic watt-hour meter 200 during power metering. The phase difference between the active power W ₁ and reactive power var ₁ before phase adjustment and the active power W ₂ and reactive power var ₂ after phase adjustment is the angle φ.

したがって、
Ｗ_２＝Ｗ_１ｃｏｓφ+ｖａｒ_１ｓｉｎφおよび
ｖａｒ_２＝−Ｗ_１ｓｉｎφ+ｖａｒ_２ｃｏｓφ
を計算することで、位相差が調整される。 During the measurement, the coordinate X ₂ (W ₂ , var ₂ ) after phase adjustment is obtained by Equation 10 from the coordinate X ₁ (W ₁ , var ₁ ) before phase adjustment and the angle φ obtained by the phase adjustment.

Therefore,
W ₂ = W ₁ cos φ + var ₁ sin φ and var ₂ = −W ₁ sin φ + var ₂ cos φ
Is calculated to adjust the phase difference.

The phase adjustment is performed according to the following procedure based on FIG.
The output of the active power multiplier 241 is input to the digital low-pass filter 245, and the A-phase active power, the B-phase active power, and the C-phase active power are output from the digital low-pass filter 245.
The output of the reactive power multiplier 243 is input to the digital low pass filter 246, and the A phase reactive power, the B phase reactive power, and the C phase reactive power are output from the digital low pass filter 246.

The phase adjustment value calculation unit 244 inputs the A phase active power, the B phase active power, the C phase active power, the A phase reactive power, the B phase reactive power, and the C phase reactive power from the digital low-pass filters 245 and 246 (S402). To S416)
The phase adjustment value calculation unit 44 obtains the A phase adjustment value by the following calculation using the A phase active power and the A phase reactive power (S422).

“A phase adjustment value” = arctan (“A phase active power” ÷ “A phase reactive power”)
Similarly, B-phase and C-phase phase adjustment values are obtained (S424, S426). In this case, only “A phase active power” and “A phase reactive power” are changed to “B phase active power” and “B phase reactive power”, or “C phase active power” and “C phase reactive power”. It calculates | requires by the method similar to the said A phase.
The phase adjustment value obtained in S422 to S426 is stored in the EEPROM 273 (S430). By S430, the control calculation unit 225 completes the phase adjustment and proceeds to full adjustment.

(5) Full Adjustment Full adjustment will be described with reference to FIG.
The calculation result of the active power that is the output of the adder 247 is input to the active power amount / frequency converter 251. The active energy / frequency converter 251 time-integrates the input value (active power) and inputs the value from the oscillation circuit 254 when the integration result exceeds the threshold set by the full adjustment value calculation unit 253. By outputting a pulse, a pulse proportional to the amount of active power is output to the counter 61 (see FIG. 17).

  Similarly, the reactive power amount / frequency converter 252 time-integrates the input reactive power calculation result, and when the integration result exceeds the threshold set by the full adjustment value calculation unit 253, the oscillation circuit 254 Is output to the counter 61 (see FIG. 17).

  For example, when the sampling frequency of the A / D converter used for the current conversion circuit 223 and the voltage conversion circuit 224 is 2 kHz, the data from the current conversion circuit 223 and the voltage conversion circuit 224 are updated once every 0.5 ms. Therefore, the calculation (threshold value check) of the electric energy by the active electric energy / frequency converter 251 and the reactive electric energy / frequency converter 252 is performed once every 0.5 ms. Accordingly, the active power amount pulse of the active power amount / frequency converter 251 and the reactive power amount pulse of the reactive power amount / frequency converter 252 have a maximum frequency of 2 kHz, and the oscillation circuit 254 outputs the pulse of 2 kHz to the active power amount / frequency converter. 251 and the reactive energy / frequency converter 252 need to be output.

In full adjustment, when the rated power and power factor of 1.0 are input from the imaginary load power supply 281, the frequency of the active energy pulse output from the active energy / frequency converter 251 is determined by the meter constant and the rated power. Similarly, the reactive power amount / frequency converter 252 determines and uses a threshold value at which the frequency of the reactive power pulse becomes a frequency determined by the meter constant and the rated power.
The frequency (active power rated pulse frequency) of the active power amount pulse output from the active power amount / frequency converter 251 and the reactive power amount / frequency converter 252 from the rated value set in the arithmetic control unit 255 when the rated power is input. The frequency (reactive power rated pulse frequency) of the reactive power amount pulse output from is obtained (S502).

In the fourth embodiment, the frequency of the active power amount pulse when the rated power and power factor of 1.0 are input (active power rated pulse frequency) is 3 × 240 V × 5 A = 3.6 kWh, and the instrument constant is 10000 pulses. Since it is / kWh, 10000 × 3.6 ÷ 3600 = 10 Hz. Similarly, the frequency of the reactive power amount pulse when the rated power and the power factor of 0.0 are input (reactive power rated pulse frequency) is the rated power of 3 × 240 V × 5 A = 3.6 kvarh, and the instrument constant is 10,000 pulses / kvarh. Therefore, 10000 × 3.6 ÷ 3600 = 10 Hz. Accordingly, when the rated power is input for both the active power amount pulse and the reactive power amount pulse (active power amount is power factor 1.0, reactive power amount is power factor 0.0), one pulse is output every 100 ms.
The threshold value of the active energy pulse is obtained by the following method (S504). The active energy / frequency converter 251 time-integrates the calculation result input from the adder 247. For example, assuming that the output (number of bits) from the adder 247 per sampling when a rated power with a power factor of 1.0 is input is constant at 0708h (h: hexadecimal number), since 100 ms is accumulated for 200 times, The accumulated value (number of bits) is 57E40h. Therefore, 57E40h becomes a threshold value, and a pulse input from the oscillation circuit 254 is output to the counter 261 every time the time integration result in the active energy / frequency converter 251 exceeds 57E40h.

  The threshold value of the reactive energy pulse is obtained by the following method (S506). During the adjustment, the rated power and the power factor of 1.0 are input to the electronic watt-hour meter 200 to be adjusted, so the reactive power is zero. However, since the outputs from the current conversion circuit 223 and the voltage conversion circuit 224 are balanced and phase-adjusted, the reactive power calculation result of the adder 248 when the rated power and the power factor of 0.0 are input is the adder 247. It becomes the same value as the active power calculation result of 0708h per sampling. Therefore, the threshold value of the reactive energy is 57E40h which is the same value as the threshold value of the active energy, and the pulse input from the oscillation circuit 255 every time the result of time integration in the reactive energy / frequency converter 52 exceeds 57E40h. Is output to the counter 261.

  The threshold value (adjustment value) obtained in S502 to S506 is stored in the EEPROM 273 (S508). In S508, the full adjustment is finished, and the adjustment for keeping the measurement accuracy of the electronic watt-hour meter 200 within the allowable error range is finished.

Next, current and current measurement will be described.
Referring to FIG. 18, in S200 (FIG. 11) described above, the rated current set in operation control unit 255 is input to VI measurement unit 290 and stored (S610).
Next, at the time of balance adjustment, the A phase effective value current in S302 (FIG. 12) is inputted and stored (S612).

Next, the A-phase rated current obtained in S610 and S612 is made to correspond to the magnitude of the A-phase effective value current (S614). For example, if the rated current is 5A and the effective value is 0960h, the value is associated with 5A when 0960h.
When the electronic energy meter 200 is in the energy metering mode, the output from the current conversion circuit 223 is input to the effective value current calculator 225. At this time, the current (output) as it is for the A phase is input to the effective value current calculation unit 225, and the current that is balance-adjusted by the balance adjustment multiplier 231 is input to the other B phase and C phase. The effective value current calculated by the effective value current calculating unit 225 is input to the V and I measuring unit 290.

The V / I measuring unit 290 that has received the RMS current measures the current based on the input current that is the RMS current, the rated current associated in S614, and the A-phase RMS current (S616). For example, if the input current is 0900h, the current = 0900h ÷ 0960h × 5A = 4.8A. This measured value is output from the terminal 292 or displayed on the display 271.
The voltage can also be measured in the same manner as described above.

As described above, the error adjustment method of the electronic watt-hour meter can adjust the balance adjustment, the phase adjustment, and the full adjustment only by inputting the rated power and the power factor of 1.0 from the imaginary load power supply 281. Adjustment time is automated and shortened, improving mass productivity.
Moreover, even if the meter constant, which is the pulse frequency when the rated power is input, is greatly changed, the adjustment can be performed in a short time.

In addition, a test power supply device that communicates with an electronic watt-hour meter as in the conventional example, and has a function of performing energization control and phase switching is unnecessary, and only the imaginary load power supply 281 is required. Can be configured.
In addition, the voltage and current of each phase are accurately measured in order to perform balance adjustment and phase adjustment for the voltage and current signals of the phase that causes variation, based on the measurement results of the voltage and current of each phase. be able to.

  Further, since the voltage is not shifted in time as in the prior art, that is, the shift register is not used, the same effect as in the first embodiment can be obtained. Further, a multiplexer-type A / D converter can be used for the current conversion circuit 223 and the voltage conversion circuit 224, and the input unit of the electronic watt-hour meter 200 can be downsized.

  Compared to the first embodiment, the balance can be adjusted at high speed, and the calculation load on the active power multiplier 241 and the reactive power calculation unit 243 (amplitude / phase correction unit) during measurement is small. In the calculation of S302 to S318 (FIG. 11) by the calculation unit 234, the example of adjusting the balance of current and voltage with reference to the A phase has been described. However, when the execution value of each phase is input in S318, the magnitude thereof However, the balance adjustment value in S320 to S328 may be obtained using the intermediate phase as a reference phase. In this case, it is necessary to provide the current balance adjustment calculation unit 231 and the voltage balance adjustment calculation unit 232 in the A phase. However, the phase shift is often reduced, the measurement accuracy is improved, and the phase adjustment calculation is performed. Time can be shortened.

Moreover, although the example which inputs rated power and a power factor 1.0 from the imaginary load power supply 281 was demonstrated, even if predetermined power and a predetermined power factor are input, although adjustment time is somewhat required, error adjustment can be performed.
In the above description, an example of adjusting with a power factor of 1.0 has been described. However, it is preferable to adjust with a power factor of 0.5 from the viewpoint of high-precision adjustment. That is, when adjusted with a power factor of 0.5, the rate of change in active power due to phase change is greater than when adjusted with a power factor of 1.0, and reactive power is greater than when adjusted with a power factor of 1.0. This is because the phase can be adjusted with higher accuracy.

Embodiment 5 FIG.
The fifth embodiment of the present invention will be described below. FIG. 19 is a block diagram of an electronic watt-hour meter according to Embodiment 5 of the present invention. In FIG. 19, 310 is a fine balance adjustment unit, 312 is a current balance fine adjustment unit provided downstream of the multiplier 243, and 314 is a voltage balance fine adjustment value calculation unit provided downstream of the multiplier 241. is there. Since other configurations are the same as those of the fourth embodiment, description thereof is omitted.

  The balance fine adjustment unit 310 is used only when fine adjustment with the master meter is necessary after performing error adjustment in S100 to S500 (FIG. 11), and its configuration is a balance adjustment value calculation. It is the same as that of the part 234, and the balance adjustment value of the B phase and the C phase is obtained according to the procedure of S302 to S328 (FIG. 12). The difference from the balance adjustment value calculation unit 234 is that the balance adjustment value is provided to the current balance fine adjustment calculation unit 312 and the voltage balance fine adjustment calculation unit 314 when measuring the electric energy. When fine adjustment of the balance is performed, fine adjustment of the phase and full fine adjustment are usually performed, but these are adjusted by the phase adjustment calculation unit 244 and the full adjustment calculation unit 253 as in the fourth embodiment.

  As described above, since the fine adjustment of the balance is adjusted on the downstream side of the multipliers 241 and 243 for calculating the power, the accuracy by the effective value current calculating unit 225 and the effective value voltage calculating unit 226 can be maintained, and V The current and voltage can be accurately measured by the I measuring unit 290 (shown only in FIG. 10) even after fine adjustment.

Embodiment 6 FIG.
The sixth embodiment of the present invention will be described below. FIG. 20 is a block diagram of an electronic watt-hour meter according to Embodiment 6 of the present invention. Although two phases are not shown, the configuration is the same as that of one phase and three phases.

  AD converters (voltage conversion circuits) 110_1 and 110_3 for AD conversion of voltage signals, and AD converters (current conversion circuits) 112_1 and 112_3 for AD conversion of current signals are provided, and outputs of the voltage conversion circuits 110_1 and 110_3 , Multipliers (active power calculators) 126_1 and 126_3 for multiplying the outputs of the current conversion circuits 112_1 and 112_3 and outputting the pre-correction active power x (x1, x3), and Hilbert so that the voltages are orthogonal to the in-phase Hilbert transformer quadrature (voltage phase converter) 122_1, 122_3 for conversion, Hilbert transformer in-phase (current phase converter) 124_1, 124_3 for converting current into the same phase, outputs of the voltage phase converters 122_1, 122_3 and the above Multiply by outputs of current phase converters 124_1 and 124_3, and disable before correction Comprising a force y (y1, y3) and outputs a multiplier (invalid containing power calculating section) 128_1,128_3. Also, amplitude phase correctors 130_1 and 130_3 are provided which input pre-correction active power x and pre-correction reactive power y, and output corrected active power x 'and post-correction active power y'.

In addition, by providing averaging processing (for example, a low-pass filter) 127_1, 127_3, 129_1, and 129_3 before the amplitude phase correctors 130_1 and 130_3, the pre-correction power x input to the amplitude phase correctors 130_1 and 130_3 and the pre-correction. Since the reactive power y is stable, accurate amplitude correction and phase correction are possible.
In addition, the coefficient α and the coefficient β (see Embodiment 2) in the amplitude phase correctors 130_1 and 130_3 can be set from the outside.

Further, the power meter 134 for integrating the corrected active power x ′ and the corrected reactive power y ′ to obtain the power amount, and the active power amount and / or the reactive power amount input from the power meter 134 are set to their magnitudes. An electric energy pulse output unit 136 for outputting a corresponding number of pulses is provided.
Further, the instantaneous value averaging units 190_1 and 190_3 for inputting and averaging the corrected effective power x ′, the power communication buffer units 191_1 and 191_3 for outputting the outputs of the instantaneous value averaging units 190_1 and 190_3 by communication, and the instantaneous Electric power physical quantity converters 192_1 and 192_3 for converting the outputs of the value averaging sections 191_1 and 191_3 into physical quantities, instantaneous value averaging sections 194_1 and 194_3 for inputting and averaging the corrected reactive power y ′, and instantaneous value averaging sections 194_1 , 194_3, and reactive power physical buffer converters 196_1 and 196_3 for converting the outputs of the instantaneous value averaging units 194_1 and 194_3 into physical quantities for each phase.

  The physical quantity conversion coefficients W1a, W3a, Var1a, and Var3a used for the power physical quantity conversion units 192_1 and 192_3 and the reactive power physical quantity conversion units 196_1 and 196_3 can be set from the external setting units 193_1, 193_3, 197_1, and 197_3. The physical quantity conversion coefficients W1a, W3a, Var1a, and Var3a used for the power physical quantity conversion units 192_1 and 192_3 and the reactive power physical quantity conversion units 196_1 and 196_3 have already been subjected to amplitude adjustment and phase adjustment by the amplitude phase correction unit. In this case, a common value may be used for each phase, thereby reducing the memory capacity and setting items.

In addition, the power physical quantity conversion units 192_1 and 192_3 and the reactive power physical quantity conversion units 196_1 and 196_3 do not always have to operate, and when the instantaneous power W (W1, W3) and the instantaneous reactive power Var (Var1, Var3) are requested. Since only the operation is required, the amount of calculation can be reduced.
The effective value voltage calculation units 170_1 and 170_3 for calculating the effective values of the outputs from the voltage conversion circuits 110_1 and 110_3, the effective value current calculation units 180_1 and 180_3 for calculating the effective values of the outputs from the current conversion circuits 112_1 and 112_3, and the above effective values. Instantaneous value averaging units 172_1 and 172_3 for averaging the outputs of the value voltage calculation units 170_1 and 170_3, the effective value voltage communication buffer units 174_1 and 174_3 for outputting the outputs of the instantaneous value averaging units 172_1 and 172_3 through communication, RMS value voltage physical quantity converters 178_1 and 178_3 that convert the outputs of the value averaging units 172_1 and 172_3 into physical quantities, instantaneous value averaging sections 182_1 and 182_3 that average the outputs of the RMS current calculators 180_1 and 180_3, and instantaneous values The outputs of the averaging units 182_1 and 182_3 are passed through. Rms current communication buffer unit 184_1,184_3 for outputting at comprises an effective value current physical quantity converter 188_1,188_3 for converting the output of the instantaneous value averaging unit 182_1,182_3 the physical quantity for each phase.

  The physical quantity conversion coefficients V1a, V3a, I1a, and I3a used for the RMS voltage physical quantity converters 178_1 and 178_3 and the RMS current physical quantity converters 188_1 and 188_3 are obtained from the external setting units 176_1, 176_3, 186_1, and 186_3. Can be set. Phase adjustment is not necessary in the calculation of the effective value, and amplitude adjustment in the calculation of the effective value is performed in the effective value voltage physical quantity conversion units 178_1 and 178_3 and the effective value current physical quantity conversion units 188_1 and 188_3.

The RMS voltage physical quantity conversion units 178_1 and 178_3 and the RMS current physical quantity conversion units 188_1 and 188_3 do not always have to operate, and when the RMS voltage V1rms and V3rms and the RMS current I1rms and I3rms are requested. Therefore, the calculation amount can be reduced.
Because of the above configuration, it has high measurement accuracy, can handle a wide range of deviations in amplitude and phase of the voltage conversion circuit and current conversion circuit, and can be realized even in an H / W configuration with low calculation capability by reducing the amount of calculation performed constantly. Further, since the adjustment values V1a, V3a, I1a, I3a, W1a, W3a, Var1a, and Var3a are all set from the outside, the memory capacity can be reduced as compared with the self-adjustment inside.

Embodiment 7 FIG.
Embodiment 7 of the present invention will be described below. FIG. 21 is a diagram for explaining an adjustment method in the electronic watt-hour meter according to Embodiment 7 of the present invention.
In the seventh embodiment, adjustment is performed by single-phase two-wire connection (voltage is connected in parallel in each phase and current is connected in series in each phase) even in the case of a polyphase meter (for example, an electronic watt-hour meter). Since it is assumed that the voltage and current input to each phase are the same by performing the single-phase two-wire connection, all the calculated values calculated in each phase must be the same. If they are not the same, it is due to variations in the voltage input circuit unit, the current input circuit unit, and the AD converters 110 and 112, and this needs to be corrected. In addition, the imaginary load power supply 381 used for adjustment only needs to be able to output with a single-phase two-wire, and can be configured at a lower cost than the adjustment equipment using the imaginary load power supply 281 of the fourth and fifth embodiments. Further, since it is not necessary to change the connection method by the phase wire type of the electronic watt-hour meter 100 to be adjusted, the adjustment equipment can be made inexpensively and preparation for adjustment becomes easy.

  The following description will be made assuming that a single-phase two-wire connection is made even when the multiphase (for example, three-phase four-wire) electronic watt-hour meter 100 is adjusted. All adjustments are controlled by the PC 384 via the communication I / F 382, and the output of the virtual load power supply 381 can also be controlled from the PC 384 by the communication I / F 382. The PC 384 and the electronic watt-hour meter 100 can communicate with each other through the communication I / F 382.

(1) First, the amplitude balance and phase balance of each phase are adjusted.
The imaginary load power supply 381 is controlled from the PC 384 via the communication I / F 382, and the power with the rated power and the power factor of 0.5 is applied. Here, the power factor can be other than 0.5. However, if a power factor having a large data change in the power and reactive power with respect to the phase change is selected, the accuracy of phase adjustment is improved. Is desirable.

  Here, the power metering buffer unit 191 (191_1, 191_2 (not shown), 191_3) and the reactive power communication buffer unit 195 (195_1, 195_2 (195_2) of each phase are transmitted from the electronic watt-hour meter 100 via the communication I / F 382. (Not shown) Data is taken into the PC 384 from 195_3). The data of the power communication buffer unit 191 for each phase is W1, W2, and W3, and the data of the reactive power communication buffer unit 195 for each phase is var1, var2, and var3. Since the single-phase two-wire connection is used, the input voltage and current are the same in each phase, and the coordinates represented by (W1, var1), (W2, var2), (W3, var3) must be the same. I must. Adjust the coefficients of the amplitude phase correctors 130 (130_1, 130_2 (not shown), 130_3) of each phase so that the coordinates of the other phases coincide with the coordinates of one phase, for example, so that the above coordinates are the same. To do. Here, the coefficients of the amplitude phase corrector for each phase are α1, β1, α2, β2, α3, β3.

  For example, when the coordinates of two phases are matched with the coordinates of one phase, it is as follows. Note that the coefficients of the amplitude phase corrector 130 at the time when the coordinate point is acquired from the electronic watt-hour meter 100 are described as α1, α2, α3 = 1, β1, β2, β3 = 0, Even if the coefficient is another value, it is easy to match the coordinates.

１相の座標に対する２相の座標の振幅比Gain12は、

となる。よって、２相の振幅位相補正器のα２，β２に、
α２＝Gain12×cos（Δθ12）、β２＝Gain12×sin（Δθ12）
をＰＣ３８４から通信Ｉ／Ｆ３８２を介して電子式電力量計１００に設定する。 The phase difference Δθ12 between the coordinates of one phase and the coordinates of two phases is

The amplitude ratio Gain12 of the two-phase coordinates to the one-phase coordinates is

It becomes. Therefore, α2 and β2 of the two-phase amplitude phase corrector
α2 = Gain12 × cos (Δθ12), β2 = Gain12 × sin (Δθ12)
Is set in the electronic watt-hour meter 100 from the PC 384 via the communication I / F 382.

としてもよい。
上記と同様にして、ＰＣ３８４から通信Ｉ／Ｆ３８２を介して補正が必要な相の振幅位相補正器１３０の係数α１，α２，α３、β１，β２，β３を設定することで、各相の振幅バラツキ、位相バラツキを調整することができる。 Also, using Equation 3,

It is good.
Similarly to the above, by setting the coefficients α1, α2, α3, β1, β2, and β3 of the amplitude phase corrector 130 of the phase that needs to be corrected from the PC 384 via the communication I / F 382, the amplitude variation of each phase is set. The phase variation can be adjusted.

(2) Next, the rated load of the electric energy is adjusted.
The imaginary load power supply 381 is controlled from the PC 384 via the communication I / F 382, and the power having the rated power and the power factor of 1.0 is applied. The rated load adjustment of the electric energy is based on a relative comparison between the pulse output from the electric energy pulse output unit 136 of the electronic wattmeter 100 and the pulse output from the master meter 386. The relative comparison of the pulses may be adjusted by the ratio of the pulse count number output from the electronic watt-hour meter 100 output at a fixed time and the pulse count number output from the master meter 386, or the electronic power You may adjust by the ratio of the pulse frequency output from the quantity meter 100 and the pulse frequency output from the master meter 386.

In the electronic watt-hour meter 100 of the seventh embodiment, the electric energy and reactive electric energy output from the electric energy pulse output unit 136 are the above (W1, var1), (W2, var2), (W3 , Var3), the power amount rated reference value (threshold value for outputting a power amount pulse) and the reactive power amount rated reference value (threshold value for outputting a reactive power amount pulse). For example, when the phase wire system is a single-phase three-wire system, the total power of 1 phase, 3 phases, and the total reactive power of 1 phase and 3 phases are added for each sampling frequency, so that the energy pulse and reactive energy The frequency of the pulse is
Electric energy pulse frequency = {(W1 + W3)
× Sampling frequency} (Formula 13)
/ Power amount rated reference value reactive power amount pulse frequency = {(var1 + var3)
× Sampling frequency} (Formula 14)
/ Reactive energy rating reference value. Therefore, based on the data acquired by the communication I / F 382, the pulse frequency of the electronic watt-hour meter (adjusted device) 100 is calculated by the PC 384, and the pulse frequency of the master meter 386 and the electronic watt-hour meter ( The power amount rated reference value and the reactive power amount rated reference value can be set so that the pulse frequency of the to-be-adjusted device 100 becomes the same.

Electricity rating standard value = Electricity rating standard value
× {Pulse frequency of electronic watt-hour meter (Formula 15)
/ Master meter pulse frequency}
Reactive energy rating reference value = Reactive energy rating reference value
× {Pulse frequency of electronic watt-hour meter (Formula 16)
/ Master meter pulse frequency}
As described above, the electric energy rating reference value and the reactive electric energy rating reference value are calculated and set in the electronic watt-hour meter (adjusted device) 100 from the PC 384 via the communication I / F 382. The rated load can be adjusted.

If a 90 ° phase difference is guaranteed between the active power and reactive power by the Hilbert converter, the reactive power rated reference value may be the same value as the power rated reference value, and the amount of calculation can be reduced.
(3) Next, phase adjustment is performed.
The imaginary load power supply 381 is controlled from the PC 384 via the communication I / F 382, and the power with the rated power and the power factor of 0.5 is applied. The phase adjustment is based on a relative comparison between the pulse output from the electric energy pulse output unit 136 of the electronic watt-hour meter 100 and the pulse output from the master meter 364. The relative comparison of the pulses may be adjusted by the ratio of the pulse count number output from the electronic watt-hour meter 100 output at a fixed time and the pulse count number output from the master meter 386, or the electronic power You may adjust by the ratio of the pulse frequency output from the quantity meter 100 and the pulse frequency output from the master meter 386.

  Similarly to the above, the pulse frequency of the electronic watt-hour meter (adjusted device) 100 and the frequency of the master meter 386 are acquired by the PC 384 and the amplitude phase corrector 136 is set so as to be the same as the frequency of the master meter 386. Adjust by changing the coefficient. In addition, since the coefficient of the amplitude phase corrector for each phase has already been adjusted in (1) so as to balance the amplitude and phase of each phase, the coefficient change for each phase is the same phase adjustment amount. .

とする。なおｎは各相を表す。 Assuming that the amplitude phase correction coefficient before phase adjustment of each phase is α_n_pre, β_n_pre, and the amplitude phase correction coefficient after phase adjustment is α_n_new, β_n_new.

And N represents each phase.

Further, if the fact that the power factor of the input power is about 0.5 (not accurate due to the accuracy of the virtual load power supply 381) is used, the phase adjustment amount can be estimated. If the phase of the current electronic watt-hour meter (tuned device) 100 is θ,
(Cos60 ° -cosθ) / cos60 ° = (master meter frequency
-Frequency of electronic watt-hour meter) (Equation 18)
/ Because it is the frequency of the master meter,
θ = arccos
{Frequency of electronic watt-hour meter (Equation 19)
/ (Master meter frequency x 2)}
Thus, it can be estimated that Δφ = 60 ° −θ.
The approximate amount of phase adjustment may be calculated by other methods, and the above approximate method is not the only one.

(4) Next, a physical quantity conversion coefficient is set.
The imaginary load power supply 381 is controlled from the PC 384 via the communication I / F 382, and the power having the rated power and the power factor of 1.0 is applied. The physical quantity conversion coefficients (W1a, W2a, W3a, Var1a, Var2a, Var3a) are set by comparison with the calculation result of the high-precision reference multimeter 388.
Obtains calculation results of RMS voltage V1rms, V2rms, V3rms, RMS current I1rms, I2rms, I3rms, power W1, W2, W3, Var1, Var2, and Var3 from PC 384 via communication I / F 382. To do. Also, the effective value voltage communication buffer unit 174 (174_1, 174_2 (not shown), 174_3) of each phase and the effective value current communication buffer of each phase from the electronic wattmeter 100 from the PC 384 via the communication I / F 382. Unit 184 (184_1, 184_2 (not shown), 184_3), and power communication buffer units 191 (191_1, 191_2 (not shown), 191_3) and 195 (195_1, 195_2 (not shown), 195_3) of each phase , V2rms, V3rms, I1rms, I2rms, I3rms, W1, W2, W3, Var1, Var2, Var3.

  The physical quantity conversion coefficient is set in the electronic watt-hour meter (adjusted device) 100 from the PC 384 via the communication I / F 382 as (calculation result of reference multimeter / data of communication buffer). In the effective value voltage and the effective value current, the physical quantity conversion coefficient is set for each phase, and the balance of amplitude is also adjusted. In the power, since the amplitude and phase of each phase have already been adjusted, it is not necessary to set a physical quantity conversion coefficient for each phase, and all may be the same value.

The reactive power physical quantity conversion coefficient is desirably input by inputting rated power and power factor 0 from the imaginary load power supply 381, but it is guaranteed that the phase difference between current and voltage is 90 ° by Hilbert conversion. If it is, there is no problem with the same physical quantity conversion coefficient of power.
Therefore, since it can adjust similarly to a single phase meter also in a multiphase meter, an adjustment routine can be made common regardless of a phase wire type. Further, in the multi-phase meter, it is not necessary to input the rated power, power factor 1.0, rated power, and power factor 0.5 for each phase, so that the adjustment equipment can be simplified and the adjustment time can be shortened.

  The electronic watt-hour meter 100 according to the seventh embodiment is configured such that all adjustment values can be set from the outside. Therefore, as disclosed in JP-A-11-64402, for each phase. Needless to say, it is also possible to input and adjust the rated power, power factor 1.0 and rated power, power factor 0.5.

Embodiment 8 FIG.
In the seventh embodiment, the case where only the energy pulse and the reactive energy pulse can be obtained from the master meter 386 has been described. However, when the master meter 386 having the circuit shown in FIG. 20 is used, the adjustment is simpler. Become.
Note that the master meter 386 is adjusted in advance by another high-precision master meter (not shown).

  The imaginary load power supply 381 is controlled from the PC 384 via the communication I / F 382, and the power with the rated power and the power factor of 0.5 is applied. Here, the power factor can be other than 0.5. However, if a power factor having a large data change in the power and reactive power with respect to the change in phase is selected, the accuracy of phase adjustment is increased. desirable.

  Here, via the communication I / F 382, the power communication buffer unit 191 (191_1, 191_2 (not shown), 191_3) and the reactive power communication buffer unit of each phase of the electronic watt-hour meter (adjusted device) 100 are provided. Data of 195 (195_1, 195_2 (not shown), 195_3) is taken into the PC 384. Further, the data of the power communication buffer unit 191 of each phase and the reactive power communication buffer unit 195 of each phase are taken into the PC 384 from the master meter 386 via the communication I / F 382. Since the single-phase, two-wire connection is used, the input voltage and current are the same in each phase, so the coordinates represented by (W1, var1), (W2, var2), (W3, var3) are the same. Since the master meter 386 must be pre-adjusted, the above coordinates are the same. Therefore, the amplitude phase corrector 130 (130_1, 130_1,...) Of each phase of the electronic watt-hour meter (adjusted device) 100 is set so that the coordinates of the electronic watt-hour meter (tuned device) 100 coincide with the coordinates of the master meter 386. 130_2 (not shown) and 130_3) are adjusted. The calculation of the coefficient is the same as (1) of the seventh embodiment.

Furthermore, since the above coordinates are already in agreement with the master meter 386, the rated load adjustment can be performed by reading the rated reference value of the master meter 386 and setting it as it is in the electronic watt-hour meter (adjusted device) 100. Good. Similarly, the physical quantity conversion coefficient of the master meter 386 may be set as it is for the physical quantity conversion coefficient of power and the physical quantity conversion coefficient of reactive power.
The effective value voltage and the effective value current are adjusted in the same manner as in the fourth embodiment (4).

According to the above procedure, adjustment when the circuit of the present invention (the circuit shown in FIG. 20) is used for the master meter 386 can be performed with high accuracy and at high speed.
Note that the adjustment when the circuit of the present invention (the circuit shown in FIG. 20) is used for the master meter 386 only needs to match the coordinates of each phase with the master meter 386. Therefore, single-phase two-wire connection is not essential. Needless to say, other connections are also possible.

  The present invention can be applied to an electronic watt-hour meter that performs A / D conversion of current and voltage to measure the amount of power and an error adjustment method thereof. In addition, a power calculation circuit that calculates power from current and voltage converted into digital values includes a device that calculates at least one of power, reactive power, power amount, and reactive power amount, and power and reactive power. The present invention can be applied to a device that calculates a correction value of phase and amplitude based on the above.

FIG. 1 is a block diagram of an electronic watt-hour meter according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing the amplitude / phase corrector of FIG.
FIG. 3 is a diagram showing a modification of the amplitude / phase corrector of FIG.
FIG. 4 is a diagram showing a modified example of the amplitude / phase corrector of FIG.
FIG. 5 is a diagram for explaining the concept of amplitude / phase correction of FIG.
FIG. 6 is a block diagram of an electronic watt-hour meter according to Embodiment 2 of the present invention.
FIG. 7 is a flowchart for explaining the operation of the self-corrector of FIG.
FIG. 8 is a diagram for explaining the concept of amplitude / phase correction of FIG.
FIG. 9 is a block diagram of an electronic watt-hour meter according to Embodiment 3 of the present invention.
FIG. 10 is a block diagram of a three-phase four-wire electronic watt-hour meter according to Embodiment 4 of the present invention.
FIG. 11 is a diagram showing an adjustment flow of the electronic watt-hour meter of FIG.
FIG. 12 is a diagram showing a flow of balance adjustment in the electronic watt-hour meter of FIG.
FIG. 13 is a diagram showing a flow of phase adjustment in the electronic watt-hour meter of FIG.
FIG. 14 is a diagram showing a flow of full adjustment in the electronic watt-hour meter of FIG.
FIG. 15 is a vector diagram showing the relationship between active power and reactive power during phase adjustment in the electronic watt-hour meter of FIG.
FIG. 16 is a vector diagram showing the relationship between active power and reactive power during power metering in the electronic watt-hour meter of FIG.
FIG. 17 is a diagram showing the relationship between the threshold value and the electric energy pulse in the electronic watt-hour meter of FIG.
FIG. 18 is a flowchart for explaining current measurement in the electronic watt-hour meter of FIG.
FIG. 19 is a block diagram of an electronic watt-hour meter according to Embodiment 5 of the present invention.
FIG. 20 is a block diagram of an electronic watt-hour meter according to Embodiment 6 of the present invention.
FIG. 21 is a diagram for explaining adjustment in an electronic watt-hour meter according to Embodiment 7 of the present invention.
FIG. 22 is a block diagram showing a conventional electronic watt-hour meter.

Explanation of symbols

  100 is an electronic watt-hour meter, 102 is a power calculation circuit, 110 is an A / D converter, 112 is an A / D converter, 120 is a Hilbert transform in-phase A, 122 is a Hilbert transformer quadrature, and 124 is a Hilbert transform in-phase B, 126 is a multiplier, 128 is a multiplier, 130 is an amplitude / phase correction value, 132 is an external correction unit, 134 is an electric energy meter, 136 is an electric energy pulse output device, 138 is an electric energy indicator, 140 is Two-dimensional amplitude / phase corrector, 150 is a self-corrector, 152 is a true value storage unit, 170 is an effective value calculator, 174 is a communication buffer, 180 is an effective value calculator, 184 is a communication buffer, 191 is a communication buffer, 194 is a communication buffer, 200 is an electronic watt-hour meter, 221 is a current transformer, 222 is a transformer, 223 is a current conversion circuit, 224 is a voltage conversion circuit, 224 is an effective value current calculation unit, 22 Is an effective value voltage calculation unit, 231 is a current balance adjustment calculation unit, 232 is a voltage balance adjustment calculation unit, 234 is a balance adjustment value calculation unit, 241 is an active power multiplier, 242 is a Hilbert transformer, and 243 is a reactive power multiplier. 244 is a phase adjustment value calculation unit, 245 is a digital low-pass filter, 246 is a digital low-pass filter, 247 is an adder, 248 is an adder, 251 is an active power amount / frequency converter, and 252 is a reactive power amount / frequency converter. 253 is a full adjustment value calculation unit, 254 is an oscillation circuit, 255 is a calculation control unit, 261 is a counter, 271 is a display, 272 is an adjustment switch, 273 is an EEPROM, 281 is a virtual load power supply, 290 is V, I measurement , 310 is a balance fine adjustment value calculation unit, 312 is a current balance fine adjustment calculation unit, and 314 is a voltage balance fine adjustment operation. Parts, 381 imaginary load power supply, 382 communication I / F, 384 are PC, 386 is a master meter, reference multimeter 388.

Claims (11)

A voltage conversion circuit for A / D converting the voltage transformed by the transformer into a digital value;
A current conversion circuit for A / D converting the current transformed by the current transformer into a digital value;
A first voltage phase converter that converts the phase of the output of the voltage converter circuit by a first angle;
A second voltage phase converter for phase-converting the output of the voltage converter circuit by a second angle;
A current phase converter for phase-converting the output of the current converter circuit by the first angle;
An active power calculator that multiplies the outputs of the first voltage phase converter and the current phase converter to determine the active power ( x ) before correction ;
A reactive power calculator that multiplies the outputs of the second voltage phase converter and the current phase converter to obtain a reactive power before correction ( y ) including a reactive power component;
Input the active power ( x ) and reactive power ( y ) before correction , and the phase difference of the voltage with respect to the current on the primary side of the transformer and the current transformer and the voltage with respect to the current after A / D conversion The phase shift (φ) with respect to the phase difference, the reciprocal (A) of the ratio (amplitude shift) of the amplitude and amplitude of the current and voltage on the primary side of the transformer and current transformer and the current and voltage after A / D conversion. And an amplitude / phase correction unit that outputs the corrected effective power ( x ′ ) and reactive power ( y ′ ) corrected by the amplitude / phase corrector shown in Equation 1 ,
An electric energy metering unit for integrating the output of the amplitude / phase correction unit and measuring the electric energy;
An electronic watt-hour meter, comprising: an electric energy indicator that displays the electric energy measured by the electric energy meter.

The amplitude / phase correction unit
When a voltage of known amplitude and phase and a current of known amplitude and phase are input from the power supply for adjustment to the transformer and current transformer,
While obtaining the active power and reactive power before correction obtained by the active power calculator and the reactive power calculator based on the input of the adjustment power supply,
Correction factors for phase shift and amplitude shift based on the effective power and reactive power before correction and the theoretical active power and reactive power obtained from the known voltage, the known current and the second angle. electronic power meter of claim 1 Symbol placement and obtaining the. The amplitude / phase correction unit
When an adjustment current of the same current is input to each phase by the adjustment power supply, the output value output from one current conversion circuit is stored, and the output value output from another current conversion circuit is A reference current storage unit that stores a coefficient divided by the output value output from the current conversion circuit of
When the adjustment voltage of the same voltage is input to each phase by the adjustment power supply, the output value output from one voltage conversion circuit is stored and the output value output from another voltage conversion circuit is A reference voltage storage unit that stores a coefficient divided by an output value output from one voltage conversion circuit, and a coefficient stored in the reference current storage unit at the output of the other current conversion circuit when measuring the amount of electric power. The balance adjustment unit according to claim 1, further comprising: a balance adjustment unit that multiplies the output of the other voltage conversion circuit by a coefficient stored in the reference voltage storage unit to balance the output of each phase. Electronic energy meter. An adjustment current storage unit for storing an adjustment current input from the adjustment power supply;
When the adjustment current of the same current is input to each phase by the adjustment power supply, the output value output from one current conversion circuit is stored, and the output value output from another current conversion circuit is stored as described above. A reference current storage unit that stores a coefficient divided by an output value output from one current conversion circuit, an output value output from the current conversion circuit of each phase when measuring electric energy, and the adjustment current storage unit Current measurement for obtaining the current of each phase based on the adjustment current stored in the output current, the output value output from one current conversion circuit stored in the reference current storage unit, and the coefficient of each phase The electronic watt-hour meter according to claim 1 or 3, further comprising: 5. The electronic watt-hour meter according to claim 4 , wherein the fine adjustment of the coefficient after storing the coefficient is adjusted by a current downstream of the current measuring unit. An adjustment voltage storage unit for storing an adjustment voltage input from the adjustment power supply;
When the adjustment voltage of the same voltage is input to each phase by the adjustment power supply, the output value output from one voltage conversion circuit is stored and the output value output from another voltage conversion circuit is A reference voltage storage unit for storing a coefficient divided by an output value output from one voltage conversion circuit, an output value output from the voltage conversion circuit for each phase at the time of measuring electric energy, and the adjustment voltage storage unit Voltage measurement for determining the voltage of each phase based on the adjustment voltage stored in the reference voltage, the output value output from one voltage conversion circuit stored in the reference voltage storage unit, and the coefficient of each phase The electronic watt-hour meter as described in any one of Claims 1 and 3-5 characterized by the above-mentioned. The electric energy metering unit calculates the electric energy by time integrating the output from the amplitude / phase correcting unit, and outputs a pulse every time the electric energy reaches a threshold value,
A rated storage unit that stores a rated current, a rated voltage, a phase wire type, an instrument constant that determines the number of pulses to be output for a measured electric energy, and a sampling frequency of A / D conversion;
Obtain the theoretical period of the pulse generated by the power meter when the rated power is input from the rated current, rated voltage, phase wire type, and meter constant input from the above rated memory, and the rated power is input. The number of output bits per sampling from the amplitude / phase correction unit is detected, and a value obtained by multiplying the number of bits by the sampling frequency input from the rated storage unit and the theoretical period is used as a threshold value. The electronic watt-hour meter according to claim 1, further comprising a full adjustment value calculation unit for setting. The electronic power meter according to claim 2 , wherein the power supply for adjustment outputs power having a rated voltage, a rated current, and a power factor of 1.0. The electronic watt-hour meter according to claim 1, wherein the difference between the first angle and the second angle is 90 degrees, and the reactive power is reactive power. A voltage conversion circuit for A / D converting the voltage transformed by the transformer into a digital value;
A current conversion circuit for A / D converting the current transformed by the current transformer into a digital value;
A voltage phase converter for phase-converting the output of the voltage converter circuit by a first angle;
A first current phase converter for phase-converting the output of the current converter circuit by the first angle;
A second current phase converter for phase-converting the output of the current converter circuit by a second angle;
An active power calculator that multiplies the outputs of the voltage phase converter and the first current phase converter to determine the active power ( x ) before correction ;
A reactive power calculator that multiplies the outputs of the voltage phase converter and the second current phase converter to obtain a reactive power ( y ) before correction including a reactive power component;
Input the active power ( x ) and reactive power ( y ) before correction , and the phase difference of the voltage with respect to the current on the primary side of the transformer and the current transformer and the voltage with respect to the current after A / D conversion The phase shift (φ) from the phase difference, the reciprocal (A) of the ratio (amplitude shift) of the amplitude and amplitude of the current and voltage on the primary side of the transformer and the current transformer and the current and voltage after A / D conversion. And an amplitude / phase correction unit that outputs the corrected effective power ( x ′ ) and reactive power ( y ′ ) corrected by the amplitude / phase corrector shown in Equation 1 ,
An electric energy metering unit for integrating the output of the amplitude / phase correction unit and measuring the electric energy;
An electronic watt-hour meter, comprising: an electric energy indicator that displays the electric energy measured by the electric energy meter.

A voltage input unit for inputting a digitally converted voltage;
A current input unit for inputting a digitally converted current;
A first voltage phase conversion unit for phase converting the output of the voltage input unit by a first angle;
A second voltage phase converter for phase-converting the output of the voltage converter by a second angle;
A current phase converter for phase-converting the output of the current converter by the first angle;
An active power calculator that multiplies the outputs of the first voltage phase converter and the current phase converter to determine the active power ( x ) before correction ;
A reactive power calculator that multiplies the outputs of the second voltage phase converter and the current phase converter to obtain a reactive power before correction ( y ) including a reactive power component;
Input the active power ( x ) and reactive power ( y ) before correction , and the phase difference of the voltage with respect to the current on the primary side of the transformer and the current transformer and the voltage with respect to the current after A / D conversion Phase shift with respect to phase difference (φ) and reciprocal number (A) of the ratio (amplitude shift) of current and voltage on the primary side of the transformer and current transformer and the amplitude of current and voltage after A / D conversion And an amplitude / phase correction unit that outputs the corrected effective power ( x ′ ) and reactive power ( y ′ ) after being corrected by the amplitude / phase corrector shown in Formula 1 . A power arithmetic circuit characterized by the above.

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