JPS5935153A - Electronic type power measuring apparatus - Google Patents

Abstract

PURPOSE:To attain to reduce the number of parts and the number of adjusting processes and to enhance the preciseness and the reliability of the titled apparatus, by using a high speed multiple phase shift time sharing system to enable the measurement available and unavailable electric energy by one time sharing multiply circuit. CONSTITUTION:A signal ev proportional to the load voltage of a current supply wire taken out by a transformer 21 for a measuring instrument divided into two branches and one of them is introduced into the side of the switch part S of a switch circuit S1 while the other is introduced into the other switch part S' in a state delaying a phase by pi/2 by a phase shift circuit 23. Because the switch parts S, S' are alternately turned on and off by the high speed time sharing pulse from a time sharing pulse distributor 24, signals ev, e'v are alternately supplied to a pulse width modulation circuit 22 by the operation of the circuit S1. The circuit 22 performs pulse width modulation by using the signals ev, e'v to fabricate a pulse width duty cycle signal which is, in turn, introduced into a time sharing multiply circuit 28. This circuit 28 takes in a signal ei proportional to the consumption current of a power supply line to perform the multiplication of ev, ei, e'v, e'i. This signal is converted to pulse frequency to display available and unavailable electric energy by display parts 35, 36.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronic power measuring device for measuring active power and reactive power.

[Technical background of the invention]

Conventionally, this type of energy is measured using separate active energy meters and reactive energy meters. As shown in Fig. 1, the active energy meter modulates the pulse width with 1H e which is proportional to the load voltage of the electric wire taken out by the instrument transformer 1. a pulse width modulation circuit 2 that creates a pulse width duty cycle signal; and a current-voltage conversion element 4 that converts a signal ei proportional to the current consumption of the feeder line taken out by the instrument current transformer 3 into a voltage signal. , a time division multiplication circuit 5 which performs time division multiplication by taking in a voltage signal ei proportional to the consumption current while selectively turning on and off the analog switch according to the pulse width duty cycle signal, and an output of this circuit 5. After integrating the pulse frequency in an integrating circuit 6 and converting it into a voltage, a v-p conversion circuit 7 converts it into a Cruz frequency, and a next display section that divides this pulse frequency in a frequency dividing circuit 8 and displays it as active energy. 9
It is made up of.

On the other hand, in the reactive energy meter, as shown in FIG. 1.
The configuration is such that the amount of reactive power can be measured by shifting the phase difference between the signals ev and e proportional to the load voltage and current consumption by 7 as a result. In the figure, reference numeral 12 denotes a light indicator that displays the amount of reactive power.

[Problems with background technology]

However, with the above-mentioned power measurement means, active energy is measured with an active energy meter, and reactive energy is measured with a reactive energy meter that is completely different from the active energy meter, so both It is very inconvenient to handle when measuring the amount of electricity, and when installed on a power monitoring panel, the installation scale is not large and it is necessary to electrically adjust each electricity meter in the nest. Therefore, there is a problem that the number of adjustment steps increases.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and uses a high-speed multiple phase shift time division method to enable measurement of active and reactive power amounts with one time division multiplier circuit, thereby reducing the number of parts and adjustment man-hours. The present invention also aims to provide an electronic power measuring device that is highly accurate and reliable.

[Summary of the invention]

The present invention provides a time division/bus pulse divider, and controls the first switch circuit with high-speed time division pulses that are outputted from the divider in multiple numbers to generate a signal proportional to the load voltage of the power supply line and this signal.
A pulse width duty cycle signal for obtaining active power and reactive power is created by alternately introducing the signals with the phase shifted by A signal proportional to the current consumption of the electric wire is input to perform a multiplication operation, and the multiplication result is used to control two sets of second switch circuits using the high-speed time division pulse to calculate active power and reactive power. The configuration is such that the light is displayed separately.

[Embodiments of the invention]

FIG. 3 is a diagram showing an embodiment of the power measuring device according to the present invention. In the figure, reference numeral 21 denotes an instrument transformer that outputs a signal ev proportional to the load voltage of the power supply line. A first switching circuit S1 having two switching sections S and S is interposed, and a phase shift circuit 23 is further provided between the switching section 100 and the transformer 21 with a phase difference of 7. Therefore, with the above configuration, the signal ev proportional to the load voltage of the power supply line and the signal ev' obtained by shifting the phase of this signal by i are alternately taken in by the first switch circuit S1 and introduced into the pulse width modulation circuit 22. Here, the pulse width is modulated by the signal introduced via the switch circuit S1.
This creates an arm pulse width duty cycle signal. Reference numeral 24 denotes a time-division pulse distributor 6-, which generates a high-speed time-division P pulse based on, for example, a clock signal output from a crystal oscillator 25, and outputs a high-speed time-division pulse to the first switch circuit S1 and a second switch circuit S1, which will be described later. It has a function to provide to the switch circuit S2. Reference numeral 26 denotes an instrument current transformer that takes out a signal proportional to the current consumption of the power supply line, and the signal obtained here is converted into a voltage signal ei by a current-voltage conversion element 27 and then sent to a subsequent time division multiplier circuit 28. will be introduced to This time division multiplier circuit 28 is composed of analog switches and the like, and selectively controls the analog switches on and off using the pulse width duty cycle signal output from the pulse width modulation circuit 23 to obtain the voltage signal ei. Then, multiplication operations of ev' at and ev'·e are performed. Furthermore, a second switch circuit S2 is connected to the output side of the time division multiplier circuit 28, and the switch circuit S2 includes electrical switching sections S, 10 and S, τ that perform mutually exclusive operations; One end side of the electrical switching parts S, 100 is commonly connected to one output end of the time division multiplication circuit 28, and one end side of the other electrical switching part S, S is also commonly connected to each other to form the time division multiplication circuit 28. 28, respectively. -j, and the time division multiplier circuit 2 is connected between the other output terminals of the electrical switching parts S and S of the second switch circuit S2.
An integrator circuit 29 for converting the multiplication result of the active power output from the time division multiplication circuit 28 into a voltage signal is connected between the other output terminals of the electrical switching parts 100 and 100. An integrating circuit 30 that converts the power multiplication result into a voltage signal is connected. In the figure, 31.32 is a v-p conversion circuit that converts a voltage signal into a pulse frequency; 33.
34 is a frequency dividing circuit, 35 is an active power amount display section that displays active power amount, and 36 is a reactive power amount display section that displays reactive power amount.

Next, the operation of the device configured as above will be explained.

The signal ev proportional to the load voltage of the power supply line taken out by the instrument transformer 21 is branched into two branches, one of which is directly introduced to the opening/closing part S side of the first switch circuit S, and the other is transferred. The phase is delayed by 7 in the phase circuit 23 and introduced into the other switching section 100. Here, since each opening/closing section S, S of the first switch circuit S1 is alternately turned on and off by the high-speed time division/main pulse from the time division pulse distributor 24, the operation of the first switch circuit S1 Signals e and ev' having a phase lag of signals e and i are alternately supplied to the pulse width modulation circuit 22. As a result, the pulse width modulation circuit 2
2, first pulse width modulation is performed using the signal ev to create a pulse width duty cycle signal, which is introduced into the time division multiplier circuit 28, followed by pulse width modulation using the signal ev' and the same process is performed. A four pulse width duty cycle signal is generated and introduced into the time division multiplication circuit 28. Here, the time-division multiplication circuit 28 takes in a signal θ1 proportional to the current consumption of the power supply line as a Nockles width duty cycle signal corresponding to the signal ev, and performs time-division multiplication of 6 v'at.

At this time, the opening/closing part S of the second switch circuit S2.

Since S is closed, the multiplication result of the time division multiplication circuit 28 passes through the opening/closing parts S and S, is converted into a voltage signal by the integrating circuit 9-29, and is converted into a pulse frequency by the v-p conversion circuit 31. The active power amount is displayed on the display unit 35. Next, when the pulse width duty cycle signal corresponding to the signal e4 is introduced into the time division multiplication circuit 28, the signal ei proportional to the current consumption of the feeder line is similarly taken in and multiplied by ev'·ei. Output the multiplication result. At this time, the opening/closing parts i and 100 are closed by the high-speed time-division pulses of the time-division Norse distributor 24, so
The multiplication output of the time division multiplication circuit 2B is sent to the integration circuit 30 through the opening/closing parts 100 and 100, where it is converted into a voltage signal. Then, this voltage signal is converted to a frequency of 9 pulses by the V-P conversion circuit 32, and is further divided into channels to display the amount of reactive power on the display section 36. To explain the above operating state with reference to FIG. 4, first, the opening/closing part S of the switch circuit S1 is closed and the signal ev is introduced into the pulse width modulation circuit 22, and a pulse width duty cycle signal is obtained, for example as shown in the figure. Multiply ev-ei between point a and point 0.

=10- Next, the opening/closing part S of the switch circuit S1 closes and the signal ev'
inputs into the pulse width modulation circuit 22, similarly obtains the pulse width duty cycle signal, and outputs e between the point shown in the figure and point d.
Multiply by v'·el. This operation is repeated at high speed using high-speed time-division pulses. Here, ev・e
Since i is a signal proportional to the active power, this signal is
If the frequency is divided appropriately after converting to 9 pulse frequency, the display section 35
You can display the active energy amount. The reactive power amount can also be displayed on the display section 36 by performing signal processing.

Next, FIG. 5 is a diagram in which the device of the present invention is applied to a three-phase, three-wire power device. That is, this device includes two sets of voltage transformers 21a and 21b, and phase shift circuits 23a and 23b, respectively.
and switch circuits 81a and SJb, which transmit signals proportional to the load voltages of the plurality of power supply lines to eva and eva'.
, ev51, evb'. The pulse width modulation circuit 22
A pulse width/data cycle signal is created by introducing the pulse width/data cycle signal, and this signal is sequentially supplied to the time division multiplication circuit 28. At this time, switch S3. S4 is also controlled on and off in a predetermined order. As a result, the time division arithmetic circuit 28 calculates eva・eia, 8v based on the output of the pulse width modulation circuit 22.
Multiplying a"eia"vb"eib, evb"eib is performed to obtain the order of active power on the ■ side→reactive ridge force on the ■side→active power on the ■side→reactive power on the ■side.

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications.

〔Effect of the invention〕

As described in detail above, according to the present invention, a signal proportional to a multi-load voltage and a signal obtained by delaying this signal by 7 phases are received using a high-speed time division method to generate a duty cycle signal with a width of 4 pulses. This signal is used to multiply by a signal proportional to the current consumption to obtain the active power and reactive power, so the active power can be calculated using almost one functional component of the watt-hour meter, excluding the display system. and reactive power amount can be measured.

This not only reduces costs by significantly reducing the number of parts, but also reduces the scale of installation when installed in power monitoring panels, etc., and furthermore, the adjustment work is essentially that of a single power meter. In addition, since signals proportional to the load voltage and current consumption are output from the same transformer and current transformer, the error range can be the same and highly reliable. It is possible to provide an electronic power measurement device that can obtain

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional active energy needle, FIG. 2 is a configuration diagram of a conventional reactive energy meter, and FIG. 3 is a configuration diagram showing an embodiment of an electronic power measurement device according to the present invention. FIG. 4 is a diagram showing the multiplication timing of the present device, and FIG. 5 is a diagram showing the configuration of another invention. 22...Pulse width modulation circuit, 23, 23h. 23b...Phase shift circuit, 24...Time division pulse distributor, Applicant's representative Patent attorney Takehiko Suzue 13- Fig. 2 1 Fig. 4 Fig. 5

Claims (2)

[Claims] (1) A time division/bus pulse distributor that outputs a high-speed time division pulse signal, a first signal proportional to the load voltage of the power supply line, and a second signal whose phase is shifted by 7 from this first signal. means for alternately capturing tJ? by the high-speed time-division pulse signal, and pulse width modulation using the first and second signals captured by this means to obtain the first and second tJ? Create a pulse width duty cycle signal - Create a signal proportional to the current consumption of the power supply line using the pulse width modulation circuit and the first and second pulse width duty cycle signals output from this circuit. A time division multiplication circuit that takes in and performs time division multiplication, and the first and second multiplication outputs output from this time division multiplication circuit are alternately taken in as the high speed time division/flat pulse signal and then converted into a pulse frequency. 1. An electronic power measuring device comprising: 1- a plurality of power amount display means for distinguishing and displaying active power amount and reactive power amount; (2) A time-sharing signal divider that outputs high-speed time-sharing signals, a plurality of first signals proportional to the load voltage of a plurality of power supply lines, and a phase of these plurality of first signals by 7. and the plurality of second signals shifted by the high speed time division A? means for sequentially receiving pulse signals in a predetermined order, and generating a pulse width duty cycle signal by modulating the pulse width with the respective plurality of first and second signals received by these means. a pulse width modulation circuit,
A time-division multiplication circuit that performs time-division multiplication by taking in a predetermined order a plurality of signals proportional to the consumption current taken out from each of a plurality of power supply lines using the pulse width duty cycle signal output from this circuit. Then, the output of this time-division multiplication circuit is alternately taken in by the high-speed time-division pulse signal, converted to a pulse frequency, and displayed as a '4i number to distinguish between active energy and reactive energy. 1. A 3-phase 9-3 wire electronic power measuring device, characterized in that it is equipped with a power amount display means.