JPS61155866A - Reactive power transducer - Google Patents

Abstract

PURPOSE:To perform transducing operation without any influence of a voltage unbalance among voltages of respective phases by providing an integration circuit, variable amplifying circuit, amplification degree control circuit, etc., and using a transfer for both a single-phase system and a polyphase system. CONSTITUTION:The integration circuit 20, variable amplifying circuit 21, amplitude degree limiting circuit 27, etc., are provided. A voltage signal ev to be measured is phase-delayed by 90 deg. through the circuit 20 and sent to the circuit 21, and the signal em1 obtained from the signal ev by smoothing 25 and the signal em2 obtained from the signal ev inputted from the circuit 21 by smoothing 26 and supplied to the circuit 27 to generate the amplification degree control signal ed of the circuit 21, which is supplied to the circuit 21. Then, a voltage signal ec outputted by the circuit 21 multiplied by the voltage signal of a voltage signal ia to be measured to obtain a voltage signal e0 proportional to reactive power. Therefore, the signal e0 is obtained even by the single-mode system. For a polyphase system, transducers are only connected for respective phases. Thus, even if a voltage unbalance among respective phases is generated, an accurate voltage signal of reactive power for each phase is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ineffective quadrature transducer that can be used even in a single-phase system.

[Technical background of the invention]

FIG. 3 is a configuration diagram of a conventional three-phase three-wire reactive quadrupole transducer. As is well known, reactive power Q is expressed as voltage e,
When the current is {circle around (1)} and the phase difference between voltage and current is θ, it is expressed as Q-el·sin θ-e)-CO8(θ-90°) (1). Therefore, the reactive power Q can be obtained by multiplying the voltage signal e with a 90' phase delay by the current ■. Therefore, in the transducer shown in FIG. 3, each voltage signal e1.03 on the 1-element side and the 3-element side is combined at an appropriate ratio to generate each voltage signal el.

e IL , e 31 with a phase delay of e3 of 90°
A method is used in which reactive power is obtained by creating voltage signals and multiplying these voltage signals el' and e3' by corresponding current signals fl and i2.

Specifically, on the 1-element side, the amplifier 1 converts the 1-element side voltage el input from the voltage input terminal 2 into (1/2>
Furthermore, the three-element side voltage e3 inputted from the voltage input terminal 4 is multiplied by 11 by the amplifier 3 provided on the three-element side, and added to the adder circuit 5 and added. As a result, the adder circuit 5 outputs the 1-element side voltage e1 to 9
A voltage signal ea with a 0° phase delay is output and sent to the multiplier circuit 6. Further, the one-element side current: 1 is converted into a voltage signal eia by a current-voltage conversion circuit (hereinafter referred to as an I/V conversion circuit) 7 and sent to a multiplication circuit 6. Thus, the output voltage e1m of the multiplier circuit 6 is el m-ea -e i a-cos θ
= e1 ・cos (θ-90)・■1-81 1tl
sin θ, and the voltage signal e17F is proportional to the reactive power on one element side.
L is obtained.

On the other hand, on the 3-element side, as shown in FIG. 4(b), the voltage signal e
In order to obtain the voltage signal eb delayed by 90 degrees from the voltage signal eb, the adder circuit 10
A voltage signal eb delayed by 90 degrees is output from the multiplier 12, and this signal eb and the voltage signal eib from the I/V conversion circuit 11 are added to the multiplier circuit 12. A proportional voltage signal 33m is obtained. Then, each output voltage signal e of the multiplier 61 and the multiplier 12
1 m and 83 m are added, smoothed by a smoothing circuit 13, converted to low impedance by an output circuit 14, and outputted from an output terminal 15 as a voltage signal corresponding to three-phase three-wire reactive power.

(Problems in the background art) However, in the above transducer, each voltage signal e
In order to delay the phase of 1 and e3 by 90 degrees, the voltage signal e3 of the 3-element side is input to the other phase, for example, the 1-element side. Therefore, if the voltage signal levels on the 1st element side and the 3rd element side are the same, that is, not in a balanced state, the accuracy will be 9.
The voltage of the reactive power obtained when 0 degree phase delay is no longer possible.

The signal ends up containing errors. Furthermore, it also has the disadvantage of being influenced by other phases. Further, current transducers for reactive power are for three-phase (polyphase) as in the above configuration, and there are no transducers for single-phase reactive power. This is because there was a problem with the phase delay of 90 degrees with the voltage signal, and for measurement purposes, one for single-phase reactive power is required.

[Purpose of the invention]

The present invention was made based on the above-mentioned circumstances, and its purpose is to be able to be used not only in a single-phase system but also in a multi-phase system, without being affected by voltage unbalance of each phase. An object of the present invention is to provide a reactive quadrupole transducer that can accurately convert.

(Summary of the Invention) The present invention shifts the phase of a voltage signal under test by 90 degrees using an integrating circuit or a differentiating circuit, and variably amplifies it to a predetermined level using a variable amplifier circuit. The output signal is compared with the rectified signal, and an amplification control signal is given from the amplification control circuit to the variable amplifier circuit, and the output signal of the variable amplifier circuit and the current signal to be measured are multiplied to obtain a reactive power signal. It is a reactive quadrature transducer.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a reactive quadrupole transducer according to the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a reactive current quadrature transducer according to the present invention. In the figure, reference numeral 20 denotes an integrating circuit, which delays the phase of the voltage signal ev to be measured by 90 degrees in order to obtain reactive power.

Specifically, the operational amplifier 3 to which the feedback capacitor C1 is connected
81 and an input resistor R1. Reference numeral 21 denotes a variable amplifier circuit which variably amplifies the integrated voltage signal es outputted from the integrating circuit 20 to a predetermined level and outputs it. operational amplifier A2 connected to
and an input resistor R2. The voltage signal ev to be measured and the voltage signal eC output from the variable amplifier circuit 21 are each connected to an ideal diode circuit, ie, a rectifier circuit 23.
24 and a smoothing circuit 25 consisting of an OR passive integrator.
．． 26 and is sent to the amplification control circuit 27. This amplification degree control circuit 27 calculates the difference between the rectified and smoothed voltage signal em1 to be measured and the voltage signal em2, and further performs integration to create an amplification degree control signal ed for the variable amplification circuit 21. . Specifically, it is composed of an operational amplifier A3 to which a return capacitor C2 is connected and an input resistor R3, and specifically, the voltage signal eml output from the smoothing circuit 25 corresponding to the voltage signal to be measured ev is calculated. The voltage signal em2, which is input to one input terminal of the amplifier A3 and output from the smoothing circuit 26 corresponding to the voltage signal eC, is input to the slave input terminal.

On the other hand, the I/V conversion circuit 28 converts the measured current signal ia into a voltage signal according to its value, and the converted voltage signal is sent to the multiplier circuit 29 together with the voltage signal ec output from the variable amplifier circuit 21. It is ready to be sent. This multiplier circuit 29 multiplies each input voltage signal and outputs a voltage signal eO proportional to the reactive power. This output voltage signal eO is sent via a smoothing circuit 30 to an output circuit 31 that performs low impedance conversion and output to the outside.

Next, the operation of the transducer configured as described above will be explained with reference to the operation timing diagram shown in FIG.

When the measured voltage signal ev as shown in the figure is applied,
The integrating circuit 20 outputs a voltage signal e whose phase is delayed by 90°.
S is output. Here, if the voltage signal ev to be measured is es-Esin(1)t, the voltage signal eS output from the integrating circuit 20 is expressed by the following equation. That is, -(-1/R1CI)Jsinωt = (E/ωRI C1)cosωt -(-1/ωRICI) xs in (ωt -π/2)
=(2). As can be seen from equation (2), the voltage signal eS has a phase of π/2 (90 degrees) with respect to ev.
Although it is delayed, it can be seen that the amplitude is affected by the angular velocity ω. Therefore, the amplitude is controlled by the variable amplifier circuit 21 to create a signal that is not affected by the angular velocity ω. That is, the rectifier circuit 23 rectifies the voltage signal ev to be measured to obtain a rectified output eml, and the smoothing circuit 25 further obtains a smoothed voltage signal eml.

On the other hand, the voltage signal eS output from the integrating circuit 20 is amplified by the variable amplifier circuit 21 and sent to the rectifier circuit 24.
This rectifier circuit 24 rectifies the voltage signal ec as output em2.
is further smoothed by the smoothing circuit 26 to obtain a voltage signal em
Get 2. The voltage signals eml and em2 output from each smoothing circuit 25 and em2 are both output from the amplification control circuit 2.
7, and the amplification control circuit 27 receives each voltage signal e.
The difference between m1 and em2 is determined and integrated to create an amplification control signal ed, which is output to the voltage controlled variable resistor 22 of the variable amplifier circuit 21. Here, the amplification degree control signal ed increases in the initial state. Therefore, in the initial state, the resistance value of the voltage-controlled variable resistor 22 is small, and the degree of amplification as the variable amplifier circuit 21 is low. As a result, the amplitude of the voltage signal ec output from the variable amplifier circuit 21 becomes small.

Then, each voltage signal em input to the amplification control circuit 27
When the levels of l and em2 become the same, the amplification control signal ed output from the amplification control circuit 27 becomes constant.

Note that this voltage signal ed is ed--Es i n (ω
t-(π/2))...(3) Further, as shown in FIG. 2, when the angular velocity ω increases after time T1, the amplification degree control signal ed decreases by the amount of change in the angular velocity ω. As a result, the voltage signal ec becomes unaffected by the angular velocity ω. In this way, the voltage signal ec and the voltage signal of the current signal to be measured ia outputted from the I/V conversion circuit 28 are multiplied by the multiplier circuit 29, and a voltage signal eO proportional to the reactive power is obtained. Then, this voltage signal eo is outputted to the outside from the output circuit 31 via the smoothing circuit 30.

In this way, in the above embodiment, the voltage to be measured e
The integrator circuit 20 delays the phase of the voltage signal ev by 90 degrees and sends it to the variable amplifier circuit 21, and the amplification degree control circuit 27 to create an amplification degree control signal ed for the variable amplifier circuit 21 and give it to the variable amplifier circuit 21,
Therefore, the voltage signal ec output from the variable amplifier circuit 21
Since the voltage signal eo proportional to the reactive power is obtained by multiplying by the voltage signal of the measured voltage signal ia, the voltage signal eo proportional to the reactive power can be accurately obtained even in a single phase. Therefore, when applied to a polyphase system, by connecting the transducer for each phase, a voltage signal proportional to the reactive power can be obtained for each phase. In this case, since each phase is separate, it will not be affected by other phases, and therefore,
Even if voltage imbalance occurs between phases, accurate reactive power voltage signals can be obtained for each phase.

Note that the present invention is not limited to the above embodiment. For example, the smoothing circuits 25 and 26 may be replaced with amplitude detection circuits such as peak hold circuits. Also, a differentiating circuit is connected in place of the integrating circuit 20 to advance the phase by 90 degrees, and an inverting circuit is connected to the output terminal of the variable amplifier circuit 21 to invert the output and send it to the calculation circuit 29. Good too.

〔Effect of the invention〕

According to the present invention, the voltage signal to be measured is phase-shifted by 90 degrees by the integrating circuit or the differentiating circuit, and is variably amplified by the variable amplifier circuit, and the voltage signal to be measured and the output signal of the variable amplifier circuit are output from the amplification degree control circuit. An amplification control signal is created and sent to the variable amplifier circuit, and the output signal of the variable amplifier circuit and the measured l! Since the current signal is multiplied by the current signal to obtain a voltage signal proportional to the reactive power, it can be used in single-phase systems as well as multi-phase systems, and can be converted accurately without being affected by voltage imbalance of each phase. It is possible to provide a reactive quadrupole transducer that can be used.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a reactive quadrupole transducer according to the present invention, FIG. 2 is an operation timing diagram of the transducer shown in FIG. 1, and FIG. 3 is a conventional reactive quadrupler transducer. Figure 4 (a) (b) is a schematic % formula for determining reactive power. Figure 4 (a) (b) Procedural amendment written by Showa Hiroshi O-q. 24th, Commissioner of the Patent Office, Manabu Shiga. 1. Indication of the case Patent Application No. 1982-274612 2. Name of the invention Reactive power transducer 3. Person making the amendment Relationship to the case Patent applicant (307) Toshiba Corporation 4. Agent 6. Amendment Subject specification, drawing 7, contents of amendment (1) Change “voltage signal eb to ~each amplification degree” on page 3, line 14 to line 15 of the specification to “in order to obtain voltage signal eb, amplifier 8 is 1x, and amplifier 9 to 11/2x amplification." (2) In the same book, page 4, line 18, "voltage signal" is corrected to "voltage signal". (3) In the same IIF, page 9, lines 1 to 9, ``In other words, the rectifier circuit 23 obtains the voltage signal eml.'' is corrected to the following sentence. That is, the voltage signal to be measured 6v is rectified by the rectifier circuit 23 to obtain a rectified output en, and the voltage signal em is further smoothed by the smoothing circuit 25. get. On the other hand, the voltage signal es output from the integrating circuit 20 is amplified by the variable amplifier circuit 21 and sent to the rectifier circuit 24.
This rectifier circuit 24 rectifies the voltage signal ec and outputs emu
is further smoothed by the smoothing circuit 26 to obtain a voltage signal en
get d. (4) In the same book, page 10, lines 4 to 7, ``Note: This voltage signal cd is...'' is corrected to the following sentence. The voltage signal ec at this time is ec--Bsln(ω1-(π/2))...
3) It becomes. (5) Figure 2 of the drawing is corrected as shown in the attached sheet.

Claims (1)

[Claims] an integrating circuit or differentiating circuit that inputs a voltage signal to be measured and shifts the phase by 90 degrees; a variable amplifier circuit that variably amplifies the output of the integrating circuit or differentiating circuit to a predetermined level; an amplification control circuit that integrates the difference between the output signal of the variable amplification circuit and the rectified signal to create an amplification control signal of the variable amplification circuit; A reactive power transducer comprising: a reactive power output circuit that outputs a reactive power signal using a reactive power output circuit.