JPH01224675A - Electronic watthour meter - Google Patents
Electronic watthour meterInfo
- Publication number
- JPH01224675A JPH01224675A JP63052060A JP5206088A JPH01224675A JP H01224675 A JPH01224675 A JP H01224675A JP 63052060 A JP63052060 A JP 63052060A JP 5206088 A JP5206088 A JP 5206088A JP H01224675 A JPH01224675 A JP H01224675A
- Authority
- JP
- Japan
- Prior art keywords
- circuits
- signals
- signal
- voltage signal
- current signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000010363 phase shift Effects 0.000 claims description 12
- 238000005259 measurement Methods 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 claims 2
- 230000010354 integration Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 230000001934 delay Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は電子式電力量計に関し、特に有効電力量と共に
無効電力量を計測するようにした電子式電力量計に関す
る。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic watt-hour meter, and more particularly to an electronic watt-hour meter that measures reactive energy as well as active energy.
従来のこの種の電子式電力計では、被測定系における電
圧を示す電圧信号及び電流を示す電流信号の両信号を受
けて、両信号同士の乗算結果を積算することにより有効
電力量を示す信号を得、また電圧信号の位相角を90度
遅らせてこれと電流信号との乗算結果を積算することに
より無効電力量を示す信号を得ている。電圧信号の位相
角を遅らせるには、電源の周波数(例えば商用電力では
50あるいは60ヘルツ)において電圧位相を90度遅
らすようにした、−周波用の移相器を使用している。Conventional electronic wattmeters of this type receive both a voltage signal indicating the voltage and a current signal indicating the current in the system being measured, and generate a signal indicating the active energy amount by integrating the multiplication results of both signals. A signal indicating the amount of reactive power is obtained by delaying the phase angle of the voltage signal by 90 degrees and integrating the multiplication results of this and the current signal. To delay the phase angle of the voltage signal, a -frequency phase shifter is used that delays the voltage phase by 90 degrees at the frequency of the power supply (for example, 50 or 60 Hz for commercial power).
上述した従来の電子式電力量計では、無効電力の測定部
に使用している移相器は電源周波数の一周波だけで90
度の移相推移を与えるので、例えばサイリスタ等の制御
開閉素子を使用している被測定系の場合のごとく、電流
信号(あるいは電圧信号)が電源周波数の基本波のみな
らずその高調波も多く含む場合には、移相器が高調波成
分に与える移相角は90度からずれてしまい、無効電力
の測定誤差が大きくなるという問題点がある。In the above-mentioned conventional electronic watt-hour meter, the phase shifter used in the reactive power measuring section has a power supply frequency of 90%.
For example, in the case of a system under test that uses controlled switching elements such as thyristors, the current signal (or voltage signal) contains not only the fundamental wave of the power supply frequency but also many of its harmonics. If it is included, the phase shift angle that the phase shifter gives to the harmonic component will deviate from 90 degrees, resulting in a problem that the measurement error of reactive power will increase.
本発明の目的は、上述の問題点を除去し高調波を生ずる
被測定系に対しても精度良く無効電力を測定し得る電子
式電力量計を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic watt-hour meter that eliminates the above-mentioned problems and can accurately measure reactive power even in systems under test that generate harmonics.
本発明の電力量計は、測定対象の電圧及び電流を示す電
圧信号及び電流信号を受けて該両信号の乗算結果を積算
する有効電力測定手段と、所定の周波数帯域内で実質的
に90度に等しい相対位相差を与える1対の移相回路を
有し前記両号を該移相回路に通して得る1対の出力信号
の乗算結果を積算する無効電力測定手段とを、備えてい
る。The watt-hour meter of the present invention includes an active power measuring means that receives a voltage signal and a current signal indicating the voltage and current of a measurement target and integrates the multiplication results of the two signals, and The reactive power measuring means has a pair of phase shift circuits that give a relative phase difference equal to , and integrates the multiplication results of a pair of output signals obtained by passing both of the above signals through the phase shift circuit.
次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第1図は本発明の第1の実施例を示すブロック図である
。電圧信号及び電流信号はそれぞれ、被測定系の電圧及
び電流を示すアナログ信号である。FIG. 1 is a block diagram showing a first embodiment of the present invention. The voltage signal and current signal are analog signals indicating the voltage and current of the system under test, respectively.
電圧信号は、サンプルホールド回路1において所定のク
ロック周期でサンプルホールドされたあと、アナログ−
ディジタル変換器(ADC)3においてディジタル信号
に変換されて、乗算器5及び移相回路7へ送られる。同
様に電流信号は、サンプルホールド回路2及びADC4
を通りディジタル信号に変換され、乗算器5及び移相回
路8へ送られる。乗算器5の出力信号は電圧信号及び電
流信号の積に対応し、これを積算回路9で積算すること
により有効電力量を示すデータ(有効電力データ)を得
る。移相器7及び8は、所定の帯域幅において位相差を
90度に近似した1対の全域通過形回路(いわゆる90
度移相差回路)である。位相差が90度に近似する帯域
幅を、電源周波数の基本波から所望の次数の高調波まで
含むように設定し、且つ無効電力の測定誤差限度から近
似帯域内での90度移相差の近似誤差限度を算定して、
移相回路7及び8の回路次数を決めである。従って、デ
ィジタル化した電圧信号及び電流信号をそれぞれ移相回
路7及び8に通せば、両信号の基本波成分のみならず高
調波成分まで、実質的に90度に等しい相対的な位相差
を与えることができる。The voltage signal is sampled and held at a predetermined clock cycle in the sample and hold circuit 1, and then converted into an analog signal.
It is converted into a digital signal by a digital converter (ADC) 3 and sent to a multiplier 5 and a phase shift circuit 7. Similarly, the current signal is transmitted to the sample hold circuit 2 and the ADC 4.
The signal is converted into a digital signal and sent to a multiplier 5 and a phase shift circuit 8. The output signal of the multiplier 5 corresponds to the product of the voltage signal and the current signal, and by integrating this in the integration circuit 9, data indicating the amount of active power (active power data) is obtained. The phase shifters 7 and 8 are a pair of all-pass type circuits (so-called 90 degree
degree phase shift difference circuit). Set the bandwidth in which the phase difference approximates 90 degrees to include from the fundamental wave of the power supply frequency to the harmonics of the desired order, and also approximate the 90 degree phase shift difference within the approximation band from the measurement error limit of reactive power. Calculate the error limit and
The circuit orders of phase shift circuits 7 and 8 are determined. Therefore, by passing the digitized voltage signal and current signal through the phase shift circuits 7 and 8, respectively, a relative phase difference substantially equal to 90 degrees is given to not only the fundamental wave component but also the harmonic component of both signals. be able to.
移相回路7及び8の両川力信号を乗算器6で乗算し、こ
れを積算回路10で積算することにより、無効電力量を
示すデータ(無効電力データ)を得る。By multiplying the power signals of both the phase shift circuits 7 and 8 by the multiplier 6 and integrating the multiplied signals by the integrating circuit 10, data indicating the amount of reactive power (reactive power data) is obtained.
本実施例をアナログ形式でも実現できるが、ディジタル
化することにより、回路サイズを小形化でき、特性のば
らつきや経時変化も少くできる。Although this embodiment can be implemented in an analog format, by digitizing it, the circuit size can be made smaller and variations in characteristics and changes over time can be reduced.
第2図は本発明の第2の実施例を示すブロック図である
。本実施例は、第1の実施例(第1図参照)におけるA
DC3及び4のあとに、それぞれ、フィルタ11及び1
2を挿入した構成をもつ。このフィルタ11及び12は
、電圧信号及び電流信号のディジタル化の過程で生じる
オフセットを補正するための高域フィルタである。これ
により、オフセットに起因する測定誤差が生じるのを防
止できる。FIG. 2 is a block diagram showing a second embodiment of the invention. This embodiment is based on A in the first embodiment (see Fig. 1).
After DC3 and 4, filters 11 and 1, respectively.
It has a configuration with 2 inserted. The filters 11 and 12 are high-pass filters for correcting offsets that occur during the digitization process of voltage and current signals. This can prevent measurement errors caused by offsets.
以上説明したように本発明は、電圧及び電流の両信号の
基本波のみならず高調波成分まで90度位相差を与える
ことにより、高調波を生じる被測定系に対しても精度良
く無効電力を測定し得る電子式電力量計を実現できる効
果がある。As explained above, the present invention provides a 90 degree phase difference not only to the fundamental wave but also to the harmonic components of both voltage and current signals, thereby accurately controlling reactive power even in the system under test that generates harmonics. This has the effect of realizing an electronic watt-hour meter that can measure energy.
第1図及び第2図は本発明の実施例のブロック図である
。1 and 2 are block diagrams of embodiments of the present invention.
Claims (3)
信号を受けて該両信号の乗算結果を積算する有効電力測
定手段と、所定の周波数帯域内で実質的に90度に等し
い相対位相差を与える1対の移相回路を有し前記両信号
を該移相回路に通して得る1対の出力信号の乗算結果を
積算する無効電力測定手段とを、備えていることを特徴
とする電子式電力量計。(1) Active power measuring means that receives a voltage signal and a current signal indicating the voltage and current of the measurement target and integrates the multiplication results of both signals, and a relative phase difference that is substantially equal to 90 degrees within a predetermined frequency band. and reactive power measuring means for integrating the multiplication results of the pair of output signals obtained by passing both the signals through the phase shift circuit. Power meter.
それぞれディジタル信号に変換して前記有効電力測定手
段の乗算入力とし且つ前記無効電力測定手段の前記移相
回路の入力とする特許請求の範囲第(1)項記載の電子
式電力量計。(2) The voltage signal and the current signal in analog format are each converted into digital signals to be used as multiplication inputs of the active power measuring means and as inputs of the phase shift circuit of the reactive power measuring means. The electronic watt-hour meter described in (1).
生じるオフセット成分を抑圧するためのフィルタを介設
した特許請求の範囲第(2)項記載の電子式電力量計。(3) The electronic watt-hour meter according to claim (2), further comprising a filter for suppressing offset components generated in the process of conversion after conversion into a digital signal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63052060A JP2856398B2 (en) | 1988-03-04 | 1988-03-04 | Electronic watt-hour meter |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP63052060A JP2856398B2 (en) | 1988-03-04 | 1988-03-04 | Electronic watt-hour meter |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH01224675A true JPH01224675A (en) | 1989-09-07 |
JP2856398B2 JP2856398B2 (en) | 1999-02-10 |
Family
ID=12904270
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP63052060A Expired - Lifetime JP2856398B2 (en) | 1988-03-04 | 1988-03-04 | Electronic watt-hour meter |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2856398B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6496783B1 (en) | 1999-03-05 | 2002-12-17 | Kabushiki Kaisha Toshiba | Electric power calculation system |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS526569A (en) * | 1975-07-07 | 1977-01-19 | Hitachi Ltd | Digital power measuring unit |
JPS5670464A (en) * | 1979-11-15 | 1981-06-12 | Toshiba Corp | Single-phase reactive power converter |
JPS5684564A (en) * | 1979-12-11 | 1981-07-09 | Mitsubishi Electric Corp | Reactive power meter |
JPS57111460A (en) * | 1980-11-17 | 1982-07-10 | Siemens Ag | Electronic type reactive power measuring apparatus |
JPS606877A (en) * | 1983-02-26 | 1985-01-14 | Ohkura Electric Co Ltd | Method and device for detecting reactive power |
JPS62122331A (en) * | 1985-11-21 | 1987-06-03 | Sony Corp | Nonlinear compression device for digital signal |
-
1988
- 1988-03-04 JP JP63052060A patent/JP2856398B2/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS526569A (en) * | 1975-07-07 | 1977-01-19 | Hitachi Ltd | Digital power measuring unit |
JPS5670464A (en) * | 1979-11-15 | 1981-06-12 | Toshiba Corp | Single-phase reactive power converter |
JPS5684564A (en) * | 1979-12-11 | 1981-07-09 | Mitsubishi Electric Corp | Reactive power meter |
JPS57111460A (en) * | 1980-11-17 | 1982-07-10 | Siemens Ag | Electronic type reactive power measuring apparatus |
JPS606877A (en) * | 1983-02-26 | 1985-01-14 | Ohkura Electric Co Ltd | Method and device for detecting reactive power |
JPS62122331A (en) * | 1985-11-21 | 1987-06-03 | Sony Corp | Nonlinear compression device for digital signal |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6496783B1 (en) | 1999-03-05 | 2002-12-17 | Kabushiki Kaisha Toshiba | Electric power calculation system |
Also Published As
Publication number | Publication date |
---|---|
JP2856398B2 (en) | 1999-02-10 |
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