JP3830095B2 - Three-phase imbalance suppression method for distribution system - Google Patents

Three-phase imbalance suppression method for distribution system Download PDF

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JP3830095B2
JP3830095B2 JP2002148696A JP2002148696A JP3830095B2 JP 3830095 B2 JP3830095 B2 JP 3830095B2 JP 2002148696 A JP2002148696 A JP 2002148696A JP 2002148696 A JP2002148696 A JP 2002148696A JP 3830095 B2 JP3830095 B2 JP 3830095B2
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voltage
adjustment device
reactive power
power adjustment
phase
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JP2003348755A (en
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靖臣 豊田
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NGK Insulators Ltd
Energy Support Corp
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Energy Support Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/10—Flexible AC transmission systems [FACTS]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks

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Description

【０００１】
【発明の属する技術分野】
本発明は、静止型無効電力調整装置を利用した配電系統の三相不平衡抑制方法に関するものである。
【０００２】
【従来の技術】
静止型無効電力調整装置（ＳＶＧ：Static Var Generator）は、図１に示すように進み位相を与えるコンデンサ１とインバータ２と、遅れ位相を与える連系リアクトル３とからなるものである。この静止型無効電力調整装置は配電系統４に並列に接続され、負荷５の変動によって生じる系統の電圧変動を打ち消す電圧調整器として用いられている。
【０００３】
このため静止型無効電力調整装置は配電系統４の電流と電圧とを検出できる電流・電圧センサ６を備え、系統に発生した無効電力を検出するとともに、制御回路７の指令により、検出された無効電力を打ち消すことができる進み位相または遅れ位相の電力を配電系統４に供給して系統電圧（正相電圧）を一定に保っている。このように静止型無効電力調整装置は電圧一定制御方式により運転されるのが普通であるが、系統の力率を常に一定に保つことを目的として、力率一定制御方式による運転も行なわれている。
【０００４】
しかし配電系統４においては、上記した正相電圧の変動の他に、特定の二相間に負荷が集中的に接続される等の原因によって三相不平衡電圧が発生することがあり、これに伴って逆相電圧が発生する。そこでこの逆相電圧を抑制するための専用の三相不平衡電力出力変換器も提案されているが、電圧調整用に機器のほかに新たに三相不平衡電力出力変換器を設置しなければならず、設備費用が嵩むという問題があった。
【０００５】
【発明が解決しようとする課題】
本発明は上記した従来の問題点を解決して、電圧一定制御または力率一定制御のために使用されている静止型無効電力調整装置を利用して、配電系統の三相不平衡電圧を抑制する方法を提供するためになされたものである。
【０００６】
【課題を解決するための手段】
上記の課題を解決するためになされた第１の発明は、配電系統に電流・電圧センサと静止型無効電力調整装置とを接続し、電流・電圧センサによる測定値から三相間の逆相電圧を演算し、演算された逆相電圧を打ち消す電力を静止型無効電力調整装置から配電系統に出力することにより、三相不平衡電圧を抑制する三相不平衡抑制方法であって、静止型無効電力調整装置を電圧一定制御方式により運転しつつ、検出された正相電圧と電圧設定値との偏差をなくすに要する静止型無効電力調整装置の正相電圧対応分の出力Ｑａを定格出力から差し引いた静止型無効電力調整装置の出力の余力の範囲内で、三相不平衡電圧を抑制することを特徴とするものである。なお、静止型無効電力調整装置の平均出力量に応じて電圧一定制御の電圧設定値を経時的変更し、静止型無効電力調整装置の出力の余力分を確保することが好ましい。
【０００７】
また第２の発明は、配電系統に電流・電圧センサと静止型無効電力調整装置とを接続し、電流・電圧センサによる測定値から三相間の逆相電圧を演算し、演算された逆相電圧を打ち消す電力を静止型無効電力調整装置から配電系統に出力することにより、三相不平衡電圧を抑制する三相不平衡抑制方法であって、静止型無効電力調整装置を力率一定制御方式により運転しつつ、検出された力率と力率設定値との偏差をなくすに要する静止型無効電力調整装置の正相電圧対応分の出力Ｑａを定格出力から差し引いた静止型無効電力調整装置の出力の余力の範囲内で、三相不平衡電圧を抑制することを特徴とするものである。
【０００８】
このように本発明によれば、常時は電圧一定制御または力率一定制御のために使用されている静止型無効電力調整装置の余力を利用して、三相間の逆相電圧を打ち消す電力を系統に供給し、配電系統の三相不平衡電圧を抑制することができるので、静止型無効電力調整装置とは別に専用の三相不平衡電力出力変換器を系統に設置する必要はない。
【０００９】
【発明の実施の形態】
以下に本発明の好ましい実施形態を示す。
本発明で用いられる装置構成は図１に示したとおりであり、従来と特に変わるところはない。しかし制御回路７に組み込まれた制御ソフトの内容が異なるので、以下に詳細に説明する。このように本発明は、既存の静止型無効電力調整装置の制御ソフトを変更するだけで容易に実施することができる。
【００１０】
先ず図２は静止型無効電力調整装置を電圧一定制御方式で運転する場合の制御系統図であり、制御回路７は電流・電圧センサ６により検出された各相の電圧から従来と同様に正相電圧（系統電圧）を演算するとともに、三相不平衡の原因である逆相電圧をも演算する。なお図３に示すように、不平衡な三相電圧は正相電圧と逆相電圧とのベクトル和として表すことができる。検出された正相電圧は従来と同様に電圧設定値と比較され、制御回路７はそれらの間の偏差をなくすように静止型無効電力調整装置の出力Ｑａを算出する。
【００１１】
またこれと同時に、制御回路７は演算された逆相電圧を打ち消すことができる静止型無効電力調整装置の出力Ｚｂを算出する。そしてこの出力Ｚｂを前記の出力Ｑａと合成した出力指令を静止型無効電力調整装置に与える。これを受けた静止型無効電力調整装置は合成された出力量の電力を配電系統４に出力し、系統電圧を一定に維持しながら同時に三相不平衡を解消することができる。ただし合成した出力量が静止型無効電力調整装置の定格出力を越えると、正相電圧対応分の出力Ｑａの一部が削減されるおそれがあり、静止型無効電力調整装置の本来の役割である系統電圧を一定に維持することが達成できなくなる。
【００１２】
そこで好ましくは、合成に先立ち静止型無効電力調整装置の定格出力から正相電圧対応分の出力Ｑａを差し引き、静止型無効電力調整装置の余力を算出する。そして出力Ｚｂがその余力の範囲内にあればそのまま出力Ｚｂを出力Ｑａと合成する。しかし出力Ｚｂが余力を越える場合には、その余力の限度内で逆相電圧を打ち消すように出力Ｚｂを制限する。この場合には静止型無効電力調整装置は系統電圧を一定に維持することはできるが、三相不平衡を完全には解消することはできず、余力に応じて三相不平衡抑制効果を発揮することとなる。
【００１３】
このように静止型無効電力調整装置の出力に十分な余裕がない場合には、三相不平衡の抑制効果が低減することとなる。そこで請求項２に示すように、静止型無効電力調整装置の平均出力量に応じて電圧一定制御の電圧設定値を経時的に変更し、静止型無効電力調整装置の出力の余力分を確保することが好ましい。
【００１４】
図４はそのための制御フローの一例を示すものであり、サンプリング時間ＴS中の静止型無効電力調整装置の無効電力出力量ＱΣの平均値Σ＝ＱΣ/ＴSを算出し、その値を上限設定値QHや下限設定値ＱLと比較する。そして平均値Σがこれらの設定値の範囲内にあれば電圧設定値ＶCはそのままとするが、これらの設定値の範囲を外れる場合には静止型無効電力調整装置の出力に余裕がないことを意味するため、電圧設定値ＶCを所定のＶSずつ段階的に変化させる。
【００１５】
図５はその動作例を示すグラフであり、当初は静止型無効電力調整装置の出力は０ｋＶａｒであるが、負荷の急激な変動により静止型無効電力調整装置の出力が瞬間的に−３００ｋＶａｒ付近まで増加している。しかしその後、電圧設定値ＶCを例えば１００Ｖずつ低下させることによって静止型無効電力調整装置の出力を次第に減少させ、静止型無効電力調整装置の出力の余力を確保する。なお、そのままでは系統電圧は低下したままとなるが、その状態が所定時間（例えば４５秒）続くと、配電系統に設けられている自動電圧調整器（ＳＶＲ: Step Voltage Regulator）のタップが切り替えられ、系統電圧は上昇して元に戻るので問題はない。
【００１６】
上記したように、電圧一定制御を行なう場合には静止型無効電力調整装置の平均出力量に応じて電圧設定値を経時的に変更し、静止型無効電力調整装置の出力の余力分を確保することによって、三相不平衡を打ち消すための出力を可能としておくことが好ましい。なおこの場合にも瞬間的な系統電圧の変化に対しては、静止型無効電力調整装置は迅速に対応することができる。
【００１７】
図６は静止型無効電力調整装置を力率一定制御方式で運転する場合の制御系統図である。この場合には、電流・電圧センサ６により検出された各相の電流・電圧から制御回路１０は力率を算出し、力率設定値をもとに静止型無効電力調整装置の出力Ｑａを算出する。これと同時に制御回路１０は検出された逆相電圧を打ち消すことができる静止型無効電力調整装置の出力Ｚｂを算出する。そしてこの出力Ｚｂを出力Ｑａと合成した出力指令を静止型無効電力調整装置に与える。これにより静止型無効電力調整装置は系統の力率を一定に維持しながら、同時に三相不平衡電圧を抑制することができる。
【００１８】
ただし合成した出力が静止型無効電力調整装置の定格出力を越えると、静止型無効電力調整装置の本来の役割である力率を一定に維持できなくなる。そこでこの場合にも前記の電圧一定制御の場合と同様、合成に先立ち静止型無効電力調整装置の定格出力から正相電圧対応分の出力Ｑａを差し引き、静止型無効電力調整装置の余力を算出する。そして出力Ｚｂがその余力の範囲内にあればそのまま出力Ｚｂを出力Ｑａと合成する。しかし出力Ｚｂが余力を越える場合には、その余力の限度内で逆相電圧を打ち消すように出力Ｚｂを制限することが好ましい。
【００１９】
【実施例】
図７〜図１０に本発明の比較例と実施例を示す。この実施例は、系統電圧６６００Ｖの配電系統に取付けた静止型無効電力調整装置（最大出力±３００ｋＶａｒ）の制御内容を様々に変更した場合の、相間電圧と不平衡率とを示したグラフである。図７のグラフは比較例を示し、静止型無効電力調整装置の運転を停止した場合の実測値である。横軸の１秒の時点で不平衡負荷を投入することにより、ｕ-ｗとｖ-ｗの２相間の電圧が大きく低下すると同時に、不平衡率が４％を越えていることが判る。
【００２０】
図８のグラフは、静止型無効電力調整装置に不平衡抑制機能のみを発揮させた場合の実測値であり、不平衡負荷を投入しても不平衡率は直ぐに０％に戻るが、相間の電圧は全て６２００Ｖにまで低下したままとなっている。しかし図９のグラフに示すように電圧一定制御を行ないつつ不平衡抑制機能を発揮させるようにすれば、相間電圧は全体的にわずかに低下するものの３相間とも全て一致しており、不平衡率は０％に維持される。さらに図１０のグラフに示すように、力率一定制御を行ないつつ不平衡抑制機能を発揮させるようにした場合にも、同様の好ましい結果が得られることが確認された。
【００２１】
【発明の効果】
以上に説明したように、本発明によれば電圧一定制御または力率一定制御のために使用されている静止型無効電力調整装置を利用して、配電系統の三相不平衡電圧を抑制することができ、三相不平衡を抑制するための特別な設備を設置する必要がないため、設備コストがかからない。また本発明によれば静止型無効電力調整装置の取付点よりも下流側のみならず、上流側についても三相不平衡抑制効果を及ぼすことができるため、多数の機器を配電系統に設置する必要もないなどの利点がある。
【００２２】
【図面の簡単な説明】
【図１】本発明で用いられる装置構成を示すブロック図である。
【図２】静止型無効電力調整装置を電圧一定制御方式で運転する場合の制御系統図である。
【図３】不平衡な三相電圧のベクトル図である。
【図４】請求項２の発明の制御フローを示すブロック図である。
【図５】請求項２の発明の動作例を示すグラフである。
【図６】静止型無効電力調整装置を力率一定制御方式で運転する場合の制御系統図である。
【図７】静止型無効電力調整装置の運転を停止した場合の相間電圧と不平衡との変化を示すグラフである。
【図８】静止型無効電力調整装置に不平衡抑制機能を発揮させた場合の相間電圧と不平衡との変化を示すグラフである。
【図９】静止型無効電力調整装置に電圧一定制御を行ないつつ不平衡抑制機能を発揮させた場合の相間電圧と不平衡との変化を示すグラフである。
【図１０】静止型無効電力調整装置に力率一定制御を行ないつつ不平衡抑制機能を発揮させた場合の相間電圧と不平衡との変化を示すグラフである。
【符号の説明】
１ コンデンサ、２ インバータ、３ リアクトル、４ 配電系統、５ 負荷、６ 電流・電圧センサ、７ 制御回路[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-phase unbalance suppression method for a distribution system using a static reactive power adjustment device.
[0002]
[Prior art]
As shown in FIG. 1, a static reactive power adjustment device (SVG: Static Var Generator) is composed of a capacitor 1 that gives a leading phase, an inverter 2, and a linked reactor 3 that gives a lagging phase. This static reactive power adjustment device is connected in parallel to the power distribution system 4 and is used as a voltage regulator that cancels voltage fluctuations in the system caused by fluctuations in the load 5.
[0003]
For this reason, the static reactive power adjustment device includes a current / voltage sensor 6 that can detect the current and voltage of the distribution system 4, detects reactive power generated in the system, and detects the reactive power detected by a command from the control circuit 7. The power of the leading phase or the lagging phase that can cancel the power is supplied to the power distribution system 4 to keep the system voltage (positive phase voltage) constant. As described above, the static reactive power adjustment device is normally operated by the constant voltage control method, but for the purpose of keeping the power factor of the system constant at all times, the operation is also performed by the constant power factor control method. Yes.
[0004]
However, in the distribution system 4, in addition to the fluctuation of the positive phase voltage described above, a three-phase unbalanced voltage may be generated due to a load being intensively connected between two specific phases. Negative phase voltage is generated. Therefore, a dedicated three-phase unbalanced power output converter has also been proposed to suppress this negative-phase voltage, but a new three-phase unbalanced power output converter must be installed in addition to the equipment for voltage regulation. In other words, there was a problem that the equipment cost increased.
[0005]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems and suppresses the three-phase unbalanced voltage of the distribution system by using a static reactive power adjustment device used for constant voltage control or constant power factor control. It was made to provide a way to do that.
[0006]
[Means for Solving the Problems]
A first invention made to solve the above problem is to connect a current / voltage sensor and a static reactive power adjustment device to a distribution system, and to calculate a reverse phase voltage between three phases from a measurement value by the current / voltage sensor. A three-phase unbalance suppression method that suppresses three-phase unbalanced voltage by calculating and outputting power that cancels the calculated negative-phase voltage from the static-type reactive power adjustment device to the distribution system. While operating the regulator using the constant voltage control method, the output Qa corresponding to the positive phase voltage of the static reactive power regulator required to eliminate the deviation between the detected positive phase voltage and the voltage set value was subtracted from the rated output. The three-phase unbalanced voltage is suppressed within the range of the remaining capacity of the output of the static reactive power adjustment device . In addition, it is preferable to change the voltage setting value of the constant voltage control over time according to the average output amount of the static reactive power adjustment device, and to secure the remaining capacity of the output of the static reactive power adjustment device.
[0007]
The second aspect of the invention connects a current / voltage sensor and a static reactive power adjustment device to a power distribution system, calculates a reverse phase voltage between three phases from a measured value by the current / voltage sensor, and calculates the calculated reverse phase voltage. Is a three-phase unbalance suppression method that suppresses the three-phase unbalance voltage by outputting the power to cancel the power to the distribution system from the static reactive power adjustment device, and the static reactive power adjustment device is controlled by a constant power factor control method. The output of the static reactive power adjustment device obtained by subtracting the output Qa corresponding to the positive phase voltage of the static reactive power adjustment device required to eliminate the deviation between the detected power factor and the power factor set value while operating. The three-phase unbalanced voltage is suppressed within the range of the remaining power.
[0008]
As described above, according to the present invention, the power for canceling the reverse phase voltage between the three phases is utilized using the remaining power of the static reactive power adjustment device that is normally used for constant voltage control or constant power factor control. Since the three-phase unbalanced voltage of the distribution system can be suppressed, it is not necessary to install a dedicated three-phase unbalanced power output converter in the system separately from the static reactive power adjustment device.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention are shown below.
The apparatus configuration used in the present invention is as shown in FIG. 1 and is not particularly different from the conventional one. However, since the content of the control software incorporated in the control circuit 7 is different, it will be described in detail below. As described above, the present invention can be easily implemented only by changing the control software of the existing static reactive power adjustment device.
[0010]
First, FIG. 2 is a control system diagram in the case where the static reactive power adjustment device is operated by the constant voltage control method. In addition to calculating the voltage (system voltage), it also calculates the reverse-phase voltage that causes the three-phase imbalance. As shown in FIG. 3, an unbalanced three-phase voltage can be expressed as a vector sum of a positive-phase voltage and a negative-phase voltage. The detected positive phase voltage is compared with the voltage set value as in the conventional case, and the control circuit 7 calculates the output Qa of the static reactive power adjustment device so as to eliminate the deviation between them.
[0011]
At the same time, the control circuit 7 calculates the output Zb of the static reactive power adjustment device that can cancel the calculated reverse phase voltage. Then, an output command obtained by combining the output Zb with the output Qa is given to the static reactive power adjustment device. Receiving this, the static reactive power adjustment device outputs the combined output amount of power to the distribution system 4, and can simultaneously eliminate the three-phase imbalance while maintaining the system voltage constant. However, if the combined output exceeds the rated output of the static reactive power adjustment device, part of the output Qa corresponding to the positive phase voltage may be reduced, which is the original role of the static reactive power adjustment device. Maintaining a constant system voltage cannot be achieved.
[0012]
Therefore, preferably, prior to synthesis, the output Qa corresponding to the positive phase voltage is subtracted from the rated output of the static reactive power adjustment device to calculate the remaining capacity of the static reactive power adjustment device. If the output Zb is within the remaining power range, the output Zb is directly combined with the output Qa. However, when the output Zb exceeds the surplus power, the output Zb is limited so as to cancel the reverse phase voltage within the limit of the surplus power. In this case, the static reactive power adjustment device can maintain the system voltage constant, but it cannot completely eliminate the three-phase unbalance, and exhibits a three-phase unbalance suppression effect according to the remaining power. Will be.
[0013]
Thus, when there is not enough margin in the output of the static reactive power adjustment device, the effect of suppressing the three-phase unbalance is reduced. Therefore , as shown in claim 2, the voltage setting value of the constant voltage control is changed over time according to the average output amount of the static reactive power adjustment device, and the remaining power of the output of the static reactive power adjustment device is secured. It is preferable.
[0014]
FIG. 4 shows an example of a control flow for the, an average value Σ = Q Σ / T S of the reactive power output quantity Q sigma of static reactive power regulator device during the sampling time T S, the value Is compared with the upper limit set value QH and the lower limit set value Q L. If the average value Σ is within the range of these set values, the voltage set value V C is left as it is. However, if the average value Σ is out of the range of these set values, there is no margin in the output of the static reactive power adjustment device. Therefore, the voltage setting value V C is changed step by step by a predetermined V S.
[0015]
FIG. 5 is a graph showing an example of the operation. Initially, the output of the static reactive power adjustment device is 0 kVar, but the output of the static reactive power adjustment device instantaneously reaches around −300 kVar due to a sudden change in the load. It has increased. However, the output of the static reactive power adjustment device is gradually reduced by decreasing the voltage set value V C by, for example, 100 V, and the remaining output of the static reactive power adjustment device is ensured. In addition, the system voltage remains lowered as it is, but when the state continues for a predetermined time (for example, 45 seconds), the tap of the automatic voltage regulator (SVR: Step Voltage Regulator) provided in the distribution system is switched. There is no problem because the system voltage rises and returns.
[0016]
As described above, when performing constant voltage control, the voltage setting value is changed over time according to the average output amount of the static reactive power adjustment device, and the remaining power of the static reactive power adjustment device is secured. Thus, it is preferable to enable output for canceling the three-phase imbalance. In this case as well, the static reactive power adjustment device can quickly respond to instantaneous changes in the system voltage.
[0017]
FIG. 6 is a control system diagram when the static reactive power adjustment device is operated by the constant power factor control method. In this case, the control circuit 10 calculates the power factor from the current / voltage of each phase detected by the current / voltage sensor 6, and calculates the output Qa of the static reactive power adjustment device based on the power factor setting value. To do. At the same time, the control circuit 10 calculates the output Zb of the static reactive power adjustment device that can cancel the detected negative phase voltage. Then, an output command obtained by combining the output Zb with the output Qa is given to the static reactive power adjustment device. As a result, the static reactive power adjustment device can simultaneously suppress the three-phase unbalanced voltage while maintaining the power factor of the system constant.
[0018]
However, if the combined output exceeds the rated output of the static reactive power adjustment device, the power factor that is the original role of the static reactive power adjustment device cannot be maintained constant. Therefore, in this case as well, as in the case of the constant voltage control described above, the output Qa corresponding to the positive phase voltage is subtracted from the rated output of the static reactive power adjustment device prior to synthesis to calculate the remaining power of the static reactive power adjustment device. . If the output Zb is within the remaining power range, the output Zb is directly combined with the output Qa. However, when the output Zb exceeds the surplus power, it is preferable to limit the output Zb so as to cancel the reverse phase voltage within the limit of the surplus power.
[0019]
【Example】
7 to 10 show comparative examples and examples of the present invention. This example is a graph showing the interphase voltage and the unbalance rate when the control contents of a static reactive power adjustment device (maximum output ± 300 kVar) attached to a distribution system with a system voltage of 6600 V are variously changed. . The graph of FIG. 7 shows a comparative example, and is an actual measurement value when the operation of the static reactive power adjustment device is stopped. It can be seen that by applying an unbalanced load at 1 second on the horizontal axis, the voltage between the two phases u-w and v-w is greatly reduced, and at the same time, the unbalance rate exceeds 4%.
[0020]
The graph of FIG. 8 is an actual measurement value when only the unbalance suppression function is exerted on the static reactive power adjustment device. Even when an unbalanced load is applied, the unbalance rate immediately returns to 0%. All voltages remain reduced to 6200V. However, as shown in the graph of FIG. 9, if the unbalance suppression function is performed while performing constant voltage control, the interphase voltage decreases slightly overall, but all three phases are in agreement, and the unbalance rate Is maintained at 0%. Furthermore, as shown in the graph of FIG. 10, it was confirmed that the same preferable result can be obtained even when the unbalance suppression function is performed while performing the constant power factor control.
[0021]
【The invention's effect】
As explained above, according to the present invention, the static reactive power adjustment device used for constant voltage control or constant power factor control is used to suppress the three-phase unbalanced voltage of the distribution system. Since there is no need to install special equipment for suppressing three-phase imbalance, there is no equipment cost. In addition, according to the present invention, it is possible to exert a three-phase imbalance suppression effect not only on the downstream side but also on the upstream side of the attachment point of the static reactive power adjustment device, so it is necessary to install a large number of devices in the power distribution system. There are advantages such as not.
[0022]
[Brief description of the drawings]
FIG. 1 is a block diagram showing an apparatus configuration used in the present invention.
FIG. 2 is a control system diagram when the static reactive power adjustment device is operated by a constant voltage control method.
FIG. 3 is a vector diagram of an unbalanced three-phase voltage.
FIG. 4 is a block diagram showing a control flow of the invention of claim 2 ;
FIG. 5 is a graph showing an operation example of the invention of claim 2 ;
FIG. 6 is a control system diagram when the static reactive power adjustment device is operated by a constant power factor control method.
FIG. 7 is a graph showing changes in interphase voltage and unbalance when the operation of the static reactive power adjustment device is stopped.
FIG. 8 is a graph showing a change between an interphase voltage and an unbalance when the static reactive power adjustment device exhibits an unbalance suppression function.
FIG. 9 is a graph showing a change between the interphase voltage and the unbalance when the static reactive power adjustment device performs the constant voltage control and exhibits the unbalance suppression function.
FIG. 10 is a graph showing the change between the interphase voltage and the unbalance when the static reactive power adjustment device performs the unbalance suppression function while performing constant power factor control.
[Explanation of symbols]
1 Capacitor, 2 Inverter, 3 Reactor, 4 Distribution system, 5 Load, 6 Current / voltage sensor, 7 Control circuit

Claims (3)

配電系統に電流・電圧センサと静止型無効電力調整装置とを接続し、電流・電圧センサによる測定値から三相間の逆相電圧を演算し、演算された逆相電圧を打ち消す電力を静止型無効電力調整装置から配電系統に出力することにより、三相不平衡電圧を抑制する三相不平衡抑制方法であって、静止型無効電力調整装置を電圧一定制御方式により運転しつつ、検出された正相電圧と電圧設定値との偏差をなくすに要する静止型無効電力調整装置の正相電圧対応分の出力Ｑａを定格出力から差し引いた静止型無効電力調整装置の出力の余力の範囲内で、三相不平衡電圧を抑制することを特徴とする配電系統の三相不平衡抑制方法。Connect the current / voltage sensor and static reactive power adjustment device to the power distribution system, calculate the negative phase voltage between the three phases from the measured value by the current / voltage sensor, and static power to cancel the calculated negative phase voltage A three-phase unbalance suppression method that suppresses a three-phase unbalance voltage by outputting to a power distribution system from a power conditioner , wherein the detected positive voltage is detected while operating the static reactive power conditioner by a constant voltage control method. The output Qa corresponding to the positive phase voltage of the static reactive power adjustment device required to eliminate the deviation between the phase voltage and the voltage setting value is within the range of the remaining power of the static reactive power adjustment device obtained by subtracting the output Qa from the rated output. A method for suppressing a three-phase unbalance in a distribution system, characterized by suppressing a phase unbalance voltage . 静止型無効電力調整装置の平均出力量に応じて電圧一定制御の電圧設定値を経時的に変更し、静止型無効電力調整装置の出力の余力分を確保する請求項１記載の配電系統の三相不平衡抑制方法。 3. The distribution system according to claim 1, wherein a voltage setting value of constant voltage control is changed over time according to the average output amount of the static reactive power adjustment device to secure a remaining amount of output of the static reactive power adjustment device. Phase imbalance suppression method. 配電系統に電流・電圧センサと静止型無効電力調整装置とを接続し、電流・電圧センサによる測定値から三相間の逆相電圧を演算し、演算された逆相電圧を打ち消す電力を静止型無効電力調整装置から配電系統に出力することにより、三相不平衡電圧を抑制する三相不平衡抑制方法であって、静止型無効電力調整装置を力率一定制御方式により運転しつつ、検出された力率と力率設定値との偏差をなくすに要する静止型無効電力調整装置の正相電圧対応分の出力Ｑａを定格出力から差し引いた静止型無効電力調整装置の出力の余力の範囲内で、三相不平衡電圧を抑制することを特徴とする配電系統の三相不平衡抑制方法。 Connect the current / voltage sensor and static reactive power adjustment device to the power distribution system, calculate the negative phase voltage between the three phases from the measured value by the current / voltage sensor, and static power to cancel the calculated negative phase voltage A three-phase unbalance suppression method that suppresses a three-phase unbalance voltage by outputting to a power distribution system from a power adjustment device, which is detected while operating a static reactive power adjustment device by a constant power factor control method. Within the range of the remaining capacity of the output of the static type reactive power adjustment device obtained by subtracting the output Qa corresponding to the positive phase voltage of the static type reactive power adjustment device required to eliminate the deviation between the power factor and the power factor set value from the rated output, A three-phase unbalance suppression method for a distribution system, characterized by suppressing a three-phase unbalance voltage .
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