JP3598710B2 - Power system characteristic measurement method - Google Patents
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- JP3598710B2 JP3598710B2 JP3448097A JP3448097A JP3598710B2 JP 3598710 B2 JP3598710 B2 JP 3598710B2 JP 3448097 A JP3448097 A JP 3448097A JP 3448097 A JP3448097 A JP 3448097A JP 3598710 B2 JP3598710 B2 JP 3598710B2
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- 238000000691 measurement method Methods 0.000 title description 8
- 238000000034 method Methods 0.000 claims description 14
- 239000004065 semiconductor Substances 0.000 claims description 9
- 238000005259 measurement Methods 0.000 description 17
- 238000007796 conventional method Methods 0.000 description 1
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Description
【０００１】
【発明の属する技術分野】
本発明は、半導体電力変換装置から電力系統に高調波電流を注入したときの電圧及び電流から系統特性を測定する方法に関する。
【０００２】
【従来の技術】
電力系統の周波数特性等の系統特性を測定するのに、半導体電力変換装置（インバータ）を電力系統に接続し、半導体電力変換装置から系統に高調波電流を注入し、系統連系点における電圧と電流を測定し、これら電圧と電流の振幅比や位相差を求める方法がある。
【０００３】
【発明が解決しようとする課題】
系統電圧は、基本波のみの理想的な正弦波になっておらず、高調波が含まれている。さらに、インバータはその出力電流には指令値による電流の他に連系変圧器の励磁電流などが含まれている。
【０００４】
これら事情から、系統連系点における測定電圧、電流には注入された高調波電流により発生した高調波電圧歪み以外の高調波電圧が含まれており、系統特性を正確に測定するのが難しくなる。
【０００５】
図５〜図７は、インバータから無負荷状態の系統に印加する高調波電流を３Ａ、１Ａ、０．５Ａに変えて系統上位側の特性を測定した結果を示し、各図の（ａ）に従来の測定方法による振幅比Ａｂｓを、（ｂ）に位相差Ａｒｇを高調波次数別に示す。
【０００６】
これら図から分かるように、高調波電流を３Ａ、１Ａ、０．５Ａと変化させた場合、１Ａ及び０．５Ａでは３Ａの場合に比べて、正確に測定されていない。
【０００７】
このように、従来の測定方法では、系統特性を正確に測定するには、大きな高調波電流を注入しなければならない。これに伴って、系統特性測定時の系統連系点の電圧歪みも大きくしてしまう。
【０００８】
本発明の目的は、比較的低い高調波電流の注入で系統特性を正確に測定できる測定方法を提供することにある。
【０００９】
【課題を解決するための手段】
本発明は、系統特性の測定に際して、高調波電流０での電圧と電流を測定し、この測定から系統に存在する外乱成分を各次数別に求めておき、インバータから高調波電流を注入した測定結果から外乱成分を除去することにより、正確な系統特性を測定しようとする方法であり、以下の方法を特徴とする。
【００１０】
半導体電力変換装置から電力系統に高調波電流を注入したときの電圧及び電流から電力系統の特性を測定する方法において、
半導体電力変換装置が系統に注入する高調波電流を０にして系統連系点の電圧と電流を測定し、
前記測定電圧と電流のフーリエ変換係数を電力系統に存在する正弦波及び余弦波の外乱成分として記録しておき、
半導体電力変換装置から電力系統に高調波電流を注入し、このときの連系点の電圧と電流を測定し、
前記測定電圧と電流の次数成分毎に、前記外乱成分を除去した電圧と電流の振幅比と位相差から系統特性を求めることを特徴とする。
【００１１】
【発明の実施の形態】
図１は、本発明の実施形態を示す測定処理手順である。以下、各手順別に詳細に説明する。
【００１２】
（Ｓ１）インバータが系統に注入する高調波電流を０にして系統連系点の電圧とインバータの入出力電流を測定する。
【００１３】
（Ｓ２）上記の測定による電圧と電流をフーリエ変換し、注入予定の高調波電流の次数を含む周波数領域のフーリエ変換係数を求める。
【００１４】
（Ｓ３）上記の係数を系統に存在する正弦波及び余弦波の外乱成分として記録しておく。
【００１５】
以上までの手順により、系統に存在する外乱成分を各次数別に測定・記録しておく。
【００１６】
（Ｓ４）インバータから系統に高調波電流を注入し、このときの連系点の電圧とインバータ電流を測定する。この測定処理は、従来と同様になる。
【００１７】
（Ｓ５）上記の手順（Ｓ４）により測定された電圧と電流の次数成分毎に、手順（Ｓ１）〜（Ｓ３）で得ておく外乱成分を除去し、この除去した電圧と電流の振幅比Ａｂｓと位相差Ａｒｇを系統特性として求める。
【００１８】
図２〜図４は、本実施形態の測定方法による系統特性の測定結果を示す。これら図と図５〜図７の比較から分かるように、本実施形態ではインバータから系統に注入する高調波電流の振幅を３Ａ、１Ａ、０．５Ａと変化させても、ほぼ同じ測定結果が得られる。
【００１９】
このことは、系統特性の測定のためにインバータから注入する高調波電流を小さくでき、これに伴い系統特性測定時の系統連系点電圧歪みを従来方法に比べて小さくできることになる。
【００２０】
【発明の効果】
以上のとおり、本発明によれば、インバータから注入する高調波電流０での電圧と電流を測定し、この測定から系統に存在する外乱成分を各次数別に求めておき、インバータから高調波電流を注入した測定結果から外乱成分を除去して系統特性を求めるようにしたため、比較的小さな高調波電流を注入しながら系統に存在する高調波電流による影響を無くした正確な系統特性の測定ができる。
【図面の簡単な説明】
【図１】本発明の実施形態を示す測定手順図。
【図２】実施形態における振幅比と位相差の測定結果。
【図３】実施形態における振幅比と位相差の測定結果。
【図４】実施形態における振幅比と位相差の測定結果。
【図５】従来の測定方法による振幅比と位相差の測定結果。
【図６】従来の測定方法による振幅比と位相差の測定結果。
【図７】従来の測定方法による振幅比と位相差の測定結果。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for measuring a system characteristic from a voltage and a current when a harmonic current is injected from a semiconductor power converter into a power system.
[0002]
[Prior art]
To measure system characteristics such as the frequency characteristics of the power system, a semiconductor power converter (inverter) is connected to the power system, harmonic current is injected from the semiconductor power converter into the system, and the voltage at the system interconnection point is measured. There is a method of measuring a current and obtaining an amplitude ratio or a phase difference between the voltage and the current.
[0003]
[Problems to be solved by the invention]
The system voltage is not an ideal sine wave of only the fundamental wave, but includes harmonics. Further, the output current of the inverter includes the exciting current of the interconnection transformer in addition to the current according to the command value.
[0004]
Under these circumstances, the measured voltage and current at the grid interconnection point include harmonic voltages other than the harmonic voltage distortion generated by the injected harmonic current, making it difficult to accurately measure system characteristics. .
[0005]
FIGS. 5 to 7 show the results of measuring the characteristics of the upper system side by changing the harmonic current applied from the inverter to the system in the no-load state to 3 A, 1 A, and 0.5 A, and FIG. The amplitude ratio Abs according to the conventional measurement method is shown, and the phase difference Arg is shown for each harmonic order in (b).
[0006]
As can be seen from these figures, when the harmonic current was changed to 3 A, 1 A, and 0.5 A, the measurement was less accurate at 1 A and 0.5 A than at 3 A.
[0007]
As described above, in the conventional measurement method, a large harmonic current must be injected to accurately measure the system characteristics. Along with this, the voltage distortion at the system interconnection point at the time of measuring the system characteristics also increases.
[0008]
An object of the present invention is to provide a measurement method capable of accurately measuring system characteristics by injection of a relatively low harmonic current.
[0009]
[Means for Solving the Problems]
The present invention measures the voltage and current at the
[0010]
In a method of measuring characteristics of a power system from voltage and current when a harmonic current is injected from a semiconductor power converter into a power system,
The harmonic current injected into the system by the semiconductor power converter is set to 0, and the voltage and current at the system interconnection point are measured.
The Fourier transform coefficients of the measured voltage and current are recorded as disturbance components of sine and cosine waves existing in the power system,
The harmonic current is injected from the semiconductor power converter into the power system, and the voltage and current at the interconnection point at this time are measured.
For each of the order components of the measured voltage and the current, a system characteristic is obtained from an amplitude ratio and a phase difference between the voltage and the current from which the disturbance component has been removed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a measurement processing procedure showing an embodiment of the present invention. Hereinafter, each procedure will be described in detail.
[0012]
(S1) The harmonic current injected into the system by the inverter is set to 0, and the voltage at the system interconnection point and the input / output current of the inverter are measured.
[0013]
(S2) Fourier transform is performed on the voltage and the current obtained by the above measurement, and a Fourier transform coefficient in a frequency domain including the order of the harmonic current to be injected is obtained.
[0014]
(S3) The above coefficients are recorded as disturbance components of sine and cosine waves existing in the system.
[0015]
By the above procedure, the disturbance components existing in the system are measured and recorded for each order.
[0016]
(S4) A harmonic current is injected from the inverter into the system, and the voltage at the interconnection point and the inverter current at this time are measured. This measurement process is the same as the conventional one.
[0017]
(S5) For each of the order components of the voltage and current measured by the above procedure (S4), the disturbance components obtained in the procedures (S1) to (S3) are removed, and the amplitude ratio Abs of the removed voltage and current is removed. And the phase difference Arg are obtained as system characteristics.
[0018]
2 to 4 show measurement results of system characteristics by the measurement method of the present embodiment. As can be seen from the comparison between these figures and FIGS. 5 to 7, in this embodiment, even if the amplitude of the harmonic current injected from the inverter into the system is changed to 3 A, 1 A, and 0.5 A, almost the same measurement results are obtained. Can be
[0019]
This means that the harmonic current injected from the inverter for measuring the system characteristics can be reduced, and accordingly, the voltage distortion at the system interconnection point during the measurement of the system characteristics can be reduced as compared with the conventional method.
[0020]
【The invention's effect】
As described above, according to the present invention, the voltage and current at the
[Brief description of the drawings]
FIG. 1 is a measurement procedure diagram showing an embodiment of the present invention.
FIG. 2 shows a measurement result of an amplitude ratio and a phase difference in the embodiment.
FIG. 3 shows measurement results of an amplitude ratio and a phase difference in the embodiment.
FIG. 4 shows a measurement result of an amplitude ratio and a phase difference in the embodiment.
FIG. 5 shows a measurement result of an amplitude ratio and a phase difference by a conventional measurement method.
FIG. 6 shows a measurement result of an amplitude ratio and a phase difference by a conventional measurement method.
FIG. 7 shows a measurement result of an amplitude ratio and a phase difference by a conventional measurement method.
Claims (1)
半導体電力変換装置が系統に注入する高調波電流を０にして系統連系点の電圧と電流を測定し、
前記測定電圧と電流のフーリエ変換係数を電力系統に存在する正弦波及び余弦波の外乱成分として記録しておき、
半導体電力変換装置から電力系統に高調波電流を注入し、このときの連系点の電圧と電流を測定し、
前記測定電圧と電流の次数成分毎に、前記外乱成分を除去した電圧と電流の振幅比と位相差から系統特性を求めることを特徴とする電力系統特性測定方法。In a method of measuring characteristics of a power system from voltage and current when a harmonic current is injected from a semiconductor power converter into a power system,
The harmonic current injected into the system by the semiconductor power converter is set to 0, and the voltage and current at the system interconnection point are measured.
The Fourier transform coefficients of the measured voltage and current are recorded as disturbance components of sine and cosine waves existing in the power system,
The harmonic current is injected from the semiconductor power converter into the power system, and the voltage and current at the interconnection point at this time are measured.
A power system characteristic measuring method comprising: obtaining system characteristics from an amplitude ratio and a phase difference between a voltage and a current from which the disturbance component has been removed, for each of the order components of the measured voltage and the current.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3448097A JP3598710B2 (en) | 1997-02-19 | 1997-02-19 | Power system characteristic measurement method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3448097A JP3598710B2 (en) | 1997-02-19 | 1997-02-19 | Power system characteristic measurement method |
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| JPH10232255A JPH10232255A (en) | 1998-09-02 |
| JP3598710B2 true JP3598710B2 (en) | 2004-12-08 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103176097A (en) * | 2012-12-12 | 2013-06-26 | 万达集团股份有限公司 | Intelligent electricity larceny preventing wireless alarming method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104749434B (en) * | 2015-03-10 | 2017-07-28 | 清华大学 | Harmonic emission level estimation method based on parameter identification |
| CN108680792B (en) * | 2018-05-28 | 2020-06-05 | 国网内蒙古东部电力有限公司 | Dynamic admittance measuring method for new energy grid-connected system with power electronic device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103176097A (en) * | 2012-12-12 | 2013-06-26 | 万达集团股份有限公司 | Intelligent electricity larceny preventing wireless alarming method |
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| Publication number | Publication date |
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| JPH10232255A (en) | 1998-09-02 |
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