电力系统自动化
電力繫統自動化
전력계통자동화
AUTOMATION OF ELECTRIC POWER SYSTEMS
2012年
2期
70-76
,共7页
IEC标准框架%集合%谐波/间谐波检测%Hanning窗函数%能量损失修正系数%测量环境%最优衡量指标%离散傅里叶变换
IEC標準框架%集閤%諧波/間諧波檢測%Hanning窗函數%能量損失脩正繫數%測量環境%最優衡量指標%離散傅裏葉變換
IEC표준광가%집합%해파/간해파검측%Hanning창함수%능량손실수정계수%측량배경%최우형량지표%리산부리협변환
IEC standard framework group%harmonic / interharmonic detection%Hanning window function%energy-loss correction factor%measurement condition%' optimal measurement index%discrete Fourier transform (DFT)
首先根据Parseval能量积分公式,推导了离散信号经离散傅里叶变换(DFT)后时频域能量的表达公式,并且分析指出,将Hanning窗函数应用于国际电工委员会(IEC)标准框架下的集合概念,其前提条件是保证加窗前的时域能量与加窗(并DFT)后的频域能量相等,同时提出引入“能量损失修正系数”来达到该条件。而后,利用能量损失修正系数,得出了加Hanning窗时集合概念的表达公式,该公式与IEC标准框架下的集合概念完全兼容。接着,对IEC推荐的谐波和间谐波检测方法进行了扩展,扩展方法将谐波和间谐波的检测细化为4种测量环境和5个衡量指标。最后,详细分析了每种测量环境下影响测量精度的因素,并且多方位比较与该测量环境相对应的5个衡量指标的综合性能,从5个指标中选出性能最优的一个作为该测量环境下的最优衡量指标。在实际测量时,根据具体的测量环境,选择对应的最优衡量指标,可以得到最精确的测量结果。
首先根據Parseval能量積分公式,推導瞭離散信號經離散傅裏葉變換(DFT)後時頻域能量的錶達公式,併且分析指齣,將Hanning窗函數應用于國際電工委員會(IEC)標準框架下的集閤概唸,其前提條件是保證加窗前的時域能量與加窗(併DFT)後的頻域能量相等,同時提齣引入“能量損失脩正繫數”來達到該條件。而後,利用能量損失脩正繫數,得齣瞭加Hanning窗時集閤概唸的錶達公式,該公式與IEC標準框架下的集閤概唸完全兼容。接著,對IEC推薦的諧波和間諧波檢測方法進行瞭擴展,擴展方法將諧波和間諧波的檢測細化為4種測量環境和5箇衡量指標。最後,詳細分析瞭每種測量環境下影響測量精度的因素,併且多方位比較與該測量環境相對應的5箇衡量指標的綜閤性能,從5箇指標中選齣性能最優的一箇作為該測量環境下的最優衡量指標。在實際測量時,根據具體的測量環境,選擇對應的最優衡量指標,可以得到最精確的測量結果。
수선근거Parseval능량적분공식,추도료리산신호경리산부리협변환(DFT)후시빈역능량적표체공식,병차분석지출,장Hanning창함수응용우국제전공위원회(IEC)표준광가하적집합개념,기전제조건시보증가창전적시역능량여가창(병DFT)후적빈역능량상등,동시제출인입“능량손실수정계수”래체도해조건。이후,이용능량손실수정계수,득출료가Hanning창시집합개념적표체공식,해공식여IEC표준광가하적집합개념완전겸용。접착,대IEC추천적해파화간해파검측방법진행료확전,확전방법장해파화간해파적검측세화위4충측량배경화5개형량지표。최후,상세분석료매충측량배경하영향측량정도적인소,병차다방위비교여해측량배경상대응적5개형량지표적종합성능,종5개지표중선출성능최우적일개작위해측량배경하적최우형량지표。재실제측량시,근거구체적측량배경,선택대응적최우형량지표,가이득도최정학적측량결과。
According to Parseval' s relation, the formulas which accurately represent the signal energy expressed in the time domain and frequency domain are acquired under the circumstances that the sampled signal is processed by discrete Fourier transform (DFT). In order to make the Hanning window compatible with the group concept recommended by International Eleetrotechnical Commission (IEC) standard, the prerequisite that the energy sum contributed by all spectral lines in the frequency domain must be equivalent to the energy of the sampled signal within the window has to be reached, and an "energy- loss correction factor" is proposed to achieve the prerequisite. By use of the energy-loss correction factor, an expression of the group concept related to Hanning window is obtained and completely compatible with the IEC technique. The method recommended by IEC to measure harmonics and interharmonies is extended, which can be completely expressed by using four measurement conditions and five measurement indices. For each measurement condition, the factors that may affect the measuring accuracy are carefully analyzed, and the measurement index which has the best overall performance in certain measurement condition is selected as the specific optimal measurement index. The most accurate results can be obtained in practical measurement through the application of the specific optimal measurement index.