电力系统保护与控制
電力繫統保護與控製
전력계통보호여공제
POWER SYSTM PROTECTION AND CONTROL
2014年
4期
34-39
,共6页
李正明%徐敏%潘天红%陈武晖
李正明%徐敏%潘天紅%陳武暉
리정명%서민%반천홍%진무휘
分布式电源%小波变换%希尔伯特-黄变换%经验模态分解%谐波检测
分佈式電源%小波變換%希爾伯特-黃變換%經驗模態分解%諧波檢測
분포식전원%소파변환%희이백특-황변환%경험모태분해%해파검측
distributed generator%wavelet transform%Hilbert-Huang transform%empirical mode decomposition%harmonic detection
在分布式电源并网系统中,大量逆变装置的使用与非线性负载的接入,给电网带来严重的谐波污染,传统的检测方法(如:快速傅里叶变换、小波分析等)对同步信号检测、基函数选取有较大的依赖性,难以适应微电网环境下的谐波检测要求。为此,结合小波变换与HHT,提出一种新的微电源并网模式下的谐波检测与分析方法。该方法利用小波变换多分辨率分析思想对信号进行划分,并对划分后的信号进行经验模态分解,得到一系列的经验模态函数( intrinsic mode function ,IMF),并从IMF分量中提取出基波分量和高次谐波;再对IMF分量进行Hilbert变换得到信号的频率、幅值信息。仿真实验表明该算法的谐波分析精度高,实时性好,能满足分布式并网系统的谐波检测要求。
在分佈式電源併網繫統中,大量逆變裝置的使用與非線性負載的接入,給電網帶來嚴重的諧波汙染,傳統的檢測方法(如:快速傅裏葉變換、小波分析等)對同步信號檢測、基函數選取有較大的依賴性,難以適應微電網環境下的諧波檢測要求。為此,結閤小波變換與HHT,提齣一種新的微電源併網模式下的諧波檢測與分析方法。該方法利用小波變換多分辨率分析思想對信號進行劃分,併對劃分後的信號進行經驗模態分解,得到一繫列的經驗模態函數( intrinsic mode function ,IMF),併從IMF分量中提取齣基波分量和高次諧波;再對IMF分量進行Hilbert變換得到信號的頻率、幅值信息。倣真實驗錶明該算法的諧波分析精度高,實時性好,能滿足分佈式併網繫統的諧波檢測要求。
재분포식전원병망계통중,대량역변장치적사용여비선성부재적접입,급전망대래엄중적해파오염,전통적검측방법(여:쾌속부리협변환、소파분석등)대동보신호검측、기함수선취유교대적의뢰성,난이괄응미전망배경하적해파검측요구。위차,결합소파변환여HHT,제출일충신적미전원병망모식하적해파검측여분석방법。해방법이용소파변환다분변솔분석사상대신호진행화분,병대화분후적신호진행경험모태분해,득도일계렬적경험모태함수( intrinsic mode function ,IMF),병종IMF분량중제취출기파분량화고차해파;재대IMF분량진행Hilbert변환득도신호적빈솔、폭치신식。방진실험표명해산법적해파분석정도고,실시성호,능만족분포식병망계통적해파검측요구。
In distributed connected grid system, there is serious harmonic pollution caused by wide use of inverter units and access of nonlinear loads. The traditional detection methods such as Fast Fourier Transform and wavelet analysis heavily depend on synchronous signal detection or basis functions selection, and don’t satisfy the requirements of the harmonic detection of micro grid environment. Therefore, a novel harmonic detection and analysis method under the mode of micro-sources connected in parauel is proposed combining the wavelet transform with HHT. The method uses multi resolution analysis of wavelet transform to process the original signal. Then, a series of intrinsic mode function (IMF) components are obtained from the processed signal by using empirical mode decomposition algorithm, and the fundamental component and harmonic are extracted from the IMF components. Finally, the frequency and amplitude of signal are calculated by using the Hilbert transform. Simulation results demonstrate that the proposed algorithm has high precision and good real-time characteristics. Furthermore, the algorithm can satisfy the requirements of the harmonic detection of distributed connected grid system.