PEI Liang(裴亮)1, LI Jing(李晶)2, CAO Mao-yong(曹茂永)2, LIU Shi-xuan(刘世萱)1
(1. Shandong Provincial Key Laboratory of Ocean Environment Monitoring Technology, Institute of Oceannographic Instrumentation, Shandong Academy of Sciences, Qingdao 266001, China; 2. College of Information and Electrical Engineering, Shandong University of Science and Technology, Qingdao 266510, China)
Abstract：To avoid drawbacks of classic discrete Fourier transform (DFT) method, modern spectral estimation theory was introduced into harmonics and inter-harmonics analysis in electric power system. Idea of the subspace-based root-min-norm algorithm was described, but it is susceptive to noises with unstable performance in different SNRs. So the modified root-min-norm algorithm based on cross-spectral estimation was proposed, utilizing cross-correlation matrix and independence of different Gaussian noise series. Lots of simulation experiments were carried out to test performance of the algorithm in different conditions, and its statistical characteristics was presented. Simulation results show that the modified algorithm can efficiently suppress influence of the noises, and has high frequency resolution, high precision and high stability, and it is much superior to the classic DFT method.
Key words：electric power system； inter-harmonics； cross-spectral estimation； singular value decomposition（SVD）； subspace decomposition； min-norm algorithm
CLD number： TM744 Document code： A
Article ID： 1674-8042(2012)01-0066-04 doi： 10.3969/j.issn.1674-8042.2012.01.014
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