光伏并网扰动检测中基于局部模极大值的小波选取

The Research of Wavelet Selection in Detection Transient Interference of Grid-connected Photovoltaic Based on Model Maximum

光伏并网系统中的扰动是一类非线性非平稳突变信号。针对扰动信号的检测问题,探讨了一种基于小波变换局部模极大值的信号检测方法。阐述了扰动检测的基本原理,研究了工程领域已有小波的基本性质。以紧支性、对称性、正则性、消失矩阶数四项特性为基本点,分析了这些性质与信号突变性之间的联系,提出了准确检测瞬态扰动的小波选取一般性准则,即"支集宽、正则性优、消失矩阶数高"准则。根据所提出的准则,有针对性的选择了DB1、DB6、sym6和coif3四种小波进行对比性仿真实验。结果证明了本文所提出准则的正确性与可靠性。

To aim at the transient interference in grid connected photovoltaic system, the signal testirlg based on model maximum theory is discussed. The principle of the technique and the basic properties of existing wavelet in engineering are studied. The connection between these properties and the signal singularity are also analyzed on the grounds of support length, symmetry, regularity, and cancellations of wavelet, and the wavelet selection principles are proposed. On the basic of these principles, the four kinds of wavelets DB1, DB6, sym6 and coil3 are chosen in comparative simulation experiment. The result of simulation indicates that the method is effective and reliable.