基于数学形态滤波和Hilbert-Huang变换的风电场闪变检测

Detection of Flicker Caused by Wind Farm based on Mathematical Morphology Filter and Hilbert-Huang Transformation

随着风电场装机容量不断增加,风力发电所引起的电能质量问题不容忽视,电压波动和闪变尤为严重。对风电场引起的电压波动和闪变进行有效评估和治理,需要以准确检测为前提。针对风电场引起闪变的特性提出一种系统、准确、快速的闪变检测方法,首先采用复合数学形态学滤波器滤除原始闪变信号中的多种噪声,然后采用Hilbert变换提取去噪后闪变包络信号,在此基础上利用适于分析非平稳、非线性信号的Hilbert-Huang变换方法对闪变包络进行时频分析。仿真结果表明:该方法能够准确提取闪变的频率、幅值和时刻信息,对分析风电场引起的闪变具有有效性。

With the increasing in wind farm capacity,effects of wind power generation on power quality of the grid connected become more serious.Voltage fluctuation and flicker are among the most serious ones.To assess and manage voltage fluctuation and flicker,an accurate detection method is necessary.According to characteristics of flicker caused by wind farm,a systematic,accurate and fast flicker detection method is introduced.First,with Mathematical Morphology(MM)filter,noises contained in flicker signal can be filtered out.Then to the filtered flicker curves,a track method based on Hilbert transform is adopted to get flicker's envelope which is the base of attaining relevant parameters of flicker.Finally,the envelope is simultaneously analyzed in both time-domain and frequency-domain by a novel non-stationary signal processing method,the Hilbert-Huang Transform(HHT).Simulation experiments show that with this method,time,frequency and amplitude information of non-stationary flicker signals can be accurately detected and the proposed method is effective in the analysis of flickers caused by wind farm.