CEEMD在电能质量扰动检测中的应用

Application of CEEMD in power quality disturbance detection

为了解决总体平均经验模态分解(EEMD)处理非平稳、非线性信号的不足,提出了一种基于完全经验模态分解(CEEMD)的电能质量扰动检测新方法。首先采用CEEMD对含噪的电能质量扰动信号进行分解得到固有模态函数,并对固有模态函数进行Hilbert变换检测出瞬时幅值和瞬时相位特征参数。对所得瞬时幅值求取二阶导数得到模极大值点,提高了通过模极大值点定位扰动时刻的准确性。针对高频复合扰动采取两次CEEMD分解方法去除噪声与虚假分量有效提取出扰动成分,针对稳态扰动提出先去除谐波再提取闪变包络的检测方法。并通过Matlab仿真实验以及依托交流调压器负载实验和三电平实验平台的实测数据,验证了该方法既可以对未知扰动信号进行辨识区分,也可以确定电能质量扰动的时刻、类型、频率和幅值等特征参数。

To solve the problem that Ensemble Empirical Mode Decomposition（EEMD） is not insufficient in processing the non-linear and non-stationary signal. On this basis, this paper presents a new method of power quality disturbance detection based on Complete Ensemble Empirical Mode Decomposition（CEEMD）. Firstly, the power quality disturbance signal with noise is decomposed into Intrinsic Mode Function（IMF） by CEEMD, whose instantaneous amplitude and phase characteristic are detected by Hilbert Transform. Furthermore, the obtained instantaneous amplitude is derived to get its modulus maximum points by second-order derivative, which improves the accuracy of positioning disturbance time. Given the high frequency compound disturbance, the CEEMD decomposition method is adopted twice to remove noise and false components. According to steady state disturbance, the detection method is to remove harmonic components firstly and then to extract the flicker envelope. At last, through Matlab simulation experiments and the data measured on AC voltage regulator load experiment and three-level experimental platform verify that this method is able to identify the unknown disturbance signal, and as well as determine the power quality disturbance time, type, frequency, amplitude and other characteristic parameters.