基于自适应阈值调整小波去噪法和HT-LMD的电流幅值时滞检测方法

Current amplitude delay detection method based on adaptive threshold adjusted wavelet denoising method and HT-LMD

为解决电流幅值时滞效果,避免电流幅值时滞问题对电网运行的质量扰动,保障电网安全可靠运行的问题,基于自适应阈值调整小波去噪法和HT-LMD提出电流幅值时滞检测方法,采用自适应阈值调整小波去噪法去除电流幅值信号中的噪声,根据正交性判据的迭代终止条件,采用HT-LMD分解去噪后的电流幅值信号获取PF分量,通过比较分析PF分量幅值特征、边际谱特征、瞬时频率特征和Hilbert-Huang谱特征,实现电流幅值时滞检测。开展电流幅值时滞检测方法仿真验证,仿真及实验结果表明:随噪声强度变化,该文方法能自适应地更新相关参数,更好地向最优值逼近;除噪效果较为显著,可很好地保存有效信号特征;能有效获取电压暂降LMD分量,具有较好的电流幅值时滞检测效果。

To solve the current amplitude time lag effect,avoid current amplitude disturbance,time delay problem in the quality of power grid operation guarantee safe and reliable operation of the power grid,based on adaptive wavelet denoising threshold adjustment method and HT-LMD,time delay current amplitude detection method is put forward,using adaptive threshold adjusting wavelet denoising method to eliminate the noise in the signal current amplitude.According to the termination condition of the orthogonality criterion,the current amplitude signal after denoising was decomposed by HT-LMD to obtain the PF component.By comparing and analyzing the PF component's amplitude characteristic,marginal spectrum characteristic,instantaneous frequency characteristic and Hilbert-Huang spectrum characteristic,the current amplitude delay detection was realized.The simulation and experimental results show that the proposed method can update the relevant parameters adaptively and approach the optimal value better with the change of noise intensity.The denoising effect is obvious,and the effective signal features can be well preserved.The voltage sag LMD component can be obtained effectively,and the current amplitude delay detection effect is good.