局部均值分解在电力系统间谐波和谐波失真信号检测中的应用

Application of local mean decomposition in power quality disturbance detection

将局部均值分解LMD(Local Mean Decomposition)法应用于电能质量扰动检测,选取电力系统中典型间谐波扰动信号、短时谐波信号、暂态谐波信号、时变谐波信号和变压器中的实际多频谐波信号,应用LMD对其进行分析。间谐波信号的仿真结果表明LMD方法在求取的瞬时特征参数波动幅度、端部效果、检测精度和运行时间方面都优于Hilbert-Huang变换(HHT)方法;谐波失真信号的仿真结果表明该方法可以准确检测扰动信号的频率、幅值以及扰动发生与恢复的时刻。对某500 kV变电站35 kV侧投运电容器时引起的35 kV侧B相电压下降和畸变的信号分析结果进一步证明了所提方法的正确性。

LMD（Local Mean Decomposition） is applied in the detection of power quality disturbance. The typical interharmonic interference signal,short-time harmonic signal,transient harmonic signal,time-varying harmonic signal,as well as the actual multi-frequency harmonic signals occurred in transformers,are selected and analyzed by LMD. Results of interharmonic signal simulation show that,the LMD method is better than the HHT method in the parameter fluctuation of transient characteristic parameter detection ,the end effect, the detection accuracy and the running time. Results of harmonic distortion signal simulation show that,the frequency,amplitude,occurrence and recovery time of disturbance signal can be accurately detected by LMD. The sag and distortion of 35 kV-side phase-B voltage caused by the switch-in of a 35 kV-side capacitor in a 500 kV substation are analyzed,proving the correctness of the proposed method.