基于改进形态滤波器和弧长差分序列的微电网电能质量扰动定位与识别

Location and Identification of Micro-Grid Power Quality Disturbances Based on Modified Morphological Filter and Arc Length Differential Sequence

针对强噪声背景下微电网电能信号扰动定位和识别困难的问题,提出一种基于改进形态滤波器和弧长差分序列的扰动定位与识别方法。首先,将交替混合形态滤波器中的膨胀和腐蚀函数改进为均值膨胀和均值腐蚀函数,再对电能扰动信号进行滤波。然后,在分析扰动波形变化规律和三个典型扰动算例的基础上,定义并计算滤波后扰动信号的弧长差分序列。最后,利用弧长差分序列定位准确扰动时间,从弧长差分序列和滤波后信号中提取幅值特征和波峰特征,输入到已定义识别规则的扰动识别器,实现扰动识别。仿真试验和实际微电网数据试验结果表明,该方法能够精确定位和识别混入不同强度噪声的5种单一扰动和3种复合扰动,适用于实际微电网电能信号扰动的定位与识别。

Aiming at the problem of location and identification of micro-grid power quality disturbances with strong noise,a novel method based on modified morphological filter and arc length difference sequence is proposed to locate and identify disturbances.Firstly,the dilation function and the erosion function are separately improved to the mean-dilation function and the mean-erosion function,and the improved alternating hybrid morphological filter is used to filter the power quality signal.Then,on the basis of the analysis of the disturbance waveform and the three typical disturbance examples,the arc length differential sequence of the filtered signal is defined and calculated.Finally,based on the arc length difference sequence,disturbance time is accurately located,the amplitude and peaks characteristics are extracted from the arc length difference sequence and filtered signal.These characteristics are input to the identifier defined by the disturbance identification rules to get the final identification results.The simulation and one practical micro-grid data test shown that the proposed method could accurately locate and identify 5 types of single disturbances and 3 types of complex disturbances mixed with different intensity of noise,and is suitable for the disturbances location and identification of actual micro-grid power quality.