基于双小波的短时电压波动信号检测

DETECTION OF SHORT DURATION VOLTAGE VARIATION SIGNAL BASED ON DOUBLE WAVELET

提出了一种基于 db1 小波和 db10 小波检测短时电压波动(Short Duration Voltage Variation,SDVV)信号的方法,首先利用 db1 小波对信号进行分解得到低频系数模,据此初步确定 SDVV 信号的发生时段,并记下每时段的起始和结束时刻点。再应用 db10 小波对信号进行分解得到第一层高频分解系数,而由 db1 小波确定的起始和终止时刻点前后的1/2 采样周期内检测第一层高频分解系数的模极大值,以确定非过零点和波峰的起止点。根据具体的判断规则即可确定电压波动的准确起止时刻,还可根据 db1 小波分解得到的低频系数模确定电压波动的幅度。仿真和试验结果表明了该方法的可行性和有效性。

A method based on dbl and db10 wavelet to detect short duration voltage variation (SDVV) signal was proposed. At first the signal was decomposed by dbl wavelet and low frequency coefficient modules of the decomposed signal were obtained, on this basis probable time intervals of any SDVV events could be determined and the beginning and end points of each time interval were recorded simultaneously. Then the signal was decomposed by db10 wavelet to obtain the first layer high-frequency decomposition coefficients, and within half sampling periods before and after the beginning and end points of each time interval determined by dbl wavelet the module maximum value of first layer high-frequency decomposition coefficients was detected to determine the non-zero-cross points and the beginning and end points of the wave crest. According to the concrete assessment rule the accurate beginning and end moment of voltage variation would be determined, in addition the amplitude of the voltage variation would be determined by above-mentioned low frequency coefficient module. The results from tests and simulation show that the proposed method is feasible and effective.