基于两个实值小波变换定量检测电能质量扰动的新方法

文章针对电压中断、电压下跌和电压上升这三种电压波形畸变进行了定量检测研究。提出了基于两个实值小波变换的修正幅值的新概念，并从理论上说明了该修正幅值具有如下的特性：(1)在非故障区间内取值均相等，且恰好等于额定电压的幅值；(2)在故障区间内(端点除外)取值也相同，且恰好等于故障区间内的电压的幅值；(3)与电压波形畸变所在相位、长度及电压的工频频率无关。文章还应用该修正幅值对这三种电压波形畸变进行了检测，检测图能定位故障发生、终止时刻和区分电能质量扰动的类型，并可定量测定出电压幅值上升或下降的幅度。

A NEW METHOD TO QUANTITATIVELY DETECT POWER QUALITY DISTURBANCES BASED ON TWO REAL WAVELET TRANSFORMS

The quantitative detection of three distortions of voltage waveform, i.e., the voltage interruption, voltage sag and voltage swell, is conducted and on this basis a new concept of amplitude-adjustment based on two real wavelet transform is presented. Theoretically the presented amplitude-adjustment possesses following features, they are: (1)The values of amplitude-adjustments acquired in the non-failure interval are same and equal to the amplitude of the nominal voltage; (2) The values of amplitude-adjustments acquired in the failure interval (except the terminals) are also same and equal to the amplitude of the voltage within the failure interval; (3) The value of amplitude-adjustment does not depend on the position where the failure interval locates, the length of the failure interval and the fundamental frequency of the voltage. The distorted waveforms of the voltage caused by voltage interruption, voltage sag and voltage swell are detected by the amplitude-adjustment. With the detected graphs the points of time where the fault began and terminated can be determined and the types of power quality disturbances can be distinguished, besides, the magnitude of voltage arising or descent caused by voltage sag or swell can also be quantitatively measured.