Power quality measuring data compression based on new distance measurement

Based on periodic similarity of power quality measuring signals such as voltage, compressed power quality data have low distortion, by recording neighboring cycle with differences in measuring signals and not recording with indifferences. In this paper, on the basis of characteristics of power quality standard signal and disturbing signal, two characteristic quantities, global measurement factor and local measurement factor reflecting power quality signal differences, is proposed to construct a new distance measurement function. Then, the method to determine the measurement threshold is also studied. The test results using measured data show that proposed method distinguish differences of measuring data and compress data availably. And its calculation amount is much less than using wavelet transform or other methods.