A-Posteriori Synchronization of Power Quality Data in Smart Grids

This paper is concerned with synchronizing smart meter data in post-processing. A-posteriori synchronization is necessary in cases where real time online synchronization failed or was unavailable. In the paper, a simple method to synchronize power quality data series from multiple meters is proposed. The method analyses similarities in voltage data and estimates the lags between the meters. In order to obtain a single data series representing the most relevant phenomena that happen at the location of the smart meter, Singular Value Decomposition is used. It helps to decrease the dimensionality of the smart meter data to one. To synchronize the time of two or more metering devices the correlation between data series were calculated. Distance between zero and the maximum absolute peak of the cross-correlation is taken as a lag. For signals containing transients and dips, accuracy may be increased by correlating the first order difference of the signals. The output of the proposed algorithm is the value of signals' time lags. The accuracy of the algorithm is limited by the aggregation level of data under examination.