Time-alignment of electrical network measurements through time series of cycle RMS values

Abstract

The distributed measurement of voltages and currents throughout an industrial plant is critical and necessary in order to have surges and/or meaningful events happening on different locations properly correlated and analysed. This provides a broad and integrated view of the plant’s electrical network state. In a distributed measurement environment, several meters are used simultaneously and the proper time-alignment is often mandatory. The time-alignment technique proposed in this paper takes advantage of the network’s own voltage signal characteristics. The voltage profiles of every electrical network present unique signature, characterized by the variations on the voltage magnitude provoked by the stochastic switching of different load types, complementing the voltage amplitude fluctuation from the power utility connection. Taking advantage of such dynamic, this work will introduce the rmsSync (RMS time-alignment synchronization technique), capable of providing a time-alignment for measurements taken by different equipment without the need of additional synchronization methods. The technique is based on the classic cross-correlation function applied to time series, which is not applied over the instantaneous signal voltage values, but over the RMS values time series, calculated on a cycle basis. Simulations and experiments show the sturdiness of the proposal, which has great applicability to any measurement system that requires time-alignment method.