Phasor, frequency and ROCOF measurements in microgrids: A practical approach

This paper discusses the phasor, frequency, and the rate of change of frequency (ROCOF) estimations in Microgrids. This is accomplished using the estimates processed by a real PMU and their comparisons with the digital Cosine filter, adding new metrics for frequency and ROCOF. A real event recorded is employed aiming to estimate the phasor parameters in time-domain signals. A traditional static phasor model algorithm for the digital Cosine filter is taken into account, using a rectangular window lasting two cycles. Both frequency and ROCOF metrics are conceived by drawing an analogy with their estimations if a dynamic phasor model is assumed. The attained results demonstrate that the digital filtering process done by the Cosine filter outperforms the provided estimates by the real PMU and the new metrics suitably track the changes in frequency and ROCOF.