Distribution-level synchrophasors estimation

Abstract

Various time domain, frequency domain and timefrequency domain methods have been used in literature for the accurate phasor estimation in transmission-level PMUs. This paper assesses the suitability of three such methods, viz., Taylor Weighted Least Square (TWLS), Interpolated Discrete Fourier Transform (IpDFT) and Empirical Wavelet Transform (EWT), for developing the distribution-level PMU under steady state and dynamic conditions, as per the IEEE C37.118.1a-2014. The analysis is considered for fast phasor estimation by considering one cycle observation window. The Total Vector Error (TVE) and response time are chosen as performance metric. It is shown that time-domain and frequency-domain methods, although have less estimation error in case of fundamental phasor estimation and comply with PMU Std. IEEE C37.118.1a-2014, except low order harmonics and out of band interference case. However, in order to estimate the harmonics along with the fundamental phasors, time-frequency based method should be the preferred choice for implementing the D-PMUs. The additional advantage of EWT is to localize the dynamics of the signal in time-frequency plane.