  We consider the problem of PMU-based state estimation combining information
coming from ubiquitous power demand time series and only a limited number of
PMUs. Conversely to recent literature in which synchrophasor devices are often
assumed perfectly synchronized with the Coordinated Universal Time (UTC), we
explicitly consider the presence of time-synchronization errors in the
measurements due to different non-ideal causes such as imperfect satellite
localization and internal clock inaccuracy. We propose a recursive Kalman-based
algorithm which allows for the explicit offline computation of the expected
performance and for the real-time compensation of possible frequency mismatches
among different PMUs. Based on the IEEE C37.118.1 standard on PMUs, we test the
proposed solution and compare it with alternative approaches on both synthetic
data from the IEEE 123 node standard distribution feeder and real-field data
from a small medium voltage distribution feeder located inside the EPFL campus
in Lausanne.
