A sample-autocorrelation-based approach for monitoring power-system damping from ambient synchrophasor data

Estimation of power-system damping from synchrophasor frequency measurements is studied. Specifically, a procedure for determining the damping of a dominant mode from the turns ratio of the sample autocorrelation function is outlined. The main contribution of the work is to then develop performance bounds on the damping estimates, and demonstrate approximation of these bounds entirely from the measurement data. The technique has been applied to archived historical data from the Western Electricity Coordinating Council (WECC), and a real-time implementation has also been developed.