Wide-range, fast and robust estimation of power system frequency

摘要

A novel method of frequency estimation, for power system applications such as control and protection, is proposed and its performance is evaluated. The proposed frequency estimator can measure small as well as large deviations from the nominal point. It closely follows step, ramp and oscillatory variations of the frequency over time. Other significant features of the proposed algorithm are: (a) structural simplicity, which renders it suitable for hardware/software implementation; (b) performance robustness in the presence of DC offset and harmonic components; (c) noise immunity; (d) performance robustness with respect to external disturbances such as commutation notches and switching transients; and (e) flexibility of control over speed and accuracy. Rate of change of frequency is also directly provided by the estimator which is a requirement in some system protection algorithms. In a highly polluted environment, the proposed estimator can be set to measure the frequency in few cycles of the signal and with a steady-state error which is limited to 0.02 Hz.