Accurate and fast frequency tracking for power system signals

The measurement of fundamental frequency is an essential topic for power system control and protection applications. This paper presents a combined approach for accurate and fast tracking of power system frequency on the basis of a zero-crossing algorithm and a three-point algorithm. The accuracy of the classical zero-crossing algorithm is improved by using cubic interpolation with simplified solution. The three- point algorithm is used as an auxiliary method to improve the tracking speed by computing the frequency with only a few sample values. The proposed method is simple, accurate and robust for non-stationary signals and contaminated signals. The performance is demonstrated by simulation results.