Power system frequency estimation in the shortened measurement time

An algorithm for fast measurement and estimation of power system frequency is presented. The frequency is calculated by an interpolation of the amplitude coefficients of the discrete Fourier transform. An analysis is made to study the influence of leakage effect and a number of sampling points when the rectangular window and the Hanning window are used. Algorithms are proposed for two cases: the measurement time is an integer multiple of the fundamental period of the power system, and it is below one period. Interpolations with longer time of measurement and with larger number of points decrease the systematic errors. When the time is shortened below the signal period, the DC coefficients are taken into account. If the sinusoidal signal is sampled at 64 samples per measurement interval, the proposed method achieves accuracy in measuring the frequency under a hundreth of Hz.