795 / 2019-04-29 11:16:57

An Improved Frequency Estimation Method Without Iteration

frequency estimation, frequency measurement, frequency tracking, frequency protection, discrete Fourier transformer.

The conventional frequency estimation solutions based on the Discrete Fourier Transformer (DFT) cannot provide both the fast response and the good reliability under the system disturbance. In this paper, an improved frequency estimation solution is presented. Based on the angle characteristic of the positive sequence voltage, this solution exactly calculates the frequency deviation from angle difference of the continuous power cycles, without any iteration. Hanning window is applied to reduce the harmonics’ interfaces when the frequency deviation is large. Moreover, the angle step-change detection based on the abnormal rate of change of frequency (ROCOF) is also applied to improve the reliability of the solution. The simulation results show the frequency estimation performances are well improved.