Non-recursive Discrete Fourier Transform-Based Frequency Estimation of the Power System

This paper suggests a frequency estimation method which consists of a combination of a revised 3-Level discrete Fourier transform (DFT) and a second derivative of each orthogonal component. The revised 3-Level DFT aims to counteract the harmful effect of harmonics and noises on frequency estimation accuracy by applying DFT to the input signal three times consecutively. Also, a cancelation technique of a tracking delay which is directly related to the data window length is proposed by adjusting the angle of voltage phasor. To evaluate the performance of proposed method, three different kinds of computer-generated-signals which are according to IEEE C37.118.1a 2014 PMU Standard requirements are considered. In addition, signals which are collected at the transmission system modeled by electro magnetic transient program (EMTP-RV) under the dynamic condition and the single line-to-ground fault are also used. The simulation results indicate that the proposed method can track the frequency of the signal accurately.