An improved frequency estimation algorithm based on DFT and iterative method

In this paper, a new frequency estimation algorithm based on the DFT (Discrete Fourier Transform) is proposed to increase the estimation accuracy. The proposed algorithm consists of three stages such as DFT, frequency estimation and error compensation, and iterative loop. First, the input voltage signal is decomposed into two components by using DFT. Secondly, the two components, the real part and the imaginary part, and their derivatives are combined to estimate the frequency. Finally, to obtain a better estimated frequency, an iterative method is applied. To evaluate the performance of the proposed algorithm, frequency change is considered when the test signals are generated. The performance of the proposed method was also evaluated for a dynamic condition in a 5-bus model system. PSCAD/EMTDC was used to generate the voltage signal for a load increase case. The performance evaluation results show that the proposed algorithm can accurately estimate the power system frequency in the presence of the amplitude variation and the frequency change.