Real-Time Estimation of Power System Frequency Using a Three-Level Discrete Fourier Transform Method

Energies

Soon-Ryul Nam¹  Seung-Hwa Kang²  Sang-Hee Kang² 

[1] Department of Electrical Engineering, Myongji University, Yongin 449-728, Korea;

关键词: amplitude ratio;    power system frequency;    hardware implementation;    real-time estimation;    three-level discrete Fourier transform;    zero-crossing problem;   

DOI  :  10.3390/en8010079

来源: mdpi

【 摘 要 】

This paper proposes a three-level discrete Fourier transform (DFT) method to provide an accurate estimate of power system frequency in real time. The first level decomposes a power system signal into two orthogonal cosine- and sine-filtered signals. The second and third levels are used to determine the amplitude ratio of the cosine- and sine-filtered signals without encountering the zero-crossing problem and with an increase in ability to suppress harmonics and inter-harmonics. The performance of the three-level DFT method is evaluated using computer-simulated signals with harmonics and inter-harmonics. The three-level DFT method is also implemented on a digital signal processor (DSP)-based hardware prototype, and its performance in the hardware implementation is evaluated using a real-time digital simulator (RTDS). The evaluation results show that the three-level DFT method can achieve real-time estimation of power system frequency with satisfactory performance.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.