Real-Time Estimation of Power System Frequency Using a Three-Level Discrete Fourier Transform Method
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...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2014-12-01
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| Series: | Energies |
| Subjects: | |
| Online Access: | http://www.mdpi.com/1996-1073/8/1/79 |
| Summary: | 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. |
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| ISSN: | 1996-1073 |