A novel technique to eliminate the effect of decaying DC component on DFT based phasor estimation

Elrefaie, H.B.; Megahed, A.I.

doi:10.1109/pes.2010.5589342

Cited by 16 publications

(6 citation statements)

References 9 publications

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“…DFT-based techniques are generally used for removal decaying DC offset from phasor estimation [35][36][37][38][39][40]. On the other hand, the decaying DC component affects the accuracy of the DFT algorithm greatly [41][42][43]. Different windows have been suggested and half-cycle DFT was used to get the phasor [10,[43][44][45] in the case of decaying DC offsets.…”

Section: Simulation Results and Data Analysismentioning

confidence: 99%

Frequency estimation and tracking by two-layered iterative DFT with re-sampling in non-steady states of power system

2019

J Wireless Com Network

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Frequency deviation off the nominal one is incurred by sudden changes of frequency and could introduce harmonics and inter-harmonics in the power system, which influences the accuracy of frequency estimation with method of discrete Fourier transform (DFT). A two-layered iterative DFT (TLI-DFT) with re-sampling was presented to measure the frequency in non-steady states. A simple frequency estimation method named exponential sampling is amended to calculate the initial sampling frequency in the inner-layered process of the DFT iteration. In reality, frequencies of two consecutive cycles are always interrelated with each other, so an idea of frequency tracking by outer-layered DFT between cycles is adopted. TLI-DFT can track the frequency in non-steady state in different scenarios, e.g., sudden and random frequency change, signal modulated by a cosine signal, and contaminated by decaying direct current offsets. Mean squared error of measured frequency, rate of change of frequency, and total vector error at different transient conditions indicate that the proposed algorithm is valid and more accurate than the traditional one in the non-steady states of a power system.

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Section: Simulation Results and Data Analysismentioning

confidence: 99%

Frequency estimation and tracking by two-layered iterative DFT with re-sampling in non-steady states of power system

2019

J Wireless Com Network

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“…When, a fault or a disturbance occurs, the current signal consists of exponentially decaying DC offsets in electrical power system (ElRefaie and Megahed, 2010;Benmouyal, 1995;Kezunovic et al, 1992;Sidhu et al, 2003). The decaying rates depend on the time constants determined by the inductive reactance to resistance ratio (X/R ratio) of the system (Diniz de Oliveira et al, 2012;Balamourougan and Sidhu, 2006;Belega and Petri, 2011).…”

Section: Methodsmentioning

confidence: 99%

A Method of Least Squares Error with Iterative Resampling for Frequency Tracking in Smart Grid

Li¹,

Cao²,

Yuan³

2015

J. of Applied Sciences

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A B S T R A C T Phase angle and amplitude of a phasor can be provided by method of Least Squares Error (LSE). The LSE adopted iteratively is able to track the frequency and amplitude of power system in steady states and in kinds of non-steady ones. Iterative LSE with resampling is analyzed in conditions of off-nominal input, nominal input with harmonics and decaying Direct Current (DC) offset and additive Gaussian white noise. In the circumstances of frequency and phase step changes, performance of resampling LSE is compared with traditional LSE. Resampling LSE has better performance than the traditional one in frequency tracking ability and can provide less mean square error.

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“…To enhance robustness and improve accuracy, methods presented in [6,26,27] employ a time window of two fundamental frequency cycles to obtain accurate phasor estimation performance, which meets the requirement of frequency domain methods when the length of data window is adequate. However, in recent years, with the continuous development of power industry, high speed line protections are broadly applied to extra-high-voltage (EHV) and ultra-high-voltage (UHV) transmission lines [28,29].…”

Section: Introductionmentioning

confidence: 99%

A robust and accurate discrete Fourier transform‐based phasor estimation method for frequency domain fault location of power transmission lines

Liang

Zhang

et al. 2022

IET Generation Trans & Dist

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Frequency domain methods had been commonly used in power transmission line fault location. To improve the accuracy of frequency domain fault location methods, this paper studies a robust and accurate discrete Fourier transform (DFT)‐based phasor estimation method. First, this paper analyses the deviation characteristics of DFT output phasors caused by decaying DC components with data window sliding. Based on these characteristics, this paper employs rotation factor computation to construct linear equations for the purpose of estimating the accurate fundamental frequency phasor during fault transient process. In this way, the accurate fundamental frequency phasor can be calculated by a two‐step linear operation. Furthermore, to eliminate the effect of off‐nominal frequency, the proposed method adjusts frequency deviation by using interpolation method. To further enhance the robustness for frequency domain fault location, the PauTa criterion is used to exclude the anomalous equations in the phasor estimation process. Finally, electro‐magnetic fault simulation is used to evaluate the proposed method. The test results demonstrate that the proposed method improve the accuracy of fault location during the fault transient process.

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A novel technique to eliminate the effect of decaying DC component on DFT based phasor estimation

Cited by 16 publications

References 9 publications

Frequency estimation and tracking by two-layered iterative DFT with re-sampling in non-steady states of power system

Frequency estimation and tracking by two-layered iterative DFT with re-sampling in non-steady states of power system

A Method of Least Squares Error with Iterative Resampling for Frequency Tracking in Smart Grid

A robust and accurate discrete Fourier transform‐based phasor estimation method for frequency domain fault location of power transmission lines

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