The impact of exponentially decaying direct component on the Fourier algorithm is theoretically investigated first in this paper. A new algorithm to eliminate the error caused by this decaying component in the Fourier...
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The impact of exponentially decaying direct component on the Fourier algorithm is theoretically investigated first in this paper. A new algorithm to eliminate the error caused by this decaying component in the Fourier algorithm has been proposed. Furthermore, three simplified methods are proposed to alleviate the computation burden. The performance of the Fourier algorithm improved with these methods along with the least error squares algorithm is evaluated using a simple network and a real power system modeled by EMTP. The evaluation results are presented and discussed.
Phasor estimation algorithms for protective relaying are required to filter out unwanted components from the input signals and retain only the components of interest. The components to be removed include harmonics and...
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Phasor estimation algorithms for protective relaying are required to filter out unwanted components from the input signals and retain only the components of interest. The components to be removed include harmonics and the decaying-exponential transient (dc offset) component. They affect the accuracy and the speed of convergence of the phasor estimation algorithms to a great extent. This paper presents a new technique, which effectively removes the harmonics and the decaying dc component present in the input signals, within half a cycle of the power system frequency. This is achieved by means of a simple computational procedure using three off-line look-up tables. The proposed algorithm has been tested for a wide variety of signals to assess its performance. The performance is also compared with the two most popular half-cycle phasor estimation algorithms;the half-cycle least error squares algorithms and the mimic plus half-cycle Fourier algorithm. The test results show that the proposed relaying algorithm has a faster convergence and better accuracy compared to these previously proposed algorithms. The results also indicate that the proposed algorithm converges to its final value within half a cycle of the power system frequency as compared to the other two algorithms, which take more than half a cycle to converge, when a decaying dc component is present in the input.
This paper presents a new approach to detect and measure voltage disturbances based on the compound operation of wavelet transform (WT), leasterrorsquares (LES) algorithm and Kalman filter. The function of WT is to ...
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ISBN:
(纸本)9781424446483
This paper presents a new approach to detect and measure voltage disturbances based on the compound operation of wavelet transform (WT), leasterrorsquares (LES) algorithm and Kalman filter. The function of WT is to detect occurrence and duration of disturbances. The estimation of the phasors of the three-phase voltages is performed through the application of a LES algorithm. The Kalman filter works in conjunction with the LES output as a flicker meter. The performance of the proposed method is evaluated through extensive numerical simulations, simulations in MATLAB/Simulink and real-time implementation. Selected results presented in the paper confirm the accuracy and correct performance of the proposed method.
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