Abstract
We propose a new decaying dc component estimation algorithm for digital relaying. Fault currents tend to include a dc decaying component. This component decreases the accuracy and speed of the protection relay operation. The proposed algorithm can estimate and eliminate the dc decaying component from fault current signals after one cycle from the fault instant. Also, it can be applied to a conventional discrete Fourier transform to calculate phasor quantities of fault currents in a digital protection relay. In the proposed algorithm, the dc decaying magnitude and time constant are estimated exactly by integrating fault currents during one cycle. The dc decaying component is eliminated by subtracting the dc value at each sampling instant. To verify the performance of the proposed algorithm, we performed a dc component estimation test and distance protection test using PSCAD/EMTDC. The results of the PSCAD/EMTDC simulation showed that the proposed algorithm can estimate dc components exactly from fault currents and can be applied to digital protection relays for phasor extraction.
Original language | English |
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Pages (from-to) | 73-78 |
Number of pages | 6 |
Journal | IEEE Transactions on Power Delivery |
Volume | 24 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2009 |
Bibliographical note
Funding Information:Manuscript received August 07, 2007; revised January 02, 2008. Current version published December 24, 2008. This work is the result of the KETEP fostering program and the KESRI Project (R-2007-2-055) funded by the Korean government (MKE). Paper no. TPWRD-00478-2007. Y. S. Cho and C. K. Lee are with the Electrotechnology R&D Center, LS Industrial Systems Co., Cheongju 361-720, Korea (e-mail: [email protected], [email protected]). G. Jang is with the School of Electrical Engineering, Korea University, Seoul 136-701, Korea (e-mail: [email protected]). H. J. Lee is with the Department of Electrical Engineering, Kwangwoon University, Seoul 139-701, Korea (e-mail: [email protected]). Digital Object Identifier 10.1109/TPWRD.2008.2005682
Keywords
- DC estimation
- DC magnitude
- DC time constant
- Digital protection
- Discrete Fourier transform (DFT)
- Fault current
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering