Browse > Article

Modified-Current-Differential Relay for Transformer Protection  

Kang Yong-Cheol (Division of Electronics and Information Engineering, Chonbuk National University)
Jin En-Shu (Division of Electronics and Information Engineering, Chonbuk National University)
Won Sung-Ho (Division of Electronics and Information Engineering, Chonbuk National University)
Publication Information
KIEE International Transactions on Power Engineering / v.5A, no.1, 2005 , pp. 1-8 More about this Journal
Abstract
During magnetic inrush or over-excitation, saturation of the core in a transformer draws a significant exciting current, which can cause malfunction of a current-differential relay. This paper proposes a modified-current-differential relay for transformer protection. The relay calculates the core-loss current from the induced voltage and the core-loss resistance as well as the magnetizing current from the core flux and the magnetization curve. Finally, the relay obtains the modified differential current by subtracting the core-loss and the magnetizing currents from the conventional differential current. A comparative study of the conventional differential relay with harmonic blocking is presented. The proposed relay not only discriminates magnetic inrush and over-excitation from an internal fault, but also improves the relay speed.
Keywords
Core-loss current; Harmonic blocking; Magnetic inrush; Magnetizing current; Over-excitation;
Citations & Related Records
연도 인용수 순위
  • Reference
1 C. D. Hayward, 'Harmonic-Current-Restrained Relays for Transformer Differential Protection', AIEE Trans., Vol. 60, pp. 377-382, 1941
2 C. H. Einvall, and J. R. Linders, 'A Three-phase Differential Relay for Transformer Protection', IEEE Trans. on PAS, Vol. 94, No. 6, pp. 1971-1980, Nov./Dec. 1975
3 G. D. Rockefeller, 'Fault Protection with a Digital Computer', IEEE Trans. on PAS, Vol. 88, No. 4, pp. 438-462, Apr. 1969
4 K. Inagaki, M. Higaki, Y. Matsui, K. Kurita, M. Suzuki, K. Yoshida, and T. Maeda, 'Digital Protection Method for Power Transformers Based on an Equivalent Circuit Composed of Inverse Inductance', IEEE Trans. on PWRD, Vol. 3, No. 4, pp. 1501-1510, Oct. 1988
5 M. S. Sachdev, T. S. Sidhu, and H.C. Wood, 'A Digital Relaying Algorithm for Detecting Transformer Winding Faults', IEEE Trans. on PWRD, Vol. 4, No. 3, pp. 1638-1648, Jul. 1989
6 Y. C. Kang, B. E. Lee, S. H. Kang, S. S. Kim, and J. K. Lee, 'A Transformer Protective Relaying Algorithm Using the Ratio of Induced Voltages', IEEE PES 2001 SM, Vancouver, BC, Canada, July 15-19, 2001   DOI
7 P. Bastard, P. Bertrand, and M. Meunier, 'A Transformer Model for Winding Fault Studies', IEEE Trans. on PWRD, Vol. 9, No. 2, pp. 690-699, Apr. 1994
8 Electromagnetic Transients Program Theory Book, Chapter 2, 1986
9 C. W. Mathews, 'An Improved Transformer Differential Relay', AIEE Trans. Part III, Vol. 73, pp. 645-650, Jun. 1954   DOI   ScienceOn
10 E. L. Harder, and W. E. Marter, 'Principles and Practices of Relaying in the United States', AIEE Trans. Part II, Vol. 67, pp. 1005-1022, 1948
11 R. L. Sharp, and W. E. Glassburn, 'A Transformer Differential Relay with Second-Harmonic Restraint', AIEE Trans. Part III, Vol. 77, pp. 913-918, 1958   DOI
12 A. G. Phadke, and J. S. Thorp, 'A New Computer- Based Flux-Restrained Current-Differential Relay for Power Transformer Protection', IEEE Trans. on PAS, Vol. 102, No. 11, pp. 3624-3629, Nov. 1983
13 A. G. Phadke, and J. S. Thorp, Computer Relaying for Power Systems, Research Studies Press LTD., 1988
14 A. Giuliante, and G. Clough, 'Advances in the Design of Differential Protection for Power Transformers', 1991 Georgia Tech. Protective Relaying Conference, Atlanta, GA, pp. 1-12, May 13, 1991