KIEE International Transactions on Power Engineering

대한전기학회 (The Korean Institute of Electrical Engineers)
권호 표지

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)
  • 발행 : 2005.03.01
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초록

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.

키워드

참고문헌

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