The Transactions of The Korean Institute of Electrical Engineers (전기학회논문지)

The Korean Institute of Electrical Engineers (대한전기학회)
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Current Differential Relaying Algorithm for Power Transformer Protection Operating in Conjunction with a CT Compensating Algorithm

보상 알고리즘을 적용한 변압기 보호용 전류차동 계전방식

  • 강용철 (전북대 대학원 전기공학과) ;
  • 박종민 (전북대 대학원 전기공학과) ;
  • 이미선 (전북대 대학원 전기공학과) ;
  • 장성일 (전북대 대학원 전기공학과) ;
  • 김용균 (한국IED Eng.) ;
  • 소순홍 (전북대 대학원 전기공학과)
  • Published : 2007.11.01
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Abstract

Current differential relays may maloperate during magnetic inrush and over-excitation because a significant differential current is produced. To prevent maloperation, the relays adopt some harmonic components included in the differential current. The harmonic restraints may increase the security of a relay but cause the operating time delay of a relay when an internal fault occurs. Moreover, the operating time delay is more increased if a current transformer (CT) is saturated. This paper describes a current differential relaying algorithm for power transformer protection with a compensating algorithm for the secondary current of a CT. The comparative study was conducted with and without the compensating algorithm. The performance of the proposed algorithm was investigated when the measurement CT (C400) and the protection CT (C400) are used. The proposed algorithm can compensate the distorted current of a CT and thus reduce the operating time delay of the relay significantly for an internal fault with CT saturation.

Keywords

References

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