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

The Korean Institute of Electrical Engineers (대한전기학회)
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Discrimination Method of Internal and External Fault of Current Differential Relay using Instantaneous Value of Current in Case of Fault with One end CT Saturation

편단 CT 포화 고장 발생시 양단 전류 순시치를 이용한 전류차동계전기의 내·외부 고장위치 판별방안

  • Lee, Myoung-Hee (Dept. of Electrical Engineering, Sungkyunkwan Univ.) ;
  • Choi, Hae-Sul (Dept. of Electronic, Electrical and Computer Engineering, Sungkyunkwan Univ.) ;
  • Kim, Chul-Hwan (School of Information and Communication Engineering, Sungkyunkwan Univ.)
  • 이명희 (성균관대 대학원 전기공학과) ;
  • 최해술 (성균관대 전자전기컴퓨터 공학과) ;
  • 김철환 (성균관대 정보통신대학)
  • Received : 2012.07.31
  • Accepted : 2012.10.30
  • Published : 2012.12.01
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Abstract

This paper presents a simple and practical method which enables to prevent malfunction of protection relay due to differential current caused by one end CT saturation in case of external fault. This method uses difference of magnitude(instantaneous value) between the both end current just before the occurrence of differential current without a separate method to CT staturation detection. One end CT saturation is simulated by current transformer model using type-96 component and the presented method is verified by using EMTP MODELS with respect to internal and external fault with one end CT staturation. The presented method distinguished rightly bewteen external and internal fault with one end CT saturation. This information can be used to prevent malfunction of current differential protection relay in case of external fault. And this method is not affected by sampling rate and has no calculation burden, so it will be applicable to differential current protection relay with ease.

Keywords

References

  1. Mitsubishi Electric Corporation, Instruction manual of MDT-H, PCM current differential relay scheme for KEPCO.
  2. Y.C.Kang, S.H.Ok, S.H.Kang, "An Algorithm for Detecting CT Saturation", KIEE, Vol. 50A, No. 6, pp275-278 2001
  3. S.H.Kang, EMTP Summer Course, "System Protection Modelling and Application Case Study", August, 2006.
  4. Gabor Furst, "MODELS PRIMER", 1995.