• 제목/요약/키워드: Symmetrical short - circuit current factor

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포화를 방지하기 위한 보호용 철심 변류기 설계 방법 (A Design Method of Iron-cored CTs To Prevent Satruation)

  • 이주훈;강상희;강용철;이승재;배주천;안준기;이청학;이정택
    • 대한전기학회논문지:전력기술부문A
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    • 제48권2호
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    • pp.119-126
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    • 1999
  • Current transformer (CT) saturation may cause a variety of protective relays to malfunction. The conventional CT is designed that it can carry up to 20 times the rated current without exceeding 10% ratio error. However, the possibility of CT saturation still remains if the fault current contains substantial amounts of ac and/or dc components. This paper presents a design method of iron-cored CTs for use with protective relays to prevent CT saturation. The proposed design method determines the core cross section of the CT; it employs the transient dimensioning factor to consider relay's operating time (duty cycle) and dc component as well as ac components contained in the fault current, and symmetrical short-circuit current factor to consider as well as ac components contained in the fault current, and symmetrical short-circuit current factor to consider the biggest fault current. The method designs the cross section of CTs in cases of reclosure and no reclosure.

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