The Transactions of the Korean Institute of Electrical Engineers (대한전기학회논문지)

The Korean Institute of Electrical Engineers (대한전기학회)
권호 표지

Study on the Asymmetrical Fault Currents and the Operating Time Characteristics of OCR

비대칭과도 전류와 과전류계전기의 동작시간 특성에 관한 연구

  • 김남호 (강원대 공대 전기공학과) ;
  • 김일남 (한국전려공사 기술연구원 계통연구실) ;
  • 박종근 (서울대 공대 전기공학과)
  • Published : 1992.09.01

⟨ Previous Next ⟩

Abstract

As the TC(time-current) curve corresponding to symmetrical time invariant RMS value has been traditionally chosen and used for setting the relay, it has caused the misoperation errors on relay coordination because of CT secondary current being actually an asymmetrical time varying RMS value. In this paper, an algorithm for calculating the relay operating time is developed to study the asymmetrical effect using the step-by-step method. We represent the relay operating time errors between with and without DC offset versus PSM(plug setting multiplier), TMS(time multiplier setting) and X/R ratio. And also we present the correction factor. Finally we confirm the validity of this technique through the case study.

Keywords