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지상변압기의 내부 보호장비 작동을 위한 MCA 보호협조에 대한 연구

A study on Protective Coordination of MCA for Performing of the Pad Mounted Transformer's inside Protective Device

  • Hyun, Seung-Yoon (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Kim, Chang-Hwan (KEPCO Research Institute, Korea Electric Power Corporation)
  • 투고 : 2021.09.16
  • 심사 : 2022.04.28
  • 발행 : 2022.06.30

초록

KEPCO's plan is undergoing a trial operation to replace the open-loop section with ring main units configuration where underground distribution lines are installed, by linking the multi-way circuit breakers auto (MCA) on the power side of each pad-mounted transformer. However, ring main units application mentioned above may cause the ripple effects, when implementing the configuration without a study of protection coordination. Because ring main units with classical pre-set protection devices contribution in fault condition didn't consider yet. For the reliable ring main units operation, it is necessary to resolve several protection issues such as the protection coordination with substation side, prevention of the transformer inrush current. These issues can radically deteriorate the distribution system reliability Hence, it is essential to design proper protection coordination to reduce these types of problems. This paper presents a scheme of ring main units' configuration and MCA's settings of time-current curves to preserve the performance of protection coordination among the switchgears considering constraints, e.g. prevention of the ripple effects (on the branch section when a transformer failure occurs and the mainline when a branch line failure occurs). It was confirmed that the propagation of the failure for each interrupter segment could be minimized by applying the proposed TCC and the interrupter settings for the MCAs (branch, transformer). Further, it was verified that the undetected area of the distribution automation system (DAS) could be supplemented by having the MCA configurated ring main units operate first, instead of the internal protection equipment in the transformer such as the fuse, STP when a transformer failure occurs.

키워드

과제정보

This research was supported by Korea Electric Power Corporation under Grant R20DA25.

참고문헌

  1. 현승윤, "공급신뢰도 개선형 지중계통 차단기 운용방안", 전력연구원, 2020
  2. "25.8kV 에폭시 절연 고속도 전원절환 다회로 차단기(지중용)", 한전 일반구매규격(GS-5925-0136), 2010