Journal of the Korean Society of Safety (한국안전학회지)

The Korean Society of Safety (한국안전학회)
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A Study on the Operating Characteristics of the Aged ELCB according to the Overcurrent

노후화된 누전차단기의 과전류 동작 특성에 관한 연구

  • Ye Jin Park (Department of Fire & Disaster Prevention Engineering, Daejeon University) ;
  • Sin Dong Kang (Department of Fire & Disaster Prevention Engineering, Daejeon University) ;
  • Jae-Ho Kim (Department of Fire & Disaster Prevention Engineering, Daejeon University)
  • 박예진 (대전대학교 소방방재학과) ;
  • 강신동 (대전대학교 소방방재학과) ;
  • 김재호 (대전대학교 소방방재학과)
  • Received : 2023.09.04
  • Accepted : 2023.10.16
  • Published : 2023.10.31
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Abstract

This study analyzes the operational characteristics of 311 aged and non-aged residual current circuit breakers (RCCBs) in low-voltage consumer contexts. It investigates the influence of external temperature and harmonics based on the rated current multiples. To simulate temperature variations, a convectional oven was used around the circuit breakers. Additionally, the generation of harmonic reference signals and data measurement for overcurrent experiments were conducted using NI SCXI, myDAQ, and LabVIEW. An observation revealed that as the ambient temperature increased, the operating time of RCCBs decreased in the time delay region. This was attributed to the faster response or bending of the bimetal, which is the tripping element. However, aged RCCBs encountered challenges with tripping outside the protective curve. The operating time of the circuit breakers exhibited an acceleration influenced by the order and content of harmonic currents, potentially leading to malfunctions. Aged RCCBs demonstrated faster operating times than their non-aged counterparts. However, the difference in operating time varied based on the manufacturer's and operating environment of the RCCBs. Frequent malfunctions of RCCBs can result in power outages. In cases where these circuit breakers fail to operate, they can lead to secondary damages, including electrical fires and shocks. Consequently, it is imperative to consider the operating environment of RCCBs and provide appropriate replacement cycles to mitigate these risks.

Keywords

Acknowledgement

This research was supported by the National Research Foundation of Korea (NRF) grant funded by the korea government (Mist) (NRF-2022R1A2C1004599).

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