| Title |
A Study on the Protection of the Auto Transformer according to the Influence of Return Current on Adjacent Line at Feeding System |
| Authors |
이동호(Dong-Ho Lee) ; 최용은(Yong-Eun Choi) ; 박원찬(Weon-Chan Park) ; 김재문(Jae-Moon Kim) ; 강정원(Jeong-Won Kang) |
| DOI |
https://doi.org/10.5370/KIEE.2020.69.10.1499 |
| Keywords |
Return Current on Adjacent Line; AT Feeding System; Protection; Ground fault; Overcurrent relay |
| Abstract |
When a ground fault by contact wire or feeder occurs on the AT feeding system, the return current on adjacent lines resulted by a ground fault effect on considerable shock to the AT on the normal feeders, but does not protect the AT from excessive return current on adjacent lines. AS a result, in extreme cases, the AT is burned, causing a secondary feeding failure due to a power supply failure in the up and down lines. In this paper, we proposed the installation of an overcurrent relay(OCR) to protect the AT from the return current on adjacent lines. By means of the OCR, the magnitude of the return current was checked, and circuit breaker(CB) was cutoff on the healthy phase at the measurement of the return current on adjacent lines exceeding more than 7 times of rated current of AT. Through this study, it is expected that the reliability of the power supply system will be improved by preventing not only the shock on the healthy AT but also secondary accidents. |