| Title |
Development of Ground Fault Protective Relaying Schemes for DC Traction Power Supply System |
| Authors |
정상기(Chung Sang-Gi) ; 정락교(Jeong Rag-Gyo) ; 조홍식(Cho Hong-Sik) ; 이안호(Lee Ahn-Ho) ; 권삼영(Kwon Sam-Young) |
| Keywords |
DC급전 ; 보호계전 ; 지락보호 ; 도시철도 ; 지락사고 ; 전력공급시스템 ; |
| Abstract |
In DC tracking power supply system, ground faults are currently detected by the potential relay, 64P. Though 64P relay detects ground fault, it cannot Identify the faulted region which causes long traffic delays and safety problem to passengers. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. One is bus differential protective relay and the other is ground overcurrent protective relay. Both type of relays is similar in principle to the ordinary bus differential protective relay and the ground overcurrent relay used in other power system. In DC traction power supply system, since it is ungrounded, ground fault current is not big enough to operate those relays. To solve the problem, a current control device, called device 'X', is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. Algorithms for these relays are developed and their validity are verified by EMTP simulation. |