Wide Area Protection System for AT Traction Power Supply

All-parallel AT traction power supply has become a commonly used power supply mode in China high-speed railway. The current relay protection system for the all-parallel AT traction power supply mode has the defect that it will cause comparatively wider area and longer time of power outage. A wide area protection system for AT traction power supply was developed in this paper. The system constructed a fast interactive information network with one feeding section as a unit, which achieved information sharing among protection devices in traction substations, AT substations and district substations. The system solved the problem of which relay should trip based on information sharing and comprehensive analysis. The system could make a fast and selective trip, which could reduce the power outage range. Dynamic simulation tests were done to test the system by RTplus. The tests showed that the system could protect all-parallel AT traction power supply effectively. The fault location error was less than 500m.The response time was reduced by about 5s.