Inter-tripping Protection Scheme for Feeding Sections of High-Speed Railway Based on Impedance Features

In order to achieve a rapid and selective protection of cross-coupling AT feeding systems for high-speed railways, an inter-tripping protection scheme for feeding system based on impedance features was proposed. According to loop voltage equations and Kirchhoff's current law, the short-circuit impedance in substation, AT station, and section station was derived;and the relation between short-circuit impedances and fault position was analyzed. In the novel protection scheme, protection elements of distance zone Ⅰ are respectively installed in substation, AT station, and section station, and integrated via inter-tripping signals. When any protection element detects a fault, it will trip the related circuit breaker in the station and send an inter-tripping signal to the other protection elements for the same feeding section to complete fast fault isolation. Simulation results show that the proposed scheme can isolate the fault feeding section within 100 ms after fault, while at the same time not interrupting the power supply of the parallel feeding section. Therefore, the requirement of selectivity and speediness for protection are both satisfied.