Short-Circuit Characteristics Analysis of New Continuous Cable Traction Power Supply System

New continuous cable traction power supply system (CCTPSS) can achieve long-distance transmission and reduce the number of electric phases. However, the two-stage power supply mode leads to the complex structure of the system. In order to reveal the short-circuit characteristics of CCTPSS, the two-port network parameters of traction cable and catenary-rail of unit length were established. Each sub-network was cascaded and equated with a two-port network, which was then transformed into a Ⅱ-type circuit for modeling the distribution parameters of the traction cable and catenary-rail of any length. The locomotive voltage drops after short circuit of catenary. Therefore, considering the coupling relationship between the train and the network, the short-circuit current and voltage were solved by iterative calculation. The accuracy of the calculation method was validated by simulation. Finally, the electrical characteristics of different short-circuit types were analyzed, with emphasis placed on the influence of distributed capacitance on short-circuit current and voltage. The results show that the distributed capacitance can increase the short-circuit current and, under different short-circuit conditions, the output voltage of traction transformer. The short-circuit current of catenary is jointly provided by traction transformers on both sides, and the farther away from the short-circuit point is, the less current is provided. The cable phase-to-phase short circuit has the greatest impact on the operation of the non-fault-circuit locomotive.