Innovative protection system for separation section between 15 kV a.c. and 3 kV d.c. railway networks

The proximity between two different railway supply systems, ac and dc power systems, could bring about to the propagation of interferences from one system to the other. Furthermore, unexpected overvoltages and overcurrents could appear due to the breakdown of equipments installed in the interconnection point. The protection system considered is placed in the Chiasso station, where there are several constraints, among which a limited space available to realize a traditional separation section. The present paper proposes a new protection system from faults between the Italian d.c. railway line and the Switzerland a.c. one. The innovative system will be in operation in a short time. In order to simulate several phenomena, a specific Matlab-Simulink model has been implemented and used to simulate the system proposed.