Disturbances affecting essential loads in high-speed railway systems

A thorough analysis is given of the various phenomena responsible for the main disturbances involving essential loads in high-speed railway systems. Subsequently, a new system configuration is properly highlighted and discussed. The architecture of the proposed system replaces the already adopted architecture, which was responsible for many problems of the UPSes supplying the essential loads. The main differences between the two layouts mainly involve LV systems supplied by the UPSes. Actually, the BT system configuration changed from TN-S to IT with distributed neutral; in addition, an isolation transformer was inserted to supply the remote sensible loads. The aim of the isolating transformer was to reduce disturbances reaching the UPS through greatly exposed cables. In practice, these cables are very long and installed side by side along both the electrical MV power lines and the linear earth plate of the railway system.