抄録
In this paper, we describe the development of AC railway traction current return arrangement for Hokuriku Shinkansen automatic train control (ATC) system. The purpose here is to reduce induced current effects on a linking section in which the two different frequencies (50/60Hz) of the AC electric supply systems meet.
The Shinkansen ATC system, which is required principally as a safety feature to prevent trains from exceeding speed restrictions or passing signals at danger, makes use of the running rails as the transmission medium. In the system, audio frequency track circuits adopting a single side band (SSB) modulation are used both to detect trains and to transmit maximum permitted speed information.
In the Shinkansen SSB modulation, the carrier frequencies are generated by the power sources and synchronized with them. Therefore, this ATC system suffers electrical interference from high harmonic voltage that is synchronized with the different power sources.
To be immune to this interference, we developed an arrangement dealing with traction return current and a composition of track circuits as a result of simulations and practical measurements.
