Page 66 - 360.revista de Alta Velocidad - Nº 5

Martínez Acevedo, José Conrado. Berrios Villalba, Antonio. Peregrín García, Eugenio.

Figure 10. AT system. (Source: Author).

5.3 Coaxial cable

As shown in Figure 11, the coaxial cable feeding system features a coaxial cable laid along
the track. Every several kilometers, the inner conductor is connected to the contact wire
and the outer conductor is connected to the rail. The cable itself is very expensive but the
conductor layout is simple, making it ideal for use where space is limited. Japan is the only
country that uses this system (the Tokyo sections of the Tohoku Shinkansen and Tokaido
Shinkansen).
In comparison to the overhead line, the coaxial power cable has extremely small loop
impedance. Therefore, the load current is boosted in the coaxial power cable from the
connection with the catenary. This results in a rail current distribution similar to that of AT
system, significantly reducing the inductive interference.

64 360.revista de alta velocidad