Coaxial Cable Feeding System

-
The Coaxial Cable Feeding System is a Feeding System in which coaxial power cables are laid along the tracks and every few kilometres the internal conductor of the coaxial cable is linked to the contact wire while the external conductor is linked to the rail.
 


In the method, the overhead contact line system (OCS) configuration is straightforward so suitable for narrow sections and tunnel sections.

Because the reciprocal impedance of the coaxial cable is about 1/10 in comparison with an aerial system, the load current is drawn off to both terminals of the coaxial cable, providing a telecommunications induction-suppressing effect like that of the AT Feeding System.


On the other hand, because the capacitance between the internal and external conductors of the coaxial cable is large, there is a need to investigate a phenomenon whereby the harmonic current is enlarged by the resonance between the capacitance and the inductance on the power supply side.

The Coaxial Cable Feeding System has been adopted for Tokaido Shinkansen and Tohoku Shinkansen.

Comments

Post a Comment

Popular posts from this blog

AT Feeding System

-
Image
An auto transformer is a transformer in which two windings share a common part, where the common part is called a common winding , and the parts in series with the circuit are called series windings . The product of the voltage and current of the series winding or common winding is known as the self capacity and indicates the size of the AT. Meanwhile, the capacity that can be supplied to the circuit is called the line capacity . When the turns ratio is 1:1 , the line capacity is two times the self capacity . The feeding circuit is configured from feeder lines, overhead contact lines, neutral wires, and auto transformers (AT) . The AT is connected in parallel between the feeder line and the overhead contact line, and the neutral point of the AT is connected to the rail. When the load current is split between the rails fore and aft of the train and flows to coil N1 of the AT via the neutral point, enough current to cancel out the ampere-turns flows to coil N2. This
Read more

Traction Substation (SS)

-
Image
A Traction Substation steps down an AC three-phase power supply to 25 kV, and converts the voltage to two single phases which are then supplied to the overhead contact line. The facilities in the SS are broadly classified into four categories, power-receiving facilities , power transformation facilities , power traction facilities , and remote control facilities. (1)The power-receiving facilities The power-receiving facilities include a power-receiving disconnecting switch , circuit breakers , lightning arresters , voltage transformers , and protective relays . Those facilities are installed for drawing and receiving power via two lines from a three-phase high-voltage bus line of a power  company. (2)The power transformation facilities The power transformation facilities are configured from AC feeding transformers , disconnecting switches and operating transformers or other components. (3)The power traction facilities The power traction facilities are configured from d
Read more

Contact wire voltage

-
Image
AC feeding voltage of a conventional line (which means "urban train without high-speed") is a single-phase AC voltage of 20 kV, but a standard voltage of the Shinkansen Overhead Contact Line is 50Hz AC voltage of 25 kV . The main reasons for adopting an AC voltage of 25 kV as the standard voltage are as follows: (1) With 1,500 V DC electrification, the collected current is large, the overhead contact line is thick, and the traction substation interval is 3 to 5 km, which means high construction costs . (2) With 1,500 V DC electrification, the power collectors are heavy and tracking during high-speed operation is difficult. (3) With 1,500 V DC electrification, selective shutting off a fault current is difficult because the fault current value and load current value are comparable. (4) Because the Shinkansen is a new line, and tunnels and other facilities are newly provided, sufficient insulation clearance can be secured from the outset, and there are barely any pr
Read more