Traction Substation (SS)

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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 disconnecting switches, AC feeding circuit breakers, voltage transformers, and auto transformers, or other components.

The feeding lines are installed direction-wise or line-wise, and a feeding circuit breaker is installed for each feeding line.
An interrupter for bulk feeding system is further installed.

The auto transformer is provided with a motorized-type disconnecting switches enabling isolation from the feeding line; a change-over switch is installed line-wise and adopted a dual system.

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