Feeding Circuit Configuration
A general configuration of an AC feeding circuit is shown in below figure. Each railway wayside is provided with Traction Substations (SS) , Sectioning Posts (SP) for sectioning of feeding network, Sub-Sectioning Posts (SSP) for limited sectioning of feeding network, and Auto Transformer Post (ATP) which has only auto transformer. The Traction Substation interval in the case of a conventional line is 30 to 50 km for the BT Feeding System and 90 to 110 km for the AT Feeding System , and in the case of a Shinkansen, 20 to 60 km for the AT Feeding System . And the auto transformer interval is about 10 km for Shinkansen AT Feeding System , so not only SS but also SP, SSP and ATP have the auto transformers.