Abstract
Auto-transformer feeding system is standard equipment for power supply to high-speed trains and prevention of inductive interference with the telecommunication lines on the AC electrified Shinkansen lines in Japan.
In the present AT feeding system in which the feeder side of the feeding transformer is not grounded, the insulation level on the feeder side at the substation is set twice as high as the vehicle voltage.
For the purpose of economizing on the substation power system, the authors have developed new methods adopting a three-winding Scott-connected transformer to make the insulation level on the feeder side a half of the present value and additionally employing a series capacitor with a simplified structure to compensate for the voltage drop.
This paper describes the structure and characteristics of the three-winding transformer, and insulation level reduction method using it.
Specifically various features of the system are discussed through simulation of feeding performance by multi-circuit networks analysis and study of various phenomena under use of the series capacitor.
Furthermore by confirmation tests executed in the Osaka area of the Tokaido Shinkansen line,
the practical applicability of the system is proved.
