精选优质文档-倾情为你奉上AbstractIncreasing attention has been shown in recent years in the a.c. electrification of railway traction systems and a number of established systems now exist throughout the world. Where the traction system is supplied directly from a high-voltage national-grid network, a common component of such schemes is a step down transformer connection between the two systems. The electrical, mechanical and thermal design of these transformers is subject to a number of special consi
