Recently, a world’s first ever power electronic traction transformer (PETT) for 15 kV, 16 2 /3Hz railway grid, has been newly developed, commissioned, and installed on the locomotive, where it is presently in use. This marks an important milestone in the traction world. The design and development of the PETT are described in this paper, where a low-voltage (LV) PETT prototype is presented. It has been designed for the purposes of control hardware and software commissioning, thus serving a role of an analogue simulator. In this paper, emphasis is placed on the overall system requirements, from where control system has been developed, implemented, and successfully commissioned. The development of a 1.2MVA medium-voltage PETT prototype will be reported separately in accompanying paper.