Active damping of inrush and DC-currents for high temperature Superconducting (HTS)-transformers on rail vehicles

The 1-MVA-HTS-transformer made by Siemens promises a high-efficient drive component as has been reported-even if a converter is used and additional AC-losses occur. HTS-transformers on rail vehicles have to meet different demands on the energizing to the grid. Due to the small resistance, the damping of DC-components of inrush currents or due to the bouncing of pantographs is insufficient. Additional damping devices, especially a switched resistor, promise a well-working solution. On the other hand, additional costs and mounting space will be caused. But what would be possible, if we would consider the use of already implemented on-board equipment like traction converter to fulfill the given demands on the inrush current? The DC-components may be damped by an active switching of the installed converters. Investigations, results and influences on the transformers behavior of the mentioned operations by using the on-board converters to meet the demands of railroad companies will be presented here.