Medium Voltage Softstarter MCS 6C in service

F&S delivered, installed and commissioned a thyristor based softstarter at Deutsche Bahn frequency converter plant Bützow.The 6.3 kV, 1 kA softstarter is utilized to accelerate and synchronize a “10 MVA 50 Hz / 16.7 Hz synchronous motor generator set” to both grids. Therefore a new approach of W3C converter control - the synchronous softstart technology – was introduced with this project. The motor DOL current, of approx. 4-5 kA, was reduced to less than 500 A during start. Further, using synchronous softstart technology, leads to a smooth grid coupling by meeting the three common synchronization criteria. As a result, mechanical and thermal load during startup and synchronization was reduced significantly.