Siemens has delivered a steam turbine in the capacity range up to 10MW that, for the first time, operates almost entirely without lubricants. The bearing systems consist of completely oil-free, air-cooled, electromagnetic bearings. The valve actuators operate with only a minimum oil supply and are controlled via software-controlled electric motors. The trial run of the first turbine equipped with magnetic bearings was successfully completed in Vattenfall’s lignite-fired Jänschwalde steam power plant, located in the southeast of the German state of Brandenburg, after which the model SST-600 steam turbine was officially handed over to Vattenfall. The turbine has been running reliably in regular full-load operation since February 2015, at speeds of up to 5,700rpm. It is used as a feedwater pump drive.
The first SST-600 steam turbine with magnetic bearings was developed in co-operation with the University of Zittau/Görlitz. This co-operation included the design, setup, operation and testing of a common test bay to demonstrate the feasibility of a steam turbine equipped with magnetic bearings. Siemens was responsible for technical project management of the test bay and the prototype project, for design of the steam turbine, design of the magnetic bearings and for the construction, commissioning and trial operation of the magnetic bearing steam turbine.