Search

For installation in the public electric power grid of the city of Augsburg, Germany, a resistive superconducting fault current limiter (SFCL) was designed, constructed, tested and operated in the framework of a partially funded project ‘ASSiST’. Right from the beginning, it was agreed to aim for a prolonged operation even after closure of the project. This endeavor has been started due to a fundamental need to limit the prospective fault currents at a feeder point of the grid and in order to create long-term operational experience on a device seamlessly integrated into commercial grid components and switchgear, thus demonstrating a high level of readiness for widespread application. It revealed that the SFCL was of robust design – withstanding all electrical tests including a special two-phase fault and sustaining stable cryogenic conditions even during partial outages of the cooling system – and that the technology is reducing loss by shunt reactors. Furthermore, due to the control equipment on medium voltage level, valuable insights on grid behavior could be gained. The extended operation for 4 years has clearly shown the performance and robustness of SFCL technology in feeder points on MV level and provides a reference point for further commercialization. [ABSTRACT FROM AUTHOR]

Main applications for rotating electric synchronous machines are given as generators and motors; a small niche can also be found in synchronous condenser-applications. High temperature superconducting (HTS) rotating machines show several significant advantages over machines built in conventional techniques. These are mainly increased efficiency, higher power density, and enhanced electrical stability. Especially for on-board applications, these properties may be decisive to save fuel and space and improve the capabilities. In the past, basic programs were carried out to demonstrate in principle the possibility to build such machines. Meanwhile these programs have shown great success and the feasibility of HTS machines for such applications has come into reach. For that reason developments for HTS machines in the megawatt-range are now being in progress, for propulsion purposes as well as for power generation applications. Started with the built of a 400 kW model motor that has operated successfully for more than two years, Siemens is now being engaged in the development of HTS machines for all electric ship application in the megawatt-range. A demonstrator for a 3600 rpm 4 MVA generator has been set up in the Nuremberg test facility for extended type and system testing. Results of tests with both machines will be presented. Technical implications of this new technology for ship-borne application will be discussed together with general economic assessments. [ABSTRACT FROM AUTHOR]