CONVERTER FOR CONNECTING SMES TO ELECTRICAL POWER SUPPLY SYSTEMS

The operation of SMES units at public power supply systems includes a number of specifications with regard to the connecting converter. After a general review of SMES application and a brief presentation of the pilot plant to be installed at the Institute of Technology, Munich, two converter concepts suitable for operating SMES units in electric utility systems are discussed. As long as experi­mental studies on SMES are of main interest, one can do with line-coramutated rectifiers. However, to meet the requirements of reliable network operation pulse-controlled inverters have to be used, where voltage source inverters (VSI) turned out to be the best solution. Both inverter and capacitor d.c voltage link form a fast-acting VAr controller for reactive current feed, network balancement and harmonics elimination. A static compensator of this type can be easily completed by each kind of storage like SMES, batteries and flywheels making it a universal control component for use in a wide range of applications in power supply networks.