Ecology and economy decide for 50000 HP electric turbocompressor drivers

Since the summer of 1997 three natural gas turbocompressors are driven by adjustable speed supersynchronous motors of 38 MW @4200 rpm-the largest LCI drives ever built for that speed up to now. Restrictions on harmonics imposed by the utility, special network conditions, pressure by ecological political groups, and life-cycle economics were decisive in the choice of drive systems. Selection and design criteria for the drivers, network considerations, and first year positive operating experience are addressed by the client and the manufacturer. A subsequent project involving similar high speed electric motor drivers of 25 MW with active magnetic bearings for a "dry" turbocompressor string concludes the paper that primarily addresses prospective users of such systems.