Ride-Through of Medium Voltage Synchronous Machine Centrifugal Compressor Drives

Medium voltage (MV) synchronous machines (SMs) are expected to ride through adjustable speed drive (ASD) faults, excitation faults, system faults/disturbances and supply transfers. Models suitable for direct-on-line and ASD ride-through simulations are discussed. Case studies, simulation and test results are presented for an 11 kV ASD for 17 MW SMs and for a 55 MW SM. It is shown that line fed and ASD fed SMs can survive system faults and voltage dips without additional compensation or energy storage. ASD fed SMs have far better survivability characteristics than line fed SMs. SMs can ride through ASD faults associated with fault tolerant schemes when correctly configured. Boundary supply transfer angles are determined to eliminate unacceptable transients. Aspects requiring special attention for SMs in addition to the induction motor (IM) ride-trough requirements are highlighted. Recommendations are provided to improve availability of ASD started/driven SMs.