All-Electric LNG Liquefaction Plants: Technical Challenges and Possible Concept Solutions

This paper discusses technical challenges posed by large all-electric liquefaction plants, in which the plant refrigeration compressors are driven by electric motors powered by gas-turbine driven electric power generators. The focus is on the interaction between large compressor drives and the electrical system. One issue is interharmonics in the subharmonic range from line-commutated inverter drives, which can cause subsynchronous resonance problems. Furthermore, a few alternatives for improving robustness of grid-connected liquefaction plants against voltage dips are presented.