Conversion of Gas Turbine Drivers to Electric Motor Driven Planetary Gear Systems for Centrifugal Compressor Service
Gas transmission companies often look to replace antiquated and/or inefficient compressor drivers along their system. One option to evaluate is an electric-motor option. This paper presents a case study of the process of optimization and evaluation of two electric-motor driver options for a compressor station containing gas-turbine driven centrifugal compressors. In this case, the chosen option was the replacement of the turbine with a constant-speed electric motor driving a planetary gear--box system, which varies the speed to the centrifugal compressor. The project involves four compressor units each rated at 9,275 horsepower that have recently been installed and commissioned, representing the first installation in the USA of this type of system for gas transmission service. The units were installed and commissioned in 2001. Finally, the paper presents a brief summary of the workings of a planetary gear-box system and its inherent characteristics.