60-cycle to 50-cycle Conversion of an F-class Gas Turbine

摘要

In this paper the potential for conversion of an F-class combustion turbine from generating 60-cycle powerto 50-cycle power will be examined. These turbines are rated for a nominal 60-cycle ISO output of175-185 MW. With the gas turbine boom of the late 1990s and the cancellation of several GT basedprojects that followed, a surplus of GTs has been created. This surplus has resulted in the review ofalternative options for installation at other plants or resale of GTs other users. One potential solution is theconversion of a GT into a 50-cycle machine for installation in other markets around the world. If this typeof conversion proves feasible, it also opens the door for the 60-cycle designed GTs to be marketed overseasto compete with original 50-cycle equipment.Three potential options for creating 50 Cycle power with a 7FA are identified:1. Operate the combustion turbine generator (CTG) at 3000 RPM to generate energy at50 Hz.2. Operate the CTG at 3600 RPM to generate energy at 60 Hz and install an invertor,external to the CTG, to convert 60 Hz potential to 50 Hz.3. Operate the turbine at 3600 RPM and the generator at 3000 RPM by installing a gearbox(speed reducer) between the turbine and the generator.The options were researched and pricing was obtained on those that were considered feasible. GE was alsocontacted to provide input and identify potential difficulties for each of the scenarios. The results for eachof the options are provided below.