Abstract: Statistics show that the faults of the DLN 2.0+ combustion system happen most frequently in the operation of GE 9FA gas turbines. This paper introduces the structure of GE 9FA gas turbine DLN 2.0+ combustion system and the action sequence of each equipment in this system during the gas turbine startup, operation and shutdown process. The cause analysis on gas leak test failure, Gas Fuel Stop Valve (FSV) fault, Speed Ratio Valve (SRV) fault and gas purge fault is conducted, and the corresponding improvement measures are put forward. The application practice shows that the failure rate is significantly reduced after the improvement measures are taken.

Key words: GE 9FA gas turbine, DLN 2.0+ combustion system, cause analysis, improvement measure