Commissioning Challenges for Upgrading Gas Turbines to Combined Cycle

This paper presents the challenges that were introduced during the commissioning of an upgrade of an existing oil field from a simple-cycle gas turbine to a combined-cycle gas turbine. The combined-cycle block consists of three gas turbines and one steam turbine from two manufacturers. The paper discusses the impact on processes during the upgrade and the main milestones of commissioning the steam turbine. New modes of running steam turbines that were introduced are compared with the existing gas turbines. The steam coupling between the gas turbine and steam turbine is verified during field tests. The impacts of the steam coupling on the existing generation control system and load-shedding system are explained. Modified steam equations were updated during commissioning. The updated automatic generator control philosophy is also highlighted. Actual field test results are presented in the paper.