Tuning of static excitation systems (SESs) to enhance the performance of sin gas turbine (GT) generators near an electric are furnace (EAF) feeder has been successfully accomplished. The operation of these EAFs causes severe and long duration voltage fluctuation at the generator bus. Frequent generator tripping was reported when the adjacent EAFs were in operation. Preliminary field measurements and computer simulation indicated that the SESs did not have sufficient damping under this type of voltage fluctuation. By the adjustment of the SES gains and time constants according to the guideline set by the IEEE Standard 421.2, the SES damping can be greatly improved. This has been verified by additional field tests on six GT generation units. Now these generators can be operated very well although the EAFs still cause voltage fluctuation.