In our plant, we have two frame 5GT's (12 MW each) and one H25 (25 MW) Hitachi Gas turbines. The Hitachi Gas turbine has FSRLLBIAS factor kept as 3% to restrict the GT to take sudden load. It is limited to take 4.2 MW maximum only. Why is this factor necessary? According to them it is kept to prevent sudden frequency drop. Is there any restriction on GE machines for the sudden load run up? What is the allowable sudden load run up in GE gas turbines?