Method and arrangement for controlling fuel supply for a gas turbine

It is described a method of controlling a supply of a fuel (105) to a combustor (101) of a gas turbine comprising a compressor upstream of the combustor, the method comprising: supplying the fuel (105) to the combustor (101); obtaining a property value of at least one physical property (PT8, PT7, Tinlet, THBOV) of air used for burning the fuel (105) in the combustor (101); estimating a heat input (HIengmodel) of the fuel (105) supplied to the combustor (101) based on the property value; measuring a Caloric Value (LCVmea) of the fuel (105) upstream of the combustor (101); adjusting the estimated heat input (HIengmodel) based on the measured Caloric Value (LCVmea); and controlling a fuel valve (103) regulating the supply of the fuel (105) to the combustor (101) based on the adjusted estimated heat input (HIexpected) and a demanded heat input (FFDEM).