The subject of a cogeneration plant modeling has already been discussed in the past, but mostly from the thermal and energy point of view. There are several aspects to be considered for assuring that the plant will operate satisfactoraly. Furthermore the increasing number of energy producers poses more and more attention to these types of planes and to their regulation mode. Among these aspects, particular care is devoted in this paper to the modeling and setting-up of gas turbine regulators, also because it is not generally such a trivial work to adapt existing software for large power systems＇ dynamic analysis to the requirements of combined-cycle power plants. On the basis of the specialized literature, a detailed model for the regulator of a gas turbine unit is adapted, which includes speed, acceleration and temperature controls as well as inlet guide vanes＇ control. The proposed regulator is tested on a realistic industrial power plant with particular attention to parallel and isolated operation.