Abstract
The requirement for a stable startup, a stable shutdown and for a wide range power changing is urgent in the recent thermal power plants. In this paper, a new control system fulfilling the requirement is discussed and proposed for steam turbine which is one of the most important parts in a thermal power plant.
First, dynamic characteristics of a turbine are analyzed and the problems which must be taken into consideration at synthesis of a control system are clarified. Especially, non-linear characteristics of the revolutional speed and the output power in the case of combinational manipulation of several control valves during turbine startup and shutdown as well as the wide range output power change are discussed and clarified. The results of the investigation of dynamics are reflected upon the development of a new control system (governor).
Finally, the digital turbine governor with the following features is proposed.
(1) A wide coverage of control functions including turbine startup, shutdown and a wide range output power changing.
(2) Coexistence of flexibility and standardization of control functions by the introduction of microcomputers.
(3) High reliability by a redundant system.
The expected performance was actually confirmed by the operation of the newly developed turbine governor at an actual thermal power plant.
