Technical possibility and advisability of involving a T-250 cogeneration power unit into control of frequency and power in a power system

Studies carried out on a model of a T-250 power unit used as part of a computer-based training simulator are presented. The adequacy of the adopted model is estimated, and the power unit operating modes are analyzed in which the requirements of selective primary and automatic secondary control of frequency can be satisfied. Changing the flowrate of steam extractions from the turbine by producing inputs to the control valves in the bypass of the group of high-pressure steam lines and varying the supply of steam to the high-pressure steam lines and to the feedwater pump’s turbine drive are considered as control inputs for changing the power unit load along with commonly adopted variations of boiler load (with producing control input to the boiler power controller) and turbine load (with producing input to the power controller, which works out commands to the turbine control valves). The need of using combined control is also confirmed.