Steam power plant with pressure-fired boiler

Claim 1

Apparatus for regulating a steam power plant of the type including a pressure-fired boiler supplying steam to a turbine group, a charging group for the boiler operating at high pressure ratios, said charging group including an axial flow compressor having adjustable blading and which is driven by a gas turbine for supplying combustion air to the boiler and a speed governor, said gas turbine being driven by combustion gas discharged from the boiler such that the heat content thereof is substantially completely consumed in the turbine and the power delivered by it to the compressor, and a governor in the live steam feed line from the boiler to the steam turbine group, said regulating apparatus comprising first means responsive to a variable control signal produced by said live-steam governor in accordance with a variation in plant load for regulating fuel flow to said boiler, second means responsive to said control signal for regulating the heat content of the combustion gas flowing to said gas turbine and for regulating said speed governor, third means responsive to said control signal for adjusting the compressor blading, and means effecting a sequentially functional relationship between said second and third means such that in the case of a decrease in plant load and a resultant increase in live steam pressure, first the speed of said charging group is decreased to and held at a predetermined value by a reduction in the heat content of the combustion gas flowing to said gas turbine followed by an adjustment of the compressor blading in a direction to reduce its air throughput with the speed of said charging group being held constant at said decreased predetermined value, whereas in the case of an increase in plant load and a resultant decrease in live-steam pressure, first said compressor blading is adjusted in a direction to increase its air throughput followed by an increase in the heat content of the combustion gas flowing to said gas turbine and hence an increase in speed of said charging group.