PURPOSE: To shorten the start time of a turbine by obtaining the value of thermal stress generated to a low pressure turbine from the low pressure turbine inlet part metal temperature, and controlling a heating steam pressure control valve so that this value does not exceed the specified value to the specific life.
CONSTITUTION: The low pressure turbine inlet part metal temperature 13 is detected and taken into a thermal stress computing element 26. The specific life consumption of a low pressure turbine 5 is computed from thermal stress generated to the low pressure turbine 5, and the thermal stress value is determined from a life cycle. This value is compared with the thermal stress limit value of a thermal stress limiter 28 by a thermal stress comparator 27. The compared result is sent as a thermal stress ratio to a thermal stress ratio - heating steam pressure change rate setter 25, and the optimum heating steam pressure change rate is determined according to the operating state of the turbine. Turbine load from a load detector 21 is sent as the heating steam set pressure to a heating steam pressure setter 23. The heating steam pressure, a change rate setting signal and the signal of an actual heating steam pressure detector 14 are compared by a heating steam pressure comparing part 19 to compute the deviation, and a heating steam pressure control valve 8 is controlled in response to this signal.
NISHINOMIYA TAKUJI
HIRONO MASAMITSU
IGARASHI KINGO
HITACHI ENG CO LTD
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