| 摘要 |
PURPOSE:To prevent production of excessive thermal stress, by a method where in, in a re-heat condensate type steam turbine, when warming-up of a casing is carried out before ventilation during the starting of cooling-down, an avoid ance condition based on a metal temperature is added to a casing warming-up starting condition. CONSTITUTION:A reheat condensate type steam turbine plant is provided with a boiler 1, high pressure, middle pressure, and low pressure turbines 5, 10, 12, and a condenser 13. During warming-up of a casing in the plant, when the metal temperature of a high pressure first stage rear inner wall is below a specified value x deg.C (usually about 150 deg.C) or less at the starting point of the starting of warming-up of a casing, warming-up of a casing is effected as usual. Meanwhile, when exceeding the x deg.C, the casing is completely prevented from being warmed-up until a boiler is ignited. On-off control is performed so that, when a high pressure first stage is decreased to lower than the x deg.C after igni tion, a warming-up valve 17 is opened with a specified opening, and the warm ing-up valve 17 is fully closed when increased to y deg.C (a set value 10-30 deg.C higher than x deg.C), warming-up of the casing is executed.
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