| 摘要 |
PROBLEM TO BE SOLVED: To keep a constant seal steam pressure in turbine trip and parallel-off of a power generator, even when a turbine inlet pressure changes in a steam turbine of variable pressure operation, when turbine gland seal steam is used by decompressing turbine inlet steam.SOLUTION: A gland seal device includes a seal steam branch passage 29 branched from an upstream side of a main steam stop valve 25 and a steam governing valve 27, and guiding seal steam to gland portions 9, 11, a seal steam pressure control valve 31 controlling a seal steam pressure to the gland portions 9, 11, and a seal steam control device 47 controlling an opening of the seal steam pressure control valve 31. The seal steam control device 47 has a target control portion 57 for keeping the seal steam pressure to the gland portions at a constant target pressure, and a transient control portion 49 for variably controlling the opening of the seal steam pressure control valve 31 to an opening corresponding to the main steam pressure in at least one of a turbin trip and parallel-off of a power generator. |
