| 摘要 |
PURPOSE:To shorten the time of starting of a steam turbine provided with a combined reheating valve unit, by gradually opening the minor valve of a reheating stop valve unit to control the minor flow rate and thereafter opening an intercept valve in such a manner that the quantity of reheated steam does not change sharply. CONSTITUTION:The difference between a governor set value 51 and a rotational frequency signal 63 found out by a speed detector 62 is entered into limiters 52, 53, 54 for steam valves. The lifting characteristics of the valves are determined so that in a main steam line a speed deviation signal from a governor and the flow rate at a steam regulating valve 56 have a rectilinear relationship with each other and in a reheated steam line the deviation signal and the sum of the flow rate at a reheating stop valve 58 and that at an intercept valve 60 have a rectilinear relationship with each other, thereby improving the controllability of the quantity of steam at the time when the lift position signals of the steam valves are sent out to start a turbine from th state of turbine by-passing operation. After the starting of the turbine, a minor valve built in the reheating stop valve 58 is gradually opened to heighten the rotation of the turbine. The intercept valve 60 is then closed to the position for the minor-valve flow rate to put the turbine into rated operation. |
