| 摘要 |
PURPOSE:To prevent the temperature of a steam turbine from abruptly varying in a speed governing method in which a nozzle shut-off valve is used to carry out the speed governing process of nozzle shut-off type and the speed governing process of throttling type, by closing all adjusting valves at the final stage after opening once any adjusting valves which have been closed at the preceding stage, when the adjusting valves are successively closed upon lowering of the load from the maximum load. CONSTITUTION:In a speed governing method of nozzle shut-off type in which adjusting valves respectively provided for more than three groups of first stage nozzles are individually controlled, when the load is lowered from a maximum load condition in which all valves are closed, more than one adjusting valves are at first closed, and then more than one remaining adjusting valves are closed. Thereafter, all adjusting valves opened at that time are controlled to be all closed simultaneously. With this arrangement, under the load condition in which above-mentioned adjusting valves that are closed at the third stage are positioned at the intermediate position, the adjusting valves closed at the first and second stages are started to be opened, and then in a low load side range all adjusting valves are closed. |
