| 摘要 |
PURPOSE:To stop a tubine easily with low cost by operating an air exhauster upon provision of load interruption command to the turbine thereby discharging the air in the conduit casing and lifting the water level in the discharge path to such level as a portion of runner will be submerged. CONSTITUTION:Upon provision of a load interruption command to a turbine under full-open or partial-open condition of guide vane 6, the stop valve 31 of an air exhauster 30 is opened to function a vacuum pump 33. At the sametime, a closing command is provided to the guide vane 6 to perform gradual closing operation. The rotation speed of turbine will exceed over rated one and increase. Here, the air in the conduit casing 10 between the runner 1 and the water face of the discharge path 16 is discharged before the rotation of turbine will reach the runaway speed. Consequently, the water level in the discharge path 16 is lifted to such level that a portion of runner 1 will be submerged thus to suppress the increase of rotation speed of the turbine. |
