LOW SPEED OPERATING DEVICE FOR STAND-BY WATER SUPPLYING PUMP TURBINE

PURPOSE:To enable a pump turbine to wait for its operation at the number of revolution substantially lower than the number of revolution of a water supplying pump during its operation, reduce a power for a water supplying pump, and restrict a temperature of discharged gas of the water supplying pump turbine to a value less than a limit value by a method wherein when the number of revolution of the water supplying pump waiting is decreased, a driving steam temperature of the water supplying pump turbine is decreased. CONSTITUTION:When a water supplying pump 13 starts a waiting operation through a recirculating operation in the case of performing a low output operation of a power generating plant as means for decreasing a driving steam temperature, water is fed to a temperature reducer 30 arranged in a low pressure steam pipe 19 and a temperature of the water supplying pump turbine driving steam is decreased. Water feeding for the temperature reducing unit 30 is adjusted by a method wherein a degree of opening of a water supplying adjustor valve 32 arranged in a water supplying pipe 31 is adjusted by a signal of a temperature adjusting unit 33. Although a driving steam of a water supplying pump turbine 18 is supplied by steam of a low pressure steam pipe 19, means is provided for changing-over the water supplying pump turbine driving steam during waiting of the water supplying operation to steam of a steam pipe 37 from a discharged gas of a high pressure turbine with a low temperature.