TURBIN SHAFT VIBRATION PREVENTING APPARATUS IN STEAM TURBIN PLANT

摘要

PURPOSE:To automatically prevent the vibration of a turbin shaft at the time of a sudden reduction of influx of steam into the turbin by raising pressure in a condenser after the pressure in the condenser is monitored to verify that it is not above the upper limit when the change in the turbin shaft vibration is large. CONSTITUTION:The turbin steam flow rate signal 17 is inputted to a turbin steam flow rate monitoring device 20 in a turbin shaft vibration preventing apparatus 13 which monitors rate and magnitude of change in the steam flow rate, and actuates a pressure control device 22 of a condenser when the specified flow rate change (a) and magnitude of change (b) are exceeded. In the pressure control device, when turbin shaft vibration does not exceed the rate of change (c) or vibration magnitude (d), and when the pressure in the condenser 5 which is inputted through a signal line 19 does not exceed the specified value, the pressure in the condenser 5 is raised by inputting an output from the turbin shaft vibration monitoring device 23, which receives a turbin shaft vibration signal 18, to decrease the delivery rate of a flow rate controller 14 of off-gas line through a signal line 25.