TEMPERATURE CONTROL OF A STEAM TURBINE STEAM TO MINIMIZE THERMAL STRESS

摘要

A steam turbine system having a steam chest coupled in operating relationship to a steam turbine includes apparatus for controlled heating of the steam chest to reduce thermal stresses. A throttle valve is connected in a steam flow path between a steam source and the steam chest for regulating the flow of steam over a predetermined range of steam flow rates. A temperature sensor is coupled to the steam chest for providing signals indicative of the temperature of the steam chest. A steam leak-off line coupled to the steam chest includes a flow control valve for regulating the flow of steam from the steam chest through the leak-off line, and a controller is coupled in a controlling relationship to the throttle valve and the flow control valve for controlling the flow of steam into and out of the steam chest to effect a controlled warming of the steam chest. The controller is connected to receive the signals from the temperature sensor and is responsive to the signals for controlling warming of the steam chest.