TURBINE ROLLING
TURBINE ROLLING OBJECTIVE OF TURBINE ROLLING:- To bring the unit on load and raised on rated output within optimum time but also without under stress on the turbine components. Warming up and startup of the turbine during various steam condition of or turbine metal temperature condition are given by the manufacturer in the form of few startup curves. TYPE OF UNIT STARTUP:- A unit start up described on the basic of turbine metal temperature as given (1) Cold startup :- HPT metal temperature is less then 150°C. Shut down time greater than 5 days rolling steam pressure 40 kg/cm² rolling steam temperature 350 °C. Soaking time 1 to 1.5 hours Load gradient 3 mw/min. (2) Warm startup:- HPT metal temperature is between 150°C to 350°C. Shut down time greater than 48 hours. rolling steam pressure 60 kg/cm² rolling steam temperature 400 °C. Soaking time half hours Load gradient 5 mw/min. (3) Hot startup:- HPT metal temperat