What is Turbine cold start up?

cold start up of a steam turbine has to be done after a rather long period of shut down - when turbine case and chest temperature are fallen down dramatically. turbine constructor heating ramps mast be followed in order to avoid thermal stresses on the metal of turbine case , valve case and rotor to avoid also height differential expansion between rotor and case that could lead to contact between case and rotor because of the different thermal inertia of the two parts.when the heating is complited the turbine can be started checking closely the differntial expansion recorders.when at speed the unit can be sincronyzed (usually at 3000 rpm) and then loaded according to the related load ramp.(megawatts\ minute)