Through comparison of thermal parameters

and their rate of change

as well as the rotor's stress

strain

and life expenditure in two different processes for shutting down steam terbine unit no.4 in one power plant

namely sliding-parameter shut-down and forced shut-down

the influence of two shut-down processes upon rotor's life expenditure of the steam turbine has been analysed in detail

pointing out that the forced shut-down affects more greatly the rotor's life and the safety of boiler

and it is not advocated to adopt.The results of analysis have important significance for reasonable operation of power plant

lengthening service-life of the units

and enhancing the economic benefit.