Two types of steam turbine for ultra-supercritical 660 MW units manufactured from Shanghai Steam Turbine Works

namely steam turbine with three cylinders and two exhaust outlets(type A) as well as steam turbine with four cylinders and four exhaust outlets(type B)

have been compared each other in aspects of the structure and size of teh steam turbine proper

the technical and economical indices

and the size of turbine house

etc..Results show that the steam turbine of type A has one LP cylinder less than that of steam turbine of type B

the manufacturing cost of steam turbine will decrease;the total heating surface area of two types is basically identical

the lateral size of condenser for steam turbine of type A is larger;under rated operating condition

the internal efficiency of steam turbine of type B is greater

and its thermal economic efficiency is better

but under low load

the efficiency of steam turbine type A is even higher;the civil engineering cost of steam turbine type B can be saved 9.22 million yuan compared with that of steam turbine type A.The opinions for type selection of steam turbines have been also recommented.