Operating experience for three-cylinder 700 MW steam turbine

摘要

In the view of stable power supply, high flexibility and high reliability are requisite conditions of the large steam turbine. Furthermore, turbines of an improved efficiency are required to protect global environment.Increase in steam temperature is an important factor in the improvement of turbine efficiency. And reduction of production cost is another important factor in recent years. A turbine must be a compact size even with large capacity.To meet these requirements, we developed a compact three-casing type 700 MW large capacity steam turbine which has a higher performance compared with conventional four-casing type turbine.This turbine was made for Reihoku Thermal Power Plant. The steam condition of the turbine is 24.1 Mpa (246 atg), 566/566°C. The turbine is a three-casing tandem compound type with titanium 40-inch last stage buckets. The rotational speed is 3600 rpm. TheHP and IP sections are built in a single casing using the counter flow arrangement to make the turbine compact.The turbine trial run, adjustment and test was completed successfully, and presently the turbine is operated commercially.This paper describes the structure of the steam turbine at the Reihoku Thermal Power Plant and its operating experience during the test operation.