Abstract: For long time the operation mode of 300MW steam turbine of Yunnan Huadian Kunming Power Generation Corporation Limited was below rated load. Using experiment method the sliding pressure operation curve for the best steam pressure was found out, and the relation between opening of steam turbine governing valves and the largest thermal efficiency was obtained. The application of sequence valve controlling for steam turbine governing valves tremendously decreases the throttling loss of single valve operation, and increases the thermal efficiency of steam turbine.

Key words: steam turbine governing valve, control parameter, reasonable steam distribution, optimization control, thermal efficiency