Research on Method of the Flow Passage Condition Monitoring and Diagnosis for Steam Turbine

Abstract

Abstract Monitoring and diagnosis of the steam turbine flow passage is the most important premise to achieve the power plant condition maintenance. The existing characteristic flow area of steam turbine changes with main steam flow and can not accurately reflect the flow passage state of steam turbine. In order to reflect the state change in turbine passage accurately, the characteristic flow area of steam turbine stage should be investigated in the same main steam flow. Because main steam flow on-line measuring method accuracy is deficient, a new method based on the exhaust pressure of IP cylinder as character parameter of main steam flow is proposed, and a correction method which takes the impact of the heat regenerative system on main steam flow into consideration is presented. Meanwhile, in the diagnostic process, the measuring result is strongly influenced by the system inevitable measuring error which directly affects the deviation between the characteristic flow area and its standard. Thus confidence intervals of characteristic flow area is given to eliminate the system errors. Finally, the actual diagnostic example in the article indicates the practicability of the method. It can be used to diagnose the flow passage of steam turbine and provide reliable basis to find out the steam turbine potential.