Experimental Study on Large Turbine HP-Valve’s Excitation Fault Caused by Steam’s Unsteady Flow and its Economic Solution

In order to stabilize the uncertainty of large-scale new energy power’s random fluctuation in the grid, there is an increasing number of large thermal power generating unit needing to do deep variable load operation. However, the pattern of steam inlet on turbine’s part load has a very significant impact on the unit operation condition of safety, stability and economy. In this paper the HP-valve’s body vibration fault of large steam turbines caused by unsteady steam flow under partial arc admission operating at part of their full load is researched, and an economic solution based on analysis and diagnosis of fault mechanism is provided by designing of complex HP-valve opening sequence rules. This solution solves the safety problem of valve vibration and avoids the economic loss by using full arc admission or replacing the valve body equipment directly, which is of great effective and practical verified by units’s actual operating experiment. As a result, it demonstrates that the optimization of HP-valve iadmission mode can not only change the stress state of high pressure rotor and prevent its vibration caused by the force of unbalanced flow to improve the shafting stability of the unit when running with variable load, but also can improve the steam instability and solve the resulting vibration problem in HP-valve. And it is of great engineering practical value to improve high-power thermal power unit depth secure efficient load operation.