A Sensor-less Jam Fault Detection Method for Electro-hydraulic Executive Device of Steam Turbine

The jam fault of electro-hydraulic servo valve in steam turbine EHC (electro-hydraulic control) system sadly affects the security of unit. For normal detection method, due to the inaccuracy of non-fault characteristic parameter of object as well as the issue of the reliability and accuracy of sensor itself, the sensitivity and reliability of result can´t be guaranteed. This paper presents a sensor-less jam fault detection method based on electro-reflection to feed back the fault information directly. The mathematical model analysis and simulation study indicated it has high detecting sensitivity and reliability. The physical comparison research was carried out based on jam fault simulation device. The results validated its feasibility and consistency with the simulation one. On base of this, a new electro-hydraulic converter with function of jam fault tolerant was constructed