Technique Research Of Fault Detection And Diagnosis For Water-Turbine Governor Control System

As the vital control device in the hydraulic power plant, stability of the water-turbine speed governor is a key contribution to the security and stability of generator set, even the power system. There are lots of advances on the reliability of speed governor, but some faults occur sometimes such as hair grip of main control valve, servomotor offset, sensor's null shift and frequency signal break. In order to reduce the influence of these faults of speed governor, a new method for fault detecting and diagnosing of the control system of water-turbine generator set is presented in the paper, based on the generator set dynamical model combining the modern diagnosis techniques.According to many relative literatures, author analyzed and compared the common used fault diagnosis algorithms. Firstly, the dynamical model of the water-turbine generator control system was formed, and based on the model the author studied the fault modules of the control system. Then the faults of electro hydraulic servo system and sensor were transformed to resolvable models.Secondly, the author presented diagnosis algorithms, based on the fault filtering method and general dedicated Kalman filtering method, to diagnose faults of electro hydraulic servo system and faults of sensors. By observing the residual error between the outputs of filters and the corresponding outputs of actual system, abundant fault information was obtained, and all kinds of faults can be identified and isolated.Lastly, the designed fault diagnosis units for electro hydraulic servo system and sensor of water-turbine speed governor were simulated in PC. The simulating outputs indicated that the two fault diagnosis units could diagnose most faults of the water-turbine generator control system, and the presented faults diagnosis algorithm advanced the fault diagnosis technique for the speed governor control system of hydraulic power plant, and taken an important role to warrant the security and reliability of operation of the water-turbine generator set.