Abstract: In an attempt to improve the accuracy of stability calculation for power system and the scientificity of test unit’s production operation by power grid dispatch, control parameters testing and modelling for the turbine governing system of a 300 MW mixed flow hydropower unit were performed as a case study. On the basis of the hydraulic machinery features of the test unit and the actual control logic of the governing system, the electrical control, hydraulic system and prime mover of the governing system were modeled using MatLab/Simulink. The nonlinearity of the governing system caused by dead time, limit, delay and nonlinear functions and the convenience of simulation were both considered in the modelling. In particular, for the prime mover, the model of power system analysis software package (PSASP) and the user-defined model were established respectively. The model parameters were measured and identified. The model of PSASP and the user-defined model were comparatively analyzed and the results showed that the user-defined model parameters could better reflect the dynamic response characteristics of the test unit. The research finding provides references for the improvement and development of power system stability calculation for hydropower units.

Key words: turbine governing system, actuator, parameter testing, modeling, nonlinear characteristic, stability calculation for power system