Transient Phenomena in Francis Turbine Power Plants: Interaction with the Power Network.

Models of hydraulic components based on impedance method have been implemented in a software called “SIMSEN”. This software allows the simultaneous solution of the electrical, hydraulic, mechanic and control equations ensuring a proper interaction between these four parts of a system. Using this tool, in this paper, the transient behavior of an islanded power network is investigated. This network comprises a 2 Francis turbines hydroelectric power station of 172 MW, a nuclear power station of 1300 MW and a consumer load. The nuclear power station modeling takes into account the rotating masses and stiffness, the rotational speed regulators, a first order steam turbine model and the generator. Two disturbances are simulated using SIMSEN: the hydroelectric power plant switch off and the load acceptance and rejection. The simulation results show how the power is balanced during such transients. This approach allows for the analysis of control command parameters of an islanded power network.