Impact of Renewable Energy Sources on the German Power System

In Germany due to the continuous high expansion of the intermittent power supply capabilities of wind turbines and photovoltaic systems, the operational modes of thermal generation units will be influenced essentially until 2020 and beyond. With the renewable energy sources (e.g. wind power (WP) and photovoltaic (PV)) in power system increase, the conventional power plants on line will be replaced by WP and PV. Thus, the sources of conventional reserve available to the system will be reduced and fewer conventional plants will be available online to share the regulation burden. Therefore the acceleration time constant is reduced if some of the conventional power plant generators with inertia (masses) are disconnected and replaced by the intermittent generators while the total nominal power value of the whole system remains constant. With the reduction of inertia not only the frequency deviation after disturbances will increase substantially but also more oscillation occurs which causes reduction in system stability. Therefore different scenarios of Renewable Energy sources will be presented and for the investigation of the system stability influenced by the primary control of the remaining conventional power plants the following mathematical methods are useful and have been used nonlinear dynamic simulation andl inear eigenvalue calculation. The models were created using MATLAB / Simulink software.