A wind power system is a sophisticated combination of components and sub-systems that have to be designed in an interdisciplinary and integrated manner. In addition, the size and complexity of wind turbines is increasing rapidly over time, as seen in Fig. 9 [27]. Wind energy technology itself also moved very fast towards new dimensions. At the end of 1982, a 55 kW wind turbine
with a 15m rotor diameter was state-of-the-art. Today, 5000kW turbines with a rotor diameter of around 126m are available from many manufacturers [3,29].