Grid code requirements concerning connection and operation of wind turbines in Germany

This paper discusses issues of German grid codes relating to wind turbines. With the high utilization of wind power a simultaneous loss of several thousand MW wind generation became a realistic scenario in the German power system. Therefore, the main requirements concern the fault ride through capability of wind turbines. Accordingly, disconnection of wind turbines and wind farms above 15 % nominal voltage at the grid connection nodes is not allowed. Besides, following network faults wind turbines have to supply a definite reactive current depending on the instantaneous voltage. Furthermore, they must return quickly to normal operation. The frequency range wind turbines have to tolerate is about 47.5-51.5 Hz. According to the wishes of German transmission grid operators, large wind farms have to be treated in the future like conventional power plants.