Jens Fortmann describes the deduction of models for the grid integration of variable speed wind
turbines and the reactive power control design of wind plants. The modeling part is intended as
background to understand the theory capabilities and limitations of the generic doubly fed
generator and full converter wind turbine models described in the IEC 61400-27-1 and as 2nd
generation WECC models that are used as standard library models of wind turbines for grid
simulation software. Focus of the reactive power control part is a deduction of the origin and
theory behind the reactive current requirements during faults found in almost all modern grid
codes. Based on this analysis the design of a reactive power control system for wind turbines
and wind plants is deduced that can provide static and dynamic capabilities to ensure a stable
voltage and reactive power control for future grids without remaining synchronous generation.
