Dynamic models of wind farms for grid-integration studies

In The Netherlands offshore wind power is on the brink of implementation. Specific plans exist for two offshore wind farms of about 100 MW, located 12 and 25 km from the coast of the province of North Holland. The effects of the incorporation of 6000 MW offshore wind power in the Dutch high voltage grid are currently investigated. Until now only the steady state behaviour is considered, resulting in suggestions for grid reinforcement. This investigation will be comple- mented by a study on the dynamic interaction of wind power and grid. Tools for this investigation, viz. dynamic models of wind farms including all relevant electrical components, have recently been developed. This paper gives an overview of wind farm dynamic models and concentrates on their use in a case study. Special concern exists about wind farm behaviour during extreme wind speed changes and abnormal grid conditions (voltage and frequency dips); these may cause complete wind farms to shut down instantaneously. Assisting grid voltage and frequency control is also an issue. In a case study the models will be used to calculate the flicker contribution of a wind farm, simulate responses to grid faults and develop wind farm control.