Modelling and GB Grid Code Compliance Studies of Offshore Wind Farms with Doubly-Fed Induction Generators

The number and total capacity of large offshore wind farms connected to the GB power supply network is going to increase considerably in the next years. The Doubly-Fed Induction Generator seems to be the preferable technology for offshore wind farms at the moment, at least in the UK. Average time-invariant models are usually used for the representation of Doubly-Fed Induction Generators. The validity of the approach is investigated by comparing the steady state and dynamic behaviour of such a model with a time variant model of the frequency converter of the DFIG, where the power electronic switches are represented. The commercial software PSCAD/EMTDC is used. Consequently, the compliance of an offshore wind farm with DFIGs with the GB Grid Code is examined in respect to the strength of the power supply network at the PoC and the electrical distance to the PoC. Nomenclature DFIG PoC SCL VSI Doubly-Fed Induction Generator Point of Connection Short Circuit Level Voltage Source Inverter