Assessing the risk of islanding for distribution connected type 4 wind energy converters

The integration of wind farms into distribution systems requires consideration of a number of protection and control issues. As with any distributed generation, wind farms (WFs) are required to meet the utility´s interconnection requirements, one of which is anti-islanding protection. This paper evaluates the islanding risk associated with a 15 MVA WF equipped with full converter, i.e. type 4, wind energy converters (WECs) connected to a rural distribution feeder. Using detailed wind farm and distribution system models, parametric studies were conducted for load and generation levels and different WF control modes. Results show that the intertie protection is able to successfully identify all islanding conditions. Considering the breadth of cases considered, it was concluded that local protections are sufficient to meet the anti-islanding requirement and a transfer-trip scheme is not necessary.