IEC 61400-27-2 specifies procedures for validation of electrical simulation models for wind turbines and wind power plants, intended to be used in power system and grid stability analyses. The validation procedures are based on the tests specified in IEC 61400-21. The validation procedures are applicable to the generic models specified in IEC 61400-27-1 and other fundamental frequency wind power plant models and wind turbine models. The validation procedures for wind turbine models focus on tests for response to voltage dips, voltage swells and reference point changes. Those validation procedures refer to the wind turbine terminals. The validation procedures for wind power plant models focus on tests for response to reference point changes as well as voltage dips and voltage swells. Those validation procedures refer to the point of connection of the wind power plant. The validation procedures specified in IEC 61400-27-2 are based on comparisons between test results and simulations, but they are independent of choice of software simulation tool.