The need for accurate dynamic models of wind plants for grid planning studies is increasing as penetration of wind power increases. Furthermore, the ultimate objective is a moving target. As wind penetration increases, grid codes are evolving to include more rigorous performance requirements, which in turn lead to more sophisticated control functions and dynamic characteristics of wind turbines and wind plants. Since the equipment and models are continuously evolving, there is an ongoing need to update and validate wind plant models. This paper discusses field tests results from operating wind turbine generators and wind plants, as well as comparisons with simulation results using dynamic models.