Short-circuit current contribution of converter interfaced wind turbines and the impact on system protection

Traditional short-circuit modeling techniques and the associated models existing in commercially available packages are not accurate enough and do not accurately represent the behavior of converter interfaced renewable energy resources during short-circuit events. To address those issues, detailed EMT-type, time domain models of Type III and Type IV wind turbines have been developed as part of this work. Those models can be used to achieve an improved understanding of the way in which these devices affect system protection and of improved short-circuit models for system studies. The potential impact of renewable energy resources on relay misoperation and protection coordination is discussed, given that depending on the type of the wind turbines and the associated controls, the short circuit current contribution of a wind park might be the same for different locations of the fault. Finally, presently available modeling techniques of renewables in frequency domain are presented and compared. Their disadvantages are discussed along with an approach for improved modeling.