Transient Current Analysis Method of DFIG Voltage Dip Based on Crowbar Protection

A doubly fed induction generator (DFIG) may be switched off by its over current protection when a short circuit fault happens in the grid connected with it. Therefor, it is very important to analyze the influence of the short current on the low voltage ride-through (LVRT) of the DFIG quantitatively. The three phase symmetrical short-current linkage characteristics of DFIG have been analyzed. The transient current calculation method with voltage dip range has been given. Then the function of crowbar circuit for LVRT of a DFIG is taken into consideration, and a practical calculation method of transient current of the DFIG for three phase voltage dipping has been given. The comparation between calculation results and the test data taken from wind field prove the feasibility of transient response calculation method.