Characteristics of Short-circuit Current of Wind Turbine Driven DFIG and Its Impacts on Grid-connected Distribution Network

Most research on the short-circuit current contributed by wind turbine driven doubly-fed induction generator(DFIG) focuses on the non-grid-connected DFIG and grid-connected DFIG with the short-circuit point located at the generator's terminal.When the DFIG is connected to a distribution network,the short-circuit current of DFIG may be affected by the characteristics of the distribution network,the location of the short-circuit point and other factors.First,based on the Park model of induction motor,a detailed mathematical derivation for the transient characteristics of DFIG in the external fault is conducted and analyzed.The composition of the short-circuit current of DFIG and an approximate expression of the shortcircuit current are proposed.Then,the effect factors to short-circuit current of DFIG are analyzed.Finally,the simulation shows the correctness of the analysis.