Research on Transient Characteristics of Doubly Fed Wind Power Generator under Symmetrical Short-circuit Fault Considering Grid-side Converter Control

When grid fault occurs, the doubly fed induction generator short-circuit currents are very complex due to the interaction between the doubly fed induction generator and the grid. As the capacity of wind power generation increases, it has become vital to analyze and evaluate the doubly fed induction generator stator/rotor short-circuit currents correctly so that the generator's low-voltage ride-through can be realized, as well as the analysis and calculation of fault electrical variables. In this article, a doubly fed induction generator fault transient model fully considering grid-side converter control and the doubly fed induction generator terminal phase jump is established first. On this basis, the transient expressions of doubly fed induction generator rotor and stator currents under a grid threephase symmetrical fault are derived. The mechanism in which the short-circuit current is affected by the doubly fed induction generator terminal voltage phase jump and grid-side converter control is then revealed. Thus, a more accurate description of the doubly fed induction generator fault transient process under grid fault is achieved. Time-domain simulation and dynamic experiments both verify that the expression of the short-circuit current obtained according to the proposed method is correct.