Stability region of a wind power system under low-voltage ride-through constraint

With the increasing penetration of renewable generation, the problem of transient stability has changed and new unstable scenarios have emerged. Consequently, the foundations of direct methods for stability assessment must be revisited. Unstable modes triggered by disconnection of renewable generators are commonly related to violation of operating limits and not to the problem of synchronism among synchronous generators. In this paper, the concept of constrained stability region is used to study transient stability of a power system with a wind generator subject to the low-voltage ride-through (LVRT) curve constraint. The constrained stability region is studied by means of an associated auxiliary system that has its unconstrained stability region equal to the constrained stability region of the original system.