Real-time transient stability detection in the power system with high penetration of DFIG-based wind farms using transient energy function

•Transient instability detection using the potential energy boundary surface.•Introducing the new PEBS-based index for real-time applications of power systems.•Instability detection without directly calculating the unstable equilibrium point.•The new PEBS-based index requires only post-fault data of the power system. In this paper, a new approach for real-time transient instability detection (TID) is presented. The purpose of presenting this approach is to have the lowest computational load and the highest accuracy and speed and to be suitable for real-time applications. The main idea is TID without directly calculating the unstable equilibrium point (UEP). In fact, transient instability is detected only by identifying the characteristics of the UEP and the kinetic energy function along with the potential energy boundary surface (PEBS) function. A new and standard single machine infinite bus system with high penetration of wind farms is used for simulation. First, dynamic modeling of various components of doubly fed induction generator (DFIG) and synchronous generator are described. Then, a model for the grid-connected DFIG is developed and a new PEBS-based index (NPI) for TID is presented. The NPI requires only post-fault data and can be applied as a general tool to any power system with any change in topology and operating conditions. Also, the impact of increasing the penetration of wind power, changing the operating conditions of the power system, different fault locations, and the power system strength on the transient stability is investigated. The simulation results show the effectiveness of the proposed approach for TID in a shorter time.