Impacts of large scale wind power on power system transient stability

Wind power generation changes the load flow, the swing modes and transient stability of the integrated power system. The characteristic of power transient stability is well studied for large scale wind power integration in this paper. Different wind power generator models, including fixed speed induction generator (FSIG) and double-fed induction generator (DFIG), are considered in the analysis, as well as different penetration levels, faults locations and faults clearing time. By using extended equal area criterion (EEAC), it was revealed that large scale wind power integration may change the unstable mode (UM), namely the pattern of dividing all generators into the critical cluster (CC) and the remaining one (RC), the times of the swing for an unstable case, or the change rate of the swing stability margin for a stable case. If some traditional synchronous generators within the CC are replaced with wind power generators, power system transient stability degree can be either decreased or increased. Similarly, these phenomena might also appear if the replacement occurs in the RC. Based on EEAC, this paper presents such cases with simulations, and conducts theoretical and quantitative analyses to explain the mechanisms behind. The impacts of large scale wind power on system power transient stability can be mainly ascribed to the change of the equivalent generalized inertia of the CC and that of the RC, and their equivalent accelerating power.