Enhanced "Second Kick" methods for on-line dynamic security assessment

Time domain-based online power system dynamic security assessment (DSA) systems require a fast and reliable method to calculate the stability margin. B.C. Hydro's online DSA uses the Second Kick method which proves to be an elegant and reliable method for margin calculation. The Second Kick technique although simple in concept, in its original implementation requires the application of two artificial faults. It also requires a "snapshot" option in the simulation program to save the system conditions at a point for later retrieval. In this paper, two new Second Kick methods namely Kiana and Fast Second Kick are devised and compared to the original method in terms of implementation requirements and computational effort. The above three techniques have been tested on the large scale systems of B.C. Hydro and Hydro Quebec. The results show that all three methods predict the stability limits accurately. They also indicate that the Fast Second Kick method is twice as fast as the original method whereas the Kiana method takes three times longer than the original method. Both of the new techniques remove the requirement for a snapshot resulting in easier implementation.