SFCL Influence on Critical Clearing Time Improvement using Critical Trajectory Method

Transient stability analysis plays an essential role in the smart grid system, mainly due to the nonlinearity and uncertainty of the power system. The transient stability issue has been considered a tremendous challenge when the protection system must work quickly and accurately to isolate the fault. Critical Clearing Time (CCT) became an essential aspect for protection engineers to determine the maximum clearing time for the protection system to isolate the fault and maintain system stability. Moreover, to improve the system CCT value and give the protection system a long time to clear the fault, Superconducting Fault Current Limiter (SFCL) is utilized. The effectiveness of the proposed method is proven using a multi-machine IEEE 3-machine 9-bus system as a benchmark with Critical Trajectory methods, which have faster calculation and better accuracy than other methods. The simulation results show that CCT improvement using SFCL will depend on the installation location of SFCL and the fault point of the system. Thus, the optimal place for SFCL utilization is lines between bus 1 and bus 4, with an average CCT increase of 2%. SFCL utilization gives a longer time for the protection system to isolate the faults. As a result, the system can maintain the system stability after the fault period and improve overall system transient stability.