Coordinated Control of Optimized SFCL and SMES for Improvement of Power System Transient Stability

It is well known that the Superconducting Magnetic Energy Storage (SMES) is effective to damp the power swing after the occurrence of faults. Nevertheless, if the SMES is also applied for transient stability improvement, a large power capacity of SMES is required. Additionally, the SMES is not able to absorb enough energy during faults since the bus voltage where the SMES is installed, drops considerably. To enhance the SMES control effect and transient stability, this paper proposes the coordinated control of the optimized resistive type superconducting fault current limiter (SFCL) and SMES. When the fault occurs, the SFCL rapidly suppresses the transient power swing by limiting the fault current. Subsequently, the SMES damps out the remaining power swing. The optimization problem of SFCL resistance and power controller parameters of SMES with optimal coil size is formulated based on an augmentation of transient stability margin and damping performance. Solving the problem by the particle swarm optimization, the optimal parameters of SFCL and SMES can be automatically obtained. Simulation study confirms the superior stabilizing effect of the coordinated SFCL and SMES over the individual device. The SFCL not only solves the voltage drop problem at the SMES bus, but also assists the SMES to stabilize the system. Besides, the MW and MJ capacities of the SMES operated with SFCL are significantly reduced.