Design and performance optimization of a magnetic based fault current limiter using BBO

Abstract

Magnetic fault current limiters (MFCLs) are taking on greater importance in the modern power system because of their ability to suppress excessive fault currents, while having no effect on normal operation. This paper proposes a simulation-based design and performance optimization of a magnetic-based fault current limiter by using biogeography-based optimization (BBO). A coupled electromagnetic-electrical model is developed to describe the nonlinear interaction between current, inductance, magnetic flux, core saturation, and magnetic biasing. The optimization is concentrated on the core geometry, length of the air gap, number of turns of the winding, and size of the magnetic element to ensure effective reduction of the fault current without violating voltage and thermal limits. Finite element analysis is used to study magnetic field distribution, saturation phenomenon, and temperature rise in normal and faulty conditions. Time-domain simulations are also performed for symmetrical and asymmetrical fault cases for transient performance evaluation. The optimized MFCL shows a great reduction of peak fault current and energy dissipation compared with the initial design, with negligible impact during normal operation. Sensitivity and parametric analyses validate the optimization design robustness, which shows that the proposed BBO-based optimization design framework is effective in improving MFCL performance in power system protection applications.