Grain-oriented silicon steel (GOFeSi) laminations are massively used as magnetic cores in electrical energy converters (motors and transformers). Edge burrs can appear during the manufacturing process and be at the origin of interlaminar faults (ILFs). In a recent paper, we described an efficient simulation method for GOFeSi laminations. This technique simultaneously solves the magnetic diffusion equation and a fractional differential equation for the material law. It produces excellent results across a large bandwidth of frequencies and is limited to only two parameters for the dynamic contribution. This study extends this method to predict the influence of interlaminar faults. We successfully reproduce experimental data for aligned ILFs and predict their impact in different working conditions. This work provides potential improvements in transformer reliability and defect detection.