This article presents a methodology to evaluate protection schemes in grids with nonlinear loads. For this purpose, a protection library developed in MATLAB/Simulink is presented, which is complemented with a communications system and an electric arc furnace (EAF). Subsequently, an application example is shown, in which the protection system of a steel manufacturing industry is developed, considering the linear and nonlinear loads, and tested using the methodology compound of four stages: the definition of the protections, the settings, the fault analysis, and the hardware implementation.