This paper presents the results obtained of the simulation and development of a protection library for MATLAB/Simulink, including the models of different functions that will be included in future schemes of protection, and digitals relays multifunction construction. First of all, a methodology exposing how the library was constructed, including the different models, and their communication architecture are presented. Secondly, a case of study in a Steel Arc-furnace, with a new adaptive protection coordination scheme using models of the library is proposed. Finally, the results of the simulation are exposed and a description of how this case of study can be used for comparison of protection schemes is described.