The scope of this guide is the definition of load models for various conventional and emerging elements in the generation, transmission, distribution and customer sectors at all voltage levels. This includes guidance for developing load models, identifying load model parameters, and utilizing measurement data for load model development at various voltage levels. It also includes modelling practices for emerging elements such as power electronics connected elements, electrical vehicles and charging stations, better utilization of Information and Communication Technology (ICT) infrastructures in load model development, and dynamics associated with customer involvement.