The operation and planning of power systems require extensive use of simulations and corresponding models. The emergence of new equipment and system configurations raises the need for new models and simulation approaches. This report is part of the HVDC-WISE project and deals with modelling approaches with three different perspectives: providing models for the next steps of the project; preparing the exchange of standardized models of HVDC equipment; preparing models of power electronic converters for a promising simulation method (dynamic phasors).