Generalized dynamic transient model for MTDC networks covering multiple topologies and contingencies

• Concise and versatile formulation for multi-Terminal HVDC grids. • Flexibility to accommodate HVDC grids of various topologies and typologies. • Suitable for integration into multi-machine RMS stability simulation tools. • Complete software tool for simulation of multi-Terminal HVDC grids. • Automatic initialization from an AC/DC power flow solution. This paper proposes a versatile and modular Multi-Terminal High Voltage Direct Current (MTDC) network model with a compact matrix formulation. There will be a growing deployment of MTDC grids, necessitating the development of novel tools and models for their analysis and simulation. The first contribution of the paper is the proposal of a new MTDC network model using graph theory. The model preserves the dynamics of the grid and is flexible to adapt to different topologies and sizes. The second contribution is the implementation of the proposed MTDC model in an integrated software framework for the dynamic simulation, which incorporates an automatic flat-start initialization from an AC/DC power flow. The tool is developed in Matlab/Simulink and it includes the possibility to simulate various types of contingencies including different types of short-circuits, line clearances and converter outages, both for monopolar and bipolar DC networks. This tool is designed for time domain simulation and small-signal analysis of systems, including MTDC networks, with the objective of studying the dynamics of novel converter models and control strategies. The results demonstrate the functionalities of the proposed MTDC network model and simulation tool, highlighting the importance of network dynamics in simulations with power electronic converters.