A framework for dynamic security assessment of combined multi-terminal HVDC and AC grids

This paper discusses some challenges that dynamic security assessment and control will face due to the integration of multi-terminal high-voltage direct-current grids and the resulting interconnection of multiple asynchronous AC areas. A conceptual framework is outlined to address these challenges and ensure the security of the combined AC/DC system. The need for cooperation and exchange of information between the various transmission system operators is highlighted in order to take full advantage of the control flexibility of HVDC converters in post-contingency situations.