%0 Journal Article %T Stability Analysis of Grid-Forming MMC-HVDC Transmission Connected to Legacy Power Systems %+ Polytechnic School of the University of São Paulo (Brazil) %+ Laboratoire des signaux et systèmes (L2S) %+ Lactec Institute %+ Université Gustave Eiffel %A Lourenço, Luís %A Perez, Filipe %A Iovine, Alessio %A Damm, Gilney %A Monaro, Renato %A Salles, Maurício %< avec comité de lecture %Z DOC00033964 %@ 1996-1073 %J Energies %I MDPI %V 14 %N 23 %P 25p %8 2021-01-01 %D 2021 %R 10.3390/en14238017 %K POWER SYSTEM STABILITY %K VOLTAGE SOURCE CONVERTERS %K MODULAR MULTILEVEL CONVERTER %K GRIDFORMING CONVERTER %K FUTURE POWER SYSTEM %K HIGH-VOLTAGE DIRECT-CURRENT - HVDC %K ENERGY FUNCTION STABILITY ANALYSIS %K SYSTEME NON LINEAIRE %Z Engineering Sciences [physics]/Electric power %Z Mathematics [math]/Optimization and Control [math.OC]Journal articles %X The power system is going through a change in its very foundations. More and more power converters are being integrated into the electric grid to interface renewable energy resources and in high-voltage direct-current (HVDC) transmission systems. This article presents a discussion on the stability of power systems when HVDC transmission systems based on modular multilevel converters (MMC) are connected in grid-forming (GFM) mode to the legacy power system using concepts of energy functions and Lyapunov stability theory and considering aspects of the interoperability between GFM converter technologies. As a base for the stability analysis, we review the main GFM converter technologies (droop and virtual synchronous machine), highlighting their differences. Then, we present a model using the center-of-inertia formulation for a multi-machine/multi-GFM converter power system representing a close future scenario of power systems where GFM converters might adopt different technologies. To illustrate the theoretical Lyapunov-based stability analysis, simulations performed in Matlab/Simulink showed the behavior of a 12-bus test system during a frequency disturbance that originated from the sudden connection of a load. To reflect the interoperability of different GFM technologies and the power system, scenarios with one single GFM technology and a scenario with mixed technologies were investigated. For the test system considered, the frequency response with fewer oscillations and a higher frequency nadir was obtained when all GFM converters were operated as VSMs that have a higher inertial response contribution. %G English %2 https://centralesupelec.hal.science/hal-03465507/document %2 https://centralesupelec.hal.science/hal-03465507/file/doc00033964.pdf %L hal-03465507 %U https://centralesupelec.hal.science/hal-03465507 %~ CNRS %~ SUP_LSS %~ INSMI %~ SUP_SYSTEMES %~ CENTRALESUPELEC %~ TDS-MACS %~ UNIV-PARIS-SACLAY %~ TEST-HALCNRS %~ UNIVERSITE-PARIS-SACLAY %~ GS-ENGINEERING %~ GS-COMPUTER-SCIENCE %~ UNIV-EIFFEL %~ U-EIFFEL