https://centralesupelec.hal.science/hal-03465507Lourenço, LuísLuísLourençoPolytechnic School of the University of São Paulo (Brazil) - USP - Universidade de São Paulo = University of São PauloL2S - Laboratoire des signaux et systèmes - CentraleSupélec - Université Paris-Saclay - CNRS - Centre National de la Recherche ScientifiquePerez, FilipeFilipePerezLactec InstituteIovine, AlessioAlessioIovineL2S - Laboratoire des signaux et systèmes - CentraleSupélec - Université Paris-Saclay - CNRS - Centre National de la Recherche ScientifiqueDamm, GilneyGilneyDammUniversité Gustave EiffelMonaro, RenatoRenatoMonaroPolytechnic School of the University of São Paulo (Brazil) - USP - Universidade de São Paulo = University of São PauloSalles, MaurícioMaurícioSallesPolytechnic School of the University of São Paulo (Brazil) - USP - Universidade de São Paulo = University of São PauloStability Analysis of Grid-Forming MMC-HVDC Transmission Connected to Legacy Power SystemsHAL CCSD2021POWER SYSTEM STABILITYVOLTAGE SOURCE CONVERTERSMODULAR MULTILEVEL CONVERTERGRIDFORMING CONVERTERFUTURE POWER SYSTEMHIGH-VOLTAGE DIRECT-CURRENT - HVDCENERGY FUNCTION STABILITY ANALYSISSYSTEME NON LINEAIRE[SPI.NRJ] Engineering Sciences [physics]/Electric power[MATH.MATH-OC] Mathematics [math]/Optimization and Control [math.OC]Iovine, Alessio2021-12-15 10:45:262023-03-24 14:53:242022-01-03 09:30:57enJournal articleshttps://centralesupelec.hal.science/hal-03465507/document10.3390/en14238017application/pdf1The 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.