## 1 Introduction  
In the global effort to achieve the ambitious targets for decarbonisation of the energy system, at a national and global level, wind energy plays a significant role now and a major one in the future. Thus, the European Union (EU) aims to move to 100% clean energy by 2050 as an important step in achieving climate neutrality, the energy sector being responsible for more than 75% of greenhouse gas emissions (GHG) at the European level, according to the European Green Deal [1]. This goal can be achieved by using renewable energy sources, a key role being granted to increasing wind production by improving wind energy systems, especially installed offshore. In all decarbonisation scenarios, which consider the high-level implementation of renewable energy systems, it is emphasized that the main source of electricity generation will be wind power by 2050 [1, 2] with a share of over 36% of the total [3, 4]. Thus, wind energy had a total installed capacity of 743 GW at the end of 2020 [5], with an increase to over 6000 GW foreseen by 2050 [4], as wind power remains an efficient and affordable technology of producing clean electricity in a safe and sustainable way. Energy management considering the variability of renewable energy sources and the reliability of networks and systems facing utility grid outages remains a challenge for energy systems with a high share of renewables [6, 7, 8]. The wind energy sector is gaining more and more popularity among researchers, developers and investors. They have paid attention to the behaviour of onshore and offshore wind systems and their components in different operating conditions. Their optimal design and modelling are permanent challenges in ensuring the high energy performance of wind systems, operating under variable wind conditions. Therefore, the dynamic behaviour of wind turbines is of significant interest as it influences significantly the conversion system functional performance, output power, and reliability. The dynamic modelling of wind turbines in order to identify and control their behaviour or their functional optimization has drawn the attention of many researchers in recent decades. The research in this field is addressing either the dynamics of the entire wind turbine/farm or the dynamic modelling of a component of the wind conversion system: wind rotor, speed increase, or electric generator. Different dynamic modelling approaches are presented in the literature, while the simulation is mainly performed with the MATLAB-Simulink software package. [PERSON] et al. present in [9] the modelling of a floating wind turbine under a broad spectrum of sea and wind conditions. The dynamic model is compared with the FAST reference model (fatigue, aerodynamics, structures, and turbulence), a reference software for modelling offshore wind turbines, the errors between the two models being reported as being below two percent. A similar concept is presented in [10] where the hydrodynamic performance of the floating foundation of an offshore wind turbine is analysed based on Reynolds-Averaged Navier-Stokes simulations. The FAST dynamic model allows the performance investigation of the floating platform under operational and storm conditions. A rigid multibody dynamic model for a floating offshore wind turbine and its dynamic responses are presented in [11]. The authors use the Euler-Lagrange equations for system motion, while the dynamic response under four load cases is validated against the FAST model. The dynamic of the onshore wind systems is addressed as well in the literature, referring mainly to general theoretical models, based on customised models that can be developed. For instance, [PERSON] and [PERSON] present in [12] a dynamic model that includes aerodynamic, mechanical, and electrical components of a turbine operating at a constant wind speed. The model is simulated in four case studies to prove its validity. Equivalent models of wind farms operating at constant wind speed are proposed in [13].