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The provision of system support services by converter-interfaced generation (CIG), which were previously assigned to the conventional synchronous generation, is a challenging task extremely necessary for the stable operation and control of modern power systems. The most promising solution in this direction is the application of grid-forming control strategies for the CIG. This paper proposes a CIG' control system based on a freely configurable structure of a virtual synchronous generator (FC-VSG). In this control system, different levels of the inverter control are implemented in parallel, and in order to improve the transient performance and damping properties of CIG, the inertial and governor response are coupled at the inner control level, a voltage regulator is added at the outer control level, as well as the combined use of a virtual damper winding and power system stabilizer is applied. Such solutions made it possible not only to mimic the behavior of a conventional rotating machines, but also to significantly improve the transients' dynamics. To show the effectiveness of the proposed control system, time-domain simulations and experimental case studies have been performed. In addition, the qualitative and quantitative assessment of the dynamic response of the FC-VSG in comparison with both the conventional voltage-controlled VSG structure and the dynamics of a practical synchronous machine have been carried out. [ABSTRACT FROM AUTHOR]

One of the problems associated with the integration of renewable energy sources is reducing the total inertia of the electric power system. By substituting the traditional synchronous generators to wind turbines connected to a network via power electronics devices the system the inertia constant is sharply reduced. In addition, the inertia of the system changes over time due to the wind turbine power change. Systems with lower inertia in the serious faults incident loses its stability easier. The question of the reduction of energy system inertia influence on the out-of-step mode parameters is not answered yet. Authors created a grid test model using software-hardware hybrid simulation tool HRTSim. The several experiments to determine the influence of type 4 wind turbine on the parameters of the out-of-step mode is realized. The oscillograms confirming the influence of the wind turbine on the parameters of the out-of-step mode are obtained. Problems of the influence of changes in the inertia of the power system during the integration of type 4 wind turbines on the parameters of the out-of-step mode are considered. The international experience in this field is analysed. The results of the analysis confirmed the insufficient study of this field and the almost complete lack of information about this in the grid codes of foreign countries. The experiments confirmed the theoretical expectation: the higher inertia induction stroke starts later, and the frequency slip is decreased. [ABSTRACT FROM AUTHOR]