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We are in the middle of an important transition of electrical power systems. Conventional power plants are being replaced by renewable energy sources, which are mainly connected to the grid via power electronic converters. Whenever a conventional, synchronous generator (SG) based, power plant is decommissioned some inertia, frequency and voltage control mechanism are lost. Conventional plant is being replaced by converter-based generation, creating critical challenges in power systems. A main interest is how these systems will operate with the known level of effectiveness and reliability. Nowadays, the converter-based generation that is connected to the grid is grid-feeding. They can operate sufficiently under the presumption that they are connected to a strong AC network. New control techniques for converters, for example grid-forming strategies, are being developed to address these challenges and to offer ancillary services that until now have been provided by SGs. In this paper, a gridforming system and control strategy is explained and developed. Its impact on the wider electrical power system will be discussed and a grid forming grid forming control strategy will be presented. The grid forming system is tested on a IEEE sample 9 bus network that is 80% and 100% converter based. The system behavior will be presented subject to load increase/decrease and post fault behavior. [ABSTRACT FROM AUTHOR]

In this paper, a virtual synchronous machine (VSM) controller of grid-connected power converters for rms studies in DIgSILENT PowerFactory is presented. This control structure emulates the dynamic behavior of a synchronous machine (SM) in order to enable a larger penetration of converter-connected generation in the grid. However, compared to the SM, the converter should be able to limit the current flowing through the converter to the maximum allowed current during transients. Therefore, a current limitation control is also implemented. Simulation results are presented which verify the performance of the VSM by comparison to the dynamic response of an equally sized SM during disturbances. The functionality of the current limitation controller is illustrated by simulation of a three-phase to ground fault in the grid, not far from the converter. [ABSTRACT FROM AUTHOR]

We are in the middle of an important transition of electrical power systems. Conventional power plants are being replaced by renewable energy sources, which are mainly connected to the grid via power electronic converters. Whenever a conventional, synchronous generator (SG) based, power plant is decommissioned some inertia, frequency and voltage control mechanism are lost. Conventional plant is being replaced by converter-based generation, creating critical challenges in power systems. A main interest is how these systems will operate with the known level of effectiveness and reliability. Nowadays, the converter-based generation that is connected to the grid is grid-feeding. They can operate sufficiently under the presumption that they are connected to a strong AC network. New control techniques for converters, for example grid-forming strategies, are being developed to address these challenges and to offer ancillary services that until now have been provided by SGs. In this paper, a gridforming system and control strategy is explained and developed. Its impact on the wider electrical power system will be discussed and a grid forming grid forming control strategy will be presented. The grid forming system is tested on a IEEE sample 9 bus network that is 80% and 100% converter based. The system behavior will be presented subject to load increase/decrease and post fault behavior. [ABSTRACT FROM AUTHOR]

In this paper, a virtual synchronous machine (VSM) controller of grid-connected power converters for rms studies in DIgSILENT PowerFactory is presented. This control structure emulates the dynamic behavior of a synchronous machine (SM) in order to enable a larger penetration of converter-connected generation in the grid. However, compared to the SM, the converter should be able to limit the current flowing through the converter to the maximum allowed current during transients. Therefore, a current limitation control is also implemented. Simulation results are presented which verify the performance of the VSM by comparison to the dynamic response of an equally sized SM during disturbances. The functionality of the current limitation controller is illustrated by simulation of a three-phase to ground fault in the grid, not far from the converter. [ABSTRACT FROM AUTHOR]