Comparison between Symmetrical Short Circuit Current Contribution of Droop-Based Grid Forming Converter and Synchronous Generator

Future power systems may use fewer Synchronous Generators due to the growing use of inverter-connected renewables such as wind and solar photovoltaic systems. As a result, the power systems' dynamic properties can alter in previously unnoticed ways. Specifically, the rising penetration of such renewables may significantly impact short circuit current contribution in future power systems. As a result, this may substantially affect how protective relays function and how they are configured. This is because short circuit currents injected into the grid from inverter-connected renewables have distinct properties. Grid Following converters' short circuit contribution has been extensively studied in the past; however, the short circuit contribution of Grid Forming converters has yet to be fully explored in the corpus of current studies. Thus, the main objective of this paper is to investigate the transient short circuit current contribution of Grid Forming converters utilizing Droop-based converter technology—under a three-phase symmetrical fault and compare it to that of a traditional Synchronous Generator. An analysis is conducted on the phase currents, positive sequence active and reactive currents, and the positive sequence current of the Grid Forming converter and Synchronous Generator. The simulation studies are carried out on a single-machine infinite bus test system and DIgSILENT Power Factory software is used to obtain the findings in this research.