Advanced control strategies for grid-following inverter fault response: Implementation and analysis in MATLAB for protection studies in medium voltage distribution networks

The growing integration of Inverter-Based Distributed Generation (IIDG) in distribution networks poses significant challenges for protection systems, as it alters the usual short-circuit patterns and impacts their effectiveness. International standards such as IEEE 1547-2018 and the German network code VDE-AR-N 410 for distribution networks, along with the IEEE 2800-2021 standard for transmission systems, have set criteria for the connection of IIDGs and their behavior under fault conditions, including the injection of reactive current and current limiting. These standards have driven the development of new control models for fault response: the conventional model, according to IEEE 1547-2018, requires IIDGs to inject only balanced positive sequence currents to provide voltage support to the network, while the advanced model, in accordance with VDE-AR-N 410 and IEEE 2800-2021, demands the injection of both positive and negative sequence currents to enhance voltage support during unbalanced faults. This article explores how these fault response models affect the efficiency of traditional protection schemes, including overcurrent and directional elements, and develops a methodology for modeling the inverter’s response to faults. This approach enables the replication and application of international standards for the design of new protection schemes, facilitating their adoption by researchers in the field.