Voltage-Based Current Limitation Strategy to Preserve Grid-Forming Properties Under Severe Grid Disturbances

Abstract

Grid-forming (GFM) converters are a promising solution to enable large scale integration of renewable energy sources into the power system. However, due to the intrinsic voltage-source behaviour of GFM converters, current limitation during large grid disturbances is challenging. This article presents a novel limitation strategy that preserves the GFM properties of the converter and at the same time effectively limits the converter current to the desired value. Through the limitation of the converter's internal voltage, stable operation even during faults and in case of large frequency disturbances in the grid is achieved. Experimental results show the effectiveness of the proposed current limitation strategy in case of various grid disturbances.

Keywords

• Current limitation
• grid-forming converter
• grid-connected converter
• transient stability
• unbalanced faults
• virtual inertia