A Positive Sequence Screening Tool to Identify Areas of Potential Inverter Instability in Inverter Dominated Systems.

An increase in percentage of inverter-based generation in large power systems causes a reduction in the available fault current, resulting in a reduction of traditional system strength. A tool developed by EPRI called the Grid Strength Assessment Tool (GSAT) calculates various system strength metrics from a steady state analysis of the network model. This paper will outline the challenges associated with low system strength in inverter-based systems, the difficulty determining potential instabilities, details of the GSAT tool and the metrics available including an advanced Short Circuit Strenght (SCS) metric. [ABSTRACT FROM AUTHOR]