Composite Short-Circuit Ratio

CSCR. The equivalent system impedance seen by multiple inverter-based resources by creating a common medium voltage bus and tying all inverter-based resources of interest together at that common bus.

Last Updated:  November 29, 2025

Version:  1.0.0

Generated:  December 04, 2025

Definition in an Article

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Composite short circuit ratio (CSCR) estimates the equivalent system impedance seen by multiple inverter-based resources by creating a common medium voltage bus and tying all inverter-based resources of interest together at that common bus. The composite short circuit MVA at the common bus without current contribution from the inverter-based resources, $CSC_{MVA}$, is then calculated. CSCR can then be calculated as

$ CSCR = \frac{CSC_{MVA}}{MW_{VER}} $

where $MW_{VER}$ is the sum of the nominal power rating of all inverter-based resources considered. This method calculates an aggregate SCR for multiple inverter-based resources, rather than each resource like the conventional SCR approach.