This presentation will feature covert ABB Fault Current Limiter (FCL) application engineering for Is-limiters. We will explain the fault current limiter technology by using the well-known ABB FCL Is-limiter. The FCL technology will be introduced, how it clears a short-circuit fault current compared to a standard circuit breaker, and the major components of an FCL. The theory of the application engineering process and the calculation of the tripping value for an FCL will be introduced. Based on an actual customer project, it will be shown how ETAP has facilitated the complex FCL application engineering, and examples will be provided of how the real tripping value for a fault current limiter is determined. The session will conclude with an overview of how etap can already be used today for an FCL application engineering and what will be enhanced in the future.