Short circuit currents in diesel generator fed isolated networks

Low voltage isolated networks fed by diesel generators are sometimes not sufficiently modelled by the methods used in standard IEC 60909-0, Short-circuit currents in three-phase a.c. systems, Calculation of currents. This is especially the case if the minimum short-circuit current needs to be calculated. Checking the compliance with fault clearing times and testing of selectivity of protection depends on this kind of short-circuit current. In this article the short- circuit currents calculated according to standard IEC 60909-0 are compared to those calculated by a transient simulation for a real-world example. It is verified if the results obtained by calculations according to the standard yield accurate and safe results.