DIN EN 60909-3 VDE 0102-3:2010-08

This part of IEC 60909 specifies procedures for calculation of the prospective short-circuit currents with an unbalanced short circuit in high-voltage three-phase a.c. systems operating at nominal frequency 50 Hz or 60 Hz, these are currents during two separate simultaneous line-to-earth short circuits in isolated neutral or resonant earthed neutral systems as well as partial short-circuit currents flowing through earth in case of single line-to-earth short circuit in solidly earthed or low-impedance earthed neutral systems.