NBN EN 60909-3 : 2010

FOREWORD
1 Scope
2 Normative reference
3 Terms and definitions
4 Symbols
5 Currents during two separate simultaneous line-to-earth
  short circuits
  5.1 Calculation method
      5.1.1 Initial symmetrical short-circuit current
      5.1.2 Peak short-circuit current, symmetrical
            short-circuit breaking current and steady-state
            short-circuit current
      5.1.3 Distribution of line-to-earth short-circuit
            currents during two separate simultaneous
            line-to-earth short circuits
6 Partial short-circuit currents flowing through earth in
  the case of an unbalanced short circuit
  6.1 Calculation method
      6.1.1 General
      6.1.2 Line-to-earth short circuit in a station
      6.1.3 Line-to-earth short circuit far outside a station
      6.1.4 Line-to-earth short circuit in the vicinity of a
            station
      6.1.5 Reduction factor for overhead lines and cables
Annex A (informative) Example for the calculation of two
                      separate simultaneous line-to-earth
                      short-circuit currents
Annex B (informative) Examples for the calculation of partial
                      short-circuit currents through earth
Annex ZA (normative) Normative references to international
                      publications with their corresponding
                      European publications

Describes 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.