IEC TR 60909-4:2000

FOREWORD
1 General
      1.1 Scope and object
      1.2 Reference documents
      1.3 Definitions, symbols and indices, and equations
2 Positive-sequence, negative-sequence and zero-sequence
      impedance's of electrical equipment
      2.1 Overhead lines, cables and short-circuit
             limiting reactors
      2.2 Transformers
      2.3 Generators and power-station units
3 Calculation of short-circuit currents in a low-voltage
      system Un = 400 V
      3.1 Problem
      3.2 Determination of the positive-sequence
             impedance's
             3.2.1 Network feeder
             3.2.2 Transformers
             3.2.3 Lines (cables and overhead lines)
      3.3 Determination of the zero-sequence impedance's
             3.3.1 Transformers
             3.3.2 Lines (cables and overhead lines)
      3.4 Calculation of Ik and ip for three-phase short
             circuits
             3.4.1 Short-circuit location F1
             3.4.2 Short-circuit location F2
             3.4.3 Short-circuit location F3
      3.5 Calculation of Ikl and ip1 for line-to-earth
             short circuits
             3.5.1 Short-circuit location F1
             3.5.2 Short-circuit location F2
             3.5.3 Short-circuit location F3
      3.6 Collection of results
4 Calculation of three-phase short-circuit currents in
      a medium-voltage system - influence of motors
      4.1 Problem
      4.2 Complex calculation with absolute quantities
      4.3 Calculation with short-circuit reactances of
             electrical equipment
      4.4 Calculation with per-unit quantities
      4.5 Calculation with the superposition method
5 Calculation of three-phase short-circuit currents for
      a power station unit and the auxiliary network
      5.1 Problem
      5.2 Short-circuit impedance's of electrical
             equipment
             5.2.1 Network feeder
             5.2.2 Power-station unit
             5.2.3 Auxiliary transformers
             5.2.4 Low-voltage transformers 2,5 MVA and
                      1,6 MVA
             5.2.5 Asynchronous motors
      5.3 Calculation of short-circuit currents
             5.3.1 Short-circuit location F1
             5.3.2 Short-circuit location F2
             5.3.3 Short-circuit location F3
             5.3.4 Short-circuit location F4
             5.3.5 Short-circuit location F5
6 Test network for the calculation of short-circuit
      currents with digital programs in accordance with
      IEC 60909-0
      6.1 General
      6.2 High-voltage test network 380 kV/110 kV/30 kV
             6.2.1 Network topology and data
             6.2.2 Short-circuit impedance's of electrical
                      equipment
      6.3 Results
             6.3.1 Three-phase short-circuit currents
             6.3.2 Line-to-earth short-circuit currents

Intended to give help for the application of IEC 60909-0 for the calculation of short-circuit currents in 50 Hz or 60 Hz three-phase a.c. systems. It does not include additional requirements but does give support for the modelling of electrical equipment in the positive-sequence, the negative-sequence and the zero-sequence system and the practical execution of calculations in a low-voltage system, a medium-voltage system with asynchronous motors and a power-station unit with its auxiliary network feeding a large number of medium-voltage asynchronous motors and low-voltage motor groups.