SHORT-CIRCUIT CURRENTS IN THREE-PHASE A.C SYSTEMS - PART 4: EXAMPLES FOR THE CALCULATION OF SHORT-CIRCUIT CURRENTS
International Electrotechnical Committee
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.
| Document Type | Standard |
| Status | Current |
| Publisher | International Electrotechnical Committee |
| Committee | IEC TC 73 |
| Supersedes |
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