IEC 60781:1989
Withdrawn
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Application guide for calculation of short-circuit currents in low-voltage radial systems
Hardcopy , PDF , PDF 3 Users , PDF 5 Users , PDF 9 Users
31-12-2021
English - French
30-01-1989
FOREWORD
PREFACE
Clause
1 Scope
2 Object
3 General calculation methods and calculation assumptions
4 Definitions
4.1 Short circuit
4.2 Far-from-generator short circuit
4.3 Short-circuit current
4.4 Prospective (available) short-circuit current
4.5 Initial symmetrical short-circuit current
4.6 Peak short-circuit current
4.7 Symmetrical short-circuit breaking current
4.8 Steady-state short-circuit current
4.9 Nominal system voltage
4.10 Short-circuit impedances of electrical equipment
4.11 Short-circuit impedances at the short-circuit location
4.12 Voltage source
4.13 Equivalent voltage source
4.14 Voltage factor c
5 Symbols, subscripts and superscripts
5.1 Symbols
5.2 Subscripts
5.3 Superscripts
6 Short-circuit types
7 Calculation methods and assumptions
7.1 Symmetrical components
7.2 Equivalent voltage source at short-circuit location
7.3 Conditions for disregarding the influence of motors
8 Short-circuit impedances of electrical equipment
8.1 High-voltage network feeders
8.2 Transformers
8.3 Overhead lines and cables
8.4 Other impedance elements
8.5 Conversion of impedances
9 Calculation of short-circuit currents
9.1 Balanced three-phase short-circuit current
9.2 Line-to-line short-circuit current without earth
connection
9.3 Line-to-earth short-circuit current
10 Example of short-circuit current calculations using forms
10.1 General procedure
10.2 Explanations for using the calculation forms
11 Example for a housing installation
11.1 Network diagram
11.2 Data of electrical equipment
11.3 Special remarks
FORMS
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