• # PD IEC TR 60909-1:2002

Current The latest, up-to-date edition.

Short-circuit currents in three-phase a.c. systems Factors for the calculation of short-circuit currents according to IEC 60909-0

Available format(s):  Hardcopy, PDF Language(s):  English

Published date:  31-07-2002

Publisher:  British Standards Institution

FOREWORD
1 General
1.1 Scope and object
1.2 Reference documents
1.3 Application of the factors
1.3.1 Factor c
1.3.2 Factors K[G] and K[S] of K[SO]
1.3.3 Factors K[G,S], K[T,S] or K[G,SO], K[T,SO]
1.3.4 Factor K[T]
1.3.5 Factors [kappa]
1.3.6 Factors [mu], [lambda] and [q]
1.3.7 Factors [m] and [n]
1.3.8 Contribution of asynchronous motors to the
initial symmetrical short-circuit current
1.4 Symbols, subscripts and superscripts
1.4.1 Symbols
1.4.2 Subscripts
1.4.3 Superscripts
2 Factors used in IEC 60909-0
2.1 Voltage factor c for the equivalent voltage source
at the short-circuit location
2.1.1 General
2.1.2 Calculation methods
2.1.3 Equivalent voltage source at the short-circuit
location and voltage factor c
2.1.4 A simple model illustrating the meaning of the
voltage factor c
2.2 Impedance-correction factors when calculating the
short-circuit impedances of generators, unit
transformers and power-station units
2.2.1 General
2.2.2 Correction factor K[G]
2.2.3 Correction factors for power station units with
2.2.4 Correction factors for power station units without
2.2.5 Influence of the impedance correction factor for
power-station units when calculating short-circuit
currents in meshed networks and maximum
short-circuit currents at worst-case load flow
2.3 Impedance correction factor K[T] when calculating the
short-circuit impedances of network transformers
2.3.1 General
2.3.2 Example for a network transformer S[rT] = 300 MVA
2.3.3 Statistical examination of 150 network transformers
2.3.4 Impedance correction factors for network
transformers in meshed networks
2.4 Factor [kappa] for the calculation of the peak short-circuit
current
2.4.1 General
2.4.2 Factor [kappa] in series R-L-circuits
2.4.3 Factor [kappa] of parallel R-L-circuits
2.4.4 Calculation of the peak short-circuit current i[P]
in meshed networks
2.4.5 Example for the calculation of [kappa] and i[P] in
meshed networks
2.5 Factor [mu] for the calculation of the symmetrical
short-circuit breaking current
2.5.1 General
2.5.2 Basic concept
2.5.3 Calculation of the symmetrical short-circuit breaking
current I[b] with the factor [mu]
2.6 Factor [lambda] (lambda[max], lambda[min]) for the calculation
2.6.1 General
2.6.2 Influence of iron saturation
2.7 Factor [q] for the calculation of the short-circuit breaking
current of asynchronous motors
2.7.1 General
2.7.2 Derivation of factor [q]
2.7.3 Short-circuit breaking currents in the case of
unbalanced short circuits
2.8 Factors [m] and [n] for the calculation of the Joule integral
or the thermal equivalent short-circuit current
2.8.1 General
2.8.2 Time-dependent three-phase short-circuit current
2.8.3 Factor [m]
2.8.4 Factor [n]
2.8.5 Factor [n] in IEC 60909-0, figure 22
2.9 Statement of the contribution of asynchronous motors or groups
of asynchronous motors (equivalent motors) to the initial
symmetrical short-circuit current
2.9.1 General
2.9.2 Short circuit at the terminals of asynchronous motors
2.9.3 Partial short-circuit currents of asynchronous motors
fed through transformers
2.9.4 Sum of partial short-circuit currents of several
groups of asynchronous motors fed through several
transformers
Bibliography
Figures and Tables

## Abstract - (Show below) - (Hide below)

Applies to short-circuit currents in three-phase a.c. systems. This technical report aims at showing the origin and the application, as far as necessary, of the factors used to meet the demands of technical precision and simplicity when calculating short-circuit currents according to IEC 60909-0.

## Scope - (Show below) - (Hide below)

This part of IEC 60909 is a technical report applicable to short-circuit currents in three-phase a.c. systems. This technical report aims at showing the origin and the application, as far as necessary, of the factors used to meet the demands of technical precision and simplicity when calculating short-circuit currents according to IEC 60909-0.

Thus this technical report is an addition to IEC 60909-0. It does not, however, change the basis for the standardized calculation procedure given in IEC 60909-0.

NOTE References are given in some cases to offer additional help, not to change the procedure laid down in the standard.

## General Product Information - (Show below) - (Hide below)

 Committee W/- Development Note Supersedes BS PD7639-1(1994). (08/2005) Document Type Standard ISBN Pages Published Publisher British Standards Institution Status Current Supersedes

## International Equivalents – Equivalent Standard(s) & Relationship - (Show below) - (Hide below)

 Equivalent Standard(s) Relationship IEC TR 60909-1:2002 Identical

## Standards Referencing This Book - (Show below) - (Hide below)

 IEC 60038:2009 IEC standard voltages IEC 60909-3:2009 Short-circuit currents in three-phase AC systems - Part 3: Currents during two separate simultaneous line-to-earth short circuits and partial short-circuit currents flowing through earth IEC 60909-3 : 3.0 SHORT-CIRCUIT CURRENTS IN THREE-PHASE AC SYSTEMS - PART 3: CURRENTS DURING TWO SEPARATE SIMULTANEOUS LINE-TO-EARTH SHORT CIRCUITS AND PARTIAL SHORT-CIRCUIT CURRENTS FLOWING THROUGH EARTH IEC 60909-0:2016 Short-circuit currents in three-phase a.c. systems - Part 0: Calculation of currents IEC 60865-1:2011 Short-circuit currents - Calculation of effects - Part 1: Definitions and calculation methods IEC 60909:1988 Short-circuit current calculation in three-phase a.c. systems

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