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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

Edition date: 2009-03-09
In Force
Available languages: Spanish, English, French
Summary: IEC 60909-3:2009 is also available as IEC Standards+ 60909-3:2009 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.

IEC 60909-3:2009 specifies 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, i. e.:
- currents during two separate simultaneous line-to-earth short circuits in isolated neutral or resonant earthed neutral systems;
- partial short-circuit currents flowing through earth in case of single line-to-earth short circuit in solidly earthed or low-impedance earthed neutral systems.
The currents calculated by these procedures are used when determining induced voltages or touch or step voltages and rise of earth potential at a station (power station or substation) and the towers of overhead lines. Procedures are given for the calculation of reduction factors of overhead lines with one or two earth wires. This edition constitutes a technical revision. The main changes with respect to the previous edition are:
- New procedures are introduced for the calculation of reduction factors of the sheaths or shields and in addition the current distribution through earth and the sheaths or shields of three-core cables or of three single-core cables with metallic non-magnetic sheaths or shields earthed at both ends;
- The information for the calculation of the reduction factor of overhead lines with earth wires are corrected and given in the new Clause 7;
- A new Clause 8 is introduced for the calculation of current distribution and reduction factor of three-core cables with metallic sheath or shield earthed at both ends;
- The new Annexes C and D provide examples for the calculation of reduction factors and current distribution in case of cables with metallic sheath and shield earthed at both ends.

This publication is to be read in conjunction with IEC 60909-0:2001.

IEC 60909-3:2009 est disponible sous forme de IEC Standards+ 60909-3:2009 qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.

IEC 60909-3:2009 spécifie les procédures applicables au calcul des valeurs présumées des courants de court-circuit lors d'un court-circuit déséquilibré dans les réseaux triphasés à haute tension à courant alternatif fonctionnant à une fréquence nominale de 50 Hz ou 60 Hz, c'est-à-dire:
- les courants durant deux courts-circuits monophasés simultanés séparés à la terre dans les réseaux à neutre isolé ou mis à la terre par une bobine d'extinction;
- les courants de court-circuit partiels s'écoulant à travers la terre, dans le cas d'un seul court-circuit monophasé à la terre dans les réseaux à neutre mis à la terre directement ou par une faible impédance.
Les courants calculés suivant ces procédures sont utilisés pour la détermination des tensions induites ou des tensions de contact ou de pas, et de la montée du potentiel de terre d'un poste (groupe de production, poste), ainsi que les pylônes des lignes aériennes. Des procédures de calcul des facteurs de réduction des lignes aériennes avec un ou deux câbles de garde sont fournies. Cette édition constitue une révision technique. Les modifications principales par rapport à l'édition précédente sont les suivantes:
- De nouvelles procédures sont fournies pour le calcul des facteurs de réduction des gaines ou des écrans, ainsi que pour la répartition du courant par la terre et les gaines ou les écrans des câbles à trois conducteurs ou de trois câbles monoconducteurs avec gaines ou écrans non magnétiques métalliques mis à la terre à chaque extrémité;
- Les informations pour le calcul du facteur de réduction pour lignes aériennes avec câbles de garde sont corrigées et fournies en un nouvel Article 7;
- Un nouvel Article 8 est introduit pour le calcul de la répartition du courant et du facteur de réduction des câbles avec gaine ou écran métallique, mis à la terre à chaque extrémité;
- Les nouvelles Annexes C et D donnent des exemples pour le calcul des facteurs de réduction et de la répartition du courant dans le cas de câbles avec gaine ou écran métallique, mis à la terre à chaque extrémité.
Le contenu du corrigendum de septembre 2013 a été pris en considération dans cet exemplaire.

Cette publication doit être lue conjointement avec la IEC 60909-0:2001.
ICS: 29.240.20-Power transmission and distribution lines, 17.220.01-Electricity. Magnetism. General aspects
CTN: TC 73 - 1261

Standards Cancellations

Anula a IEC 60909-3:2003

Correcciones Normas

Es corregida por IEC 60909-3:2009/COR1:2013

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