IEC 60826:2017

FOREWORD
1 Scope
2 Normative references
3 Terms, definitions, symbols and abbreviations
4 General
5 General design criteria
6 Loadings
7 Strength of components and limit states
Annex A (informative) - Technical information - Strength
        of line components
Annex B (informative) - Formulas of curves and
        figures
Annex C (informative) - Atmospheric icing
Annex D (informative) - Application of statistical
        distribution functions to load and strength of
        overhead lines
Annex E (informative) - Effect of span variation on
        load-strength relationship - Calculation of span
        use factor
Annex F (normative) - Conductor tension limits
Annex G (informative) - Methods of calculation for
        wind speed up effects due to local topography
Bibliography

IEC 60826:2017 specifies the loading and strength requirements of overhead lines derived from reliability-based design principles. These requirements apply to lines 45 kV and above, but can also be applied to lines with a lower nominal voltage.
This document also provides a framework for the preparation of national standards dealing with overhead transmission lines, using reliability concepts and employing probabilistic or semi-probabilistic methods. These national standards will need to establish the local climatic data for the use and application of this standard, in addition to other data that are country- specific.
Although the design criteria in this standard apply to new lines, many concepts can be used to address the design and reliability requirements for refurbishment, upgrading and uprating of existing lines.
This document does not cover the detailed design of line components such as supports, foundations, conductors or insulators strings.
This fourth edition cancels and replaces the third edition published in 2003. It constitutes a technical revision.
The main technical changes with regard to the previous edition are as follows:
This standard has been further simplified by removing many informative annexes and theoretical details that can now be found in CIGRE Technical Brochure 178 and referred to as needed in the text of the standard. Many revisions have also been made that reflect the users experience in the application of this standard, together with information about amplification of wind speed due to escarpments. The annexes dealing with icing data have also been updated using new work by CIGRE.
Key words: Overhead lines, Overhead transmission lines, reliability, energy