MT 10 - TC 37/MT 10

IEC 60099-5:2018 is available as IEC 60099-5:2018 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60099-5:2018 provides information, guidance, and recommendations for the selection and application of surge arresters to be used in three-phase systems with nominal voltages above 1 kV. It applies to gapless metal-oxide surge arresters as defined in IEC 60099-4, to surge arresters containing both series and parallel gapped structure – rated 52 kV and less as defined in IEC 60099-6 and metal-oxide surge arresters with external series gap for overhead transmission and distribution lines (EGLA) as defined in IEC 60099-8. In Annex J, some aspects regarding the old type of SiC gapped arresters are discussed. Surge arrester residual voltage is a major parameter to which most users have paid a lot of attention to when selecting the type and rating. Typical maximum residual voltages are given in Annex F. It is likely, however, that for some systems, or in some countries, the requirements on system reliability and design are sufficiently uniform, so that the recommendations of the present standard may lead to the definition of narrow ranges of arresters. The user of surge arresters will, in that case, not be required to apply the whole process introduced here to any new installation and the selection of characteristics resulting from prior practice may be continued. Annexes H and I present comparisons and calculations between old line discharge classification and new charge classification. This third edition cancels and replaces the second edition published in 2013. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition regarding the new surge arrester classification introduced in IEC 60099-4:2014:
a) Expanded discussion of comparison between the old and new classification and how to calculate or estimate the corresponding charge for different stresses.
b) New annexes dealing with:
- Comparison between line discharge classes and charge classification
- Estimation of arrester cumulative charges and energies during line switching
Keywords: selection and application of surge arrestors, nominal voltages above 1 kV

IEC 60099-5:2013 is not a mandatory standard but provides information, guidance, and recommendations for the selection and application of surge arresters to be used in three-phase systems with nominal voltages above 1 kV. It applies to gapless metal-oxide surge arresters as defined in IEC 60099-4, to surge arresters containing both series and parallel gapped structure - rated 52 kV and less as defined in IEC 60099-6 and metal-oxide surge arresters with external series gap for overhead transmission and distribution lines (EGLA) as defined in IEC 60099-8. In Annex H, some aspects regarding the old type of SiC gapped arresters are discussed. This second edition cancels and replaces the first edition published in 1996 and its amendment 1 published in 1999. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- Expanded discussion of different types of arresters and their application, including additions of discussion on transmission of line arresters, arresters for shunt capacitor switching arresters for series capacitor protection, application of arresters between phases connecting arresters in parallel;
- Addition of section on asset management, including: managing surge arresters in the power grid, arrester maintenance, significantly expanded discussion of performance diagnostic tools, end-of-life considerations;
- New annexes dealing with: arrester modelling for system studies, example of data needed for specifying arresters. Key words: selection and application of surge arrestors, nominal voltages above 1 kV