IEC 60099-5:2018

Overview

IEC 60099-5:2018 - "Surge arresters - Part 5: Selection and application recommendations" provides guidance for the selection, application and coordination of surge arresters used on three‑phase systems with nominal voltages above 1 kV. This third edition (2018) replaces the 2013 edition and incorporates a technical revision that aligns arrester selection practice with the new surge arrester classification introduced in IEC 60099‑4:2014.

Key topics and requirements

• Scope of arrester types: Gapless metal‑oxide arresters (IEC 60099‑4), combined series/parallel gapped arresters rated ≤ 52 kV (IEC 60099‑6), and metal‑oxide arresters with external series gap for overhead lines (EGLA, IEC 60099‑8). Annex J discusses older SiC gapped arresters.
• Insulation coordination: Procedures and application practices for line and substation insulation coordination, including selection workflows and coordination studies.
• Residual voltage: Emphasis on residual voltage as a primary selection parameter; typical maximum residual voltages are provided in Annex F.
• New classification guidance: Expanded comparison between the former line discharge classes and the newer charge/energy‑based classification; methods to estimate equivalent charges and energies are included (Annexes H and I).
• Application‑specific guidance: Selection for line surge arresters (LSA), cable protection, distribution systems, UHV, capacitor switching, transformer neutrals, phase‑to‑phase arrangements and parallel arrester applications.
• Modelling & diagnostics: Recommended arrester models for impulse and insulation studies (Annex C) and diagnostic/monitoring methods for MO arresters in service (Annex D).
• Asset management: Practical guidance on procurement data, commissioning, maintenance, monitoring, end‑of‑life, disposal and recycling (Annexes E, D and main text).

Practical applications and intended users

IEC 60099‑5 is essential for:

• Utility and transmission/distribution engineers specifying and procuring surge arresters
• Protection and insulation coordination engineers performing surge and switching studies
• Substation designers and consulting engineers defining arrester ratings and residual voltage limits
• Asset managers and maintenance teams implementing diagnostic programs and end‑of‑life strategies
• Manufacturers and testing laboratories preparing product data and compliance guidance

Use cases include selecting arresters for new installations, verifying coordination for system upgrades, estimating arrester cumulative energies during line switching, and defining maintenance/monitoring procedures.

Related standards

• IEC 60099‑4 - Metal‑oxide surge arresters (classification and test methods; 2014 revision relevant)
• IEC 60099‑6 - Surge arresters with series/parallel gapped structures (rated ≤ 52 kV)
• IEC 60099‑8 - Externally gapped line arresters (EGLA)

Keywords: selection and application of surge arrestors, surge arresters, nominal voltages above 1 kV, residual voltage, insulation coordination, IEC 60099‑5:2018.