IEC 62271-103:2021

Overview

IEC 62271-103:2021 is an international standard that specifies requirements for high-voltage alternating current switches and switch-disconnectors designed for indoor and outdoor installations. These devices are applicable for rated voltages above 1 kV and up to including 52 kV, with rated frequencies ranging from 16⅔ Hz to 60 Hz. This standard addresses three-phase systems as well as single-pole switches integrated within three-phase systems.

The 2021 edition is a significant technical revision of the previous 2011 version, aligned with IEC 62271-1:2017 and IEC 62271-102:2018, incorporating clarifications and updated testing rules particularly relating to current interruption, restrike allowances, making and breaking tests, and vacuum integrity checks. It also includes a new informative annex to guide calculations relevant to earth fault current breaking currents.

This standard is essential for manufacturers, designers, and testing bodies focused on high-voltage switchgear, offering comprehensive criteria for designing, testing, and operating AC switches at medium voltage level.

Key Topics

• Scope and Application
  Covers three-phase and single-pole alternating current switches for rated voltages from 1 kV to 52 kV, addressing indoor and outdoor use cases.

• Rated Characteristics
  Defines rated voltage, insulation levels, continuous current, short-time withstand current, peak withstand current, and various specific breaking currents such as cable charging, line charging, earth fault, motor breaking, and more.

• Mechanical and Electrical Endurance
  Specifies classes of mechanical endurance (M1, M2) and electrical endurance (E1, E2, E3) to categorize the durability of switches under operational stress.

• Design and Construction Requirements
  Includes requirements on the use of liquids and gases for insulation and operation, earthing, auxiliary circuits, manual and stored energy operations, locking devices, position indication, enclosure protection, creepage distances, fire hazard prevention, electromagnetic compatibility, corrosion resistance, and tightness for gas, vacuum, and liquid systems.

• Testing and Verification
  Details type tests such as dielectric, radio interference voltage (RIV), resistance measurement, continuous current, short-time and peak withstand current, EMC tests, tightness tests, and auxiliary circuit tests. It introduces updated procedures for breaking tests with specific transient recovery voltages (TRVs) and specifies clear conditions for switch behavior during making and breaking tests.

• Technical Updates in 2021 Edition

  • Alignment with related IEC standards for consistency and harmonization
  • New annex for earth fault current calculation guidance
  • Refined rules for combining 50 Hz and 60 Hz switching tests
  • Clarifications on restrike allowances and short-circuit making tests
  • Defined vacuum integrity check after mechanical operations
  • Consolidated single-phase capacitive test voltages verified by simulation and calculation

Applications

IEC 62271-103:2021 applies extensively in the design, manufacture, and testing of high-voltage AC switches used in:

• Electrical power transmission and distribution networks
• Substation equipment and installations
• Industrial power systems requiring medium voltage switching
• Controlgear assemblies in utilities and infrastructure projects
• Switchgear integrating specialized breaking capabilities such as for cable and line charging, capacitor banks, and earth fault detection

By ensuring compliance with this standard, stakeholders can guarantee reliable switching performance, safety, and longevity of high-voltage switchgear devices. This supports grid stability, fault management, and operational efficiency in electrical networks.

Related Standards

• IEC 62271-1:2017 – General rules for high-voltage switchgear and controlgear
• IEC 62271-102:2018 – Circuit-breakers
• IEC 62271-100 – High-voltage circuit-breakers – Test procedures
• IEC 60071 – Insulation coordination
• IEC 61378 – Converter transformers
• IEC 60947 – Low-voltage switchgear and controlgear

These related standards provide a broader framework ensuring consistency in electrical switchgear quality, safety, and interoperability across different components and voltage classes.

Keywords: IEC 62271-103, high-voltage AC switches, switch-disconnectors, medium voltage switchgear, rated voltage 1 kV to 52 kV, electrical endurance, mechanical endurance, switchgear testing, transient recovery voltage, breaking current ratings, IEC standards, power distribution equipment, switchgear design and construction.