General Information

Abstract

IEC 60071-1:2006 applies to three-phase a.c. systems having a highest voltage for equipment above 1 kV. It specifies the procedure for the selection of the rated withstand voltages for the phase-to-earth, phase-to-phase and longitudinal insulation of the equipment and the installations of these systems. It also gives the lists of the standard withstand voltages from which the rated withstand voltages should be selected. This standard recommends that the selected withstand voltages should be associated with the highest voltage for equipment. This association is for insulation co-ordination purposes only. The requirements for human safety are not covered by this standard. Although the principles of this standard also apply to transmission line insulation, the values of their withstand voltages may be different from the standard rated withstand voltages. The apparatus committees are responsible for specifying the rated withstand voltages and the test procedures suitable for the relevant equipment taking into consideration the recommendations of this standard. NOTE: In IEC 60071-2, Application Guide, all rules for insulation co ordination given in this standard are justified in detail, in particular the association of the standard rated withstand voltages with the highest voltage for equipment. When more than one set of standard rated withstand voltages is associated with the same highest voltage for equipment, guidance is provided for the selection of the most suitable set. The main changes from the previous edition are as follows:  - in the definitions (3.26, 3.28 and 3.29) and in the environmental conditions (5.9) taken into account clarification of the atmospheric and altitude corrections involved in the insulation co-ordination process;  - in the list of standard rated short-duration power frequency withstand voltages reported in 5.6 addition of 115 kV;  - in the list of standard rated impulse withstand voltages reported in 5.7, addition of 200 kV and 380 kV; - in the standard insulation levels for range I (1kV < Um   245 kV) (Table 2) addition of the highest voltage for equipment Um = 100 kV; - in the standard insulation levels for range II (Um   245 kV) (Table 3) replacement of 525 kV by 550 kV and of 765 kV by 800 kV; - in order to remove that part in the next revision of IEC 60071-2, addition of Annex A dealing with clearances in air to assure a specified impulse withstand voltage in installation; - in Annex B, limitation at two Um values for the values of rated insulation levels for 1kV < Um 245 kV for highest voltages for equipment Um not standardized by IEC based on current practice in some countries.
It has the status of a horizontal standard in accordance with IEC Guide 108.

Status
Not Published
Current Stage
PPUB - Publication issued
Start Date
23-Jan-2006

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Overview

IEC 60071-1 - Insulation co‑ordination: Part 1: Definitions, principles and rules is the international standard that defines the principles and rules for selecting rated withstand voltages in three‑phase a.c. systems with equipment highest voltage above 1 kV. The standard specifies how to associate standard rated withstand voltages with the highest voltage for equipment (Um) for insulation co‑ordination purposes. It is a horizontal IEC standard (IEC Guide 108) and complements IEC 60071-2 (Application Guide), which provides detailed justification and selection guidance.

Key topics and requirements

  • Scope: Applies to three‑phase a.c. systems with Um > 1 kV; does not cover human safety requirements.
  • Voltage selection procedure: Procedure for selecting rated withstand voltages for:
    • Phase‑to‑earth insulation
    • Phase‑to‑phase insulation
    • Longitudinal insulation of equipment and installations
  • Standard rated withstand voltages: Lists of standard short‑duration power‑frequency and impulse withstand voltages from which the rated values should be selected; recent editions added specific values (e.g., 115 kV for short‑duration power frequency; 200 kV and 380 kV for impulse).
  • Association with Um: Recommends associating selected withstand voltages with the highest voltage for equipment for insulation co‑ordination only.
  • Environmental corrections: Clarifies atmospheric and altitude corrections to be applied in insulation co‑ordination.
  • Insulation level updates: Adjustments to standard insulation levels and Um entries (addition of Um = 100 kV in one range; replacement of some high Um values).
  • Annexes: Addition of Annex A (clearances in air to assure specified impulse withstand voltages) and Annex B (limitations for rated insulation levels for some non‑standard Um values).
  • Responsibility: Apparatus committees must specify rated withstand voltages and appropriate test procedures for specific equipment, taking IEC 60071-1 recommendations into account.
  • Transmission lines: Principles apply but transmission line withstand values may differ from listed standard rated voltages.

Applications and users

IEC 60071-1 is essential for:

  • Electrical engineers and designers of substations, switchgear, transformers and high‑voltage equipment
  • Manufacturers creating specifications and test requirements for insulation systems
  • Utilities and system planners performing insulation co‑ordination studies
  • Standards committees and test laboratories defining rated withstand voltages and test methods

Practical uses include selecting insulation levels, defining clearances, specifying test voltages, and harmonizing equipment ratings for reliable system performance.

Related standards

  • IEC 60071-2 (Application Guide) - provides detailed justification and selection guidance for rules in IEC 60071-1
  • Equipment‑specific IEC standards - apparatus committees set final rated withstand voltages and test procedures consistent with IEC 60071-1 recommendations

Keywords: IEC 60071-1, insulation co‑ordination, rated withstand voltages, phase‑to‑earth, phase‑to‑phase, impulse withstand voltage, short‑duration power‑frequency, highest voltage for equipment, insulation levels.

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Frequently Asked Questions

IEC 60071-1 is a standard published by the International Electrotechnical Commission (IEC). Its full title is "Insulation co-ordination - Part 1: Definitions, principles and rules". This standard covers: IEC 60071-1:2006 applies to three-phase a.c. systems having a highest voltage for equipment above 1 kV. It specifies the procedure for the selection of the rated withstand voltages for the phase-to-earth, phase-to-phase and longitudinal insulation of the equipment and the installations of these systems. It also gives the lists of the standard withstand voltages from which the rated withstand voltages should be selected. This standard recommends that the selected withstand voltages should be associated with the highest voltage for equipment. This association is for insulation co-ordination purposes only. The requirements for human safety are not covered by this standard. Although the principles of this standard also apply to transmission line insulation, the values of their withstand voltages may be different from the standard rated withstand voltages. The apparatus committees are responsible for specifying the rated withstand voltages and the test procedures suitable for the relevant equipment taking into consideration the recommendations of this standard. NOTE: In IEC 60071-2, Application Guide, all rules for insulation co ordination given in this standard are justified in detail, in particular the association of the standard rated withstand voltages with the highest voltage for equipment. When more than one set of standard rated withstand voltages is associated with the same highest voltage for equipment, guidance is provided for the selection of the most suitable set. The main changes from the previous edition are as follows: - in the definitions (3.26, 3.28 and 3.29) and in the environmental conditions (5.9) taken into account clarification of the atmospheric and altitude corrections involved in the insulation co-ordination process; - in the list of standard rated short-duration power frequency withstand voltages reported in 5.6 addition of 115 kV; - in the list of standard rated impulse withstand voltages reported in 5.7, addition of 200 kV and 380 kV; - in the standard insulation levels for range I (1kV < Um 245 kV) (Table 2) addition of the highest voltage for equipment Um = 100 kV; - in the standard insulation levels for range II (Um 245 kV) (Table 3) replacement of 525 kV by 550 kV and of 765 kV by 800 kV; - in order to remove that part in the next revision of IEC 60071-2, addition of Annex A dealing with clearances in air to assure a specified impulse withstand voltage in installation; - in Annex B, limitation at two Um values for the values of rated insulation levels for 1kV < Um 245 kV for highest voltages for equipment Um not standardized by IEC based on current practice in some countries.<br /> It has the status of a horizontal standard in accordance with IEC Guide 108.

IEC 60071-1:2006 applies to three-phase a.c. systems having a highest voltage for equipment above 1 kV. It specifies the procedure for the selection of the rated withstand voltages for the phase-to-earth, phase-to-phase and longitudinal insulation of the equipment and the installations of these systems. It also gives the lists of the standard withstand voltages from which the rated withstand voltages should be selected. This standard recommends that the selected withstand voltages should be associated with the highest voltage for equipment. This association is for insulation co-ordination purposes only. The requirements for human safety are not covered by this standard. Although the principles of this standard also apply to transmission line insulation, the values of their withstand voltages may be different from the standard rated withstand voltages. The apparatus committees are responsible for specifying the rated withstand voltages and the test procedures suitable for the relevant equipment taking into consideration the recommendations of this standard. NOTE: In IEC 60071-2, Application Guide, all rules for insulation co ordination given in this standard are justified in detail, in particular the association of the standard rated withstand voltages with the highest voltage for equipment. When more than one set of standard rated withstand voltages is associated with the same highest voltage for equipment, guidance is provided for the selection of the most suitable set. The main changes from the previous edition are as follows: - in the definitions (3.26, 3.28 and 3.29) and in the environmental conditions (5.9) taken into account clarification of the atmospheric and altitude corrections involved in the insulation co-ordination process; - in the list of standard rated short-duration power frequency withstand voltages reported in 5.6 addition of 115 kV; - in the list of standard rated impulse withstand voltages reported in 5.7, addition of 200 kV and 380 kV; - in the standard insulation levels for range I (1kV < Um 245 kV) (Table 2) addition of the highest voltage for equipment Um = 100 kV; - in the standard insulation levels for range II (Um 245 kV) (Table 3) replacement of 525 kV by 550 kV and of 765 kV by 800 kV; - in order to remove that part in the next revision of IEC 60071-2, addition of Annex A dealing with clearances in air to assure a specified impulse withstand voltage in installation; - in Annex B, limitation at two Um values for the values of rated insulation levels for 1kV < Um 245 kV for highest voltages for equipment Um not standardized by IEC based on current practice in some countries.<br /> It has the status of a horizontal standard in accordance with IEC Guide 108.

IEC 60071-1 is classified under the following ICS (International Classification for Standards) categories: 29.080.30 - Insulation systems. The ICS classification helps identify the subject area and facilitates finding related standards.

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Standards Content (Sample)


SLOVENSKI STANDARD
01-junij-1996
Insulation co-ordination - Part 1: Definitions, principles and rules
Insulation co-ordination - Part 1: Definitions, principles and rules
Coordination de l'isolement - Partie 1: Définitions, principes et règles
Ta slovenski standard je istoveten z: IEC 60071-1
ICS:
29.080.01 (OHNWULþQDL]RODFLMDQD Electrical insulation in
VSORãQR general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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