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IEC 61472-2-2021 pdf free

IEC 61472-2-2021 pdf free.Live working – Minimum approach distances – Part 2: Method of determination of the electrical component distance for AC systems from 1,0 kV to 72,5 kV.
This part of IEC 61472 specifies a method for determining the electrical component of the minimum approach distances for live working, for AC systems 1 kV up to and including 72,5 kV. This document addresses system overvoltages and the working air distances between equipment and/or workers at different potentials.
The withstand voltage and minimum approach distances determined by the method described in this document can be used only if the following working conditions prevail;
— workers are trained for, and skilled in, working live lines or close to live conductors or equipment:
— the operating conditions are adjusted so that the statistical overvoltage does not exceed the value selected for the determination of the required withstand voltage:
— transient overvoltages are the determining overvoltages;
— tool insulation has no continuous film of moisture present on the surface;
— no lightning is observed within 10 km of the work site;
— allowance is made for the effect of the conducting components of tools.
NOTE In some countries, special procedures have been developed to permit live working with surface moisture on tools at distribution voltages (below 50 kV).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org!
• ISO Online browsing platform: available at http://www.iso.org/obp
4 Minimum approach distance, DA
The minimum approach distance, DA. is determined by:
Du is the required minimum electrical distance, and
DE is the required ergonomic distance which is dependent on work procedures, level of
training, skill of the workers, type of construction, and such contingencies as inadvertent movement and errors in appraising distances (see Annex B for details).
5 Factors influencing the minimum approach distance
5.1 Control of system overvoltages
The maximum amplitude of overvoltages in the work area can be reduced by the usual practice of making the circuit-breaker reclosing devices inoperative, or by using protective gaps or surge arresters.IEC 61472-2 pdf free download.

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