Standards Development

Scope

This TS is to determine atmospheric and altitude correction factors (temperature, pressure, humidity) for AC, SI, LI and DC test voltages in systems greater 1000 V AC or 1500 V DC relevant for installation up to 4000 m above sea level, for air gaps and clean insulators.

The existing atmospheric and altitude correction factor will be considered in order to check if they can be applied up to high altitude and to propose a common evaluation procedure for all relevant IEC standards.

Purpose

In the existing IEC standards several different procedures exist to evaluate the atmospheric and altitude correction factors for high voltage tests of air gaps and clean insulators. Therefore a harmonisation of the procedures is necessary. Also in addition a check should be made if the correction factors are still valid for tests at high altitude.

The altitude correction factor is a basis for the design of the equipment and the insulation coordination, but the applicability is at the moment limited up to 2000 m above sea level and the extension to higher altitudes should be evaluated based on the results of measurements.

Finally also the insulation coordination of low voltage equipment should be evaluated regarding the requirement and performance of e.g. printed board at 4000 m above sea level.