carona discharge at high altitudes

[vams]

I would like to get help regarding IEC Standards.

What do IEC Standards (6034 series) say about insulation for motors at high altitudes, say 3200m. Please explain the concept of carona discharge with regards to humidity, temperature and altitude. Also explain voltage derating at such high altitude.

 

[RRaghunath]

Generally IEC specifications apply for equipment installed below 1000 metres in altitude. Beyond 1000metre, derating will be applicable and for details the subject IEC can be referred.
Yes, higher insulation is also important at those altitudes due to the condition of rarified atmosphere. If not, it can cause higher corona discharges and failure.