scottf,
The voltage derating only applies for anything exposed to air - power line insulators, t/f bushings, switchgear busbar support insulators, etc.
At altitude, air becomes a less effective insulator electrically (as I have just discovered), hence the voltage derating.
Also, at altitude...
electripete,
Yes, i am talking about voltage derating. The rated one-minute power frequency withstand voltage, the impulse withstand voltage and the maximum voltage rating must be corrected (derated) for altitudes above 1,000 metres for MV applications.
The continuous current rating must also...
All,
Can anyone explain the logic (physics) behind the need to derate at altitide.
To my twisted way of thinking, it is the opposite to what I would have thought.
At altitude, air is less dense, and I would have thought that this would have made it a better insulator - apparently it does not...
G'Day All,
What are the latest trends with the type of fire suppression systems being used in substations and switchrooms containing H.V, M.V. and L.V. switchgear and MCCs?
What is being used instead of Halon? Is there an alternative to CO2?
Thanks.
