Hi guys,

What procedure is followed when the installation on MV compartments is made above 1000m altitude? Are chosen Compartments with higher insulation voltage?

If we have 10kV network, is needed to chose 20kV for exp.
How about Isc, which for 20kV is up to 16kA?

What is can we select?

regards

That won't be in England then.

The voltage withstand of air insulated equipment such as overhead lines, dry type transformers, and insulating bushings of oil filled transformers, declines at high altitude.
You may need to specify higher voltage insulators, contact the equipment suppliers for details.

The current carrying capacity of cables and transformers is also somwhat recuded because the thinner air is less effective at removing heat, you may find that current rating have to be reduced.
On the other hand, most high altitude places are also cold, and the lower ambient MAY compensate for the thinner air.

The short circuit withstand rating of equipment should be unaltered by altitude. The main factors are specific heat capacity, and mechanical strength.

The short circuit current may be calculated or estimated in the usual way, and for a given set of equipment wont be influenced by altitude.

Be aware though that if the original design called for say a 12 MVA transformer, and that if this is upsized to say 15MVA due to cooling concerns, then the larger transformer will probably result in a larger fault current.

Thank you broadgage.