Service Voltage 33 kV and 34,5 kV - Insulation voltage cables to be used

[Joao]

For this service voltages I believe that cable 18/30 (36) kV should not be used even designed for Umax=36 kV.

Also in most cases earthing regime is IT.

In this way may be the best technical solution is cable 26/45 kV and not use 18/30 (36) kV cable.

 

[electrofelon]

I am not entirely clearn on your syntax and ratings. It appears you are from Portugal. Here in the States we commonly have 35 KV cables. An IT grounded system would typically have a 133% insulation level.