Analyse and possibly adjust unusual voltage levels

[lukasol]

i.e. if voltage = 400 kV --> set voltage 380 kV (similar to implementation of 60 kV as 110 kV structures.)

[lukasol]

If no implementation carried out, allow transformers of unusual voltage levels.

[lukasol]

Resolved with hard coded voltage adjustments:

• = 60kV and <165kV -> 110 kV

• <300kV -> 220 kV

• =300kV -> 380 kV