The amount of power or "Wattage" that you can get at 230 VAC depends almost completely on what the supply authorities allow you to get at a given point in the distribution system.
50,000 Watt single phase 230 VAC transformers are available in NZ.
Larger would be possible.
Your question may refer to power from a wall socket or from a phase coming into a domestic premises or to an industrial circuit or a pole transformer, but you did not make it clear which of these you intended.
A domestic or household power plug is often rated at 10 A = 230 x 10 = 2300 Watt nominal.
The circuit that it is fed from may have several 10A outlets on it and may be fused at say 25 a = 230 x 25 = 5750 Watt - say ~= 6 kW.
A domestic hot water hater fast recovery element may be rated at 6 kW or maybe even 10 kW.
A single phase 230 VAC supply to a house will have a "pile fuse" which limits the current able to be fed to the house. This may be in the 60 A - 150 A range = ~ 13 to 34 kW.
This company Transformer specialties in my country will provide transformers up to 50 kVA = 50000/230 = 217 A single phase 230 VAC.