Setting up A Transformer in Proteus
The calculation Formula is L1/L2 = (V1/V2)^2
For Example: Design for 6 Volt input ,230volt 50Hz Not considered wattage just for simulation.
Assign L1 = 1H (but 1henry expectable for a 10 or 20 kW transformer)
Then L2 = 1/(230/6)^2
= 680.5293micro Henry