The only difference between a 50 Hz and 60 Hz electrical system is the impedance in the wires. The default impedance values in Design Master Electrical are based upon the 60 Hz tables in the NEC. If you are designing a 50 Hz system, you need to manually adjust the impedance values.
Make the change using the DM Electrical->Customization->Wire Sizing->Edit Project List command. You want to change the “X” value in the bottom grid in the dialog.
The conversion from 60 Hz to 50 Hz is linear. Multiply the impedance at 60 Hz by 5/6 to get the impedance at 50 Hz. You want to make this change to the X value only. The R value stays the same.