There is no simple way to make a 277/400 volt system.
There are only 2 common ways to make a multi-voltage system, single phase 3 wire or 3 phase 4 wire.
With a single phase 3 wire supply, the higher voltage is twice the lower one, a common example being the 120/240 volt residential service in the USA.
With a 3 phase 4 wire supply, the higher voltage is 1.7 times the lower voltage, for example 120/208 or 277/480.
Europe normally uses 3 phase 4 wire at a nominal 230/400 volts.
(the actual voltage tends to be nearer 240/415 in the UK and nearer 220/380 in mainland Europe.)
Less common European supplies include
3 phase 4 wire at 127/220 volt
3 phase 3 wire at 220 volt
3 phase 4 wire at 400/690 volt
1 phase 3 wire at 230/460 volt.
One could of course devise a single phase supply at 277/400 volts by means of a suitable transformer, and this might be done within equipment, but as a utilisation voltage ? I doubt it.
Perhaps a typo ? or the rating of some equipment that will accept a range of voltages from 277 up to 400 ?