US Patent 7851950 Power distribution system for data center

A power distribution system for computer systems in a computer room of a data center includes a first transformer and a second transformer. The first transformer transforms three-phase source power to three-phase intermediate power in a set of intermediate power lines. The intermediate power is transmitted in the set of intermediate power lines to a second transformer in or under the computer room. The second transformer transforms the three-phase intermediate power to operating power in a set of operating power lines at an operating phase-to-neutral voltage between about 220 volts and about 260 volts. The output of the second transformer is coupled to power distribution units in server racks in the computer room.