Patent ID: 7518266

Claim:
An electric power transmission system, comprising: (a) a group of individual utility customers interconnected by a local AC transmission network within a defined geographical area; (b) a DC transmission ring substantially surrounding the local AC transmission network, the DC transmission ring isolating the local AC transmission network from an AC generating station; (c) a first AC/DC converter electrically connected between the DC transmission ring and the AC generating station to receive and convert AC power from the AC generating station to DC power for distribution along the DC transmission ring; (d) a second AC/DC converter electrically connected between the DC transmission ring and the local AC transmission network, the second AC/DC converter adapted to receive and convert DC power from the DC transmission ring to AC power for distribution to the AC transmission network; and (e) a plurality of isolating DC-DC converters interposed at predetermined locations on the DC transmission ring for isolating faults on the DC transmission ring to prevent the faults from disturbing the system.