Transition from alternating current to direct current low voltage distribution networks

Maximising the capacity of the existing AC distribution network infrastructure by conversion to DC may hold significant advantages. In particular it may provide a greater flow of electrical energy within urban areas, allowing a lower investment cost for adoption of electrical vehicles and domestic heating. Integration with Smart Grid applications will require maintained levels of reliability, and improved efficiency and flexibility. The transition of the cable infrastructure from the legacy LVAC (low voltage alternating current) system to LVDC (low voltage direct current) is considered in this study. In particular this paper investigates the limitations of DC supplied through the existing distribution network without major re-construction, and proposes optimal configurations that could be adopted in a smart-DC distribution network. The implications for power flow in the network are considered with regards to existing cable limitations. It is concluded that a better understanding of cable and joint reliability is required before such changes are made to existing LV networks.