Pre roll-out field test of 400 VDC power supply: The new alliance of Edison and Tesla towards energy efficiency

In the past Intelec, many presentations and DC panel have shown the advantage of using 48 V DC power supply for Telecom. Reliability, simple scalability, modularity, low cost maintenance, reduced footprint, higher power efficiency than AC back-up architecture, high safety. Higher voltage than 48V is required for higher power in telecom core centers and datacenters as well as for remote feeding e.g. of BTS transceivers at the top of mast. As ICT devices are everywhere, the DC distribution in the buildings is in focus in many fora or association such as the Emerge DC Alliance or CEPS pushing DC 400 V in the building and lower DC voltage distribution in the rooms (e.g. 24 or 48 V). Standardization bodies are very active to revise and finalize the relevant standards in ETSI, ITU-T, and ATIS, as will be seen in this paper. Nobody should be afraid by this come back to DC because technical and business risks are very limited provided a good design well known for more than one century of history. This paper briefly reminds this history and how DC is fully mastered in many safe and reliable use in public transportation, industry and industrialized in huge quantity of thousands of MW for solar energy A progressive migration towards a unified interface is quite possible with the use of DC input inverters and DC equipment operating at 380 VDC. A decisive roll-out towards the very simple DC architecture is initiated. Several field experiments have been launched at different scale from kiloWatt to MegaWatt, leaded by major operators, manufacturers and research centers (NTT, FT, Emerson, GE, Intel, IBM, Lawrence Berkeley National Laboratory, EPRI, etc,). This paper describes in details the field experience of DC 380 V systems in Orange datacenters and telecom site in France including the test of a 380 V Lithium-ion battery.