380-VDC power distribution system for 4-MW-scale cloud facility

In February 2014, the NTT Group officially announced that it has launched a high voltage direct current (HVDC) (380-VDC) with a 4-MW-scale power supply system for the Tokyo metropolitan area. Activities, such as international standardization, has led to the commercial commencement of a full-fledged 380-VDC power supply system, demonstration projects, and technology development, which took more than 10 years. For the completion of the 380-VDC power supply system, evaluation, analysis and development, and demonstration of power supply system parts and equipment were necessary. The 380-VDC power supply system is a novel concept completely different from that of AC or 48-VDC systems. There are some technology gaps to provide breakthrough solutions. Prior to development, technology must be codified for the introduction of a safe optimal power supply method, grounding scheme, protection against electric shock, such as overcurrent protection, and stability and noise immunity. Recently, there have been many excellent reports from around the world. This paper focuses on promoting the introduction of our 380-VDC supply system into business and the long-term (over 10 years) development of the 380-VDC power supply system by the NTT Group.