No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Development and standardization of higher-voltage direct current power feeding system
Abstract
We discuss the advantage of highly efficient and reliable higher-voltage direct current (HVDC) power feeding systems and the standardization activities for the power interface conditions in ICT equipment. With the recent spread of Internet services, the power consumption of ICT services is increasing annually. Many data center servicers want to decrease the power consumption of ICT equipment, cooling systems, and power feeding systems. HVDC power feeding systems have recently drawn attention due to their high efficiency and reliability. Such systems are more efficient than AC power feeding systems and are as reliable as conventional -48-V DC power feeding systems. However, the feeding voltage of HVDC systems is DC 380-V, which is higher and different than the conventional voltage of DC -48 V. ICT equipment is needed to change the power supply unit's interface. Therefore, we are actively standardizing the power interface condition of power supply units in ICT equipment. The European standards bodies of the European Telecommunications Standards Institute and International Telecommunication Union consented to the power interface conditions this year.
There are lots of issues existed with the Power Supply System in DC Building, and it is controversial as these issues have not been solved completely. In recent years, worldwide attention has been focused on proposing the standards of 'HVDC power supply system' or 'up to 400Vdc power feed system' following with the development of the power supply system in data center. Many attentions from the worldwide research organizations or institutions have pointed out that these standards can be applied with DC Building. In this paper, the standards of the main organizations and institutions on HVDC power supply system are introduced. Then some definitions of the issues among the standards of these organizations or institutions are analyzed and compared. The requirements for designing the power supply system in DC Building are discussed based on the above issues, including the system topology and the key power electronic converters interfaced to the system. The analysis can be referenced for designing the equipment of the Power Supply System in DC Building and helpful for popularizing the DC Power Supply Technology.
This article describes the development of a higher-voltage (approximately 400 V) direct current power feeding system for information and communications technology (ICT) equipment. It has higher efficiency than conventional alternating current systems, which can reduce the system cost. High-efficiency power feeding systems are an effective way to reduce ICT power consumption as well as low-powerconsumption ICT equipment such as routers and servers and high-efficiency cooling systems.
In the past Intelec, many presentations and DC panel have shown the advantage of using 48V DC power supply for Telecom. Reliability, simple scalability, modularity, low cost maintenance, reduced footprint, higher power efficiency than AC back-up architecture, high safety.
In recent years, Higher Voltage Direct Current (HVDC) distribution systems have been proposed to reduce power consumption in telecommunication buildings and data centers. NTT FACILITIES and NTT Data conducted verification tests of a HVDC distribution system at a Tokyo data center from January 29 to October 30, 2009. This paper summarizes the results of studies on HVDC distribution systems obtained so far, describes verification tests based on those results, and examines the test results. The verification tests were conducted with the cooperation of domestic and international ICT equipment vendors. We measured the energy savings and stability of the power supply involved long-term powering of ICT equipments (servers and storages) with an HVDC system. The test results show the superiority of the HVDC distribution system over the existing AC system. These test results also validate the HVDC system specifications proposed by the NTT group for standardization. These results may develop the current vigorous discussion of international standardization for HVDC distribution systems.
In recent years, higher voltage direct current (HVDC) distribution systems have been developed to reduce power consumption in telecommunication buildings and data centers. Thus, a demonstration test has been conducted to determine the energy efficiency, power stability, and safety of the HVDC system. The demonstration test was conducted in an in-service data center. The test results show that the HVDC system is 5.8% more efficient than the existing AC system. It was also found that servers that were altered for HVDC use could reduce the power consumption by up to 7%. According to the results of simulations including the effect of air conditioning, HVDC system could reduce the total power consumption by 15%. These test results also show that the HVDC system has no problem in operation in terms of power stability and safety.
400VDC is becoming a new voltage interface for telecommunication buildings and data centers as well as for ICT equipment. 400VDC interface covers applications for up to 400VDC with a typical nominal voltage of 380VDC. Key drivers for utilizing a higher DC voltage are overall efficiency and reliability gains vs present solutions. However, introduction of a new 400VDC interface brings up some questions about personnel safety and implementation of system grounding. Although DC is considered safer than AC, till now datacom operators have been hesitant to deploy 400VDC because it's not as commonly used and well understood as AC. This paper addresses 400VDC grounding issues and recommends high resistance midpoint grounding concept, as an effective way to provide safe operation of 400VDC distribution systems. Today Europe, North America (NA), and Japan telecom/ datacom installations employ slightly different grounding concepts, practices, codes, or regulations. This paper also reviews different grounding models and their implementation praxis in Europe, NA, and Japan. Benefits and the disadvantages of different grounding concepts are discussed and explanation of the reasons for selection of high resistance midpoint grounding as a preferable model for 400VDC distribution system is provided.
The issues discussed in this paper revolve around the challenges faced and some of the progress to-date in development and deployment of 400Vdc power distribution networks targeted at telecom and data networks as an alternative to AC distribution and AC UPS power deployment.
We outline the specifications and performance of a 400 Vdc power distribution system with a 400 Vdc output rectifier. In 2008, The NTT-group have began developing a 400 Vdc distribution system for reducing power consumption and the usage of materials, such as copper in power cables. In conjunction with this project, NTT facilities has developed prototype rectifiers, a prototype voltage compensator used during interruption periods, and a prototype battery charger. These exhibit higher efficiency than conventional ones and also exhibit high output regulation to adapt charge condition required by valve-regulated lead acid batteries for backup.
High efficiency power feeding systems are effective solutions for reducing the ICT power consumption with reducing power consumption of the ICT equipment and cooling systems. A higher voltage direct current (HVDC) power feeding system prototype was produced. This system is composed of a rectifier equipment, power distribution unit, batteries, and the ICT equipment. The configuration is similar to a -48V DC power supply system. The output of the rectifier equipment is 100kW, and the output voltage is 401.4V. This paper present the configuration of the HVDC power feeding system and discuss its basic characteristics in the prototype system.
FY2008 Green IT Promotion Council Technical Study Committee Report
- Green
Green IT Promotion Council, " FY2008 Green IT Promotion Council Technical Study Committee Report, " 2009 (Japanese).
Pre roll-out field test of 400 Vdc power supply
- D Marquet
- O Foucault
- J Acheen
- J F Turc
- M Szpek
- J Brunarie
D. Marquet, O. Foucault, J. Acheen, J. F. Turc, M. Szpek and J. Brunarie, " Pre roll-out field test of 400 Vdc power supply, " Proc. of INTELEC 2011, Oct. 2011.
Survey on datacenter electricity consumption and green IT FY2010
- Institute Mic
- Ltd
MIC Research Institute Ltd., " Survey on datacenter electricity consumption and green IT FY2010, " MIC, 2010.