1 Scope
2 References
3 Definitions
3.1 Terms defined elsewhere
3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Present situation of a telecommunication or data centre powering
solution and motivation for migration to up to 400 VDC
7 General evolution cases during migration
7.1 Present situation
7.2 DC/DC converter related considerations
7.3 400/AC migration inverter consideration
7.4 Long distance transport in −48 V/ up to 400 VDC/−48
V in centre and multistep migration
7.5 Combined migration cases
7.6 Grid/back-up generator 400 DC switch replacing AC mechanical
switch
8 Up to 400 VDC batteries
9 Migration of up to 400 VDC remote power to local up to 400 VDC power
system
10 Coupling renewable energy to existing buildings distribution with
migration to up to 400 VDC
11 Up to 400 VDC cabling, earthing and bonding in the migration period
12 Electrical safety requirements
13 Electromagnetic compatibility requirements at the input of
telecommunication and datacom (ICT) equipment
14 Impacts on energy efficiency and other key performance indicators
(environmental impact, life cycle assessment)
Annex A – Power supply and interface considerations
Appendix I – Review of some papers on up to 400 VDC migration solutions,
advantages and implementation decision and process
I.1 Transformer-less 2 kW non-isolated 400 VDC/230 VAC single
stage micro inverter
I.2 A service provider's decision to move from 48 V to 380 V
powering: The problem statement, technical assessment, financial analysis and
practical implementation plan
I.3 Energy-saving effects of supercomputers by using on-site solar
power and direct high‑voltage direct current (HVDC) feeding systems
I.4 Model-based fault current estimation for low
fault-energy 380 VDC distribution systems
Appendix II – Details on some saving assessment of migration to up to 400
VDC
II.1 Energy efficiency
II.2 Energy cost reduction
II.3 Saving on material, area in ICT room and labour
II.4 Less copper and installation cost, progressive installation by
modularity
Bibliography