Totally Integrated Power - Application Models for Power Distribution: Data Centres

Overview

The manual moves in sequence through planning tasks, availability concepts, MV switchgear, cast-resin transformers, standby generator sets, UPS, LV switchboards, sub-distribution and power management. Availability is defined as A = MTBF / (MTBF + MTTR) and the BSI availability classes are reproduced, which ties the redundancy decision to a measurable quantity instead of intuition. The space-planning section gives tier-dependent infrastructure space factors: Tier II versus Tier I ranges from x1.2 (n=5) to x2 (n=1), Tier III is 1.25 times Tier II, Tier IV (n+n) is 2 times Tier I, and Tier IV (n+1)+(n+1) is 2.4-4 times Tier I.

For the same IT load, the grey space therefore grows sharply as redundancy rises. In the worked example, a 2,400 kW ICT load at PUE 1.5 gives 3,600 kW total, four computer rooms of 300 m2 and roughly 2,400 m2 of total area. The (N+1)+(N+1) design installs 7,200 kVA of UPS apparent-power capacity for that load; the source notes that kVA and kW are different units, so the figure alone is not a real-power multiplier.

Swing concepts are shown to recover utilisation. It is a 2013 vendor manual: product and topology examples reflect Siemens' system approach and do not track every detail of the current Uptime Tier Standard. It still provides a calculation skeleton aligned with IEC 60364, IEC 61439, IEC 62040-3 and EN 50600, which makes it a good starting reference for early-stage sizing.

Key points

1. Availability A = MTBF / (MTBF + MTTR).
2. Space factors: Tier II vs I x1.2 (n=5) to x2 (n=1); Tier III vs II x1.25; Tier IV (n+n) vs I x2; Tier IV (n+1)+(n+1) vs I x2.4-4.
3. Example: 2,400 kW ICT x PUE 1.5 = 3,600 kW total; 4 computer rooms x 300 m2; about 2,400 m2 total.
4. The (N+1)+(N+1) example installs 7,200 kVA of UPS apparent power for 2,400 kW ICT; kVA and kW differ, so this is not a real-power multiplier.
5. Critical (ICT) to infrastructure power split is about 2:1 (PUE about 1.5).
6. Safety-services changeover is typically within 15 s (0.15 s for some circuits).
7. Cast-resin transformers go up to 2,500 kVA; forced ventilation can lift a 1,000 kVA unit to about 1,300-1,500 kVA.

Using it in design

• Use the tier factors as defaults in the early-stage area estimator: grey space = white space x factor.
• Show installed UPS / IT load per topology as a cost KPI (N=1.0, 2N=2.0, 2(N+1)=about 3.0).
• Build the availability calculator on A=MTBF/(MTBF+MTTR) with series and parallel composition.
• Keep kVA and kW separate: report redundancy multipliers on real power and UPS capacity on apparent power.

Who should read it

Design engineers who need to estimate redundancy and floor area for a data centre electrical chain early.

Related standards

• IEC 60364
• IEC 61439
• IEC 62040-3
• EN 50600
• Uptime Tier Standard: Topology
• BSI High-Availability Compendium

Publication details

Authors

Siegbert Hopf

Publisher

Siemens

Year

2013

Document language

English

Source type

Manufacturer

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation