Case study / 02Power distribution strategy
West Hall power strategy
The West Hall development at the Surrey campus has a design basis of about 12 MW of IT. Working directly for the client, we set the power distribution strategy: how power reaches the IT load, how it keeps running when equipment fails, and how it fits the space available.
IT design basis12 MWWest Hall development
UPS16 × 1 MVAModules sized to fit the space
Arrangement4 × 3 MWFour groups of four modules
ResilienceN+1Four make three in each group
What we did
- Set the power distribution strategy for the West Hall: incoming HV supplies, transformers, LV switchboards, UPS and bypass, standby generation and supplies to mechanical plant.
- Selected 1 MVA UPS modules to suit the space available, arranged in four groups of four, each four make three (N+1).
- Worked through load allocation, maximum demand and failure scenarios, including paired transformers and interlocked LV sections.
- Answered the design team’s technical queries, from UPS input, output and bypass currents and the behaviour of AI loads to neutral continuity during switching, restricted earth fault protection, selectivity, fault duty and voltage drop.
- Set out what the detailed design must still confirm, including a harmonic assessment, verified records and settings for retained equipment, and a verified sequence of operation.
Reading the capacity correctly
12 MW is the UPS output to the IT load. The power drawn upstream is greater, because the UPS also needs power for its own conversion losses and to recharge its batteries. Transformers, switchboards and the incoming supply have to be sized for that larger figure, not for the IT load alone.
Project experience of Mousa Consultancy’s director, acting directly for the client. Client name withheld. Figures are the design basis, not measured load.