Back-up Power

As we want to be a Tier-4 data centre we need two thing:

An Uninterruptible Power Supply (UPS) able to supply our centre until the back-up generators turn on.
Back-up generators: they will turn on after the UPS and until the power from the grid is back.

We have a total power consumption of approximately 6MW. With units of 1.5MW we need 4 of them. But the Tier-4 imposes redundancy of these units of N+1, therefore at the final step or our design we will have:

5 units of Uninterruptible Power Supply

5 units of back-up diesel generators

Symmetra MW 1.6MW frame, 480V from Schneider Electric. It has the big advantage to be configurable for N+1 redundancy with its modules in parallel. The battery failure notification system is very useful for the maintenance team to prevent any failure, and theses UPS units are accessible from the data centre network so it’s easier for the maintenance to check the UPS “vital signs” and know if something seems wrong.

We chose diesel generators because even if it’s not a green option they are widely used in data centre for their fast reaction capacity and because they don’t need so much fuel in stock.

The model we chose is the GENERAC SD1500 with a power supply of 1.5MW. They are provided with enough tanks to last for 24 hours. If we want to be sure that it can handle the Scottish weather we can take the weather resistant option.