How a power substation fire shut down Heathrow Airport
What's a substation and are data centres vulnerable?
Heathrow Airport went dark yesterday after a critical power substation caught fire. What's a substation and are data centres vulnerable?
Airport closure
It's hard to miss the news from Heathrow, where the airport was forced to close because of a massive power outage.
- 1,300 flights disrupted.
- 200,000 passengers affected.
- No evidence of foul play.
Limited flights have resumed, but the sheer passenger volume at Europe's busiest airport means recovery will be challenging and protracted.
What are power substations for?
Power substations aren't often talked about. What are they?
Substations serve a few key purposes:
- Power distribution.
- Voltage transformation.
- Regulate power for grid stability.
They form the backbone of power grids, stepping down high-voltage electricity from transmission lines to lower voltages suitable for homes and businesses.
Single point of failure
Can problems at a single power substation bring down an entire data centre or other critical infrastructure? In theory, it shouldn't.
As a power substation represents a single point of failure, data centre operators typically try to hook their data centres to two separate substations.
To my knowledge, this is true for most, if not all, data centres in Singapore. Tanjong Kling (formerly "S'pore Data Centre Park") has 2 dedicated substations built just for it.
The outage at Heathrow suggests that either a second power substation wasn't available, or that it couldn't take up the load.
Backup power
Redundant substations aren't always the solution. Specifically, they are of no use if the power grid isn't reliable.
As such, data centres are designed to keep running even if the power grid fails completely. They have:
- UPS systems.
- Diesel generators.
- On-site fuel storage.
- Reliable diesel fuel supply.
News reports suggest that Heathrow does have backup generators, but they weren't adequate. To me, it sounded as if design compromises were made along the way.
Substations in data centres
As the demands of data centres surge, I've noticed a new trend. Increasingly, power substations are being built within the compounds of data centres in Southeast Asia.
A couple came to mind:
And oh, depending on capacity and space constrains, power substations can be as large as a soccer field!
If you are impacted by the Heathrow situation, I hope you are able to get back home soon!