Overtime anyone?

[Sureitsoff?]

Looks like the London dno staff will be working over the weekend.....

Heathrow Airport closed for at least 24 hours as passengers warned not to travel

Passengers have been warned not to arrive for scheduled flights as the airport continues to experience "a significant power outage"

www.express.co.uk

 

[davelx]

I'm surprised that LHR is not fed from two geographically separated substations with diverse cable routing around the airport, and with the ability to support the entire load from 9ne or other if one fails, as is often done for large data centres.

 

[JohnW2]

I'm surprised that LHR is not fed from two geographically separated substations with diverse cable routing around the airport, and with the ability to support the entire load from 9ne or other if one fails, as is often done for large data centres.

That's what a lot of people (including IATA) appear to be saying/.asking. It does seem very short-sighted, particularly if it is true that an incident affecting their primary power source can also take out some of the back-up systems!

 

[davelx]

Seems like a case of P^7 to me!

 

[ericmark]

My back-up, will keep what I consider essential, heating and freezers. But to run the whole house would mean it would not last long. It said on BBC the back-up systems kicked in as expected, so either the back-up not big enough, or it will not last long enough.

They talk about having to re-boot systems, I would have thought, would not need to do that with a back-up. Seems someone got it wrong somewhere. I do not remember any generators on T5, but had my accident before the job was finished.

 

[johnny2007]

I'm surprised that LHR is not fed from two geographically separated substations with diverse cable routing around the airport, and with the ability to support the entire load from 9ne or other if one fails, as is often done for large data centres.

Pi$$ up...brewery...

 

[davelx]

Generators in large installations are really only useful/intended to allow for a clean shutdown, or to bridge the gap whilst the affected systems are switched over to the alternative grid feed, Oh. wait a minute, there isn't one !

 

[JohnW2]

They talk about having to re-boot systems, I would have thought, would not need to do that with a back-up. Seems someone got it wrong somewhere. I do not remember any generators on T5, but had my accident before the job was finished.

If it's anything like the back-up generators I've seen activated in hospitals, they do not provide an uninterrupted supply - they usually start up and kick-in 30 seconds or more after a loss of primary power - so anything which is not supplied by a UPS probably would have to be re-booted.

 

[JohnW2]

Generators in large installations are really only useful/intended to allow for a clean shutdown ...

As I've just written, that (which implies UPS-like functionality) does not seem to have been the case with hospital back-up systems I've seen to operate

 

[davelx]

As I've just written, that (which implies UPS-like functionality) does not seem to have been the case with hospital back-up systems I've seen to operate

That's what we had (probably still do) at Reuters. Huge banks of lead-acid batteries in each machine room with inverters to bridge the gap whilst the gennies came online.

 

[JohnW2]

That's what we had (probably still do) at Reuters. Huge banks of lead-acid batteries in each machine room with inverters to bridge the gap whilst the gennies came online.

That is obviously the ideal - but, as I've said, not what I've seen happening in UK hospitals.

I've seen hospitals which do have separate supplies, 'maintained' in the manner you suggest, specifically for use by 'life-critical' equipment - but by no means man enough to go anywhere near taking over the entire supply, even for a very brief period.

However, perhaps the installations I've experienced (and, admittedly, much of that 'experience' is now very dusty!) are not 'typical'!

 

[plugwash]

Generators in large installations are really only useful/intended to allow for a clean shutdown, or to bridge the gap whilst the affected systems are switched over to the alternative grid feed, Oh. wait a minute, there isn't one !

I think you are confusing UPS's with generators.

UPS's are usually used to allow for a clean shutdown or switching over to an alternative feed or a generator. Generators are used when you want longer duration power. I remember one datacenter I used advertising they had something like 72 hours of fuel on site, plus a contract with a fuel-delivery firm to keep the tanks topped off.

Of course there is a business decision of what to gets UPS backup only (clean shutdown but no longer term backup), what gets Generator backup only (longer term backup but interruption for 30 seconds or so on power loss and possibly a brief interruption on power resumption) and what gets both.

I could be wrong, but I suspect a whole bunch of transportable generators may be about to get trucked into (or indeed may be being trucked into as we speak) heathrow to provide coverage while they rebuild the substation. My understanding is they hope to reopen the airport tomorrow and I doubt a major substation can be fully repaied in that time.

 

[davelx]

I think you are confusing UPS's with generators.

UPS's are usually used to allow for a clean shutdown or switching over to an alternative feed or a generator. Generators are used when you want longer duration power. I remember one datacenter I used advertising they had something like 72 hours of fuel on site, plus a contract with a fuel-delivery firm to keep the tanks topped off.

Of course there is a business decision of what to gets UPS backup only (clean shutdown but no longer term backup), what gets Generator backup only (longer term backup but interruption for 30 seconds or so on power loss and possibly a brief interruption on power resumption) and what gets both.

I could be wrong, but I suspect a whole bunch of transportable generators may be about to get trucked into (or indeed may be being trucked into as we speak) heathrow to provide coverage while they rebuild the substation. My understanding is they hope to reopen the airport tomorrow and I doubt a major substation can be fully repaied in that time.

I'm not confusing anything, I worked for Reuters at the DTC for 5 years before moving to their HQ in Fleet St. I know exactly what we had there. UPSs on each of the four machine floors, containerised generators on the roof and diversely routed mains supplies for separated substations. Each 19" rack cabinet had A-B power feeds. I'm a network design engineer and worked on their global finance information distribution network. Note: this was 25 years ago - we're talking big VAXclusters 10Mb/s Ethernet and 2Mbps Megastream leased lines were considered high speed.

PS it's now Telehouse South so Thomson Reuters have flogged it off. Take a look at the power spec on their website

Telehouse South

Data Centre Telehouse South is the latest addition to Telehouse’s iconic London Docklands Campus. Visit our site to find out about Telehouse South.

www.telehouse.net

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