Originally Posted by
Dubaian
Mr Fogg - a 100KVA DG would just about fit on the back of a pickup. Hardly a truck - unless you're using red-neck terminology.
The total standby load of a place like LGW will not be as great as you might think. Many non-essential systems can be shutdown. BMS can automatically load shed. Yes you might still need a few MW but a 3MW diesel set will just about fit in a 40' container. Parallel up a few in an auto-start, auto-sync config and you'd be there.
My guess is that LGW does already have backup power systems but that they were also affected by what took out the mains - i.e. flooding of substations. Water & Electricity do not mix well. Ideally you'd keep main and stand-by in separate locations (not just to avoid flooding - bomb attacks are another possibility) but it's not always feasible to totally segregate the systems.
I was Duty Manager at the rail station one afternoon some 20+ years ago when the mother and father of all electrical storms had lightning twice hitting and taking out the elektrickery sub station at Balcombe. The result was no elektrickery in a swathe from south of Croydon to Haywards Heath. The airport was closed down for over an hour as was the railway which had lost all traction power and signalling power. Some back-up generators were deployed in the airport but there were no take-offs. I believe that aircraft were still landing though.