I had the privilege of a tour of a State-of-the-Art Data Center / Disaster Recovery Space designed building recently. I was in awe with the electrical systems within the facility.
The building consisted of 314000sq feet on three floors...here are some specs...
ELECTRICAL: Redundant service (13.8K volt)feeds six 2500kVA substations (capacity for 15)
EMERGENCY POWER: Eight 2MW Caterpillar diesel generators located on roof (capacity for 15) with three 30,000 gallon underground tanks to provide a minumum of 72 hours of continuous operation at full load.The original thought was to have the generators in the basement of the building near the service, but the mechanical contractor estimated that the wind velocity through the floor would have to be at speeds of up to 90 mph to remove the heat produced when running at full capacity, so they were put on the roof.I think he said there were three 1800kw load banks used for exercising the generators.
UPS SYSTEMS/PDUs: Multiple liebert UPS units installed and operating, each with C&D wet cell battery strings. 100 watts psf of redundant power to Raised Access Floors. The signal reference grounding grid work under the 3rd floor RAF has .9 ohms to earth. Dual-fed static switch PDUs installed and avalable for tenant use.
HVAC: 4500 tons of cooling capacity delivered from five 900 ton York chillers and 5 Marley cooling tower cells.
FIBER PROVIDERS: 13 fiber providers avaiable at prefered pricing.
EMERGENCY WATER: A 400,000 gallon water storage tank beneath the parking lot provides continuous chiller service at full capacity in the event of municipal interuption.
STRUCTURE: Steel frame with brick and glass pre-cut screenwalls.
An interesting method of cable support was used for tieing down the cables in the cable trays run throughout the floor area. They used string wraped around the cables to tie them to the tray instead of tiewraps.This method was used every 2 feet. Must have taken days.Each tie was done the same way.
It took 18 months and 100 million to construct the facility.
That sounds insane! Every time I see the specs for some of these datacenters, I am amzed at what goes in to them?
I am curious, how do they distribute the 13.8kV feeds to the substations in a redundant manner? I know almost nothing about MV distro, but it does intrest me! Do the cables run in conduit? What size wire is normally used? Anything else worthwhile?
Where was it? I did some work in a building like that where the building was empty all the time, hundreds of work stations and computers and server racks all just sitting there waiting for a disater somewhere. There business is like insurance I guess, you pay for their service and hope you never need it.
We've got a phone co. switching station in town we tour with the FD once a year or so.
It went from three floors of wire, relays, and loud humming to one floor (actually, about a medium office area of the floor about 20' x 30') with digital switching and fiber optic cabling. Still a few old realy boards, but not many.
The busswork in that building is incredible. All phone voltage (90 vdc IIRC), but the copper is about 1/4 x 3", and tied to old sotred acid batteries in glass in the basement.
mhulbert, Redundant medium voltage distribution is done in much the same way low voltage is distributed redundantly. You have to choose an overall philosophy, N+1 or 2N etc. Then they are fed via main tie-tie main switchgear to other redundant switchgear. Don't forget that the gens are redundant too (or at least should be), and service the switchgear in redundant schemes with many fail over scenarios available with automatic and manual backups.