Power and Cooling — NBD-OM-001

5.1 Utility intake

Supply arrives from the transmission network at the substation yard (Section 1.4). Transformers step it down to the voltage distributed on site. The substation is the largest single piece of plant the facility owns, and the only one it shares with the region: the lines that feed it continue past it.

Figure 5.1. Main substation. Incoming lines at the top of the drawing; transformers below. — Figure 5.1 Main substation. Incoming lines at the top of the drawing; transformers below. · drawing ref. NBD-DWG-SUBSTATION

Figure 5.2. Indoor switchgear at the substation. Every panel is labelled; the labels are for the equipment's manufacturer. — Figure 5.2 Indoor switchgear at the substation. Every panel is labelled; the labels are for the equipment's manufacturer. · drawing ref. NBD-DWG-SUBSTATION2

warning

Transmission and distribution equipment is energised continuously. Arc flash boundaries are marked on the floor for a person who will not stand at them.

5.2 Switchgear and distribution

Switchgear divides the supply into independent paths so that any single path can fail without the halls noticing. Each rack in the facility is fed by two paths (Section 3.3). The facility switches between them as needed and records that it did.

Figure 5.3. Switchgear line-up. Two independent paths leave this room for every hall. — Figure 5.3 Switchgear line-up. Two independent paths leave this room for every hall. · drawing ref. NBD-DWG-SWITCHGEAR

5.3 Standby generation

If the utility supply is lost, standby generators start automatically and carry the facility's load until supply returns. The generators are tested on a schedule: started monthly, and run under load once a year. The test is a real event; the facility simply chooses when it happens.

Figure 5.4. Standby generator, enclosure cut away to show the engine. The generator hall holds one per bay. — Figure 5.4 Standby generator, enclosure cut away to show the engine. The generator hall holds one per bay. · drawing ref. NBD-DWG-GENSETS

Figure 5.5. Generator set on its steel skid. — Figure 5.5 Generator set on its steel skid. · drawing ref. NBD-DWG-GENSETS2

Test	Interval	Performed by	Witnessed by
No-load start	Monthly	The facility	—
Load bank test	Annually	The facility	—
Full transfer	Annually	The facility	—

5.4 Energy storage

Between the loss of supply and the start of the generators there is an interval of seconds. It is bridged by batteries, which hold enough energy to carry the facility for minutes, and little more. They are a short breath, held.

Figure 5.6. Battery rack. Cells in strings; each cell reports its own condition. — Figure 5.6 Battery rack. Cells in strings; each cell reports its own condition. · drawing ref. NBD-DWG-BATTERY

caution

Stored energy is present in every battery string whether or not the facility is running.

5.5 Cooling plant

All power delivered to the halls becomes heat. The cooling plant removes it: chillers and pumps carry it in water from the halls to the cooling towers (Section 1.5), where it leaves the site.

The cooling plant is the second-largest consumer of power on the site. It uses power to remove the heat made by power.

Figure 5.7. Chiller unit with its pumps and pipework. — Figure 5.7 Chiller unit with its pumps and pipework. · drawing ref. NBD-DWG-CHILLERS

Figure 5.8. Chilled water mains: supply, return, and the crossover between them. — Figure 5.8 Chilled water mains: supply, return, and the crossover between them. · drawing ref. NBD-DWG-PIPES

5.6 Immersion cooling

In the densest halls the equipment is not cooled by air. It is submerged in a dielectric fluid in open tanks, and the fluid carries the heat away. Components are lifted out of the fluid for replacement by handling units (Section 4.2) and lowered back in.

Figure 5.9. Immersion tank, casing cut away. The equipment stands in fluid, upright, like a rack laid on its back. — Figure 5.9 Immersion tank, casing cut away. The equipment stands in fluid, upright, like a rack laid on its back. · drawing ref. NBD-DWG-TANKS

5.7 Materials

The equipment in this facility is made of materials extracted elsewhere: copper for conductors, silicon for processors, lithium and cobalt for the batteries, rare earths for the magnets in its motors and drives, and water, before and during manufacture, in quantities not recorded here.

The facility does not see these places. They are listed so that the manual is complete. The facility's footprint is larger than its site; the site is only the part of the footprint that has a fence.

Material	Used in	Origin
Copper	Conductors, busways, cooling	Mined; recorded in supply documents
Silicon	Processors, memory, solar cells	Refined from quartz
Lithium	Batteries	Brine and ore
Rare earth elements	Motors, drives, magnets	Mined and separated
Water	Manufacture and cooling	Various

performed by	verified by	date	signature

Sign-off fields are provided for regulatory form. No entry is expected.