Quiz: AI Data Center Electrical Infrastructure (Part 4)

10 questions from Part 4 of the guide. Score instantly; every explanation links to the chapter that derives the answer.

Roughly how many voltage-conversion stages does a conventional AC chain carry from utility interconnection (~230 kV) to the GPU die (~0.7 V)?
ThreeFiveNineFifteen
A modern AI server PSU (active front end) draws current at what distortion level — and what does that imply?
~30% THD — K-rated transformers are mandatory<5% THD — the harmonic problem largely disappears, replaced by synchronized load transients~15% THD — same as legacy serversTHD is no longer measurable at these power levels
Why does the 13th harmonic matter so much more than the 5th for transformer heating?
it carries more currenteddy losses scale with h² — the 13th heats ~169× the fundamental vs ~25× for the 5thit resonates with the grid frequencyit trips protective relays first
Moving row distribution from 208 V to 415 V three-phase does what to rack power per ampere?
Halves itNo change — voltage doesn't matterRoughly doubles itQuadruples it
At 800 VDC vs 415 VAC, how much more power fits through the same copper?
~25% more~60% more~157% more~400% more
Around what rack power does the conventional AC chain hit the wall that forces the DC fork?
~50 kW~100 kW~200 kW~1 MW
The solid-state transformer (SST) matters because it…
eliminates the need for a substationconverts 13.2 kVAC → 800 VDC in one ~98%-efficient step, collapsing the conversion chain (~87% utility-to-VRM)is cheaper than a conventional transformer todayremoves the transformer lead-time problem
What ampacity are AI halls now specifying for overhead busway, versus the legacy standard?
200 A, down from 400 A400 A — unchanged800–1,600 A, up from a legacy 400 A5,000 A trunk lines
The UPS role is being redefined in AI halls from 'ride through until the generator starts' to…
pure surge suppressionabsorbing the cluster's own MW-scale load transients at optimizer cadencelong-duration storage for demand response onlyit is being removed entirely
Why is the OCP in-rack bus fixed at 48 V?
it matches telecom heritage onlySELV touch-safety — staying under the <60 V threshold keeps the rack serviceable without HV procedureshigher voltages don't exist in DC parts48 V minimizes copper mass

Check your understanding: Electrical & Energy Infrastructure