K&K Data Service Inc.Data Center Engineering Lab

Data Center Lab

UPS, Battery and Generation

This series publishes working engineering analysis from K&K's data center program. Numbers are labeled [TARGET], [MODELED], [SENSITIVITY] or [FACT]; nothing here is field-measured data, and no article is a sealed engineering document. Each article states its own limits and open items.

Excerpt of a four-path power one-line showing paths A1, A2, B1 and B2 with per-path transformer, ATS and UPS tags
Four-path one-line excerpt: per-path transformer, ATS and UPS identities (study — not released for construction).
  1. KK-DCL-013A Nine-Unit 3-to-Make-2 UPS Does Not Cover 12.711 MW Protected LoadA nine-unit 3-to-make-2 arrangement cannot deliver 12.711 MW of protected load, and the arithmetic failure is independent of vendor choice.
  2. KK-DCL-014Strict 2N UPS Misses 0.711 MW Protected Load in Maintenance-Plus-FaultStrict 2N leaves 12 MW against 12.711 MW when one path is in maintenance and the healthy path loses a single UPS module.
  3. KK-DCL-0153-to-Make-2 UPS Retains 14 MW in the Maintenance-Plus-Fault CaseThe twelve-unit distributed-redundant arrangement retains 14 MW in the same stacked maintenance-plus-fault case that defeats strict 2N.
  4. KK-DCL-016Catcher UPS Fails Maintenance, Transfer Refusal, and Dual-Block FaultThe catcher topology fails catcher maintenance, transfer refusal and simultaneous dual-block fault by construction, which makes it a cost reference only.
  5. KK-DCL-0173.3 MWh Battery Is 5.2 Minutes on 2N, Not 10 Minutes on Both PathsBattery energy divided across a 2N pair yields one autonomy figure, not two, and the doubling error survives into the battery room area.
  6. KK-DCL-018A 10× Recharge Rate Overruns the Last 4% of the 15 MW Service CapAggressive recharge current consumes the residual margin between facility load and the service cap, turning recharge into a capacity event.
  7. KK-DCL-019Battery Recharge Margin Cannot Be Counted Twice Against the Service CapThe 642 kW margin already contains charging power, so subtracting 233 kW again fabricates a 409 kW spare that does not exist.
  8. KK-DCL-020Low-Voltage UPS Topology Does Not Reduce On-Site Generator CountGenerator count follows facility load and site N+1, so changing the low-voltage redundancy topology does not reduce the generator quantity.
  9. KK-DCL-021Restoration Must Isolate Before Assuming Utility-Generator ParallelThe restoration sequence must isolate before it assumes a parallel utility-generator transition, because the parallel permit is not yet evidenced.
  10. KK-DCL-022A 0.5-Point UPS Efficiency Change Moves About 65 kW of Facility LoadA half-point change in UPS efficiency moves about 65 kW of facility power, against a non-critical utility line of 85 kW in the same schedule; the two are the same order, not equal.