Data Center Power Distribution
Power Distribution spans the entire stack—from utility interconnects and onsite substations down to server PSUs and on-board VRMs. AI-era densities demand high-efficiency conversion, rigorous selectivity, and fast failover. This page maps the end-to-end path, design patterns, BOM elements, vendor landscape, and how digital twins improve reliability and efficiency.
Layer Impact
| Layer | Power Elements | Notes |
|---|---|---|
| Campus | HV feeders, substations (GIS/AIS), main transformers, protection relays | 200–1000+ MW; utility agreements, interconnect protection, sectionalization |
| Facility | MV switchgear, step-down transformers, UPS plants, STS, main distribution boards | Selective coordination, arc-flash boundaries, metering, tie-breakers |
| Pod / Cluster | LV switchboards, busways, distribution panels, branch protection | Segmentation by failure domain; dual-fed A/B paths |
| Rack | A/B PDUs (single/three-phase), busbar tap-offs, 48 VDC pilots | Telemetry, outlet switching, breaker/GFCI choices, leakage detection coordination |
| Server | Redundant hot-swap PSUs, 48 VDC/12 VDC rails, on-board VRMs | High-efficiency (>96%) PSUs, transient response for accelerators |
Architecture & Design Patterns
- Topologies: N, N+1, 2N, 2(N+1) across plant ? hall ? row ? rack; A/B power paths to contain faults.
- UPS Strategies: Double-conversion, line-interactive, rotary UPS; lithium-ion batteries replacing VRLA for higher density and lifecycle.
- Transfer: STS/ATS at facility or row; fast transfer for ride-through of transient utility events.
- Distribution Media: Busway vs cable tray; busway preferred for modularity and lower installation time.
- Voltage Strategy: MV at facility, LV at hall, with growing interest in 48 VDC distribution to racks for efficiency and cable sizing.
- Selectivity & Protection: Time-current coordination, zone-selective interlocking, arc-flash mitigation (AFR, arc quenching).
- Grounding/Bonding: Mesh-bonding for EMI control and safety; attention to liquid-cooling manifold continuity.
- Power Quality: Harmonics from non-linear GPU loads; active filtering and UPS input rectifiers to manage THD and PF.
- Monitoring: Branch-circuit metering, PUE dashboards, breaker status, oscillography at critical points.
- Digital Twins: One-line + EMT/ETAP/DIgSILENT models to simulate faults, transfers, harmonic flows, and energy optimization.
Bill of Materials (BOM)
| Domain | Examples | Role |
|---|---|---|
| Substations (Campus) | HV switchgear (GIS/AIS), power transformers, protection relays | Steps transmission to MV; provides primary protection and sectionalization |
| MV Distribution (Facility) | MV switchgear, bus ducts, MV/LV transformers, tie-breakers | Feeds halls; enables maintenance without downtime |
| UPS & Energy Storage | Double-conversion UPS, rotary UPS, Li-ion/VRLA batteries, flywheels | Ride-through, conditioning, and transient protection |
| Emergency Generation | Diesel/gas gensets, paralleling switchgear, ATS | Backup power for extended outages |
| Low-Voltage Distribution | LV switchboards, panelboards, RPPs, busway | Delivers A/B feeds toward rows and racks |
| Rack Power | A/B PDUs, breakers, metering, 48 VDC pilots | Last-mile distribution and telemetry |
| Server Power | High-efficiency PSUs, VRMs, OR-ing controllers | Point-of-load regulation for CPUs/GPUs/HBM |
| Controls & Monitoring | PMS/EMS, breaker status, waveform capture | Situational awareness and optimization |
Key Challenges
- Scale & Lead Times: Transformers and MV gear have 12–36 month lead times; plan spares and phased energization.
- Density at the Edge: 40–100 kW racks stress PDUs, plug/connector ratings, and cable heating.
- Harmonics & Inrush: Accelerator loads and PSU inrush can trip protection; soft-start and active rectification required.
- Selectivity: Poor coordination causes upstream trips; model and test time-current curves end-to-end.
- Arc-Flash Safety: High incident energy in MV/LV rooms; incorporate arc-resistant gear and remote racking.
- Efficiency vs Resilience: 2N doubles conversion losses; balance with high-efficiency modes and topology choices.
Vendors
Energy & Switchgear OEMs
| Vendor | Product / Solution | Domain | Key Features |
|---|---|---|---|
| Siemens | GIS/AIS switchgear, protection relays | HV/MV | Digital substations, arc-flash mitigation |
| ABB | MV/LV switchgear, prefab substations | HV/MV/LV | EconiQ low-GWP, modular bays |
| Hitachi Energy | Transformers, grid integration | HV/MV | High-efficiency transformers, FACTS integration |
| GE Vernova | Grid solutions, transformers | HV/MV | Protection and control suites |
| Eaton | MV/LV switchgear, PDUs, breakers | Facility/Rack | Zone-selective interlocking, arc reduction |
| Schneider Electric | Switchgear, PDUs, power monitoring | Facility/Rack | EcoStruxure PMS/EMS integration |
UPS, Battery, and Generation
| Vendor | Solution | Domain | Key Features |
|---|---|---|---|
| Vertiv | Liebert UPS (double-conversion), lithium-ion systems | Facility | High-efficiency ECO modes, scalable frames |
| Schneider Electric | Galaxy UPS, Li-ion/VRLA cabinets | Facility | Modular UPS blocks, PMS integration |
| Eaton | 93PM/93PR UPS, battery systems | Facility | Energy Saver System, advanced metering |
| Cummins / CAT | Diesel/gas generators, paralleling gear | Facility | Black-start capability, fast load acceptance |
| Tesla Energy / Fluence | Megapack / utility BESS | Campus | Peak shaving, renewable smoothing |
Prefabrication & Integration
| Vendor | Solution | Domain | Key Features |
|---|---|---|---|
| Modular Power Solutions (MPS) | Electrical skids (switchgear + UPS) | Facility | Factory-tested, rapid deployment |
| ABB Prefab Substations | Containerized HV/MV yards | Campus | Shorten interconnect schedule |
| Schneider Electric | EcoStruxure prefab power blocks | Facility | Standardized modules with PMS |
Future Outlook
- 48 VDC at Rack: Wider adoption to reduce copper, losses, and connector heat; server PSUs optimized for 48?PoL.
- Solid-State Transformers (SSTs): Faster, smarter conversion at campus edges for dynamic control and efficiency.
- Advanced Storage: Multi-hour BESS for grid support, UPS-battery hybrids, and coordinated EMS/PMS dispatch.
- DC Microgrids: Pilot LVDC distribution within halls for high-efficiency AI pods.
- Digital Twins Everywhere: Planning (ETAP/DIgSILENT), real-time state estimation, predictive maintenance, and automated transfer testing.
FAQ
- What’s the difference between N+1 and 2N? N+1 adds a single redundant module; 2N duplicates the entire path, enabling maintenance and fault tolerance without load risk.
- Why lithium-ion UPS batteries? Higher power density, better cycle life, lower HVAC burden vs VRLA.
- When use busway vs cables? Busway for modular growth and faster installs; cables for fixed, lower-density rows.
- Can racks be fed with 48 VDC? Yes; adoption is growing to support 40–100 kW racks with improved efficiency and cable sizing.
- How do digital twins help? They simulate faults, transfers, harmonics, and energy flows to optimize selectivity, efficiency, and maintenance windows.