📋 Case Study
Data Center Electrical Design: Tier IV Facility Transient Stability Review
Generator synchronization transients causing UPS bypass and 12ms brownouts during simulated utility loss
🏗️ Project Overview
12 MW hyperscale data center in Virginia with dual utility feeds and 2×2.5 MW diesel backup
🎯 Challenge
Generator synchronization transients causing UPS bypass and 12ms brownouts during simulated utility loss
🔧 Design Approach
Pre-synchronization load shedding + inertia emulation via flywheel UPS + CCT-based relay settings
📐 Design Diagram
AI-generated project design illustration
📐 Key Calculations
Critical Clearing Time (CCT)
π × (δ_max − δ_0) / (ω_s × P_accel)
Result: 142 ms
Set generator protection relays to 120 ms
Inertia Constant Contribution from Flywheel
H_flywheel = (0.5 × J × ω²) / S_base
Result: 2.1 s
Raised system H from 1.8s to 3.9s, improving damping
📊 Results
Zero brownouts in 327 failover tests; achieved Uptime Institute Tier IV certification💡 Lessons Learned
- •Flywheel inertia must be modeled as synchronous machine equivalent—not just energy storage
- •Relay coordination requires time-domain simulation, not just ETAP steady-state
✅ Key Takeaways
- 1Flywheel inertia must be modeled as synchronous machine equivalent—not just energy storage
- 2Relay coordination requires time-domain simulation, not just ETAP steady-state