Data Center Power Infrastructure Flashcards
7 cards from real CDCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Data Center Power Infrastructure flashcards as text
What is the function of a bypass isolation transformer in a UPS system?
Answer: To allow UPS servicing while maintaining power to the load via bypass path
A bypass isolation transformer provides galvanic isolation on the static bypass path, allowing the UPS to be fully isolated for maintenance while the load continues to receive utility power.
A data center has a PUE of 1.4 and IT load of 2 MW. What is the total facility power consumption?
Answer: 2.8 MW
Total facility power = IT load × PUE = 2 MW × 1.4 = 2.8 MW.
Which power topology provides the best isolation of IT equipment from utility power anomalies?
Answer: Online double-conversion UPS in VFI mode
Online double-conversion (VFI - Voltage and Frequency Independent) UPS continuously converts AC to DC and back to AC, completely isolating IT loads from all utility disturbances.
What is the purpose of a neutral grounding resistor (NGR) in a data center medium-voltage power system?
Answer: To reduce ground fault current magnitude and limit arc flash energy
A neutral grounding resistor limits ground fault current to a controlled level (typically 5–10 A), dramatically reducing arc flash energy and equipment damage during ground faults.
In a data center, what does 'N+1' mean when applied to automatic transfer switches (ATS)?
Answer: The minimum number of ATS units needed plus one additional for redundancy
N+1 redundancy means the minimum number of components required (N) plus one additional unit, so the system continues operating if any single ATS fails.
What is the typical efficiency advantage of a 480V power distribution system over a 208V system for the same IT load?
Answer: 480V reduces current by ~57%, lowering I²R distribution losses
Higher voltage (480V vs 208V) reduces current for the same power by a factor of ~2.3:1, and since losses are proportional to I², this significantly reduces distribution cable losses.
Which condition describes a 'hot aisle/cold aisle' arrangement's impact on power density capability?
Answer: Proper airflow separation enables higher power density by improving cooling effectiveness
Hot aisle/cold aisle containment separates supply and return air streams, improving cooling effectiveness and allowing higher power densities per rack by ensuring cold air reaches IT equipment inlets.