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Glossary List

2N Redundancy

Alternating Current (AC)

Ambient Temperature

Arc Flash

Autotransformer

Bayonet Fuse

BIL (Basic Insulation Level)

Bushing

Circuit Breaker

Cooling Class (ONAN / ONAF / KNAN)

Current

Current Transformer (CT)

Dead-Front Construction

Delta Connection

Delta-Wye Transformer

Dielectric Strength

Dielectric Withstand (Hipot) Test

Direct Current (DC)

Dissolved Gas Analysis (DGA)

Distribution System

Distribution Transformer

DOE Efficiency Standards (10 CFR 431)

Dry-Type Transformer

E-House (Electrical House)

Eddy Currents

Efficiency

Energization

Excitation Current Test

Factory Acceptance Testing (FAT)

Fault Current

Frequency (Hertz)

Grid Interconnection

Grounding (Ground)

Harmonics

IEEE C57 Standards Family

Inrush Current

Instrument Transformer

Insulation

Insulation Class (Thermal Class)

Insulation Resistance (Megger) Test

Interrupting Rating

IP Rating (Ingress Protection)

Isolation Transformer

K-Factor

Kilowatt (kW)

Kilowatt-Hour (kWh)

kVA (Kilovolt-Ampere)

Lead Time

Lightning Impulse Test

Liquid Cooling (Data Center)

Liquid-Immersed Transformer

Live-Front Construction

Load Loss (Winding Loss)

Load-Break Switch

Loop Feed

Medium-Voltage (MV) Switchgear

Mineral Oil (Transformer Oil)

Modular (Prefabricated) Substation

Modular Data Center (MDC)

Moisture Content Analysis

N+1 Redundancy

Nameplate

Natural Ester Fluid

NEC (NFPA 70)

NEMA Enclosure Rating

Neutral

No-Load Loss (Core Loss)

Nominal Voltage

Online Transformer Monitoring

Overload

Pad-Mounted Transformer

Panelboard

Paralleling Transformers

Percent Impedance (%Z)

Point of Common Coupling (PCC)

Pole-Mounted Transformer

Power Factor

Power Factor / Tan Delta Test

Power Transformer

Power Usage Effectiveness (PUE)

Predictive Maintenance

Pressure Relief Device

Primary Winding

Protective Relay

Rack Power Density

Radial Feed

Radiator

Rated Capacity (kVA Rating)

Recloser (Auto Recloser)

Sealed Tank System

Secondary Winding

Short Circuit

Single-Phase Pad-Mounted Transformer

Single-Phase Power

Sound Level (Audible Noise)

Station-Class (Large Power) Transformer

Step-Up / Step-Down Transformer

Substation

Substation Transformer

Surge Arrester

Sweep Frequency Response Analysis (SFRA)

Switchgear

Tap Changer

Taps (Voltage Taps)

Temperature Rise

Three-Phase Power

Tier III Data Center

Transformer

Transformer Turns Ratio (TTR) Test

Transient

Turns Ratio

UL (Underwriters Laboratories)

Uninterruptible Power Supply (UPS)

Vector Group (e.g., Dyn11)

Voltage

Voltage Regulation

Winding

Wye (Star) Connection

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