Pad-Mounted Transformer, Three-Phase Distribution Transformers

Service condition

Normal Condition

Ambient temperature

Indoor

-5°C to +40°C

Outdoor

-10°C to +40°C

Humidity

90%

Altitude

≤1000m

Pollution

Level I-Light

Level II-Medium

Earthquake

UBC Zone 3

Special Condition

Ambient temperature

Indoor

-15°C to +40°C, -25°C to +40°C

Outdoor

-10°C to +50°C, -25°C to +40°C

-40°C to +40°C

Humidity

95%, 98%

Altitude

≤2000m, ≤3000m, ≤4000m

Pollution

Level III-Heavy

Level IV-Very Heavy

Earthquake

UBC Zone 4

K-factor

3, 5, 7, 9, 11, 13, 15, 17

Standard code

IEEE Std C57.12.00™-2010 standard – Standard for Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers.

IEEE Std C57.12.28™-2014 standard – Pad-Mounted Equipment - Enclosure Integrity.

IEEE Std C57.12.34™-2009 standard – Standard Requirements for Pad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers (2500 kVA and Smaller) - High Voltage: 34500GrdY/19920 Volts and Below; Low-Voltage: 480 Volt 2500 kVA and Smaller (issued in March 2005 - combines IEEE Std C57.12.22 and IEEE Std C57.12.26 standards).

IEEE Std C57.12.90™-2010 standard – Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers and IEEE Guide for Short-Circuit Testing of Distribution and Power Transformers.

IEEE Std C57.12.91™-2011 standard – Guide for Loading Mineral-Oil-Immersed Transformers.

NEMA TR 1-1993 (R2000) – Transformers, Regulators and Reactors, Table 0-2 Audible Sound Levels for Liquid-Immersed Power Transformers. 

NEMA 260-1996 (2004) – Safety Labels for Pad-Mounted Switchgear and Transformers Sited in Public Areas.

10 CFR Part 431 – Department of Energy – Energy Conservation Program: Energy Conservation Standards for Distribution Transformers; Final Rule.

Ratings

Rated Frequency

60Hz

Rated Voltage

2.5kV – 5.0kV – 8.7kV – 15.0kV – 25kV – 34.5kV

Rated Basic Impulse level

30kV – 45kV – 60kV – 75kV- 95kV – 110kV – 150kV – 200kV

Rated KVA

45kVA – 75kVA – 112.5kVA – 150kVA – 225kVA – 300kVA – 500kVA – 750kVA – 1000kVA – 1500kVA – 2000kVA – 2500kVA – 3000kVA –3750kVA –5000kVA –7500kVA –10000kVA (range may also be specified)