You are here: Home » Products » Substation » Pad Mounted Substation » Three-Phase Pad-Mounted Transformer

Three-Phase Pad-Mounted Transformer

The Three-Phase Pad-Mounted Transformer is designed and manufactured in strict accordance with ANSI/IEEE C57.12.34 standards, featuring a compartmental-type, self-cooled, liquid-immersed construction. It is suitable for underground distribution systems with primary voltages up to 34.5kV and capacities up to 10,000 kVA.
This series is characterized by tamper-resistant enclosure, fully insulated high-voltage connectors, loop feed capability, and maintenance-free operation, making it an ideal choice for residential communities, commercial centers, industrial parks, and underground distribution networks in North American and global markets.


Availability:



Inquire Add to Basket

Technical Parameters

Applicable Standards

Standard	Description
IEEE Std C57.12.00	General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers
IEEE Std C57.12.34	Requirements for Pad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers (2500 kVA and Smaller)
IEEE Std C57.12.28	Pad-Mounted Equipment - Enclosure Integrity
IEEE Std C57.12.90	Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers
IEEE Std 386	Separable Insulated Connector Systems
10 CFR Part 431	DOE Energy Conservation Standards for Distribution Transformers

Main Technical Parameters

Parameter	Specification
Rated Capacity Range	45 kVA ~ 10,000 kVA
Primary Voltage	2.4kV ~ 34.5kV (GrdY/Delta)
Secondary Voltage	208Y/120V, 480Y/277V, 240V Delta, 480V Delta, 600V
Rated Frequency	60 Hz
Phase	Three-Phase
Cooling Method	OA / OA (Self-Cooled)
Insulation Medium	Mineral Oil / Natural Ester Oil (Optional)
BIL (Primary)	60kV ~ 150kV (depending on voltage class)
BIL (Secondary)	30kV (≤600V)
Temperature Rise	65°C (Top Oil)
Sound Level	Per NEMA TR 1
Enclosure Protection	Tamper-Resistant, Weather-Resistant
Finish Color	Munsell 7GY 3.29/1.5 (Pad-Mount Green)

Standard Ratings Table(12.47kV Class)

No.	Capacity (kVA)	HV (kV)	LV (V)	DOE Min. Efficiency
1	75	12.47 GrdY/7.2	208Y/120	99.03%
2	75	12.47 GrdY/7.2	480Y/277	99.03%
3	112.5	12.47 GrdY/7.2	208Y/120	99.11%
4	112.5	12.47 GrdY/7.2	480Y/277	99.11%
5	150	12.47 GrdY/7.2	208Y/120	99.16%
6	150	12.47 GrdY/7.2	480Y/277	99.16%
7	225	12.47 GrdY/7.2	208Y/120	99.23%
8	225	12.47 GrdY/7.2	480Y/277	99.23%
9	300	12.47 GrdY/7.2	208Y/120	99.27%
10	300	12.47 GrdY/7.2	480Y/277	99.27%
11	500	12.47 GrdY/7.2	208Y/120	99.35%
12	500	12.47 GrdY/7.2	480Y/277	99.35%
13	750	12.47 GrdY/7.2	208Y/120	99.40%
14	750	12.47 GrdY/7.2	480Y/277	99.40%
15	1000	12.47 GrdY/7.2	208Y/120	99.43%
16	1000	12.47 GrdY/7.2	480Y/277	99.43%
17	1500	12.47 GrdY/7.2	480Y/277	99.48%
18	2000	12.47 GrdY/7.2	480Y/277	99.51%

Outline Dimension Reference

Capacity (kVA)	Width (in)	Depth (in)	Height (in)
75-500	70	70	78
750-2500	90	106	78

Note: The dimensions above are for reference only. Specific dimensions can be customized according to customer requirements.

Product Features

Feature	Description / 说明
Compartmental-Type Construction	Separate compartments for transformer tank, HV termination, and LV termination, all integrated as a single tamper-resistant unit.
Loop Feed Capability	Standard design supports loop feed configuration with parking stands for each phase.
Separable Insulated HV Connectors	200A load-break bushing wells conforming to IEEE 386, externally replaceable.
Tamper-Resistant Enclosure	Recessed pentahead bolts, captive locking mechanism, and heavy-gauge steel construction per IEEE C57.12.28.
Corrosion-Resistant Finish	Semi-gloss Munsell 7GY 3.29/1.5 green coating with primer, minimum 3.0 mils thickness.
Crowned Roof Design	Roof is crowned to shed water and support up to 500 lbs distributed load.
External Taps	Two 2.5% taps above and below rated voltage (for 480V units).
Oil-Immersed Self-Cooled	OA cooling with mineral oil or optional natural ester oil.

Applications

Application	Recommended Capacity	Key Advantages
Residential Communities	75-1000 kVA	Low noise, tamper-resistant, underground feed
Commercial Centers	300-2000 kVA	Loop feed capability, high reliability
Industrial Parks	500-2500 kVA	Strong overload capacity, high efficiency
Underground Distribution	75-2500 kVA	Fully sealed, corrosion-resistant
Renewable Energy	500-5000 kVA	Adaptable to voltage fluctuations

Selection Guide

Capacity Selection

Load Power (kW)	Recommended Capacity (kVA)
≤ 60	75
60-90	112.5
90-120	150
120-180	225
180-240	300
240-400	500
400-600	750
600-800	1000
800-1200	1500
1200-1600	2000
1600-2000	2500

Primary Voltage Selection

System Voltage (kV)	Configuration	BIL (kV)
12.47	GrdY/7.2	95
13.2	GrdY/7.62	95
13.8	GrdY/7.97	95
24.94	GrdY/14.4	125
34.5	GrdY/19.92	150

Secondary Voltage Selection

Secondary Voltage	Configuration	Application
208Y/120	3-Phase, 4-Wire	Commercial buildings, mixed loads
480Y/277	3-Phase, 4-Wire	Industrial, commercial lighting
240 Delta	3-Phase, 3-Wire	Industrial motor loads
480 Delta	3-Phase, 3-Wire	Industrial equipment

Customization Services

Sline provides comprehensive customization services for three-phase pad-mounted transformers based on ANSI/IEEE standards:

Customization Option	Description
Capacity	45 kVA ~ 10,000 kVA
Primary Voltage	2.4kV ~ 34.5kV, Delta or GrdY
Secondary Voltage	208Y/120, 480Y/277, 240/480 Delta
BIL Level	Standard or upgraded per specification
Insulation Medium	Mineral Oil / Natural Ester Oil
Enclosure Color	Standard green or custom RAL color
Taps	2 × 2.5% above/below or custom range
Accessories	Load-break inserts, feed-thru inserts, lightning arresters
Special Environment	High altitude, coastal corrosion, seismic rating