VPI (Vacuum Pressure Impregnated) Transformer with Insulation Class up to C
Backed by over 20 years of partnership with DuPont, CEEG VPI transformers combine industry-leading reliability with Class C (220°C) insulation. Designed for safety, resilience, and environmental protection, they offer high efficiency, superior overload, fully recyclable and zero harmful emissions, and NEMA 3R enclosure.
Cold-rolled, grain-oriented silicon steel with step-lap joints
Insulation Temperature
180℃, 220℃
Environment-Climate-Fire Class
F1, E2, C2 (KEMA)
Working Temperature
- 25℃ ~ 45℃
Relative Humidity
≤ 95%
Enclosure Options
NEMA 3R and others
Why Choose CEEG VPI Dry-Type Transformers?
• Insulation class up to C (220°C): Both main and auxiliary insulation use Class C materials.
• A trusted DuPont partner in insulation materials since 1999.
• Energy efficiency up to 99.26%.
• Environmentally friendly: fully recyclable and free from harmful emissions.
• Non-flammable and self-extinguishing.
• Excellent overload and short-circuit resistance: can operate at 120% load without fans; with fan cooling, short-time overload capacity exceeds 150%.
• Cabinet certified to AWS requirements, with load-bearing strength, heat dissipation, and rainproof performance compliant with NEMA 3R standards.
VPI Transformers, also widely known as Ventilated Dry-Type Transformers or Open-Wound Transformers, are high-performance power solutions that are particularly dominant in the North American market. Unlike standard models, CEEG VPI Transformers utilize advanced insulation technology to deliver superior safety and durability.
In 1999, CEEG pioneered the use of DuPont NOMEX® insulation paper in dry-type transformers, establishing our first VPI dry type transformer product line. This innovation led to a strategic partnership with DuPont in 2001. Today, our products are fully compliant with Transformer ANSI compliance and IEC60076 standards,making CEEG a top choice for global industries.
Our VPI step up transformers were the first in China to achieve Class C insulation certification by CSA and have successfully passed KEMA E2, C2, and F1 tests. Designed for efficiency, our VPI dry type transformer units delivered to Rio Tinto achieved a remarkable 99.26% energy efficiency—exceeding standard models by 8-15%—earning CEEG the "Most Innovative Supplier Award" in 2012.
Strategic Cooperation with DuPont
Rio Tinto's Recognised Supplier Certificate, KEMA Certificate, and CSA with Class C Insulation Certificate,
Application Scenarios
A. High-Density Public Spaces (Malls, Hospitals, Airports)
The Problem: Fire safety is paramount in crowded areas. Smoke and toxic fumes are the primary causes of casualties in fires.
The CEEG Solution: Our transformers use Nomex paper, which is self-extinguishing and flame-retardant. Even at 750°C, it releases no toxic halogens or smoke, maintaining over 92% visibility to aid safe evacuation.
B. Heavy Industry & Energy Sectors (Metallurgy, Petrochemicals, Data Centers)
The Problem: These sectors face uneven loads and frequent surges. The equipment must survive heat spikes that would destroy standard transformers.
The CEEG Solution:CEEG equips transformers with Class C (220°C) insulation using NOMEX® for both main and auxiliary windings. Class C insulation raises the temperature tolerance window, which directly improves resistance to thermal aging, short-duration overloads, and repeated heat spikes common in heavy industry and energy sectors.
C. Harsh Environments (Mines, Cement Plants, Nuclear Power)
The Problem: Airborne dust and radiation can degrade standard insulation or cause short circuits.
The CEEG Solution: The separated disc coil structure prevents dust accumulation. Furthermore, the multi-stage vacuum pressure impregnation process creates a sealed, dense insulation layer that is insensitive to dust and radiation, ensuring low-maintenance longevity.
D. Humid & Coastal Areas (Ships, Ports, Offshore Platforms)
The Problem: High humidity and salt spray can penetrate inferior insulation, causing short circuits and rapid corrosion.
The CEEG Solution: CEEG uses advanced Vacuum Pressure Impregnation (VPI) technology. Unlike simple dipping, our process uses alternating vacuum and pressure cycles to force the impregnating varnish deep into the coil windings. This cures into a solid, moisture-proof barrier that seals the conductors against salt fog and humidity, meeting strict marine anti-corrosion requirements.
VPI Transformer vs Cast Resin
Item
CEEG VPI Transformer (Nomex® Based)
Cast Resin Transformer (Epoxy Based)
Compliant Standards
IEC 60076-11, ANSI/IEEE C57.12.01
IEC 60076-11
Main Insulating Materials
DuPont NOMEX® Insulation Paper
Epoxy Resin
Thermal Insulation Grade
Class H (180°C) or C (220°C)
Class F (155°C) or H (180°C)
Heat Dissipation
Very High (Fan often not required)
Ordinary
Overload Capacity
Very Strong (High thermal margin)
Strong
Environmental Safety
High (Non-toxic, recyclable, smokeless)
Low (Non-biodegradable resin)
Coil Structure
Continuous Disc / Wire Wound
Solid Casting
Manufacturing Process
Vacuum Pressure Impregnation (VPI)
Vacuum Casting
Thermal Shock Resistance
Excellent (Flexible, does not crack)
Poor (Prone to cracking)
Moisture Resistance
Very Strong
Strong
Mechanical Properties
Resilient (High strength, never cracks)
Brittle (Hard but risks cracking)
Electrical Properties
Stable (Low dielectric constant, <5pC discharge)
Variable (Sensitive to air bubbles)
Manufacturing Molds
Not Required (Flexible production)
Required (High tooling cost)
After Service Life
Low recycle cost; no pollution
Difficult/Costly to recycle
Parameters Table
10kV SG(B)10 Dry Type Transformer
Rated high voltage：10kV,6kV
Rated low voltage：0.4kV
Vector Group：Dyn11 or Yyn0
Tapping Range：±2 x 2.5%, ±5%
Model
Impedance %
No Load Loss (W)
（145℃）Load Loss (W)
No Load Current %
Noise Level (dB)
Weight (kg)
SG10-100
4%
400
1370
1.8
43
675
SG10-125
4%
470
1610
1.6
43
720
SGB10-160
4%
540
1850
1.6
44
890
SGB10-200
4%
620
2200
1.4
44
920
SGB10-250
4%
720
2400
1.4
46
1050
SGB10-315
4%
880
3730
1
47
1410
SGB10-400
4%
980
4280
1
48
1565
SGB10-500
4%
1160
5230
1
49
1680
SGB10-630
4%
1340
6290
0.85
51
1800
SGB10-630
6%
1300
6400
0.85
51
1800
SGB10-800
6%
1520
7460
0.85
52
1930
SGB10-1000
6%
1770
8760
0.85
52
2355
SGB10-1250
6%
2090
10300
0.85
53
2940
SGB10-1600
6%
2450
12500
0.85
54
3540
SGB10-2000
6%
3050
15500
0.7
54
4050
SGB10-2500
6%
3600
18400
0.7
55
4790
SGB10-3150
6%
4030
19220
0.7
57
6215
10kV SGZ(B)10 Dry Type Transformer
Vector Group：Dyn11 or Yyn0
Tapping Range：±2 x 2.5%, ±5%
Model
Impedance %
No Load Loss (W)
（145℃）Load Loss (W)
No Load Current %
Noise Level (dB)
Weight (kg)
SGZB-250-10
4
720
2400
0.8
46
1400
SGZB-315/10
4
880
3730
0.7
46
1450
SGZB-400/10
4
980
4280
0.7
46
1965
SGZB-500/10
4
1180
5230
0.6
48
2145
SGZB-630/10
4
1340
6290
0.5
49
2320
SGZB-630/10
6
1300
6400
0.5
50
2205
SGZB-800/10
6
1520
7480
0.4
51
2635
SGZB-1000/10
6
1770
8760
0.4
51
2720
SGZB-1250/10
6
2090
10300
0.3
52
3225
SGZB-1600/10
6
2450
12500
0.3
53
4115
SGZB-2000/10
6
3050
15500
0.25
53
4365
SGZB-2500/10
6
3600
18400
0.25
54
5450
10kV SGB11 Dry Type Transformer
Rated high voltage：10kV,6kV
Rated low voltage：0.4kV
Vector Group：Dyn11 or Yyn0
Tapping Range：±2 x 2.5%, ±5%
Model
Impedance %
No Load Loss (W)
（145℃）Load Loss (W)
No Load Current %
Noise Level (dB)
Weight(kg)
SG11-100
4%
360
1310
1.6
42
875
SG11-125
4%
420
1550
1.4
42
920
SGB11-160
4%
480
1780
1.4
43
1090
SGB11-200
4%
560
2110
1.1
43
1120
SGB11-250
4%
640
2290
1.1
44
1250
SGB11-315
4%
790
3530
1
46
1610
SGB11-400
4%
880
4070
1
46
1765
SGB11-500
4%
1040
4970
1
47
1880
SGB11-630
4%
1200
5990
0.8
49
2000
SGB11-630
6%
1160
6070
0.8
49
2000
SGB11-800
6%
1360
7090
0.8
50
2130
SGB11-1000
6%
1590
8290
0.8
50
2555
SGB11-1250
6%
1880
9880
0.8
51
3140
SGB11-1600
6%
2200
11940
0.8
52
3740
SGB11-2000
6%
2720
14730
0.6
52
4250
SGB11-2500
6%
3200
17510
0.6
53
4990
Basic Parameters
Voltage Range
6 kV up to 24kV
Rated Capacity
Up to 30 MVA
Frequency
50 / 60 Hz
Impedance
4-6%
Tapping Range
±2*2.5%/±5%
Vector Groups
Dyn11 / Yyn0 / others on request
Core
Cold-rolled, grain-oriented silicon steel with step-lap joints
Insulation Temperature
180℃, 220℃
Environment-Climate-Fire Class
F1, E2, C2 (KEMA)
Working Temperature
- 25℃ ~ 45℃
Relative Humidity
≤ 95%
Enclosure Options
NEMA 3R and others
Why Choose CEEG VPI Dry-Type Transformers?
• Insulation class up to C (220°C): Both main and auxiliary insulation use Class C materials.
• A trusted DuPont partner in insulation materials since 1999.
• Energy efficiency up to 99.26%.
• Environmentally friendly: fully recyclable and free from harmful emissions.
• Non-flammable and self-extinguishing.
• Excellent overload and short-circuit resistance: can operate at 120% load without fans; with fan cooling, short-time overload capacity exceeds 150%.
• Cabinet certified to AWS requirements, with load-bearing strength, heat dissipation, and rainproof performance compliant with NEMA 3R standards.
VPI Transformers, also widely known as Ventilated Dry-Type Transformers or Open-Wound Transformers, are high-performance power solutions that are particularly dominant in the North American market. Unlike standard models, CEEG VPI Transformers utilize advanced insulation technology to deliver superior safety and durability.
In 1999, CEEG pioneered the use of DuPont NOMEX® insulation paper in dry-type transformers, establishing our first VPI dry type transformer product line. This innovation led to a strategic partnership with DuPont in 2001. Today, our products are fully compliant with Transformer ANSI compliance and IEC60076 standards,making CEEG a top choice for global industries.
Our VPI step up transformers were the first in China to achieve Class C insulation certification by CSA and have successfully passed KEMA E2, C2, and F1 tests. Designed for efficiency, our VPI dry type transformer units delivered to Rio Tinto achieved a remarkable 99.26% energy efficiency—exceeding standard models by 8-15%—earning CEEG the "Most Innovative Supplier Award" in 2012.
Strategic Cooperation with DuPont
Rio Tinto's Recognised Supplier Certificate, KEMA Certificate, and CSA with Class C Insulation Certificate,
Application Scenarios
A. High-Density Public Spaces (Malls, Hospitals, Airports)
The Problem: Fire safety is paramount in crowded areas. Smoke and toxic fumes are the primary causes of casualties in fires.
The CEEG Solution: Our transformers use Nomex paper, which is self-extinguishing and flame-retardant. Even at 750°C, it releases no toxic halogens or smoke, maintaining over 92% visibility to aid safe evacuation.
B. Heavy Industry & Energy Sectors (Metallurgy, Petrochemicals, Data Centers)
The Problem: These sectors face uneven loads and frequent surges. The equipment must survive heat spikes that would destroy standard transformers.
The CEEG Solution:CEEG equips transformers with Class C (220°C) insulation using NOMEX® for both main and auxiliary windings. Class C insulation raises the temperature tolerance window, which directly improves resistance to thermal aging, short-duration overloads, and repeated heat spikes common in heavy industry and energy sectors.
C. Harsh Environments (Mines, Cement Plants, Nuclear Power)
The Problem: Airborne dust and radiation can degrade standard insulation or cause short circuits.
The CEEG Solution: The separated disc coil structure prevents dust accumulation. Furthermore, the multi-stage vacuum pressure impregnation process creates a sealed, dense insulation layer that is insensitive to dust and radiation, ensuring low-maintenance longevity.
D. Humid & Coastal Areas (Ships, Ports, Offshore Platforms)
The Problem: High humidity and salt spray can penetrate inferior insulation, causing short circuits and rapid corrosion.
The CEEG Solution: CEEG uses advanced Vacuum Pressure Impregnation (VPI) technology. Unlike simple dipping, our process uses alternating vacuum and pressure cycles to force the impregnating varnish deep into the coil windings. This cures into a solid, moisture-proof barrier that seals the conductors against salt fog and humidity, meeting strict marine anti-corrosion requirements.
