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Medium-voltage transformers

Substation transformer

Eaton’s Cooper Power series substation transformers are built with unprecedented quality and attention to detail, meeting a vast range of customer specifications and applications. Designed for both new installations and retrofit solutions, these substation transformers  are optimized to perform in the most rigorous sectors of industry and are designed to last. Transformers can be filled with FR3 fluid, offering fire safety and extended life or with conventional mineral oil for common applications.

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Substation transformers-unit and open types catalog Substation transformer installation, operation and maintenance instructions and parts replacement information
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Base rating
300-12,000 kVA
Secondary voltage
208-15,000 V (25 kV available upon special request)
Primary voltage
2400-46,000 V, Delta or Wye

Core features

  • Available with cover-mounted or sidewall-mounted bushings for connections to primary and/or secondary switchgear
  • Constructed with a wide range of core steels and winding conductors to optimize efficiency versus cost
  • Flexible core/coil and tank construction enable dimensional requirements to be met
  • Transformers filled with FR3 fluid may be used in indoor applications and provide unique fire safety and environmental advantages, including extension of insulation life
  • All units meet applicable ANSI, IEEE and NEMA standards, as well as NEC, DOE and CSA specifications

Combining flexibility with the highest quality manufacturing

Designed to meet exact customer specifications, Eaton’s Cooper Power series substation transformers fulfill a variety of commercial, industrial and utility needs for both indoor and outdoor applications.

The safer, environmentally friendly choice

When biodegradable FR3 high-fire-point dielectric fluid is utilized, transformers provide enhanced fire safety and environmental benefits and increase equipment longevity.

Global recognition

Eaton's Cooper Power series substation transformers can be certified in full by third party nationally recognized testing laboratories including FM and UL/cUL and can be built for Class 1 Division 2 locations.

Save space and reduce equipment coordination

Close-couple medium-voltage liquid-filled transformers with low and medium-voltage assemblies in a streamlined unit substation design.
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Specifications

Ratings

Base kVA
 300 kVA to 12,500 kVA
Primary voltage*
 2400 V to 46,000 V
Secondary voltage
 120 V to 24,940 V
Basic Impulse Level (BIL)
 30 kV to 250 kV
Fluids
 FR3 or mineral oil
Additional forced-air ratings
 +15%, +25%, +33% to base kVA

*Consult factory for higher primary voltages

 

 

Standards

ANSI/IEEE
 C57.12.00 and C57.12.36
CSA
 C88-M90
NEMA (sound level)
 NEMA TR-1
Third-party approval/recognition
 FM Global (Indoor & Outdoor), UL/cUL – available for most ratings

Enclosure

Layout
 Cover or sidewall terminals
Air terminal chambers
 Three-point latching and padlock system with recessed penta-head bolts
Close-coupling
 Standard flanges and throats
Specialty coordination
 Custom gear connections
Enclosure integrity
 Meets or exceeds ANSI/IEEE C57.12.28 and C57.12.29 (if stainless construction)
Material 
 Mild or stainless steel (304L)
Enclosure environment
 Indoor and outdoor

Key features

Distribution/small power transformer
 Substation style transformers
Install location 
 Indoor and outdoor
Power direction 
 Step-down and step-up
Specialty designs
 Motor loads, harmonics, rectifier duty, K-factor and more
Download Links
  • Commercial and industrial medium-voltage electrical distribution products brochure
    This brochure outlines Eaton’s Cooper Power series broad commercial and industrial medium-voltage transformer, switchgear, fuse, sectionalizer, switch, regulator, tool, OEM equipment, cable accessory, lightning arrester, power capacitor and recloser offerings.
    (PDF 2 MB , 01/24/2023)
  • Copper vs. aluminum conductor product aid
    This brochure explains that Eaton’s Cooper Power series aluminum-wound coils use the same thermal, dielectric and mechanical performance requirements as its copper-wound coils and that in pad-mounted and substation designs, aluminum-wound transformers and copper-wound transformers serve their loads equally well.
    (PDF 83 KB , 11/01/2016)
  • Substation transformers-unit and open types
    This catalog provides features and ordering information for Eaton’s Cooper Power series substation transformers which are designed to meet a wide variety of customer specifications.
    (PDF 874 KB , 02/21/2025)
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