Power Substation Transformers

All new PDM Power transformers are constructed of the highest quality materials and built to exacting engineering designs driven by Toshiba analysis software.
Utility Grade


All PDM oil-filled three-phase Power substation transformers have been designed, built and tested in accordance with industry standards to meet or exceed NEMA, ANSI C.57, DOE and IEEE as applicable. Featuring a wide range of customization, PDM’s Power transformers can be designed to match your application requirements, minimize exposure to potential arc flash and other safety concerns, while providing reliable power delivery to utility systems, data centers, and industrial distribution.

Designed to the DOE Energy Star efficiency standards.

Built and tested in accordance with NEMA, ANSI C57, and IEEE, as applicable.

UL® Listed to meet standards for sustainability and safety.
Detailed Features


Three-Phase Oil-Filled Power Transformers

Size (kVA)
From 10MVA up to 250MVA
Frequency (Hz)
60 Hz or 50 Hz
Cooling Class
ONAN/ONAF/OFAF and KNAN/KNAF/KFAF (Type II Mineral Oil, FR3, or Silicone)
Temperature Rise
55°C, 65°C, 55/65°C
5% up to 7.5%
Primary Voltage Class
35kV, 66kV, 110kV, 250kV, 350kV
Secondary Voltage
12kV, 25kV, 35kV, 66kV, 110kV


  1. High-grade silicon-steel core
  2. Windings: Aluminum or Copper
  3. No-Load Tap Changer
  4. Type II non-PCB mineral oil (ONAN)
  5. Reinforced carbon steel tank
  6. Removable radiators
  7. Lifting lugs
  8. Externally clamped high- and low-voltage bushings
  9. Pressure relief valve
  10. Pressure vacuum gauge
  11. Liquid temperature gauge
  12. Liquid level gauge
  13. Drain and sample valve
  14. Schrader valve
  15. Ground pads/lugs
  16. CT’s matched to ratio requirements
  17. Nitrogen blanket
  18. 55/65°C, or 65°C temperature rise


  1. Environmentally safe FR3 oil (KNAN, flammable-point >300°C)
  2. On-Load Tap Changer
  3. Stainless steel tank
  4. Gauges with contacts
  5. Auxiliary NEMA 3R/4 control cabinet and terminal box
  6. Protection and Control device
  7. Winding temperature gauge
  8. Fan package (ONAF, OFAF, or KNAF, KFAF)
  9. Lid-mounted pressure relief device
  10. Rapid pressure relay, with/without seal-in relay
  11. Lightning arresters
  12. Electrostatic shielding
  13. K-rated design to reduce harmonics
  14. Buchholz relay
  15. Primary load-interrupter switch
  16. Neutral Ground Resistor

Check out our complete line of Dry-type and Oil-filled Padmount transformers to support your load requirements.

Lead times are three (3) months for new Power transformers production and testing for up to 150MVA, depending on options and customizations selected. Lead times for up to 250MVA are 10 months due to components.

On site offloading, assembly and test supported through our partnership with Sunbelt Solomon. All products are covered by PDM’s Limited Warranty for five (5) years. Extended warranties are available, contact us to learn more!

Client Testimonials

We are honored to be the trust partner for so many clients.

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