Substation Transformer

These heavy duty transformers are ideal for substation yards and power distribution line-ups.

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Maddox substation electrical transformer


A maddox substation transformer

    Maddox’s liquid-filled distribution substation, and power-class substation transformers are designed, built, and tested in accordance with the highest industry standards including NEMA, ANSI C.57, DOE, and IEEE as applicable. With a range of customizable features, Maddox substations can be configured to maximize performance, minimize potential arc flash exposure, and address environmental concerns. All designs can be supplied with full, or partial length air terminal chambers to make installation easy.

    Product Scope

  • kVA range: 300 kVA - 25,000 kVA base
  • Voltage range: Up to 69,000v

Technical Specs

Technical illustration of standard substation transformer

Standard specs

  • Type II non-PCB mineral oil (ONAN)
  • High-grade silicon-steel core
  • Aluminum windings (distribution class)
  • On-load tap changer
  • Reinforced carbon steel tank
  • Lifting lugs
  • Externally clamped high- and low-voltage bushings
  • Pressure relief valve
  • Pressure vacuum gauge
  • Liquid temp gauge
  • Liquid level gauge
  • Drain and sample valve
  • Schrader valve
  • Ground pads/lugs
  • Nitrogen blanket
  • 65 degree C rise

Optional upgrades

  • Environmentally friendly, high fire-point FR3 oil (KNAN)
  • Copper windings
  • On-load tap changer
  • ​Stainless steel tank
  • ​Gauges with contacts
  • ​Auxiliary control cabinet
  • ​Winding temperature indicator
  • ​Fan package (ONAN/ONAF)
  • ​Lid-mounted pressure relief device
  • ​Sudden pressure relay
  • ​Lightning arresters
  • ​55/65 degree C rise
  • ​Step-up solar and wind duty design
  • ​Electrostatic shielding
  • ​K-rated design
  • Primary load-interrupter switch

Get Started
We make it easy to get a quote and order a transformer. Follow the steps below to get started

Request a Quote

Call or fill out the form below to get a quote. Most quotes are turned around the same or next-day.

Place your order

Send us a purchase order, or give us a credit card number, and your dedicated customer service rep will send you an order confirmation and answer any questions you may have.

Receive your transformer

We’ll handle all transportation and logistics. Maddox has the shortest lead times in the industry so you can get the power on when you need it.

"We ordered transformers to use for our industrial equipment applications due to market shortages for our standard stepdown transformers. Delivery was incredibly quick and products look and operate without issue. Priced very well in comparison to other outlets - very happy to utilize Maddox in the future for our continued needs."

Todd Griffieth, ops manager

"I have purchased dozens of Maddox transformers, both low voltage dry-types and large reconditioned medium voltage units. Always great service and quality builds, with faster than industry standard lead-times."

Eric Raybould, distributor

"Quick delivery with helpful friendly staff. Great service and highly recommended. A great company to work with on all your transformer needs."

Austin Spiegel, project manager

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Maddox substation transformer ready to ship out