Power Transformer Design & Engineering Requirements

Your Prolec GE Waukesha’s Engineering Team has experience with a wide range of transformer configurations and special requirements, including:

  • Station / Substation transformers
  • Autotransformers (with or without a tertiary winding)
  • GSU (single or double low voltage winding), UAT, SST
  • Voltage regulators
  • Phase shifting transformers
  • Transformers with load tap changers (LTC)
  • Multiple winding transformers (more than two loaded windings)
  • Dual-voltage (series/multiple) high voltage (HV) or low voltage (LV)
  • Split winding transformers
  • Transformers with zigzag connections
  • Transformers with special overloading requirements
  • Transformers for use in unusual service conditions (listed in the IEEE/ANSI Standard C57.12.00-2006)


Prolec GE Waukesha’s design process utilizes an optimization strategy with the goal of providing the lowest total ownership cost (selling price + cost of losses) and best transformer design for each customer’s application. To achieve this goal, an experienced team of engineers most familiar with the customer’s specification is assigned to work on the project, which begins by accessing design data from one of the industry’s largest computerized libraries of power equipment configurations. To optimize materials, production scheduling and delivery, hundreds of alternative core and coil designs may be reviewed for each proposal, allowing Prolec GE Waukesha’s engineers to select the optimum design based on each customer’s individual needs.

Optimum transformer design occurs when a balance is achieved between the costs of

  1. Variable commodities, such as steel, copper and oil
  2. Losses
  3. Manufacturing labor hours
  4. Plant capability constraints
  5. Shipping constraints

Our goal is to design and deliver a transformer with a performance specification that meets or exceeds each customer’s requirements.


Waukesha® transformers are designed and manufactured in accordance with the latest IEEE , NEMA, ANSI or IEC standards, as well as the quality standards of ISO 9001:2015. Advanced engineering tools and software are also utilized:

Electrical Engineering Software

  • Transformer design programs — to calculate impedance, losses, thermal performance, etc.
  • Technical Advisories — online design documentation containing design rules for building a transformer; revision level controlled under ISO 9001:2015 guidelines
  • Impulse distribution program — analyzes dielectric stresses on windings during transformer impulse tests
  • Short circuit programs — analyze forces on windings and structures during a short circuit employing Finite Element Analysis (FEA) or boundary element methods
  • Ansys Maxwell – 2D /3D Electrostatic & Electromagnetic Analysis with circuit coupling
  • Ansys Mechanical – Static Structural and Steady State / Transient Thermal Analysis
  • Cooling design programs — calculate transformer cooling requirements and overload performance
  • Optimization program — determines the lowest total ownership cost (TOC) design for each customer’s application

Mechanical Engineering Software

  • PTC-CREO® — true 3D modeling program with fully parametric models; design inputs from an SQL database with outputs directly to our MRP system and to manufacturing machine centers
  • CREO-SIMULATETM — FEA application used for new product development
    NOTE: PTC-CREO® 3D CAD software and CREO-SIMULATETM FEA software are registered trademarks of Parametric Technology Corporation, Needham, MA, USA. For additional information, please visit www.ptc.com
  • Technical Advisories — online design documentation containing design rules for building a transformer; revision level controlled under ISO 9001:2015 guidelines
  • Tank sizing programs — customized tank sizing programs for medium power and large power transformers automatically set tank size and bushing locations for every design


When changes are required to the design, Prolec GE Waukesha’s Engineering Team works closely with our Manufacturing and Quality departments to continually provide up-to-date computerized Engineering Change Orders (ECOs). To help achieve consistent quality, work process flows are governed by stringent ISO 9001:2015 guidelines. This teamwork helps provide components and assemblies that are manufactured to each customer’s specifications with the most current engineering information.