P37.101: Transformer Life Management

Transformer of the future: Utility experience from field deployments: There is a growing list of emerging and novel transformer technologies being installed, and valuable lessons can be learned from these early field deployments. EPRI’s collaborative research approach provides significant opportunities to learn from the field. The shared learnings will help reduce the risks for the industry on selection and deployment of new technologies. Examples include resilient transformer concepts, flexible transformers (voltage, impedance etc.), transformers with novel fluids, and solid-state transformer components.

EPRI Power Transformer Guidebook (Copper Book) 2026 update: Each year EPRI publishes updates to the Copper Book to keep members up to date with the latest research, technology developments, and transformer standards. The guidebook is written for utility engineers and field staff, covering topics from specification to end-of-life assessment. In 2026, two valuable additions will be made: deeper guidance on dissolved gas analysis (DGA) sampling based on EPRI laboratory testing and a growing list of quick-reference, single-page summaries of key topics.

Technical webinars on the Transformer Guidebook: Multiple technical webinars based on chapters in the Transformer Guidebook are hosted each year. The webinar material is published for continued and convenient future access. Topics are selected to accelerate learning on key topics in the Transformer Guidebook (Copper Book).

Transformer online monitoring technologies: Laboratory testing to help members in specification development: In preparation for 2026, the laboratory capabilities for monitor evaluations have been expanded to allow for rapid and flexible testing of online bushing monitors. The results from the 2026 research provide valuable assistance in transformer monitor specification, interpretation, and adoption. A full 138-kV EPRI research substation also supports this research. EPRI laboratory test results are executed against a well-defined test protocol for online DGA monitors, online bushing monitors, online partial discharge monitors, and online temperature monitors. This unique approach allows for rapid answers on high-impact decisions that are then applied fleetwide in a utility.

Alternative fluids for transformers for increased ratings, extended service life, and reduced environmental impact: This research in 2026 aims to identify the characteristics that define the end of life for ester fluids. With several years of use, many chemical and physical properties of ester fluids can change significantly from the starting values. In many cases, the values of different ester properties can surpass the limits set for mineral-based oils. Even with such property changes, many users continue to use the ester fluids, not knowing how detrimental the changes in fluid could be to the operation and health of their transformer. Using accelerated aging systems, beneficial guidance could be obtained on what changes to chemical and physical properties (such as acid number, fire point, viscosity, etc.) mean to system operation and health. The goal of the results is twofold: to help set limits for acceptable operation of ester fluids; and to help users decide when to perform maintenance, a fluid change, and/or change the loading on the transformer.

New oil markers to aid power transformer diagnostics: In 2026, it is planned to explore the stability and dynamics of some newly identified oil markers by EPRI and others in the literature. It is known that new marker compounds are generated in the presence of oil and/or paper under different stresses (i.e., overheating, partial discharge, arcing). However, the longevity and interaction dynamics of the new markers with other components and chemicals inside a transformer are not known well, or sometimes not known at all. Data collected from a unique online marker detection system deployed by EPRI aims to provide some insights into new marker dynamics in a working transformer. Further exploration into new marker dynamics will be performed, providing the industry with enhanced value from oil samples and greater insights into transformer condition.