Development of knowledge and technology to implement retrofilling in power transformers using biodegradable or recycled fluids and fostering circular economy

Power transformers play a crucial role in electric power transmission and distribution systems, being both expensive and strategically important. Their prolonged efficient operation is essential to prevent long-term power outages.

With tens of thousands of transformers worldwide approaching the end of their typical 30-40-year lifespan, the question of recycling becomes significant. Remarkably, around 95% of a power transformer's materials could potentially be recycled.

Recognizing the importance of a circular economy, the European Commission adopted a Circular Economy plan in 2020, aiming to shift from a linear ""take, make, dispose"" model to a circular one where waste becomes a new resource. While the initial focus was on energy efficiency in transformers, the impact of materials is not negligible.

The upcoming revision of the eco-design regulation for transformers in 2023 will introduce new requirements on material efficiency.The proposed project will develop research on transformer retrofilling with alternative or recycled insulating liquids.

This technique is based on the replacement of the mineral oil of a transformer in service with a biodegradable and less-flammable fluid.

The procedure would lead to safer and more environmentally friendly transformers and could allow the application of higher loads, deferring the replacement of equipment in service.

However, the technique has not been sufficiently studied, it is needed to evaluate the impact of retrofilling on the operation of the transformer and to assess its economic and technical feasibility.

Project's researchers have applied the circular economy concept to power transformers in various ways during project definition:a) Evaluating the efficient use of materials throughout a transformer's life cycle (renewable or re-refined oils instead of conventional oils);b) Lifetime extension through dielectric and thermal design review and guidance on operation and maintenance.