New Generation Solid Insulation for Traction Transformers

Train manufacturers, whose focus is on sustainable mobility and reduced operating costs, are looking for transformer manufacturers to evolve onboard traction transformers to meet their development goals. Traction transformer energy efficiency improvements are primarily driven by weight reduction, resulting in reduced losses, lower operating costs, and increased safety.

Weidmann works closely with leading global traction transformer suppliers to deliver high-performance solid insulation solutions tailored for traction transformer applications. Our materials are engineered to support maximum reliability, long-term life, and optimized cost for efficient and fault-free rail operation.

Traction transformers, which typically contain high-temperature insulation materials in their transformer windings, are optimized for weight, efficiency, safety, and cost. The key challenge is balancing those design parameters. Enter INSULutions DPE (Diamond Pattern Enhanced), an innovative engineered paper exclusively from Weidmann.

High-temperature INSULutions DPE Paper

Thermal class describes an insulation system’s temperature rating in liquid-immersed transformers. It is defined as the maximum allowable (continuous) hottest spot winding temperature plus 10°C to account for “normal life expectancy loading,” which considers daily and annual load cycles.

The highest thermal class insulation systems in liquid-immersed transformers are based on aramid solid insulation. However, due to the very high cost of aramids, there is a strong case for another high-temperature, solid insulation with a similar price point to Thermally Upgraded Kraft (TUK) paper, but with a higher thermal class.

INSULutions DPE paper was developed by Weidmann as a 100% cellulose-based, cost-effective solid insulation material with a thermal class between TUK paper and aramids. Using special cellulose fibers and production technologies, INSULutions DPE is rated with a thermal class of 130°C in mineral oil and 140°C in natural ester liquid, an increase of 25°C greater than Kraft paper and 10°C greater than TUK paper.

A traction transformer insulation system containing Weidmann INSULutions DPE paper provides several advantages:

• Significantly reduced cost compared to aramid solid insulation
• Reduced size, weight, and losses vs. TUK paper
• Long-term, safe operation

INSULutions DPE Traction Transformer Insulation Considerations

Onboard traction transformers used to supply power to railway vehicles such as high-speed trains and electric locomotives must comply with stringent vehicle specifications, including placement, weight, and dimensions. The insulation system of modern traction transformer windings must be optimized for initial and total ownership cost, reduced size and weight, and enhanced thermal stability and thermal resistance to improve dielectric performance and facilitate faster drying and liquid impregnation rates while maintaining excellent mechanical properties against mechanical stresses.

INSULutions DPE is made with 100% cellulose fibers, meaning it is a highly sustainable insulation solution, yet priced competitively to Kraft and TUK papers. Compared to aramid insulation materials, INSULutions DPE is an efficient and cost-effective solution for traction transformer insulation applications. Compared to TUK paper, the higher thermal class of INSULutions DPE allows a reduction in the size of the core and coil, helping to build smaller, lighter, and more energy-efficient, lower-loss transformers.

The Infrastructure of Tomorrow

Weidmann is committed to advancing rail electrification by providing tailor-made insulation solutions that support innovation, enhance traction transformer performance, and contribute to the future of sustainable transportation. High-temperature INSULutions DPE paper from Weidmann can help move the rail industry towards a more efficient and sustainable future.

Explore Weidmann’s full range of insulation solutions for traction transformers.