Europe | November 12, 2025
KONČAR and Nynas introduce Croatia’s first transformer filled with fully renewable insulating fluid, marking a milestone in sustainable grid development.
Image for illustrative purposes
Croatia, Zagreb: An important step toward a more sustainable power grid has been taken in Croatia, where Nynas successfully delivered its bio-based transformer fluid, NYTRO® BIO 300X, for use in Zagreb’s electricity distribution system.
As part of its commitment to a low-carbon future, Nynas partnered with KONČAR – Distribution & Special Transformers (KONČAR – D&ST) and HEP ODS, Croatia’s national Distribution System Operator, to deploy the country’s first “green transformer.” A 630 kVA distribution transformer manufactured by KONČAR – D&ST was filled with NYTRO® BIO 300X – the first-ever use of this fully renewable insulating liquid in the Croatian market.
“The thermal and dielectric tests on the transformer filled with NYTRO® BIO 300X were successfully completed, and the unit is now fully operational,” said Ivanka Radić, responsible for transformer oils at KONČAR – D&ST. “All test results were within required limits, confirming the reliability and stability of this innovative fluid.”
Developed as part of Nynas’ portfolio of bio-based products, NYTRO® BIO 300X offers high oxidation stability, excellent cooling efficiency, and easy handling – making it a drop-in solution for operators seeking to reduce environmental impact without compromising reliability or performance.
“We are very proud to have been entrusted with this project by KONČAR – D&ST and HEP ODS Zagreb,” said Daniele Frustagli, General Manager Italy & the Balkans at Nynas. “This installation showcases the advantages of a fully renewable, bio-based hydrocarbon liquid that meets and exceeds IEC 60296 ed. 5 (2020) specifications.”
The initiative reinforces KONČAR – D&ST’s commitment to innovation and environmental responsibility. “This project reflects our ongoing efforts to explore more sustainable insulating fluids,” added Vanja Burul, President of the Management Board at KONČAR – D&ST. “We see great potential for further use of NYTRO® BIO 300X in future applications.”
Source: Nynas
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