Sustainable insulation

Končar Instrument Transformers has been in business for more than 75 years. Over that time, the Croatian manufacturer of highand medium-voltage instrument transformers has steadily increased its global presence. The company currently has over 300 employees, serves around 100 markets worldwide and produces more than 4,000 high-voltage instrument transformers per year.

“We’re an engineering-driven organisation with a strong focus on demanding designs, tailored to the customer’s specification. I’d say we thrive as the level of difficulty increases, be it higher voltages, specific accuracy requirements, seismic design or other intricacies inherent to our industry,” says Dr Igor Žiger, Technical Director of Končar Instrument Transformers. Nynas has been Končar’s preferred mineral oil supplier for over a decade. The switch to and implementation of Nynas oils came very naturally at the time.

“They brought a very appealing mix of features to our production. Product quality, a broad portfolio, excellent service and support, and most importantly a partner-minded approach,” explains Igor Žiger. “We strive for that level of comfort and confidence with every supplier, so Nynas having that from the get-go speaks volumes.”

For the past eight years, Končar has been working diligently on implementing biodegradable dielectric liquids into its product portfolio under the _GREEN_ LINE_ moniker. Recently, the company completed routine, type and special tests on the first ever Station Service Voltage Transformer filled with a biodegradable liquid. The prototype unit is a 245 kV, 100 kVA transformer type VPT-245, impregnated with Nynas’ bio-based insulating liquid NYTRO® BIO 300X.

Implementing a new dielectric liquid is a complicated process involving dielectric performance, thermal performance, oxidation stability, material compatibility, cold-weather performance, internal arc performance, impact on internal processes, diagnostics and maintenance and so on. Končar compiled a specific testing sequence that runs through all these aspects and approves the liquid internally for commercial use.

“NYTRO BIO 300X really exceeded our expectations during the testing sequence. Looking at the technical data, we were expecting certain benefits, but its performance during dielectric ageing (lifetime expectancy tests) and cold weather tests is the best in the market, including conventional mineral oils,” notes Dr Žiger.

Končar’s strategic focus is to use biodegradable liquids exclusively, a process that started in late 2022 and is expected to be completed in 2027.

“The successful completion of this testing cycle is a significant piece of the puzzle to make our customers as comfortable with that initiative as we are. To succeed, we need their support, and to have that, they need our expertise, which is world-leading in this area,” says Davor Bakovic, CEO of Končar Instrument Transformers.

For Končar, Nynas plays a large part in their sustainability goals.

“I believe that the company’s biggest contribution is simply added value. Biodegradability, negative carbon footprint, oxidation stability and overall performance are a step up from existing mineral oils. We feel that it has been a while since such an evolutionary step happened in the instrument transformer industry,” explains Igor Žiger.

He makes a point of emphasising that the implementation of NYTRO BIO 300X was not sponsored or endorsed in any way by Nynas.

“The same applies for other biodegradable liquid products and their manufacturers. We want to remain as impartial as possible and have no restrictions on displaying results we gathered over the last several years.”

As for Nynas, the collaboration with Končar Instruments has been very fruitful, especially as the two companies share the goal of increasing the sustainability of their products and processes.

“Nynas supports customers to achieve their sustainability goals, such as global climate targets, implementation of green technologies and use of biodegradable products, based on our innovative and sustainable approaches,” says Ovidiu Nan, Nynas General Manager Central Europe.

“Owing to our specialist knowledge, we can provide a robust partnership in product development, and this goes hand in hand with the receptivity and interest of our customers, and our customers’ customers.”

Going forward, Končar anticipates a more intensive sharing of experience on NYTRO BIO 300X and other liquids, and an even higher level of commercial activity.

“We clearly see NYTRO BIO 300X as the necessary seasoning to the existing design of our Station Service Voltage Transformers, taking the product line to a new level of performance and sustainability," notes Igor Žiger.

“And we sincerely hope to keep the quality of relationship we have with Nynas, both on new developments and day-to-day logistics.”