Doubling down on CO2

By choosing NYTRO® BIO 300X for their transformers, utilities take steps towards sustainability. Apart from being bio-based, biodegradable, renewable, and recyclable, Nynas’ innovative transformer liquid also offers superior performance, further reducing carbon footprints.

Bio-based and with application-beating low viscosity, the new insulating liquid NYTRO® BIO 300X promises to improve the performance of transformers, helping utilities to achieve sustainability targets.

“Our ground-breaking and innovative insulating liquid offers several advantages. From a sustainability perspective, the advantages are two-fold. First, the bio-based liquid is produced from bio-based residue and by-products, giving it a negative footprint. Secondly, it offers performance benefits that reduce energy losses in transformers,” says Dr Gaia Franzolin, Marketing Director, Nynas Naphthenics.

Developed as an alternative to mineral insulating oil and ester liquids, and tested alongside such products, NYTRO BIO 300X shows off its superior qualities. Due to its very low kinematic viscosity, the new bio-based insulating liquid provides improved convective heat transfer in power transformers. A simulation of a 250 MVA transformer showed that, depending on the transformer design, significant temperature reductions of both windings and hot spot could be achieved.

“This means that a transformer filled with NYTRO BIO 300X will run at cooler temperatures, extending the life of the transformer or enabling its output to be uprated,” explains Carl Wolmarans, Technical Advisor Electrical Industry at Nynas.

The ultra-low viscosity also presents designers of transformers with optimisation and cost-saving opportunities. In a study, comparing NYTRO BIO 300X with a high-grade mineral insulating oil and ester liquids, the bio-based liquid allowed faster and more complete impregnation of the solid insulation.

“This ensures that there are no trapped voids or air bubbles in the transformer’s solid insulation, which are common causes of partial discharge in a transformer,” says Carl Wolmarans.

In addition, NYTRO BIO 300X shows better oxidation stability than existing mineral oils and vegetable-based insulating fluids in the market, making the bio-based liquid ideal for all transformer types, including not hermetically sealed, so called free-breathing transformers.

“Our bio-based liquid is also fully recyclable, and the same reclamation and re-refining technologies used today for mineral oils are equally appropriate for NYTRO BIO 300X,” says Gaia Franzolin.

Bio-based vs Biodegradable

• NYTRO® BIO 300X is both fully bio-based (ASTM D6866) and readily biodegradable (OECD 301). It is bio-based because it comprises material of biological origin, not including fossil material. Carbon-14 analysis shows that NYTRO® BIO 300X is made up of over 99 percent of bio-based carbon, making it a fully renewable hydrocarbon.

• In itself, this does not make the liquid biodegradable. Instead, NYTROΠ BIO 300X is biodegradable because it contains very pure, hydrocarbons of relatively low average molecular weight that are readily and effectively broken down by living organisms.

Benefits confirmed in Gothenburg

Using NYTRO® BIO 300X in one of three identical 40 MVA transformers in Gothenburg, Sweden enabled the utility company Göteborg Energi to test and evaluate several of the liquid’s benefits promoted by Nynas. Located in a sensitive water protection area in the city, the pilot transformer was easier to fill at low ambient winter temperatures thanks to the bio-based oil’s low viscosity. NYTRO® BIO 300X also exhibited better cooling properties, enabling around 10°C lower transformer temperature at the same output compared with identical transformers using alternative liquids.

Carl Wolmarans, Technical Advisor Electrical Industry at Nynas