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The publication in the summer of 2020 of an updated version of the electrical industry standard IEC 60296 marks an important step forward for recycled transformer fluids. The IEC standard offers revised specifications for liquids used in electrotechnical applications, such as the cooling of transformers and switchgear.
“To ensure that recycled liquids, originating from power equipment at the end of its life cycle, meet market requirements, the specifications focus on functional requirements irrespective of origin. Therefore, the updated standard is based on the oil’s performance rather than its source,” explains Bruce Pahlavanpour, Senior Technical Advisor, Nynas Naphthenics, and Chairman of the Technical Committee 10 (TC 10) of the International Electrotechnical Commission (IEC) responsible to IEC 60296.
With extensive experience from the transformer industry, Bruce Pahlavanpour is highly respected within the sector. He has been involved in the development of standards for many years, and was recently nominated and reelected by delegates from IEC’s 28 member states to continue chairing TC 10 for another three-year tenure.
“A wide range of industry representatives, including manufacturers of transformers, other electrical equipment and insulating liquids as well as utility operators, have participated in the revision process,” he points out.
The new specifications classify liquids as either type A or type B, reflecting the quality of the oil, where the best quality oil is recommended for critical transformers. Such type A liquid offers long service life and low stray gassing with high interfacial tension (IFT).
“High IFT is an indication of high quality and standard of the liquid handling and manufacturing. Low stray gassing is essential for normal operation. Related to thermal stress, not electrical, stray gassing should not be confused with gassing tendency” says Bruce Pahlavanpour.
An ordering designation and labelling scheme for the liquids is now a requirement in the new standard, see fact box.
“As a market leader, Nynas offers an extensive portfolio of high-performance transformer oils that already fulfil and outperform the specifications of the revised IEC standard,” says Koen Kempeneer, Global Market Manager Electrical Industry at Nynas.
The only Nynas Naphthenics products sold directly to endusers, transformer oils span three grades – Standard, High, and Super Grade, see product list. The company’s range also includes the recently introduced bio-based NYTRO® BIO 300X, a renewable high-performance transformer oil. Like all other Nynas products for the electrical industry, this latest addition is fully recyclable.
Four letter labelling
The revised IEC 60296 standard includes a new labelling scheme for insulating mineral oil. The labelling is based on identifying codes of four letters. The first letter relates to the equipment, the second states whether the oil is unused or recycled, the third determines the specification type, and the fourth letter informs the user of the type of antioxidant used in the oil.
For example, inhibited high grade recycled oil for transformers would be labelled TRAI, in accordance with the following:
First letter = Equipment [T = Transformer, S = Switchgear]
Second letter = Declaration [V = Unused (Virgin), R = Recycled]
Third letter = Type [A = Specification Type A, B = Specification Type B]
Fourth letter = Antioxidant [I = Inhibited, U = Uninhibited T = Trace inhibited]
A graded offering
Nynas offers an extensive range of transformer oils, fulfilling various technical and national standards, including three grades of IEC standard.
Standard Grade: NYTRO® Libra, NYTRO® Taurus
High Grade: NYTRO® Gemini X, NYTRO® Lyra X
Super Grade: NYTRO® 4000X, NYTRO® 10XN and NYTRO® BIO 300X
Bruce Pahlavanpour is a Senior Technical Advisor, Nynas Naphthenics. He joined Nynas in 2002. Having previously worked as Head of Insulating Fluids at National Grid in the UK, he chairs IEC, TC 10, and British Standards Institution (BSI), GEL 10.