MIDEL 7131 is the world’s leading biodegradable synthetic transformer fluid – the only synthetic ester with FM approval.

It is used in power and distribution transformers, including sealed and free-breathing designs, to deliver fire safety, environmental protection and cost savings. In addition to mainstream applications, MIDEL 7131 is also used in demanding sectors including Renewable Energy, Traction, Mining, Marine, Underground and for Retrofilling.

First developed by M&I Materials in the 1970s, MIDEL 7131 is the no-compromise alternative to mineral oil. Its success is proven up to 433kV and is endorsed by its use in 70% of the world’s countries.

MIDEL 7131 is a biodegradable synthetic ester dielectric liquid designed to provide an alternative to mineral oil, silicone liquid and dry-type transformers.

MIDEL 7131 has a high fire point (316˚C), significantly increasing the fire safety of your transformers and reducing the need for fire protection equipment.

MIDEL 7131 is readily biodegradable, avoiding environmental damage should leakage occur and enabling reductions in containment measures.

MIDEL 7131 has an extremely low pour point of -56˚C, making it a highly effective solution in colder climates.

MIDEL 7131 has exceptionally high moisture tolerance. This characteristic enables the extension of cellulose insulation life.

MIDEL 7131 is currently used in a wide range of transformer applications and is proven up to 433kV. Perfectly suited for non free-breathing and free-breathing transformers (due to its excellent oxidation stability) located indoors or outside.

MIDEL 7131 offers the ability to safely increase transformer loading or reduce transformer size.


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