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Specialist Materials for Industry and Science

Onshore Wind Energy

Onshore Wind Energy

Over the last decade wind energy has matured dramatically and today is one of our fastest growing sources of electricity. MIDEL 7131 has always played an important part in onshore wind applications because it offers advantages over other liquid-filled and dry type options.

A major benefit of using MIDEL 7131 is increased fire safety; the fire point of mineral oil in conventional transformers is approximately 170°C; whereas with MIDEL 7131 it is in excess of 300°C. Midel's fire safety may lead to a reduction in the requirements for additional fire protection.

Specifiers should be aware that Midel-filled systems are not as susceptible to damage from vibrations and harmonic frequencies as dry-type solutions. Dry-type transformers can also suffer from sensitivity to water, micro-cracks, temperature variations, load fluctuations and pollution. Furthermore, a dry-type transformer cannot be made as compact as a MIDEL 7131 filled system which is detrimental if space is limited.

Although reliability and fire safety are important, transformers should also be environmentally sound in this type of clean technology. In this respect, fluids such as mineral oil and silicone liquid cannot compare to MIDEL 7131 because it is readily biodegradable and non-water hazardous.

Benefits of MIDEL 7131 in Onshore Wind Transformers

Increased Fire Safety

High Performance

  • Robust and stable, conducive to lower levels of maintenance
  • High temperature performance allowing for compact transformer designs
  • Greater moisture tolerance than mineral oil, silicone liquid and natural ester
  • Excellent reliability, reputation as ‘fill and the forget fluid'
  • Lower no-load losses than cast resin transformers; reducing energy consumption in low wind conditions

Greater Environmental Protection

  • Readily biodegradable according to OECD 301 and fully biodegradable according to IEC 61039
  • Non-toxic and not harmful to aquatic life
  • Classified as non-water hazardous by UBA
  • RoHS compliant  

Excellent Customer Service

  • Multilingual commercial team
  • First-rate customer care
  • Continued technical support from the transformer fluid experts

For further information please visit our Documents or Contact Us.



  • Apiezon
  • Metrosil
  • Midel
  • Wolfmet

Products of M&I Materials Ltd.