Substation Reliability Tip #11

Alternative Insulating Liquids

Mineral oil has long been the standard for a transformer’s dielectric insulating liquid, but mineral oil isn’t your only option. There are several dielectric insulating liquids in the market that are used for various applications, including silicone fluids, synthetic ester fluids, natural ester fluids, sulfur hexafluoride (SF6), high-molecular-weight hydrocarbons, and chlorinated fluids. You can learn more about them in this video.

The alternative insulating liquid that we are most drawn to at SDMyers is natural esters. In fact, many transformer owners and utility professionals are transitioning from mineral oil to natural ester fluid.

Natural ester liquids—like Cargill’s soybean-derived FR3 ® liquid—have earned growing recognition for their improved fire protection, resiliency, and notable environmental benefits. Alternative insulating liquids have been used for decades but are becoming more common and accepted industry-wide because of their advantages over mineral oil. FR3 offers higher fire and flash points to ease insurance challenges and has served as a substitute for fire suppression systems—even in indoor applications. In some cases, they may provide natural self-drying properties that help reduce the moisture in your transformer’s insulating paper, extending its reliable life.

Based on the data, you could experience significant benefits with natural esters:

17% average total cost of ownership savings
Up to 20% more load capacity than mineral oil
Up to 8x longer insulation life
2x higher flash and fire points than mineral oil
56x less CO2 emissions than mineral oil

With the ability to outperform mineral oil in overall cost savings, operating resiliency, transformer performance, fire safety, and environmental standards, natural ester liquids comply with IEEE and IEC standards and can be used in power and distribution transformers and certain substation equipment.

FR3 could be the better option for your transformer needs and provide immediate and long-term benefits. As an Authorized Service Partner of FR3 from Cargill, SDMyers is equipped to assist with a retrofilling process and help you see up to 10 years of additional life for your transformers.