USA: Replacing mineral oil insulated transformers with natural ester fluid units to help remodel power grid infrastructure and prevent fires.

As of October 2020, 74 large fires have burned 4.2 million acres in the United States and more than 45,000 wildfires have burned just over 8 million acres this year. Changes in our climate, outdated infrastructure and other factors will continue to increase fire risk in all areas of the country. As this is becoming the new normal year after year, it is time to rethink how improvements to power grid infrastructure can help prevent fires from fuelling beyond a contained incident into a catastrophic event. One such solution is replacing more mineral oil insulated transformers with natural ester fluid units.

Originally developed as a less flammable insulating fluid to improve the fire safety of transformers, natural ester is the market leader among alternatives to conventional mineral oil, used in over 2.5 million transformers globally.

With a fire point at 360 oC, the highest among the currently used alternative liquids, natural ester is the best-in-class less flammable insulating fluid, with no pool fire ever reported in any transformers filled with it. With a significantly higher fire point, natural ester is ideal for on-site retrofilling of existing transformers, tolerating a residual content of mineral oil inside the transformer as high as 7 % without any reduction of the fire point.

While mineral oil remains an upfront low-cost option for transformer fluid, this initial lower cost must be considered alongside its drawbacks of a low flashpoint, low fire point, and higher likelihood of burning in a fault condition. This is coupled with mineral oil’s inferior environmental performance as a fossil combustible, potentially hazardous in both soil and water.

The possible evolution of distribution utility policy with regards to transformer oils is to move towards standard usage of natural ester oils such as Cargill FR3®. Fire risk mitigation presents a major driver for this adoption, and the additional transformer lifetime extension and enhanced loading capacity provide additional economic incentives.

Pacific Gas and Electric, a major power investor-owned in California, has seen success in switching from traditional mineral oil transformers to natural ester. As safety and reliability concerns continue to grow for the region, natural ester is one step the cooperative feels will help reduce risk.

Furthermore, outside of reducing risks during fires, natural ester also reduces the environmental impact in the event of spills due to its biodegradability and non-toxic properties. With increasingly stringent health, safety and environmental regulations, natural ester is an ideal choice for utilities proactively planning for the future. 

Source: Utility Products