Ultra-high voltage transformer cooled with vegetable oil less prone to fires and coolant is biodegradable

TransnetBW, a grid operator in Baden-Württemberg, is beginning operating an environmentally friendly transformer that uses vegetable oil as a coolant.  The device will link the 380-kV ultra-high voltage level with the 110-kV grid in the Bruchsal-Kändelweg substation plant near Karlsruhe.  The transformer weighs just under 340 tons and contains 100 tons of vegetable oil.

Transformers are usually cooled and insulated with mineral or silicone oil.  These oils are harmful to the environment and highly flammable. Vegetable oils are less flammable and environmentally friendlier.   The types of vegetable oils are rapeseed, soy or sunflower oils, which are are biodegradable and have a much higher flashpoint.  This means that a vegetable oil transformer can be operated without additional protective equipment such as collecting tanks, even in zones with strict environmental requirements.  Vegetable oil transformers are much safer in densely populated residential areas.