Baden-Wuerttemberg power grid operator TransnetBW has announced the commissioning of Siemens' 420kV vegetable oil transformer at the Bruchsal-Kändelweg substation in Germany.
Siemens' new transformer links the 380kV extra-high voltage level with the 110kV grid of a subordinate distribution grid operator in the Bruchsal-Kändelweg substation plant near Karlsruhe.
The new transformer is insulated and cooled using vegetable oil rather than mineral oil. Siemens claims that its new transformer is the world's first vegetable oil transformer in the 420kV capacity range. Until now, the company has used vegetable oil insulation in power transformers with voltages of up to 123kV.
Insulating oil for the new environmentally friendly power transformer is produced solely from renewable plant resources. Vegetable oil has higher flashpoint and combustion point when compared to mineral oil.
In addition to this, vegetable oil is much less flammable and is completely bio-degradable when compared to mineral oil. Lower flammability of the vegetable insulating oil provides the transformer with a higher fire protection classification.
The new transformer, which weighs around 340t and contains 100t of insulating oil, can be installed and operated in water conservation areas or in zones subject to stringent environmental protection restrictions.
Siemens Energy Transformers business unit CEO Beatrix Natter said the properties of this vegetable oil are not only beneficial to the environment, but also offer the customer cost advantages over transformers cooled with conventional mineral oil.
"The bio-degradability of the insulating oil means that additional collecting vessels and separation systems are no longer required at the installation location, resulting in cost savings for these items," Natter said.
Image: Siemens commissions vegetable oil transformer in Bruchsal substation, Germany. Photo: courtesy of Siemens