Silicone oil as replacement fluid for PCBs in transformers

A brief critical review of the electrical, thermal and flammability properties of silicone oil for transformers is presented in comparison to the same properties for PCB and mineral oil. It is deduced that silicone oil is an acceptable substitute for PCBs. Despite a significantly lower fire resistance, silicone oil is not toxic and is compatible with traces of PCBs and mineral oil. It is therefore perfectly suited for the retrofilling of PCB contaminated transformers.