One or more electrical transformers comprising barrier structures for improved flashover resistance are provided herein. A barrier structure may be positioned between a higher voltage winding and a lower voltage winding, between the higher voltage winding and a core, or between two higher voltage windings of a multi-phase electrical transformer. The barrier structure may comprise a first material having a relatively lower permittivity value such as about 2.5 or less, which may provide improved flashover resistance. In an example, the barrier structure may comprise a second material having a relatively higher permittivity value such as about 2.5 or greater, which may provide improved puncture resistance. The barrier structure may comprise any number of layers of the first material and/or the second material
