In one aspect, the present invention provides a high voltage-high frequency electrical energy transformation apparatus comprising a frequency inverter capable of converting 60 Hz electrical energy into 40-100 KHz electrical energy; and a voltage transformer. The voltage transformer comprises a transformer housing; at least one soft magnetic core; a low voltage primary winding and a high voltage secondary winding; and a solid insulating material comprising polydicyclopentadiene. The solid insulating material is in contact with the high voltage secondary winding.