Why are GAEP high voltage capacitors oil-filled?
Highly insulating oil is used to suppress partial discharges (corona), increase the dielectric strength, and increase the effective permittivity (dielectric constant) of the capacitor dielectric. Oil-filled film capacitors have high energy density in comparison with other types of capacitors used at high voltage, such as ceramic capacitors. Different types of oils are used with different types of capacitor dielectric and electrode designs.