Capacitor with insulation composition showing thermo-reversible oil-to-gel-transition

A method of treating a leak in a capacitor that includes:

• a container, comprising:
• at least one wound package of a metal foil and a polymeric insulating film, or of a metallized polymeric film, and
• an insulation composition,
• wherein the insulation composition comprises:
• a synthetic aromatic oil or a natural aromatic oil, and
• a polymer in a concentration of about 0.1 wt % to about 10 wt %,
• wherein the insulation composition is configured to undergo a thermo-reversible gelation below a gel-point temperature in the range from about 30° C. to about 90° C., the gel point being defined as the temperature at which the storage modulus G′ of the insulation composition is equal to the loss modulus G″ of the insulation composition, the method comprising:
• operating the capacitor, wherein the insulation composition is configured such that the insulation composition is in a liquid phase during standard operation of the capacitor, in case of a leak in the capacitor to the outside, spilling an amount of the insulation composition through the leak, and
• wherein the spilled amount undergoes a thermo-reversible oil-to-gel transition during or after the spilling when the spilled amount is exposed to the temperature outside the container.

A method of producing a capacitor that includes a container, comprising:

• at least one wound package of a metal foil and a polymeric insulating film, or of a metallized polymeric film, and
• an insulation composition,
• wherein the insulation composition comprises:
• a synthetic aromatic oil or a natural aromatic oil, and
• a polymer in a concentration of about 0.1 wt % to about 10 wt %,
• wherein the insulation composition is configured to undergo a thermo-reversible gelation below a gel-point temperature in the range from about 30° C. to about 90° C., the gel point being defined as the temperature at which the storage modulus G′ of the insulation composition is equal to the loss modulus G″ of the insulation composition, the method comprising:
• wrapping packages of the metal foil and the polymeric insulating film or of the metallized polymeric film, by insulating papers;
• heating the insulation composition;
• impregnating the wrapped packages, with the heated insulation composition, at a reduced pressure and an elevated temperature, to allow the heated insulation composition to impregnate the package, and letting the films swell for several hours,
• cooling the container with the packages and allowing the insulating composition to gel at room temperature, refill the insulation composition to compensate shrinkage, and
• sealing the container.