Vegetable oil based dielectric coolant
In one aspect, the present invention provides a dielectric fluid for use in electrical equipment comprising a vegetable oil or vegetable oil blend. In another aspect the invention provides devices for generating and distributing electrical energy that incorporate a dielectric fluid comprising a vegetable oil or vegetable oil blend. Methods of retrofilling electrical equipment with vegetable oil based dielectric fluids also are provided.
1. A transformer comprising a housing, a core/coil assembly in the housing, and a dielectric fluid at least partially surrounding the core/coil assembly, wherein the dielectric fluid consists of:
at least one vegetable oils having a viscosity of between 2 and 15 cSt at 100° C. and less than 110 cSt at 40° C.,
at least one antioxidant compound, and
a petroleum-derived mineral oil, wherein the petroleum-derived mineral oil is less than 50% by weight of the dielectric fluid.
2. The transformer of claim 1 , wherein the antioxidant compounds are selected from the group consisting of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroxyquinone (TBHQ), tetrahydroxybutrophenone (THBP), ascorbyl palmitate, propyl gallate and alpha-, beta- or delta-tocopherol.
3. The transformer of claim 1 , wherein at least one of the vegetable oils is oleate modified.
4. The transformer of claim 1 , wherein the petroleum-derived mineral oil is less than 30% by weight of the dielectric fluid.
5. The transformer of claim 1 , wherein the petroleum-derived mineral oil is less than 20% by weight of the dielectric fluid.
6. A transformer comprising a housing, a core/coil assembly in the housing, and a dielectric fluid at least partially surrounding the core/coil assembly, wherein the dielectric fluid consists of:
one or more vegetable oils with a viscosity of between 2 and 15 cSt at 100° C. and less than 110 cSt at 40° C.;
at least one antioxidant compound selected from the group consisting of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroxyquinone (TBHQ), tetrahydroxybutrophenone (THBP), ascorbyl palmitate, propyl gallate and alpha-, beta- or delta-tocopherol;
at least one of a low temperature additive and an antimicrobial additive; and
a petroleum-derived mineral oil, wherein the petroleum-derived mineral oil is less than 50% by weight of the dielectric fluid.
7. The transformer of claim 6 , wherein the petroleum-derived mineral oil is less than 30% by weight of the dielectric fluid.
8. The transformer of claim 6 , wherein the petroleum-derived mineral oil is less than 20% by weight of the dielectric fluid.