UNDERGROUND TRANSMISSION SYSTEM EMPLOYING BARE CONDUCTORS SUPPORTED BY ELECTRICAL INSULATING FOAM
First Claim
1. A system for transmitting high-voltage electric currents from a point of generation to a point of utilization, comprising:
- a bare conductor carrying said high-voltage electric current; and
an underground installation through which said bare conductor runs to carry said current, said conductor being supported in said installation by a closed-cell foam surrounding said conductor and having electrical insulating gas entrapped therein of a high dielectric characteristic.
1 Assignment
0 Petitions
Accused Products
Abstract
High-voltage electric power is transmitted over long distances through bare conductors located underground and surrounded by a foam having insulating gas such as sulphurhexafluoride (SF6) entrapped in the cells thereof. During installation the conductors are supported by means of insulating strings hanging from crossmembers laid across the top surface of an installation ditch until the foam structure solidifies, at which time the insulating strings are cut and the earth backfilled. The solidified foam provides the means of support for the conductors, with the entrapped gases providing the necessary insulation.
32 Citations
10 Claims
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1. A system for transmitting high-voltage electric currents from a point of generation to a point of utilization, comprising:
- a bare conductor carrying said high-voltage electric current; and
an underground installation through which said bare conductor runs to carry said current, said conductor being supported in said installation by a closed-cell foam surrounding said conductor and having electrical insulating gas entrapped therein of a high dielectric characteristic.
- a bare conductor carrying said high-voltage electric current; and
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2. The system of claim 1, in which said underground installation also includes a conductive layer atop said foam for protecting said foam when said installation is backfilled and for reducing the voltage gradient otherwise produced at the top surface of said installation by the high-voltage electric currents passing through said conductor.
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3. The system of claim 2, in which there is also provided a penetration-resistant material along the sides and bottom of the underground installation to prevent destruction of said foam by external elements.
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4. The system of claim 3, in which said insulating entrapped gas iS sulfur hexafluoride.
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5. The system of claim 3, in which said foam is of an epoxy structure.
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6. A method of providing an underground transmission system for the carrying of high-voltage electric currents through a ditch or similar such enclosure from a point of generation to a point of utilization comprising the steps of:
- a. suspending a current-carrying bare conductor within said ditch by an insulating member;
b. surrounding said conductor with a closed-cell foam having electrically insulating entrapped gas therein which exhibits a high dielectric characteristic;
c. permitting said foam to solidify to support said conductor; and
d. covering said solidified foam with a backfill material to close said ditch.
- a. suspending a current-carrying bare conductor within said ditch by an insulating member;
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7. The method of claim 6, in which following step c. and preceding step d. there is included the additional step of putting down a conductive layer over said solidified foam to protect said foam when said ditch is backfilled and to reduce the voltage gradient otherwise produced at the top surface of said closed ditch by the high-voltage electric currents passing through said bare conductor.
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8. The method of claim 7, in which prior to step b. there is included the additional step of lining the bottom and at least a portion of the sides of said ditch with a penetration-resistant material.
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9. The method of claim 7, in which step b. comprises surrounding said conductor with a closed-cell foam having sulphurhexafluoride gas entrapped therein.
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10. The method of claim 7, in which step b. comprises surrounding said conductor with a closed-cell foam of an epoxy structure.
Specification