Graded insulation cable construction, and method of overcoming stresses therein
AssigneeGeneral Electric Company
InventorsHarry C. Anderson, Burton T. MacKenzie, Jr., Maurice Prober, Nirmal Singh
Life of this patent
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Abstract
An electrical cable having an improved graded insulation which minimizes uneven electrical stresses caused therein by a lack of a symmetrical cable structure, and a method of overcoming disproportionate electrical stresses at interfaces intermediate the sections of a graded insulation for electrical cable.
Claims24
An electrical cable for high voltage service having a multi-layered, graded insulation which minimizes uneven electrical stresses at the interface of insulation gradations, comprising an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation consisting of at least two distinct contiguous of polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the insulation surrounding the electrical conductor having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, the specific inductive capacitance value of the innermost layer of polymeric insulation having the highest specific inductive capacitance surrounding the electrical conductor being about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous layer adjacent thereto being about 2.2 to about 3.0 and said specific inductive capacitance values being within a ratio of less than 1.4.
An electrical cable for high voltage service having a multi-layered, graded insulation which minimizes uneven electrical stresses at the interface of insulation gradations, comprising an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation consisting of two distinct contiguous layers of polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the insulation surrounding the electrical conductor having the highest specific inductive capacitance and the outwardly successive layer of polymeric insulation of the composite body of insulation having a decreased specific inductive capacitance value, the specific inductive capacitance value of the innermost layer of polymeric insulation having the highest specific inductive capacitance surrounding the electrical conductor being about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous layer adjacent thereto being about 2.2 to about 3.0 and said specific inductive capacitance values being within a ratio of less than 1.4.
An electrical cable for high voltage service having a multi-layered, graded insulation which minimizes uneven electrical stresses at the interface of insulation gradations, comprising an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation of at least one ethylene-containing polymer selected from the group consisting of polyethylene, blends of polyethylene and other polymers, and copolymers of ethylene and other polymerizable materials, and consisting of at least two distinct contiguous layers of said polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the insulation surrounding the electrical conductor having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, the specific inductive capacitance value of the innermost layer of polymeric insulation having the highest specific inductive capacitance surrounding the electrical conductor being about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous layer adjacent thereto being about 2.2 to about 3.0 and said specific inductive capacitance values being within a ratio of less than 1.4.
An electrical cable for high voltage service having an multu-layered, graded insulation which minimizes uneven electrical stresses at the interface of insulation gradations, comprising an elongated metal electrical conductor endlosed within a surrounding composite body of cross-link cured polymeric insulation of at least one ethylene-containing polymer selected from the group consisting of polyethylene, blends of polyethylene and other polymers, and copolymers of ethylene and other polymerizable materials, consisting of two distinct contiguous layers of said cured polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the cured insulation surrounding the electrical conductor having the highest specific inductive capacitance and the outwardly successive layer of polymeric insulation of the composite body of insulation having a decreased specific inductive capacitance value, the specific inductive capacitance value of the innermost layer of polymeric insulation having the highest specific inductive capacitance surrounding the electrical conductor being about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous layer adjacent thereto being about 2.2 to about 3.0 and said specific capacitance values being within a ratio of less then 1.4.
An electrical cable for high voltage electrical transmission service of at least about 69KV having a multi-layered, graded insulation which minimizes uneven electrical stresses at the interface of insulation gradiations, comprising an elongated metal electrical conductor enclosed within a surrounding composite body of cross-link cured polyethylene insulation consisting of at least two distinct contiguous layers of cured polyethylene insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the polyethylene insulation surrounding the electrical conductor containing a filler and having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, the specific inductive capacitance value at the innermost filled layer of polymeric insulation having the highest specific inductive capacitance surrounding the electical conductor being about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous layer adjacent thereto being about 2.2 to about 3.0 and said specific inductive capacitance values being within a ratio of about 1.2 to about 1.38.
A method of overcoming the detrimental effects of uneven electrical stresses at the interface of multi-layered, graded insulation in electrical cable for high voltage service comprising providing an elongated metal electrical conductor enclosed wihin a surrounding composite body of polymeric insulation consisting of at least two distinct contiguous layers of polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of insulation surrounding the electrical conductor having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, wherein said uneven stresses are attributable to a lack of crosssectional concentricity of the layers of graded insulation, comprising the steps of producing said innermost layer of polymeric insulation having the highest specific inductive capacitance of the composite insulation surrounding the electrical conductor with a specific inductive capacitance value of about 3.2 to about 3.8 and the contiguous layer adjacent thereto with a specific inductive capacitance value of about 2.2 to about 3.0 and with said specific inductive capacitance values in a ratio of less than 1.4.
A method of overcoming the detrimental effects of uneven electrical stresses at the interface of multi-layered, graded insulation in electrical cable for high voltage service comprising providing an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation consisting of two distinct contiguous layers of polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation having the highest specific inductive capacitance and the outwardly successive layer of polymeric insulation of the composite body of insulation surrounding the electrical conductor having a decreased specific inductive capacitance value, wherein said uneven stresses are attributable to a lack of cross-sectional concentricity of the layers of graded insulation, comprising the steps of producing said innermost layer of polymeric insulation having the highest specific inductive capacitance of the composite insulation surrounding the electrical conductor with a specific inductive capacitance value of about 3.2 to about 3.8 and the contiguous layer adjacent thereto with a specific inductive capacitance value of about 2.2 to about 3.0 and with said specific inductive capacitance values in a ratio of less than 1.4.
A method of overcoming the detrimental effects of uneven electrical stresses at the interface of multi-layered, graded insulation in electrical cable for high voltage service comprising providing an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation of at least one ethylene-containing polymer selected from the group consisting of polyethylene, blends of polyethylene and other polymers, and copolymers of ethylene and other polymerizable materials, and consisting of at least two distinct contiguous layers of said polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the insulation surrounding the electrical conductor having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, wherein said uneven stresses are attributable to a lack of cross-sectional concentricity of the layers of graded insulations, comprising the steps of producing said innermost layer of polymeric insulation having the highest specific inductive capacitance of the composite insulation surrounding the electrical conductor with a specific inductive capacitance value of about 3.2 to about 3.8 and the contiguous layer adjacent thereto with a specific inductive capacitance value of about 2.2 to about 3.9 and with said specific inductive capacitance value in a ratio of less than 1.4.
A method of overcoming the detrimental effects of uneven electrical stresses at the interface of multi-layered, graded insulation in electrical cable for high voltage service comprising providing an elongated metal conductor enclosed within a surrounding composite body of polymeric insulation of at least one ethylenecontaining polymer selected from the group consisting of polyethylene, blends of polyethylene and other polmers, and copolymers of ethylene and other polymerizable materials, consisting of two distinct contiguous layers of said polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of insulation surrounding the electrical conductor having the highest specific inductive capacitance and the outwardly successive layer of polymeric insulation of the composite body of insulation having a decreased specific inductive capacitance value, wherein said uneven stresses are attributable to a lack of cross-sectional concentricity of the layers of graded insulation, comprising the steps of producing said innermost layer of polymeric insulation having the highest specific inductive capacitance of the composite insulation surrounding the electrical conductor with a specific inductive capacitance value of about 3.2 to about 3.8 and the contiguous layer adjacent thereto with a specific inductive capacitance value of about 2.2 to about 3.0 and with said specific inductive capacitance values in a ratio of less than 1.4.
A method of overcoming the detrimental effects of uneven electrical stresses at the interface of multi-layered, graded insulation in electrical cable for high voltage electrical transmission service of at least about 69KV comprising providing an elongated metal conductor enclosed within a surrounding composite body of cross-link cured polyethylene insulation consisting of at least two distinct contiguous layers of cured polyethylene insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the polyethylene insulation surrounding the electrical conductor containing a filler and having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, wherein said uneven stresses are attributable to a lack of cross-sectional concentricity of the layers of graded insulation, comprising the steps of producing said innermost layer of polymeric insulation having the highest specific inductive capacitance of the composite insulation surrounding the electrical conductor with a specific inductive capacitance value of about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous layer adjacent thereto with a specific inductive capacitance value of about 2.2 to about 3.0 and with said specific inductive capacitance values in a ratio of about 1.2 to about 1.38.
An electrical cable for high voltage electrical transmission service of at least about 69KV having a multi-layered, graded insulation, comprising an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation consisting of up to four distinct contiguous layers of polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the insulation surrounding the electrical conductor having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, and wherein the specific inductive capacitance value of the innermost layer of polymeric insulation having the highest specific inductive capacitance of the polymeric insulation surrounding the electrical conductor is about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous relatively outward layer of polymeric insulation is about 2.2 to about 3.0, and said specific inductive capacitance values are in a ratio of less than 1.4.
An electrical cable for high voltage electrical transmission service of at least about 69KV having a multi-layered, graded insulation, comprising an elongated metal electrical conductor enclosed within a surrounding composite body of polymeric insulation consisting of up to three distinct contiguous layers of polymeric insulation having different specific inductive capacitance values arranged about the electrical conductor with the innermost layer of polymeric insulation of the composite body of the insulation surrounding the electrical conductors having the highest specific inductive capacitance and each outwardly successive layer of polymeric insulation of the composite body of insulation having a progressively decreased specific inductive capacitance value, and wherein the specific inductive capacitance value of the innermost layer of polymeric insulation having the highest specific inductive capacitance of the polymeric insulation surrounding the electrical conductor is about 3.2 to about 3.8 and the specific inductive capacitance value of the contiguous relatively outward layer is about 2.2 to about 3.0, and said specific inductive capacitance values of said contiguous layers are in a ratio of less than 1.4.
Dependencies are inferred from the claim text.