Capacitively graded modular pothead for h-v cable

Claim 2

A capacitively graded electrically insulating device comprising an elongated tubular flexible insulating resin sleeve and including a shaped portion at one end formed of the same resin as the balance of the sleeve and chemically bonded thereto and having electrically conducting particles therein to provide measurable conductivity and constituting an electrical stress relief assembly, a series of alternated contacting flat conducting and insulating rings surrounding said sleeve and constituting a multiplicity of series connected capacitors, a tubular outer insulator surrounding said rings, a H-V cable having a grounded sheath, insulation within said sheath, and a conductor within said insulation, said cable having an end portion with the sheath removed extending through said sleeve and having its conductor bared beyond the end of said sleeve, means electrically connecting said sheath to a conducting ring at one end of said series of rings and means electrically connecting said bared conductor to a conducting ring at the other end of said series of rings.

Claim 3

A device as defined in claim 1 in which the Outer insulator and the in-built series connected capacitors are formed of a plurality of like modules.

Claim 4

A device as defined in claim 1 in which the shaped end portion of said sleeve has a cylindrical outer surface, and a metal sleeve in which said end portion is received.

Claim 5

A device as defined in claim 3, the shaped end portion of said insulating sleeve being tightly embraced in said metal sleeve in sealing relation.

Claim 6

A capacitively graded electrically insulating device comprising a tubular outer insulator through which the end of a H-V cable extends with its ground sheath stripped away throughout said device and its insulation continuous except for the end of the cable at the end of the device where the conductor is bared, a series of flat alternated contacting insulating and conducting rings within said insulator, and spaced radially outwardly from the cable portion therewithin, the end rings of said series being metal rings, a hollow cap closing the outer end of said device, the space within said cap serving as an expansion chamber for oil in the space between the H-V cable and said series of rings, means electrically connecting the metal ring at the outer end of said series to the bared conductor end, an insulating seal surrounding the cable at the inner end of said device and sealingly engaging the exposed cable insulator thereat, a metal sleeve supporting the inner end of said outer insulator, surrounding said insulating seal and electrically connecting the adjacent conducting end ring of said series to the end of the ground sheath on the H-V cable.

Claim 7

A capacitively graded electrically insulating device comprising a tubular outer insulator through which the end of a H-V cable extends with its ground sheath stripped away throughout said device and its insulation continuous except for the end of the cable at the end of the device where the conductor is bared, a series of flat alternated contacting insulating and conducting rings within said insulator, and spaced radially outwardly from the cable portion therewithin, the end rings of said series being metal rings, a hollow cap closing the outer end of said device, the space within said cap serving as an expansion chamber for oil in the space between the H-V cable and said series of rings, means electrically connecting the metal ring at the outer end of said series to the bared conductor end, an insulating seal surrounding the cable at the inner end of said device and sealingly engaging the exposed cable insulator thereat, a metal sleeve supporting the inner end of said outer insulator, surrounding said insulating seal and electrically connecting the adjacent conducting end ring of said series to the end of the ground sheath on the H-V cable.

Claim 8

A device as defined in claim 5 in which the portion of said insulating seal within said metal sleeve comprises a shaped measurably conducting end portion cooperating with the adjacent structure to form an electrical stress relief assembly.

Claim 9

A device as defined in claim 5, which comprises an insulating sleeve having its internal diameter dimensioned to be spaced radially outwardly from the insulation on said cable to provide a space for the reception of oil therebetween.

Claim 10

A module for assembly with a plurality of like modules to form a capacitively graded electrically insulating device, each module comprising a series of flat alternated insulating and conducting rings in end contact with each other constituting a multiplicity of series connected capacitances, an outer annular insulating body formed of arc and track resistant resin permanently secured around said series of alternated insulating and conducting rings and surrounding said series from end to end, the outer surface of said body being shaped to form with like modules an outer surface of smoothly curved axially spaced circular ribs, the rings at the ends of each module being metal rings having mechanical connecting means integral therewith effective to hold the adjacent modules in firm mechanical and electrical contact with each other.

Claim 11

A module for assembly with a plurality of like modules to form a capacitively graded electrically insulating device, each module comprising a series of flat alternated insulating and conducting rings in end contact with each other constituting a multiplicity of series connected capacitances, an outer annular insulating body formed of arc and track resistant resin permanently secured around said series of alternated insulating and conducting rings and surrounding said series from end to end, the outer surface of said body being shaped to form with like modules an outer surface of smoothly curved axially spaced circular ribs, the rings at the ends of each module being metal rings having mechanical connecting means integral therewith effective to hold the adjacent modules in firm mechanical and electrical contact with each other.

Claim 12

A module as defined in claim 8 in which the connecting means comprises bayonet joints.

Claim 13

A module as defined in claim 9 in which the bayonet joints comprise a pair of metal plates having flat surfaces in inter-engagement and connected together, one of said plates being apertured and grooved on the side thereof in engagement with the other of said plates to form a completely enclosed Faraday cage for the reception of a headed pin constituting the other part of the bayonet joint.

Claim 14

A module as defined in claim 8 in which the mechanical connecting means at one end of each module comprises an annular flange at the inner edge of the ring on which it is provided and having its inner surface forming a smooth continuation of the inner surface of said ring and having its outer surface threaded, the mechanical connecting means at the other end of each module comprising an internally threaded flange spaced outwardly from the inner edge of the ring on which it is provided by the effective thickness of the flange at the other end of said module, and dimensioned such that an assembly of Such modules forms an outer insulator assembly having a smooth continuous uninterrupted surface confronting the H-V cable therein.

Claim 15

A module as defined in claim 11 in which said flanges are spaced from the outer edges of said ring to form when assembled together an outwardly open cylindrical recess, the outer annular insulating body of each module having an inwardly extending annular flange received in said recess in assembly.

Claim 16

A module as defined in claim 12 in which one of the end rings of each module is provided with a circular channel located outwardly of the threaded flange thereon, an O-ring in said channel, said O-ring being dimensioned to provide an effective seal while permitting engagement between the end surface of outwardly threaded flange and the adjacent surface of the end ring of the adjacent module.

Claim 17

A capacitively graded electrically insulating device comprising an elongated series of end-contacting alternated flat insulating and conducting rings constituting a series connected group of capacitances, an insulating sleeve within said capacitances, a generally tubular insulating body surrounding said capacitances, said insulating rings being formed of a plastic resin material provided with a ceramic filler selected to produce a high dielectric constant the value of which increases with temperature.

Claim 18

A capacitively graded electrically insulating device comprising an elongated series of end-contacting alternated flat insulating and conducting rings constituting a series connected group of capacitances, an insulating sleeve within said capacitances, a generally tubular insulating body surrounding said capacitances, said insulating rings being formed of a plastic resin material provided with a ceramic filler selected to produce a high dielectric constant the value of which increases with temperature.

Claim 19

A capacitively graded device as defined in claim 14 in which the dielectric material has a non-linear relationship between impressed voltage and resulting current which upon increase in voltage produces a current greater than the current value which would be produced if the current-voltage characteristic was linear.

Claim 20

A device as defined in claim 14 in which said device is formed of a multiplicity of end connected modules, each of which comprises a multiplicity of said rings, an insulating sleeve with said rings, and an outer tubular insulating body surrounding said rings.

Claim 21

A device as defined in claim 16 in which the rings at the ends of each module have mechanical connection means formed integral therewith.

Claim 22

A device as defined in claim 14 in which the plastic of which said rings are formed is selected from the group consisting of epoxy, polyester, silicone, polysulfide, urethane, and combinations thereof; and polyolefin and ABS (Acrylonitrile butadiene styrene).

Claim 23

A device as defined in claim 14 in which said ceramic filler is selected from the group consisting of niobates, silicates, tantalates and zirconates of barium, bismuth, lead and strontium, and oxides of lanthanum and titanium.

Claim 24

A capacitively graded electrically insulating device comprising an elongated end-contacting series of alternated insulating and conducting rings constituting a series connected group of capacitances, an insulating sleeve within said capacitances, a generally tubular insulating body surrounding said capacitances, said insulating rings being formed of a plastic resin material provided with a ceramic filler selected to produce a high dielectric constant and having a non-linear relationship between impressed voltage and resulting current which upon increase in voltage produces a current greater than the current value which would be produced if the current-voltage characteristic was linear.

Claim 25

A capacitively graded electrically insulating device comprising an elongated end-contacting series of alternated insulating and conducting rings constituting a series connected group of capacitances, an insulating sleeve within said capacitances, a generally tubular insulating body surrounding said capacitances, said insulating rings being formed of a plastic resin material provided with a ceramic filler selected to produce a high dielectric constant and having a non-linear relationship between impressed voltage and resulting current which upon increase in voltage produces a current greater than the current value which would be produced if the current-voltage characteristic was linear.

Claim 26

A capacitively graded electrically insulating device comprising an elongated tubular flexible insulating resin sleeve and including a shaped portion at one end having electrically conducting particles therein to provide measurable conductivity and constituting an electrical stress relief assembly, a series of alternated contacting flat conducting and insulating rings surrounding said sleeve and constituting a multiplicity of series connected condensers, a tubular outer insulator surrounding said rings, a H-V cable having a grounded sheath, insulation within said sheath, and a conductor within said insulation, said cable having an end portion with the sheath removed extending through said sleeve and having its conductor bared beyoNd the end of said sleeve, means electrically connecting said sheath to a conducting ring at one end of said series of rings and means electrically connecting said bared conductor to a conducting ring at the other end of said series, the insulating rings alternated with said conducting rings being formed of plastic having ceramic type filler selected from the group consisting of niobates, silicates, tantalates and zirconates of barium, bismuth, lead and strontium, and oxides of lanthanum and titanium.

Claim 27

A capacitively graded electrically insulating device comprising an elongated tubular flexible insulating resin sleeve and including a shaped portion at one end having electrically conducting particles therein to provide measurable conductivity and constituting an electrical stress relief assembly, a series of alternated contacting flat conducting and insulating rings surrounding said sleeve and constituting a multiplicity of series connected condensers, a tubular outer insulator surrounding said rings, a H-V cable having a grounded sheath, insulation within said sheath, and a conductor within said insulation, said cable having an end portion with the sheath removed extending through said sleeve and having its conductor bared beyoNd the end of said sleeve, means electrically connecting said sheath to a conducting ring at one end of said series of rings and means electrically connecting said bared conductor to a conducting ring at the other end of said series, the insulating rings alternated with said conducting rings being formed of plastic having ceramic type filler selected from the group consisting of niobates, silicates, tantalates and zirconates of barium, bismuth, lead and strontium, and oxides of lanthanum and titanium.

Claim 28

A device as defined in claim 21 in which the plastic of which said rings are formed is selected from the group consisting of epoxy, polyester, silicone, polysulfide, urethane, and combinations thereof; and polyolefin and ABS (Acrylonitrile butadiene styrene).

Claim 29

A capacitively graded electrical insulating device comprising an elongated series of end-contacting flat alternated insulating and conducting elements constituting a series connected group of capacitances, a generally tubular insulating body surrounding said capacitances, said insulating elements being formed of a plastic resin material provided with a ceramic filler selected to produce a high dielectric constant the value of which increases with temperature.

Claim 30

A capacitively graded electrical insulating device comprising an elongated series of end-contacting flat alternated insulating and conducting elements constituting a series connected group of capacitances, a generally tubular insulating body surrounding said capacitances, said insulating elements being formed of a plastic resin material provided with a ceramic filler selected to produce a high dielectric constant the value of which increases with temperature.

Claim 31

A device as defined in claim 23 in which the insulating material of the insulating elements has a non-linear relationship between impressed voltage and resulting current which upon increase in voltage produces a current greater than the current value which would be produced if the current-voltage characteristic was linear.