Abstract: Electrical cable for high and very high voltages includes a plurality of conductors, at least one semiconductive layer, a stratified insulation impregnated with an insulating fluid and an external metal sheath. The insulation is constituted by a paper/polypropylene/paper laminate, wherein polypropylene has been subjected to a treatment such as to allow the laminate to swell up by less than 5% after immersion in decylbenzene at 100.degree. C. for at least 3 days.

Abstract: A DC OF cable has its main insulation composed of a composite insulation tape comprising a low dielectric loss film and kraft paper (PPLP). 1-10 sheets of kraft paper are wound on the PPLP main insulation as a layer on the inside and/or the outside thereof.

Abstract: A method for enhancing the dielectric properties of a new or in-service electrical cable is disclosed, the method comprising supplying the interstitial void space of the cable's conductor with a fluid mixture comprising(A) an antitreeing agent; and(B) a water-reactive compound,wherein (B) has a diffusion coefficient of at least 1.times.10.sup.-7 cm.sup.2 /second at 50.degree. C. in the insulation of the cable and the mixture has an initial viscosity of .ltoreq.100 cP at 25.degree. C. The instant method provides a more symmetrical distribution of dielectric enhancing fluid in the insulation than prior art fluids and results in a significant reduction in cable treatment time.

Abstract: A structure for an electrical cable which may be used as a high-frequency signal transmission line and which includes a jacket which is highly permeable by fluids to reduce the time required for stabilization of impedance and transmission speed of the cable upon placement into an environment characterized by a fluid dielectric having a different dielectric constant. The permeable jacket also facilitates electrical connection to a shield conductor of the transmission line, exposed through apertures in the jacket, by use of electrically conductive potting materials, and without the need to remove any portions of the jacket surrounding the shield conductor to which electrical connection is to be made.

Abstract: A paper-polymeric material, laminated tape, an electric cable insulated with such tape and a method of making the tape. The tape includes a film of polymeric material to at least one surface of which a paper tape comprising cellulose fibers is bonded by contacting the paper tape at room temperature with the film heated to a temperature above its melting temperature. Prior to contacting the paper tape with the heated film, fibrils are caused to project from at least one surface of the paper tape by subjecting it to a high voltage, electrostatic field. In the laminated tape, the fibrils are embedded in the material of the film to provide an improved bond between the film and the paper tape.

Abstract: A method of manufacturing a sensing element, comprising bringing a first body in the form of an oil-free cross-linked matrix of flexible elastomeric material, the matrix containing electrically conductive particles, into contact with a second body of flexible elastomeric material that is electrically insulating and that contains an oil compatible with the elastomeric material of the first body, and allowing oil to migrate from the second to the first body so as to cause swelling of the first body, the migration continuing until a state of oil phase equalisation between the two bodies is reached.

Abstract: The present invention relates to an improved electrical insulating oil composition which has excellent electrical characteristics and is suitable for use in impregnating electrical appliances in which plastic dielectric material is used, and further relates to electrical appliances impregnated with such a composition. The electrical insulating oil composition is produced by bringing a by-product oil fraction mainly containing components having boiling points in the range of 260.degree. to 330.degree. C. (atmospheric pressure basis) into liquid-liquid contact with an organic polar solvent; said by-product oil fraction being formed by alkylating benene or toluene with ethylene in the presence of an alkylation catalyst and then distilling the alkylation product; and said electrical insulating oil composition being characterized in that the ratio of the integrated intensity as chemical shift at 120 to 155 ppm of the spectrum measured by .sup.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: A composite tape for forming at least part of the insulation of a high voltage electrical cable, particularly an oil-filled cable, and a cable including such insulating tape. The composite tape includes at least one layer of paper tape having a borate or silicate weight content in the range form 0.1 to 3% of the weight of the paper bonded to at least one surface or the surfaces of a film of bi-oriented polymeric plastic material by a copolymer layer which has a thickness of from about 1-10 microns. The thickness of all the plastic material in the composite tape is in the range from 10 to 30% of the total thickness of the tape. Preferred polymeric materials are polypropylene and polymethylpentene. A bonding material can be propylene-ethylene copolymer.

Abstract: A high voltage, gas filled, pipe type electrical cable and method of manufacture thereof. The cable comprises a plurality of insulated conductors, each conductor having a central gas passageway and being gas permeable. The conductor is wrapped with tapes impregnated with an insulating oil, and the wrapped tapes are encircled by gas permeable layers and skid wires. Three of such insulated conductors are encircled by a gas impermeable pipe, and the pipe and the conductor passageways are filled with an insulating gas under pressure above atmospheric pressure so that both the interior and exterior surfaces of the wrapped tapes are subjected to such gas. Preferably, the gas is a mixture of sulfur hexafluoride and nitrogen at a pressure of at least 200 psig. The tapes are impregnated with the oil and drained before they are wrapped around the conductor so as to provide gaps between the tapes which are substantially filled with the gas.

Abstract: A high voltage mass impregnated power cable to be used on land and in shallow waters by including in the cable construction a pressure body having a number of pressure tapes applied in several layers on a bedding between the metal sheath and the tapes. The pressure tapes have good elastic properties and may consist of high quality metal or a strong synthetic material and are applied with a short lay length. The pressure body maintains under all load conditions including no-load, an internal pressure on the cable insulation above atmospheric pressure and high enough to prevent creation of voids in the insulation.

Abstract: A direct current electric cable with a conductor, a semi-conductive screen around and contacting the conductor, a plurality of layers of insulation formed by tapes of insulating material around the semi-conductive screen, a further semi-conductive screen around the layers of insulation and a metal sheath around the further semi-conductive screen, the layers of insulation being impregnated with a non-migrating, insulation composition having a dropping point temperature at least 5.degree. C. above the maximum operating temperature of the cable and having an electronegative gas dissolved therein, the gas having a coefficient of diffusion in the composition in the range from 3.times.10.sup.-5 to 3.times.10.sup.-6 cm.sup.2 /sec at temperatures below the dropping point temperature of the composition.

Abstract: An oil-filled electric cable in which the solid insulation is formed, at least in part, by separately applied, alternate layers of cellulose paper tape and of film tapes made of a plastic. Prior to application of the tapes around the cable conductor, the moisture content of the paper tape is selected and the swelling of the plastic tape by the oil after application is adjusted, if necessary, such as by immersing the plastic tape in the oil prior to application, so that the swelling of the plastic tape by the oil in the formed cable is offset by the shrinkage of the paper tape during drying of the cable. Also, apparatus for pre-swelling the plastic tape.

Abstract: An oil-immersion electrically insulated cable of high performance is constructed by wrapping a conductor with insulation formed by winding on the conductor polypropylene film having a density in the range of 0.905 to 0.915 g/cm.sup.3, a birefringence in the range of 0.020 to 0.035, a ratio of strengths in two axial directions (tensile strength in the longitudinal direction/tensile strength in the lateral direction) in the range of 5 to 15, and impregnating the insulating layer with an insulating oil, preferably DDB oil.

Abstract: An improved electrical insulating oil and oil-filled electrical appliances impregnated therewith. The electrical insulating oil can be produced inexpensively but has excellent electrical characteristics and it comprises a fraction having boiling points in the range of 350.degree. to 450.degree. C. that is prepared by disproportionating diarylalkane or a hydrocarbon mixture mainly containing the same at temperatures in the range of 20.degree. to 500.degree. C. in the presence of a disproportionation catalyst, said diarylalkane having boiling points in the range of 260.degree. to 320.degree. C.

Abstract: An oil-filled electric cable in which the solid insulation is formed, at least in part, by separately applied, alternate layers of cellulose paper tape and of film tapes made of a plastic. Prior to application of the tapes around the cable conductor, the moisture content of the paper tape is selected and the swelling of the plastic tape by the oil after application is adjusted, if necessary, such as by immersing the plastic tape in the oil prior to application, so that the swelling of the plastic tape by the oil in the formed cable is offset by the shrinkage of the paper tape during drying of the cable. Also, apparatus for pre-swelling the plastic tape.

Abstract: Method and apparatus for replacing flammable, insulating oil in an oil-filled electric cable by non-flammable, insulating oil in which the flammable oil is withdrawn at least from the cable oil duct under vacuum and with heating of the cable to its maximum operating temperature and thereafter, the flammable oil which was withdrawn is replaced by non-flammable oil. During operation of the cable, oil which flows out of the cable during heating of the cable is sent to a first reservoir, through a check valve and during subsequent cooling, such oil is replaced by non-flammable oil from a second reservoir containing non-flammable oil and connected to the cable duct by a check valve. Also, an oil-filled cable having its insulation impregnated with flammable, insulating oil or a mixture of such oil with non-flammable, insulating oil and having an oil duct filled with a non-flammable, insulating oil which is different from the flammable oil.

Abstract: An electrically insulating laminate paper for an electric apparatus to be wound in a wet state on a conductive material and thereafter impregnated with oil, which is characterized by that water drops having a wide particle size distribution are scattered on the surface of the electrically insulating laminate paper comprising an integrated assembly composed of a plastic film and fiber papers bonded to each other to moisten said fiber papers.

Abstract: An electric power cable insulating fluid which is a substance corresponding to the following formula ##STR1## where R is chosen between the following two radicals: ##STR2## and an electric power cable with its insulation impregnated with such fluid.

Abstract: An oil-filled, multi-core, electric cable having three cores within a metal sheath. Each core has a conductor surrounded by insulation and has substantially the same outer dimensions as the other cores. One conductor is made of copper and has a central oil duct. The other conductors are made of stranded aluminum wires in side-by-side and contacting relation and the ratio of the cross-sectional area of the metal of the copper conductor to the cross-sectional area of the metal of each aluminum conductor is the reciprocal of the ratio of the electrical conductivities thereof.

Abstract: An electric cable having a fluid-tight, metal sheath containing a plurality of cores without oil ducts, each including a conductor surrounded by insulation, and a separate tubular member adjacent and contacting two of the cores and having an oil duct of a cross-sectional area at least equal to the cross-sectional area of the sum of the oil duct cross-sectional areas normally included in each core. The spaces between the tubular member and the cores and between the cores, the tubular member and the sheath are filled with an insulating filler, and the insulation of the cores and the filler are impregnated with an insulating oil and the duct of the tubular member is filled with the insulating oil. The sheath contacts the outer surfaces of the tubular member and the cores, and the oil duct of the tubular member contains a plurality of longitudinally spaced, oil flow restrictors.

Abstract: A high voltage oil-impregnated electrical cable with fully polymer taped insulation operable to 765 kV. Biaxially oriented, specially processed, polyethylene, polybutene or polypropylene tape with an embossed pattern is wound in multiple layers over a conductive core with a permeable screen around the insulation. Conventional oil which closely matches the dielectric constant of the tape is used, and the cable can be impregnated after field installation because of its excellent impregnation characteristics.

Abstract: Disclosed is a method of inhibiting the attack by perchloroethylene on copper and organic polymers subject to said attack, such as parylene, by adding to perchloroethylene about 20 to about 1000 ppm of a stabilizer having the general formula ##STR1## The preferred concentration of the stabilizer is about 40 to about 500 ppm. Also disclosed is an electrical apparatus containing copper or organic polymer subject to attack by perchloroethylene and perchloroethylene containing the stabilizer.

Abstract: A direct current, electric, submarine cable which may be used in long lengths and at great depths and which has improved voltage breakdown characteristics with respect to voids which form in the insulation. The cable has a conductor surrounded by an inner semi-conductive screen which is surrounded by cellulose paper tape insulation which is surrounded by an outer semi-conductive screen which is surrounded by a metal sheath. The paper tape is impregnated with a compound comprising a viscous hydrocarbon oil containing a substance having polar groups, the amount of the substance being sufficient to make the volume resistivity of the compound 100 times lower than the volume resistivity of the tape with the compound therein.

Abstract: The invention concerns an improvement in taped cables having large diameter and suitable for use at voltages up to and over 1000 kV. The taping of one or more layers is wound according to a double-start or multi-start helix, said helix having an inclination less than 75.degree..

Abstract: A method and apparatus for retarding electrochemical tree-type decomposition of polyolefin electrical insulation by saturating the insulation with a liquid having high resistivity and a low dielectric constant. The insulation of cables which have already been in service is dried prior to being saturated with the liquid. One embodiment of the invention provides a continuing supply of liquid to the cable after it has been buried underground.

Abstract: In order to reach every void between the individual cable conductors, particularly when filling a multi-pair communication cable, the water repellent substance is supplied to the cable core in great excess; a filling basin surrounding the filling station proper collects the re-emerging excess substance.

Abstract: Provided is an oil-impregnated power cable comprising an insulation layer formed by winding a composite film of polyolefin film and insulating paper onto an electric conductor and impregnated with an impregnating oil, said impregnating oil comprising distillates within a boiling range in terms of values at normal pressure between 265.degree. C. and 360.degree. C. obtained by contacting a hydrocarbon mixture with a boiling range between 75.degree. C. and 198.degree. C. resulting from a thermal cracking of petroleum hydrocarbons at a temperature of 700.degree. C. or higher and containing monocyclic aromatics and aromatic olefins, in liquid phase with an acid catalyst.

Abstract: The present invention relates to a laminated insulating paper formed of cellulose paper or papers which is adhered to at least one side of cross-linked silicone grafted polyolefine film and to an oil-filled (OF) cable which insulated by the laminated insulating paper. The laminated insulating paper has outstanding peel strength as well as excellent non-solubility and anti-swelling properties in insulating oils.

Abstract: A submarine cable and an electric power line using such cable for transmitting electric power at high voltge from a first point adjacent the surface of a water body to a second point adjacent the surface of a water body, a portion of the cable lying in great water depths where the hydrostatic pressure is high. The cable comprises at least three sections, each section having its insulation dimensioned or selected for operation at the high voltage when subjected to the ambient pressures. The section, or sections, lying at great depths has insulation with a voltage breakdown strength which varies with pressure, the strength increasing with pressure, so that the insulation thereof may be less than would be required if the such sections were to be used under pressures less than those at the great depths.

Abstract: An electric power cable having a Milliken-type conductor comprising at least four sectors, the conductor being paper-insulated and oil filled and each sector comprising metal wires stranded together. Each wire is covered with a layer of a cross-linked synthetic resin having a thermal classification of 120.degree. C., a CEI resistance to abrasion of at least 50 cycles, a CEI thermal pressure value higher than 170.degree. C. and an insulating oil contaminating effect of substantially zero, such resin also being substantially completely volatizable by the heat used for joining cables by welding. Preferred resins are a polyvinyl-acetal resin, such as a polyvinyl-formal resin, cross-linked with a phenol resin and, optionally, a melamine resin and such with the addition of a blocked isocyanate.

Abstract: A transformer having a forced air cooling system is disclosed. The transformer includes an insulating oil which is forcibly moved in the transformer and an insulating sheet which is partially covered with particles, fibers or other forms of an inorganic material for producing a static charge of opposite polarity to the charge produced by the base material of the insulating sheet caused by relative motion due to forced flow of the insulating oil.

Abstract: Electrical apparatus having certain portions thereof insulated with solid insulating structures. The solid insulating structures include a predetermined thickness of polyethylene terephthalate film which is surrounded on each of its major outer surfaces by a layer of paper having a fibrous web formed of wholly aromatic polyamide fibers.

Abstract: A cryogenic power cable of a cryoresistive type having a conductor which is cooled with a cooling medium to permit large capacity power transmission by reducing thereby the electric resistance and the joule loss of the conductor. The temperature of the cable core is controlled through an ingenious arrangement comprising the conductor which incorporates therein a passage for the cooling medium, an electric insulation layer made of an ordinary electric insulating material and a thermal insulating material layer. The cable not only makes ultra-high voltage transmission of 500 to 1000 KV possible but also is advantageous on account of a simple and economic structure.

Abstract: This disclosure deals with the minimization of electric stresses and the increase of breakdown-withstanding capabilities in DC insulation systems or conductivity, or conductance and resistance, within the insulation media. The stress is kept at a minimum by arranging the layers of insulations to follow a particular pattern based on conductivity constants of the material at its distance from the conductor.