Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
  • H02G5/00—Installations of bus-bars
  • H02G5/06—Totally-enclosed installations, e.g. in metal casings
  • H02G5/063—Totally-enclosed installations, e.g. in metal casings filled with oil or gas
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B9/00—Power cables
  • H01B9/06—Gas-pressure cables; Oil-pressure cables; Cables for use in conduits under fluid pressure
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S505/00—Superconductor technology: apparatus, material, process
  • Y10S505/825—Apparatus per se, device per se, or process of making or operating same
  • Y10S505/884—Conductor
  • Y10S505/885—Cooling, or feeding, circulating, or distributing fluid; in superconductive apparatus

Definitions

• the present invention concerns a gas-filled cable intended for the transmission of high-voltage electric current and consisting of one or more conductors, these being held axially in position in the cable by means of supporting insul ⁇ ators inside an enclosing conduit filled with an insulating gaseous medium.
• gas-filled cables may be used for both underground and surface, transmission of elect ⁇ ric current up to about 1 ,000 kV.
• gas-filled surface cables By comparison with overhead power-lines carrying the same voltage, gas-filled surface cables have proved to have a greater current-carrying capacity and at the same time to be less liable to operational disturbances.
• a major disadvantage of such cables has, until now, been the high cost of manufacture, the chief contributor to this being the outer conduit of the cable itself which must be so constructed as to keep pow-er losses at a reasonable level . Laboratory tests have previously indicated that carbon steel is an unsuitable material for cable conduits, one reason for this being that its use is associated with large losses of power .
• a method known previously in connection with cooling systems for superconducting cryogenic cables uses a cable cond comprising an outer sheath of high-alloy steel consisting of a iron/nickel alloy containing 30-45% nickel, and an inner linin or shield of e.g. aluminium.
• a cable cond comprising an outer sheath of high-alloy steel consisting of a iron/nickel alloy containing 30-45% nickel, and an inner linin or shield of e.g. aluminium.
• the main objective of the invention is to reduce hea emission from gas-filled cables at the same time as power loss are kept low and the total manufacturing costs are such that t cable type will be able to compete on the market.
• the conduit comprises a cylindric metal sheath of magnetic material enclosing a metal shield of non-magnetic material having low resistivity.
• the shield may also b cylindrical; a suitable thickness for this has been found to b approx. 8-30% of the total thickness of the conduit, although 12-20% is to be preferred.
• Another objective of the invention is to achieve a cable of the type ..under discussion in which the insulation be ⁇ tween the conduit and the conductors running inside the cable is maintained at a constant high level of efficiency throughou the life of the cable, for it has been found that in gas-fille cables of the conventional type small particles, of e.g. metal often remain inside the cable after it has been brought into service. These particles may be concentrated to certain pLaces
• Figure 1 shows a perspective view of a section through a gas-filled cable for three-phase alternating current construct ⁇ ed as per the invention.
• Figure 2 shows a side view of the cable illustrated in Fig. 1 , part of the cable being shown cut away.
• Figure 3 shows a modified version of the cable illustr ⁇ ated in Figure 1 in which, for the sake of clarity, the conductors and insulators have been omitted.
• the gas-filled cable illustrated in Figures 1 and 2 comprises an outer conduit 10, 12 in which three conductors 14 are held in position by means of supporting insulators 16.
• the space 18 between the conductors 14 and the conduit 10, 12 is filled with an insulating gaseous medium, sulphur hexaf1 uori de , SFg, being a suitable gas, kept at a ⁇ pressure of approximately three atmospheres.
• sulphur hexaf1 uori de SFg
• SFg a suitable gas
• the conduit of the. cable comprises an outer sheath 10 fitting snugly round a meta lining or shield 12.
• a suitable material for the outer sheath is plain carbon steel , while aluminium may be used to advantag for the shield 12.
• the shield 12 which, like the enclosing sheath 10, is cylindrical , fits snugly insi the sheath.
• the shield 12 may be of sheet metal and may be form as it is drawn into the sheath so that it becomes a tight-fitti lining to the sheath itself. After forming, the edges of the shield may be united by welding inside the enclosing sheath.
• the shield 12 may also consist of a separate pipe introduced directly into the enclosing sheath 10, in which cas the shield 12 may be pressed tightly against the sheath by e.g expansion.
• the outer sheath 10 is formed of 10 mm thick sheet steel , the carb content of which is about 0.2%.
• the diameter of the conduit is 800 mm.
• the shield 12 is of aluminium plate, 2 mm thick, and the complete conduit encloses the three conductors 14, these also being of aluminium and consisting of pipes having a dia ⁇ meter of 100 mm and walls 5 mm thick. How the conductors are to be arranged in relation to one another is shown in principl in Figure 1, although it should be noted that their exact posi tion will be dependent on the voltage later to be carried by the cable.
• the three conductors 14 are held in position by con ⁇ ventional supporting insulators 16 located inside the gas-fill cable at a suitable distance from each other along each indivi dual conductor.
• the insulators consist of separate elements, the ends of which are securely fastened to the cable conduit 10, 12 and the conductor 14 in question by e.g. screws. In ord to facilitate assembly of these insulators 16 in the cable, it is also possible to unite them with the conductors so that- separate units are formed which may be individually introduced into the conduit 10, 12.
• an outer sheath 10 and a shield 12' of essent ⁇ ially the same type as the version shown in Figures 1 and 2 are used.
• the shield 12' has been modified so as to leave a space 20 between the shield 12' and the sheath 10 along part of the inside surface of the sheath 10. This is achieved by grooving the shield 12' in an axial direction before it is inserted into the sheath 10. The grooved part of the shield should face downwards while the cable is being used.
• the space 20 between the shield 12' and its enclosing sheath 10 mentioned above will then face downwards and should provide a clearance of one or a few mm between the two.
• the shield 12' is pierced by a number ⁇ of slot-shaped holes 22 spaced at intervals along the length of the cable which form a passage between the space 20 and the interior of the cable itself 18. Any particle remaining inside the cable after assembly will be set in motion by the electro ⁇ static field generated by use of the cable, but under the in ⁇ fluence of gravity will gradually be made to "fall” through the slots 22 and remain trapped in the space 20 between the two parts of the conduit, that is between the outer sheath 10 and the shield

Landscapes

• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Insulated Conductors (AREA)
• Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
• Installation Of Bus-Bars (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20333945

Family Applications (1)

Country Status (8)

Cited By (3)

Families Citing this family (11)

Citations (5)

Family Cites Families (3)

• 1978
  • 1978-02-09 SE SE7801543A patent/SE7801543L/xx unknown
• 1979
  • 1979-02-08 CA CA321,119A patent/CA1123070A/en not_active Expired
  • 1979-02-08 GB GB8006660A patent/GB2037061A/en not_active Withdrawn
  • 1979-02-08 US US06/185,919 patent/US4347401A/en not_active Expired - Lifetime
  • 1979-02-08 WO PCT/SE1979/000025 patent/WO1979000607A1/en not_active Ceased
  • 1979-02-08 JP JP50038079A patent/JPS55500201A/ja active Pending
  • 1979-02-09 AU AU44125/79A patent/AU4412579A/en not_active Abandoned
  • 1979-08-28 EP EP79900179A patent/EP0009495A1/en not_active Withdrawn

Patent Citations (5)

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