Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
  • H01B1/023—Alloys based on aluminium
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B9/00—Power cables
  • H01B9/006—Constructional features relating to the conductors

Definitions

• This invention relates to electrical power cable. More particularly, this invention relates to electrical power cable having enhanced electrical conductivity, better compaction of electrical conductor material within the space available in the cable for electrical conductor material, and reduced distribution losses.
• Suggested methods for reducing resistive power losses of power conductors/cables include use of conductors made of high electrical conductivity materials (say, copper, silver, aluminum, etc). However, in power conductors/cables, considering economic viability, aluminum/aluminum alloys are most widely used conductor material.
• bare overhead conductors are prone to variations in performance due to dynamic climatic conditions. They also suffer from problems of ageing, sagging and easy thefts of electricity. Also, bare overhead conductors need a grid infrastructural setup, which at times, is not easy to provide everywhere.
• electrical power cables offer some advantages such as: electrical power cables are better immune to power thefts and they can be easily laid underground (or even hanged overhead in some cases) at locations where provision of overhead bare power conductor/s may not be safe or easy. Also, use of electrical power cables releases expensive urban land for better use. Electric power cable circuit is more reliable and has much better up-time. It also allows better landscaping.
• An object of this invention is to provide a technically improved electrical power cable which comprises of compactly packed non-circular cross-section high electrical conductivity aluminum strands which are prepared from special processing and treatment of aluminum.
• the aluminum strands of the electric power cable have enhanced electrical conductivity which is at least 60% IACS (International Annealed Copper Standard).
• the technically improved electrical power cable of the present invention would have enhanced electrical conductivity, better compaction of electric conductor material within the space available in the cable for electrical conductor material, and reduced distribution losses. Better compaction of electric conductor material is helpful in efficient filling of the space available in the cable with electrical conductor material. As a result of better compaction, more electric conductor material can be filled within the available space and overall electrical conductivity of the cable is increased further.
• Another object of this invention is to provide a technically improved electrical power cable which comprises of compactly packed trapezoidal cross-section high electrical conductivity aluminum strands which are prepared from special processing and treatment of aluminum.
• the aluminum strands of the electric power cable have enhanced electrical conductivity (> 60% IACS).
• the technically improved electrical power cable of the present invention 1 would have enhanced electrical conductivity, better compaction of electric conductor material within the space available in the cable for electrical conductor material, and reduced distribution losses. Better compaction of electric conductor material is helpful in efficient filling of the space available in the cable with electrical conductor material. As a result of better compaction, more electric conductor material can be filled within the available space and overall electrical conductivity of the cable is increased further.
• Still another object of this invention is to provide a technically improved medium volt (MV i.e., 6.6 KV-33KV) electrical power cable which comprises of compactly packed trapezoidal cross-section high electrical conductivity aluminum strands which are prepared from special processing and treatment of aluminum.
• the aluminum strands of the electric power cable have enhanced electrical conductivity (> 60% IACS).
• the technically improved medium volt electrical power cable of the present invention would have enhanced electrical conductivity, better compaction of electrical conductor material within the space available in the cable for electrical conductor material and reduced distribution losses (such as reduced DC resistance, reduced I 2 R losses and better immunity to theft of electric power).
• the electrical power cable of the present invention includes a conductor component, said conductor component is a defined path through which electric current would flow in the cable.
• the conductor component further includes compactly packed trapezoidal cross-section aluminum strands which are prepared from special processing and treatment of aluminum.
• an aluminum rod is prepared from high electrical conductivity aluminum; said high electrical conductivity aluminum is obtained by treating molten aluminum with boron for removal of conductivity decreasing impurities (say, impurities of transition metals such as titanium, vanadium, chromium, zirconium, etc.).
• impurities say, impurities of transition metals such as titanium, vanadium, chromium, zirconium, etc.
• trapezoidal cross-section strands are obtained from the aluminum rod.
• obtained trapezoidal cross-section strands are annealed under controlled conditions for a predetermined duration. During the annealing process, the obtained trapezoidal cross-section strands are firstly heated to a temperature of 320 °C in an annealing furnace for duration of 15-18 hours.
• the trapezoidal cross-section strands (and circular cross-section aluminum strands, if any) are arranged in a manner such that cross-section of each of the trapezoidal cross-section strands does not lie in tangential contact with the cross-section of any other strand which lies adjacent to it and belongs to the conductor component (in other words, the trapezoidal cross- section strands are arranged in a manner such that cross-section of each of the trapezoidal cross-section strand lies in contact with cross-section of every other strand which lies adjacent to it and belongs to the conductor component at more than one points).
• trapezoidal cross-section strands and circular cross-section aluminum strands, if any are compactly packed in a manner such that, Due to use of trapezoidal cross-section strands, inter-strand voids are reduced and more electrical conductor material (i.e. high electrical conductivity aluminum having enhanced electrical conductivity which is > 60% IACS) is packed within the space' available in the cable for electrical conductor material. Better compaction of electric conductor material is helpful in efficient filling of the space available in the cable with electrical conductor material and improving the overall electrical conductivity of the cable is increased further.
• electrical conductor material i.e. high electrical conductivity aluminum having enhanced electrical conductivity which is > 60% IACS
• Figure 1 shows a perspective view of an electrical power cable in accordance with the first embodiment of the present invention.
• Figure 2 shows a cross-sectional view of the electrical power cable in accordance with the first embodiment of the present invention.
• Figure 3 shows a perspective view of an electrical power cable in accordance with the second embodiment of the present invention.
• Figure 4 shows a cross-sectional view of the electrical power cable in accordance with the second embodiment of the present invention.
• This invention relates to a technically improved electrical power cable which includes compactly packed non-circular cross-section aluminum strands which are prepared from special processing and treatment of aluminum.
• the aluminum strands of the electric power cable have enhanced electrical conductivity (> 60% IACS).
• the technically improved electrical power cable of the present invention has enhanced electrical conductivity, better compaction of electrical conductor material within the space available in the cable for electrical conductor material and reduced distribution losses (such as reduced DC resistance, reduced 1 2 R losses and better immunity to theft of electric power).
• the non-circular cross- section aluminum strands are arranged within the electrical power cable in a manner such that, the cross-section of each of non-circular cross-section aluminum strands does not lie in tangential contact with the cross-section of any other aluminum strand which lies adjacent to it (in other words, each of the non-circular cross-section aluminum strands are arranged in a manner such that the cross-section of each of the non-circular cross-section aluminum strand lies in contact with cross-section of every other aluminum strand which lies adjacent to it at more than one points). Due to such an arrangement of non-circular cross-section aluminum strands, inter-strand voids are reduced, more electrical conductor material is packed within the space available in the cable for electrical conductor material, and a compact packing of strands is achieved.
• the electrical power cable provided by this invention includes a conductor component, said conductor component is a defined path through which electric current would flow in the cable.
• the conductor component further includes a central conductor surrounded by two layers of compactly packed trapezoidal cross-section strands.
• the central conductor is a circular cross-section strand.
• the central conductor and trapezoidal cross-section strands in layers surrounding it are prepared from specially processed and treated aluminum.
• the central conductor and Trapezoidal cross-section strands in layers surrounding it have enhanced electrical conductivity (> 60% IACS).
• an aluminum rod is prepared from high electrical conductivity aluminum; said high electrical conductivity aluminum is obtained by treating molten aluminum with boron for removal of conductivity decreasing impurities (say, impurities of transition metals such as titanium, vanadium, chromium, zirconium, etc.). Thereafter, an aluminum rod/s is prepared from boron treated aluminum.
• aluminum strands which would form the central conductor and the trapezoidal cross-section strands in layers surrounding it are obtained from said aluminum rods by drawing them through specifically designed dies (different dies are used to draw strands which would from central conductor and trapezoidal cross-section strands of layers surrounding the central conductor).
• obtained strands are annealed under controlled conditions for a predetermined duration.
• the obtained aluminum strands are heated to a temperature of 320 °C in an annealing furnace for duration of 15-18 hours. Thereafter, heated strands are gradually allowed to cool for about 12-15 hours till they reach the room temperature. Annealing the strands in the described manner further improves their electrical conductivity. After annealing, the strands are ready to be used for manufacturing the electric power cable of present invention.
• the trapezoidal cross-section aluminum strands thus obtained are packed in a very compact manner around the central conductor to provide more electrical conductor material per unit volume of the space available for the conductor component within the electrical power cable.
• the trapezoidal cross-section strands are arranged in a manner such that cross- section of each of the trapezoidal cross-section strands does not lie in tangential contact with the cross-section of any other strand which lies adjacent to it and belongs to the conductor component (in other words, the trapezoidal cross-section strands are arranged in a manner such that cross-section of each of the trapezoidal cross-section strand lies in contact with cross-section of every other strand which lies adjacent to it and belongs to the conductor component at more than one points).
• Figure 1 is a perspective view of the electrical power cable in accordance with the first embodiment of the present invention
• Figure 2 shows a cross-sectional view of the electrical power cable in accordance with the first embodiment of the present invention (i.e. Figure 2 is a cross-sectional view of the electrical power cable shown in Figure 1).
• the electrical power cable 100 comprises of a longitudinal axis AA'and a conductor component 102 which lies symmetrically around the longitudinal axis AA'.
• the conductor component 102 is the path through which electric current would flow in the cable.
• the conductor component 102 includes a central conductor 104.
• the central conductor 104 is a circular cross-section strand.
• the central conductor 104 is surrounded by an inner layer 106.
• Inner layer 106 is formed of multiple compactly packed trapezoidal cross-section strands 108.
• inner layer 106 is formed by helically winding and compactly packing multiple trapezoidal cross-section strands 108 around the central conductor 104 and the axis AA' as shown in figure 1 and figure 2.
• Strands 108 are symmetrically laid around the central conductor 104 as shown in figure 1 and figure 2.
• Inner layer 106 is further surrounded by an outer layer 110.
• Outer layer 110 is formed by helically winding multiple trapezoidal cross-section strands 112 around inner layer 106 and the axis AA' in a manner as shown in figure 1 and figure 2.
• Strands 112 are symmetrically laid around inner layer 106 as shown in figure 1 and figure 2.
• Both inner layer 106 and outer layer 110 are compactly laid around central conductor 104 and longitudinal axis AA' in a manner such that there is substantially little or no voids left in between the adjacent strands.
• the central conductor 104, inner layer 106 (along with strands 108) and the outer layer 110 (along with strands 112) together form the conductor component 102 of the electrical power cable 100.
• central conductor 104 and the trapezoidal cross- section strands 108 and 112 are made of high electrical conductivity aluminum (> 60% IACS). Central conductor 104 and the trapezoidal cross-section strands 108 and 112 are prepared from special processing and treatment of aluminum.
• obtained strands are annealed under controlled conditions for a predetermined duration.
• the obtained aluminum strands are heated to a temperature of 320 °C in an annealing furnace for duration of 15-18 hours. Thereafter, heated strands are gradually allowed to cool for about 12-15 hours till they reach the room temperature.
• Annealing the strands in the described manner further improves their electrical conductivity.
• the above mentioned process and treatment provided high electrical conductivity aluminum strands (upto 64.9 % IACS).
• the strands are ready to be used for manufacturing the electric power cable of present invention.
• the above mentioned process and treatment provided high electrical conductivity aluminum strands (upto 64.9 % IACS).
• central conductor 104 and the trapezoidal cross-section strands 108 and 112 of layers 106 and 110 respectively are packed in a very compact manner to provide more electrical conductor material per unit volume of the space available within the electrical power cable 100 for conductor component 102.
• the trapezoidal cross-section strands 108 and 112 are arranged in a manner such that cross-section of each of the trapezoidal cross-section strands 108 and 112 does not lie in tangential contact with the cross-section of any other strand which lies adjacent to it and belongs to the conductor component 102 (in other words, the trapezoidal cross-section strands 108 and 112 are arranged in a manner such that cross-section of each of the trapezoidal cross-section strands 108 and 112 lies in contact with cross-section of every strand which adjacent to it and belongs to the conductor component 102 at more than one points).
• the conductor component 102 is further surrounded by multiple layers of coverings for providing features such as cable insulation, safety, strength and armoring.
• the outer layer 110 (or the conductor component 102) is surrounded by a covering of extruded semiconducting screen i.e. covering 114.
• Covering 114 is further surrounded by a covering of extruded XLPE insulation i.e. covering 116.
• Covering 116 is further covered by an extruded semiconducting insulation sheath i.e. covering 118.
• Covering 118 is still further surrounded by a helical covering of aluminum round wire armor (or flat wire armor) i.e. Covering 120.
• covering 120 is covered by a covering of extruded PVC/polyethylene i.e. cover 122.
• scope of the present invention is not limited by the embodiment described above.
• the scope of the invention is also not limited by the physical dimensions of the embodiment of electrical power cable (and its components) described above.
• scope of the present invention is not limited by dimensions and shape of central conductor 104, and the dimensions of trapezoidal cross-section strands 108 and 112.
• the scope of the invention is also not limited by the material type, composition, thickness, order of arrangement and diametrical dimensions of coverings 114, 116, 118, 120, and 122.
• the electric power cable includes atleast one conductor component of for carrying electricity (i.e to offer path/s within the cable for electric current to travel), and said atleast one conductor component further including atleast two non-circular corss-section aluminum strands.
• scope of the invention is not limited by the corss-sectional shape of said atleast two non-circular corss-section aluminum strands.
• embodiments of the invention which include triangular corss-section aluminum strands within its conductor component/s are also fully covered within the scope of the invention.
• FIG. 3 is a perspective view of the electrical power cable in accordance with the second embodiment of the present invention
• figure 4 shows a cross-sectional view of the electrical power cable in accordance with the second embodiment of the present invention (i.e. figure 4 is a cross-sectional view of the electrical power cable shown in figure 3).
• the electrical power cable 200 comprises of a longitudinal axis BB' and three cores 202a, 202b and 202c. All three cores 202a, 202b and 202c are laid symmetrically around the longitudinal axis BB'. All three cores 202a, 202b and 202c are similar in structure, material composition and electrical properties. .
• core 202a comprises of a central conductor 204.
• the central conductor 204 has a circular cross section and is surrounded by an inner layer 206.
• Inner layer 206 is formed of multiple compactly packed trapezoidal cross-section strands 208.
• inner layer 206 is formed by helically winding and compactly packing multiple trapezoidal cross-section strands 208 around the central conductor 204 as shown in figure 3 and figure 4.
• Strands 208 are symmetrically laid around the central conductor 204 as shown in figure 3 and figure 4.
• Inner layer 206 is further surrounded by an outer layer 210.
• Outer layer 210 is formed by helically winding and compactly packing multiple trapezoidal cross-section strands 212 around inner layer 206.
• Strands 212 are symmetrically laid around the Inner layer 206 in a manner as shown in figure 3 and figure 4.
• the outer layer 210 is surrounded by a covering of extruded semiconducting screen i.e. covering 214.
• Covering 214 is further surrounded by a covering of extruded XLPE insulation i.e. covering 216.
• Covering 216 is further covered by a semiconducting insulation sheath i.e. covering 218.
• Covering 218 is still further surrounded by helically applied copper tape sheath i.e. Covering 220.
• the central conductor 204 and trapezoidal cross-section strands 208 and 212 of layers 206 and 210 respectively are made of high electrical conductivity aluminum (> 60% IACS).
• Central conductor 204 and trapezoidal cross-section strands 208 and 212 are prepared by the same process as described above in the first embodiment of the invention.
• Cores 202b and 202c are similar to core 202a in structure, material composition and electrical properties. Since all cores 202a, 202b and 202c are same in structure, material composition and electrical properties, for simplicity of explanation, only core 202a is explained in detail.
• the central conductor 204, inner layer 206, outer layer 210 together form the conductor component of core 202a.
• both inner layer 206 and outer layer 210 are compactly laid around central conductor 204 in a manner such that there is substantially little or no voids left in between the adjacent strands.
• the central conductor and trapezoidal strands are packed in a very compact manner to provide more electrical conductor material (i.e. high electrical conductivity aluminum) within the space available for conductor component.
• central conductor 204 and the trapezoidal cross-section strands 208 and 212 are packed in a very compact manner to provide more electrical conductor material (i.e. high electrical conductivity aluminum) within the space available for conductor component.
• the trapezoidal cross-section aluminum strands of both inner and outer layers are arranged in a manner such that cross-section of each trapezoidal cross-section strand does not lie in tangential contact with the cross-section of any other strand which lies adjacent to it and belongs to the same core (in other words, the trapezoidal cross-section aluminum strands of both inner and outer layers are arranged in a manner such that cross-section of each trapezoidal cross-section aluminum strand lies in contact with cross-section of every strand which lies adjacent to it and belongs to the same core at more than one points).
• the trapezoidal cross-section aluminum strands 208 and 212 are arranged in a manner such that cross-section of each trapezoidal cross-section aluminum strands 208 and 212 does not lie in tangential contact with the cross-section of any other strand which lies adjacent to it and belongs to the same core (in other words, the trapezoidal Cross-section aluminum strands 208 and 212 are arranged in a manner such that cross-section of each trapezoidal cross-section aluminum strand 208 and 212 lies in contact with every strand which lies adjacent to it and belongs to the same core at more than one points).
• trapezoidal cross-section strands 208 and 212 Due to such an arrangement of trapezoidal cross-section strands 208 and 212, inter-strand voids are reduced, more electrical conductor material is packed within the space available in the electric power cable 200 for electrical conductor material, and a compact packing of strands is achieved. Similar arrangement of trapezoidal cross-section strands in cores 202b and 202c resulted in enhancing overall electrical conductivity of the electrical power cable 200.
• all three cores 202a, 202b and 202c are surrounded by multiple layers of coverings for providing features such as cable insulation, safety, strength and armoring.
• all three cores 202a, 202b and 202c are packed together within a sheath 222 which is made from extruded (polyvinyl chloride) PVC.
• Inter core space left between the three cores and lying within sheath 222 is filled with PVC fillers 224.
• Sheath 222 is further covered with a covering of galvanized Iron (GI) steel flat strip (or round wire) armoring for safety and strength i.e. covering 226.
• covering 226 is further covered with an extruded PVC/polyethylene outer sheath i.e. covering 228.
• the dimensions and shape of central conductor (say, 204 for core 202a), the dimensions of trapezoidal cross-section strands 208 and 212, and the type, composition and dimensions of coverings of the cores ( layers 214, 216, 218 and 220 for core 202a, and similar corresponding coverings of cores 202b and 202c), and coverings 222, 226, and 228, and PVC filler 224, are optimized to get enhanced electrical conductivity from the cable.
• these parameters be considered to limit the scope of the invention.
• central conductors say, 204
• the dimensions of trapezoidal cross-section strands surrounding central conductors say, 208 and 212 for central conductors 204
• the type, composition and dimensions of coverings of the cores say, 214, 216, 218 and 220 for core 202a, corresponding coverings of cores 202b and 202c
• coverings 2222, 226, and 228, and composition of filler 224 are very well covered within the scope of the invention.
• embodiments of the invention may include cable types having two or more than three conductor components.
• the provision of insulation and other coverings may be provided suitably on case to case basis.
• the scope of invention and its embodiments is not limited by the number of conductor components, cross-sectional shape (and dimensions) of non-circular cross-section strands of the conductor components, and the material type, order of arrangement and dimensions of coverings.
• embodiments of the invention which include triangular cross-section aluminum strands within its conductor component/s are also fully covered within the scope of the invention.
• the scope of invention and its embodiments is not limited by the dimensions of electric power cable, dimensions of conductor component/s, and thickness dimensions of coverings.

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• Crystallography & Structural Chemistry (AREA)
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• 2012
  • 2012-11-29 WO PCT/IN2012/000777 patent/WO2013102925A2/fr not_active Ceased

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