Patent Publication Number: US-2015075837-A1

Title: Compression formed connector for carbon-fiber composite core conductor assembly used in transmission line installations and method of constructing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from U.S. Provisional Application No. 61/767,037, filed Feb. 20, 2013, in the United States Patent and Trademark Office, the disclosures of which are incorporated herein in its entirety by reference. 
    
    
     BACKGROUND 
     1. Field 
     The invention is related to a compression formed connector, and more particularly to a compression formed connector for use in transmission line installations. 
     2. Related Art 
     Conventional overhead conductor core material can be held together using conventional power conductor compression accessories without worrying if the conductor core would be damaged. Unfortunately, the newly developed carbon fiber composite core overhead conductor has a core material that is more fragile than the conventional core material and would be damaged by conventional power conductor compression accessories. 
     Therefore, there is a need for a compression accessory to attach the new carbon fiber composite core overhead conductor. There exists two-die compression accessory technology that is currently used to attach conventional overhead conductors. However, no existing two-die compression accessory technology offers a means of attaching compression accessories to the new carbon fiber composite core conductor. The existing two-die compression accessory technology causes damage to the composite core and does not achieve the desired holding strength required to put the accessory into field use. 
     Therefore, there is a need for a compression accessory that will achieve the industry-standard holding strength, while not causing damage to the newly developed carbon fiber composite core of the overhead conductor. 
     SUMMARY 
     Exemplary implementations of the present invention address at least the above problems and/or disadvantages and other disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an exemplary implementation of the present invention may not overcome any of the problems listed above. 
     According to an exemplary embodiment, there is provided a compression accessory, including an insert sleeve configured to enclose at least part of a core strand of a transmission conductor, the insert sleeve having at least one slot on an outer wall of the insert sleeve and a bored sleeve configured to enclose at least part of the insert sleeve, an inner wall of the bored sleeve configured to interact with the at least one slot. 
     In another exemplary embodiment, there is provided a substance that may coat at least part of an inner wall of the insert sleeve, and the substance may aid in gripping the core strand. 
     In one exemplary embodiment, the substance may include a silicon carbide grit. 
     In yet another exemplary embodiment, the bored sleeve may be a bored forging. 
     In one exemplary embodiment, the at least one slot may be formed axially with respect to a through hole of the insert sleeve. 
     According to an exemplary embodiment, the insert sleeve may be configured to be compressed against the core strand. 
     In another exemplary embodiment, the insert sleeve may splice together a plurality of core strands. 
     In one exemplary embodiment, the compression accessory may include a tubular body which may be configured to enclose at least part of an outer strand of the transmission conductor and at least part of the bored sleeve. 
     In yet another exemplary embodiment, the compression accessory may be configured to maintain a holding strength of at least 95%. 
     According to another exemplary embodiment, an outer wall of the bored sleeve may include at least one projection. 
     According to an exemplary embodiment, there is provided a compression accessory, including an insert sleeve having a substance coating at least part of an inner wall of the insert sleeve, where the substance aids in gripping the core strand, and a bored sleeve which is configured to enclose at least part of the insert sleeve. 
     In one exemplary embodiment, an outer wall of the insert sleeve may include at least one slot. 
     According to another exemplary embodiment, the at least one slot may be formed axially with respect to a through hole of the insert sleeve. 
     In yet another exemplary embodiment, the bored sleeve may be a bored forging. 
     According to an exemplary embodiment, the insert sleeve may be configured to be compressed against the core strand. 
     In another exemplary embodiment, the insert sleeve may splice together a plurality of core strands. 
     According to another exemplary embodiment, the compression accessory includes a tubular body which may be configured to enclose at least part of an outer strand of the transmission conductor and at least part of the bored sleeve. 
     In yet another exemplary embodiment, the compression accessory may be configured to maintain a holding strength of at least 95%. 
     According to an exemplary embodiment, there is provided a method of attaching a compression accessory to a transmission conductor, the method including placing an insert sleeve around at least part of a core strand of a transmission conductor, compressing the insert to the core strand, placing a bored sleeve around at least part of the insert sleeve, compressing the bored sleeve to the insert sleeve, wherein at least one slot on an outer wall of the insert sleeve interacts with an inner wall of the bored sleeve, placing a tubular body around at least part of the bored sleeve and at least part of an outer strand of the transmission conductor; and compressing the outer tubular body to the insert sleeve and the outer strand. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features, and advantages of the present invention will become more readily apparent from the following detailed description of exemplary embodiments of the invention, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cutaway view of a deadend compression accessory; 
         FIGS. 2A-2B  are cutaway views of an insert sleeve and a tubular body of a splice compression accessory; 
         FIG. 3A  is a front view of an opening of an insert sleeve of a compression accessory; 
         FIG. 3B  is a side view of an insert sleeve of a compression accessory; 
         FIG. 4  is a side view of a deadend compression accessory attached to a terminal; 
         FIG. 5  is a cutaway view taken along the line  5 - 5  of  FIGS. 1 ,  2 A, and  2 B and illustrates a cross-sectional view of an end portion of either tubular body of a compression accessory compressed around outer strands of a transmission conductor; 
         FIG. 6  is a cutaway view taken along the line  6 - 6  of  FIGS. 1 ,  2 A, and  2 B and illustrates a cross-sectional view of a core load transferring section of a compression accessory; 
         FIG. 7  is a cutaway view taken along the line  7 - 7  of  FIG. 1  and illustrates a cross-sectional view of the tubular body compressed around a bored forging of a deadend compression accessory; 
         FIG. 8  is a cutaway view taken along the line  8 - 8  of  FIG. 1  and illustrates a cross-sectional view of the tubular body compressed around a corrugation of the bored forging of a deadend compression accessory; 
         FIG. 9  is a cutaway view taken along the line  9 - 9  of  FIG. 1  and illustrates a cross-sectional view of the uncompressed tubular body enclosing the bored forging of a deadend compression accessory; and 
         FIG. 10  is a cutaway view taken along the line  10 - 10  of  FIGS. 1 ,  2 A, and  2 B and illustrates the manner in which the bored forging and insert sleeve of the compression accessory are compressed onto the core strand of a transmission conductor. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is provided to gain a comprehensive understanding of the methods, apparatuses and/or systems described herein. Various changes, modifications, and equivalents of the systems, apparatuses and/or methods described herein will suggest themselves to those of ordinary skill in the art. Descriptions of well-known functions and structures are omitted to enhance clarity and conciseness. 
     In the following description, like drawing reference numerals are used for like elements, even in different drawings. The matters defined in the description, such as detailed construction and elements, are provided to assist in a comprehensive understanding of exemplary embodiments. However, exemplary embodiments can be practiced without those specifically defined matters, and the inventive concept may be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Also, well-known functions or constructions are not described in detail when it is deemed they would obscure the application with unnecessary detail. 
     It will be understood that, although the terms used in the present specification may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. 
     Hereinafter, the term “splice compression accessory” refers to a device for joining two or more transmission conductors. This term may be used interchangeably with the term “joint compression accessory” or any other term known in the art that is used to join two or more elements such as, but not limited to, transmission conductors. 
     Hereinafter, an exemplary embodiment will be described with reference to the accompanying drawings. 
     Referring to the drawings,  FIG. 4  shows an exemplary embodiment of a deadend compression accessory  10   a , while  FIG. 2  shows an exemplary embodiment of a splice compression accessory  10   b . The deadend compression accessory  10   a  and the splice compression accessory  10   b  are two exemplary embodiments of a compression accessory  10 . Any reference made herein to the compression accessory  10  includes, but is not limited to, the deadend compression accessory  10   a  and the splice compression accessory  10   b.    
     Referring to the drawings,  FIG. 4  shows an exemplary embodiment of the deadend compression accessory  10   a  connected to a terminal  40  via a terminal pad  42 , according to an exemplary embodiment. 
     As shown in  FIG. 1 , there is a cutaway view of the deadend compression accessory  10   a  according to an exemplary embodiment. In this exemplary embodiment, the deadend compression accessory  10   a  includes a bored forging  16 , an insert sleeve  14 , and a tubular body  12 . The insert sleeve  14  has a first end  15   a  and a second end  15   b , as shown in  FIG. 2A . In one exemplary embodiment, the insert sleeve  14  is a hollow sleeve having a polygonal (hexagonal, circular, etc.) cross-sectional shape. In one exemplary embodiment, it is preferred that the insert sleeve  14  be constructed from a suitable conductive material, such as aluminum. However, it will be understood that the insert sleeve  14  can be constructed from any material having the necessary rates of ductility and extrusion to connect carbon fiber composite core overhead conductors. Furthermore, it will be understood that the insert sleeve can be any shape, depending on the characteristics of the strand  24 , the shape of a compression die (not shown), or the desired use of the compression accessory  10 . 
     The insert sleeve  14  has an interior wall  14   a , as illustrated in  FIG. 3A . In one exemplary embodiment, the insert sleeve  14  has a diameter slightly greater than the diameter of a core strand  24  of a transmission conductor  20 . Thus, the insert sleeve  14  can fit snugly around the core strand  24 . 
     It will be understood that the diameter of the interior wall  14   a  is not limited, and may vary depending on the characteristics of the core strand  24 , the shape of a compression die (not shown), or the desired use of the compression accessory  10 . In addition, the insert sleeve  14  includes one or more slots  30  on an outer wall  14   b , as shown in  FIGS. 3A and 3B . According to one exemplary embodiment, the inner wall  14   a  is lined with a silicon carbide grit (not shown) to prevent the insert sleeve  14  from sliding along core strand  24  and to prevent the core strand  24  from snapping. It will be understood that a silicon carbide grit is but one exemplary embodiment of the invention, and any substance known in the art, which is suitable to increase the gripping strength of the insert sleeve  14  according to the necessary specifications, may be used to coat the inner wall  14   a.    
     The slots  30  on the outer wall  14   b  and the silicon carbide grit that lines an inner wall  14   a  of insert sleeve  14  provides additional holding strength to grip a transmission conductor  20 . This assists the deadend compression accessory  10   a  or the splice compression accessory  10   b  to maintain a proper holding strength of the conductor system without compromising the integrity of a conductor system, while allowing the transmission conductor  20  to carry the electrical current through either compression accessory  10 . The conductor system includes, but is not limited to, the transmission conductor  20  and the compression accessory  10 . 
     In one exemplary embodiment, the compression accessory  10  assists in providing a conductor system rated holding strength of at least 95%. However, it will be understood that the compression accessory  10  can assist in maintaining different holding strengths depending on the characteristics of the conductor system and the desired use of the compression accessory  10 . 
     In one exemplary embodiment, insert sleeve  14  includes five slots  30  on the outer wall  14   b . However, it will be understood that insert sleeve  14  can be constructed with any number of slots  30  in order to provide the proper holding strength, according to the characteristics of the strand  24  or the conductor system, the shape of a compression die (not shown), or the desired use of the compression accessory  10 . Furthermore, in one exemplary embodiment, the slots  30  are configured axially with respect to a center of a through hole (not shown) of the insert sleeve  14 , the through hole having the inner wall  14   a .  14 . However, the slots  30  may be configured in any direction, including being transverse with respect to a center of the through hole of the insert sleeve  14 . 
     Referring to  FIG. 1 , according to an exemplary embodiment, there exists a steel-formed bored forging  16 . The bored forging  16  includes corrugations  18  and an eye-hole  16   a  at a first end of the bored forging  16 . In an exemplary embodiment, the bored forging  16  has a polygonal (hexagonal, circular, etc.) cross sectional shape. However, it will be understood that the bored forging  16  can be any shape, determined by the shape of the insert sleeve  14  or the tubular body  12 , or determined by the desired use of the compression accessory  10 . In addition, the bored forging  16  has an inner diameter slightly larger than the outer diameter of the insert sleeve  14 . Thus, the bored forging  16  can fit snugly around the insert sleeve  14 . It will be understood that the inner diameter of the bored forging  16  is not limited, and may vary depending on the characteristics of the insert sleeve  14 , the shape of a compression die (not shown), or the desired use of the compression accessory  10 . 
     While the bored forging  16  is constructed from a suitable steel material, it will be understood that the bored forging  16  can be constructed from any material having the necessary rates of ductility and extrusion to connect carbon fiber composite core overhead conductors. Furthermore, the eye-hole  16   a  is but one shape and size of the first end of the bored forging  16 . It will be understood that the eye-hole  16   a  can be any size or shape depending on the characteristics of the connector system. 
     An aluminum tubular body  12  is provided, having a first end  13   a  and a second end  13   b . In an exemplary embodiment, the tubular body  12  has a polygonal (hexagonal, circular, etc.) cross sectional shape, as illustrated by  FIGS. 2A and 2B . However, it will be understood that tubular body  12  can be any shape, depending on the characteristics of the strand  24 , the shape of a compression die (not shown), or the desired use of the compression accessory  10 . 
     In one exemplary embodiment, the tubular body  12  has an inner diameter slightly larger than the outer diameter of an outer strand  22  of the transmission conductor  20 , so the tubular body  12  can fit snugly around the outer strand  22 . It will be understood that the inner diameter of the tubular body is not limited, and may vary depending on the characteristics of the transmission conductor  20 , bored forging  16 , the bored sleeve  50 , the shape of a compression die (not shown), or the desired use of the compression accessory  10 . 
     Although tubular body  12  is constructed from a suitable aluminum material in one preferred embodiment, it will again be understood that the tubular body  12  can be constructed from any material having the necessary rates of ductility and extrusion to connect carbon fiber composite core overhead conductors and to allow the transmission conductor  20  to carry the electrical current through the compression accessory  10 . 
     In one exemplary embodiment, the transmission conductor  20  is provided, having a core strand  24  and an outer strand  22 . The core strand  24  and the outer strand  22  are each constructed with at least one or more strands, which are suitable to conduct high current transfer (power) across long distances. 
     In a preferred embodiment, the outer strand  22  is constructed to include twenty-six ( 26 ) strands constructed of aluminum. However, it will be understood that the outer strand  22  may be constructed from any number of strands, the strands being constructed using any material suitable to conduct high current transfer (power). 
     In addition, in an exemplary embodiment, the core strand  24  of the transmission conductor  20  is provided with seven (7) strands, each strand being constructed of a carbon fiber polymer mix. However, it will be further understood that core strand  22  may be constructed from any number of strands, and the strands may be constructed using any material suitable to conduct high current transfer (power). 
     Referring now to  FIGS. 2A and 2B , there exists another preferred embodiment of the compression accessory  10 , including the splice compression accessory  10   b . The splice compression accessory  10   b  includes the insert sleeve  14 , with inner wall  14   a  covered in a grit-like substance and the outer wall  14   b  having slots  30 . In addition, the splice compression accessory  10   b  includes a bored sleeve  50  to cover the insert sleeve  14 , and the tubular body  12  to cover the bored sleeve  50  and the outer strand  22  of the transmission conductor. The bored sleeve  50  includes a first end  50   a  and a second end  50   b , as shown in  FIGS. 2A and 2B . Furthermore, while it is preferred that the bored sleeve  50  is composed of steel, it will be understood that bored sleeve  50  may be composed of any material known in the art having the necessary rates of ductility and extrusion to connect carbon fiber composite core overhead conductors. 
     The interaction of the above-identified features will now be explained, according to one or more exemplary embodiments. 
     As shown in  FIG. 2A , in both the deadend compression accessory  10   a  and the splice compression accessory  10   b , the insert sleeve  14  is placed around the core strand  24  so that the diameter of the inner wall  14   a  of the insert sleeve  14  encloses at least part of the core strand  24 . The inner wall  14   a  is covered with the grit, increasing the holding strength of the compression accessory  10  on the transmission conductor  20 . The grit, along with the slots  30  on outer wall  14   b , assist in maintaining the required holding strength for the conductor system. As seen in  FIGS. 2A and 2B , the insert sleeve  14  does not extend along the entire length of the core strand  24 . However, if necessary, the insert sleeve can extend along the entire length of the core strand  24 . 
     According to an exemplary embodiment, the bored forging  16  of the deadend compression accessory  10   a  is placed around the insert sleeve  14 . The bored forging  16  encloses at least part of the insert sleeve  14 . As shown in  FIG. 1 , the bored forging  16  does not extend along the entire length of the insert sleeve  14 . However, depending on the specification and requirements of the holding strength of the compression accessory  10 , the bored forging may extend along the entire length of the insert sleeve  14 . 
     The tubular body  12  is positioned so as to enclose at least part of the outer strand  22  and the bored forging  16 , according to an exemplary embodiment of the deadend compression accessory  10   a , as illustrated in  FIG. 1 . In one exemplary embodiment, the tubular body  12  is able to interact with the corrugations  18  on the bored forging  16  in order to increase a gripping strength of the compression accessory  10   a  on the transmission conductor  20 . It will be understood that corrugations  18  may include any type of projection or projections, such as, but not limited to, a screw thread. 
     In another exemplary embodiment, the bored sleeve  50  includes corrugations  30  on an outer wall. As with the bored forging  16 , the corrugations  30  are not limited thereto, and the bored sleeve  50  may include any type of projection of projections. 
     According to an exemplary embodiment, the deadend compression accessory  10   b  is attached to a terminal  40  by the bored forging  16 , the terminal pad  42 , and the tubular body  12  as shown in  FIG. 4 . The bored forging  16  has a washer  44  toward the end of the bored forging  16  having eye hole  16   a . The bored forging  16  is placed into the tubular body  12  so that at least part of the bored forging  16  is enclosed by tubular body  12 . The deadend compression accessory  10   a  is attached to the terminal  40  by the tubular body  12 , which is welded to the terminal pad  42  at B, as shown in  FIG. 4 . It will be understood that the deadend compression accessory  10   a  can be attached to the terminal  40  by any method known in the art. 
     The eye hole  16   a  of bored forging  16  is positioned on a first side of the terminal pad  42 , the washer  44  being placed between the eye hole  16   a  and the terminal pad  42 . The tubular body  12  is then placed so as to enclose as least part of bored forging  16 , as discussed in further detail above. In one exemplary embodiment, the washer  44  is constructed of felt. However, the washer may be constructed of any material known in the art to insulate the terminal  40  and terminal pad  42  from the compression accessory  10 . 
     In another exemplary embodiment, the sleeve  14  in the splice compression accessory  10   b  is positioned so as to enclose at least part of two or more core strands  24 , as shown in  FIG. 2B . This allows the splice compression accessory  10   b  to splice, or join together, the two or more core strands  24 . As shown in  FIG. 2B , the two or more core strands  24  will be spliced together and an end of each of the two or more core strands  24  will abut each other at A. In addition, the bored sleeve  50  of the splice compression accessory  10   b  encloses at least part of the insert sleeve  14 , as shown in  FIG. 2B . As with the bored forging  16 , the bored sleeve  50  may or may not extend along the entire length of the insert sleeve  14 . 
     As seen in  FIGS. 5-10 , there is shown cross-sectional views of exemplary embodiments of a compression accessory  10 . While each of  FIGS. 5-10  show cross-sectional views of exemplary embodiments of the deadend compression accessory  10   a , it will be understood that these cross-sectional views are illustrative of exemplary embodiment of the splice compression accessory  10   b.    
     Referring now to  FIG. 5 , there is shown a cross-sectional view of the tubular body  12  of a compression accessory  10  enclosing and compressing the outer strand  22  of a transmission conductor  20 . In addition, the core strand  24  can be seen being enclosed by the outer strand  22 . While the compressed tubular body  12  is shown as a hexagon, it will be understood that the compression may form any other polygonal or circular shape. 
     As seen in  FIG. 6 , there is illustrated a cross-sectional view of an uncompressed tubular body  12 ′ enclosing a bored forging  16  of the deadend compression accessory  10   a . The bored forging  16  is enclosing and compressed around the insert sleeve  14 , which in turn encloses and is compressed to the core strand  24  of the transmission conductor  20 . It will be understood that the bored forging  16  is illustrative of a compression of the bored sleeve  50  of the splice compression accessory  10   b  around the insert sleeve  14 . 
       FIG. 7  shows a cross-sectional view of the tubular body  12  compressed to the bored forging  16 . It will be understood that bored forging  16  of  FIG. 7  is illustrative of a compression of the tubular body  12  to the bored sleeve  50  of the splice compression accessory  10   b . In addition,  FIG. 8  shows a cross-sectional view of the tubular body  12  compressed to the corrugation  18  of the bored forging  16 . 
     As illustrated in  FIGS. 9 and 10 , there is shown a cross-sectional view of the uncompressed tubular body  12 ′ enclosing the bored forging  16 , where the bored forging is enclosing and compressed to the insert sleeve  14 , which in turn is enclosing and compressed to the core strand  24 . It will be understood that the bored forging  16  of  FIGS. 9 and 10  is illustrative of the bored sleeve  50  of the splice compression accessory  10   b.    
     Next, a method of assembling the above-identified features will be provided, according to an exemplary embodiment. 
     In one exemplary embodiment, a steel hexagonal die (not shown) is used to compress the steel bored forging  16  or, alternatively, the bored sleeve  50 , and the aluminum insert sleeve  14  onto core strand  24 . However, the die is not limited to a steel hexagonal die, and may be constructed of any material and be any shape known to one of ordinary skill in the art, depending on the material and shape of the bored forging  16 , the bored sleeve  50 , or the insert sleeve  14 . 
     During the compression of the bored forging  16  and the insert sleeve  14  or the compression of the bored sleeve  50  and the insert sleeve  14 , the insert sleeve  14  is compressed so that the slots  30  are compressed against the inner wall (not shown) of the bored forging  16  or an inner wall (not shown) of the bored sleeve  50 , and the grit on the inner wall  14   a  of the insert sleeve  14  is compressed against the core strand  24 . The combination of the slots  30  and the grit assist in providing a suitable holding strength over the conductor system and allows the transmission conductor  20  to carry the electrical current through the compression accessory  10 . 
     According to another exemplary embodiment, after the bored forging  16  and the insert sleeve  14  are compressed around the core strand  24 , the tubular body  12  is placed over bored forging  16 , so as to enclose at least part of bored forging  16 , and the transmission conductor  20 , so as to enclose at least part of outer strand  22 . An aluminum hexagonal die (not shown) is used to compress the tubular body  12  over the outer strand  22 . The placement of tubular body  12  is such that tubular body  12  is compressed over at least part of the outer strand  22  and at least part of the bored forging  16 . 
     During the compression of the tubular body  12 , the tubular body  12  and the corrugations  18  are compressed, increasing the holding strength between the tubular body  12  and the bored forging  16 . In addition, the tubular body  12  is compressed around the outer strand  22 , further assisting in providing the proper holding strength between the compression accessory  10  and the transmission conductor  20 , to provide the required holding strength over the entire conductor system. 
     In yet another exemplary embodiment, the tubular body  12  encloses at least part of the bored sleeve  50  and the outer strand  22  of the transmission conductor  20 , as shown in  FIG. 2B . An aluminum hexagonal die (not shown) is used to compress the tubular body  12  over the outer strand  22 . The placement of tubular body  12  is such that tubular body  12  is compressed over at least part of the outer strand  22  and at least part of the bored sleeve  50 . This compression assists the compression accessory to maintain the required holding strength of the conductor system. 
     It will be understood that the die is not limited to an aluminum hexagonal die, and may be constructed of any material and be any shape known to one of ordinary skill in the art, depending on the material and shape of the bored forging  16 , the bored sleeve  50 , or the outer strand  22 . 
     It will also be understood that the compression of both the bored forging  16  or the bored sleeve  50  around the insert sleeve  14  and the core strand  24 , and the compression of the tubular body  12  around the bored forging  16  around the bored sleeve  50  and the outer strand  22  may be accomplished using any other method known in the art, and is not limited to compression dies. 
     As discussed above, although the exemplary embodiments described above is a compression accessory for a core conductor, they are merely exemplary and the general inventive concept should not be limited thereto, and it could also apply to other types of compression accessories and other types of cables. Furthermore, while exemplary embodiments described above indicated shapes and/or materials of a compression accessory for a core conductor, any shape and/or materials of the compression or the core conductor known to one skilled in the art may be used, depending on the user&#39;s preference as well as the requirements of the specific situation.