CABLE TERMINATION FOR HIGH- VOLT AGE CABLE APPLICATION

BACKGROUND

[0001] The present invention relates to cable terminations for high-voltage applications. Cable terminations are available for indoor and outdoor applications. Cable terminations are manufactured of various, generally non-conductive materials, such as porcelain, polymer based materials, or both. The material used for manufacturing as well as the dimensions of the cable termination depend at least in part on desired characteristics of the cable termination and the voltage rating of the cable supported by the cable termination.

SUMMARY

[0002] In one embodiment, the invention provides a cable termination including a tubular body having an outer surface and a through aperture, and at least one shed extending from the outer surface. The shed includes an outer edge and a first support coupled to the shed. The first support extends between the outer surface of the tubular body and the outer edge of the shed, and is configured to increase the rigidity of the shed.

[0003] In another embodiment, the invention provides a cable termination including a tubular body with an outer surface and a through aperture, a first shed extending from the outer surface, and a second shed extending from the outer surface. The cable termination also includes a first support coupled to the first shed and extending from the outer surface, and a second support coupled to the second shed and extending from the outer surface. The first support is off-set from the second support by an angle between about 0 and 180 degrees with respect to a central axis extending through the tubular body.

[0004] In another embodiment, the invention provides a cable termination including a tubular body with a first end, a second end, and an outer surface. The cable termination also includes a first shed and a second shed integrally formed with the tubular body and extending from the outer surface, a first support integrally formed with the tubular body and the first shed, and a second support integrally formed with the tubular body and the second shed. The tubular body is formed with a non-conductive rubber material and defines a creepage distance between the first end and the second end along the outer surface of the tubular body and the first shed and the second shed.

[0005] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Fig. 1 is a cable termination according to one embodiment of the present invention.

[0007] Fig. 2 is a top view of the cable termination.

[0008] Fig. 3 is a cross-sectional view along line A-A in Fig. 2.

[0009] Fig. 4 is a detailed view of the cable termination illustrated in Fig. 1.

DETAILED DESCRIPTION

[0010] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

[0011] Figs. 1 through 4 illustrate an exemplary cable termination 10 operable to support a high- voltage cable 11 therethrough and to connect the high- voltage cable 11 to ground 14 (schematically shown in Fig. 3). In the illustrated construction, the cable termination 10 is defined by a substantially elongated tubular body 12 extending along a center axis 65 (Fig. 3). The cable termination 10 includes a first end 17, and second end 22 and a through aperture 19 extending between the first end 17 and the second end 22. The cable termination 10 also includes a first portion 15 adjacent to the first end 17. The first end 17 has a first diameter. The cable termination also has a second portion 20 adjacent to the second end 22. The second end 22 has a second diameter. In the illustrated construction, the second diameter is greater than the first diameter. However, other constructions of the cable termination 10 can include a tubular body with a constant diameter or alternatively more than two portions with different diameters. The cable termination 10 also includes a number of sheds 35 extending from the tubular body 12, which are described in more detail below.

[0012] As indicated above, the cable termination 10 is operable to support a high- voltage cable 11 extending therethrough, where the second end 22 of the cable termination 10 is adjacent to the ground 14. Accordingly, the first end 17 of the cable termination 10 can be defined as the high-voltage end and a second end 22 can be defined as the ground or connecting end of the cable termination 10. Moreover, the longitudinal distance on the surface of the cable termination 10 and between the first end 17 and the second end 22 can be defined as the creepage distance. For the purposes of this application, "creepage" is defined as the electrical leakage on a solid dialectric surface (e.g., the surface of the cable termination 10). Accordingly, the "creepage distance" is the shortest distance on the dielectric surface between two conductive elements (e.g., high- voltage cable 11 and the ground 14), where current tracks or crawls across a generally non-conductive element between two conductive elements.

[0013] The dimensions of the cable termination 10 are at least in part based on the voltage rating of the cable extending through the cable termination 10 (e.g., cable 11 in Fig. 3). For example, the longitudinal distance between the first end 17 and the second end 22 can be calculated or determined based on the voltage rating of the cable supported by the cable termination 10. In one embodiment of the invention, the cable termination 10 is designed to support a cable with a voltage rating generally between 69 kV and 800 kV. For a voltage rating of 130 kV, the longitudinal distance between the first end 17 and the second end 22 of the cable termination is about 8 ft.

[0014] In the embodiments shown in Figs. 1 and 4, a number of sheds 35 extend radially from an outer surface 40 of the tubular body 12. In the illustrated construction, the longitudinal distance between any two sheds 35 is substantially constant. Each shed 35 is defined by a substantially flat plate in a ring-like form including a top surface 45 and a bottom surface 46. The top and bottom surfaces 45, 46 of each shed 35 are defined between an inner edge 50 and an outer edge 55 of the ring- like plate. The diameter of the inner edge 50 is dependent on the portion of the cable termination 10 from which the shed 35 extends. For example, a shed 35 extending from the second portion 20 includes an inner edge 50 with a larger diameter than a shed 35 extending from the first portion 15. However, the radial distance between the inner edge 50 and the outer edge 55 is substantially equal for every shed 35 of the cable termination 10. In the illustrated construction, the inner edge 50 and the outer

edge 55 define an annulus. However, the inner edge 50 and outer edge 55 can define different shapes in other constructions of the cable termination 10.

[0015] With reference to Fig. 4, the cable termination 10 also includes a set of four supports 60 integrally molded with each shed 35 (only three supports 60 for each shed 35 are shown in Fig. 4). Each support 60 includes a rib extending from the outer surface 40 of the cable termination 10 to the outer edge 55 of the shed 35. The four supports 60 corresponding to a shed 35 are separated from one another by a 90 degree angle. Additionally, the ribs of supports 60 coupled to one shed 35 (for example, supports 60A) are offset with respect to the ribs of supports 60 coupled to an immediately adjacent shed 35 (for example, supports 60B) by a 45 degree angle. The ribs of each support 60 are substantially perpendicular to a center axis 65 (shown in Fig. 3) of the cable termination 10. Other constructions of the cable termination 10 can include a different number of supports 60 coupled to each shed 35 as well as a different angular separation between each support 60. For example, two supports 60 can be separated by an angle between about 45 and about 180 degrees. The supports 60 can also include a shape different than the one illustrated in Fig. 4. Also, supports 60 of one shed 35 can be off-set with supports 60 of another shed 35 by an angle between about 0 and about 180 degrees.

[0016] With reference to Fig. 3, the through aperture 19 of the cable termination 10 includes a first part 70 aligned with the axis 65 and includes a first diameter d. The through aperture 19 also includes a second part 75 that is also aligned with the axis 65 and includes a second diameter D. In the illustrated construction, the diameter D of the second part 75 is greater than diameter d of the first part 70. When the cable termination 10 and the high- voltage cable 11 are assembled, the cable 11 snugly fits through the first part 70 of the through aperture 19. A space 77 is formed between the outer surface of the cable 11 and the inner surface of the second part 75 of the through aperture 19. In some constructions, the space 77 at least partially surrounds a connection or support element (not shown) of the high- voltage cable 11.

[0017] Still with reference to Fig. 3, the illustrated construction of the cable termination 10 includes a primary or main portion 80 and a secondary or inner portion 85 integrally formed with the primary portion 80 and adjacent to the second end 22 of the cable termination 10. The main portion 80 of the cable termination 10 is manufactured of a silicon rubber material and includes the sheds 35. The inner portion 85 of the cable termination 10

includes a molded rubber electrode. The molded rubber electrode of the inner portion 85 can be a silicon-based material with semiconductive properties. Other constructions of the cable termination 10 can include one or more portions of silicon rubber material with additives that provide the one or more portions with conductive properties based on desired parameters of the cable termination 10.

[0018] One advantage of manufacturing the cable termination 10 of a silicon rubber material is that the silicon rubber material provides the cable termination 10 with a self- cleaning feature. More specifically, the cable termination 10 can deform in a manner such that dirt, debris and other undesired elements are cleaned from the sheds 35 by natural agents (e.g., wind and rain). In addition, forming the sheds 35 with the silicon rubber material and providing the sheds 35 with the supports 60 allows the sheds 35 to deform such that the self- cleaning can occur but contact of the sheds 35 with one another is prevented or reduced.

[0019] Another advantage of manufacturing the cable termination 10 with silicon rubber material and forming supports 60 is that the supports 60 allow the use of less material in the manufacturing of the cable termination 10 which reduces costs. As a consequence, the cable termination 10 can include a relatively low number of sheds 35 and the sheds 35 can include a thinner annulus. The use of less silicon rubber material and the cable termination 10 including a lesser number of sheds 35 results in the cable termination 10 providing a longer creepage distance, thus improving the performance of the cable termination 10.

[0020] Various features and advantages of the invention are set forth in the following claims.