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EP-3758178-B1 - COVER ASSEMBLIES AND METHODS FOR COVERING ELECTRICAL CABLES AND CONNECTIONS

EP3758178B1EP 3758178 B1EP3758178 B1EP 3758178B1EP-3758178-B1

Inventors

  • YAWORSKI, HARRY
  • TSE, ALAN
  • YANG, LIZHANG

Dates

Publication Date
20260506
Application Date
20160909

Claims (8)

  1. A pre-expanded cover assembly (401) configured to protect a cable splice connection (15) including cables (40, 50) and a connector (60), the cables (40, 50) including electrical conductors (42, 52) surrounded by cable insulation layers (44, 54), the pre-expanded cover assembly (401) comprising: a splice body assembly (420) including: a tubular, cold-shrinkable, electrically insulative, elastomeric splice body (430) having an interior surface (430 A) defining an interior passage; a tubular layer (454) of a conformable high permittivity medium that is a flowable high electrical permittivity mastic having a dielectric constant in the range of from 15 to 25 pre-mounted on the interior surface of the splice body; and a tubular layer (470, 472) of a conformable insulating medium pre-mounted on the interior surface of the splice body (430), wherein the conformable insulating medium is a flowable electrically insulating mastic having a dielectric constant in the range of from about 2 to 8; and a removable holdout (102), wherein the splice body assembly (420) is mounted on the holdout (102) such that the holdout (102) maintains the splice body (430) in an elastically radially expanded state, and the holdout (102) is selectively removable from the splice body (430) to permit the splice body (430) to elastically radially contract; the splice body (430) includes a tubular primary insulation layer (432) formed of an electrically insulating elastomer, the primary insulation layer extending from a first axial end (432A) to an opposed second axial end (432B); the interior passage terminates at the first and second axial ends (432A, 432B); the layer (470) of the conformable electrically insulating mastic consists of a first layer comprising a distal end (470A) and a proximal end (470B) and a second layer comprising a proximal end (472A) and a distal end (472B); the proximal end (470B) of the first insulating mastic layer (470) is spaced apart from the proximal end (472A) of the second insulating mastic layer (472); the distal end (470A) of the first insulating mastic layer (470) is spaced from the first axial end (432A) of the primary insulation layer (432) and the distal end (472B) of the second insulating mastic layer (472) is spaced from the second axial end (432B) of the primary insulating layer (432); the layer (454) of the conformable high permittivity medium comprises a first layer of the high permittivity mastic (454) extending from the first axial end (432A) of the primary insulation layer (432) to the first layer (470A) of the electrically insulating mastic (470) and a second layer of the high permittivity mastic(454) extending from the second axial end (432B) of the primary insulation layer (432) to the second layer (472B) of the electrically insulating mastic; the splice body assembly (420) further includes a third layer (452) of the high permittivity mastic extending from adjacent the proximal end (470B) of the first electrically insulating mastic layer (470) to the proximal end (472A) of the second electrically insulating mastic layer; and the inner surfaces of the high permittivity mastic layers (454, 452) and of the insulating mastic layers (470, 472) collectively define a mastic passage (477) extending from the first axial end (432A) of the primary insulation layer (432) to the second axial end (432B) of the primary insulation layer (432); wherein the layer (454) of the conformable high permittivity medium is positioned and configured such that, when the pre-expanded cover assembly (401) is positioned adjacent the cable splice connection (15), the holdout (102) is removed from the splice body (430), and the splice body (430) elastically radially contracts onto the cable splice connection (15), the layer (454) of the conformable high permittivity medium will be radially interposed between and engage each of the interior surface (430A) of the splice body (430) and opposing interface surfaces of the cable insulation layers (44, 54); and wherein the layer (470, 472) of the conformable insulating medium is positioned and configured such that, when the pre-expanded cover assembly (401) is positioned adjacent the cable splice connection (430), the holdout (102) is removed from the splice body (430), and the splice body (430) elastically radially contracts onto the cable splice connection (15), the layer (470, 472) of the conformable insulating medium will be radially interposed between and engage each of the interior surface (430A) of the splice body and opposing interface surfaces of the cable insulation layers (44, 54).
  2. The pre-expanded cover assembly (401) of Claim 1 wherein the layer (454) of the conformable high permittivity medium is positioned and configured such that, when the pre-expanded cover assembly (401) is positioned adjacent the cable splice connection (15), the holdout (102) is removed from the splice body (430), and the splice body (430) elastically radially contracts onto the cable splice connection (15), the layer (454) of the conformable high permittivity medium will further engage cable semiconductor layers (45, 55) of the cables (40, 50) and will surround a terminal edge (45A, 55A) of each of the cable semiconductor layers (45, 55).
  3. The pre-expanded cover assembly (401) of Claim 1 wherein the splice body (430) includes a tubular primary insulation layer (432) formed of extruded silicone or ethylene propylene diene monomer (EPDM) rubber.
  4. The pre-expanded cover assembly (401) of Claim 3 wherein the splice body (430) further includes a semiconductor layer (438) covering an outer surface of the primary insulation layer (432).
  5. The pre-expanded cover assembly of Claim 1 wherein the holdout (102) includes a tubular holdout formed by a helically wound strip, and the holdout is configured to be removed from the splice body assembly (420) by pulling the strip.
  6. A method of manufacturing a pre-expanded cover assembly (401) according to claim 1, the method comprising: mounting a tubular layer (454) of a conformable high permittivity medium on a removable holdout (102), wherein the conformable high permittivity medium is a flowable material having a high electrical permittivity; mounting a tubular layer (470, 472) of a conformable insulating medium on the removable holdout (102), wherein the conformable insulating medium is a flowable material that is electrically insulating; and thereafter mounting a tubular, cold-shrinkable, electrically insulative, elastomeric splice body (430) on the holdout (102) over the conformable medium such that the holdout (102) maintains the splice body (430) in an elastically radially expanded state and an interior surface of the splice body (430) defines an interior passage and engages the layer (454) of the conformable high permittivity medium and the layer (470, 472) of the conformable insulating medium; wherein the holdout (102) is selectively removable from the splice body (430) to permit the splice body to elastically radially contract; the layer (454) of the conformable high permittivity medium is positioned and configured such that, when the pre-expanded cover assembly (401) is positioned adjacent the cable splice connection (15), the holdout (102) is removed from the splice body (430), and the splice body (430) elastically radially contracts onto the cable splice connection (15), the layer (454) of the conformable high permittivity medium will be radially interposed between and engage each of the interior surface of the splice body (430) and opposing interface surfaces of the cable insulation layers; and the layer (470, 472) of the conformable insulating medium is positioned and configured such that, when the pre-expanded cover assembly (401) is positioned adjacent the cable splice connection (15), the holdout (102) is removed from the splice body (430), and the splice body (430) elastically radially contracts onto the cable splice connection (15), the layer (470, 472) of the conformable insulating medium will be radially interposed between and engage each of the interior surface (430A) of the splice body and opposing interface surfaces of the cable insulation layers (44, 54).
  7. A method for protecting a cable splice connection (15) including cables (40, 50), the cables including electrical conductors (42, 52) surrounded by a cable insulation layer (44, 54), the method comprising: providing a pre-expanded cover assembly (401) according to claim 1; and mounting the splice body assembly (420) on the splice connection, including: positioning the pre-expanded splice body assembly (401) adjacent the cable splice connection (15); and removing the holdout (102) from the splice body assembly (420) to permit the splice body (430) to elastically radially contract onto the cable splice connection (15) such that: the layer (454) of the conformable high permittivity medium (430A) is radially interposed between and engages each of the interior surface of the splice body and opposing interface surfaces of the cable insulation layers (44, 54); and the layer (470, 472) of the conformable insulating medium is radially interposed between and engages each of the interior surface (430A) of the splice body and opposing interface surfaces of the cable insulation layers (44, 54).
  8. The method of Claim 7 wherein, when the holdout (102) is removed from the splice body (430), and the splice body (430) elastically radially contracts onto the cable splice connection (15), the layer (454) of the conformable high permittivity medium engages cable semiconductor layers (45, 55) of the cables and surrounds a terminal edge (45A, 55A) of each of the cable semiconductor layers (45, 55).

Description

Field of the Invention The present invention relates to electrical cables and connections and, more particularly, to pre-expanded cover assemblies configured as protective covers for electrical cables and electrical connections. Background of the Invention In the electrical utilities industry, maintaining cable integrity may be critical. A loss of cable integrity, for example, a short circuit in a high voltage cable, may result in a crippling power outage or, even worse, a loss of life. One everyday task that may pose a great threat to cable integrity is the formation of electrical connections. When electrical connections are formed, a bare metal surface may be exposed such as a splice connector. These bare metal surfaces may be particularly hazardous when formed in the field where they are exposed to the environment. This environment may include rocks and other sharp objects as well as moisture when the connection is to be buried under ground and rainfall when the connection is to be suspended in the air. Thus, there is a need to protect such electrical connections from the environment. The use of pre-fabricated cover assemblies for protecting cable splice connections is known and is described by Cheenne-Astorino et al in DOI: 10.1109/TDC.1996.545964 and also in US 2014/0262500 and EP 1 206 024 in which an elastomeric splice body is mounted on a plastic support tube or hold-out. The splice body-hold out assembly is placed over the cable splice connection and the hold-out is removed to allow the elastomeric splice body to contract onto the splice connection. The elastomeric splice body may include high dielectric constant mastic layers on its inner surface. Summary of the Invention According to embodiments of the invention, a pre-expanded cover assembly for protecting a cable splice connection including a cable, the cable including an electrical conductor surrounded by a cable insulation layer, includes a splice body assembly and a removable holdout as defined in claim 1. The splice body assembly includes a tubular, cold-shrinkable, electrically insulative, elastomeric splice body having an interior surface defining an interior passage. The splice body assembly further includes a tubular layer of a conformable medium pre-mounted on the interior surface of the splice body. The conformable medium is a flowable material having a high electrical permittivity. The splice body further comprises a tubular layer of a conformable insulating medium pre-mounted on the interior surface of the splice body, wherein the conformable insulating medium is a flowable material that is electrically insulating. The splice body assembly is mounted on the holdout such that the holdout maintains the splice body in an elastically radially expanded state, and the holdout is selectively removable from the splice body to permit the splice body to elastically radially contract. The layer of the conformable medium is positioned and configured such that, when the pre-expanded cover assembly is positioned adjacent the cable splice connection, the holdout is removed from the splice body, and the splice body elastically radially contracts onto the cable splice connection, the layer of the conformable medium will be radially interposed between and engage each of the interior surface of the splice body and an opposing interface surface of the cable insulation. According to method embodiments of the invention, a method of manufacturing a pre-expanded cover assembly for protecting a cable splice connection including a cable, the cable including an electrical conductor surrounded by a cable insulation layer, as defined in claim 6, includes: mounting a tubular layer of a conformable medium on a removable holdout, wherein the conformable medium is a flowable material having a high electrical permittivity; mounting a tubular layer of a conformable insulating medium on the removable holdout, wherein the conformable insulating medium is a flowable material that is electrically insulating ;and thereafter mounting a tubular, cold-shrinkable, electrically insulative, elastomeric splice body on the holdout over the conformable medium such that the holdout maintains the splice body in an elastically radially expanded state and an interior surface of the splice body defines an interior passage and engages the conformable medium. The holdout is selectively removable from the splice body to permit the splice body to elastically radially contract. The layers of the conformable media are positioned and configured such that, when the pre-expanded cover assembly is positioned adjacent the cable splice connection, the holdout is removed from the splice body, and the splice body elastically radially contracts onto the cable splice connection, the layers of the conformable media will be radially interposed between and engage each of the interior surface of the splice body and an opposing interface surface of the cable insulation. According to method embodiments of t