Waterproof High Voltage Connection Apparatus

Abstract

A high-voltage connector construction capable of use in submersible or exposed areas. The metallic connector itself and its connection to the conductor of a shielded cable are surrounded by a semi-conductive body of elastomeric material which engages the cable metallic connector and acts to prevent voltage differential and resulting corona within air gaps in and around the connection. A two-piece insulating housing of elastomeric material surrounds the semi-conductive body. The housing has a conductive or semi-conductive outer coating sprayed or dipped onto its outer surface, the outer surface being engaged in a sealing relation with a moisture seal, the moisture seal being fabricated of conductive or semi-conductive elastomeric material and being capable of sealing the entrance of the cable to the insulating housing and conductively engaging the cable shield.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

It is well-known in the art that in high voltage connectors for use on shielded cables, that protection must be built-in to prevent corona while maintaining the shielding usually at ground potential. To provide this protection in a waterproof sealable housing is the aim of the present invention.

2. Description of the Prior Art

The prior art shows many devices for solving the problems noted above. In some of these, metallic outer casings are used to provide the necessary shielding. The sealing of these requires glands and other cumbersome sealing arrangements such as manually taping the joint. In the use of resilient or elastic housings, some proposed solutions have required the molding of conductive or semi-conductive elastomeric material over the entire outer surface such as in a composite housing, which may be relatively expensive. In addition, the prior art has shown members requiring taping to produce waterproof seals, requiring expensive labor during the installation of said devices in the field, and requiring extra assembly time.

SUMMARY OF THE INVENTION

The invention provides an inexpensive apparatus which is capable of use with a number of different cable diameters and provides corona protection within a housing which can be readily sealed to cables having different diameters, without requiring expensive outer molded housings of conductive or semi-conductive elastomeric material, nor requiring manual taping.

The corona protection is provided by surrounding the connection to the cable conductor with an assembled, two-piece body of elastomeric material which engages the cable shield at one end and forms a stress relief cone, and at the other end surrounds the metallic connector to which the cable conductor is attached with conductive or semi-conductive material to produce a zero voltage gradient at high voltages. The entire body assembly has a spray or dip conductive coating on its outer surface. The insulating housing is fabricated of elastomeric material which fits tightly over the exposed insulation of the cable. The outermost end of the housing has an inset wall leading to a tapered end section adjoining the cable, thus forming the stress relief cone. The inset wall section is peripherally ribbed with a series of annular ribs, the ribs mating with complementary ribs on the inner wall of an electrically conductive or semi-conductive moisture sealing member, the member at its other end sealingly engaging the cable conductive shield both physically and electrically to complete the moisture seal and the conductive shielding path.

It is therefore an object of the invention to provide a new and improved high voltage connection protected against corona and readily sealable against moisture.

It is a further object of the invention to provide a high voltage connector structure using the inherent elastic character of elastomer materials, insulating and sealing members to effect the protection needed.

It is still a further object of the invention to provide an improved cable termination readily sealed against moisture and dissipative of high voltages.

It is a major object of the invention to provide at the cable entrance of the connector a molded semi-conductive section to produce a moisture seal cooperative with the cable and to provide electrical connection between cable semi-conductive shielding and the dipped or sprayed shielding on main housing without the necessity of manual operations such as taping of the connection in the field.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a loadbreak terminator type connector employing my invention;

FIG. 2 is a sectional view of the connector of FIG. 1.

In FIGS. 1 and 2, I show my invention applied to a loadbreak terminator type connector structure 10. Such terminators as are well-known in the art are used in high voltage applications to provide a safe separable connection between the conductor of a shielded cable and such members as transformer bushings and the like.

The connector structure comprises an exterior one-piece housing 12, generally L-shaped or elbowed, annular in cross section with a central tubular cavity 14. At the lower end as viewed in FIG. 1, the structure receives a shielded cable 16 at one end for connection within the housing to an electrode 18, as will be described. Suitable ground wire 19 is connected to the housing and to cable 16 in any convenient fashion.

The housing contains a hook-shaped lifting eye 20 in alignment with respect to electrode 18 at the opposite end of the structure therefrom. The lifting eye 20 contains a finger opening allowing the eye to be grasped by a suitable implement for the purpose of detaching the electrode from the apparatus bushing, or the like, thereby breaking the circuit between the cable and said apparatus.

The housing 12 further contains a capacitive test point 30 of any known design with graspable cover 32 having a lifting hook eye therein. The test point has been shown herein to aid in describing a typical structure using my invention.

The shielded cable 16 as is conventional has a conductive outer grounding shield 34, an inner insulating sheath 36 and the innermost wire conductor 38. To form a connection in the usual manner, the sheath and shield are respectively removed to expose the sheath and an end section of the wire conductor 38. A metallic compression connector 42 is affixed to the wire conductor to provide a current path to the connector. The connector 42 also has secured thereto the electrode 18.

In the exemplary form shown in FIGS. 1 and 2, the electrode 18 extends within a bushing cavity 14 at right angles to the cable and may be secured to the connector by the use of mating threaded members for example, externally threading the electrode in area 44 for engagement with suitable tapped opening 46 in the connector so that engagement can be made against the electrode shoulder 50.

Physically surrounding the connector is a molded semi-conductive shield 60 of suitable elastomeric material. This shield is generally tubular in shape to receive the connector and its inner tubular wall 62 makes contact with said connector 42 and with the end of the exposed cable insulation so that any entrapped air will be surrounded by an equal potential, and at the other end 64 the shield engages the apparatus bushing (not shown) which fits within the bushing cavity 14 about the electrode 18.

The main housing 12 comprises a molded member of insulating elastomeric material circumposed about the semi-conductive shield 60, this insulating member physically engaging the cable insulation along a portion of its length to provide a proper creepage path to prevent electrical failure under high voltage stress. The housing 12 includes at its bushing end 65 a folded back portion 66 which is an insulator to produce an outer insulating surface 67. In this way the outer semi-conductive coating on the housing establishes shielding all the way to the bottom of the bushing opening but with the outside portion of surface 67 insulating, there will be no flash over from electrode to coating.

At what is shown as the lower end in FIG. 1 the connector housing 12 has its outer surface cut back to an inset area 68 with a plurality of annular grooves or sawtooth profile grooves 70 incised within an otherwise cylindrical surface 73 in the inset area. The surface extends past the grooves for a short distance in area 74 following which the housing has a bevel or camber 78 leading to the housing tip 79, forming the dielectric stress relief cone.

A moisture seal or cable entrance 80 comprising a generally tubular structure whose inner wall 81 is shaped to engage the outer surface of the housing over an extended area surface-to-surface contact within the inset and tapered area. The moisture seal has annular ridges 82 on its inner surface engageable with the housing grooves 70 to seal the joinder thereto.

The moisture seal 80 has a plurality of parallel ribs 84 in its inner wall 85 adjacent its opposite end 86 to mate with and seal the cable shield over an extended contact area.

This moisture seal 80 is fabricated of elastomeric conductive material. The conductive coating 88 on the exterior surface of the housing 12 is in intimate surface contact with the moisture seal to complete a conductive shielding path between the housing and the moisture seal.

The housing and moisture seal are elastomeric materials capable of being stretched into engagement with the cable, thereby producing a waterproof seal which does not require any taping.

The housing and moisture seal are also fabricated of elastomers having superior abrasion resistance, oil resistant and generally stable in the presence of corrosive influences.

In summary the invention has the following advantages:

This invention permits the use of the less expensive semiconductive coating method of shielding the connector, without requiring the expense and expertise needed for taping the juncture between the cable shielding and the connector shielding.

It also permits each basic connector housing to accommodate a greater range of cable diameters over semi-conductive shield, within their relatively flexible housings and mating cable entrance or moisture seal. For example, a connector housing could be used with different moisture seals to accommodate cables with different semi-conductive thicknesses.

Connector shielding is obtained by means of a semi-conductive coating. Mating with the cable receiving end of the connector is a separate watertight moisture seal or cable entrance made of a molded conductive or semi-conductive elastomer. The cable shield terminates within the molded watertight moisture seal or cable entrance, so that shielding is continuous between the cable and the watertight moisture seal or cable entrance. In addition, the semi-conductive coating of the connector underlays, and is in intimate contact with the moisture seal providing a continuous conductive path between connector coating and cable shield. The shielding then extends continuously from the cable shield to the semi-conductive coating on the connector.

Since the semi-conductive watertight moisture seal is a separate molded part, it can be sized to accommodate cables with various outside diameters, or shielding thicknesses, for each basic connector size.

The invention can be used any place that a shielded high-voltage cable is terminated to make a connection to a piece of apparatus, or to another cable.

While there has been described herein what is present thought to be a preferred embodiment of the invention, modifications may be made therein and it is my intent to cover in the appended claims all such modifications which fall within the true spirit and scope of the invention.

Claims

I claim:

1. An electrical connector structure for providing a waterproof electrical connection from the conductor of a high voltage shielded cable, wherein said cable has an outer conductive shield, an insulating sheath within said shield and an electrical conductor within the sheath, and wherein a section of the shield is removed to expose a section of the sheath, and a section of the sheath is removed to expose one end of said electrical conductor, a connection member for mechanically and electrically connecting to the one end of said conductor; the invention comprising: an elastomeric semi-conductive shielding member surrounding the exposed end of the conductor and said connecting member and engaging said cable sheath, a dielectric housing of waterproof elastomeric material surrounding said shielding member and engaging said sheath, a slip-on moisture sealing member of conductive elastomeric material sealingly engaging one end of said housing and said cable shield to cover the joinder of said cable to said housing, said sealing member forming a conductive connection to said cable conductive shield.

2. A structure as claimed in claim 1, wherein there is provided a conductive outer layer on said housing, said layer being in conductive contact with said sealing member to complete a conductive path through said sealing member to said cable conductive shield.

3. A structure as claimed in claim 1, wherein there is a load-break terminator electrode connected to said connector and extending out of said housing at the end opposite said cable.

4. An electrical connector structure for providing a shielded, waterproof electrical connection from the conductor of a high voltage shielded cable to a conductive member, wherein said cable conductor has a sheath of insulating material about said conductor and an electrically conductive shield surrounding the sheath, wherein a portion of the cable shield and sheath is removed to expose one end of the conductor, and wherein a conductive member is conductively connected to the exposed end of said conductor; the invention comprising: an elastomeric semi-conductive shield surrounding the connection of the conductor to said conductive member and extending into engagement with said cable sheath, a dielectric housing of waterproof elastomeric material closely surrounding said shield and engaging said cable sheath, a slip-on moisture sealing member of conductive elastomeric material sealingly engaging a side surface of said housing and said cable shield to waterproofingly cover the joinder of said cable to said housing, the body of said sealing member fitted about said housing between the ends of said sealing member, at least one rib on the inner wall of said sealing member engaging the outer surface of said cable shield to waterproofingly seal the joinder of the cable to the housing, and an exterior conductive surface on said housing in conductive engagement with said sealing member to complete a conductively shielding path therethrough from said housing surface to said cable shield, and means for grounding said cable shield.