PLUG MOUNTED SURGE ARRESTER

Abstract

A switch assembly including a switch and an interface physically coupled to the switch and configured to be physically coupled to an electrical component, such as a transformer. The switch assembly also includes an interface having electrical hardware electrically coupled to the switch and configured to be electrically coupled to the component. The switch assembly further includes a surge arrester having an insulation member, a grounding jacket formed over a portion of the insulation member and a conductor extending through the insulation member and being electrically coupled to the hardware and the grounding jacket. The interface further includes a releasable connector that is electrically coupled to the conductor and allows the surge arrester to be disconnected from the interface.

Claims

1. A switch assembly comprising: a switch; an interface physically coupled to the switch and configured to be physically coupled to an electrical component, the interface including electrical hardware electrically coupled to the switch and configured to be electrically coupled to the component; and a surge arrester including an insulation member, a grounding jacket formed over a portion of the insulation member and a conductor extending through the insulation member and being electrically coupled to the hardware and a grounding conductor and the grounding jacket.

2. The switch assembly according to claim 1 wherein the interface further includes a releasable connector that is electrically coupled to the conductor and allows the surge arrester to be disconnected from the interface.

3. The switch assembly according to claim 2 wherein the releasable connector is a Balseal garter spring.

4. The switch assembly according to claim 1 wherein the insulation member includes a tapered portion that extends into the interface, the conductor extending through and out of the tapered portion.

5. The switch assembly according to claim 1 wherein the insulation member is cylindrical.

6. The switch assembly according to claim wherein the insulation member is L-shaped.

7. The switch assembly according to claim 1 wherein the surge arrester includes a ground connector electrically coupled to the grounding jacket and including a pull hook.

8. The switch assembly according to claim 1 wherein the surge arrestor includes a plurality of metal oxide varistor discs electrically formed in the insulation member and being coupled between the grounding conductor and the conductor.

9. The switch assembly according to claim 1 wherein the switch is a bushing well interrupter.

10. The switch assembly according to claim 9 wherein the component is a transformer.

11. The switch assembly according to claim 10 wherein the transformer is part of an underground residential loop circuit.

12. A switch assembly comprising: a switch; an interface physically coupled to the switch and configured to be physically coupled to an electrical component, the interface including electrical hardware electrically coupled to the switch and configured to be electrically coupled to the component and a releasable connector that is electrically coupled to the conductor; and a surge arrester including a cylindrical insulation member, a grounding jacket formed over a portion of the insulation member and a conductor extending through the insulation member and being electrically coupled to the hardware and the grounding jacket, wherein the insulation member includes a tapered portion that extends into the interface, the conductor extending through and out of the tapered portion, and wherein the releasable connector allows the surge arrester to be disconnected from the interface.

13. The switch assembly according to claim 12 wherein the releasable connector is a Balseal garter spring.

14. The switch assembly according to claim 12 wherein the surge arrester includes a ground connector electrically coupled to the grounding jacket and including a pull hook.

15. A bushing well interrupter assembly comprising: a bushing well interrupter; a transformer interface physically coupled to the bushing well interrupter and configured to be physically coupled to a transformer, the interface including electrical hardware electrically coupled to the bushing well interrupter and configured to be electrically coupled to the transformer and a releasable connector that is electrically coupled to the conductor; and a surge arrester including an insulation member, a grounding jacket formed over a portion of the insulation member and a conductor extending through the insulation member and being electrically coupled to the hardware and the grounding jacket, wherein the releasable connector allows the surge arrester to be disconnected from the interface.

16. The assembly according to claim 15 wherein the insulation member includes a tapered portion that extends into the interface, the conductor extending through and out of the tapered portion.

17. The assembly according to claim 15 wherein the insulation member is cylindrical.

18. The assembly according to claim 15 wherein the insulation member is L-shaped.

19. The assembly according to claim 15 wherein the surge arrester includes a ground connector electrically coupled to the grounding jacket and including a pull hook.

20. The assembly according to claim 15 wherein the surge arrestor includes a plurality of metal oxide varistor discs electrically formed in the insulation member and being coupled between the grounding jacket and the conductor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is an isometric view of a pad mounted transformer employed in an underground residential loop circuit;

[0011] FIG. 2 is a front view of the transformer shown in FIG. 1;

[0012] FIG. 3 is a cross-sectional view of a portion of a bushing well interrupter assembly shown in FIGS. 1 and 2 including a transformer interface having an insulating plug;

[0013] FIG. 4 is a cross-sectional view of the portion of the bushing well interrupter assembly shown in FIG. 3 with the insulating plug replaced with a plug-mounted surge arrester;

[0014] FIG. 5 is a cross-sectional view of the plug-mounted surge arrester separated from the bushing well interrupter assembly; and

[0015] FIG. 6 is a cross-sectional view of an elbow shaped plug-mounted surge arrester.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following discussion of the embodiments of the disclosure directed to a plug-mounted surge arrester is merely exemplary in nature and is in no way intended to limit the invention or its applications or uses. For example, the plug-mounted surge arresters discussed herein have particular application for being employed in a transformer interface associated with a bushing well interrupter assembly that is part of a transformer employed in underground residential loop circuits. However, the plug-mounted surge arrester may have other applications.

[0017] FIG. 1 is an isometric view and FIG. 2 is a front view of a transformer 10 of the type that is mounted on a pad 12 that may be employed in an underground single-phase lateral loop circuit that feeds residential and commercial customers. The transformer 10 includes an enclosure 14 that houses the transformer primary and secondary coils (not shown) and other electrical components (not shown) of the transformer 10. A cover of the enclosure 14 has been removed to expose a panel 16 in the enclosure 14. A connector bushing 20 positioned within and coupled to a bushing well 18 extends through the panel 16 that accepts a bushing well interrupter assembly 22 that connects a power line 24 having an elbow connector 26 to one side of the primary coil and a connector bushing 30 positioned within and coupled to a bushing well 28 extends through the panel 16 that accepts a bushing well interrupter assembly 32 that connects a power line 34 having an elbow connector 36 to the other side of the primary coil, where the bushing well interrupter assemblies 22 and 32 are configured to provide automatic protection, isolation and power restoration of a lateral loop circuit without handling cable elbows. It is noted that the assemblies 22 and 32 are mirror images of each other to accommodate spacing for the existing features on the transformer 10. The assemblies 22 and 32 each include a bushing well interrupter 40 having a manual handle 48, a load-break interface 42, a transformer interface 46. A 120 V positive connector 50 is coupled to the secondary coil through a connector bushing 52 in the panel 16, a 120 V negative connector 54 is coupled to the secondary coil through a connector bushing 56 in the panel 16, and a neutral connector 58 is coupled to the secondary coil through a connector bushing 60 in the panel 16. Customer service lines 62 are connected to the connectors 50, 54 and 58 to deliver low voltage power to the desired number of loads (not shown). In this example, the lines 24, 34 and 62 run underground.

[0018] FIG. 3 is a cross-sectional view of a portion of the bushing well interrupter assembly 22. The transformer interface 46 includes coupling hardware having a conductive rod 80 and an adapter 82 that electrically couples the primary coil (not shown) in the transformer 10 to a power line 84 in the load-break interface 42 through the bushing well interrupter 40. An insulating plug 88 is inserted into the transformer interface 46 and is coupled to the conductive rod 80 by an insulating fiberglass rod 90 extending through the plug 88 and a cylindrical rod 94 through a releasable connector 92 including an annular rim formed to an inside of the rod 94 and an annular recess in the rod 90, sometimes known as a Balseal garter spring, providing a snap fit connection. The plug 88 is made of an EPDM rubber and is tapered to match the geometry of the interface 46, where the rod 90 and the plug 88 are chemically bonded. A removable grounded cap 96 covers the plug 88, where the grounded cap 96 would be electrically coupled to ground by, for example, a wire (not shown). The cap 96 and the plug 92 can be removed from the transformer interface 46 by disconnecting the releasable connector 92 to gain access to the coupling hardware.

[0019] FIG. 4 is a cross-sectional view of the bushing well interrupter assembly 22 as shown in FIG. 3, but where the insulating plug 88 and the grounded cap 96 have been replaced with a plug-mounted surge arrester 100. FIG. 5 is a cross-sectional view of the surge arrester 100 separated from the interface 46. The surge arrester 100 includes a cylindrical insulation 102 having a plug interface 104 that is the same size and shape as the plug 88, where the insulation 102 extends out of the interface 46. An outer grounded jacket 106 is bonded to the insulation 102 and is electrically coupled to a ground connector 108 having a pull hook 110 for removing the surge arrester 100 from the transformer interface 46, where the connector 108 would be electrically coupled to ground by, for example, a wire (not shown). A conductor 112 extends through the plug interface 104 and is electrically coupled to the conductor 94 through the connector 92. A series of spaced apart metal oxide varistor discs 114, here four, are molded into the insulation 102 and are electrically coupled to the ground connector 108 and the conductor 112. If a power surge occurs on the power line 84, it is sent through the discs 114 to ground.

[0020] FIG. 6 is a cross-sectional view of an elbow shaped plug-mounted surge arrester 130 that can be employed in these or other types of switching devices. The surge arrester 130 includes an L-shaped insulation 132 having a plug interface 134, where an outer grounded jacket 136 is bonded to the insulation 132 and is electrically coupled to a ground connector 138. A conductor 140 having an annular recess 142 for accepting a connector in a snap fit engagement extends into the plug interface 134 so that the recess 142 is exposed. The conductor 140 is electrically coupled to a conductor 144 by a lug connector 146 to provide the L-shape. The conductor 144 is electrically coupled to a series of metal oxide varistor discs 148 that are also electrically coupled to the ground connector 138.

[0021] The foregoing discussion discloses and describes merely exemplary embodiments of the present disclosure. One skilled in the art will readily recognize from such discussion and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the spirit and scope of the disclosure as defined in the following claims.