The invention relates generally to separable loadbreak connector systems for electric power systems, aid more particularly to insulated loadbreak connector systems to interface deadfront electrical apparatus and power distribution cables. Electrical power is typically transmitted from substations through cables which interconnect other cables and electrical apparatus in a power distribution network. The cables are typically terminated on bushings that may pass through walls of metal encased equipment such as capacitors, transformers or switchgear.
Because of increased safety, increased reliability and increased operability of the deadfront system, deadfront electrical apparatus is increasingly being used in lieu of livefront apparatus. Using a deadfront system, because there is no exposed voltage, safety is increased for both the operator and the public, and the ability to operate the apparatus easily and efficiently either with grounded, visible break connection points or loadbreak connection points with a one or two man crew lessens the operating danger. The deadfront system has proven to be extremely reliable with very low failure rate.
Various safety codes and operating procedures for underground power systems require a visible break disconnect for safely performing routine maintenance work on the cable system, such as line energization checks, grounding, fault location, or hi-potting, may also be required. High voltage, separable connector systems have been developed that allow disconnection of the electrical path from a deadfront apparatus to the feeder cables connected to the apparatus bushings without moving the feeder cables and while providing visible-break isolation. Connector systems are known including a removable link or positionable connector assembly extending between a deadfront junction mounted to the electrical apparatus proximate the bushing of the apparatus and a mating connector joined to a cable. When the linking assembly is removed and the connector assembly is repositioned, the visible link is immediately recognizable. While such connector systems for deadfront apparatus can be effective to provide the visible break, they can be complicated to use, and generally require that the cables be de-energized prior to operation of the connectors. It would be desirable to provide a deadfront visible break that can be operated while the cables are energized, especially for medium voltage switchgear apparatus and the like.
Additionally, known separable loadbreak connectors are operable in “loadmake”, “loadbreak”, and “fault closure” conditions. Considerable arcing can occur in any of the operating conditions when energized connectors are joined and separated. It would be desirable to reduce arcing intensity as the connectors are mated and separated.
According to an exemplary embodiment, an insulated, deadfront loadbreak connector system is provided. The system comprises first and second mating connector assemblies configured to make or break an electrical connection under energized circuit conditions, and the first and second mating connectors are selectively postionable relative to one another. One of the first and second mating connectors includes an arc follower, and the other of the first and second mating connectors includes an arc interrupter configured to receive the arc follower. The First and second mating connectors are positionable in a disconnected position wherein an end of the arc follower remains interior to the other of the first and second connectors.
According to another embodiment, an insulated, deadfront loadbreak connector system comprises first and second mating connector assemblies configured to make or break an electrical connection under energized circuit conditions. One of the first and second connector assemblies is stationary and the other of the first and second connector assemblies is movable, wherein one of the first and second connectors includes first and second substantially parallel interfaces connected by a bus, thereby distributing arc energy among at least two different locations during operation of the connectors.
According to another embodiment, an insulated, separable connector system comprises first and second mating connector assemblies configured to make or break an electrical connection to a deadfront electrical apparatus under energized circuit conditions. One of the first and second connector assemblies is stationary and the other of the first and second connector assemblies is movable. One of the mating connector assemblies comprising a contact element configured to make and break one of an energized connection under a normal load current and an energized connection that is not under a normal load current. At least one of an actuating element to engage or disengage the mating connector assemblies and a slidable positioning element configured to align the mating connector assemblies is also provided.
According to another embodiment, a method of visibly breaking an electrical connection to a deadfront electrical apparatus is provided. The method comprises providing first and second electrical connectors, one of the connectors being fixed to the apparatus and the other of the connectors movable thereto, and one of the connectors including an arc follower and the other of the connectors including an arc interrupter. The method also includes joining the first and second electrical connectors under energized circuit conditions to complete the electrical connection to the apparatus, separating the first and second electrical connectors to disconnect the electrical connection to the apparatus, and limiting the separation of the first and second electrical connectors so that the arc follower remains within the arc interrupter and arc energy substantially remains in an interior of the connectors.
According to another embodiment, a method of visibly breaking an electrical connection to a deadfront electrical apparatus is provided. The method comprises providing first and second electrical connector assemblies, at least one of the connectors having first and second contact elements connected to a bus, thereby providing a series connection between the first and second contact elements. The method also includes joining the first and second electrical connectors under energized circuit conditions to complete the electrical connection to the apparatus, and simultaneously breaking electrical arcing at the first and second contact element.
According to still another exemplary embodiment, a separable loadbreak connector system comprises means for completing and breaking an electrical connection under energized circuit conditions and means for distributing arc energy, connected to the means for completing and breaking, at more than one location. Means for positioning the means for completing and breaking to complete and break the electrical connection are also provided.
As shown in
While the female connector 102 is illustrated as an elbow connector in
In an exemplary embodiment, and as shown in
The male connector 104 may be a bushing insert composed of a shield assembly 130 having an elongated body including an inner rigid, metallic, electrically conductive sleeve or contact tube 132 having a non-conductive nose piece 134 secured to one end of the contact tube 132, and elastomeric insulating material 136 surrounding and bonded to the outer surface of the contact tube 132 and a portion of the nose piece 134.
A contact assembly including 102, a female contact 138 having deflectable contact fingers 140 is positioned within the contact tube 132, and an arc interrupter 142 is provided proximate the female contact 138.
The female and male connectors 102, 104 are operable or matable during “loadmake”, “loadbreak”, and “fault closure” conditions. Loadmake conditions occur when the one of the contact elements, such as the male contact element 114 is energized and the other of the contact elements, such as the female contact element 138 is engaged with a normal load. An arc of moderate intensity is struck between the contact elements 114, 138 as they approach one another and until joinder under loadmake conditions. Loadbreak conditions occur when the mated male and female contact elements 114, 138 are separated when energized and supplying power to a normal load. Moderate intensity arcing again occurs between the contact elements 114, 138 from the point of separation thereof until they are somewhat removed from one another. Fault closure conditions occur when the male and female contact elements 114, 138 are mated with one of the contacts being energized and the other being engaged with a load having a fault, such as a short circuit condition. Substantial arcing occurs between the contact elements 114, 138 in fault closure conditions as the contact elements approach one another they are joined. In accordance with known connectors, arc-quenching gas is employed to accelerate the female contact 138 in the direction of the male contact element 114 as the connectors 102, 104 are engaged, thus minimizing arcing time and hazardous conditions. The arc interrupter 142 is sized and dimensioned to receive the arc follower 120. The arc interrupter 142 generates arc-quenching gas to extinguish arcing when the probe 114 is separated fi-om the female contact 138.
In an exemplary embodiment, the movable connector assembly 164 includes ganged female connectors 170, 171 that may be, for example, similar to the female elbow connector 102 illustrated in
The fixed connector assembly 162, in an exemplary embodiment includes stationary male connectors 182, 183 that correspond to and are aligned with the female connectors 170, 171. The male connectors 182, 183 may each be, for example, similar to the male connector 104 shown in
The male connectors 182, 183 may be mounted in a stationary manner to a mounting plate (not shown in
In the separated position, the mating interfaces 184 of the female connectors 170, 171 and mating interfaces 186 of the male connectors 182, 183 are accessible for service and repair. The position of the movable connector assembly 164 in relation to the fixed connector assembly 162 provides a visible break to verify disconnection of the cable associated with the connector 183 from, for example, a deadfront electrical apparatus.
A positioning/actuating mechanism 166 is fastened to a central portion of the connector housing 172 and is attached thereto with an adapter plate 192 and known fasteners. In use, the mechanism 166 is configured to cause the connector assembly 164 to move away from the male connectors 182, 183 in the direction of arrow B. In an exemplary embodiment, the mechanism 166 is a stored energy device having concentric telescoping members 194, 196 slidably engaged to one another and positionable in a retracted position (shown in
In an exemplary embodiment, an actuating or release element, internal to the mechanism 166, may be mounted to one or more of the telescoping members to bias the telescoping members in the direction of arrow B. Stop features, such as pins or detents, may be provided so that the telescoping members 194, 196 may be extended to, but not beyond a predetermined distance in the extended position. The stop features may be chosen so that the arc followers 120 of the female connectors 170, 171 remain partially engaged to the male connectors 182, 183 in a disconnected position wherein the conductive path between the male and female connectors is broken, while a portion of the arc followers 120 remain in the arc interrupters 142 interior to the male connectors 182, 183 in a as shown in
In an exemplary embodiment, the release element may be a compressible spring element that is loaded in compression as the telescoping members 194, 196 are retracted, although it is understood that in an alternative embodiment, the release element could be loaded in tension. Once released, the force stored in the spring actuates or extends the telescoping members 194, 196 to the extended position wherein the connector assembly 164 is moved in the direction of arrow B for a sufficient distance to disengage or disconnect a conductive path through the male and female contacts, but an insufficient distance to mechanically separate the arc followers 120 from the arc interrupters 142 of the male connectors 182, 183. That is, the release distance is selected to keep the arc follower 120 at least partially contained within the arc interrupter 142 of each connector in the extended position. In one embodiment the telescoping members 194, 196 of the mechanism 166 are extended outwardly an axial distance of about 6.5 inches from the retracted position (
In an exemplary embodiment, and as shown in
Additionally, after initial alignment of the connector assembly 164 with the male connectors 182, 183, the connector assembly 164 is maintained in alignment by virtue of the arc followers 120 never completely separating from the male connectors 182, 183 in use. Thus, an external alignment mechanism, is not needed to safely align and operate the male and female connectors. The mechanism 166 both maintains the alignment of the connectors and actuates them to the disconnected position when released.
While an exemplary positioning/actuating mechanism 166 is illustrated in
In further and/or alternative embodiments, other actuating elements may be provided to engage or disengage the movable connector assembly 164 to and from the fixed connector assembly 162. The actuating element may be for example, a motorized mechanism, a hydraulic mechanism, a pneumatic mechanism, a draw-out mechanism, or other known device that is operatively connected to the assembly 164 to engage or disengage the assembly connectors 170, 171 and 182, 183. The actuating element may provide for remote actuation of the system 160 as desired, and may -also prevent or limit movement of the connector assembly 164 relative to the connector assembly 162. Additionally, other positioning elements may be provided such as, for example, rails upon which the connectors may slide relative to one another while assuring proper alignment of the connectors in the system.
EPDM rubber insulation, for example, may surround the conductive bus 200, the adapters 202, and may define the interfaces 184 that receive the male connectors 181, 183. Ground shields 204 may be provided on the outer surfaces of the housings 170, 171, and the connector housing 172 as desired.
While the assembly 164 is formed into a U-shaped configuration having substantially equal legs in one embodiment as shown in
Notably, and unlike known connector systems, the connector assembly 164 permits load breaking and load making with reduced arc intensity. By connecting the probes 114 in series to one another via the bus 200, the electrical making and breaking is distributed among multiple locations rather than in a single location. That is, because of the series connection provided by the bus 200, the arcs occur at the ends of each probe 114 rather than solely at the end of a single probe. By distributing the arc along two locations, a reduced arc intensity is seen at each probe in the interfaces 184. By reducing the arc intensity, the connector system 160 is generally safer to use than known systems. This is especially so when the system 160 is used in the manner shown in
While the exemplary method of safe break disconnection is described in the context of the ranged connector assembly 164, it is appreciated that the method could be practiced in systems having a single loadbreak location as well. That is, the method is believed to be advantageous for single male and female loadbreak connections under electrical load.
In an exemplary embodiment the connector assembly 164 is a 600 A, 21.1 kV class loadbreak connector for use with medium voltage switchgear or other electrical apparatus in a power distribution network of above 600V. It is appreciated, however, that the connector concepts described herein could be used in other types of connectors and in other types of distribution systems, such as high voltage systems, as desired.
In an exemplary embodiment, the movable connector assembly 224 includes ganged female connectors 230, 231 that may be, for example, similar to the connectors 170, 171 illustrated in
The fixed connector assembly 222, in an exemplary embodiment, includes a mounting plate 240, and male connectors 242, 243 that correspond to and are aligned with the female connectors 230, 231, respectively. In an exemplary embodiment, the connector 242 may be connected to a vacuum switch or interrupter assembly (not shown) that is, for example, part of a deadfront electrical apparatus in a power distribution network, and the connector 243 may be connected to a power cable in a known manner, with or without additional bushings and connectors as those in the art may appreciate.
The mounting plate 240 secures the male connectors 242, 243 in a spaced apart manner aligned with the female connectors 230, 231 such that, when the female connectors 230, 231 are moved along the assembly longitudinal axis 234 in the direction of arrow C, the male connectors 242, 243 maybe securely engaged to the respective male connectors 230, 231. Likewise, when the female connectors 230, 231 are moved in the direction of arrow D, opposite to the direction of arrow C, the female connectors 230, 231 may be disengaged from the respective male connectors 242, 243 to a separated position as shown in
In the separated position, the mating interfaces 244 of the female connectors 230, 231 and mating interfaces 246 of the male connectors 242, 243 are accessible for service and repair, in a further embodiment, a portion of the assembly 220 maybe pivotable about a pivot axis, such as the axis 248, to turn or rotate the female connectors 230, 231 relative to the male connectors 242, 243 in the direction of arrow E to provide even greater accessibility to the connector interfaces 244 and 246. The position of the movable connector assembly 224 in relation to the fixed connector assembly 222 provides a visible break to verify disconnection of the cable associated with the connector 243 from the deadfront electrical apparatus.
The positioning mechanism 226 may be, as shown in
In a further embodiment, an actuating element 260 may be provided to engage or disengage the movable connector assembly 224 to and from the fixed connector assembly 222. The actuating element 260 may be for example, a motorized mechanism, a hydraulic mechanism, a pneumatic mechanism, a draw-out mechanism, or other known device that is operatively connected to the assembly 224 to engage or disengage the assembly connectors. The actuating element 260 may provide for remote actuation of the system 220 as desired, and may also prevent or limit movement of the connector assembly 224 relative to the connector assembly 222. Still further, the actuating element 260 may be a stored energy device, such as a spring assisted mechanism or other known mechanism, that facilitates rapid connection or disconnection of energized components of the connector system, thereby minimizing a duration of electrical arcing that occurs when the energized connectors are engaged and/or disengaged.
While an exemplary positioning mechanism 226 in the form of rails 252, 254 and associated components is illustrated in
Like the foregoing system 160, and as best seen in
While the exemplary method of safe break disconnection is described in the context of the ganged connector assembly 224, it is appreciated that the method could be practiced in systems having a single loadbreak location as well. That is, the method is believed to be advantageous for single male and female loadbreak connections under electrical load.
In an exemplary embodiment the connector assembly 224 is a 200 A, 25 kV class loadbreak connector for use with medium voltage switchgear or other electrical apparatus in a power distribution network of above 600V. It is appreciated, however, that the connector concepts described herein could be used in other types of connectors and in other types of distribution systems, such as high voltage systems, as desired.
The combination of distributed arc energy among more than one location, together with the above-described safe break positions wherein the electrical path is disconnected while containing substantially all of the arc energy interior to the connectors, results in safer and more reliable loadbreak connector systems with visible break for deadfront electrical apparatus.
EPDM rubber insulation, for example, may surround the conductive bus 290, the adapters 296 and may define interfaces that receive male connectors 182, 183 (
While the assembly 280 is formed into a U-shaped configuration having substantially equal legs in one embodiment as shown in
Notably, and unlike the prior connector assemblies 164 (
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
This patent application is a continuation of co-pending U.S. patent application Ser. No. 12/126,266, entitled “Apparatus, Systems and Methods for Deadfront Visible Loadbreak,” filed May 23, 2008, which is a continuation of U.S. Pat. No. 7,384,287, entitled “Apparatus, Systems and Methods for Deadfront Visible Loadbreak.” The complete disclosure of each of the foregoing priority applications is hereby fully incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
Parent | 12126266 | May 2008 | US |
Child | 12274816 | US | |
Parent | 11199051 | Aug 2005 | US |
Child | 12126266 | US |