Patent Description:
In medium voltage (MV) switchgear applications, voltage and control power (CP) transformers may be mounted vertically next to each other in a compartment(s) (e.g., a cubicle(s)) of a cabinet of a switchgear (also referred to as a switchgear assembly). The primary connection to these transformers is typically cables or buses, which are connected to the line or load side bus within the switchgear. When a common source is required for both of the transformers, a bus or cable connection is also made between each component. These bus or cable connections in <NUM>,<NUM> volt applications may require a certain air gap or insulating means to properly manage the required electrical clearances. Because of the complexity of these bus and cable connections, the primary compartment or area designated for making these connections can have a depth of at least <NUM> to <NUM> inches. A connector assembly according to the preamble of independent claim <NUM> is disclosed in <CIT>. Further connector assemblies are disclosed by <CIT>, <CIT>, <CIT> and <CIT>.

To address these and other shortcomings, a connector assembly according to independent claim <NUM> is provided. In accordance with an embodiment, the connector assemblyincludes the first and second bushing assemblies. Each of the first and second bushing assemblies include: the bushing having the opposing first and second open ends with the cavity extending therethrough, the cavity being separated by the wall into the first and second cavities which open to the first and second open ends respectively, the wall having the opening extending between the first and second cavities, wherein the bushing can be formed of an insulating material; the connector formed of the conductive material and arranged in the cavity, the connector having the portion extending through the opening of the interior wall, wherein the connector can have a first end with a first terminal in the first cavity of the bushing and the opposing second end in the second cavity; and the flexible joint cover connectable over the portion of the bushing to enclose the second cavity with the second end of the connector, wherein the flexible joint cover having the first slot through which to receive the conductor from a line or load bus for connection to the second end. The connector assembly further includes the tubing, connected between the flexible joint covers of the first and second bushing assemblies, the tube housing the conductive cable which is connected between the second ends of the connectors of the first and second bushing assemblies.

In some embodiments, the second end of the connector can include at least two second terminals separated from each other. The conductive cable can be connected between one of the two second terminals of the first bushing assembly and one of the two second terminals of the second bushing assembly.

The various embodiments, the first terminal of the connector for each of the first and second bushing assemblies can be configured to connect to a terminal of a device in a compartment of a switchgear cabinet of a switchgear assembly. The first device can be a control power transformer or a voltage transformer. The first and second bushing assemblies along with the tubing can utilize <NUM> or fewer inches in depth of a primary compartment of the switchgear cabinet to electrically connect a line or load bus to the first device. The first and second bushing assemblies together with the tubing can be configured to operate in a voltage class of 15kV, 95kV Basic Insulation Level (BIL).

In some embodiments, the flexible joint cover can be a polyvinyl chloride (PVC) boot which is detachably connectable over the portion of the bushing to enclose the second cavity with the second end. The tubing can be a phenolic tube. Each connector of the first and second bushing assemblies can have a Z-shape.

In accordance with a further embodiment, a switchgear assembly can include: a switchgear cabinet including an auxiliary compartment, a cable compartment and a bus bar compartment; a multi-phase power bus system including line and load buses for distributing multi-phase power; a first device in the auxiliary compartment of the switchgear cabinet; and a plurality of the connector assemblies each for a respective power phase, each of the connecter assemblies having the first terminal of the connector of one of the first or second bushing assembly connected to the first device for a respective power phase and the second end of the connector of the first or second bushing assembly connected to a respective power phase of the line or load bus of the multi-phase power bus system.

In some embodiments, the switchgear assembly can further include a second device in the auxiliary compartment of the switchgear cabinet, and the first and second devices can be mounted vertically next to one another in the auxiliary compartment. Each of the connector assemblies can have the first terminal of the other one of the first or second bushing assembly connected to the second device for a respective power phase. Furthermore, the first device can be a control power transformer and the second device is a voltage transformer. The first and second bushing assemblies along with the tubing can utilize <NUM> or fewer inches in depth of the switchgear cabinet to electrically connect a line or load bus to the first device. Each of the connector assemblies can be configured to operate in a voltage class of 15kV, 95kV Basic Insulation Level (BIL).

A compact auxiliary connector includes two bushings each with an electrical connector(s), and a tubing (or "tube") connected between the two bushings to insulate an electrical cable, which is connected between electrical connectors of the two bushings. The electrical connector of each of the two bushings can be connected to an electrical device, a bus (e.g., for line or load) or a combination thereof, according to the desired connection configuration. Each bushing also includes a flexible joint cover, such as a boot, to cover the connection of the bushing connectors to a bus, such as a primary bus. The compact auxiliary connector can manage live connections between auxiliary or other device(s) and line/load buses in a switchgear cabinet (or enclosure) of a switchgear assembly. The bushings, tubing and flexible joint cover can be formed of insulating materials having desired dielectric strength according to the voltage applications.

The compact auxiliary connector of the present disclosure can allow a significant reduction in parts and compartment size for supporting, for example, medium voltage primary connections to auxiliary transformers. This reduction is valuable in allowing a reduced equipment depth while maintaining a safe and reliable live part connection in small enclosures. For example, the use of such compact auxiliary connectors as described herein can be more economical than using increased enclosure size with bus bars and insulators. Furthermore, the design of the connector assembly can also sufficiently manage strike and tracking distances and dielectric strength at desired rated voltage, such as for medium or other voltage applications (e.g., 15kV, 95kV Basic Insulation Level (BIL) applications). The compact auxiliary connector can also allow live parts to be safely mounted within a compartment of <NUM> inches (or <NUM>) of grounded metal. The compact auxiliary connector can provide adequate air clearances between live parts and grounded metal to avoid dangerous potential partial discharge issues.

An example compact auxiliary connector will be described below with reference to the figures, in accordance with the present disclosure.

<FIG> shows a partial view of an example switchgear assembly <NUM>, which includes a switchgear cabinet <NUM> for housing switching and auxiliary devices, electrical connectors/cabling and bus bars. In this example, the switchgear assembly <NUM> is for a multi-phase power distribution system, such as a three-phase power distribution system. The switchgear cabinet <NUM> can include a plurality of compartments for housing switching and/or auxiliary devices, electrical cables and conductors, bus bars for line and load, and other components. The compartments can, for example, include: a switching and/or auxiliary compartment(s) <NUM> for housing switching and/or auxiliary electrical device(s) such as circuit breakers, transformers and other protective devices; a bus bar compartment(s) <NUM> (not shown) for housing line and load bus bars connected to a power source and various loads, respectively; and a cable compartment(s) <NUM> for housing conductors or electrical cables (generally referred to as cables) which connect various devices, bus bars and other components in the switchgear cabinet <NUM>. In this example, the auxiliary compartment(s) can house auxiliary devices, such as a control power (CP) transformer <NUM> and a voltage transformer <NUM>, which are vertically stacked, e.g., one above the other, in the auxiliary compartment(s) <NUM> of the switchgear cabinet <NUM>. A compartment <NUM>, which is referred to as a primary compartment, is where connection is made between electrical equipment (e.g., medium voltage equipment) and a primary bus <NUM>.

As further shown in <FIG>, a compact auxiliary connector <NUM> is provided for each power phase to electrically connect the transformers <NUM> and <NUM> and a bus, such as the primary bus <NUM>, to each other. As shown in <FIG> and <FIG>, the primary bus <NUM> (e.g., of a line bus), for each phase can be connected to a respective compact auxiliary connector <NUM>. An epoxy can be applied to a portion of a conductor <NUM> of the primary bus <NUM>, which would otherwise be exposed, when connected to the compact auxiliary connector <NUM> in the primary compartment <NUM>. The conductor <NUM> can be a flat conductor with one end connected or connectable to a cable of the primary bus <NUM>, and the other end connectable to the compact auxiliary connector <NUM> (or a conductor therein). The epoxy can be formed of a dielectric material or other insulating material. The primary compartment <NUM> can have a depth D, as shown in <FIG>.

<FIG> illustrates a perspective view of the plurality of compact auxiliary connector(s) <NUM> of <FIG> with a portion of bushing assemblies of one of the connectors cut out to provide an internal view of the connectors and components therein, in accordance with an embodiment. As shown in <FIG>, each compact auxiliary connector <NUM> includes two bushing assemblies 300A, 300B (each assembly also referred generally as "<NUM>"). Each bushing assembly 300A, 300B includes a bushing <NUM> with an electrical connector <NUM> therein, and a flexible joint cover <NUM> for covering a portion of the bushing <NUM> and connections therein. The compact auxiliary connector <NUM> also includes tubing (or tube) <NUM> which is connected between the two bushing assemblies 300A and 300B and houses an electrical cable <NUM> which is connected between the electrical connectors <NUM> of the two bushing assemblies 310A, 310B. Although the tubing <NUM> is shown as being cylindrical in shape, the tubing <NUM> can have any suitable shape, size and/or length according to the application. The tubing <NUM> can be formed of an insulating material. In this example, the tubing <NUM> can be a phenolic tubing.

As further shown in <FIG>, the bushing <NUM> includes a cavity <NUM> therein. The bushing <NUM> also includes a wall <NUM> (e.g., wall, partition, etc.), which separates the cavity <NUM> into a first cavity 410A and a second cavity 410B each of which open to first and second open ends respectively. The wall <NUM> includes an opening <NUM>, which extends between the first and second cavities 410A and 410B and receives a portion of the connector <NUM> therethrough. The bushing <NUM> also includes an opening <NUM> for receiving an open-end portion of the tubing <NUM>. The bushing <NUM> can be formed of an insulating material. The bushing <NUM> can have a generally cylindrical shape. In this example, the first cavity 410A has a cross-sectional area, which is smaller than the second cavity 410B (e.g., the diameter of the first cavity 410A is smaller than the diameter of the second cavity 410B). The bushing <NUM> and portion thereof can be a rigid component, which can have any desired size, shape or dimension depending on the application. For example, the size and shape of the open-ended portion of the bushing <NUM> with the first cavity 410A can be configured to engage a connector assembly of devices connectable thereto, such as the auxiliary and other devices, described herein. When connected, the device connection to the connector <NUM> is covered. The bushing <NUM> can be formed as a single (or unitary piece) or multiple pieces connected together.

The connector <NUM> is formed of a conductive material, and has a first end <NUM> and a second end <NUM>. The connector <NUM> has a portion thereof, which extends through the opening <NUM> of the wall <NUM> and is supported by the wall <NUM>. The first end <NUM> of the connector <NUM> is arranged in the first cavity 410A, and the second end <NUM> of the connector <NUM> is arranged in the second cavity 410B. The first end <NUM> includes a first terminal <NUM> for connecting to a conductor. In this example, the first terminal <NUM> can be configured to connect to an electrical device, such as an auxiliary or other device of a switchgear assembly (e.g., transformer). The second end <NUM> can include a plurality of terminals, such as for example two separate second terminals 432A, 432B. In this example, the second terminal 432A can be configured to connect to a bus conductor, such as for example, the conductor <NUM> of the primary bus <NUM>. The other second terminal 432B can be configured to connect to a conductor, such as the cable <NUM> which is connected between the second terminals 432B of the connectors <NUM> of the two bushing assemblies 310A, 310B (e.g., in <FIG>). The first and second terminals can employ various electrical fasteners or fastening configurations to connect the connector <NUM> to a conductor of a device, bus or other electrical component. In this example, the connector <NUM> is a flat conductor with a Z-shape; however, the connector <NUM> can have any suitable size and shape depending on the application.

The flexible joint cover <NUM> is configured to connect over a portion of the bushing <NUM> to enclose the second cavity 410B with the second end <NUM> of the connector <NUM> and cover any connection to the second end <NUM>. The joint flexible cover <NUM> includes a first extending portion <NUM> with a slot <NUM> through which to receive a conductor, such as for example from a line or load bus for connection to the second end <NUM> in the cavity 410B of the bushing <NUM>. In this example, the conductor is the conductor <NUM> of the primary bus <NUM>. The first extending portion <NUM> can have a rectangular shape. The flexible joint cover <NUM> also includes a second extending portion <NUM> with a channel <NUM> for receiving an end portion of the tubing <NUM>, which has portion thereof engaged through the opening <NUM> of the bushing <NUM>. The walls of the extending portion <NUM> may extend fully or partially around the portion of the tubing <NUM>. In this example, the extending portion <NUM> extends partially around the portion of the tubing <NUM> to allow removal of the flexible joint cover <NUM> even when the tubing <NUM> is engaged in the opening <NUM> of the bushing <NUM>. The flexible joint cover <NUM> can take the form of a boot which can be detachably connectable over an open portion of the bushing <NUM> to cover a connection(s) to the second end <NUM> of the connector <NUM>, and can be made of Polyvinyl Chloride (PVC) or other flexible insulating material.

An operational installation example is described below with reference to the components of the switchgear assembly <NUM> of <FIG>. In this example, the control power transformer <NUM> is vertically stacked on top of the voltage transformer <NUM> in the cabinet <NUM>. For each phase, the first end <NUM> of the connectors <NUM> of the bushing assemblies <NUM> (e.g., 300A and 300B) of one compact auxiliary connector <NUM> is connected to a connection assembly (or conductor) of the transformers <NUM> and <NUM>, respectively. The conductor <NUM> of the primary bus <NUM> is extended through the slot <NUM> of the flexible joint cover <NUM>, and connected to the second terminal 432A of the connector <NUM> of one of the bushing assemblies (e.g., 300A) in the cavity 410B. The flexible joint cover <NUM> can then be pulled over a portion of the bushing <NUM> to enclose the cavity 410B and cover the connection to the second end <NUM> of the connector <NUM>. This process can be repeated with other compact auxiliary connectors <NUM> to make the connections for the other phases. The reverse process can be performed to disconnect the transformers <NUM> and <NUM> from the primary bus <NUM>. The above is simply one example of the different connection configurations, which can be made between device(s) and bus(es) in a switchgear assembly or other electrical enclosure. The compact auxiliary connector(s) <NUM> can be employed to connect different types and numbers of devices to different types and numbers of buses in a power distribution system.

In various embodiments, the compact auxiliary connector, described herein, can manage, among other things, the following: live part connection to an auxiliary device (e.g., transformer fuse of a transformer); live part connection to a primary bus; and cable connection housed in a phenolic tubing to make primary connection to two auxiliary devices (e.g., two transformers such as control power transformer and voltage transformer). Epoxy can be used on the primary bus coupled with a flexible joint cover (e.g., a boot) which can be made in a suitable size and dimension to cover an opening of the bushing and formed from a high dielectric strength flexible PVC material. The compact auxiliary connector can maintain required clearances and required tracking distance to perform in a 15kV, 95kvBIL application (or voltage class). Furthermore, the compact auxiliary connector can allow for a relatively small Medium Voltage (MV) primary compartment with a depth D at or around <NUM> inches (<NUM>,<NUM>) or less compared to a compartment depth on some other MV switchgear assemblies which may need <NUM> inches (<NUM>) using cables or buses. This represents a <NUM>% decrease in compartment size resulting in a smaller foot print for the switchgear cabinet or compartments therein.

It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the," and any singular use of any word, include plural referents unless expressly and unequivocally limited to one referent. As used herein, the term "include" and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

Claim 1:
A connector assembly (<NUM>) for connecting a bus to one or more auxiliary devices in a switchgear assembly (<NUM>), the connector assembly (<NUM>) comprising:
first (300A) and second (300B) bushing assemblies, comprising:
a bushing (<NUM>) having opposing first and second open ends with a cavity (<NUM>) extending therethrough, the cavity (<NUM>) being separated by a wall (<NUM>) into first (410A) and second (410B) cavities which open to first and second open ends respectively, the wall (<NUM>) having an opening (<NUM>) extending between the first (410A) and second (410B) cavities, and
a connector (<NUM>) formed of a conductive material and arranged in the cavity (<NUM>), the connector (<NUM>) having a portion extending through the opening (<NUM>) of the interior wall (<NUM>) and comprising a second end (<NUM>),
characterized in that
the first (300A) and second (300B) bushing assemblies further comprising a flexible joint cover (<NUM>) connectable over a portion of the bushing (<NUM>) to enclose the second cavity (410B) with the second end (<NUM>) of the connector (<NUM>), the flexible joint cover (<NUM>) having a first slot (<NUM>) through which to receive a conductor for connection to the second end (<NUM>), and
the connector assembly (<NUM>) further comprising a tubing (<NUM>), connected between the flexible joint covers (<NUM>) of the first (300A) and second (300B) bushing assemblies, the tubing (<NUM>) housing a conductive cable (<NUM>) which is connected between the second ends (<NUM>) of the connectors (<NUM>) of the first (300A) and second (300B) bushing assemblies.