Patent Application
20050270718
The present invention relates to a power switching device and more particularly to an electrical terminal conductor in the power switching device.
In the power generation and distribution industry, utility companies generate electricity and distribute the electricity to their customers. To facilitate the process of distributing electricity, various types of power switching devices are used. In a distribution circuit, electricity flows through the power switching devices from a power generation source (typically a substation or the like) to the consumer. When a fault is detected in the distribution circuit, the power switching device is opened and the electrical connection is broken.
Controllers are used by the utility company to detect faults that occur in the distribution circuit. The controller typically uses a microprocessor programmed to respond to the fault based on the type of fault and the type of power switching device connected to the controller. The controller may respond to a particular fault by causing the power switching device to remain open. Alternatively, upon the detection of a fault, the controller may cause the power switching device to open and close multiple times.
The typical voltage ratings for power switching devices range from 1 kilovolts (kV) to 38 kV with current levels up to 63,000 amperes. In order to withstand this amount of power, the power switching devices are constructed out of non-conductive materials such as epoxy or epoxy resins. As the power switching devices are manufactured, the conductive elements are placed within a mold and the non-conductive material, in liquid form, is poured into the mold. As the material cools it solidifies and holds the conductive elements in place. The conductive elements are connected to a connector that extends out of the epoxy housing.
The epoxy and the conductive element have two different coefficients of expansion. As a result, when the epoxy hardens it may not sufficiently adhere to the connector to properly secure the connector in the power switching device. Connectors that are now used in power switching devices are only cylindrical in form and thus the epoxy has only regularly shaped smooth surfaces to adhere to. The present invention provides an irregular shape to the connector to thereby allow additional surface area for the epoxy adhesion.
When the power switching device is wired into the power distribution network, cables are attached and tightened to the connector. The utility company provides guidelines to its personnel for the amount of force necessary to secure the cables. However, these guidelines may not be followed and too much force may be applied by utility personnel when securing the cables. If the connector is not sufficiently secured by the epoxy, the torque resulting from the excessive force may cause the connector to rotate. If the connector rotates, the structure of the power switching device is compromised and the device may experience premature failure. The present invention provides a secure anchor for the connector within the epoxy should excess amounts of torque be applied.
Additionally, during the installation process, compressional forces can be exerted on the connector. The compressional forces may compromise the integrity of the components connected to the connector. The connector of the present invention distributes the compressional forces away from the conductive elements within the power switching device.
A power switching device for use in transmitting and distributing power, the power switching device having a vacuum interrupter, a non-cylindrical conductor, one end of the non-cylindrical conductor electrically connected to a power source, the other end of the non-cylindrical conductor electrically connected to the vacuum interrupter, the non-cylindrical conductor and the vacuum interrupter are encased in a non-conductive housing.
A conductor for use in a power switching device, the power switching device being installed in a power distribution network, the conductor having a cylindrical portion, a base portion, and a protrusion. The protrusion is connected to the cylindrical portion and the base portion and the protrusion extending radially away from the cylindrical portion.
A power distribution network having a power source connected to a conductor of a power switching device, the conductor having a cylindrical portion, a base portion and a protrusion, the protrusion is connected to the cylindrical portion and the base portion, the protrusion radially extending away from the cylindrical portion.
The invention is further described in the detailed description that follows, by reference to the noted drawings by way of non-limiting illustrative embodiments of the invention, in which like reference numerals represent similar elements throughout the several views of the drawings, and wherein:
The power switching device 110 connects the power source 120 to the load 130. A power source 120 used with the present invention is a substation that provides, for example, a 15 kV-38 kV source of three phase AC power. An individual transformer or bank of transformers connected together comprises the load 130. The transformers may be three phase transformers for large industrial applications or single phase transformers used to provide electricity to a residential consumer.
Three types of power switching devices 110 that utility companies use in the power switching configuration 100 are fault interrupters, breakers and reclosers. Each power switching device 110 performs a preprogrammed response when a fault condition in the power distribution circuit 140 is detected by the controller 112. For example, the fault interrupter opens once and remains open when a fault condition is detected. The breaker opens after a fault, but attempts to close before remaining open if the fault continues to exist. A recloser opens and closes multiple times when a fault condition exists. By opening and closing multiple times, the recloser attempts to clear the fault. Should the fault condition continue to exist, the recloser opens and remains open until reset manually. The recloser enters a “lock out” state when this occurs.
A fault condition occurs when one phase of power becomes shorted to ground, phases become shorted to each other, or when lightning strikes the distribution circuit 140. When a fault condition occurs, large amounts of current flow through the power distribution circuit 140. The controller 112 monitors the voltage and current levels communicated to it by the power switching device 110. The power switching device 110 sends this information to the controller 112 through the bidirectional communications bus 114. When an abnormal current level is detected by the controller 112, the controller 112 signals the power switching device 110 to execute the preprogrammed response. Two examples of controllers 112 used with a power switching device 110 that include the present invention are the ICD (Intelligent Control Device) and the PCD (Programmable Control Device), manufactured by ABB Inc.
A cross sectional view of a typical power switching device 110 in the form of a prior art recloser 200 such as the OVR-1 Single Phase Recloser manufactured by ABB Inc. is illustrated in
Mounted around the H2 connector 214 is a power switching current transformer 236. As the AC current flows through the recloser 200, it causes a proportional electrical current to flow through the power switching current transformer 236. The two leads of the current transformer 236 are connected to the bidirectional communications bus 114 which in turn connects to the controller 112. The proportional current from the power switching current transformer 236 is sent to the controller 112 through the bidirectional communications bus 114.
As shown in
The H1212 and H2214 connectors protrude out of the housing 210 and are connected to distribution network 140 by power source wires and load wires (not shown) respectively. To facilitate the connection of the H1 connector 212 to the power source 120, the H1 connector 212 is manufactured with a threaded hole (not shown) at its protruding end. The power source wires are secured to the H1 connector 212 by a bolt inserted into the threaded hole and tightened. While not shown, it can be appreciated that top portions of the H1 connector 212 may have a parallel surface to allow the craftsperson to hold the H1 connector 212 in place with a wrench or other securing tool when tightening the bolt. Instead of two parallel sides as shown in
The core 301 and the protrusion 302 can be manufactured as a single piece and out of the same electrically conductive material such as copper or aluminum. Alternatively, the protrusion 302 may be a different type of electrically conductive metallic material and attached to the core 301. For example, an aluminum protrusion 302 may be welded or possibly bolted to a copper core 301.
One important aspect of this embodiment is the lack of sharp edges of the protrusion 302 and the core 301. The combination of the protrusion 302 with the core 301 provides the securing function that is absent in the prior art H1 connectors 212. The irregular shape of the connector 300 acts as an anchor to keep the connector 300 from rotating. The lack of sharp edges reduces the amount of stress the housing 210 experiences when the epoxy hardens. Excess stress during the curing process can lead to stress fractures which also degrade the structural integrity of the connector 300.
The C-shape protrusion 406 allows compressional forces applied to the top 408 of the connector 400 to be distributed away from base 402. By distributing the compressional force, the vacuum interrupter 230 attached to the base 402 is not subjected to the full brunt of the force. If the full compressional force were to be transmitted through a non C-shaped connector, the stationary contact 232 may become dislodged and the integrity of the vacuum interrupter 230 may be compromised.
In order to distribute the compressional force away from the vacuum interrupter 230, the connector 400 is designed to allow epoxy to flow into the gap 404 during the manufacturing process. Once the epoxy solidifies, it provides a buffering layer between the top 408 and base 402, which is able to absorb a portion of the compressional force.
The base 402 has a mounting hole 410 to allow easy connection to the vacuum interrupter 230. The vacuum interrupter 230 can be manufactured with a mounting bolt (not shown) that extends through the mounting hole 410 and is secured with a nut (not shown). The gap 404 allows manufacturing personnel assembling the recloser 200 easy access to the mounting bolt and nut during the assembly process.
Similar to the connector 300 of
It is to be understood that the foregoing description has been provided merely for the purpose of explanation and is in no way to be construed as limiting of the invention. Where the invention has been described with reference to embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Further, although the invention has been described herein with reference to particular structure, materials and/or embodiments, the invention is not intended to be limited to the particulars disclosed herein. Rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. Those skilled in the art, having the benefit of the teachings of this specification, may effect numerous modifications thereto and changes may be made without departing from the scope and spirit of the invention in its aspects.
This application claims the priority of U.S. provisional patent application Ser. No. 60/576,475 filed on Jun. 3, 2004, entitled “Embedded Pole Apparatus,” the contents of which are relied upon and incorporated herein by reference in their entirety, and the benefit of priority under 35 U.S.C. 119(e) is hereby claimed
| Number | Date | Country | |
|---|---|---|---|
| 60576475 | Jun 2004 | US |
