Patent Application
20230014710
The present disclosure relates generally to a mounting bracket for securing a control unit that controls a bushing well interrupter device provided within a transformer enclosure.
An electrical power distribution network, often referred to as an electrical grid, typically includes a number of power generation plants each having a number of power generators, such as gas turbines, nuclear reactors, coal-fired generators, hydro-electric dams, etc. The power plants provide power at a variety of medium voltages that are then stepped up by transformers to a high voltage AC signal to be connected to high voltage transmission lines that deliver electrical power to a number of substations typically located within a community, where the voltage is stepped down to a medium voltage for distribution. The substations provide the medium voltage power to a number of three-phase feeders including three single-phase feeder lines that carry the same current, but are 120o apart in phase. A number of three-phase and single phase lateral lines are tapped off of the feeder that provide the medium voltage to various distribution transformers, where the voltage is stepped down to a low voltage and is provided to a number of loads, such as homes, businesses, etc.
Periodically, faults occur in the distribution network as a result of various things, such as animals touching the lines, lightning strikes, tree branches falling on the lines, vehicle collisions with utility poles, etc. Faults may create a short-circuit that increases the load on the network, which may cause the current flow from the substation to significantly increase, for example, many times above the normal current, along the fault path. This amount of current causes the electrical lines to significantly heat up and possibly melt, and also could cause mechanical damage to various components in the substation and in the network. Power distribution networks of the type referred to above often include a number of switching devices, breakers, reclosers, interrupters, etc. that control the flow of power throughout the network, and may be used to isolate faults within a faulted section of the network.
As part of their power distribution network, many utility companies employ a number of underground single-phase lateral circuits that feed residential and commercial customers. Often times these circuits are configured in a loop and fed from both ends, where an open location, typically at a transformer, is used in the circuit to isolate the two power sources. Although providing underground power cables protects circuits from faults created by things like storms and vegetation growth, underground cables still may break or otherwise be disrupted as a result of corrosion and other things.
For a residential loop circuit of the type referred to above having two power sources, it is usually possible to reconfigure the open location in the circuit so that loads that are affected by a disrupted cable are fed by the other source and service to all of the loads is maintained. However, known processes for identifying the location of a cable disruption and the subsequent reconfiguration of the open location often result in long power restoration times because workers are required to physically go to the transformers to test for power and then reconfigure the transformers to change the open location. It has been proposed to provide bushing well interrupter devices in the existing transformers for these types of loop circuits that provide automatic protection, isolation and restoration of underground residential cable loops and methods to switch cable segments without handling cable elbows.
The following discussion discloses and describes a mounting bracket for securing a control unit that controls a bushing well interrupter device provided within a transformer enclosure associated with an underground loop circuit. The mounting bracket includes a support portion configured to hold the control unit and a mounting portion coupled to the support portion, where the mounting portion includes a hook portion configured to hook onto one terminal in the enclosure and a notch portion configured to rest against another terminal in the enclosure.
Additional features of the disclosure will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.
The following discussion of the embodiments of the disclosure directed to a mounting bracket for securing a control unit that controls a bushing well interrupter device provided within a transformer enclosure is merely exemplary in nature, and is in no way intended to limit the invention or its applications or uses. For example, the mounting brackets discussed herein have particular application for use with transformers employed in underground residential loop circuits. However, the mounting brackets may have other applications.
The bushing well interrupter devices 22 and 32 are an added feature to existing transformers of the type shown and described above already operating in the field, and are configured to be usable in the space provided in the enclosure 14. This configuration includes controlling the devices 22 and 32 by a common control unit 70, where the control unit 70 is powered by 120 V ac from the secondary coil and is connected to the bushing well interrupter devices 22 and 32 by control lines 72 connected to terminals 74 on the control unit 70. In order to allow the devices 22 and 32 to be employed in existing pad mounted transformers of the type described herein, the control unit 70 needs to be easily mounted to the existing structure. This disclosure proposes a mounting bracket 78 that is hung from the connector 50 adjacent to the bushing 52 for this purpose, where the distance between and the location of the bushings 52 and 56 in all of the transformers of this type are set by industry standards. The mounting bracket 78 is made of an electrically insulating material, such as a suitable plastic, to provide electrical isolation between the connectors 50, 54 and 58 and the control unit 70.
The bracket 78 offers one configuration of a device for mounting a control unit to the existing structure of the transformer 10. Other configurations may be equally applicable.
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.
This application claims the benefit of priority from the United States Provisional Application No. 63/220,291, filed on Jul. 9, 2021, the disclosure of which is hereby expressly incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63220291 | Jul 2021 | US |
