Patent Publication Number: US-2023148054-A1

Title: Support bracket for transformer switch utilizing existing transformer connection points

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority from the U.S. Provisional Application No. 63/278,219, filed on Nov. 11, 2021, the disclosure of which is hereby expressly incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     Field 
     The present disclosure relates generally to a support bracket assembly for supporting a pair of switching devices provided within a transformer enclosure and, more particularly, to a support bracket assembly for supporting a pair of bushing well interrupter devices provided within a transformer enclosure for a transformer used in an underground residential power distribution network. 
     Discussion of the Related Art 
     An electrical power distribution network, often referred to as an electrical grid, typically includes power generation plants each having 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 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 three-phase feeders including three single-phase feeder lines that carry the same current but are 120° apart in phase. 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 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 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 its power distribution network, many utility companies employ 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 fail 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 failed 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 failure 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. If the bushing well interrupter devices can be installed without modifying the existing transformers, it will be that much more appealing to the utility. However, the addition of the bushing well interrupter devices, which can be relatively heavy, puts added stress on the transformer bushings due to the added weight and off-center moments, which may cause the bushings to prematurely wear out and have to be replaced. Therefore, a support bracket for supporting the bushing well interrupter devices may be necessary. Such a support bracket must be flexible enough to connect to a variety of transformers that have been manufactured by different companies with limited labor and, at the same time, the support bracket must provide enough stiffness to each bushing well interrupter device so as to not allow any additional stresses at the transformer bushing well than are currently present in the existing transformers. 
     SUMMARY 
     The following discussion discloses and describes a support bracket assembly for supporting a pair of bushing well interrupter devices provided within a transformer enclosure that encloses a transformer. The support bracket assembly includes a mounting bracket assembly rigidly secured to the enclosure and including a plurality of mounting bosses. The support bracket assembly further includes a first support bracket secured to one of the interrupter devices, a second support bracket secured to the other interrupter device, a third support bracket secured to the first support bracket, where the third support bracket includes a plurality of mounting bosses, and a fourth support bracket secured to the second support bracket, where the fourth support bracket includes a plurality of mounting bosses. The support bracket assembly also includes a first adjustable link secured to one of the mounting bosses on the mounting assembly and one of the mounting bosses on the third support bracket, a second adjustable link secured to another one of the mounting bosses on the mounting assembly and one of the mounting bosses on the fourth support bracket, and a third adjustable link secured to another one of the mounting bosses on the third support bracket and another one of the mounting bosses on the fourth support bracket, where the first, second and third adjustable links form a triangular configuration. 
     Additional features of the disclosure will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an isometric view of a pad mounted transformer employed in an underground residential loop circuit and including a pair of bushing well interrupter devices; 
         FIG.  2    is a front view of the transformer shown in  FIG.  1   ; 
         FIG.  3    is a front view of the transformer shown in  FIG.  1    with the bushing well interrupter devices and other components removed; 
         FIG.  4    is a broken-away front view of the transformer illustrating a support bracket assembly for supporting the bushing well interrupter devices to the transformer enclosure; 
         FIG.  5    is a broken-away side view of the transformer illustrating the support bracket assembly; 
         FIG.  6    is a broken-away view of the transformer illustrating the support bracket assembly in a partially assembled state; 
         FIG.  7    is a broken-away view of the transformer illustrating the support bracket assembly in a further partially assembled state; 
         FIG.  8    is a broken-away view of the transformer illustrating the support assembly in a further partially assembled state; 
         FIG.  9    is a broken-away view of the transformer illustrating the support bracket assembly in a further partially assembled state; 
         FIG.  10    is an isometric view of a parking stand support bracket that is part of the support bracket assembly; 
         FIG.  11    is an isometric view of a parking stand anchor bracket that is part of the support bracket assembly; and 
         FIG.  12    is a front view of an adjustable link that is part of the support bracket assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The following discussion of the embodiments of the disclosure directed to a support bracket assembly for supporting a pair of bushing well interrupter devices 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 support bracket assembly discussed herein has particular application for use with transformers employed in underground residential loop circuits. However, the support bracket assembly may have other applications. 
       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 device  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 device  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 devices  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 devices  22  and  32  are mirror images of each other to accommodate spacing for the existing features on the transformer  10 . The devices  22  and  32  each include an outer enclosure  40 , a load-break interface  42 , a transformer interface  46  and a manual handle  48 . 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 . Distribution 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. 
     As will be discussed in detail below, a support bracket assembly  76  (see  FIGS.  4  and  5   ) is added to the transformer  10  to support the bushing well interrupter devices  22  and  32  on the panel  16 . To begin this discussion,  FIG.  3    shows the transformer  10  with the bushing well interrupter devices  22  and  32  and other components removed, which illustrates a parking stand  78  that is welded to the panel  16  between the bushing connectors  20  and  30 , where the parking stand  78  includes a raised panel  80  having a cut-out section  82 . The parking stand  78  is an existing fixture that allows one of the elbow connectors  26  or  36  to be supported thereto when it is disconnected from the bushing connector  20  or  30  to provide a break in the loop circuit prior to the bushing well interrupter devices  22  and  32  being employed in the transformer  10 , which will be used to support the bracket assembly  76  referred to above. More particularly, when the elbow connector  26  or  36  is removed from the bushing  20  or  30 , it is inserted in the cut-out section  82  so that part of it locks between the panels  16  and  80 . 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  including providing access to the parking stand  78 . 
       FIG.  4    is a broken-away front view and  FIG.  5    is a broken-away side view of the transformer  10  illustrating the support bracket assembly  76  and  FIGS.  6 - 9    are broken-away views of the transformer  10  illustrating the support bracket assembly  76  is various stages of assembly. Before the bushing well interrupter devices  22  and  32  are secured to the connector bushings  20  and  30 , respectively, a support bracket  84  having opposing flanges  86  is bolted to the interface of the device  22  and a support bracket  88  having opposing flanges  90  is bolted to the interface of the device  32 . The assembly  76  is secured to the parking stand  78  using a parking stand bracket  92  and an anchor bracket  94 , where  FIG.  10    shows the parking stand bracket  92  separated from the assembly  76  and  FIG.  11    shows the anchor bracket  94  positioned relative to the parking stand  78 . The bracket  92  includes a top wall  102  having wings  104  and  106 , a cut-out section  108  and an oval window  110 , side walls  112  and  114  and a lower flange  116  having a pair of J-shaped slots  118  and  120  that can be seen through the window  110 . The bracket  92  has the general configuration of the parking stand  78  to allow it to be used as a parking stand for the elbow connectors  26  and  36  when the parking stand  78  is being used to secure the bracket assembly  76 . The anchor bracket  94  includes a base portion  122  to which are secured raised bolts  124  and  126  and an anchor portion  128  to which are secured tapered bosses  130  and  132 . The anchor portion  122  is slid between the panels  16  and  80  and the bolts  124  and  126  are extended through the cut-out section  82 . The bracket  92  is positioned so that the bolts  124  and  126  are inserted and locked in the J-shaped slots  118  and  120 , respectively. The bolts  124  and  126  are then tightened to secure the brackets  92  and  94  to the parking stand  78 . 
     The assembly  76  also includes a support bracket  140  having an L-shaped body  142  with a short portion  144  and a long portion  146 . A tab  148  extends from the long portion  146 , a tapered boss  150  including a threaded opening extends from the side of the long portion  146  and a tapered boss  152  including a threaded opening extends from the short portion  144 . A threaded rod  154  is threaded into the tab  148 , where the rod  154  includes a support  156  mounted thereto opposite to the tab  148 . The short portion  144  is bolted to the flanges  90  by bolts  158  and the threaded rod  154  is adjusted by threading through the tab  148  so that the support  156  pushes against the panel  16  with the desired force to prevent downward sagging of the device  32 . The assembly  76  also includes a support bracket  170  having a T-shaped body  172 . One end of the body  172  includes tapered bosses  174  and  176  having threaded openings extending therefrom and an opposite end of the body portion  172  is bolted to the flanges  86  by bolts  178 . 
     The assembly  76  also includes an adjustable link  180  having a cylindrical portion  182  and a threaded portion  184  threaded into the cylindrical portion  182 .  FIG.  12    is a front view of the link  180  separated from the bracket assembly  76 . The cylindrical portion  182  includes a ball joint  186  at an end opposite to the threaded portion  184 , where the ball joint  186  includes a ring  188  and a ball  190  having an opening  192  rotatably mounted within the ring  188 . The threaded portion  184  includes a ball joint  194  at an end opposite to the cylindrical portion  182 , where the ball joint  194  includes a ring  196  and a ball  198  having an opening  200  rotatably mounted within the ring  196 . The ball  190  is slid onto the boss  130  and secured thereto by a bolt  202  threaded into the opening  192 . The threaded portion  184  is threaded so that the ball joint  194  aligns with the boss  150 . The ball  198  is slid onto the boss  150  and secured thereto by a bolt  204  threaded into the opening  200 . 
     The assembly  76  also includes an adjustable link  210  having a cylindrical portion  212  and a threaded portion  214  threaded into the cylindrical portion  212 , where the link  210  is identical to the link  180 . The cylindrical portion  212  includes a ball joint  216  at an end opposite to the threaded portion  214  and the threaded portion  214  includes a ball joint  218  opposite to the cylindrical portion  212 . The ball joint  216  is mounted to the boss  132  and secured thereto by a bolt  220  threaded into the opening of the boss  132 . The threaded portion  214  is threaded so that the ball joint  218  aligns with the boss  176 . The threaded portion is then retracted a predetermined amount and the device  22  is lifted against sagging so that the ball joint  218  again aligns with the boss  176 . The ball joint  218  is then mounted to the boss  176  and secured thereto by a bolt  222  threaded into the opening of the boss  176 . 
     The assembly  76  also includes an adjustable link  230  having a cylindrical portion  232  and a threaded portion  234  threaded into the cylindrical portion  232 , where the link  230  is identical to the link  180 . The cylindrical portion  232  includes a ball joint  236  at an end opposite to the threaded portion  234  and the threaded portion  234  includes a ball joint  238  opposite to the cylindrical portion  232 . The ball joint  236  is mounted to the boss  152  and secured thereto by a bolt  240  threaded into the opening of the boss  152 . The threaded portion  234  is threaded so that the ball joint  238  aligns with the boss  174 . The ball joint  238  is then mounted to the boss  174  and secured thereto by a bolt  242  threaded into the opening of the boss  174 . Thus, the combination of the adjustable links  180 ,  210  and  230  form a triangular configuration. 
     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.