Patent Publication Number: US-2017358389-A1

Title: Transformer enclosure with improved cooling

Description:
FIELD OF THE INVENTION 
     This invention relates to transformers and more particularly to a transformer enclosure with improved cooling. 
     BACKGROUND 
     An electrical transformer converts electricity at one voltage to electricity at another voltage, either of higher or lower value. This voltage conversion is achieved using a coil assembly that includes a primary coil and a secondary coil in the transformer, each of which are wound on a ferromagnetic core and comprise a number of turns of an electrical conductor. The primary coil is connected to a source of voltage and the secondary coil is connected to a load. The coil assembly is mounted to a leg of the core, and the core includes first and second yokes connected by the leg. Certain transformers include multiple legs and a coil assembly on each leg. 
     For dry type transformers, such as those with coils for open windings, the core and coil assemblies are placed in an enclosure. In dry transformers, the high voltage conductor of the coil assembly is not embedded in resin. The resistance to the electric current by the metal wires of the transformer produces heat in the enclosure. The production of heat further increases the resistance to the current, and the overall efficiency of the transformer is reduced by the added heat unless the heat is removed from the enclosure. 
     Thus, some transformer enclosures include ventilation openings for circulation of air currents through the enclosure. However, restrictions and/or resistance to air flow through transformer enclosures can result in thermal build-up in the enclosure and increased inefficiencies in the transformer cooling process. Therefore, further improvements in transformer enclosures to provide improved cooling are needed. 
     SUMMARY 
     In accordance with the present disclosure, a transformer is provided that includes an enclosure configured to house a core along with a coil assembly mounted to the core. The enclosure includes a number of vertically extending sidewalls, at least one top wall connecting the sidewalls at or adjacent to a top end of the enclosure, and a bottom end opposite the top end. At least one of the sidewalls is joined to an access panel that is angled to extend below the top wall and between the bottom end of the enclosure and the at least one sidewall. A first ventilation opening is provided in the access panel and a second ventilation opening is provided in the at least one sidewall adjacent the top wall. 
     Since the first ventilation opening is provided in the angled access panel, air flow through the first ventilation opening and into the enclosure is improved due to less air flow resistance. The disclosed embodiments improve cooling and ventilation of transformers enclosures as compared to standard enclosures. The reduced heat build-up within the enclosure may reduce the size and material cost of the enclosed transformer. 
     This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view of one embodiment of a transformer enclosure. 
         FIG. 2  is a schematic elevational view of the transformer enclosure looking toward the left hand side of the perspective view of  FIG. 1 . 
         FIG. 3  is another schematic elevational view of the transformer enclosure looking toward a right hand side that is opposite the left hand side of the perspective view of  FIG. 1 . 
         FIG. 4  is a schematic elevational view of a side connecting the left hand and right hand sides of  FIGS. 2 and 3  with the wall panel(s) omitted to show structural supports. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring now to  FIG. 1 , there is shown a diagrammatic perspective view of a ventilated transformer enclosure  10  that can house, for example, a three phase, open wound dry transformer  100 , shown schematically in  FIG. 4 . In one embodiment, the transformer  100  comprises three coil assemblies  102  (one for each phase, only one shown in the end view of  FIG. 4 ) mounted to the core  104  and enclosed within enclosure  10 . The core  104  can be made of ferromagnetic metal, and is generally rectangular in shape with three spaced-apart legs (not shown) extending between first and second yokes  106 ,  108 . The coil assemblies  102  are mounted to and disposed around respective legs of the core  104 . 
     In one embodiment, the transformer  100  is a distribution transformer and has a kVA rating in a range of from about 112.5 kVA to about 15,000 kVA. The voltage of the high voltage coil is in a range of from about 600 V to about 35 kV and the voltage of the low voltage coil is in a range of from about 120 V to about 15 kV. However, other types of transformers, ratings and voltages are also contemplated and not precluded. Although the transformer  100  is shown and described as being a three phase transformer, it should be appreciated that the present invention is not limited to three phase transformers. For example, the present invention may be utilized in single phase and two phase transformers as well. 
     Enclosure  10  includes a plurality of vertically extending sidewalls, designated as first sidewall  12 , second sidewall  14 , third sidewall  16 , and fourth sidewall  18 , that collectively form an inner space  20  that houses transformer  100  as shown in  FIG. 4 . Vertically extending sidewalls  12 ,  14 ,  16 ,  18  extend in a vertical or near vertical orientation. The enclosure  10  extends between a top end  22  and an opposite bottom end  24 . At top end  22 , at least one top wall  26  extends over the inner space  22  and connects the plurality of vertically extending sidewalls  12 ,  14 ,  16 ,  18  at or adjacent the top end  22  of the enclosure  10 . In the illustrated embodiment, top wall  26  is shown as a single section, horizontally-oriented wall panel. Other embodiments contemplate that top wall  26  includes multiple sections, panels, and/or non-horizontal arrangements. In addition, while four vertically extending sidewalls  12 ,  14 ,  16 ,  18  are shown that each extend transversely to one another to define a square or rectangular horizontal shape in a plan view, more than four sidewalls can be provided to form rectangular or non-rectangular shapes. 
     Transformer enclosure  10  further includes a base  28  at the bottom end  24  of the enclosure  10 . Base  28  can be a skid, platform, rails or other suitable structure to support enclosure  10  and transformer  100 , such as on the ground, a concrete pad, a foundation, or on any other suitable structure or surface. Sidewalls  12 ,  14 ,  16 ,  18  are connected to base  28  by one or more columns or struts, as discussed further below. In addition, transformer  100  can be supported on base  28 . 
     Referring further to  FIGS. 2-4 , enclosure  10  further includes at least one first access panel  30  associated with first sidewall  12  and at least one second access panel  32  associated with a second sidewall  14  opposite first sidewall  12 . Each access panel  30 ,  32  extends in an angular orientation from and relative to the respective first or second sidewall  12 ,  14  toward base  28  so that each access panel  32  is directly vertically below the at least one top wall  26 . Each of the access panels  30 ,  32  includes at least one ventilation opening  34 ,  36 , respectively, to allow air inflow into enclosure  10 . In addition, each of the associated vertically extending first and second sidewalls  12 ,  14  includes at least one ventilation opening  38 ,  40  above the respective access panel ventilation openings  34 ,  36  to allow air outflow. Other embodiments contemplate multiple ventilation openings in the first and second sidewalls  12 ,  14  and/or in the respective access panels  30 ,  32 . 
     Opposite third and fourth vertically extending sidewalls  16 ,  18  each extend from base  28  to top wall  26  in a vertical or near-vertical orientation. Third and fourth sidewalls  16 ,  18  also extend between and connect each of the first and second sidewalls  12 ,  14  and the first and second access panels  30 ,  32 . The third and fourth sidewalls  16 ,  18  are identical and therefore will be described together with reference to third sidewall  16  in  FIG. 4 , it being understood the description of third sidewall  16  is applicable to fourth sidewall  18 . Furthermore, in  FIG. 4  the wall panels on third sidewall  16  are removed to better show the interior coil assembly  102 , the columns, and the struts. In  FIG. 1 , at least one wall panel  96  is shown that covers the respective third sidewall  16 , it being understood that fourth sidewall  18  can similarly include a wall panel. Wall panel  96  extends from top wall  26  to bottom end  24 , and from first sidewall  12  and first access panel  30  to second sidewall  14  and second access panel  32 . Other embodiments contemplated multiple wall panels one or both of sidewalls  16 ,  18 . 
     As shown in  FIG. 4 , third sidewall  16  includes, in the illustrated embodiment, a center column  42 , and first and second intermediate columns  44 ,  46  on opposite sides of center column  42 . The illustrated embodiment further includes first and second corner columns  48 ,  50  that are connected to base  28  with first and second angular corner struts  52 ,  54 . The corner struts  52 ,  54  extend along the respective access panels  30 ,  32 . Corner struts  52 ,  54  support corner columns  48 ,  50  on base  28 . Center column  42  and first and second intermediate columns  52 ,  54  are also supported directly one base  28 . 
     Referring back to  FIGS. 2-3 , there is shown in the illustrated embodiment a second access panel  56  extending from first sidewall  12  to base  28  that is angled to be directly vertically below the top wall  26  like first access panel  30 . The opposite sidewall  12  can also include a similar second access panel  58  as shown in  FIG. 3 . The second access panels  56 ,  58  extend from the bottom end  24  of the enclosure  10  to the respective first and second vertically extending sidewalls  12 ,  14 . Each of the first access panels  30 ,  32  and second access panels  56 ,  58  is in an angular orientation relative to the respective vertically extending sidewall  12 ,  14  and extends below top wall  26 . In addition, each of the second access panels  56 ,  58  includes a third ventilation opening  60 ,  62 , respectively. Furthermore, vertically extending sidewalls  12 ,  14  each include a respective fourth ventilation opening  64 ,  66  above respective ones of the angularly oriented third ventilation openings  60 ,  62 . 
     The first and second access panels  30 ,  56  associated with first sidewall  12  are positioned in side-by-side relation, and the first and second access panels  32 ,  58  associated with the second sidewall  14  are in side-by-side relation. In one embodiment, the enclosure  10  includes a height H 1  as shown in  FIG. 4  between top and bottom ends  22 ,  24  and access panels  30 ,  32 ,  56 ,  58  extend along a height H 2  of enclosure  10  that is around 20% of height H 1 . Other embodiments contemplate height H 2  ranging from 10% to 30% of H 1 , or any other suitable height H 2  that allows one or more ventilation openings to be provided directly vertically below top wall  26 . 
     In the illustrated embodiment, first sidewall  12  includes first and second vertically extending sidewall parts  65 ,  67  in side-by-side position extending from respective ones of the two access panels  30 ,  56  to the top wall  26 . The second ventilation opening  38  is provided in first sidewall part  65  and the fourth ventilation opening  64  is provided in second sidewall part  67 . 
     In the illustrated embodiment, second sidewall  14  includes third and fourth vertically extending sidewall parts  68 ,  70  in side-by-side position extending from respective ones of the two access panels  32 ,  58  to the top wall  26 . The second ventilation opening  40  is provided in third sidewall part  68  and the fourth ventilation opening  66  is provided in fourth sidewall part  70 . 
     In the illustrated embodiment, first sidewall  12  also includes a first intermediate column  72  between the first and second vertically extending sidewall parts  65 ,  67 . First sidewall  12  can further include a first intermediate strut  74  between the two access panels  30 ,  56 . The first intermediate strut  74  extends from the intermediate column  72  to the base  28 , and the first intermediate column  72  extends from the first intermediate strut  74  toward the top end  22  of the enclosure  10 . 
     In the illustrated embodiment, first sidewall  12  also includes a second intermediate column  76  between the first intermediate column  72  and the third sidewall  16 . A third intermediate column  78  is between the first intermediate column  72  and the opposite fourth sidewall  18 . In addition, a second intermediate strut  80  is between the first intermediate strut  74  and the first corner strut  52  at third sidewall  16 , the second intermediate strut  80  extending from the second intermediate column  76  to the base  28 . The second intermediate column  76  extends from the second intermediate strut  80  toward the top end  22  of the enclosure  10 . A third intermediate strut  82  is located between the first intermediate strut  74  and the third corner strut (opposite corner strut  52 ) at fourth sidewall  18 . The third intermediate strut  82  extends from the third intermediate column  78  to the base  28  of the enclosure  10 . The third intermediate column  78  extends from the third intermediate strut  82  toward the top end  22  of the enclosure  10 . 
     In the illustrated embodiment, second sidewall  14  may also include a fourth intermediate column  84  between the third and fourth vertically extending sidewall parts  68 ,  70 . There can further be provided a fourth intermediate strut  86  between the two access panels  32 ,  58 . The fourth intermediate strut  86  extends from the fourth intermediate column  84  to the base  28 , and the fourth intermediate column  84  extends from the fourth intermediate strut  86  toward the top end  22  of the enclosure  10 . 
     In the illustrated embodiment, second sidewall  14  also includes a fifth intermediate column  88  between the fourth intermediate column  84  and the third sidewall  16 . A sixth intermediate column  90  is between the fourth intermediate column  84  and fourth sidewall  18 . In addition, a fifth intermediate strut  92  is between the fourth intermediate strut  86  and the second corner strut  54  at third sidewall  16 , and the fifth intermediate strut  92  extends from the fifth intermediate column  88  to the base  28 . The fourth intermediate column  84  extends from the fourth intermediate strut  86  toward the top end  22  of the enclosure  10 . A sixth intermediate strut  94  is between the fourth intermediate strut  86  and the fourth corner strut (opposite corner strut  54 ) at fourth sidewall  18 . The sixth intermediate strut  94  extends from the sixth intermediate column  90  to the base  28  of the enclosure  10 . The sixth intermediate column  90  extends from the sixth intermediate strut  94  toward the top end  22  of the enclosure  10 . 
     Other embodiments contemplate other arrangements for the struts and columns that differ from those described herein. In still other embodiments, all or a portion of the struts and columns can be omitted, or additional struts and/or columns can be provided. Furthermore, although not specifically shown, top end  22  can include one or more beams to support top wall  26 . 
     The angularly oriented struts  52 ,  74 ,  80 ,  82 ,  54 ,  86 ,  92 ,  94  and access panels  30 ,  56 ,  32 ,  58  disclosed herein can extend at an angle A toward the inner space  20  from an extension of the respective adjacent vertically extending sidewall, as shown in  FIG. 4  with respect to first sidewall  12 . Angle A can be any suitable angle to facilitate air up-flow into and through the ventilation opening(s) of the respective access panel(s). In one embodiment, angle A is about 45 degrees. In other embodiments, angle A can be selected to be angle in the range from 30 degrees to 60 degrees. 
     In one embodiment, the enclosure  10  includes a first width W 1  between first and second sidewalls  12 ,  14  at top end  22  and a second, smaller width W 2  at bottom end  24  between the bottom ends of the access panels  30 ,  32 ,  54 ,  56 . The access panels  30 ,  32  and  54 ,  56  are angled to connect the first width W 1  to the second width W 2 . In this arrangement, the access panels  30 ,  32  extend inwardly from the respective sidewall  12 ,  14  and below top wall  26 . In the illustrated embodiment, access panels  30 ,  32  each extend across a width W 3  that is about 20% of the overall width W 1 . Other embodiments contemplate any other suitable width W 3 . 
     Various aspects of the present disclosure are contemplated. In one aspect, a transformer includes an enclosure with a plurality of vertically extending sidewalls forming an inner space, and the enclosure extends between a top end and a bottom end. At least one top wall connects the plurality of vertically extending sidewalls at or adjacent the top end of the enclosure, and a base is provided at the bottom end of the enclosure. At least one access panel is provided in an angular orientation relative to adjacent ones of the plurality of vertically extending sidewalls to extend below the at least one top wall. The at least one access panel extends in the angular orientation from the bottom end to a first one of the vertically extending sidewalls. The at least one access panel includes at least one first ventilation opening and at least one second ventilation opening is provided through the enclosure above the at least one first ventilation opening. The plurality of vertically extending sidewalls extend from the top wall to either the at least one access panel or the bottom end of the enclosure. 
     In one embodiment, the transformer includes a second access panel angled below the at least one top wall. The second access panel extends from the bottom end of the enclosure to a second one of the vertically extending sidewalls that is opposite the first one of the vertically extending sidewalls. The second access panel is in an angular orientation relative to the second one of the vertically extending sidewalls. In a refinement of this embodiment, the second access panel includes a third ventilation opening and the enclosure includes a fourth ventilation opening in the second one of the plurality of vertically extending sidewalls that is above the third ventilation opening. 
     In yet another embodiment, the at least one access panel includes two access panels in side-by-side position, and the at least one first ventilation opening is provided in one of the two access panels and a third ventilation opening is provided in the other of the two access panels. In a refinement of this embodiment, the first one of the vertically extending sidewalls includes first and second vertically extending sidewall parts in side-by-side position extending from respective ones of the two access panels to the top wall, and the at least one second ventilation opening is provided in one of the first and second vertically extending sidewall parts and a fourth ventilation opening is provided in the other of the first and second vertically extending sidewall parts. In a further refinement, the enclosure includes a first intermediate column between the first and second vertically extending sidewall parts and a first intermediate strut between the two access panels. The first intermediate strut extends from the intermediate column to the base, and the first intermediate column extends from the first intermediate strut toward the top end of the enclosure. 
     In yet a further refinement of the above embodiments, the enclosure includes a first corner column and a second corner column at opposite sides of the first one of the vertically extending sidewalls, and a first corner strut and a second corner strut extending from respective one of the first and second corner columns to the base of the enclosure. The first and second corner struts parallel the two access panels, and the first and second corner columns extend from respective ones of the first and second corner struts toward the top wall of the enclosure. In still a further refinement, the enclosure includes a second intermediate column between the first intermediate column and the first corner column, a third intermediate column between the first intermediate column and the second corner column, a second intermediate strut between the first intermediate strut and the first corner strut, and a third intermediate strut between the first intermediate strut and the second corner strut. The second intermediate strut extends from the second intermediate column to the base, and the second intermediate column extends from the second intermediate strut toward the top end of the enclosure. The third intermediate strut extends from the third intermediate column to the base of the enclosure, and the third intermediate column extends from the third intermediate strut toward the top end of the enclosure. 
     In one embodiment, the plurality of vertically extending sidewalls includes a second one of the vertically extending sidewalls that is opposite the first one of the vertically extending sidewalls. The plurality of vertically extending sidewalls further include opposite third and fourth ones of the vertically extending sidewalls that extend transversely to and connect the first and second ones of the vertically extending sidewalls. The enclosure includes at least one second access panel below the at least one top wall that extends from the base of the enclosure to the second one of the vertically extending sidewalls in an angular orientation relative to the second one of the vertically extending sidewalls. The at least one second access panel includes at least one third ventilation opening and at least one fourth ventilation opening is provided through the second one of the vertically extending sidewalls above the at least one third ventilation opening. In a refinement of this embodiment, the third and fourth ones of the vertically extending sidewalls each include at least one wall panel extending from the top wall to the bottom end of the enclosure and from the first one of the vertically extending sidewalls and first access panel to the second one of the vertically extending sidewalls and second access panel. 
     In one embodiment, the first one of the vertically extending sidewalls defines a first plane and the at least one access panel forms an angle from the first plane toward the inner space. T the angle ranges from 30 degrees to 60 degrees. In a refinement of this embodiment, the angle is 45 degrees. In another embodiment, the plurality of vertically extending sidewalls forms a rectangular shape. 
     In another embodiment, the transformer includes a core and a coil assembly mounted to the core in the inner space of the enclosure. In yet another embodiment, the at least one access panel extends along about 20% of an overall height of the enclosure and across about 20% of an overall width of the enclosure. 
     Another aspect is directed to an enclosure for a transformer. The enclosure includes a plurality of vertically extending sidewalls forming an inner space for receiving a transformer coil assembly. At least one top wall connects the plurality of vertically extending sidewalls above the inner space. At least one access panel is in an angular orientation relative to a first one of the vertically extending sidewalls to extend from the first one of the vertically extending sidewalls below the at least one top wall. The at least one access panel includes at least one first ventilation opening and at least one second ventilation opening is provided in the first one of the vertically extending sidewalls above the at least one first ventilation opening. The at least one access panel extends from the first one of the vertically extending sidewalls to a bottom end of the enclosure. 
     In one embodiment, a base is opposite the at least one top wall and the at least one access panel extends from the first one of the vertically extending sidewalls toward the base. 
     In another embodiment, the enclosure includes a second access panel below the at least one top wall. The second access panel extends from the base to a second one of the vertically extending sidewalls that is opposite the first one of the vertically extending sidewalls. The second access panel is in an angular orientation relative to the second one of the vertically extending sidewalls. In a refinement of this embodiment, the second access panel includes a third ventilation opening and the enclosure includes a fourth ventilation opening in the second one of the vertically extending sidewalls that is above the third ventilation opening. 
     In another embodiment, the first one of the vertically extending sidewalls defines a first plane and the at least one access panel forms an angle from the first plane toward the inner space, wherein the angle ranges from 30 degrees to 60 degrees. In a refinement of this embodiment, the angle is 45 degrees. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the certain embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary. Unless specified or limited otherwise, the terms “engaged,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect engagements, connections, supports, and couplings.