STRUCTURAL ARRANGEMENT FOR ATTACHMENT OF
CONDUCTOR WINDING PACKAGES IN AIR CORE REACTOR
[0001] BACKGROUND
[0002] Disclosed embodiments relate generally to the field of electrical apparatuses, and, more particularly, to air core reactors.
[0003] BRIEF DESCRIPTION
[0004] A disclosed embodiment is directed to an air core reactor including a first cylindrical winding package positioned to extend along a central axis from a first reactor end to a second reactor end and a second cylindrical winding package positioned radially inward of the first cylindrical winding package and positioned to extend along the central axis from the first reactor end to the second reactor end. A spider arm extends in a direction away from the central axis to a spider end and is coupled to the first cylindrical winding package and the second cylindrical winding package. An attachment flange includes an inner portion and an outer portion. The inner portion is coupled to the spider end. A first inner spacer assembly is positioned between the first cylindrical winding package and the second cylindrical winding package to maintain a first gap between the first cylindrical winding package and the second cylindrical winding package. The first inner spacer assembly has a first end coupled to the spider arm. A first outer spacer assembly is positioned between the first cylindrical winding package and the second cylindrical winding package. The first outer spacer assembly has a first end coupled to the outer portion of the attachment flange.
[0005] Another disclosed embodiment is directed to an air core reactor including a first cylindrical winding package positioned to extend along a central axis from a first reactor end to a second reactor end and a second cylindrical winding package positioned radially inward of the first cylindrical winding package and positioned to extend along the central axis from the first reactor end to the second reactor end. A spider arm extends in a direction away from the central axis to a spider end and is coupled to the first cylindrical winding package and the second cylindrical winding package. An attachment flange includes an inner portion and an outer portion. The inner portion is coupled to the spider end. A first inner spacer assembly is positioned between the first cylindrical winding package and the second cylindrical winding package to maintain a first gap between the first cylindrical winding package and the second cylindrical winding package. The first inner spacer assembly has a first end coupled to the spider arm. A first outer spacer assembly is positioned between the first cylindrical winding package and the second cylindrical winding package. The first outer spacer assembly has a first end coupled to the outer portion of the attachment flange. A third cylindrical winding package is positioned radially inward of the second cylindrical winding package and is positioned to extend along the central axis from the first reactor end to the second reactor end. A second inner spacer assembly is positioned between the second cylindrical winding package and the third cylindrical winding package to maintain a second gap therebetween. The second inner spacer assembly has a first end coupled to the spider arm. A second outer spacer assembly is positioned between the second cylindrical winding package and the third cylindrical winding package. The second outer spacer assembly has a first end coupled to the outer portion of the attachment flange.
[0006] BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. l is a fragmentary, cut-away view of an electrical apparatus, such as a dry-type air core reactor, that can benefit from disclosed structural arrangements for attaching conductor winding packages in the air core reactor.
[0008] FIG. 2 is an isometric, showing a generally fragmentary, front view of the winding packages and further showing an exploded view of an attachment flange prior to being assembled with a spider arm and respective spacer assemblies.
[0009] FIG. 3 shows the attachment flange illustrated in FIG. 2 when mechanically connected to the spider arm and the respective spacer assemblies.
[0010] FIG. 4 is an isometric, showing side and bottom views of portions of the winding packages and the attachment flange connected to the spider arm and the respective spacer assemblies.
[0011] FIG. 5 is a fragmentary, side view of the winding packages and respective attachment flanges respectively connected to opposite axial ends of the respective spacer assemblies.
[0012] FIG. 6 is a fragmentary, front view of the winding packages and the respective attachment flanges respectively connected to upper and lower spider arms and the respective spacer assemblies.
[0013] DETAILED DESCRIPTION
[0014] FIG. l is a fragmentary, cut-away view of an electrical apparatus, such as an air core reactor 10, that can benefit from disclosed embodiments described in greater detail below. Disclosed embodiments involve an improved structural arrangement for attaching cylindrical winding packages in the air core reactor. The terms air core reactor, air core inductor and air core coil are often used interchangeably by those skilled in the art and refer to inductors that involve an air core in lieu of a magnetic core made of a ferromagnetic material. An inductor (reactor, or coil) is a passive electrical component that may be used to store energy available in an electromagnetic field when electric current flows through the inductor.
[0015] In the following detailed description, various specific details are set forth in order to provide a thorough understanding of such embodiments. However, those skilled in the art will understand that disclosed embodiments may be practiced without these specific details that the aspects of the present invention are not limited to the disclosed embodiments, and that aspects of the present invention may be practiced in a variety of alternative embodiments. In other instances, methods, procedures, and components, which would be well- understood by one skilled in the art have not been described in detail to avoid unnecessary and burdensome explanation.
[0016] Furthermore, various operations may be described as multiple discrete steps performed in a manner that is helpful for understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations need be performed in the order they are presented, nor that they are even order dependent, unless otherwise indicated. Moreover, repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may.
[0017] It is noted that disclosed embodiments need not be construed as mutually exclusive embodiments, since aspects of such disclosed embodiments may be appropriately combined by one skilled in the art depending on the needs of a given application.
[0018] Air core reactor 10 includes one or more electrical devices, such as a plurality of radially-concentric, spaced-apart cylindrical winding packages 12 positioned about a central axis 13 that extends from a first reactor end 20 to a second reactor end 22. The cylindrical winding packages 12 may define a centrally-disposed hollow cavity 14. It will be appreciated that air core reactor designs may include fewer or substantially more winding packages than shown in FIG. 1 (e.g., ranging from one winding package to twenty or more winding packages). For simplicity of illustration, FIG. 1 illustrates just three winding packages labelled 12a, 12b, 12c.
[0019] Without limitation, cylindrical winding packages 12 may be positioned between an upper spider unit 15 and a lower spider unit 17, which, in certain embodiments, may function as terminals for connecting power lines and/or for interconnecting the cylindrical windings in a desired electrical configuration, such as a parallel circuit arrangement. It will be appreciated that the winding packages of the reactor are rigidly held between upper spider unit 15 and lower spider unit 17 by appropriate means, such as, without limitation, non- conductive materials, which may include precured composite members or uncured composite members (that are hardened when the reactor is cured). The spider units may constitute structural members that facilitate lifting and/or fastening to the mounting system of a given reactor to other reactors, or both. Cylindrical winding packages 12a, 12b, 12c may be radially separated from one another by a plurality of circumferentially spaced-apart spacers 19, which may be positioned to have a vertical orientation extending in a direction parallel to axis 13.
[0020] The present inventors have recognized that the structural strength of certain known mounting arrangements for the cylindrical winding packages in air core reactors may be limited by the structural capability of a bolted connection between the spacers and the spider units. For example, mechanical loads can develop during operation of the air core reactor and these loads can result in undesirable bending moments being formed and applied to the bolted connection. These bending moments, if left unrestrained, as is generally the case in such known mounting arrangements, can potentially affect the reliability and durability of the bolted connection between the spacers and the spider units.
[0021] At least in view of the foregoing recognition, disclosed embodiments make use of spacer assemblies appropriately arranged to counterbalance such moments and therefore improve the structural capability of the mechanical connection between the spacers and the spider units. Disclosed embodiments are also believed effective in resisting shear loads that may develop during operation of the air core reactor. Without limitation, spacer assemblies used in disclosed embodiments may be realized by way of appropriate adaptation of duct sticks generally used to facilitate convection cooling in the air core reactor.
[0022] FIG. 2 is an isometric, showing a generally front, fragmentary view of winding packages 12a, 12b, 12c and further showing an exploded view of an attachment flange 100 prior to being assembled with a spider arm 102 and respective spacer assemblies 104. FIG. 3 shows the attachment flange 100 when mechanically connected to the spider arm and the respective spacer assemblies 104. Without limitation, in the illustrated embodiment, the attachment flange 100 is coupled to spider arm 102, which may be part of lower spider unit 17 (FIG. 1). It will be appreciated that in certain applications a further attachment flange could be optionally coupled to a second spider arm that may be part of upper spider unit 15 (FIG. 1).
[0023] In one non-limiting embodiment, spider arm 102 extends in a direction away from central axis 13 to a spider end 106 and may be coupled to first winding package 12a and second winding package 12b. Although in FIG 1, the arms of spider units 15, 17 are illustrated as extending from central axis 13, it will be appreciated that in certain embodiments, the spider arms may be truncated. That is, the spider arms need not extend from central axis 13 but from a point located between central axis 13 and spider end 106.
[0024] In one non-limiting embodiment, attachment flange 100 includes an inner portion 108 and outer portions 110. As may be appreciated in FIGs. 3 and 4, the inner portion 108 of attachment flange 100 may be coupled proximate to spider end 106. It will be appreciated that for winding packages positioned radially closer to central axis 13, then the inner portion 108 of a respective attachment flange would be coupled to a location of spider arm 102, which is closer to central axis 13.
[0025] In one non-limiting embodiment, as shown in FIGs 2-4, a first inner spacer assembly 104a' is positioned between first winding package 12a and second winding package 12b to maintain a first gap between winding packages 12a, 12b. First inner spacer assembly 104a’ may have a first end 112' coupled to spider arm 102.
[0026] In one non-limiting embodiment, as shown in FIGs 2-5, a first outer spacer assembly 104b' is positioned between first winding package 12a and second winding package 12b. First outer spacer assembly 104b' has a first end 114' coupled to outer portions 110 of attachment flange 100.
[0027] In one non-limiting embodiment, a third winding package 12c may be positioned radially inward of second winding package 12b and may be positioned to extend along the central axis 13 from the first reactor end to the second reactor end. It will be appreciated that winding packages 12a, 12b, 12c need not be sequentially concentrically positioned adjacent to one another. As shown in FIGs 2-3, a second inner spacer assembly 104a" is positioned between second winding package 12b and third winding package 12c to maintain a second gap between second winding package 12b and third winding package 12c. Second inner spacer assembly 104a" has a first end 112" coupled to spider arm 102.
[0028] In one non-limiting embodiment, as shown in FIGs 2-5, a second outer spacer assembly 104b" is positioned between second winding package 12b and third winding package 12c. Second outer spacer assembly 104b" has a first end 114" coupled to outer portions 110 of attachment flange 100.
[0029] In one non-limiting embodiment, as shown in FIGs 2-4, a first isolator block 120' is positioned between spider arm 102 and first winding package 12a and a second isolator block 120" is positioned between spider arm 102 and second winding package 12b. Without limitation, the first and second isolator blocks 120 are electrical insulators. That is, made of a material having electrical insulating properties.
[0030] In one non-limiting embodiment, spider arm 102 includes a planar portion having a height (schematically represented by line h in FIG. 2) that extends parallel to the central axis 13 to define a first edge and a second edge, and a width (schematically represented by line w in FIG. 2) that extends in a direction normal to the central axis to define an edge width. In one nonlimiting embodiment, attachment flange 100 includes a first channel portion 130' and a second channel portion 130" fixedly attached to the first channel portion to define an inner slot 132 having a width sized to receive the edge width of the planar portion of spider arm 102.
[0031] In one non-limiting embodiment, as shown in FIG. 2, the outer portions 110 of attachment flange 100 include an outermost surface 134' of first channel portion 130' and an outermost surface 134"of the second channel portion 130" and the inner portion 108 of attachment flange 100 includes an inner most surface 136' of the first channel portion 130' and an innermost surface 136" of the second channel portion 130".
[0032] In one non-limiting embodiment, the first outer spacer assembly 104b' includes a first spacer and a second spacer separate from the first spacer. For example, the first spacer of the first outer spacer assembly 104b' may be connected to the outermost surface 134' of first channel portion 130' and the second spacer of the first outer spacer assembly 104b' may be connected to the outermost surface 134"of the second channel portion 130".
[0033] In one non-limiting embodiment, respective fasteners 140', such as without limitation may involve nuts and bolts, may be used to affix the first spacer of the first outer spacer assembly 104b' to the outermost surface 134' of first channel portion 130' and to affix the second spacer of the first outer spacer assembly 104b' to the outermost surface 134" of the second channel portion 130". For the sake of simplicity of illustration, fasteners are shown in connection with disclosed embodiments; it will be appreciated, however, that it is possible to use an alternative modality or combination of modalities to transfer compression and tensile loads, such as could include a geometric bearing feature (e.g., effective to transfer compression) and an adhesive (e.g., effective to transfer tension).
[0034] In one non-limiting embodiment, the first inner spacer assembly 104a' may include a first spacer and a second spacer separate from the first spacer. It will be appreciate that in certain embodiments, first inner spacer assembly 104a' may include just a single spacer. The first spacer of the first inner spacer assembly 104a' may be connected to a first side of the planar portion of spider arm 102 and the second spacer of the first inner spacer assembly 104a' may be connected to the second side of the planar portion of the spider arm 102.
[0035] It will be appreciated that the respective spacers of respective inner assemblies 104a', 104a" may be optionally affixed to both sides of the planar portion of the spider arm 102, or to one side of the planar portion of the spider arm 102. Additionally, the respective spacers of respective inner assemblies 104a', 104a" may be optionally affixed in alternating manner to the opposite sides of the planar portion of the spider arm 102.
[0036] In one non-limiting embodiment, at least one fastener 142 (e.g., nut and bolt) may be used to affix the first spacer of the first inner spacer assembly 104a' to the first side of the planar portion of the spider arm 102 and to affix the second spacer of the first inner spacer assembly 104a' to the second side of the planar portion of the spider arm 102. As noted above, it is possible to use an alternative modality or combination of modalities —in lieu of at least one fastener— to transfer compression and tensile loads, such as could include a geometric bearing feature (e.g., compression) or an adhesive (e.g., tension)
[0037] As illustrated in FIG. 6, in certain embodiments, such may involve a stacked arrangement of winding packages, a second attachment flange 100' may be coupled to a second spider arm 102' disposed at the second reactor end. Second attachment flange 100' includes an inner portion 108' and outer portions 110'. In this case, the inner portion 108' is coupled to the end of second spider arm 102'. A second end of first inner spacer assembly 104a' opposite the first end of first inner spacer assembly 104a' is coupled to second spider arm 102'. Similarly, a second end of the first outer spacer assembly 104b' opposite the first end of first outer spacer assembly 104b' is coupled to the outer portions 110' of second attachment flange 100'.
[0038] In operation, when a lateral load (schematically represented by arrow Lf in FIG. 3) acts on the first side or the second side of the planar portion of the spider arm 102, this load would cause a bending moment on spider arm 102. In disclosed embodiments, this bending moment is opposed by the first and second outer spacer assemblies 104b', 104b", as opposed to being left unrestrained, as is the case in certain known arrangements. For example, in disclosed embodiments, one of the first and second outer spacer assemblies 104b', 104b" would be in compression while the other of the first and second outer spacer assemblies 104b', 104b" would be in tension. In this example, first outer spacer assembly 104b' would be in compression and second outer spacer assemblies 104b" would be in tension.
[0039] Therefore, disclosed embodiments are effective to counterbalance such moments and improve the structural capability of the mechanical connection between the spacers and the spider units
[0040] While embodiments of the present disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the scope of the invention and its equivalents, as set forth in the following claims.