Abstract:
A single- or multi-phase dry-type transformer includes at least two coils. A barrier between phases made of an electrically insulating material is arranged in the intermediate space between the individual coils.

Description:
RELATED APPLICATION(S) 
     This application claims priority as a continuation application under 35 U.S.C. §120 to PCT/EP2011/003160, which was filed as an International Application on Jun. 28, 2011 designating the U.S., and which claims priority to European Application 10007133.1 filed in Europe on Jul. 10, 2010. The entire contents of these applications are hereby incorporated by reference in their entireties. 
    
    
     FIELD 
     The present disclosure relates to a single-phase or polyphase dry-type transformer with at least two coils. 
     BACKGROUND INFORMATION 
     In the case of three-phase transformers, the three coils are generally arranged next to one another at an electrically safe distance. For instance, at high voltages, the distances between the coils associated with the three phases are relatively large in order to withstand the voltage loads during the surge voltage withstand testing. This results overall in a less compact design of the transformer. 
     SUMMARY 
     An exemplary embodiment of the present disclosure provides a single-phase or polyphase dry-type transformer which includes at least two coils having an interspace arranged therebetween, and an interphase barrier comprised of an electrically insulating material and arranged in the interspace between the at least two coils. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional refinements, advantages and features of the present disclosure are described in more detail below with reference to exemplary embodiments illustrated in the drawings, in which: 
         FIGS. 1 to 6  show exemplary embodiments of interphase barriers according to the present disclosure; 
         FIGS. 7 to 13  show exemplary embodiments of spacers with respect to a pressing bar/yoke of a dry-type transformer according to the present disclosure; and 
         FIGS. 15 and 16  show exemplary embodiments of interphase barriers equipped with spacers. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides a single-phase or polyphase dry-type transformer with at least two coils which enables a compact design even at high voltages. 
     An exemplary embodiment according to the present disclosure provides a single-phase or polyphase dry-type transformer having at least two coils, wherein an interphase barrier made of (e.g., including in whole or in part) an electrically insulating material is arranged in the interspace between the individual coils. 
     Two coils can also be used for a single-phase transformer, in which one coil is arranged on each limb of a core with two limbs. 
     Due to the arrangement of the interphase barriers in the interspace between the individual coils, the required distances between the coils can be significantly reduced. A compact design of the dry-type transformer is thus achieved. In this case, both an individual barrier and a plurality of barriers arranged next to one another can be used per interspace. Such barriers can be connected to one another by means of spacers, which, for example, may not be arranged in the peripheral region in order thus to increase the leakage path as efficiently as possible. Furthermore, in accordance with an exemplary embodiment, a leakage path extension in the form of spacers can be attached to the ends of the barrier in the direction of (grounded) pressing bars/yokes. 
     Additional features of the present disclosure are explained in more detail below with reference to exemplary embodiments illustrated in the drawings. 
       FIGS. 1 to 6  illustrate exemplary embodiments of interphase barriers according to the present disclosure. In the drawings, a view of three coils  1 ,  2 ,  3 , which are arranged next to one another, of a three-phase dry-type transformer is shown, wherein in each case one interphase barrier made of (e.g., including in whole or in part) an electrically insulating material is provided between the coils  1  and  2  and between the coils  2  and  3 : 
     As shown in  FIG. 1 , plate-shaped barriers  4  in the form of straight, planar, rectangular plates with a predetermined length, width, and height are used as interphase barriers. 
     As shown in  FIG. 2 , in each case leakage path extensions  5  are attached to the outer edges (ends) of the plate-shaped barriers  4  as an extension of the configuration in  FIG. 1 . These leakage path extensions  5  can have, for example, a triangular cross section, as is shown. 
     As shown in  FIG. 3 , integral moldings  6  are used for forming the interphase barriers. These integral moldings  6  expediently have, for example, at their outer edges, integrated shapings which extend the leakage path. 
     As shown in  FIG. 4 , each interphase barrier is formed in two parts in the form of two plates  7 ,  8  arranged parallel next to one another. 
     As shown in  FIG. 5 , in each case a plurality of spacers  9  are arranged between the two plates  7 ,  8 , as an extension of the configuration shown in  FIG. 4 . In accordance with an exemplary embodiment, the spacers  9  may not be arranged in the edge region, but offset with respect thereto in the direction toward the center of the plate, in order to thus ensure an extension of the leakage path. 
     As shown in  FIG. 6 , as a modification of the embodiments shown in  FIG. 4  or  5 , two plates  10 ,  11  arranged parallel to one another are provided with a respective bent-back end piece as parts of the interphase barrier, wherein spacers  9  are optionally provided between these plates  10 ,  11 . 
       FIGS. 7 to 13  illustrate exemplary embodiments of spacers with respect to a pressing bar/yoke of a dry-type transformer. These spacers are used for creating a defined distance between the interphase barrier and the conventionally grounded pressing bar/yoke of the dry-type transformer. The spacers can be made of (e.g., including in whole or in part) a block of electrically insulating material with at least one slot in its upper side for receiving an interphase barrier, wherein at least one insulating plate protrudes beyond the side faces of the block in order to thus achieve a leakage path extension. The bottom side of the block comes into contact with the pressing bar/yoke.  FIGS. 7 to 10  show a view of a spacer: 
     As shown in  FIG. 7 , the spacer  13  has a slot  15  in the block  14  beyond which at least one insulating plate  16  protrudes on all sides. The width of this slot  15  corresponds to the width of the plate-shaped barrier  4  or the width of the integral molding  6  or the width of the configuration “plate  7 +spacer  9 +plate  8 ” or the width of the configuration “plate  10 +spacer  9 +plate  11 ”. 
     As shown in  FIG. 8 , the spacer  19  has two parallel slots  20 ,  21  in the block  14 , beyond which at least one insulating plate  16  again protrudes on all sides. The width of these slots  20 ,  21  corresponds to the width of the plates  7 ,  8  or  10 ,  11 . In accordance with an exemplary embodiment, when using the spacer  19 , there is no need for the spacer  9  between the plates  7 ,  8  or  10 ,  11 . 
     As shown in  FIG. 9 , the spacer  23  has a slot  24  in the block  14 , which slot is closed at one end, which has the advantage that an additional lateral fixing of the interphase barrier is provided, for example, this spacer  23  can be used in the corner regions of the interphase barrier. 
     As shown in  FIG. 10 , the spacer  26  has two slots  27 ,  28  in the block  14 , which slots are closed at one end, which has the advantage that an additional lateral fixing of the plates  7 ,  8  of the interphase barrier is provided, for example, this spacer  26  can likewise be used in the corner regions of the interphase barrier. 
       FIG. 11  shows, in supplementary fashion to  FIGS. 7 and 9 , a side view of a spacer  13  or  23  with block  14 , slot  15  or  24  and three parallel insulating plates  16 , wherein the bottom side  17  of the block  14  comes into contact with a pressing bar/yoke. 
       FIG. 12  shows, in supplementary fashion to  FIG. 11 , a side view of a practical application of a spacer  13  or  23  with a configuration “plate  7 +spacer  9 +plate  8 ” inserted into the slot  15  or  24  for providing the interphase barrier. 
       FIG. 13  shows, in supplementary fashion to  FIGS. 8 and 10 , a side view of a spacer  19  or  26  with block  14 , slot  20  or  27 , slot  21  or  28  and three parallel insulating plates  16 , wherein the bottom side  17  of the block  14  comes into contact with a pressing bar/yoke. 
       FIG. 14  shows, in supplementary fashion to  FIG. 13 , a side view of a practical application of a spacer  19  or  26  with a plate  7  inserted into the slot  20  or  27  and with a plate  8  inserted into the slot  21  or  28  for providing the interphase barrier. 
       FIGS. 15 and 16  show exemplary embodiments of interphase barriers equipped with spacers.  FIG. 15  shows an interphase barrier provided between the coils  1  and  2 , which interphase barrier is formed from a configuration “plate  7 +a plurality of spacers  9 +plate  8 ”, wherein this configuration is inserted in each case into the slots  15  of spacers  13  at the lower and upper outer edge of the configuration. 
       FIG. 16  shows an interphase barrier provided between the coils  2  and  3 , which interphase barrier is formed from two plates  7 ,  8 , wherein these plates are inserted into the slots  27 ,  28  in spacers  26  at the lower and upper outer edge of the plates in the corner regions. 
     It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein. 
     LIST OF REFERENCE SYMBOLS 
     
         
           1  Coil 
           2  Coil 
           3  Coil 
           4  Plate-shaped barrier as interphase barrier 
           5  Leakage path extensions at the ends of plate-shaped barrier 
           6  Integral molding for forming an interphase barrier 
           7  Plate as part of an interphase barrier 
           8  Plate as part of an interphase barrier 
           9  Spacer 
           10  Plate with respectively bent-back end piece as part of an interphase barrier 
           11  Plate with respectively bent-back end piece as part of an interphase barrier 
           13  Spacer with respect to a pressing bar/yoke of a dry-type transformer 
           14  Block 
           15  Slot 
           16  Insulating plate 
           17  Bottom side of block 
           19  Spacer with respect to a pressing bar/yoke of a dry-type transformer 
           20  Slot 
           21  Slot 
           23  Spacer with respect to a pressing bar/yoke of a dry-type transformer 
           24  Slot closed at one end 
           26  Spacer with respect to a pressing bar/yoke of a dry-type transformer 
           27  Slot closed at one end 
           28  Slot closed at one end