Abstract:
A method for handling busbars on wind power plants in which a power connection between a generator device disposed in an upper region of the wind power plant and a substation located at a base area of the wind power plant consists of a plurality of busbar subregions each comprising a certain number of mutually interconnected busbars.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a method for handling, in particular for repairing of replacing, busbars on wind power plants. The invention further relates to a method for handling, in particular for repairing or replacing, bus bars on wind power plants. 
         [0002]    In the transmission of the power generated in a generator in the region of the top of a tower of a wind power plant into a substation arranged at the base of the wind power plant, a differentiation is basically made between two methods: In the first method, the power is transmitted via a cable from the generator to the substation. In the second method, the power transmission takes place by means of busbars. Here, for bridging the distance between the base region and the head of the tower of the wind power plant, usually a plurality of busbars are used, connected or respectively screwed to one another, which have, for example, a typical length of approximately 3 m. 
         [0003]    The tower of a wind power plant generally consists of several tower segments arranged on top of one another, which are respectively constructed in a sleeve shape. During the manufacture of the wind power plant, in the second method for power transmission the busbars are already fixed to the inner wall of the respective tower segment during the manufacture of the tower segments, so that the busbars arranged or respectively fixed inside a tower segment form a busbar subregion. After the placing of the individual tower segments on one another in situ, the individual busbar subregions of the tower segments are electrically contacted or respectively coupled with one another by means of connection bars. The individual busbars of a busbar subregion are elastically fixed or respectively suspended within the tower segment by means of a fixing device, having a bracket, via an elastomer element, serving as intermediate element, in a bolt, which in turn is anchored in the wall of the tower segment. 
         [0004]    On mounting and especially during the operation of the wind power plant, in the course of time, for example as a result of different thermal expansions between the tower of the wind power plant, consisting of steel, and the busbars, usually consisting of aluminium, mechanical stresses occur within a busbar subregion and between the individual busbar regions, which are to be balanced out through the elastic suspension of the busbars by the elastomer elements. Furthermore, as a result of the elastic suspension of the busbars via the elastomer elements, the weights of the individual busbars are partially transferred to the busbars respectively arranged beneath. 
         [0005]    Owing to the special geometric construction of the busbars, it is not possible, without the risk of damage to individual busbars, to remove an individual busbar from a busbar subregion due to a necessary repair or a necessary replacement. Firstly, the connection bar arranged above the affected busbar subregion to the next busbar subregion must be disconnected. Only then can a replacement take place of the busbar which is to be repaired or respectively replaced by removing all busbars of the affected busbar subregion above the busbar which is to be repaired or respectively replaced. On re-mounting the busbars of a busbar subregion, the procedures are repeated in reverse sequence. Owing to the elastic suspension of the busbars and the mentioned stresses between the busbars and between the busbar subregions, on re-mounting of the busbars additional stresses are introduced into the busbar interconnection formed from the individual busbar subregions, which can previously damage the busbar interconnection. Moreover, during the repair or replacement, the busbars of the busbar above that which is to be repaired or respectively replaced are partially stressed by the weight of busbars arranged above, so that these settle by a certain distance and therefore if applicable the elastomers of the relevant busbars can be previously damaged, which if applicable can not be detected visually. 
       SUMMARY OF THE INVENTION 
       [0006]    Proceeding from the presented prior art, the invention is based on the problem of further developing a method for handling, in particular for repairing of replacing, busbars on wind power plants such that a dismantling and mounting of individual busbars on a wind power plant is made possible, without additional stresses or respectively previous damage being introduced into the busbar interconnection composed of the busbars, or respectively that a simple replacement of busbars is made possible. 
         [0007]    The invention is based here on the idea of at least partially equalizing the weight of at least one busbar, arranged directly above or respectively below in particular the busbar which is to be repaired or respectively replaced, by means of a relief arrangement by applying a tensile force to the relevant busbar. Thereby, the inherent stresses between the individual busbars of a busbar subregion are at least reduced, in the best case are completely eliminated, so that the busbars can be removed or respectively dismantled and subsequently mounted again in a stress-free manner. 
         [0008]    Advantageous further developments of the method according to the invention and its device are indicated in the subclaims. All combinations of at least two of the features disclosed in the claims, in the description and/or in the figures fall within the scope of the invention. 
         [0009]    In a preferred embodiment of the invention, it is proposed that the weights of all busbars of a busbar subregion, in which the busbar which is to be repaired or replaced is situated, are at least partially, preferably completely, equalized by means of the relief arrangement. Thereby, in particular after the re-mounting of the busbars of a busbar subregion has been completed, inherent stresses between the busbars in the busbar subregion are reliably prevented. 
         [0010]    In a most especially preferred method, it is additionally proposed that in addition also the weights of those busbars of the busbar subregions are at least partially equalized which are situated beneath or respectively above the busbar subregion with the busbar which is to be repaired or respectively replaced. Thereby, the entire busbar interconnection between the generator and the substation at the foot of the wind power plant is arranged in a stress-free manner, so that any stresses which may be present in the busbar interconnection in the interim as a result of the operation of the wind power plant can be completely removed. Thereby, an undisturbed operation of the wind power plant in the region of the busbar interconnection, taking place over longer period, is made possible, because damage as a result of stresses between the busbars can be prevented. 
         [0011]    Furthermore, it is most particularly preferred if at least one elastic fixing element, associated with the fixing device of the busbar which is to be repaired or respectively replaced, is replaced together with the relevant busbar. Thereby, possible future damage owing to a previously damaged elastomer element or respectively fixing element is prevented. 
         [0012]    In order to ensure that during the dismantling of the busbars no further previous damage or respectively stresses can be introduced into the busbar interconnection, or respectively such stresses are prevented on re-mounting, in a further embodiment of the method according to the invention it is proposed that the equalizing of the weights of the busbars takes place by relieving the busbars from the direction of the generator device in the direction of the substation, by the weights of the busbars being equalized in succession, and that after completion of the repair or respectively replacement of the busbar, the weight loading of the busbars as a result of their own weight takes place from the direction of the substation in the direction of the generator device, by the busbars being brought out of operative connection in succession with the relief arrangement. 
         [0013]    A preferred device for carrying out a method according to the invention comprises a relief arrangement, which is able to be connected with the fixing device of a busbar and which has at least one tensioning device, by which the weight of a busbar is able to be equalized. 
         [0014]    In a first structural embodiment, which is suitable for the repair of individual busbars of a busbar subregion, provision is made that the relief arrangement is able to be secured on a fixing bolt for fixing the fixing device for the busbar. 
         [0015]    In a preferred structural embodiment of the device, which is suitable in particular to arrange the entire busbar interconnection of a wind power plant in a weight-free manner, in order for example to eliminate inherent stresses of all busbars or respectively to enable a replacement of all elastomers or respectively fixing devices of the wind power plant, provision is made that the relief arrangement has at least one carrying means, which in particular is able to be secured on the upper region of the tower of the wind power plant, and that the at least one carrying means for a plurality of busbars, preferably for all busbars, respectively has at least one tensioning device for weight equalization, which is able to be connected with the fixing device of the busbar. 
         [0016]    In order to prevent the introduction of transverse forces into the busbars, it is furthermore advantageous if the relief arrangement has two tensioning devices, able to be connected with the fixing device, for each busbar, and if the two tensioning devices are arranged symmetrically to the longitudinal axis of the busbar. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Further advantages, features and details of the invention will emerge from the following description of preferred example embodiments and with the aid of the drawings. 
           [0018]    These show in: 
           [0019]      FIG. 1  a greatly simplified longitudinal section through a wind power plant, 
           [0020]      FIG. 2  a front view, partially in section, in the region of the connecting site of two busbars within the wind power plant according to  FIG. 1  with a first relief arrangement according to the invention, 
           [0021]      FIG. 3  the first relief arrangement according to the invention, in simplified representation, 
           [0022]      FIG. 4  a side view onto a second relief arrangement according to the invention, and 
           [0023]      FIG. 5  a front view onto the second relief arrangement according to the invention, in accordance with  FIG. 4 . 
       
    
    
       [0024]    Identical components or respectively components with the same function are given the same reference numbers in the figures. 
       DETAILED DESCRIPTION 
       [0025]    In  FIG. 1  the basic structure of a wind power plant  10  is illustrated in a greatly simplified manner. The wind power plant  10  has a tower  11 , which is arranged on a base  12 . At the top of the tower  11   a  nacelle  13  is arranged, in which inter alia the rotor blades  14  are arranged in a rotatably movable manner. A generator  16  is situated within the nacelle  13 . The generator  16  is coupled with an upper connecting line  17  or an upper connection with a busbar interconnection  20 . The busbar interconnection  20  is arranged here in particular over the entire length or respectively height of the tower  11 . In the region of the base  12  of the tower  11 , the busbar interconnection  20  is connected by means of a further, lower connecting line  21  or respectively a lower connection with a substation  22 . 
         [0026]    The tower  11  consists for example of three respectively sleeve-like tower segments  24  to  26  arranged on top of one another. Such a tower segment  24  to  26  has here a typical length of approximately 20 m, so that the overall height of the tower  11  is approximately 60 m. The busbar interconnection  20  is already arranged or respectively fixed during the manufacture of the tower segments  24  to  26  within the individual tower segments  24  to  26 . For this, the busbar interconnection  20  within each tower segment  24  to  26  consists of a busbar subregion  27  to  29 . Each busbar subregion  27  to  29  consists in turn of several busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , for example approximately 3 m in length. 
         [0027]    Between the individual busbar subregions  27  and  28  the respectively uppermost busbars  27   f  and  28   f  are connected in an electrically conductive manner with the respectively lower busbars  28   a  and  29   a  of the busbar subregions  28  and  29  arranged above, by means of connection bars  31 ,  32 . 
         [0028]    Respectively two successive busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  are fixed to the inner wall  33  of the tower  11  by means of a fixing device  35  which can be seen in  FIG. 2 . For this, a bracket bolt  36  is securely anchored on the inner wall  33  of the tower  11 , which bolt carries the actual fixing device  35 . The fixing device  35  has a bracket angle  37  arranged transversely to the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , which bracket angle carries respectively a coupling element, constructed as elastomer element  38 , on both sides to the busbars  28   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f . The elastomer element  38 , constructed in particular in a cylindrical shape, is connected with a fixing angle  40  in the region of an elongated hole  39 , wherein the two fixing angles  40 , arranged on both sides of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  are in turn connected via screw connections  41 ,  42  with the respective busbars  27 - 1  to  27 - 6 ,  28 - 1  to  28 - 6  and  29 - 1  to  29 - 6 . 
         [0029]    As can be seen in particular from  FIG. 2 , the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  respectively have a busbar housing  43 , in which respectively the individual conductors  44  to  46 , which consist in particular of aluminium and have a rectangular cross-section, are arranged. The conductors  44  to  46  are connected with one another in a force-fitting manner in the connection region of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  by means of a transverse bolt  47  with interposition of isolators, which are not shown, in order to ensure the flow of current within the conductors  44  to  46 . 
         [0030]    For the repair or respectively replacement of individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  it is expedient to respectively remove in addition all busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  of a busbar subregion  27 ,  28 ,  29  above the busbar  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  which is respectively to be repaired or respectively replaced. For this, firstly in a first working step if applicable the connection bar  31  or respectively  32  arranged respectively above the busbar subregion  27  or respectively  28  must be removed. 
         [0031]    A device, illustrated in simplified form in  FIGS. 2 and 3  with a first relief arrangement  50  serves to enable, during the repair or respectively replacement of a busbar  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , a stress-free dismantling or respectively installation of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , unaffected by the weights of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  transferred via the elastomer elements  38  into the busbar subregions  27  to  29 . 
         [0032]    The first relief arrangement  50  preferably serves here to arrange all busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  at the same time at least partially in a weight-free manner, in order in particular to enable a low-stress, preferably stress-free overall alignment or respectively realignment of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  within the tower  11 . Preferably here at the same time the elastomer elements  38  of the fixing devices  35  can be replaced, so that any elastomer elements  38  previously damaged owing to stresses which occurred in the interim can not cause any breakdowns or respectively damage during the further operation. 
         [0033]    For this, the first relief arrangement  50  has a crossbeam  51 , which is fixed by means of a chain block  52 , only indicated symbolically, in particular in the machine mount of the nacelle  13 . A load chain  53 ,  54  is arranged respectively on both sides of the busbar interconnection  20  on the crossbeam  51 . Two tensioning devices  56 ,  57 , in particular in the form of turnbuckles  58 ,  59 , are associated with each busbar  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f . Here, each of the turnbuckles  58 ,  59  is able to be connected with an elongated hole  39  of a fixing angle  40 . The arrangement of the load chains  53 ,  54  is symmetrical to the longitudinal axis of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , so that any transverse forces introduced via the tensioning devices  56 ,  57  can be equalized. 
         [0034]    The weight-free setting of the busbar interconnection  20  takes place such that beginning from the uppermost busbar  29   f  arranged in the tower  11 , the busbars  29   e  to  29   a ,  28   f  to  28   a  and  27   f  to  27   a  are set weight-free in succession in the direction of the base  12  by means of the tensioning devices  56 ,  57 . For this, the position of the individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  or respectively of the fixing devices  35  is checked, until it is ensured that by means of the tensioning devices  56 ,  57  the weight of the respective busbar  27   a  to  27   f ,  28   a  to  27   f  and  29   a  to  29   f  is equalized or respectively compensated. As soon as this has taken place with all busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , the entire busbar interconnection  20  is free of stress, so that in particular the elastomer elements  38  on the individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  can be replaced. After replacement of the elastomer elements  38 , the individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  are loaded again with their own weight in reverse sequence, i.e. from the direction of the base  12  in the direction of the nacelle  13 , by the respectively tensioning devices  56 ,  57  being removed. 
         [0035]    In  FIGS. 4 and 5  a modified device is illustrated with a second relief arrangement  60 . The second relief arrangement  60  serves to replace or respectively repair individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  of a busbar subregion  27  to  29 . For this, the second relief arrangement  60  has a supporting structure  62 , which comprises for example a U-shaped carrier  63 , which is able to be secured or respectively fixed on a bracket bolt  36 . A tensioning device  64 , having a tensioning bolt, serves for this. The supporting structure  62  has, in addition, two crossmembers  65 ,  66  arranged on both sides of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f . A tension bolt  67 ,  68  is arranged so as to be axially adjustable respectively on the crossmembers  65 ,  66 , which tension bolt engages into the respective elongated hole  39  of a fixing angle  40 . 
         [0036]    During the repair or respectively replacement of individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  in a busbar subregion  27  to  29  generally several second relief arrangements  60  come into use simultaneously, which are connected with at least the busbar  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  directly above or respectively below that which is to be replaced or respectively repaired, via the respective fixing device  35 , in order to set the respective busbar  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  at least partially, preferably completely free of weight. In particular, on reassembling the individual busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f , the latter are respectively set in a force-free manner before the respectively next, upper busbar  27   b  to  27   f ,  28   a  to  28   f  or respectively  29   a  to  29   f  is mounted. 
         [0037]    The relief arrangements  50  or respectively  60  described so far can be altered or respectively modified in a variety of ways, without departing from the idea of the invention. It is only essential that these are suitable for the at least partial, preferably for the entire weight-free setting of busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f . It is mentioned in addition that the tower  11  can also have different dimensions than those described and illustrated. Thus, for example, it is possible that the tower  11  has a height of approximately 80 m and is constructed from more (or fewer) tower segments. 
         [0038]    Furthermore, it is mentioned that the invention was described in the example embodiments by means of a replacement or respectively a repair of busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f . However, it is also within the scope of the invention to use the relief arrangements  50 ,  60  for the first installation of the busbars  27   a  to  27   f ,  28   a  to  28   f  and  29   a  to  29   f  and, after their installation, to remove the relief arrangements  50 ,  60  from the wind power plant  10 .