Abstract:
A box-shaped electric control cabinet is provided which can be closed by a cover and which is used to receive electric components and devices for a blade angle adjustment drive (pitch drive) of a wind energy power plant, by means of which one or more rotor blades of the plant can be rotated about the blade axis. The control cabinet includes at least two cabinet segments, and specific electric components and devices are associated with respectively each module according to its function. The cabinet segments can be associated with and/or assigned to respectively different electric components and devices, with which, combined as a part function, different total functions and/or embodiment forms of the control cabinet can be produced or are producible.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 U.S. National Stage of International Application No. PCT/EP2011/003339, filed Jul. 5, 2011, and claims priority to German Patent Application No. 10 2010 034 873.2 filed Aug. 19, 2010, the disclosures of which are herein incorporated by reference in their entirety. 
     FIELD 
     The invention relates to a box-shaped electrical switchgear cabinet sealed with a cover of a wind turbine In particular, the invention relates to the geometric arrangement and exchangeability of switchgear cabinet segments. The invention also relates to a wind turbine with a box-shaped electrical switchgear cabinet sealed with a cover. 
     BACKGROUND 
     Modern wind turbines have rotor blades rotatably mounted on a rotor, it being possible to vary an angle of incidence of the wind through an individual change of the blade angle relative for each rotor blade. The change takes place through a pitch drive which is connected to an external mains supply and has a controllable electric motor, to which, as well as to a converter, control and regulating devices are assigned for adjusting the rotor blade, which are arranged in an electrical switchgear cabinet (pitch switchgear cabinet). Essential components of a pitch switchgear cabinet are electronic converter units for the controlled drive of the pitch system. Such a cabinet is thus also designated as a converter box. A converter box has e.g. electrical or electronic components and equipment such as e.g. mains adapters, circuit breakers and plugs, input/output units, fuses, transformers and other parts and equipment, which are also provided in a classic switchgear cabinet for an electrical drive. 
     An individual pitch drive with an associated control cabinet is usually assigned to each blade (axis), so that a plurality of pitch switchgear cabinets are provided in a wind turbine (WEA) which are usually arranged on the upper masthead (top box) of the turbine and configured as a compact box sealed with a cover. They are arranged there either in the rotating part (hub) and/or in the fixed part of the turbine (gondola), being preferably arranged, however, close to the support of the rotor blade in the hub. If the control of the pitch system runs in a coordinated manner for a plurality of axes, what is known as a master control cabinet (control box) can additionally be provided in the hub or also in the gondola, which is interconnected to the associated axis boxes. 
     Due to the installation site and the mounting location, these boxes are exposed to particularly extreme weather conditions. 
     In the event of power interruptions or power failure it must be ensured that the voltage supply of the pitch drive is maintained at least for a short time. Each pitch drive therefore also has additional direct voltage sources arranged in the rotor or in the gondola in the form of accumulators or rechargeable capacitors, which are directly connected to the respective drive unit (converter+motor). This voltage source ensures that in the event of failure of the mains supply, the energy supply of the pitch drive is maintained at least for a certain time. Through an actuation of the motor, the respective rotor blade is brought into what is known as the feathering position or parking position and the turbine thus shuts down or operates further only with secure rotary speed (Fail Safe Function). Due to the mounting location, the rechargeable direct voltage sources with the associated switches are also enclosed in a box-shaped cabinet (accumulator box), which is usually arranged close to the associated axis box. 
     Converter box and accumulator box thus form a switchgear cabinet combination of two or a plurality of cabinets or boxes which are directly connected to each other or are adjacently arranged. 
     A wind turbine with three rotor blades can have up to 7 switchgear cabinets which are constructed differently according to requirements and function and must each be made individually. The different switchgear cabinets are today also constructed in a modular manner to an extent, i.e. the individual components are assembled according to their function and each form either an individual module or segment or the arrangement has a plurality of module housings which are mechanically and electrically connected to each other. 
     A DE patent application of the applicant not yet published on the priority date having the publication number DE 10 2009 044 034 A1 shows a wind turbine with an electrical switchgear cabinet arrangement in which a circuit for actuating at least one blade adjustment drive (pitch system) is provided by means of which one or a plurality of rotor blades of the wind turbine can be rotated about their blade axes. The switchgear cabinet arrangement has a plurality of modules which are assembled in one compact and radially central container, the inner space of which is divided into a plurality of segments (modules) in particular by partitions. The partitions form a switchgear cabinet or module with the wall of a segment, to which switchgear cabinet or module a certain function is assigned. 
     Thus a module is provided for the function of the accumulator cabinet, another module for the function of the converter cabinet, a further module for the function of the control cabinet and optionally further modules for other functions. The individual modules can each form a separate structural unit which can also be made separately. However, the above-mentioned special electrical function is assigned to each module or honeycomb. Interchangeability between the functions is not provided for with the individual modules. 
     Switchgear cabinets constructed in a modular manner are known from the general switchgear cabinet structure (e.g. DE 102 41 574 B4) which have a plurality of module housings and are connected to each other via a connection element. The module housings can each have a series of electrical plug connections which are either led outwardly or are provided for connecting the module housings. 
     A switchgear cabinet with a switchgear cabinet box having a plurality of modules fixed to a support rail is known from DE 197 43 974 A1, a certain function being assigned to each individual module. The switchgear cabinet is only function-block orientated and modularly constructed. The modules do not differ in their technical function from a classic switchgear cabinet, rather only in their simpler mode of installation and/or upgrading. 
     The substantial disadvantage of the known solutions is that with an increasing number of electrical components, caused by technical changes to the wind turbine, the layout of the switchgear cabinet must be enlarged. A further cabinet or a module must be added to the existing switchgear cabinet arrangement if necessary. If a higher level of equipping is required, e.g. if the additional or larger components are required, a new cabinet is designed or an additional housing module is added to the existing arrangement. 
     With identical parts or identical functions of switchgear cabinets, the turbine operator therefore always has to design and make new switchgear cabinets with the corresponding content for altered technical requirements, which switchgear cabinets have be produced individually, held in stock and have to each be fitted. This makes switchgear cabinet production expensive and laborious. 
     Since there is limited space available in the current hubs of wind turbines, the optimal balance between necessary space for electrical components and the size of the hub has to be established. It is not unusual that axis cabinets in particular cannot once again be removed following installation in the hub without the blades of the WEA having to be dismounted. In the small space conditions in the hub, this involves significant effort or is usually not possible. In the case of a complete failure of a pitch system, the hub, including the blades, usually has to be removed from the gondola. The blades are then dismounted on the ground in order to remove the axis switchgear cabinets through the blade bearing openings and to optionally install new switchgear cabinets or modules. 
     SUMMARY 
     An object of the invention is to flexibly design and to improve the production and fitting of switchgear cabinets according to technical requirements. It is also intended to improve the installation and the dismounting of such switchgear cabinets. 
     The object of the invention is achieved in connection with the preamble of claim  1  through its characterising features. Advantageous developments of the inventive solution result from the subclaims. 
     The invention is based on a modular system, with which different switchgear cabinets or switchgear cabinet arrangements can be implemented according to requirement and function. The modular system in this connection is designed such that different functions can be implemented with few modular components and with switchgear cabinet segments or modules. The individual modular components can thus be produced in higher quantities and optionally as series production using automatic machines and even held in stock. This leads to lower production costs. With few modular components, different cabinets with different functions can thus be produced cost-effectively and flexibly. The functions can be shown for a corresponding arrangement of the modular components. 
     The overall function of a switchgear cabinet comprises on the one hand certain basic functions which recur over and over and to which a basic modular component in the form of a basic module is assigned. Further auxiliary functions, which operate subsequently or conjunctively, and to which an auxiliary modular component is thus assigned as an auxiliary module. As a further subfunction of the overall function, special functions are provided which are particularly supplementary and enhancing and to which a special modular component or special module is thus assigned. The overall function further comprises adapting functions which cannot exactly be fixed in all parts and to which an adapting modular component or an adapting module is assigned. 
     The modular system can be additionally supplemented by what is known as a mixing system which includes request-specific functions, which are not foreseeable and to which what is known as a “non modular component” or a non module is assignable. 
     Different variants of the overall function of a switchgear cabinet can thus be assigned to certain modular components or switchgear cabinet segments, which used flexibly, result in different switchgear cabinets. The different modular components or modules can be pre-made according to their function mentioned above, optionally held in stock and flexibly assembled to form a switchgear cabinet with a different function. 
     From the prior art, it was hitherto only known to assign a certain functional modular component to an individual module and not—as proposed in the invention—to be able to use the one and the same module or segment for different functions. 
     Through the flexible, modular structure of the switchgear cabinet, the individual segments or modules can be mounted or later subsequently dismounted at difficult to access points e.g. above in the wind turbine, without requiring great effort to more easily assemble a switchgear cabinet in the hub or in the nacelle, since the individual segments have smaller dimensions than a complete switchgear cabinet. This in turn brings about, in addition to the lower production costs and maintenance costs, greater availability of the turbine. 
     Preferably the segments and modules of the switchgear cabinet consist of metal, in particular stainless steel, of coated steel or of another material, such as for example plastics, which is suitable for use in wind turbines. 
     In an advantageous embodiment, a plurality of different segments or modules is arranged successively or adjacently. Successively arranged, they form a compact, box-shaped switchgear cabinet which is open from above. Transverse thereto further box-shaped switchgear cabinets, with a different function however, can be presented by a combination of identical segments or modules. The switchgear cabinets or switchgear cabinet arrangements resulting from such a combination can in this connection either be arranged directly adjacently or at a distance from each other. 
     Each segment and module advantageously has an individual cover, a common covering of all segments or modules also of course being possible. The individual or common cover is made from the same material or another suitable material as the individual modules or segments. 
     Within the framework of the modular system, it is advantageous to reduce the number of segments or modules to a minimum. For the provided function of the switchgear cabinet, only three different modules or segments are required for the pitch drive, an end cap module, an outer segment and a central segment. The segments or modules in one first embodiment of the invention are thus assignable to the spatial arrangement in the switchgear cabinet. 
     For example an end cap as mounting plate for the installation of electrical components and equipment of the switchgear cabinet and the supports thereof can be provided in the switchgear cabinet constructed in a segmented or modular manner. A further end cap opposite the first end cap could be provided as a plug panel for the electrical connection outwards or to another adjacent switchgear cabinet or switchgear cabinet module. In this connection, the end cap of the plug panel can comprise surface stamps for the arrangement of plugs or plug panels on its surface. If small or only very few stamps are required, this end cap is constructed virtually identically as its mounting plate opposite and can accordingly also be used as such. 
     The requirement of the modular system with as few as possible identical modular components to implement various functions of the switchgear cabinet, is further advantageously realised in that the two outer segments and the central segment enclosed by the two outer segments comprises a virtually identical structure in their basic structure. This has the advantage that one and the same segment can be used either as the outer segment or as the central segment. In a further embodiment of the invention, the spatial assignment of the segments or modules is thus removed. 
     A segment or module consists of a U-shaped, planar frame construction with a rectangular closed or open base surface extending horizontally, which is surrounded by frame parts and has planar frame lateral parts protruding laterally and perpendicularly. The central segment is connected in each case to a longitudinal frame part and a lateral frame part with the corresponding frame parts of an outer segment. 
     According to their function and the use, the U-shaped segment parts (outer segment and/or central segment) are configured with different widths. 
     The two outer segments and the central segment are further distinguished in that they each have partly open and/or closed base or lateral surfaces, according to the function for which they are used. Both segments or modules are thus in principle interchangeable and can be produced as a single element which only needs to be adapted according to its use by stampable openings in the lateral surfaces or in the base surface. 
     In order to implement the closed box shape of the switchgear cabinet, the surface of the outer segment pointing outwards is covered between the two frame lateral parts by an end cap in each case. The lateral frame parts of the central segment can form a closed surface on both sides or have openings in its closed base surface. In the lateral walls of the outer segment open surfaces can be produced e.g. subsequently by stamps. Switches or connection parts or other electrical components can be fixed outwardly in the stamped openings in one of the lateral walls of the outer segment. 
     With the modular system, a switchgear cabinet arrangement, which has a plurality of individual switchgear cabinets, can also advantageously be implemented with the two segments or modules described above as the modular component. 
     A converter cabinet (converter box) can on the one hand be produced with the two segments, in which converter cabinet all equipment and devices for the conversion of power are arranged, as they are provided in a classic switchgear cabinet. This cabinet is producible separately as a partial cabinet and can thus be combined separately in different ways, above in the hub or in the gondola of the wind turbine with other cabinets by means of screws, bolts or rivets and then later dismounted. 
     A container can, however, also be produced with virtually the same elements as the converter box which only has rechargeable voltage sources in the form of accumulators or capacitors with their associated switches which ensure an emergency power supply in the event of a failure of the power supply of the pitch drive, in order to immediately rotate the rotor blades to a parking or feathering position. For safety reasons (degassing) such an “accumulator box” is provided separately from that of the converter box. 
     In a further embodiment, both boxes—and any further additional boxes, if necessary—are thus constructed in principle from only one identical part, a U-shaped segment part which is either usable as the outer segment or the central segment. 
     Further types of embodiment and variations of the invention emerge from the subclaims and the exemplary embodiments shown below in the drawing. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  shows a perspective representation of a first embodiment of the invention. 
         FIG. 2  shows  FIG. 1  in an exploded representation. 
         FIG. 3  shows a perspective representation of a further embodiment of the invention. 
         FIG. 4  shows  FIG. 3  as an open switchgear cabinet combination. 
         FIG. 5  shows a schematic representation of a modular system with assignable modular components for the production of a modular switchgear cabinet. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
       FIG. 1  shows an electrical switchgear cabinet  2  configured in a box-shape and closed with a cover  1 , in which electrical equipment and switches (not shown) are arranged for controlling a blade angle adjustment drive (pitch drive) of a wind turbine (WEA) by means of which one or a plurality of rotor blades of the turbine are rotatably adjustable about their blade axes. Essential components of such a switchgear cabinet are the electronic converter units for the controlled drive of the pitch system. These cabinets are therefore also designated as converter box  3 . The converter box  3  comprises e.g. electrical or electronic elements and equipment such as e.g. mains adapters, circuit breakers and plugs, input/output units, fuses, transformers and other parts and equipment, which are also provided in a classic switchgear cabinet for an electrical drive. 
     The converter box  3 , functioning as an electrical switchgear cabinet, is assembled from three modules or segments of a modular system  21  which are arranged successively. The modules or segments thus form modular components  22  of the modular system  21 . The structure of such a modular system  21  with individual modular components  22  can be seen in  FIG. 5 . 
     By means of the modular system  21  shown in  FIG. 5 , the converter box  3  has been assembled in  FIG. 1  and in  FIG. 2 . In the centre of the converter box  3 —as can be seen in particular in  FIG. 2 —a U-shaped central segment  4  is arranged, which is connected at its lateral edge, both right and left, in each case with a likewise U-shaped outer segment  5 . Both outer segments  5  and the central segment  4  are tightly, but separably, connected along their longitudinal side via corresponding connection means. The two outer segments  5  and the central segment  4  enclosing them are constructed substantially identically, as can also be seen in  FIG. 2 . They are distinguished in the embodiment as converter box  3  only in their lateral length. The two outer segments  5  are shorter than the central segment  4  in the embodiment according to  FIG. 1  and  FIG. 2 . However, they can also have the same lateral length as the central segment  4 . 
       FIG. 2  shows an exploded representation of the modular structure of the converter box  3 . The two outer segments  5  are covered on their longitudinal side directed outwards by an end cap  6   a ,  6   b  in each case which thus close the box in the longitudinal direction. The two end caps are also constructed virtually identically. Each cap  6   a ,  6   b  comprises a plate, the surfaces of which are stampable according to requirements so that they form open or closed surfaces. 
     With the end cap  6   a  shown in the front region of  FIGS. 1 and 2 , the surfaces are stamped in the manner of two adjacent windows  9  ( FIG. 1 ). Each window  9  has a plug panel  7  ( FIG. 1 ), in which plugs are arranged for connection of the power supply or for communication with the pitch drive or with a superordinate controller of the WEA. The rear end cap  6   b  is provided as a mounting plate  8  for installing equipment or switches. Alternatively, the non-stamped front end cap  6   a  could also be used for this cap. 
     The U-shaped central segment  4  and the two outer segments  5  in each case consist of a base surface  10  and perpendicular thereto lateral surfaces  11  protruding laterally. The base surface  10  and the two lateral surfaces  11  are delimited by frame parts  12  which are connected to each other and to the adjacent frame (see  FIG. 1 ). In the embodiment of the switchgear cabinet  2  as an accumulator box  3 , all base surfaces  10  are closed. However, the lateral surfaces  11  have a different surface design. The two rear lateral surfaces  11  of the two outer segments  5  are closed, while their front lateral surfaces  11  have an opening  13  over their entire surface, which is, however, sealed with a stampable plate  14  ( FIG. 1 ). On the plate  14  of the front outer segment  5 , a switch panel  23  is provided for mounting switches and similar devices. In the case of the front plate  14  ( FIG. 1 ) of the rear outer segment  5 , the plate  14  is, however, not stamped. The two lateral surfaces  11  of the central segment  4  form, at front and rear, a closed surface. A lighting device  15  ( FIG. 1 ) for the hub of the wind turbine is additionally arranged on the front lateral surface  11 . 
       FIG. 3  shows a switchgear cabinet arrangement  16  assembled from individual modules  4  and  5 . The switchgear cabinet  16  consists of a combination of two successively arranged switchgear cabinets  2 , which are in each case covered by a cover  1 . 
     During the further course of the description, identical elements or functions are provided with the same reference numerals. 
     The switchgear cabinet  16  is produced with the modular system  21  according to  FIG. 5 , with an additional switchgear cabinet  2 , which is constructed from virtually the same modular components  22 , i.e. segments and modules ( 4 ,  5 ) as the converter box  3  from  FIG. 1  and  FIG. 2  described above. The further switchgear cabinet  2  is arranged laterally (in  FIG. 3  and  FIG. 4  to the left) on the converter box  3 . The switchgear cabinet  2 , according to the modular system  21  from  FIG. 5 , is assembled from virtually the same segments or modules as the converter box  3 . 
       FIG. 4  shows the switchgear cabinet  16  from  FIG. 3  without the covers  1 , and without contents, so that the modular structure of both cabinets can be seen. 
     The second switchgear cabinet  2  is what is known as an accumulator box  17 , a container, in which rechargeable direct voltage sources in the form of accumulators (thus the designation accumulator box) or rechargeable capacitors and the interconnections thereof are arranged. For safety reasons, the accumulators must be arranged in a separate container, the accumulator box  17 . The accumulators arranged in the accumulator box  17  (or other rechargeable voltage sources) have the object of ensuring the power supply to the associated pitch drive for a short time in the event of power interruptions or a power failure. 
     In  FIG. 4 , modular structure of the accumulator box  17  is seen to be virtually identical to that of the adjacent converter box  3 . It can be seen from  FIG. 4  that the accumulator box  17  consists of a central segment  4  to which outer segments  5  are laterally, assigned. On both outer surfaces of the outer segment  5 , as with the converter box  3 , end caps  6   a  and  6   b  are also provided. The front cover plate  6   a  analogue to the converter box  3  can be seen to also have two stampable window openings. The window openings, however, in contrast to the two window openings  9  in the converter box  2  are sealed with the exception of a single small plug opening for the connection to the converter box  3  in the left window. The rear end cap  6   b , as its counterpart in the converter box  3 , has a continuous, closed mounting plate  8 . 
     As with the converter box  3 , the two outer segments  5  and the central segment  4  of the accumulator box  17  consist of a U-shaped frame construction, the structure of which was already described. The lateral surface  11  of the outer segment  5  directed forwards, as with the converter box  3 , also has an opening  13 , which is, however, sealed by a plate  14 . The rear lateral surface  11  of the two outer segments  5  has a further opening  18  for the air conditioning of the accumulator cabinet  17 . The central segment  4  of the accumulator cabinet is identical to that of the converter box  3 . 
     For the production of both the accumulator box  17  as well as the converter box  3 , only one U-shaped segment part, and in each case end caps  6   a  and  6   b  and a cover  1 , are required. With these two modular components  20 , different switchgear cabinet arrangements can thus be implemented. If for example a larger converter is required for another application, a larger central segment is used. 
     For the construction of the switchgear cabinets, shorter delivery times thus result due to identical parts frequently being present. 
       FIG. 5  shows a schematic representation of the modular system  21  already described above with assignable modular components  22  for the production of a modular switchgear cabinet. With the few modules and segments shown in  FIG. 5 , different switchgear cabinets or switchgear cabinet arrangements can be implemented as required and according to function. The functions can form a corresponding arrangement of the modular components. 
     A narrow U-shaped segment or module  19  and a wide U-shaped segment or module  20  are shown in the top left of  FIG. 5  as first basic modular components. The shorter segment  20  is identical in its basic structure to the outer segment  5  in the application as accumulator box  17  or as converter box  3 , and the wider segment  20  is identical to the central segment  4 . The lateral surfaces of the basic modular component are configured as an auxiliary element, a special element, an adapting element or as a non modular component, like for example the plug panel  7 , the window openings  9  and  13 , or the plate  14 . As can further be seen from  FIG. 5 , the spatial arrangement of the two basic modular components  19  and  20  can also be interchanged, i.e. the modular component designated as central segment  4  in the accumulator box can also be arranged at the edge. Furthermore, a modular component designated as outer segment in the converter box can take up a central position. 
     The two end caps  6   a  and  6   b  can also be seen from  FIG. 5  as a further basic modular component. Each cap consists of a plate which is in each case, as required and according to function, also configured as auxiliary element, special element, adapting element or as non modular component. 
     A switchgear cabinet  2 , which functions as a master control cabinet or master control box in the hub or in the gondola, can be assembled from a combination of two short U-shaped segments or two basic modular components  19  according to  FIG. 5 . The latter in turn correspond to two outer segments  5  of a converter box  3 . By virtue of a modular arrangement with only few partial segments or modules, different customer specifications can thus be presented with one and the same modular system.