DESC:FIELD
The present disclosure relates to the field of derrick structure for replacement of a generator of a wind turbine.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Generally, a wind turbine includes a tower, a nacelle, and a blade which is coupled to the front end of the nacelle and electricity generation system. The electricity generation system comprises a gearbox, an electric generator and a transformer. A wind turbine generator system is mechanically coupled to wind driven rotors that utilizes wind to produce electricity. The wind turbine generator is disposed inside a nacelle, and is subject to various environmental conditions such as lightning strikes, wind loading, weather extremes, lubricant contamination, thermal cycling, etc. which leads to failure of the generators and its components. Due to failure, the generator and its faulty components need to be replaced.
Conventionally, cranes are required to raise and lower the faulty components that are heavy and bulky, from the nacelle to ground. However, the use of crane is not feasible when wind turbine is located in remote locations that are difficult to access.
There is, therefore, felt a need of a structure for replacement of the generator of a wind turbine that alleviates the above-mentioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a derrick structure for replacement of a generator of a wind turbine.
Another object of the present disclosure is to provide a derrick structure that has simple design.
Yet another object of the present disclosure is to provide a derrick structure that consumes less time for replacement of a generator of a nacelle.
Still yet another object of the present disclosure is to provide a derrick structure that is portable.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a derrick structure for replacement of a generator of a wind turbine configured to be fitted in a nacelle of the wind turbine. The derrick structure includes a plurality of leg posts in front and rear side adapted to be fitted on a nacelle chassis. The plurality of cross beams mounted on top of the leg posts. At least one monorails configured longitudinally between a front cross beam and a rear cross beam. At least one first pulley provided on the monorail near the operative front end and least one second pulley provided in the central portion of the monorail. A removable lifting jig configured attached on top of the generator and configured for supporting the weight of the generator during lifting and installation. An I-beam lifting trolley connected to the monorail. The I-beam lifting trolley configured to slide along the length of the monorail. At least one third pulley connected at the central portion of the lifting jig. A rope running parallel to the base of turbine passing over the first pulley then passing over the central pulley and then returning back after passing over the third pulley such as to lift the generator to facilitate the movement of the generator in a lifted condition in the front and back direction to adjust the position of the generator on the nacelle during maintenance and installation.
In an embodiment the wire rope is connected to a load supporting mechanism such as a hoist.
In another embodiment a rectangular block having a lifting stud to be held with a thread block connected to one end of the I-beam lifting trolley.
In still another embodiment a bottom pulley mounted on a tower bottom jig and the bottom pulley coupled to a load supporting mechanism via a wire rope.
In an embodiment the leg posts consists of a set of front leg posts , a front right side leg post, a front left side leg post, a rear post left hand side, and a rear post right hand side.
In another embodiment the pulleys consists of a first pulley connected to the front side of the monorail and a second pulley connected to the rear side of the monorail via studs and nuts.
In still another embodiment the lifting jig includes a plurality of beams, a lifting jig beam LH and a lifting jig beam RH horizontally disposed above the generator.
In an embodiment the lifting jig includes a holder and a hook .The holder configured to hold the generator thereof and the hook configured to couple the holder with the third pulley.
In another embodiment the lifting jig connected between a lifting jig side plate front and a lifting jig side plate back, wherein the second pulley of the monorail in vertical axis of the third pulley.

In an embodiment the structure includes a steel rafters assembled in between the flanges of front right leg post and the flanges of rear right leg post such that the generator can be moved laterally in a position suitable to facilitate lowering of the generator on the ground.
The method for replacement of a generator of a wind turbine from the derrick structure, the method includes:
• fixing a load supporting mechanism on the ground in the vicinity of the wind turbine;
• fitting a plurality of leg posts on a nacelle chassis;
• fitting a front cross beams and a rear cross beam on the top of the leg posts;
• fitting at least one monorails longitudinally between a front cross beam and a rear cross beam;
• mounting first pulley on the monorail near the operative front end and second pulley in the central portion of the monorail;
• fitting an I-beam lifting trolley to the monorail;
• mounting third pulley at the central portion of a lifting jig;
• fixing the generator on the lifting jig; and
• actuating the load supporting mechanism for drawing in the wire rope and lifting the generator from the ground level up to the nacelle chassis and drawing out the wire rope for lowering the generator from the nacelle chassis to the ground level.
In another embodiment the generator is lifted from a nacelle cross frame and then moved towards the right-hand side of the nacelle up to a position suitable to facilitate lowering of said generator (32) on the ground.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The derrick structure of the present disclosure for replacement of a generator of a wind turbine will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a side view of a simplified structure mounted in nacelle chassis according to the present invention;
Figure 2 illustrates a side view of the derrick structure used for lowering the generator of Figure 1;
Figure 3 illustrates a side view of generator being lowered with the help of manual force and load supporting mechanism, in accordance with an embodiment of the present disclosure;
Figure 4 illustrates a side view of a bottom pulley coupled with a load supporting mechanism via a lifting line, in accordance with an embodiment of the present disclosure;
Figure 5 illustrates a side view of the derrick structure securely connected to the nacelle chassis of Figure 1, in accordance with an embodiment of the present disclosure;
Figure 6 illustrates an isometric view of the complete structure assembly in an installed position at the nacelle frame, in accordance with an embodiment of the present disclosure;
Figure 7 illustrates an isometric view of the complete structure assembly in an installed position at the nacelle frame, in accordance with another embodiment of the present disclosure;
Figures 8 illustrates a side view of the derrick structure securely connected to the nacelle frame of Figure 7, in accordance with an embodiment of the present disclosure;
Figure 9 illustrates a front view of a lifting stud, in accordance with an embodiment of the present disclosure;
Figure 10 illustrates a side view of the derrick structure securely connected to the nacelle chassis, in accordance with an embodiment of the present disclosure;
Figure 11 illustrates an isometric view of the derrick structure assembly in an installed position at the nacelle frame, in accordance with another embodiment of the present disclosure;
Figure 12 illustrates a back view of a derrick structure assembly in nacelle frame of Figure 11, in accordance with an embodiment of the present disclosure;
Figure 13 illustrates an isometric view of the derrick structure assembly in an installed position at the nacelle frame, in accordance with another embodiment of the present disclosure; and
Figure 14 illustrates a side view of the derrick structure securely connected to the nacelle chassis of Figure 13, in accordance with an embodiment of the present disclosure.
LIST OF REFERENCE NUMERALS USED IN DETAILED DESCRIPTION AND DRAWING
100 – Structure
21 – Nacelle
24 – Nacelle chassis
24A – Nacelle cross frame
25 - L Plate stool
25A - Front left side L-Plate stool
25B - Front right side L-Plate stool
25C - Rear left side L-Plate stool
25D - Rear right side L-Plate stool
26 - Counter support stool
27 - Bolted left-hand side beam
28 - Bolted right-hand side beam
29 - Front side bottom cross beam
30 - Rear side bottom cross beam
32 – Generator
33 – Hooks
37 – Stud/Pin
37A – Nut for joint
38 - Top left-hand side beam
39 - Top right-hand side beam
40 – Bottom Pulley
41 – First Pulley
41A – Second Pulley
42 – Third Pulley
43 – Lifting line/ Wire Rope
44 – Traction Hoist
45 – Tower bottom Jig
46 – Set of Front leg Posts
46A – Front Left side leg post
46B – Front Right side leg post
47 – Rear Post Left Hand Side
47A – Rear Post Right Hand Side
48 – Bottom Stool Left Hand Side
48A – Bottom Stool Right Hand Side
49 – Base Plate
50 – Wedge Plate
51 – Gusset Plate
52 – Side Plate
53 – Front Cross beam
54 – Rear Cross beam
55 – Monorail
56A – Side support - 1
56B – Side support - 2
57A – Side support - 3
57B – Side support - 4
57C – Side support - 5
57D – Side support - 6
57E – Side support - 7
58 – Lifting Jig
58A - Lifting Jig-1
59A – Lifting jig beam -LH
59B – Lifting Jig beam - RH
60A – Lifting jig side plates - Front
60B – Lifting jig side plates – Back
61 – Manual Force/Operator
62 – Tag Line
65 – Load Supporting Mechanism
67 – I-Beam Geared Trolley
67A – I-Beam Lifting Trolley
68 – Rectangular Block
69 – Lifting Stud
70 – Thread Block
71- Wheel
72 – Cross strut -1
73 – Cross strut -2
74 – Steel rafter -1
75 – Steel rafter -2
76 – Tie beam-1
77 – Tie beam-2
78 – Tie beam-3
79 – Tie beam-4
80 – Tie post -1
81 - Tie post -2
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
When an element is referred to as being “mounted on”, “adapted to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed elements.
Terms such as “front”, “back”, “beneath”, “up”, “down”, “above”, “upper” and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
The present disclosure envisages a derrick structure for replacing a generator within a nacelle. The derrick structure (hereinafter referred to as “structure 100”) is described herein below with reference to Figure 1 to Figure 14.
Referring to Figure 1 and Figure 2 depicts a side view of a derrick structure (100) configured to be fitted in the nacelle (21) of the wind turbine. The derrick structure (100) includes a plurality of leg posts (46, 47), a front cross beams (53), a rear cross beam (54) cross beam, at least one monorails (55), a set of pulleys, a removable lifting jig (58) and an I-beam lifting trolley (67A). The leg posts consists of a set of front leg posts (46), a front left side leg post (46A), a front right side leg post (46B), a rear post left hand side (47), and a rear post right hand side (47A).
The rear post left hand side (47) and the rear post right hand side (47A) are secured to the chassis (24). The rear post left hand side (47) and the rear post right hand side (47A) are secured via the base plate (49) placed on an operative top portion and bottom portion of the chassis (24) and the wedge plate (50) with studs (37) and nuts (37A).
In an embodiment, as shown in Figure 3, the generator (32) is de-erected from the nacelle (21) by using load supporting mechanism (65) and tag line (62) held by manual force (61) with the support of derrick structure (100).
In another embodiment a bottom pulley (40) is mounted on a tower bottom jig (45). Referring to Figure 4, the bottom pulley (40) is coupled to the load supporting mechanism (65) via the wire rope (43). A wire rope (43) paves out of one or more load supporting mechanism (65) and passes through the bottom pulley (40) to the first pulley (41) connected at front side of the monorail (55) and then to the second pulley (41A) at rear side of the monorail (55) and then towards the third pulley (42) and again back to the second pulley (41A), thereby forming a gun tackle arrangement. The end point of the wire rope (43) is clamped at the second pulley (41A). The gun tackle arrangement gives a mechanical advantage of amplifying the force applied to the rope (43) and the selection of rope lines (43) based on the load. The mechanical advantage of the gun tackle arrangement can be increased by interchanging the fixed and moving blocks so that the rope (43) is attached to the moving block and the rope (43) is pulled in the direction of the lifted load such as re-erection of the generator (32) or raising the generator (32) from the ground. The force in the wire rope (43) is controlled by a winch (65). The load supporting mechanism is a winch (65).
Referring to Figure 5 to Figure 6, the front cross beam (53) is connected on top of each of the front left side leg post (46A) and the front right side leg post (46B) via a plurality of studs/pins (37) and nuts (37A). Similarly, the rear cross beam (54) is connected on top of each of the rear post left hand side (47) and the rear post right hand side (47A) via a plurality of studs (37) and nuts (37A). Further, the monorail (55) is horizontally connected on top of the cross beams (53, 54) via a plurality of studs (37) and nuts (37A). Further, the first pulley (41) is connected to the front side of the monorail (55) and a second pulley (41A) is connected to the rear side of the monorail (55) via studs (37) and nuts (37A) to securely hold the first pulley (41) and the second pulley (41A) in between the monorail (55).
In an embodiment, the derrick structure (100) includes the two monorails (55) parallely crossing over between the front cross beam (53) and rear cross beam (54), and the third pulley (42) directly connected to the lifting jig (58) to lift and lower the generator (32) by the wire rope (43) of the load supporting mechanism (65).
The third pulley (42) connected at the central portion of said lifting jig (58) and a rope (43) running parallel to the base of turbine passing over the first pulley (41) then passing over the central pulley (41A) and then returning back after passing over the third pulley (42) such as to lift the generator (32) to facilitate the movement of the generator in a lifted condition in the front and back direction to adjust the position of the generator (32) on the nacelle during maintenance and installation.
In order to re-erect or de-erect a component of the nacelle (21) such as the generator (32), the lifting jig (58) is attached over the generator (32). The lifting jig (58) has two beams i.e. a lifting jig beam LH (59A) and a lifting jig beam RH (59B) are in horizontally disposed above the generator (32). Further, the lifting jig (58) has side plates i.e. a lifting jig side plate front (60A) and a lifting jig side plate back (60B) that are connected at operative ends thereon. The lifting jig side plate front (60A) and lifting jig side plate back (60B) are in turn connected to the hooks (33) of the generator (32), as depicted in Figure 5. The lifting jig (58) also has a third pulley (42) which is connected in between the lifting jig side plate front (60A) and lifting jig side plate back (60B) such that the second pulley (41A) of the monorail (55) is in vertical axis of the third pulley (42). In an embodiment, the third pulley (42) is a set of movable pulleys.
In another embodiment, referring to Figure 7 to Figure 9 the derrick structure (100) includes the load carrying I-beam trolley (67) is used for lowering the generator (32) which is fixed on a nacelle cross frame (24A) whose position may be away from the center axis to the monorail (55) lifting pulleys said as second pulley (41A) and third pulley (42) in vertical direction. Therefore, it is essential to assemble the second pulley (41A) and the third pulley (42) and the wire rope (43) in position which is perpendicular to the monorail (55). The operation of the winch (65) may further lift the generator (32) from the nacelle frame (24A). Further the wrench or spanner is used to fix the studs (69), the generator (32) is now lifted to the specified height and now the load is transferred from I-beam trolley (67) to winch rope (43). In order to that, pulling the hand chain operates to move I-beam trolley (67) in front direction, accordingly the third pulley (42) moves manually in required position to the front side of the monorail (55). The winch (65) controls tension in the wire rope (43) passing through the third pulley (42), then to the lifting jig (58) attached to the generator (32), subsequently the load i.e. the generator (32) can be transferred from I-beam trolley (67). Further, the stud (37) can be removed to remove the I-beam trolley (67) from the monorail (55) and the lifting stud (69) is held with thread block (70) which may be removed after the load i.e. the generator (32) is completely lowered to ground .
The side support-1 (56A) and the side support-2 (56B) are connected in cross manner between the front leg post (46) and the rear post left hand side (47). The gusset plate (51) is welded to the front leg post (46) and the rear post left hand side (47), and the operative ends of the side support-1 (56A) and the side support-2 (56B) side is connected to the gusset plate (51). Similarly, the side support-3 (57A) and the side support-4 (57B) are connected in cross manner between the front leg post (46) and the rear post right hand side (47A). Each of the side support-3 (57A) and the side support-4 (57B) is welded at respective ends via the gusset plate (51) and via a plurality of studs (37) and nuts (37A). Each of the side support-1 (56A) and the side support-2 (56B) is connected to the gusset plate (51) via the plurality of studs (37) and nuts (37A).
The purpose of this trolley (67A) allows the load to travel along the direction of the lifting beam. The geared trolleys (67) consist of a looped hand chain, which is connected to a sprocket. The sprocket engages the gears which facilitates movement of the wheel (71) when the operator (61) pulls the hand chain. Gear travel units are moved along the beam by operating a hand chain. This suits a variety of I-beam widths to provide an easy and convenient means to allow moving of the trolley (67) along with the generator (32) in front or back position. This also consist of bottom hook, hand wheel, hand chain, geared wheel, track wheel, side plate (52), suspension shaft, pin, pinion, sprocket, axis rod or stud, etc. In this process the generator (32) is attached by the lifting jig (58) via a bottom hook of I-beam geared trolley (67) to move front or back in upright position.
The I-beam trolleys (67) are also referred to as hand geared trolleys that incorporate a looped hand chain, which is attached to a hand chain wheel (not shown in figures) or sprocket (not shown in figures). When the operator (61) pulls the hand chain, the sprocket then engages the gears which facilitate wheel (71) movement. Upon pulling the chain, the I-beam trolley (67) will travel in the opposite direction. Gear travel units (not shown in figures) are moved along the monorail (55) by operating a hand chain which facilitates operator (61) a greater level of control especially on larger capacities. In an embodiment, the monorail (55) end has gusset plates (51) designed such that ensures extra safety, and also prevents damage to the wheels (71) when contacting end rail stoppers said as gusset plates (51).
Further, an alternate arrangement can be used i.e. I-beam lifting trolley (67A) as shown in Figure 8, to allow the generator (32) to move either up/down and/or front or back to adjust the position and height of the generator (32) while lowering the generator (32) from the nacelle cross frame (24A). The purpose of this trolley (67A) is that it allows the load i.e. generator (32) to move up and down with horizontal traversing along the direction of the lifting beam when the operator pulls the hand chain. This consists of lifting stud (69), thread block, welded nut, hand chain, hand wheel, side plates (52), track wheel, chain and pins. By using the spanner to adjust or screwing the lifting stud (69) to adjust move up and down along load with generator (32) and further requires traverse position (front or back) and hold it. Then the generator (32) is shifted to third pulley (42) which means moving pulley for further preparation of generator (32) erections. Here the lifting stud (69) is connected to the rectangular block (68), it may further extended and held with thread block ends with lifting jig (58). The rectangular block (68) is connected with side plate (52). All other functions are remains similar as the aforementioned I-beam geared trolley (67).
The I-beam trolley (67) mechanism have two pairs of wheels adapted to engage the monorail (55) which allows the load i.e. generator (32) to travel along the direction of the monorail (55). Further, each one of these wheels (71) being supported on an axis-rod or stud (37), which is mounted with side plate (52) and then the rectangular block (68) is dropped. The rectangular block (68) is extended along with the lifting stud (69) and may be suspended and is then finally held with the thread block (70).
In an embodiment, one end of the I-beam trolley (67) is the thread block (70) which is adapted with lifting jig (58) in two positions from the center axis. The lifting stud (69) has one end with a welded nut (37A) and the other end with a thread block (70). In an embodiment, the length of the lifting studs (69) can be adjusted by screwing the stud (69) in or out.
In an embodiment, the system of monorail (55), and cross support i.e. the manner in which the side support-1 (56A) and the side support-2 (56B), and the side support-3 (57A) and the side support-4 (57B) are connected is different manner. Further, the shape of the lifting jig (58) also changes with respect to the shape of the generator (32) being lowered.
In another embodiment of Figure.10, matching the front right side L-plate stool (25B) and rear right side L-plate stool (25D) on the nacelle bed on desired location by means of the holes provided over on the right side of the generator when viewing from the nacelle rear location with rotor at its front. Similarly, the front left side L-plate stool (25A) and rear left side L-plate stool (25C) are assembled on the desired location of the left side of the nacelle bed.
In order to that, assemble the counter support stool (26) behind the rear right side L-plate stool (25D). This counter support stool (26) has inclined profile to match the rear side of the nacelle as well as it will provide the flat support to the parts which will assemble over it. Further, the bolted right-hand side beam (28) have place over the counter support stool (26), rear right side L-plate stool (25D) and front right-side L-plate stool (25B) and assembled these parts together with the bolt connection through the holes provision that provided on the side L-plates and beam. Concurrently, the bolted left-hand side beam (27) is assembled over the rear and front left side L-plate stool (25) by means of matching their holes. This side beam is constructed with I-beam, flanges at its top and has at least one side extension plate to match with the right-side beam (28).
In same embodiment, front right-side leg post (46b) is assembled over the front flange of the bolted right-hand side beam (28) by means of matching the holes provision on the leg post. This leg post is fabricated with two C-channels which forms a square profile and they have at least one square flanges along their length and at its both ends, and also have rectangular plate as flanges are welded adjacent to the square flanges. In order to that, assemble the rear right side leg post (47a) over the rear side of the bolted right-hand side beam (28). This rear right side leg post (47A) is similar in construction of the front right-side leg post (46b) but may vary in geometry. Further to that, the front side bottom cross beam (29) and rear side bottom cross beam (30) have assembled between the side extensions of the bolted left-hand side beam (27) and bolted right-hand side beam (28). All these side leg posts are fabricated with c-channels welded together which forms a square profile and they have flanges attached to it both ends and along its length.
In embodiment of Figure.11, assemble the top left-hand side beam (38) over the front and rear left side leg post by means of matching the flanges with the holes provision. This top left-hand side beam also consists of flanges at both of its ends and at least one flange attached to its bottom side with the support of at least one rib provided across the length of this side beam to ensure the strength of the component. Followed by, the top right-hand side beam (39) is assembled over the front and rear right side leg post by means of matching the flanges with the holes provision. The top right-side beam has at least one flange at its top side of the web and two flanges at bottom side of the web. Though these flanges at the top will match in line with the top flanges of the top left side beam and the bottom flange is used to assemble the monorail (55). Both this top left and right-side beam are fabricated with I-section beams and plates are provided along its flange sides to make it robust for bending load.
In another embodiment, the side support – 3 (57A) is a C-channel component with holes provision on both ends used for assemble by means of bolted connection in between the extension plates of the rear left side leg post (47) and rear right side leg post (47A) at the bottom portion. Simultaneously, assemble the side support – 5 (57C) near the top portion and the side support – 4 (57B) is assembled between the side support – (3) and side support – (5) diagonally. Followed by, the side support- (1) 56A and side support – (2) 56B are assembled in between the front left side leg post46a and rear left side leg post (47) in the cross pattern. Then, the side support – 7 (57E) is used to assemble in between the front and rear left side leg post at the bottom portion just below the contact point of the side support-(1) and side support-(2) with the extension plates provided on the leg post. Then, the side support – 6 (57D) is assembled in between the extension plates of the front left and right-side leg post by fastening unit. All these side support parts are c-channels with holes provision at its ends to match with the adjacent parts by fastening units (37) & (37A).
In yet another embodiment, assemble the front cross beam (53) and rear cross beam (54) by means of fastening the flanges on the top portion of the top left-hand side beam (38) and right-hand side beam (39). By this manner, the front and rear cross beams are assembled with parallel to each other. Both of these cross beams are fabricated with square profiles and flanges are welded along its length on desired locations. Followed by, assemble the monorail (55) by means of matching the bottom flanges of the top left- and right-hand side beam. Assemble the cross strut –1 (72) with the flanges of the front cross beam (53) and rear cross beam (54) by means of matching the holes provision that provided on the flanges along the length of the cross strut – 1 (72) which also has flanges attached to inclined angle at both of its end while another flange is set to assemble with the monorail by fastening unit. Further in the same line, assemble the cross strut – 2 (73) over the flange that provided over the monorail (55) in order to make the monorail as more strength against the bending load.
A steel rafter – 1 (75) and steel rafter – 2 (74) are assemble in between the flanges of front right leg post 46b to cross strut – 1 (72) and the flanges of rear right leg post 47a at cross strut – 1 (72) respectively. These steel rafters are fabricated with square profile and at least have one flange along its length to make a fastening joint with the front and rear right leg post to arrest the bending load. Then, assemble the tie beam – (3) 78 and tie beam – (4) 79 in between the rear right leg post and the steel rafter – 2 while the tie beam – 4 lies in bottom portion and tie beam – 3 lies just above the tie beam- 4. Similarly, the tie beam – (1) 76 and tie beam – (2) 77 are assembled on the right front side and secure the connection by fastening the flanges with fastening units. After ensuring all the fastener connections, the tie post – (1) 80 and tie post – (2) 81 are assemble in between the flanges of the front right leg post (46B) to top right-hand side beam (39) and rear right leg post (47A) to top right-hand side beam (39) respectively.
After the completion of the structure parts assembly in over the nacelle frame (24A), the tower bottom jig (45) is set to assemble over the bottom of the tower in which the bottom pulley (40) is assembled. By which, the bottom pulley locates in line with the left end portion of the monorail in which the first pulley (41) is assembled. According to the Figure.12 followed by, assemble a set of trolley (67) over the monorail and using these trolleys the second pulley with three sheaves is mounted in between them. So, there will be no relative motion between these trolleys while moving it by hand operation or through the chain wheel operation. Then, the lifting jig (58) is assembled with the hooks (33) of the generator (32) through the connecting mechanism and ensures the connections are secured before proceed the lifting process. Finally, introduce the third pulley (42) which has two sheaves over the provision of the lifting jig (58).
Then the lifting line (43) from the load bearing mechanism (65) is set to pass through the bottom pulley (40) and first pulley (41) and then to the sheaves of the second pulley (41A). Thereafter, the lifting line (43) is locked with the moving pulley (42) after passing through its sheaves. After ensuring the position of the lifting line in all aspects, the load bearing mechanism (65) is start to draw up the lifting line which results in lifting of the generator (32) to a desired position from its location in the nacelle (21). Then the U-bolts or locking clamp are used to lock the sliding motion of the lifting line (43) in the second pulley (41A) which results no vertical movement of the generator (32) from the point it is set to be fixed. Then slowly slacken the load bearing mechanism (65) and in concert the I-beam geared trolleys (67) are moved from its position through the hand operation or chain wheel operating mechanism. This simultaneous operation makes the generator to step out of the nacelle on its right side without changing the height at which it kept in position. Once, the generator reaches the extreme right portion of the monorail (55) the U-bolts or locking clamp are set to release then the generator (32) is set to lowering. By this the lifting line experiences a tension and by maintaining the tension the load bearing mechanism (65) is release the lifting line (43) which results the relative motion between generators (32) with the lifting line motion. Through this, the generator (32) is release from the top of the nacelle to the ground with the help of guiding the tag lines to ensure the safe erection. The raising the generator is same as to reversible process of lowering the generator (32) from wind turbine nacelle.
In an embodiment Figure.13, fix the front right bottom stool (25B) and rear right bottom stool (25D) on the nacelle bed on desired location by means of the holes provision that provided over it on the right side of the generator position when viewing from the nacelle rear location with rotor at its front. These bottom stools have two plates that are welded together with a square profile to form a single component with at least one vertical rib and also the top face of the stools have holes provision to match with adjacent parts. Followed by, the Front Left side leg post (46A) and rear left side leg post (47) is assembled over the nacelle bed at desired position on the left side of the generator position. Both of these side leg posts are fabricated with c-channels welded together which forms a square profile and they have flanges attached to it both ends and along its length. Then, assemble the counter support stool (26) behind the rear right bottom stool (25D). This counter support stool which acts as a wedge, has inclined profile to match the rear side of the nacelle as well as it will provide the flat support to the parts which will assemble over it. Later, the bolted right-hand side beam (28) placed over the counter support, rear right bottom stool (25D) and front right bottom stool (25B) and assembled these parts together with the bolt connection through the holes provision that provided on the bottom stools and beam. This right-hand side beam is a component which has I-beam welded with plates on its flange sides to make it more robust and harder to bend also, the ends of this beam have welded with flanges which have holes provision to match with the adjacent parts.
In another embodiment, front right-side leg post (46B) is assembled over the front flange of the bolted right-hand side beam (28) by means of matching the holes provision on the leg post. This leg post is fabricated with two C-channels which forms a square profile and they have at least one square flanges along their length and at its both ends. Also have rectangular plate as flanges are welded adjacent to the square flanges. Concurrently, assemble the rear right side leg post (47A) over the rear side of the bolted right-hand side beam (28). This rear right side leg post (47A) is similar in construction of the front right-side leg post (46B) but may vary in geometry.
In yet another embodiment Figure.14, the side support-(1) 56A and side support –(2)56B are assembled in between the rear Left side leg post (47) and rear right side leg post (47a) in the cross pattern by means of connecting the one end of the side support –(1) to the extension plate at the top of the rear right side leg post (47A) and other end of side support –(1) is used to connect with the extension plate at the bottom portion of the rear left side leg post (47). Similarly, the side support – (2)56B is connect in between rear left and right-side leg post to form a cross pattern in between them. Concurrently, the side support – (5) 57C and side support – (6)57D is assembled in between the front left and right-side leg post in the cross pattern. Likewise, the side support – (3)57A and side support – (4)57B is assembled in between the front and rear left side leg post in the form of cross pattern. All these side supports are a C-channel component with holes provision on both ends used for assembles by means of bolted connection in between the extension plates of the side leg posts.
Referring to the Figure 13 and Figure 14 the front right bottom stool (25B), rear right bottom stool (25D), front Left side leg post (46A) and rear left side leg post (47) are attached to the holes provided in the nacelle frame (24).
In another embodiment absence of the holes in the nacelle frame (24), then the base plate (49) is placed below the nacelle frame (24) in the same direction to connect the stud (37) and nuts (37A) matching with the flanges of front right bottom stool (25B), rear right bottom stool (25D), front Left side leg post (46A) and rear left side leg post (47) placing above the nacelle frame (24).
In an embodiment, assemble the top left-hand side beam (38) over the front and rear left side leg post by means of matching the flanges with the holes provision. This top left-hand side beam also consists of flanges at both of its ends and at least one flange attached to its bottom side with the support of at least one rib provided across the length of this side beam to ensure the strength of the component. Followed by, the top right-hand side beam (39) is assembled over the front and rear right side leg post by means of matching the flanges with the holes provision. This top right-side beam (39) has at least one flange at its top side of the web and two flanges at bottom side of the web. Though these flanges at the top will match in line with the top flanges of the top left side beam (38) and the bottom flange is used to assemble the monorail (55). Both this top left and right-side beam are fabricated with I-section beams and plates are provided along its flange sides to make it robust for bending load. In order to arrest the tilting motion between the top right-hand side beam (39) and the front right leg post (46B) & rear right leg post (47A), the tie post – (1)80 and tie post – (2)81 are introduced in between them and these tie posts are assemble in between the flanges of the front right leg post (46B) to top right-hand side beam (39) and rear right leg post (47A) to top right-hand side beam (39) respectively. Followed by, assemble the monorail (55) by means of matching the bottom flanges of the top left- and right-hand side beam while the first pulley extension is face towards the left-hand side. This monorail (55) is fabricated components of I-beam with additional plates are welded at both of it ends to acts as a stopper and at least one flange is welded over the top web along its length. In addition to that, they have at least one extension plates at the extreme end and another one after some interval. These extension plates of the monorail (55) are used to provide support to the first pulley (41) and second pulley (41A). Followed by, assemble the cross strut – (1) 72 over the monorail (55) by assembling the flanges with the fastening units. This cross strut – (1) 72 is a fabricated I-beam with square flanges along its length to provide support to adjacent parts.
According to the above embodiment, the steel rafter – (1)74 and steel rafter – (2)75 are assemble in between the flanges of front right leg post 46B to cross strut – (1)72 and the flanges of rear right leg post (47A) at cross strut – (1)72 respectively. These steel rafters are fabricated with at least have one flange along its length to make a fastening joint with the front and rear right leg post to arrest the bending load. Then, assemble the tie beam – (1)76 and tie beam – (2)77 in between the front & rear right leg post and the steel rafter – (1) 74 and steel rafter – (2) 75 respectively and secure the connection by fastening the flanges with fastening units. Followed by, assemble the cross strut – (2)73 over the monorail by following the same manner as what followed in cross strut – (1) 72 assembly. After the assembly of this cross strut – (2) 73, the flanges on this cross strut will lie in line with the flanges with the cross struct – (1) 72 and the top right-hand side beam (39) with this symmetry, the front cross beam (53) and rear cross beam (54) are assemble by matching these flanges while the front cross beam connects the right side portion of the cross strut – (1) 72, cross strut – (2) 73 and then the top right hand side beam (39) and the rear cross beam (54) connects the same like in rear portion.
After the completion of the structure assembly, the tower bottom jig (45) is set to assemble over the bottom of the tower in which the bottom pulley (40) is assembled. By which, the bottom pulley locates in line with the left portion of the monorail (55) in which the first pulley (41) is assembled. Followed by, assemble at least a set of I-beam geared trolley (67) over the monorail (55) and the second pulley (41a) with three sheaves is mounted in between the extension plates of the monorail (55). Then, the lifting jig (58) is assembled with the hooks (33) of the generator (32) top portion through the connecting mechanism and the connections is same followed in lifting jig-1 (58A) in bottom portion of the generator. Finally, introduce the third pulley (42) which has two sheaves over the provision of the lifting jig (58).
Then introduce the lifting jig-1(58A) in the bottom portion of the generator (32) and use the holding mechanism like chain hoist instead of lifting stud (69) attached to the I-beam trolley (67) which connects this lifting jig – 1 58A as shown in Figure.14. Followed by, the lifting line (43) from the load bearing mechanism (65) is set to pass through the bottom pulley (40) and first pulley (41) and then to the sheaves of the second pulley (41A). Thereafter, the lifting line (43) is locked with the moving pulley or third pulley (42) after passing through its sheaves. In relates of the second pulley and third pulley in the formation of gun tackle arrangement. Using the holding mechanism like chain block attached from the trolley (67), the generator (32) is lift from its position in the nacelle to the desired height. Meanwhile, the third pulley (42) which is set to mount over the lifting jig (58) is slightly slackened due to change of generator position. Once the generator reached the extreme right position that is out of the nacelle, the load bearing mechanism (65) starts to draw up the lifting line (43) which results in lifting of the generator to a desired position from its previous location which in turn results the holding mechanism to experience the less load. After ensuring the position of the lifting line in all aspects, the load bearing mechanism (65) is start to draw up the lifting line (43) which results in lifting of the generator (32) to a desired position from its previous location. Once the load bearing mechanism (65) experience the full load of the generator (32) through the lifting line (43), the lifting line will tighten the load will results in slackening the holding mechanism from which we disengage the holding mechanism with the trolley (67) from the lifting jig – 1 (58A) of the generator (32) and the trolleys (67) are moved back in to the nacelle (21). At such instance, the entire weight of the generator (32) is carried by the load bearing mechanism (65). By this the lifting line experiences a tension and by maintaining the tension the load bearing mechanism (65) is release the lifting line which results the relative motion between generators with the lifting line motion. Through this, the generator is release from the top of the nacelle to the ground with the help of tag lines (62) and manual support (61) for safe erection. The re-erection of the generator (32) from the surface to the nacelle (21) is reverse process of the generator de-erection from the turbine.
The method for replacement of a generator of a wind turbine from the derrick structure (100), the method includes:
• fixing a load supporting mechanism (65) on the ground in the vicinity of the wind turbine;
• fitting a plurality of leg posts on a nacelle chassis (24);
• fitting a front cross beam (53) and a rear cross beam (54) on the top of the leg posts (46, 47);
• fitting at least one monorails (55) longitudinally between a front cross beam (53) and a rear cross beam (54);
• mounting first pulley (41) on the monorail (55) near the operative front end and second pulley (41A) in the central portion of the monorail (55);
• fitting an I-beam lifting trolley (67A) to the monorail (55);
• mounting third pulley (42) at the central portion of a lifting jig (58);
• fixing the generator on the lifting jig (58); and
• actuating the load supporting mechanism (65) for drawing in the wire rope (43) and lifting the generator (32) from the ground level up to the nacelle chassis (24) and drawing out the wire rope (43) for lowering the generator (32) from the nacelle chassis (24) to the ground level.
In an embodiment, the derrick structure (100) is included with the structure like pin type, flange type and stool type which are used for fixing the front post and rear post. This construction is based on nacelle frame designed as per various manufacturers along with or without anchorage point.
The derrick structure (100) is simple, portable, and can be transported to an installation area by a small truck. Further, the structure (100) facilitates shortening of installation time of the component.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a derrick structure for replacement of a generator of a wind turbine that:
• consumes less time for replacement of a generator of a nacelle;
• has simple design; and
• is portable.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A derrick structure (100) for replacement of a generator (32) of a wind turbine, said structure (100) configured to be fitted in the nacelle (21) of the wind turbine and comprising:
• a plurality of leg posts (46, 47) in front and rear side, said leg posts adapted to be fitted on a nacelle chassis (24);
• a front cross beams (53) and a rear cross beam(54) mounted on the top of said leg posts (46, 47);
• at least one monorails (55) configured longitudinally between a front cross beam (53) and a rear cross beam (54);
• at least one first pulley (41) provided on said monorail (55) near the operative front end and least one second pulley (41A) provided in the central portion of said monorail (55);
• an I-beam lifting trolley (67A) connected to said monorail (55), said I-beam lifting trolley (67A) configured to slide along the length of the monorail (55) ;
• a removable lifting jig (58) configured attached on top of said generator (32) and configured for supporting the weight of said generator (32) during lifting and installation; and
• at least one third pulley (42) connected at the central portion of said lifting jig (58) ,
a rope (43) running parallel to the base of turbine passing over the first pulley (41) then passing over the central pulley (41A) and then returning back after passing over the third pulley (42) such as to lift said generator (32) to facilitate the movement of said generator in a lifted condition in the front and back direction to adjust the position of the generator (32) on the nacelle during maintenance and installation.
2. The derrick structure (100) as claimed in claim 1, wherein said wire rope (43) is connected to a load supporting mechanism (65) such as a hoist.
3. The derrick structure (100) as claimed in claim 1, wherein a rectangular block (68) having a lifting stud (69) to be held with a thread block (70) connected to one end of said I-beam lifting trolley (67A).
4. The derrick structure (100) as claimed in claim 1, wherein a bottom pulley (40) mounted on a tower bottom jig (45), said bottom pulley (40) coupled to said load supporting mechanism (65) via a wire rope (43).
5. The derrick structure (100) as claimed in claim 1, wherein said leg posts consists of a set of front leg posts (46), a front left side leg post (46A), a front right side leg post (46B), a rear post left hand side (47), and a rear post right hand side (47A).
6. The derrick structure (100) as claimed in claim 1, wherein said pulleys consists of a first pulley (41) connected to the front side of said monorail (55) and a second pulley (41A) connected to the rear side of said monorail (55) via studs (37) and nuts (37A).
7. The derrick structure (100) as claimed in claim 1, wherein said lifting jig (58) includes a plurality of beams, a lifting jig beam LH (59A) and a lifting jig beam RH (59B) horizontally disposed above said generator (32).
8. The derrick structure (100) as claimed in claim 7, wherein said lifting jig (58) includes a holder and a hook (33), said holder configured to hold said generator (32) thereof and said hook (33) configured to couple said holder with said third pulley (42).
9. The derrick structure (100) as claimed in claim 7, wherein said lifting jig (58) connected between a lifting jig side plate front (60A) and a lifting jig side plate back (60B), wherein said second pulley (41A) of said monorail (55) in vertical axis of said third pulley (42).
10. The derrick structure (100) as claimed in claim 1, wherein said structure (100) includes a steel rafters (74, 75) assembled in between the flanges of front right leg post (46B) and the flanges of rear right leg post (47A) such that the generator (32) can be moved laterally in a position suitable to facilitate lowering of said generator (32) on the ground.
11. The method for replacement of a generator of a wind turbine from said derrick structure (100), said method comprising:
• fixing a load supporting mechanism (65) on the ground in the vicinity of said wind turbine;
• fitting a plurality of leg posts on a nacelle chassis (24);
• fitting a front cross beams (53) and a rear cross beam(54) on the top of said leg posts (46, 47);
• fitting at least one monorails (55) longitudinally between a front cross beam (53) and a rear cross beam (54);
• mounting first pulley (41) on said monorail (55) near the operative front end and second pulley (41A) in the central portion of said monorail (55);
• fitting an I-beam lifting trolley (67A) to said monorail (55);
• mounting third pulley (42) at the central portion of a lifting jig (58);
• fixing the generator on said lifting jig (58); and
• actuating said load supporting mechanism (65) for drawing in said wire rope (43) and lifting said generator (32) from the ground level up to the nacelle chassis (24) and drawing out said wire rope (43) for lowering said generator (32) from said nacelle chassis (24) to the ground level.
12. The method as claimed in claim 11, wherein said generator (32) lifted from a nacelle cross frame (24A) and then moved towards the right hand side of said nacelle (21) up to a position suitable to facilitate lowering of said generator (32) on the ground.

Dated this 5th day of September, 2020

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI