DE202018102696U1 - Wind turbine and its leaf deicing device - Google Patents

Abstract

A sheet deicing apparatus comprising an electric heating element mounted on a blade, characterized in that said electrical heating element comprises a carbon fiber / glass fiber blended fabric (1) and an electrode assembly (2), said carbon fiber / glass blended fabric (1) comprising a longitudinal carbon fiber group (11 and a transverse carbon fiber group (12) intertwined with each other and glass fiber bundles (13) while the electrode assembly (2) is attached to both ends of each of the carbon fiber bundles of either the longitudinal carbon fiber group (11) or the transverse carbon fiber group (12).

Description

Field of the invention

The present invention relates to the field of power generation by means of wind power, in particular to a device for deicing a blade of a wind turbine.

Technical background

In some areas, the wind turbines erected there during the cold season are exposed to extreme weather conditions such as freezing, cold air intrusion, sleet, etc., so that the sheet is expected to be covered with iron, frost or snow. These phenomena can directly change the surface and cross-sectional shape of a blade, reduce the absorption of wind energy by a blade, cause operational mechanical damage to the equipment, increase the load on the equipment, and cause center of gravity displacement. At the same time, detachment of iron blocks poses a potential safety hazard for people and facilities in the field. In addition, overlapping the sheet with iron or snow can compromise the accuracy of the wind measurement, resulting in reduced energy yields and severe economic losses for the wind farm would.

From the prior art, as the defrosting method for the blade of a wind turbine, passive solution method, mechanical method, gas heating method, microwave method, passive method by endothermic coating, vibration method by electromagnetic shock, passive method by waterproof coating, shaking method, active electric heating method, etc. are known. This is where the active de-icing process of electrical heating is most commonly used today thanks to its high performance, low aerodynamic configuration and ease of maintenance.

For active deicing by means of electrical heating, it is mainly on a heat generation using a heat-generating layer of carbon fiber back to perform the actual deicing process can. To mount a carbon fiber fabric, it is first subjected to resin curing and then laid to the inside of the main body of a sheet. In addition, a bidirectional fiber arrangement is possible in each carbon fiber fabric layer. For example, the bidirectional carbon fiber cloths may be disposed at an angle of ± 15 ° to ± 75 °. Furthermore, each carbon fiber fabric layer must be continuous in the current flow direction, i. uninterrupted, run. However, in the bi-directionally braided carbon fabric according to the above-mentioned prior art, because of a certain braiding angle, a very complicated electrode or current source arrangement of the carbon fiber fabric occurs, which is not suitable for general practical use.

Another disadvantage is that, if no fixing operation is carried out for the braided carbon fiber bundles, hardening by resin injection easily causes arbitrary deformations, thereby making the positioning process difficult. The current carbon fiber bundles are mostly hollow, with the respective hollow area easily infiltrating after a vacuum-assisted resin infusion, which can make the surface of the sheet uneven and thereby affect the aerodynamic contour of the sheet. A re-leveling of the sunken area e.g. Filling or sanding would increase the workload considerably. Since the hollow carbon fiber bundles are insulated from each other only by air, i. no further insulating bodies are present between the hollow carbon fiber bundles, an integration of the carbon fiber bundles in the surrounding circuits and a short circuit caused thereby are to be expected. In addition, the carbon fiber bundles after curing by means of resin are hard, so now have a poor flexibility or flexibility and are not suitable for subsequent installation on the surface of a wing. The hitherto known production method for the galvanic electrodes of carbon fiber bundles should sufficiently ensure that each carbon fiber bundle is enveloped by the respective electroplating metal. However, a possible embrittlement of the thin galvanic layer during transport can lead to splitting of the electrode. If a break occurs in a certain carbon fiber thread, then the entire carbon fiber thread associated with this break point can no longer generate any heat, so that the corresponding surface area of the respective sheet could no longer be de-entailed.

Disclosure of the invention

The object of the invention is to provide a Blattenteisungsvorrichtung, with the preserving the aerodynamics of a sheet this effectively de-iced, the carbon fiber bundles protected against displacement and errors such as yarn displacements, short circuits, etc. can be avoided.

The invention is also based on the object to provide a wind turbine.

According to one aspect of the invention, the object is achieved by a sheet deicing apparatus comprising an electric heating element mounted on a sheet comprising a carbon fiber / glass fiber blended fabric and an electrode assembly, said carbon fiber / glass fiber blended fabric comprising a longitudinal carbon fiber group and a transverse carbon fiber group, which are intertwined with each other and glass fiber bundles while the electrode assembly is attached to both ends of each of the carbon fiber bundles of either the longitudinal carbon fiber group or the transverse carbon fiber group.

Optionally, it is contemplated that on both sides of the carbon fiber / fiberglass blended fabric, to which no electrode assembly is attached, a glass cloth of a certain width is interlaced to create a closure edge.

Optionally, it is contemplated that the electrode assembly includes a plurality of conductors each connected at both ends of each of the carbon fiber bundles of either the longitudinal carbon fiber group or the transverse carbon fiber group, two baffles disposed at both ends of the carbon fiber bundles and each with all conductors at the respective ends electrically connected, and a plurality of insulating sleeves, each of which cover the joint between each conductor and the associated carbon fiber bundle comprises.

Optionally, it is provided that the baffle is a flat silver-plated copper sheet.

Optionally, it is provided that in the normal heating operation of the electric heating element, the current flows only through the carbon fiber bundles connected to the electrode assembly, wherein at the occurrence of a break in a certain carbon fiber bundle connected to the electrode assembly, a portion of the current flowing in the breakage carbon fiber bundle stream over another Flechtmasche bypasses the breakage point and flows back into the carbon fiber bundle containing the breakage point.

Optionally, it is provided that the carbon fiber / fiberglass blended fabric has a density matched to the respective heating requirement of different locations of the sheet.

Optionally, it is provided that the electrode assembly is connected to the longitudinal carbon fiber group, wherein a closure edge is braided at both ends of the transverse carbon fiber group starting from the glass fiber bundles.

Optionally, it is contemplated that the carbon fiber / glass fiber blended fabric has a thickness of less than 1 mm, wherein the braided meshes of the carbon fiber / glass blended fabric comprise rectangular or square meshes of 7-23 mm in length.

Optionally, it is provided that the glass fiber bundles fill the spaces between the longitudinal carbon fiber group and the transverse carbon fiber group.

According to another aspect of the invention, the object is achieved by a wind turbine comprising a blade to which the above-described sheet deicing device is attached.

1. 1) Die längsgerichtete Kohlenstofffasergruppe und die quergerichtete Kohlenstofffasergruppe sind in senkrecht zueinander verlaufenden Richtungen miteinander verflochten, wobei Glasfaserbündel als Isolierstoff zum Einsatz kommen, um Fehler wie Fadenverschiebungen zwischen benachbarten Kohlenstofffaserbündeln und dadurch herbeigführte Kurzschlüsse zu vermeiden;
2. 2) Durch das Ausfüllen der Freiräume zwischen den Kohlenstofffaserbündeln mit Glasfaserbündeln wird einerseits ein elektrisches Heizelement ohne Leerstellen erzeugt und andererseits eine Positionierung der Kohlenstofffaserbündel erreicht, wodurch die Kohlenstofffaserbündel während einer vakuumunterstützten Harzinfusion gegen Verlagerung geschützt werden und zugleich eine Ebenheit der Oberfläche des Blatts sichergestellt wird;
3. 3) Die längsverlaufenden Kohlenstofffaserbündel und die querverlaufenden Kohlenstofffaserbündel sind miteinander zu Maschen verflochten, so dass auch beim Vorhandensein einer Bruchstelle in einem der Kohlenstofffaserbündel die Heizwirkung aufrechterhalten wird;
4. 4) Das Blatt lässt sich in Abhängigkeit von seiner Vereisung von Stelle zu Stelle unterschiedlich erwärmen, um eine ausreichende Enteisung zu erreichen und eine elektrische Energieverschwendung zu vermeiden;
5. 5) Die Elektrodenbaugruppe ist einfach und schnell montierbar, was die Montage der Blattenteisungsvorrichtung erleichtert;
6. 6) Das elektrische Heizelement kann nach dem Leistungsbedarf des jeweiligen Schleifrings verschiedener Windkraftanlagenmodelle jeweils in entsprechender Größe oder Flechtdichte hergestellt werden.

The invention offers the following advantageous effects:

1. 1) The longitudinal carbon fiber group and the transverse carbon fiber group are intertwined with each other in mutually perpendicular directions using glass fiber bundles as insulating material to avoid defects such as yarn displacements between adjacent carbon fiber bundles and short circuits caused thereby;
2. 2) By filling the spaces between the carbon fiber bundles with glass fiber bundles, on the one hand an electric heating element without voids is created and on the other hand positioning of the carbon fiber bundles is achieved, thereby protecting the carbon fiber bundles against displacement during vacuum assisted resin infusion while ensuring flatness of the surface of the sheet;
3. 3) The longitudinal carbon fiber bundles and the transverse carbon fiber bundles are intertwined into meshes so that even if there is a break in one of the carbon fiber bundles, the heating effect is maintained;
4. 4) The sheet may be heated differently from location to location depending on its icing to achieve adequate deicing and to avoid electrical waste of energy;
5. 5) The electrode assembly is simple and quick to install, which facilitates assembly of the sheet deicing device;
6. 6) The electrical heating element can be made according to the power requirements of the respective slip ring of various wind turbine models each in the appropriate size or braiding.

list of figures

• 1 in schematischer Darstellung ein elektrisches Heizelement einer Blattenteisungsvorrichtung gemäß einem Ausführungsbeispiel der Erfindung,
• 2 bis 7 einen Herstellungsablauf der Blattenteisungsvorrichtung gemäß dem Ausführungsbeispiel der Erfindung.

Show it

• 1 a schematic representation of an electrical heating element of a Blattenteisungsvorrichtung according to an embodiment of the invention,
• 2 to 7 a manufacturing process of the Blattenteisungsvorrichtung according to the embodiment of the invention.

LIST OF REFERENCE NUMBERS

1

Carbon fiber / glass fiber blended fabric

2

electrode assembly

11

Longitudinal carbon fiber group

12

Transverse carbon fiber group

13

glass fiber bundle

21

metal sleeve

22

ladder

23

insulating sleeve

24

baffle

Concrete embodiments

For a better understanding of the invention will be discussed in more detail below with reference to the accompanying drawings to the specific embodiments of the invention.

Out 1 shows an electrical heating element of a Blattenteisungsvorrichtung according to an embodiment of the invention. In terms of in 1 The mounting position of the electric heating element on a blade is defined as the length direction of the blade as the longitudinal direction and the chordwise direction of the blade as the transverse direction. Despite this definition, the electric heating element in practice can also be mounted rotated by 90 °, so that the horizontal direction and the vertical direction are interchangeable with each other, ie the fastening position provided here is not to be understood as limiting.

According to the embodiment of the invention, a sheet deicing device is proposed, which is generally attachable to the location of a sheet at which ice formation or snow accumulation is to be expected. For example, the sheet deicing device may be pre-embedded within a sheet or externally attached to the surface of a sheet to remove ice or snow and thus recover the normal generator power of the wind turbine.

The sheet deicing apparatus comprises an electric heating element disposed on a sheet and two groups of carbon fiber bundles, namely, a longitudinal carbon fiber group 11 and a transverse carbon fiber group 12 , includes. Each of the carbon fiber groups includes a plurality of carbon fiber bundles such that longitudinal carbon fiber bundles, transverse carbon fiber bundles, and glass fiber bundles 13 are intertwined (ie the two groups of carbon fiber bundles are braided perpendicular to each other). With the glass fiber bundles 13 For example, the clearances between the longitudinal carbon fiber bundles and the transverse carbon fiber bundles can be filled in or completely filled to form a dense carbon fiber / fiberglass blended fabric 1 without creating voids, which ensures flatness of the surface of the sheet. The longitudinal carbon fiber group 11 and the transverse carbon fiber group 12 are electrically connected to each other at the nodes of the individual braiding meshes. With the glass fiber bundles, the carbon fiber bundles can not only be positioned and insulated from each other to avoid thread shifting between adjacent carbon fiber bundles and short circuit caused thereby, but also reliably protected against displacement during vacuum assisted resin infusion and attachment to achieve good dimensional stability.

Additionally, the sheet deicing apparatus includes an electrode assembly 2 at both ends of the longitudinal carbon fiber group 11 or the transverse carbon fiber group 12 is attached and connected to all the carbon fiber bundles in the respective carbon fiber group to supply each of the carbon fiber bundles with an electric power of the same height.

As it turned out 1 is at both ends of the longitudinal carbon fiber group 11 one electrode assembly each 2 each connected as a positive and negative electrode, respectively, to provide each longitudinal carbon fiber bundle with electrical energy. At both ends of the transverse carbon fiber group 12 where there is no electrode assembly 2 is mounted, a glass fiber fabric is additionally braided (not shown) to produce a closure edge. This fiberglass fabric can transversely a have adequate width of, for example, about 20 mm to function as an insulating layer.

Instead, it is also conceivable that at both ends of the transverse carbon fiber group 12 one electrode assembly each 2 is connected while at both ends of the longitudinal carbon fiber group 11 a glass fiber fabric is interlaced to produce a closure edge. Alternatively, it may also be at both ends of the longitudinal carbon fiber group 11 starting from the glass fiber bundles 13 a closure edge can be braided, which may consist of other suitable insulating materials.

In the normal heating operation of the sheet deicing apparatus, each carbon fiber bundle becomes in the longitudinal carbon fiber group 11 applied with an equal high voltage, so that the longitudinal carbon fiber bundles is equivalent to a parallel circuit, wherein the current flows only through the longitudinal carbon fiber bundles to perform a heating operation. When a break occurs in a certain longitudinal carbon fiber bundle, a portion of the current flowing in this carbon fiber bundle bypasses the braiding mesh in which the fracture site is located and flows back into this carbon fiber bundle via an adjacent loop (ie, that in the carbon fiber bundle portion on the carbon fiber bundle) Side of the break point Current flowing, bypassing the break point, flows over an adjacent braiding mesh into the section of the carbon fiber bundle opposite the breakage point). Specifically, a current component flows upwardly or downwardly through the transverse carbon fiber bundle located in front of the fracture site to enter an adjacent longitudinal carbon fiber bundle, then into the transverse carbon fiber bundle located behind the fracture site, and finally back into the fractured site portion of the carbon fiber bundle containing the fracture site , Other current components may flow into other carbon fiber bundles, changing the current field in the vicinity of the breakpoint, so that the currents in some longitudinal carbon fiber bundles increase, and in some transverse carbon fiber bundles also current flow occurs, causing some heating and thus deicing of the sheet surface favored.

In this sense, even in the event of a fault, such as in the presence of a break, the electric heating unit can ensure continuous defrosting and even assist in heating the environment of the breakage point.

In general, the carbon fiber / glass fiber blended fabric 1 have a thickness of less than 1 mm. The longitudinal carbon fiber bundles and the transverse carbon fiber bundles may be intertwined into square or rectangular meshes having an edge length in the range of 7-23 mm. Of course, depending on the heating requirement, an edge length of less than 7 mm or greater than 23 mm is conceivable.

Since a sheet is usually iced differently or covered with snow from place to place, it may be necessary to heat different locations of a sheet differently. In the embodiment of the invention, the carbon fiber / glass fiber blended fabric 1 in different sizes, ie in different web widths and lengths, cut and laid at different locations on a sheet. For a desired heating of the areas of the sheet to be deiced, a corresponding adjustment of the size of the braiding stitches, ie a change in the braided density or density, can furthermore be provided in order to be able to set the heating power. To set different heating powers can also be the model of carbon fiber bundles used or the rated power of the power source to which the electric heating element is connected, change. In this way, the heating power of the electric heating element can be adapted to the respective deicing need of different locations of the blade to preclude insufficient or excessive heating of the blade.

In addition, the heating power of the electric heating element can be adjusted according to the power requirement of the respective slip ring of various wind turbine models.

The following will be on 2 to 7 Referenced to the assembly process of the electrode assembly 2 the Blattenteisungsvorrichtung represent.

First, carbon fiber bundles and glass fiber bundles are intertwined with each other according to design specifications and sizes to form a seal edge and then cut into a semi-finished product. Thereafter, a respective metal ferrule 21 is placed on both ends of each of the longitudinal carbon fiber bundles in the longitudinal carbon fiber group, respectively, and a conductor is formed on both ends of each of the longitudinally extending carbon fiber bundles 22 connected. Finally, the metal sleeves 21 flattened (see 5 ) to the junction between the carbon fiber bundle and the conductor 22 to solidify.

Thereafter, the joint between the carbon fiber bundle and the conductor 22 with an insulating sleeve 23 equipped or wrapped with a Isolierstofflage. Subsequently, each at the two longitudinal ends of a one-piece baffle 24 arranged from below against the ladder 22 so presses that ladder 22 in electrical connection with the baffle 24 kick and from the baffle 24 can receive the same voltage.

Finally, the baffle can be 24 connect to a power source so that the baffle 24 Each of the longitudinal carbon fiber bundles can act with an equally high voltage.

In the embodiment of the invention, it may be at the baffle 24 to trade a flat silver plated copper sheet. By using a flat silver-plated copper sheet as baffle 24 On the one hand, it is possible to achieve a balance between the optimum conductivity and the economy and, on the other hand, the electrical conductivity of the guide plate 24 be improved.

In the proposed sheet deicing apparatus, the longitudinal carbon fiber group and the transverse carbon fiber group are longitudinally and transversely interlaced using glass fiber bundles as insulating material to avoid defects such as yarn displacements between adjacent carbon fiber bundles and short circuits caused thereby. By filling the spaces between the carbon fiber bundles with glass fiber bundles, on the one hand an electrical heating element without voids is generated and on the other hand positioning of the carbon fiber bundles is achieved, thereby protecting the carbon fiber bundles from displacement during vacuum-assisted resin infusion while ensuring flatness of the surface of the sheet. The longitudinal carbon fiber bundles and the transverse carbon fiber bundles each extend in the longitudinal or transverse direction and shriek thereby, so that even in the presence of a break in one of the carbon fiber bundles, the heating effect is maintained. In this case, the sheet can be heated differently depending on the icing from place to place in order to achieve adequate deicing and avoid electrical energy waste.

According to a further exemplary embodiment of the invention, a wind power plant is provided on whose blade the above-described leaf defroster device can be attached.

Attempts have been made on a de-icer prototype for a 2.0MW wind turbine with the electrical heating element of the leaf deicing apparatus having a power density of 386 W / m ² . At an ambient temperature of less than 0 ° C, icing of the blade of the wind turbine prototype was observed. After switching on the Blattenteisungsvorrichtung the wind turbine could be operated substantially normal, ie the icing did not stop the wind turbine. On the other hand, icing in a non-de-icing facility resulted in large power losses, causing the plant to come to a standstill. From a comparison of the power and the energy yield between the de-icing by means of the sheet deicing apparatus according to the invention and a standard iced system shows that in this icing period the de-entailment system generated by approximately 40,000 kWh more electrical energy than the non-deiced system.

So far, specific embodiments of the invention have been described in detail. It will be apparent to those skilled in the art that, within the scope of the principles and principles of the invention as defined by the claims and equivalents, variations and improvements of the embodiments illustrated herein may be made which are also within the scope of the invention.

Claims (10)

A sheet deicing apparatus comprising an electric heating element mounted on a blade, characterized in that said electrical heating element comprises a carbon fiber / glass fiber blended fabric (1) and an electrode assembly (2), said carbon fiber / glass blended fabric (1) comprising a longitudinal carbon fiber group (11 and a transverse carbon fiber group (12) intertwined with each other and glass fiber bundles (13) while the electrode assembly (2) is attached to both ends of each of the carbon fiber bundles of either the longitudinal carbon fiber group (11) or the transverse carbon fiber group (12). Leaf deicing device according to Claim 1 , characterized in that on both sides of the carbon fiber / glass fiber blended fabric (1), to which no electrode assembly (2) is attached, a glass fiber fabric having a certain width is interlaced to produce a sealing edge. Leaf deicing device according to Claim 1 characterized in that the electrode assembly (2) has a plurality of conductors (22) respectively connected thereto at both ends of each of the carbon fiber bundles of one of the longitudinal carbon fiber group (11) and the transverse carbon fiber group (12), two baffles (24) arranged at both ends of the carbon fiber bundles and in each case with all conductors (22) electrically connected to the respective end, and a plurality of insulating sleeves (23), which respectively cover the joint between each conductor (22) and the associated carbon fiber bundle comprises. Leaf deicing device according to Claim 3 , characterized in that it is the guide plate (24) is a flat silver plated copper sheet. Leaf deicing device according to Claim 1 characterized in that, in the normal heating operation of the electric heating element, the current flows only through the carbon fiber bundles connected to the electrode assembly (2), wherein upon occurrence of a break in a certain carbon fiber bundle connected to the electrode assembly (2), a portion of the carbon fiber bundle contained in the fracture site flowing stream over another braiding mesh bypasses the breakage point and flows back into the carbon fiber bundle containing the breakage point. Leaf deicing device according to Claim 1 , characterized in that the carbon fiber / glass fiber blended fabric (1) has a matched to the respective heating requirements of different locations of the sheet braided density. Leaf deicing device according to Claim 1 characterized in that the electrode assembly (2) is connected to the longitudinal carbon fiber group (11), wherein at both ends of the transverse carbon fiber group (12) from the glass fiber bundles (13) a closure edge is braided. Leaf deicing device according to Claim 2 characterized in that the carbon fiber / glass fiber blended fabric (1) has a thickness of less than 1 mm, the braided meshes of the carbon fiber / glass blended fabric (1) comprising rectangular or square meshes of 7-23 mm edge length. Leaf deicing device according to Claim 1 characterized in that the glass fiber bundles (13) fill the spaces between the longitudinal carbon fiber group (11) and the transverse carbon fiber group (12). Wind turbine, comprising a sheet, characterized in that on the sheet a Blattenteisungsvorrichtung according to one of Claims 1 to 9 is appropriate.

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