Title of Invention

A WIND POWER INSTALLATION ROTOR BLADE

Abstract Described is a rotor blade for a wind power installation having a rotor blade nose. A deposit sensor device is arranged in the region of the rotor blade nose. That deposit sensor device has a transmitter for the wireless transmission of signals by way of a transmission link and a receiver for receiving the signals wirelessly transmitted by way of the transmission link. Deposits on the surface can be detected in the region of the transmission link on the basis of the signals transmitted by way of the transmission link.
Full Text Aloys Wobben
Argestrasse 19, 26607 Aurich
Rotor blade for a wind power station
The present invention concerns a rotor blade for a wind power
installation as well as a wind power installation having a corresponding
rotor blade.
In relation to wind power installations it is desirable in particular in
the cold time of the year to detect icing on the rotor blades in order to
implement suitable de-icing measures. Icing of the rotor blades is not
wanted as the icing causes an increase in the weight of the rotor blades. In
addition lumps of ice which come away from the rotor blade during
operation of a wind power installation can become dangerous projectiles
and can cause injury to persons or damage to property. Furthermore
lumps of ice which come away from the rotor blade can result in unbalance
of the rotor. blades, which ultimately can have the result that the
installation has to be shut down. However it is undesirable for economic
reasons to shut down the installation.
In order to prevent that many wind power installations have a
heating arrangement for the rotor blades in order to prevent the first
beginnings of icing. Furthermore the wind power installations can also be
shut down in the event of incipient ice formation. In that case however it is
necessary to reliably detect incipient ice formation.
With known sensor systems for detecting the first beginnings of icing
on a rotor blade of a wind power installation the corresponding sensors are
installed on the pod of the installation. That means however that it is not
possible to achieve direct comparability of the flow and icing conditions as
different flow conditions prevail at the rotor blade.
DE 202 06 704 discloses an ice sensor for a wind power installation.
The ice sensor is disposed in the proximity of the rotor blade tips. The data
ascertained are processed having regard to the basic meteorological
conditions in order to be able to undertake suitable measures.
1

As state of the art attention is also directed generally at this juncture
to the following publications: DE 199 27 015 Al, DE 103 15 676 Al, DE
101 60 522 Al and DE 200 21 970 Ul.
Therefore the object of the present invention is to provide a rotor
blade for a wind power installation, which can distinguish between deposits
such as dirt and incipient ice formation.
That object is attained by a rotor blade as set forth in claim 1 and by
a wind power installation as set forth in claim 11.
Thus there is provided a rotor blade for a wind power installation
having a rotor blade nose. A deposit sensor device is disposed in the
region of the rotor blade nose. That deposit sensor device has a
transmitter for the wireless transmission of signals by way of a
transmission link and a receiver for receiving the signals wirelessly
transmitted by way of the transmission link. On the basis of the signals
communicated by way of the transmission link it is possible to detect
deposits on the surface in the region of the transmission link.
Accordingly there is provided a rotor blade having a deposit sensor
device which is capable of quickly and reliably detecting deposits on the
surface of the rotor blade.
In accordance with an aspect of the present invention the rotor blade
or the wind power installation has a comparison device which serves to
compare the signals transmitted by the transmitter and received by the
receiver in order to establish changes. By virtue of establishing the
changes in the transmitted signals it is possible to directly establish the
extent to which the transmission behavior of the transmission link changes
so that deposits can be detected directly.
In accordance with a further aspect of the present invention the
comparison device has a storage device for storing the detected changes in
respect of the received signals so that a data bank is set up. Conclusions
regarding the frequency and the conditions when deposits occur can be
ascertained on the basis of the data bank.
In accordance with a preferred aspect of the present invention the
deposit sensor device represents an optical sensor device. Detection of
2

deposits is thus effected based on optical signals so that there is no
interaction with the electronic and electrical components of the wind power
installation.
In accordance with a further aspect of the present invention the
transmitter has a coupling-out lens and the receiver has a coupling-in lens.
The effectiveness in terms of the transmission of the optical signals can be
improved in that way.
In accordance with a further preferred aspect of the present
invention both the transmitter and also the receiver are respectively
connected to the comparison device by way of optical waveguides. In that
fashion it is possible to avoid electric lines in the rotor blade in order further
to improve protection from lightning.
Further aspects of the present invention are the subject-matter of
the appendant claims.
The invention and embodiments by way of example thereof are
described in greater detail hereinafter with reference to the drawings in
which:
Figure 1 shows a front view of a wind power installation in
accordance with the first embodiment,
Figure 2 shows a sectional view of a portion of a rotor blade of the
wind power installation of Figure 1,
Figure 3 shows a plan view of a portion of a rotor blade of the wind
power installation of Figure 1, and
Figure 4 shows a plan view of a portion of a rotor blade of a wind
power installation in accordance with a second embodiment.
Figure 1 shows a front view of a wind power installation in
accordance with a first embodiment. In this arrangement the wind power
installation has a pylon 10, a pod 20 and three rotor blades 30. A deposit
sensor 1 is arranged at each of the rotor blades. Preferably the deposit
sensor 1 is arranged at the rotor blade nose. The deposit sensors 1 are
each connected to a comparison device 3 by way of optical waveguides 2.
Figure 2 shows a sectional view of a portion of a rotor blade 30 of
the wind power installation of Figure 1. In particular the portion of the
3

rotor blade in the region of the deposit sensor 1 is illustrated here. The
deposit sensor is mounted in the region of the rotor blade nose 31 of the
rotor blade 30. The deposit sensor 1 substantially comprises an optical
transmitter 11 and an optical receiver 12. The optical transmitter 11 is
provided with a coupling-out lens 11a and the optical receiver 12 is
provided with a coupling-in lens 12a. The optical transmitter 11 and the
optical receiver 12 are each connected to the comparison device 3 by way
of optical waveguides 11b, 12b, 2. An optical transmission link 13 is
provided between the coupling-out lens lla and the coupling-in lens 12a.
That optical transmission link extends substantially parallel to the surface of
the rotor blade nose 31.
Thus the deposit sensor 1 is mounted directly to the rotor blade of
the wind power installation so that the corresponding deposits such as for
example soiling with dirt and icing can be ascertained directly on the rotor
blade. Preferably the deposit sensors are arranged in the outer third of the
rotor blade (see Figure 1) as here there is a higher level of certainty in
terms of recognizing deposits such as for example dirt soiling and icing. In
addition thereto it is possible to arrange further deposit sensors 1 at other
locations on the rotor blade so that it is possible to obtain a system with
multiple redundancy.
As electric lines in a rotor blade of a wind power installation are not
desirable in terms of protection from lightning, the sensor system according
to the invention is divided substantially into two parts, namely the actual
sensor and the evaluation unit. Preferably in that case the comparison unit
is arranged in the blade root of the rotor blade or at a rotating part of the
machine housing. The optical sensor and receiver in contrast are arranged
on the rotor blade itself. Transmission of the light signal from the
comparison device to the optical receiver is preferably effected by way of
optical waveguides so that it is possible to avoid further electric lines in the
rotor blade. As an alternative thereto the comparison device can also be
arranged directly in or at the deposit sensor 1 if suitable protection from
lightning is provided.
4

Preferably the connections between the optical transmitter 11 and
the optical receiver 12 and the respective optical waveguides 11b, 12b, 2
are ensured by means of plug contacts or by means of a screw
arrangement. Accordingly the deposit sensor 1 can be replaced in a simple
fashion without the entire rotor blade having to be replaced in that case.
As shown in Figure 2 the deposit sensor 1 preferably has a coupling-
out lens 11a and a coupling-in lens 12a in order to permit a low level of
attenuation of the light beam between the optical transmitter 11 and the
optical receiver 12. As soon as deposits occur in the optical transmission
link 13, the transmission characteristics of that transmission link 13 are
altered, and that can be detected by the comparison device 3.
Figure 3 shows a plan view of a portion of the rotor blade of Figure 1
in the region of the deposit sensor 1. In this case the deposit sensor 1 is
fixedly connected to the rotor blade nose 31 of the rotor blade 30. That
can be effected by screw means or adhesive. In this case the optical
transmission link 13 is oriented substantially parallel to the rotor blade nose
in the longitudinal direction of the rotor blade. Preferably the position of
the optical sensor 11 and of the optical receiver 12 should be arranged in
the region of the profile stagnation point as that represents the most
probable location for the beginnings of a deposit. The external
configuration of the deposit sensor 1, which is shown in Figure 3, ensures a
low-loss flow around the deposit sensor 1. In addition, in the region of the
air gap, that is to say the optical transmission link 13, by virtue of the
channeling effect on the flow around the rotor blade nose, the illustrated
configuration of the deposit sensor 1 serves to prevent dirt soiling at the
optical transmitter and receiver. By virtue of the particular configuration of
the deposit sensor the directional vectors of the flow are never directed
directly in the direction of the optical transmitter 11 and the optical receiver
12 or the entry or exit locations thereof.
Rather, the directional vectors of the flow are arranged substantially
perpendicularly thereto. The recessing of the deposit sensor 1 in the nose
contour, which occurs due to the optical transmission link 13, should
preferably be sufficiently wide to not noticeably alter the formation
5

mechanisms involved in the formation for example of ice and sufficiently
narrow to ensure minimum attenuation or influencing of the light beam in
the optical transmission link 13 due to dirt soiling or deformation of the
blade.
In order to reduce the influence of the incident sunlight on the
optical receiver 12 the light beam transmitted by way of the transmission
link 13 is preferably pulsed. With a suitable arrangement, it is possible to
implement raster-controlled ice thickness measurement by means of
further miniaturization of the deposit sensor 1.
Figure 3 shows a plan view of a portion of a rotor blade nose of a
rotor blade for a wind power installation in accordance with a second
embodiment. In this case the deposit sensor 1 in accordance with the
second embodiment is based on the same operating principle as the deposit
sensor 1 in accordance with the first embodiment, that is to say there are
provided an optical transmitter 16, an optical receiver 17 as well as an
optical transmission link 18 between the transmitter 16 and the receiver
17. While in the first embodiment the deposit sensor is substantially
matched to the contour of the rotor blade nose, the deposit sensor in the
second embodiment is implemented by needle-form or pin-form optical
waveguides which issue from the profile nose or the rotor blade nose.
In the second embodiment the deposit sensor 1 is embodied by two
pin-form optical waveguides 14, 15 which protrude out of the surface of the
rotor blade and which have a lateral beam exit. Deflection of the light
beam through 90° by means of suitable lenses or prisms means that optical
waveguides can be passed in the interior of the rotor blade to the underside
of the lenses 14, 15. The light beam is then coupled to the lens and
deflected through 90° by the lens or the prism respectively so that the light
beam can extend substantially parallel to the surface of the rotor blade
over the optical transmission link 18 from the optical transmitter 16 to the
optical receiver 17. The optical receiver 17 also has a lens or a prism in
order to deflect the light beam through 90° and to couple it into the
returning optical waveguide.
6

In substance the structure in principle of the deposit sensor 1 of the
second embodiment corresponds to that of the first embodiment. In the
second embodiment however the structure is of a substantially simpler
configuration. Furthermore, a modification to the rotor blade at its nose
contour is only necessary to a very slight extent. Preferably the optical
transmitter 16 and the optical receiver 17 are designed so that they can be
screwed to or plugged into the corresponding lenses for 90° deflection so
that they can be readily replaced if required.
Preferably the optical transmitter 16 and the optical receiver 17 are
not arranged precisely at the foremost point of the rotor blade nose but in
slightly displaced relationship therewith. In other words: the deposit
sensor 1 is not arranged in the foremost region of the blade nose, that is to
say the nose line. The deposit sensor 1 can thus be arranged in the region
of the blade nose.
Preferably the deposit sensor in accordance with the first or the
second embodiment should be arranged in the region of the rotor blade
nose, in the region of the stagnation point. In that respect the stagnation
point represents the point at which the airflow impinges on the blade and is
then divided into a first flow along the suction side and a second flow along
the pressure side. In the region of that stagnation point incipient ice
formation will begin and will then build up further in accordance with a
random pattern. It is not possible to make a precise prediction about the
position of the stagnation point as that is also dependent on the angle of
incidence of the rotor blade.
The height of the optical transmitter 16 and the optical receiver 17 or
the lenses thereof can be adapted to be adjustable over the surface of the
rotor blade. That can be achieved by the optical transmitter 16 and the
optical receiver 17 protruding to a greater or lesser distance out of the
rotor blade surface. The spacing between the optical transmitter 16 and
the optical receiver 17 can be between 10 and 100 mm, preferably 20 and
50 mm. The spacing between the light beam between the optical
transmitter 16 and the optical receiver 17 and the rotor blade surface (that
is to say the spacing of the light beam from the rotor blade surface) is
7

between 2 and 10 mm and preferably between 5 and 6 mm. The spacing
between the surface of the rotor blade and the light beam between the
optical transmitter and the optical receiver determines the thickness of ice
which can be detected. In that respect an ice thickness below 2 mm can
remain disregarded while a thicker layer of ice than preferably 5-6 mm
can lead to considerable problems.
In order to permit simplified replacement of the lens, it is possible to
provide in the rotor blade socket sleeves into which a lens, that is to say an
optical transmitter or an optical receiver, can be fitted. Preferably a
positively locking connection such as for example a bayonet connection is
provided between the sleeve and the optical transmitters and optical
receivers. Alternatively or in addition thereto the sleeves and the optical
transmitter and the optical receiver can be screwed together. That is
advantageous in particular to the effect that the optical receivers and
optical transmitters are more stably protected against incipient icing and
are not torn out of the blade during an ice removal operation and fall down
with the ice.
In accordance with a further embodiment based on the first or the
second embodiment the comparison device 3 can have a storage device in
which characteristic deposits are stored so that in operation they can be
compared to the values which are actually detected. Accordingly it is
possible for example to distinguish whether the deposits only involve soiling
due to bird droppings or dust or whether the situation involves incipient ice
formation. In addition thereto the comparison device 3 can process further
data from the environment of the wind power installation. Those data can
represent for example temperature data so that for example the deposit
sensor 1 can be switched off as from a temperature of 3°C as ice formation
is not to be expected as from such temperatures.
In addition the comparison device can have a data bank storage
device in which the detected changes can be stored and possibly evaluated
in order for example to be able to establish an icing pattern in order
. possibly to permit suitable early recognition.
8

The comparison device can also be arranged outside the rotor blade,
for example in the region of the hub, which has the advantage that electric
lines do not have to be laid in the rotor blade. In such a case the rotor
blade, in the transitional region to the hub, has one or more suitable
connections or couplings in order to couple the deposit sensor to the
comparison device. In that way it can be provided that only optical
waveguides have to be laid in the rotor blade, which is found to be
advantageous in particular in regard to protection from lightning.
9

1. A rotor blade (30) for a wind power installation comprising
a rotor blade nose (31),
a deposit sensor device (1, 11, 12, 13) arranged in the region of the
rotor blade nose (31) and having a transmitter (11) for wirelessly
transmitting signals by way of a transmission link (13) and a receiver (12)
for receiving the signals wirelessly transmitted by way of the transmission
link (13),
wherein those deposits on the surface of the rotor blade (30) which
are in the direct region of the transmission link (13) of the wirelessly
transmitted signal are detected on the basis of the signals transmitted by
way of the transmission link (13),
wherein the transmission link (13) between the transmitter (11) and j
the receiver (12) extends substantially parallel to the rotor blade nose (31).
10

2 A rotor blade (30) as set forth in claim 1 comprising
aicomparison device (3) for comparing the.signals transmitted by the
transmitter (11) and received by the receiver (12) in order to detect
changes; in the received signals.
3.; A rotor blade (30) as set forth in claim 1 comprising
a i connection for coupling an external comparison device to the
deposit sensor device (1, 11, 12, 13), wherein the signals transmitted, by
the transmitter (11) and received by the receiver (12) are compared in the
comparison device in order to detect changes in the received signals.
4. A rotor blade (30) as set forth in claim 1, claim 2 or claim 3
wherein the deposit sensor deviqe is adapted for continuously detecting
deposits or for detecting deposits at predetermined time intervals.
5. A rotor blade (30) as set forth in claim 2, claim 3 or claim 4;
wherein
the comparison device (3) has a storage device for storing the;
detected changes in order to produce a data bank.
6. A rotor blade (30) as set forth in one of the preceding claims
wherein
10a

the deposit sensor device (1, 11, 12, 13) represents an optical
sensor device.
7. A rotor blade (30) as set forth in claim 6 wherein
the transmitter (11) has a coupling-out lens (lla) and the receiver
(12) has a coupling-in lens (12a).
8. A rotor blade (30) as set forth in one of the preceding claims
wherein
the transmitter (11) and the receiver (12) are each connected to the
comparison device (3) by way of optical waveguides (lib, 12b).
9. A rotor blade (30) as set forth in one of the preceding claims
wherein
a transition in each case between the transmitter (11) and the
surface of the rotor blade (30) and between the receiver (12) and the
surface of the rotor blade (30) is of a sharp-edged configuration.
10. A rotor blade (30) as set forth in one of the preceding claims
wherein
the transmitter (11) and the receiver (12) protrude in pin form out of
the surface of the rotor blade.
11. A rotor blade as set forth in one of the preceding claims wherein
the transmission link (13) between the transmitter (11) and the
receiver (12) extends substantially parallel to the rotor blade nose (31)
12. A wind power installation comprising at least one rotor blade as
set forth in one of claims 1 to 11.

Described is a rotor blade for a wind power installation having a rotor
blade nose. A deposit sensor device is arranged in the region of the rotor
blade nose. That deposit sensor device has a transmitter for the wireless
transmission of signals by way of a transmission link and a receiver for
receiving the signals wirelessly transmitted by way of the transmission link.
Deposits on the surface can be detected in the region of the transmission
link on the basis of the signals transmitted by way of the transmission link.

Documents:

02164-kolnp-2007-abstract.pdf

02164-kolnp-2007-claims 1.0.pdf

02164-kolnp-2007-claims 1.1.pdf

02164-kolnp-2007-correspondence others 1.1.pdf

02164-kolnp-2007-correspondence others-1.2.pdf

02164-kolnp-2007-correspondence others.pdf

02164-kolnp-2007-description complete.pdf

02164-kolnp-2007-drawings.pdf

02164-kolnp-2007-form 1.pdf

02164-kolnp-2007-form 18.pdf

02164-kolnp-2007-form 3-1.1.pdf

02164-kolnp-2007-form 3.pdf

02164-kolnp-2007-form 5.pdf

02164-kolnp-2007-gpa.pdf

02164-kolnp-2007-international publication.pdf

02164-kolnp-2007-international search report.pdf

02164-kolnp-2007-other pct form.pdf

02164-kolnp-2007-pct request form.pdf

02164-kolnp-2007-priority document.pdf

2164-KOLNP-2007-ABSTRACT.pdf

2164-KOLNP-2007-AMANDED CLAIMS.pdf

2164-kolnp-2007-claims 1.2.pdf

2164-KOLNP-2007-CORRESPONDENCE 1.3.pdf

2164-KOLNP-2007-CORRESPONDENCE-1.2.pdf

2164-KOLNP-2007-CORRESPONDENCE-1.4.pdf

2164-KOLNP-2007-DESCRIPTION (COMPLETE).pdf

2164-KOLNP-2007-DRAWINGS.pdf

2164-KOLNP-2007-EXAMINATION REPORT REPLY RECIEVED.pdf

2164-KOLNP-2007-EXAMINATION REPORT.pdf

2164-KOLNP-2007-FORM 1.pdf

2164-KOLNP-2007-FORM 18.pdf

2164-KOLNP-2007-FORM 2.pdf

2164-KOLNP-2007-FORM 3-1.1.pdf

2164-KOLNP-2007-FORM 3.pdf

2164-KOLNP-2007-FORM 5.pdf

2164-KOLNP-2007-FORM-27.pdf

2164-KOLNP-2007-GPA.pdf

2164-KOLNP-2007-GRANTED-ABSTRACT.pdf

2164-KOLNP-2007-GRANTED-CLAIMS.pdf

2164-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

2164-KOLNP-2007-GRANTED-DRAWINGS.pdf

2164-KOLNP-2007-GRANTED-FORM 1.pdf

2164-KOLNP-2007-GRANTED-FORM 2.pdf

2164-KOLNP-2007-GRANTED-LETTER PATENT.pdf

2164-KOLNP-2007-GRANTED-SPECIFICATION.pdf

2164-KOLNP-2007-OTHERS 1.1.pdf

2164-kolnp-2007-others 1.2.pdf

2164-KOLNP-2007-OTHERS.pdf

2164-KOLNP-2007-PA.pdf

2164-KOLNP-2007-PETITION UNDER RULE 137.pdf

2164-KOLNP-2007-REPLY TO EXAMINATION REPORT-1.1.pdf

abstract-02164-kolnp-2007.jpg


Patent Number 248679
Indian Patent Application Number 2164/KOLNP/2007
PG Journal Number 31/2011
Publication Date 05-Aug-2011
Grant Date 03-Aug-2011
Date of Filing 13-Jun-2007
Name of Patentee WOBBEN ALOYS
Applicant Address ARGESTRASSE 19, 26607 AURICH
Inventors:
# Inventor's Name Inventor's Address
1 WOBBEN ALOYS ARGESTRASSE 19, 26607 AURICH
PCT International Classification Number F03D11/00,G01W1/00
PCT International Application Number PCT/EP2005/056726
PCT International Filing date 2005-12-13
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102004 060449.5 2004-12-14 Germany
2 102005 017716.6 2005-04-15 Germany