Title of Invention	METHOD FOR MOINTORING A SENSOR
Abstract	The present invention concerns a method of monitoring a sensor for sensing the flow speed of a medium. The invention further concerns an apparatus for carrying out that method. In order to be able to monitor the sensor, without providing redundant sensor, the flow speed of the medium, which is specified by the sensor, is correlated with at least one operating parameter of an instanation operated with the medium. For that purpose the apparatus according to the invention includes sensor for detecting the flow speed of a medium, am installation operated with the medium, which is specified by the sensor, with at least one operating parameter of the installation

Title of Invention

METHOD FOR MOINTORING A SENSOR

Abstract

The present invention concerns a method of monitoring a sensor for sensing the flow speed of a medium. The invention further concerns an apparatus for carrying out that method. In order to be able to monitor the sensor, without providing redundant sensor, the flow speed of the medium, which is specified by the sensor, is correlated with at least one operating parameter of an instanation operated with the medium. For that purpose the apparatus according to the invention includes sensor for detecting the flow speed of a medium, am installation operated with the medium, which is specified by the sensor, with at least one operating parameter of the installation

Full Text	The present invention concerns a method of monitoring a sensor for sensing the flow speed of a medium. The invention further concerns an apparatus for carrying out that method. It is already known from JP 11072502 to test the anemometer which is operating defectively in a process or to establish defective operation thereof. In that situation, the signal of the anemometer is evaluated by means of a computer and, with varying wind conditions, the evaluated data are compared and an error signal can be deduced there from. JP 57-198870 discloses a test device for anemometers, in which anemometers are tested under working conditions. US No 4 331 881 discloses how an anemometer can be used In a wind power installation, the signal from the anemometer being used to control the wind power installation. Sensors for monitoring flow speeds of media which are capable of flow have long been known, Quantitative flow speed meters are used in many variations, in dealing with liquids. Anemometers for example are used In the most widely varying structural configurations in relation to gaseous media which also include air. Those sensors are frequently exposed in situ to environmental conditions which can adversely effect reliable operability thereof. For example, anemometers arranged on wind power installations, depending on the weather, can certainly be subjected to icing. It will be easily appreciated that such an iced-up anemometer can scarcely still ascertain and deliver a correct value for the flow speed of the air. Redundancy does not afford a satisfactory solution here, as the redundantly provided anemometer is naturally also subjected to the icing effect. Therefore the object of the present invention is to develop a method and an apparatus of the kind set forth in the opening part of this specification, such that monitoring of a sensor is possible without the provision of redundant sensors. That is embodied in the method by the correlation of the flow speed of the medium, which is given by the sensor, with at least one operating parameter of an instaliation operated with the medium. In that respect the invention is based on the realisation that such an installation is operated not only on the basis of the data from that one sensor, but frequently operation is dependent on a plurality of parameters. In that manner, a given operating state occurs, independently of the sensor to be monitored but in dependence on the respective flow conditions. If now a characteristic operating parameter is correlated with the flow speed specified by the sensor, it is possible to deduce from that correlation an indication as to whether those values are in a plausible relationship with each other, that is to say whether the sensor is operating faultlessly. The object of the invention is further attained by an apparatus having a sensor for detecting the flow speed of a medium, en installation operated with the medium and a correlation device for correlating the flow speed of the medium, which is specified by the sensor, with at least one operating parameter of the installation. In a preferred development of the method the data from the sensor are correlated with a plurality of operating parameters in parallel or successive relationship. Parallel correlation of the data increases the reliability of the information provided about the sensor function. On the other hand however, depending on the operating state of the installation, it may be appropriate, according to the respective operating conditions involved, firstly to use a first operating parameter for the correlation procedure, but, with changing operating conditions, to make use of a second or further operating parameters for the correlation procedure in order to arrive at an assessment which is as reliable as possible. In a particularly preferred embodiment of the invention the correlation device is already integrated into the installation and thus can easily detect the operating parameters required for the correlation procedure and implement a suitable comparison. Advantageous developments of the invention are set forth in the appendant claims. An embodiment of the invention is described in greater detail hereinafter with reference to the drawings in which; Figure 1 shows a wind power installation; and Figure 2 shows characteristic curves of operating parameters of the wind power installation. Figure 1 shows a wind power installation comprising a pylon 10, a pod 12 arranged on the pylon 10, with a rotor having rotor blades 14 for driving a generator (not shown) arranged in the pod, the generator producing electrical power in dependence on the wind speed. Also provided on the pod 12 is an anemometer 16 for detecting the wind speed. As, in particular in winter, in corresponding weather conditions, the anemometer 16 can certainly suffer from icing and thus the wind speed can be incorrectly indicated, the anemometer 16 is monitored by the power produced by the wind power installation, which is dependent on the wind speed, being correlated with the reading from the anemometer 16. If the generated power of the wind power installation is higher than would be expected according to the wind speed ascertained by the anemometer 15, it is possible to deduce therefrom that the anemometer is not functioning faultlessly as the generated power could finally not be produced if the wind speed were not sufficient for that to happen. That relationship is shown once again in Figure 2 by means of characteristic curves. The characteristic curve 20 represents the variation in the power produced by the wind power installation in dependence on the wind speed. The abscissa is therefore identified by "V for the wind speed and the ordinate by "P" for power. As can be seen from the characteristic curve, the power rises with increasing wind speed until the nominal wind speed is reached at a point marked by 24 on the abscissa. From here on the wind power installation produces the nominal power. Thus, at least for the range from the origin of the curve to that switch-over point 24, the wind speed can be correlated with the power produced, in order to deduce from that correlation whether the anemometer 16 is functioning properly. After the nominal wind speed is reached however the curve 20 no longer provides any usable indication in regard to the correlation with the wind speed specified by the anemometer. Instead of the power characteristic curve however it is now possible to use the blade angle characteristic curve 22. From the moment of reaching the nominal wind speed and with a wind speed which further increases, more specifically the pitch angle of the rotor blades is altered. That is illustrated in the lower characteristic curve: here the abscissa is once again marked by V for the wind speed and the ordinate by "a" for the pitch angle of the rotor blades. It can be seen from the curve that the pitch angle decreases with increasing wind speed. Thus, after the curve goes beyond the switch-over point 24, it is possible, on the basis of the pitch angle "a" of the rotor blades, to determine whether the anemometer 16 is still specifying the correct wind speed. It will be appreciated that, instead of that successive use of a plurality of operating parameters, such use being dependent on the range of operation of the wind power installation, it is also possible for those parameters to be taken into consideration simultaneously. Therefore, as long as the wind speed is below the nominal wind speed, the electric power generated by the installation is used as the operating parameter and at the same time the pitch angle of the rotor blades 14 is investigated. After the curve has gone beyond the switch-over point 24 and thus the nominal wind speed has been exceeded, the pitch angle of the rotor blades 14 is now used and at the same time the power generated by the installation is taken into consideration. It will be appreciated that this method according to the invention and the apparatus can be applied not only in relation to wind power instailctions. In hydroelectric power stations, the amount of water flowing therethrough can be correlated with the electrical power generated. These methods and this apparatus can also be used even in internal combustion engines, in order for example to monitor the feed of fuel. Here the quantitative through-flow rate of the fuel can be correlated with the (mechanical) power produced. I CLAIM : 1. A method of monitoring a sensor for detecting a flow speed of a medium, comprising the steps of: detecting the flow speed of the medium by a sensor (16). comparing the flow speed of the medium detected by the sensor (16), with at least one operating parameter of a wind power installation or a hydroelectric power generator (10, 12, 14) driven by the medium to determine whether the sensor (16) operates correctly. 2. A method as claimed in claim 1, comprising the step of: providing a plurality of operating parameters simultaneously or successively for the comparison with the flow speed detected by the sensor (16). 3. Wind power installation, comprising: a plurality of rotor blades driven by a medium, a sensor (16) for detecting the flow speed of the medium and a comparison device for comparing the flow speed of the medium detected by the sensor (16) to at least one operating parameter of the wind power installation (10. 12, 14) to determine whether the sensor operates correctly. 4. Wind power mstallation as claimed in claim 3, wherein a sensor (16) is implemented as an anemometer. 5. Wind power installation as claimed in claim 4, wherein the comparison device is adapted to monitor the power produced by the wind power installation which is dependent on the wind speed such that a wind speed can be derived from the power produced by the wind power installation, wherein the wind speed derived from the power produced by the wind power installation is compared to the wind speed as detected by the anemometer. 6, Wind power installation as claimed in claims 4 or 5, wherein the comparison device is adapted to monitor the pitch angle of the rotor blades which depends on the wind speed, wherein the wind speed is derived from the pitch angle of the rotor blade and is compared to the wind speed as detected by the anemometer. 7. Wind power installation as claimed in claim 6, wherein the comparison device is adapted to monitor the power produced by the wind power installation to derive the wind speed corresponding to such power produced by the wind power mstallation until the power produced by the wind power installation corresponds to the nominal power, wherein the comparison device is adapted to monitor the pitch angle of the rotor blades when the power produced by the wind power installation has reached the nominal power, such that the wind speed is derived from the pitch angle of the rotor blades.

Full Text

The present invention concerns a method of monitoring a sensor for sensing the flow speed of a medium. The invention further concerns an apparatus for carrying out that method.
It is already known from JP 11072502 to test the anemometer which is operating defectively in a process or to establish defective operation thereof. In that situation, the signal of the anemometer is evaluated by means of a computer and, with varying wind conditions, the evaluated data are compared and an error signal can be deduced there from.
JP 57-198870 discloses a test device for anemometers, in which anemometers are tested under working conditions. US No 4 331 881 discloses how an anemometer can be used In a wind power installation, the signal from the anemometer being used to control the wind power installation.
Sensors for monitoring flow speeds of media which are capable of flow have long been known, Quantitative flow speed meters are used in many variations, in dealing with liquids. Anemometers for example are used In the most widely varying structural configurations in relation to gaseous media which also include air.
Those sensors are frequently exposed in situ to environmental conditions which can adversely effect reliable operability thereof. For example, anemometers arranged on wind power installations, depending on the weather, can certainly be subjected to icing. It will be easily appreciated that such an iced-up anemometer can scarcely still ascertain and deliver a correct value for the flow speed of the air. Redundancy does not afford a satisfactory solution here, as the redundantly provided anemometer is naturally also subjected to the icing effect.
Therefore the object of the present invention is to develop a method and an apparatus of the kind set forth in the opening part of this

specification, such that monitoring of a sensor is possible without the provision of redundant sensors.
That is embodied in the method by the correlation of the flow speed of the medium, which is given by the sensor, with at least one operating parameter of an instaliation operated with the medium. In that respect the invention is based on the realisation that such an installation is operated not only on the basis of the data from that one sensor, but frequently operation is dependent on a plurality of parameters. In that manner, a given operating state occurs, independently of the sensor to be monitored but in dependence on the respective flow conditions. If now a characteristic operating parameter is correlated with the flow speed specified by the sensor, it is possible to deduce from that correlation an indication as to whether those values are in a plausible relationship with each other, that is to say whether the sensor is operating faultlessly.
The object of the invention is further attained by an apparatus having a sensor for detecting the flow speed of a medium, en installation operated with the medium and a correlation device for correlating the flow speed of the medium, which is specified by the sensor, with at least one operating parameter of the installation.
In a preferred development of the method the data from the sensor are correlated with a plurality of operating parameters in parallel or successive relationship. Parallel correlation of the data increases the reliability of the information provided about the sensor function. On the other hand however, depending on the operating state of the installation, it may be appropriate, according to the respective operating conditions involved, firstly to use a first operating parameter for the correlation procedure, but, with changing operating conditions, to make use of a second or further operating parameters for the correlation procedure in order to arrive at an assessment which is as reliable as possible.
In a particularly preferred embodiment of the invention the correlation device is already integrated into the installation and thus can easily detect the operating parameters required for the correlation procedure and implement a suitable comparison.

Advantageous developments of the invention are set forth in the appendant claims.
An embodiment of the invention is described in greater detail hereinafter with reference to the drawings in which;
Figure 1 shows a wind power installation; and
Figure 2 shows characteristic curves of operating parameters of the wind power installation.
Figure 1 shows a wind power installation comprising a pylon 10, a pod 12 arranged on the pylon 10, with a rotor having rotor blades 14 for driving a generator (not shown) arranged in the pod, the generator producing electrical power in dependence on the wind speed. Also provided on the pod 12 is an anemometer 16 for detecting the wind speed.
As, in particular in winter, in corresponding weather conditions, the anemometer 16 can certainly suffer from icing and thus the wind speed can be incorrectly indicated, the anemometer 16 is monitored by the power produced by the wind power installation, which is dependent on the wind speed, being correlated with the reading from the anemometer 16. If the generated power of the wind power installation is higher than would be expected according to the wind speed ascertained by the anemometer 15, it is possible to deduce therefrom that the anemometer is not functioning faultlessly as the generated power could finally not be produced if the wind speed were not sufficient for that to happen.
That relationship is shown once again in Figure 2 by means of characteristic curves. The characteristic curve 20 represents the variation in the power produced by the wind power installation in dependence on the wind speed. The abscissa is therefore identified by "V for the wind speed and the ordinate by "P" for power. As can be seen from the characteristic curve, the power rises with increasing wind speed until the nominal wind speed is reached at a point marked by 24 on the abscissa. From here on the wind power installation produces the nominal power. Thus, at least for the range from the origin of the curve to that switch-over point 24, the wind speed can be correlated with the power produced, in order to deduce from that correlation whether the anemometer 16 is functioning properly.

After the nominal wind speed is reached however the curve 20 no longer provides any usable indication in regard to the correlation with the wind speed specified by the anemometer. Instead of the power characteristic curve however it is now possible to use the blade angle characteristic curve 22. From the moment of reaching the nominal wind speed and with a wind speed which further increases, more specifically the pitch angle of the rotor blades is altered. That is illustrated in the lower characteristic curve: here the abscissa is once again marked by V for the wind speed and the ordinate by "a" for the pitch angle of the rotor blades. It can be seen from the curve that the pitch angle decreases with increasing wind speed. Thus, after the curve goes beyond the switch-over point 24, it is possible, on the basis of the pitch angle "a" of the rotor blades, to determine whether the anemometer 16 is still specifying the correct wind speed.
It will be appreciated that, instead of that successive use of a plurality of operating parameters, such use being dependent on the range of operation of the wind power installation, it is also possible for those parameters to be taken into consideration simultaneously. Therefore, as long as the wind speed is below the nominal wind speed, the electric power generated by the installation is used as the operating parameter and at the same time the pitch angle of the rotor blades 14 is investigated. After the curve has gone beyond the switch-over point 24 and thus the nominal wind speed has been exceeded, the pitch angle of the rotor blades 14 is now used and at the same time the power generated by the installation is taken into consideration.
It will be appreciated that this method according to the invention and the apparatus can be applied not only in relation to wind power instailctions. In hydroelectric power stations, the amount of water flowing therethrough can be correlated with the electrical power generated.
These methods and this apparatus can also be used even in internal combustion engines, in order for example to monitor the feed of fuel. Here the quantitative through-flow rate of the fuel can be correlated with the (mechanical) power produced.

I CLAIM :
1. A method of monitoring a sensor for detecting a flow speed of a
medium, comprising the steps of:
detecting the flow speed of the medium by a sensor (16).
comparing the flow speed of the medium detected by the sensor (16), with at least
one operating parameter of a wind power installation or a hydroelectric power generator (10, 12, 14) driven by the medium to determine whether the sensor (16) operates correctly.
2. A method as claimed in claim 1, comprising the step of:
providing a plurality of operating parameters simultaneously or successively for the comparison with the flow speed detected by the sensor (16).
3. Wind power installation, comprising:
a plurality of rotor blades driven by a medium, a sensor (16) for detecting the flow speed of the medium and a comparison device for comparing the flow speed of the medium detected by the sensor (16) to at least one operating parameter of the wind power installation (10. 12, 14) to determine whether the sensor operates correctly.
4. Wind power mstallation as claimed in claim 3, wherein a sensor (16) is implemented as an anemometer.
5. Wind power installation as claimed in claim 4, wherein the comparison device is adapted to monitor the power produced by the wind power installation which is dependent on the wind speed such that a wind speed can be derived from the power

produced by the wind power installation, wherein the wind speed derived from the power produced by the wind power installation is compared to the wind speed as detected by the anemometer.
6, Wind power installation as claimed in claims 4 or 5, wherein the
comparison device is adapted to monitor the pitch angle of the rotor blades
which depends on the wind speed, wherein the wind speed is derived from the
pitch angle of the rotor blade and is compared to the wind speed as detected by
the anemometer.
7. Wind power installation as claimed in claim 6, wherein the comparison
device is adapted to monitor the power produced by the wind power installation
to derive the wind speed corresponding to such power produced by the wind
power mstallation until the power produced by the wind power installation
corresponds to the nominal power, wherein the comparison device is adapted to
monitor the pitch angle of the rotor blades when the power produced by the
wind power installation has reached the nominal power, such that the wind
speed is derived from the pitch angle of the rotor blades.

Documents:

1150-chenp-2004 abstract duplicate.pdf

1150-chenp-2004 abstract.pdf

1150-chenp-2004 claims duplicate.pdf

1150-chenp-2004 claims.pdf

1150-chenp-2004 correspondence others.pdf

1150-chenp-2004 correspondence po.pdf

1150-chenp-2004 description (complete) duplicate.pdf

1150-chenp-2004 description (complete).pdf

1150-chenp-2004 drawings duplicate.pdf

1150-chenp-2004 drawings.pdf

1150-chenp-2004 form-1.pdf

1150-chenp-2004 form-19.pdf

1150-chenp-2004 form-26.pdf

1150-chenp-2004 form-3.pdf

1150-chenp-2004 form-5.pdf

1150-chenp-2004 pct search report.pdf

1150-chenp-2004 pct.pdf

1150-chenp-2004 petition.pdf

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Patent Number

203552

Indian Patent Application Number

1150/CHENP/2004

PG Journal Number

09/2007

Publication Date

02-Mar-2007

Grant Date

21-Nov-2006

Date of Filing

26-May-2004

Name of Patentee

SHRI. 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

F03D 11/00

PCT International Application Number

PCT/EP2002/012721

PCT International Filing date

2002-11-14

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	101 57 759.1	2001-11-27	Germany