System and method for detecting ice on a wind turbine rotor blade

A system and method for detecting ice on a rotor blade of a wind turbine are disclosed. In one embodiment, the method may include pitching the rotor blade across a range of pitch angles, monitoring an ice-related parameter of the wind turbine as the rotor blade is pitched and comparing the monitored ice-related parameter to a predetermined baseline profile for the ice-related parameter.

FIELD OF THE INVENTION

The present subject matter relates generally to wind turbines and, more particularly, to a system and method for detecting ice on a wind turbine rotor blade.

BACKGROUND OF THE INVENTION

Generally, a wind turbine includes a tower, a nacelle mounted on the tower, and a rotor coupled to the nacelle. The rotor typically includes a rotatable hub and a plurality of rotor blades coupled to and extending outwardly from the hub. Each rotor blade may be spaced about the hub so as to facilitate rotating the rotor to enable kinetic energy to be transferred from the wind into usable mechanical energy, and subsequently, electrical energy.

Under some atmospheric conditions, ice may be buildup or otherwise accumulate on the rotor blades of a wind turbine. As the ice layer accumulating on a rotor blade becomes increasingly thicker, the aerodynamic surface of the blade is modified, thereby resulting in diminished aerodynamic performance. Moreover, ice accumulation significantly increases the weight of a rotor blade, which can lead to structural damage as an increased amount of bending moments and/or other rotational forces act on the rotor blade. In addition, when there is a differential in the amount of ice accumulating on each of the rotor blades, a mass imbalance may occur that can cause significant damage to a wind turbine.

Due to the disadvantages associated with ice accumulation, a wind turbine may be shutdown when it is believed that ice has accumulated on the surface of one or more of the rotor blades. Operation of the wind turbine may then be restarted after it can be verified that ice is no longer present on the rotor blades. Accordingly, upon shutdown of a wind turbine for ice accumulation, each rotor blade must be inspected to determine whether ice is actually and/or is still present on the blades. Conventionally, this requires that each blade be visually inspected from a location on the ground. However, due to the risk of falling ice, the service worker(s) performing the visual inspection must be located a safe distance away from the wind turbine. As such, it is often difficult to visually detect ice accumulation on the rotor blades. Moreover, such a visual inspection of the rotor blade blades typically takes a significant amount of time, which may unnecessarily increase that amount of time that a wind turbine is shutdown to check for ice accumulations.

Accordingly, a system and method that allows for the accurate and efficient detection of ice on a wind turbine rotor blade would be welcomed in the technology.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, the present subject matter is directed to a method for detecting ice on a rotor blade of a wind turbine. The method may generally include pitching the rotor blade across a range of pitch angles, monitoring an ice-related parameter of the wind turbine as the rotor blade is pitched and comparing the monitored ice-related parameter to a predetermined baseline profile for the ice-related parameter.

In another aspect, the present subject matter is directed to a system for detecting ice on a rotor blade of a wind turbine. The system may generally include a pitch adjustment mechanism configured to pitch the rotor blade and a sensor configured to monitor an ice-related parameter of the wind turbine as the rotor blade is pitched. In addition, the system may include a controller communicatively coupled to the pitch adjustment mechanism and the sensor. The controller may be configured to control the pitch adjustment mechanism so that the rotor blade is pitched across a range of pitch angles. Moreover, the controller may be configured to receive signals from the sensor related to the ice-related parameter and compare the ice-related parameter to a predetermined baseline profile to determine if any ice is present on the rotor blade.

DETAILED DESCRIPTION OF THE INVENTION

In general, the present subject matter is directed to a system and method for detecting ice on a wind turbine rotor blade. Specifically, the disclosed system and method provide a means for detecting ice accumulations on a rotor blade while a wind turbine is not operating. For example, in several embodiments, upon shutdown of a wind turbine, each rotor blade may be pitched across a range of pitch angles while an ice-related parameter of the wind turbine is monitored. The monitored ice-related parameter may then be compared to a predetermined baseline profile for such parameter in order to determine whether ice is present on any of the rotor blades.

The wind turbine10may also include a turbine control system or turbine controller26centralized within the nacelle16. In general, the turbine controller26may comprise a computer or other suitable processing unit. Thus, in several embodiments, the turbine controller26may include suitable computer-readable instructions that, when implemented, configure the controller26to perform various different functions, such as receiving, transmitting and/or executing wind turbine control signals. As such, the turbine controller26may generally be configured to control the various operating modes (e.g., start-up or shut-down sequences) and/or components of the wind turbine10. For example, the controller26may be configured to adjust the blade pitch or pitch angle of each rotor blade22(i.e., an angle that determines a perspective of the blade22with respect to the direction of the wind) about its pitch axis28in order to control the rotational speed of the rotor blade22and/or the power output generated by the wind turbine10. For instance, the turbine controller26may control the pitch angle of the rotor blades22, either individually or simultaneously, by transmitting suitable control signals to one or more pitch drives or pitch adjustment mechanisms30(FIG. 2) of the wind turbine10. During operation of the wind turbine10, the controller26may generally control each pitch adjust mechanism30in order to alter the pitch angle of each rotor blade22between 0 degrees (i.e., a power position of the rotor blade22) and 90 degrees (i.e., a feathered position of the rotor blade22).

Referring now toFIG. 2, a simplified, internal view of one embodiment of the nacelle16of the wind turbine10shown inFIG. 1is illustrated. As shown, a generator24may be disposed within the nacelle16. In general, the generator24may be coupled to the rotor18for producing electrical power from the rotational energy generated by the rotor18. For example, as shown in the illustrated embodiment, the rotor18may include a rotor shaft32coupled to the hub20for rotation therewith. The rotor shaft32may, in turn, be rotatably coupled to a generator shaft34of the generator24through a gearbox36. As is generally understood, the rotor shaft32may provide a low speed, high torque input to the gearbox36in response to rotation of the rotor blades22and the hub20. The gearbox36may then be configured to convert the low speed, high torque input to a high speed, low torque output to drive the generator shaft34and, thus, the generator24.

Additionally, the turbine controller26may also be located within the nacelle16. As is generally understood, the turbine controller26may be communicatively coupled to any number of the components of the wind turbine10in order to control the operation of such components. For example, as indicated above, the turbine controller26may be communicatively coupled to each pitch adjustment mechanism30of the wind turbine10(one of which is shown) to facilitate rotation of each rotor blade22about its pitch axis28.

In general, each pitch adjustment mechanism30may include any suitable components and may have any suitable configuration that allows the pitch adjustment mechanism30to function as described herein. For example, in several embodiments, each pitch adjustment mechanism30may include a pitch drive motor38(e.g., any suitable electric motor), a pitch drive gearbox40, and a pitch drive pinion42. In such embodiments, the pitch drive motor38may be coupled to the pitch drive gearbox40so that the pitch drive motor38imparts mechanical force to the pitch drive gearbox40. Similarly, the pitch drive gearbox40may be coupled to the pitch drive pinion42for rotation therewith. The pitch drive pinion42may, in turn, be in rotational engagement with a pitch bearing44coupled between the hub20and a corresponding rotor blade22such that rotation of the pitch drive pinion42causes rotation of the pitch bearing44. Thus, in such embodiments, rotation of the pitch drive motor38drives the pitch drive gearbox40and the pitch drive pinion42, thereby rotating the pitch bearing44and the rotor blade22about the pitch axis28.

In alternative embodiments, it should be appreciated that each pitch adjustment mechanism30may have any other suitable configuration that facilitates rotation of a rotor blade22about its pitch axis28. For instance, pitch adjustment mechanisms30are known that include a hydraulic or pneumatic driven device (e.g., a hydraulic or pneumatic cylinder) configured to transmit rotational energy to the pitch bearing44, thereby causing the rotor blade22to rotate about its pitch axis28. Thus, in several embodiments, instead of the electric pitch drive motor38described above, each pitch adjustment mechanism30may include a hydraulic or pneumatic driven device that utilizes fluid pressure to apply torque to the pitch bearing44.

Referring still toFIG. 2, the wind turbine may also include a plurality of sensors46,48for monitoring one or more parameters and/or conditions of the wind turbine10. As used herein, a parameter or condition of the wind turbine10is “monitored” when a sensor46,48is used to determine its present value. Thus, the term “monitor” and variations thereof are used to indicate that the sensors46,48need not provide a direct measurement of the parameter and/or condition being monitored. For example, the sensors46,48may be used to generate signals relating to the parameter and/or condition being monitored, which can then be utilized by the turbine controller26or other suitable device to determine the actual parameter and/or condition.

Thus, in several embodiments of the present subject matter, the wind turbine10may include one or more sensors46,48configured to monitor the amount of torque required to pitch each rotor blade22about its pitch axis28. Specifically, in several embodiments, the wind turbine10may include one or more sensors46configured to transmit signals to the turbine controller26relating directly to the amount of torque generated by each pitch adjustment mechanism30. For example, the sensor(s)46may comprise one or more torque sensors coupled to a portion of the pitch drive motor38, the pitch gearbox40and/or the pitch drive pinion42in order to monitor the torque generated by each pitch adjustment mechanism30. Alternatively, the sensor(s)46may comprise one or more suitable sensors configured to transmit signals to the turbine controller26relating indirectly to the amount of torque generated by each pitch adjustment mechanism30. For instance, in embodiments in which the pitch drive mechanism30is electrically driven, the sensor(s)46may comprise one or more current sensors configured to detect the electrical current supplied to the pitch drive motor38of each pitch adjustment mechanism30. Similarly, in embodiments in which the pitch adjustment mechanism30is hydraulically or pneumatically driven, the sensor(s)42may comprise one or more suitable pressure sensors configured to detect the pressure of the fluid within the hydraulically or pneumatically driven device. In such embodiments, the turbine controller26may generally include suitable computer-readable instructions (e.g., in the form of suitable equations, transfer functions, models and/or the like) that, when implemented, configure the controller26to correlate the current input or the pressure input to the torque generated by each pitch adjustment mechanism30.

In addition to the sensor(s)46described above or as an alternative thereto, the wind turbine10may also include one or more sensors48configured to monitor the torque required to pitch each rotor blade22by monitoring the force(s) present at the pitch bearing44(e.g., the force(s) present at the interface between the pitch drive pinion42and the pitch bearing44). For example, the sensor(s)48may comprise one or more pressure sensors and/or any other suitable sensors configured to transmit signals relating to the forces present at the pitch bearing44. In such an embodiment, similar to that described above, the turbine controller26may generally include suitable computer-readable instructions (e.g., in the form of suitable equations, transfer functions, models and the like) that, when implemented, configure the controller26to correlate the force(s) present at the pitch bearing44to the torque required to pitch each rotor blade22.

It should be appreciated that the wind turbine10may also include various other sensors for monitoring any other suitable parameters and/or conditions of the wind turbine10. For example, the wind turbine10may include sensors for monitoring the pitch angle of each rotor blade22, any bending moments on the rotor blades22, the speed of the rotor18and/or the rotor shaft32, the speed of the generator24and/or the generator shaft34, the torque on the rotor shaft32and/or the generator shaft34, the wind speed and/or wind direction and/or any other suitable parameters and/or conditions.

Referring now toFIG. 3, there is illustrated a block diagram of one embodiment of suitable components that may be included within the turbine controller26in accordance with aspects of the present subject matter. As shown, the turbine controller26may include one or more processor(s)50and associated memory device(s)52configured to perform a variety of computer-implemented functions (e.g., performing the methods, steps, calculations and the like disclosed herein). As used herein, the term “processor” refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. Additionally, the memory device(s)52may generally comprise memory element(s) including, but not limited to, computer readable medium (e.g., random access memory (RAM)), computer readable non-volatile medium (e.g., a flash memory), a floppy disk, a compact disc-read only memory (CD-ROM), a magneto-optical disk (MOD), a digital versatile disc (DVD) and/or other suitable memory elements. Such memory device(s)52may generally be configured to store suitable computer-readable instructions that, when implemented by the processor(s)50, configure the turbine controller26to perform various functions including, but not limited to, transmitting suitable control signals to one or more of the pitch adjustment mechanisms30, monitoring various parameters and/or conditions of the wind turbine10and various other suitable computer-implemented functions.

Additionally, the turbine controller26may also include a communications module54to facilitate communications between the controller26and the various components of the wind turbine10. For instance, the communications module54may serve as an interface to permit the turbine controller26to transmit control signals to each pitch adjustment mechanism30for controlling the pitch angle of the rotor blades22. Moreover, the communications module54may include a sensor interface56(e.g., one or more analog-to-digital converters) to permit signals transmitted from the sensors46,48of the wind turbine10to be converted into signals that can be understood and processed by the processors50.

It should be appreciated that the sensors46,48may be communicatively coupled to the communications module54using any suitable means. For example, as shown inFIG. 3, each sensor46,48is coupled to the sensor interface56via a wired connection. However, in other embodiments, the sensors46,48may be coupled to the sensor interface56via a wireless connection, such as by using any suitable wireless communications protocol known in the art.

Referring now toFIG. 4, there is illustrated a flow diagram of one embodiment of a method100for detecting ice on a wind turbine rotor blade. As shown, the method100generally includes pitching a rotor blade across a range of pitch angles102, monitoring an ice-related parameter of the wind turbine as the rotor blade is pitched104and comparing the monitored ice-related parameter to a predetermined baseline profile for the ice-related parameter106.

In general, the disclosed method100provides a simple and accurate test for detecting ice accumulation on a rotor blade22. Specifically, the disclosed method100provides a test for detecting ice accumulation on a rotor blade22while a wind turbine10is not operating (i.e., when the rotor18is not rotating). For example, as indicated above, wind turbines10are often shutdown when it is believed that ice is accumulating on one or more of the rotor blades22in order to prevent damage to the rotor blades22and/or to decrease the likelihood of damage/injury that may be caused by ice falling from the rotor blades22. Moreover, when a wind turbine10is shutdown due to the belief or actual presence of ice accumulations on one or more of the rotor blades22, operation of the wind turbine10is not typically restarted until it has been verified that ice is no longer present on the blade(s)22. Accordingly, the disclosed method100may allow for the presence of ice to be quickly and accurately detected, thereby minimizing downtime of the wind turbine10.

In several embodiments, it should be appreciated that the disclosed method100may be performed automatically by the turbine controller26. For example, the turbine controller26may be provided with suitable computer-readable instructions that, when implemented, configure the controller26to transmit control signals to the pitch adjustment mechanisms30in order to pitch the rotor blades22across a range of pitch angles. Moreover, the turbine controller26may be configured to monitor an ice-related parameter of the wind turbine10as each rotor blade22is pitched and, based on the ice-related parameter, determine whether any ice has accumulated on the blades22. For instance, the controller26may be configured to compare the monitored ice-related parameter to a predetermined baseline profile for such parameter in order to determine whether ice is present on the rotor blade(s)22.

As shown inFIG. 4, in102, one or more of the rotor blades22may be pitched across a range of pitch angles. As indicated above, the disclosed method100is generally designed as a non-operating ice detection test. Thus, in several embodiments, the wind turbine10may be shutdown prior to pitching the rotor blade(s)22across the range of pitch angles. For example, each of the rotor blades22may be initially pitched to the feathered position (i.e., a 90 degree pitch angle) in order to stop rotation of the rotor18and, thus, halt operation of the wind turbine10.

Upon shutdown of the wind turbine10, the rotor blades22may then be pitched across the range of pitch angles using the pitch adjustment mechanisms30described above. In several embodiments, the turbine controller26may be configured to control the pitch adjustment mechanisms30individually such that the rotor blades22are pitched one at a time. For instance, the controller26may be adapted to initially transmit suitable control signals to one of the pitch adjustment mechanisms30so that only the rotor blade22controlled by such pitch adjustment mechanism30is pitched across the range of pitch angles. After pitching the rotor blade22and returning it to the feathered position, the controller26may then transmit suitable control signals to one of the other pitch adjustment mechanisms30so that another rotor blade22is pitched across the range of pitch angles. By pitching each of the rotor blades22in this manner, the rotor blades22not being tested may be maintained at the feathered position, thereby preventing the rotor18from rotating.

In general, each rotor blade22may be pitched across any suitable range of pitch angles during the performance of the disclosed method100. As will be described in greater detail below, the pitching of each rotor blade22is generally performed so that an ice-related parameter of the wind turbine10may be monitored as the blade22is pitched, thereby providing an indication of whether ice has accumulated on the blade22. Thus, it should be appreciated that the angular range across which each rotor blade22is pitched may generally vary depending on numerous factors including, but not limited to, the configuration of each rotor blade22, the configuration of the wind turbine10, the particular ice-related parameter being monitored and/or the amount of data needed regarding the ice-related parameter in order to provide an accurate estimation of whether ice is present on a rotor blade22. However, in several embodiments, each rotor blade22may generally be pitched at least 45 degrees from the feathered position, such as by pitching each rotor blade at least 90 degrees from the feathered position or at least 180 degrees from the feathered position and all other subranges therebetween. For instance, in one embodiment, each rotor blade22may be pitched a total of about 180 degrees, such as by pitching each rotor blade22from the feathered position to the power position and back to the feathered position. In another embodiment, each rotor blade22may be pitched a full revolution (i.e., 360 degrees) in a clockwise or counter-clockwise direction about the pitch axis28.

Referring still toFIG. 4, in104, an ice-related parameter of the wind turbine10is monitored as the rotor blade22is pitched across the range of pitch angles. As used herein, the term “ice-related parameter” generally refers to any parameter and/or condition of a wind turbine10that may vary as a rotor blade22is pitched depending on whether ice is present on the blade22. For instance, in several embodiments, the ice-related parameter may correspond to the amount of torque required to pitch each rotor blade22across the range of pitch angles. Specifically, as indicated above, ice accumulation on a rotor blade22may increase its weight and may also alter its mass distribution. Thus, the torque required to pitch a rotor blade22having no ice accumulation may generally vary from the torque required to pitch the same rotor blade22having ice accumulated thereon.

As indicated above, the torque required to pitch each rotor blade22may be monitored using one or more suitable sensors46,48. For example, the torque generated by each pitch adjustment mechanism30may be monitored directly using suitable torque sensors or indirectly using various other suitable sensors (e.g., current sensors and/or pressure sensors configured monitor the current input and/or pressure input to the pitch adjustment mechanism30). Alternatively, the torque required to pitch each rotor blade may be monitored by monitoring the force present at the pitch bearing44of the wind turbine10.

In other embodiments, the ice-related parameter may correspond to the amount of time required to pitch each rotor blade22across the range of pitch angles. For example, in one embodiment, each pitch adjustment mechanism30may be configured to pitch each rotor blade22with a constant torque. As such, due to the increase in weight and/or the varied mass distribution caused by ice accumulations, the time required to pitch each rotor blade22may vary depending on the presence of ice. In such embodiments, the turbine controller26may generally be configured to monitor the time required to pitch each rotor blade22. For example, the controller26may be provided with suitable computer readable instructions and/or suitable digital hardware (e.g., a digital counter) that configures the controller26to monitor the amount of time elapsed while each blade22is pitched across the range of pitch angles.

In even further embodiments, it should be appreciated that the ice-related parameter may correspond to any other suitable parameter and/or condition of the wind turbine10that provides an indication of the presence of ice on a rotor blade22. For example, the ice-related parameter may correspond to bending moments and/or other stresses acting on the rotor blade22, as such bending moments and/or other stresses may generally vary due to the increased weight caused by ice accumulations. In such an embodiment, one or more strain gauges and/or other suitable sensors may be installed within the rotor blade22to permit such bending moments and/or other stresses to be monitored.

Referring still toFIG. 4, in106, the monitored ice-related parameter may be compared to a predetermined baseline profile in order to determine whether ice is actually present on the rotor blade22. In general, the baseline profile may correspond to a predetermined set of reference values that are equal to the anticipated or actual values of the ice-related parameter being monitored assuming no ice is present on the rotor blade22being pitched. For example, when the ice-related parameter corresponds to the amount of torque required to pitch each rotor blade22, the baseline profile may comprise a predetermined set of values equal to the amount of torque required to pitch each rotor blade22across the range of pitch angles when no ice is present on the blade22. Accordingly, variations from the baseline profile may generally provide an indication of ice accumulations on the rotor blade22.

It should be appreciated that the baseline profile for a particular ice-related parameter may generally vary from wind turbine10to wind turbine10and/or from rotor blade22to rotor blade22. Thus, in several embodiments, individual baseline profiles for the ice-related parameter being monitored may be determined for each rotor blade22. In general, the baseline profiles for the rotor blades22may be determined using any suitable means and/or method known in the art. For instance, in one embodiment, the baseline profile of each rotor blade22may be determined experimentally, such as by individually pitching each rotor blade22across the range of pitch angles when it is known that no ice is present on the blade22and monitoring the ice-related parameter of the blade22to establish the baseline profile. In another embodiment, the baseline profile for each rotor blade22may be modeled or determined mathematically, such as by calculating the baseline profiles based on, for example, the configuration of each rotor blade22, the specifications of each pitch adjustment mechanism30and/or the anticipated variation in the ice-related parameter due to the presence of ice.

It should also be appreciated that, in several embodiments, the baseline profile established for a particular rotor blade22may be continuously updated. Specifically, due to wear and tear on wind turbine components and other factors, the baseline profile for a rotor blade22may vary over time. For example, wear and tear on one of the pitch bearings44may significantly affect the baseline profile for the corresponding rotor blade22. Thus, in several embodiments, the turbine controller26may be configured to continuously adjust the baseline profile for each rotor blade22based on calculated and/or anticipated turbine component wear and/or on any other factors that may cause the baseline profile to vary over time.

Referring now toFIG. 5, one example of a baseline torque profile110for the torque required to pitch a rotor blade22across a range of pitch angles is illustrated in accordance with aspects of the present subject matter. Specifically, the baseline torque profile110is charted for a rotor blade22having no ice accumulation for pitch angles extending from the feathered position to the power position and back to the feathered position. Thus, as the rotor blade22is pitched across such pitch angles during the performance of the disclosed method100, the torque required to pitch the blade22may be continuously compared to the baseline torque profile110to determine if any ice has accumulated on the rotor blade22.

Additionally, in several embodiments, a predetermined tolerance or percent variation112may be incorporated into the baseline profile110to accommodate slight deviations that may result from sensor inaccuracies, component wear and/or other factors that are not associated with ice accumulations on a rotor blade22. For example, as shown inFIG. 5, a range of torque values for each pitch angle may be banded between the baseline torque profile110and line114that corresponds to an allowable percent variation112from the baseline torque profile110. Thus, as long as the monitored torque values for the rotor blade22remain within the area defined between the baseline torque profile110and line114, it may be assumed that no ice is present on the blade22. However, if any of the monitored torque values fall outside the allowable percent variation112, it may be assumed that ice has accumulated on the rotor blade22and operation of the wind turbine10may be delayed until it is determined that the ice is no longer present on the blade22. For example, the turbine controller26may be configured to wait a predetermined amount of time and then re-perform the disclosed method10in order to determine if the ice previously detected has melted away or has otherwise been removed from the rotor blade22.

It should be appreciated that the allowable percent variation112from the baseline profile110may generally vary based on numerous factors including, but not limited to, the configuration of the rotor blade,22the accuracy of any sensors46,48being utilized and/or the actual and/or anticipated wear on any relevant wind turbine components (e.g., the pitch bearing44). However, it is well within the skill of one of ordinary skill in the art to determine a suitable percent variation112for each baseline profile110based on the factors described above and/or any other suitable factors that may cause variations in the baseline profile110and/or the ice-related parameter being monitored. It should also be appreciated that the allowable percent variation112need not only correspond to an increase in the magnitude of the torque required to pitch the blade22as shown inFIG. 4. For example, in other embodiments, the allowable percent variation112may correspond to a plus/minus variation in the baseline torque profile110or a decrease increase in the magnitude of the torque required to pitch the blade22.

Referring now toFIG. 6, an example of a baseline time profile210for the amount of time required to pitch a rotor blade22across a range of pitch angles at a constant torque is illustrated in accordance with aspects of the present subject matter. Specifically, the baseline time profile210is charted for a rotor blade22having no ice accumulation for pitch angles extending from the feathered position to the power position and back to the feathered position. Thus, as the rotor blade22is pitched across such pitch angles during the performance of the disclosed method100, the amount of time required to pitch the blade22may be continuously compared to the baseline time profile210to determine if any ice has accumulated on the rotor blade22.

Additionally, similar to that shown inFIG. 5, in several embodiments, a predetermined tolerance or percent variation212may be incorporated into the baseline profile210. For example, as shown inFIG. 6, a range of time values for each pitch angle may be banded between the baseline time profile210and line214that corresponds to an allowable percent variation212from the baseline time profile210. Thus, as long as the monitored time values remain within the area defined between the baseline time profile210and line214, it may be assumed that no ice is present on the rotor blade22. However, if any of the monitored time values fall outside the allowable percent variation212, it may be assumed that ice has accumulated on the rotor blade22and operation of the wind turbine10may be delayed until it is determined that the ice is no longer present on the blade22(e.g., by re-performing the disclosed method100after a predetermined amount of time).

As indicated above, it should be appreciated that the present subject matter is also directed to a system for detecting ice on a wind turbine rotor blade22. Thus, in several embodiments, the system may generally include a pitch adjustment mechanism30configured to pitch the rotor blade22about its pitch axis28and one or more sensors46,48configured to monitor an ice-related parameter of the wind turbine10as the blade22is pitched. Additionally, the system may include a controller26communicatively coupled to the pitch adjustment mechanism30and the sensor(s)46,48. As described above, the controller26may be configured to control the pitch adjustment mechanism30so that the rotor blade22is pitched across a range of pitch angles. In addition, the controller26may also be configured to receive signals from the sensor(s)46,48related to the ice-related parameter being monitored and compare such monitored parameter to a predetermined baseline profile to determine if any ice is present on the rotor blade22.