Patent Publication Number: US-2012045330-A1

Title: System and method for monitoring and controlling physical structures

Description:
BACKGROUND 
     Embodiments presented herein relate generally to monitoring and controlling systems, and more specifically to a system for monitoring and controlling a physical structure. 
     Physical structures such as wind turbines are known as an important source for renewable energy. Wind turbines convert wind energy into electrical energy. Specifically, wind blowing over the blades causes the blades to produce ‘lift’ and thus rotate about a shaft. Further, the shaft drives a generator which produces electrical energy. Typically, the wind turbines are exposed to variable aerodynamic load due to varying wind conditions. Moreover, the wind turbines are also exposed to unpredictable harsh weather conditions. In such instances, it is desirable to know the wind turbine components&#39; spatial behavior, such as overall bending and twisting along the blades length, tower top displacement and vibration, yaw angle, and the like. These sensing feedbacks may be used for monitoring the physical health of the wind turbine components, which upon going unnoticed may lead to catastrophic failure of the wind turbine. Also, these sensing feedbacks may be used for controlling the wind turbine&#39;s operating parameters for achieving better efficiency (energy production) of the wind turbines. 
     This problem is partly mitigated by wind turbine monitoring systems which provide wind turbine sensing feedback, and help in detecting impending wind turbine component failure. Some known wind turbine monitoring systems such as outboard sensor systems may be used to monitor mechanical stress on the blades of the wind turbine. The outboard sensor systems utilize sensors installed on the blades of the wind turbine. For example, fiber bragg grating (FBG) strain sensors are generally mounted outside the blades of the wind turbine for measuring stain occurring on the blades. However, such sensors are subjected to harsh weather conditions, such as high wind speeds, rainfall, snow, hail and the like, which may shorten the life of the sensors. Further, the outboard sensor system also has low spatial resolution limited by the number of the sensors that may be installed on the blades of the wind turbine. 
     Moreover, a system of triaxial accelerometers embedded in each blade of the turbine may be used for measuring the operating frequencies of the turbine blades and may alert when a significant deviation from normal operating parameters is monitored, either from excessive stress, or blade damage. However, this approach also has a low spatial resolution and a limitation on the low-frequency response. 
     Therefore, there is a need for a monitoring and controlling system that overcomes these and other problems associated with known solutions. 
     BRIEF DESCRIPTION 
     A system includes a light source adapted to generate light pulses. The system also includes a beam scanner coupled with the light source. The beam scanner is adapted to scan the light pulses over a predefined capture area of a physical structure. The system further includes a photo-detector adapted to receive backscattered light pulses from the physical structure and subsequently provide a signal corresponding to each of the light pulse. The system further includes a pre-processing module to adjust a threshold of the signal based on a normalized value of a detected peak value of the signal. The system also includes an association module to associate a time of flight with each of the received backscattered light pulse. The system further includes an image generator to generate an image of the physical structure based on the time of flight associated with each of the received light pulse. The system further includes an image comparator to compare the generated image with at least one known image of the physical structure. The image comparator is adapted to compare the images based on the time of flight associated with each of the received light pulses. The system further includes a health indicator module for generating a health profile of the physical structure based at least in part on the comparison. 
     A system for controlling a wind turbine includes a light source adapted to generate light pulses. The system also includes a beam scanner coupled with the light source. The beam scanner is adapted to scan the light pulses over a predefined capture area of the wind turbine. The system further includes a photo-detector adapted to receive backscattered light pulses from the wind turbine and subsequently provide a signal corresponding to each of the light pulse. The system further includes a pre-processing module to adjust a threshold of the signal based on a normalized value of a detected peak value of the signal. The system also includes an association module to associate a time of flight with each of the received backscattered light pulse. The system further includes an image generator to generate an image of the wind turbine based on the time of flight associated with each of the received light pulse. The system further includes an image comparator to compare the generated image with at least one known image of the wind turbine. The image comparator is adapted to compare the images based on the time of flight associated with each of the received light pulses. The system further includes a health indicator module for generating a health profile of the wind turbine based at least in part on the comparison. The system also includes a control unit adapted to change one or more parameters of the wind turbine based at least in part on the health profile of the wind turbine. 
     A method of controlling a wind turbine includes sending a scanned light beam, constituted by light pulses over a pre-defined capture area of the wind turbine. The method also includes receiving backscattered light beam from the wind turbine. The method further includes generating a digitized voltage signal corresponding to each of the received backscattered light pulses. The method further includes detecting a peak value of the voltage signal. The method further includes adjusting a threshold of the voltage signal based on a normalized value of the detected peak value of the voltage signal. The method further includes calculating a time of flight corresponding to each of the received backscattered light pulses based at least in part on the adjusted threshold. The method also includes associating the calculated time of flight with each of the received backscattered light pulses. The method further includes generating an image of the wind turbine based on the associated time of flight with each of the received backscattered light pulses. The method further includes comparing the generated image with at least one known image of the wind turbine. The method further includes generating a health profile of the wind turbine based at least in part on the comparison. The method further includes controlling one or more parameters of the wind turbine based at least in part on the health profile of the wind turbine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified block diagram of a system for monitoring health of a physical structure, according to one embodiment; 
         FIG. 2  illustrates an environment for controlling a wind turbine using the system of  FIG. 1 , according to one embodiment; 
         FIG. 3  is a simplified block diagram of a system for controlling the wind turbine, according to another embodiment; and 
         FIG. 4  is a flowchart of an example process for controlling the wind turbine, according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a system  100  for monitoring the health of a physical structure  200 , according to one embodiment. For example, the system  100  may be used in conjunction with the physical structure  200 , which may be a wind turbine, a tower, a terrestrial structure, and an aerial structure, for monitoring the health thereof. 
     The system  100  may include a light source  110 . The light source  110  may be adapted to generate a light beam, constituted by short light pulses. In an exemplary embodiment, the light source  110  may be a laser source, which is adapted to generate a laser beam. The terms “light beam” and “light pulses” may be hereinafter alternatively referred to as “light beam” and “light pulses.” 
     The light source  110  may be a gas laser, a chemical laser, a dye laser, a metal-vapor laser, a solid-state laser, a semiconductor laser and the like. Further, in an exemplary embodiment, the light source  110  may be adapted to generate short light pulses of less than or equal to lns in duration. The system  100  may also include a light controller  112  coupled with the light source  110 . The light controller  112  may be adapted to modulate an intensity of the light pulses from the light source  110 . 
     The system  100  may further include a beam scanner  120  coupled with the light source  110 . The beam scanner  120  may be a high speed scanner adapted to scan the light pulses generated by the light source  110 . In one embodiment, the beam scanner  120  may employ an electro-optic deflector for deflecting the light pulses to achieve a high speed scanning rate. The beam scanner  120 , and particularly, the electro-optic deflector may exhibit a scanning speed of more than about  2 MHz. The system  100  may also include a scanner controller  122  coupled with the beam scanner  120 . The scanner controller  122  is adapted to regulate a scanning speed of the beam scanner  120 . 
     The scanned light pulses are directed over a pre-defined capture area of the physical structure  200 . In an exemplary embodiment, the pre-defined capture area may include the entire surface of the physical structure  200 . Upon striking the physical structure  200 , the directed scanned light beam may get backscattered (reflected back to the source direction) towards the system  100 . In an embodiment of the disclosure, a time clock counter may be initiated as soon as the scanned light beam is directed over the physical structure  200 . The time clock counter may enable a time of flight to be recorded for each of the light pulses as the light pulses travel to the physical structure  200  and get backscattered towards the light source  110 , upon striking the physical structure  200 . 
     The system  100  may include a photo-detector  130  for receiving the backscattered light pulses from the physical structure  200 . In an embodiment, the system  100  may also include an optics module  140  associated with the photo-detector  130 . The optics module  140  may include an arrangement of one or more lenses. The optics module  140  may enhance the collection of the backscattered light pulses from the physical structure  200 . In one embodiment, the system  100  may employ a receiving telescope (not illustrated) for receiving the backscattered light pulses from the physical structure  200 . 
     The photo-detector  130  upon receiving the backscattered light pulses may convert the backscattered light pulses into electric signals such as, but not limited to, a current signal. The photo-detector  130  is adapted to provide a current signal corresponding to each of the backscattered light pulses. In one embodiment, the photo-detector  130  is a fast response photo-detector, such as a Photomultiplier tube. Alternatively, the photo-detector  130  may be another type of photo-detector, such as one or more avalanche photodiodes. The photo-detector  130  may provide a combination of high gain, low noise, and high frequency response for the backscattered light pulses. The photo-detector  130  is capable of detecting backscattered light pluses separated by even less than lns and converts the backscattered light pulses into current signals. 
     The system  100  may further include a pre-processing module  150  coupled with the photo-detector  130 . The pre-processing module  150  may include a current amplifier, a signal converter, a digital converter, a peak detector and a threshold setting module. The pre-processing module  150  may receive the current signal corresponding to each of the light pulses generated by the photo-detector  130 . Subsequently, the current amplifier may amplify an amplitude of the current signal received from the photo-detector  130 . Further, the signal converter may convert the analog current signal to a corresponding analog voltage signal, which is further converted to a digitized voltage signal by the digital convertor. The peak detector may correspondingly identify a peak value of the digitized voltage signal. Since, there may a power degradation with the distance corresponding to various components of the physical structure  200 , from which the light pulses, upon striking, may get backscattered, neither peak detection of the signal nor a fixed threshold detection of the signal alone may provide a high enough resolution such as to a scale of about lmm. Thus, the threshold setting module normalizes the digitized voltage signal with the detected peak value and then adjusts a threshold on the detected peak value as the median value of the digitized voltage signal. The threshold setting module sets the threshold for each image individually. Such an adaptive threshold setting technique may enhance the accuracy of time of flight calculation for each backscattered light pulse. 
     Further, the time clock counter may provide a precise time of flight for each of the light pulses that, upon striking, are backscattered from the various points on the surface of the physical structure  200 . The precise time of flight may be calculated based at least in part on the consistent resolution that may be attained from the threshold adjustment. By counting the time between scanning of the light pulses, and returning of the backscattered light pulses, the distance between the light source and the various points on the surface of the physical structure  200  may be precisely calculated based on the constant speed of light in the air (299703 km/second). Also, the system  100  may include an association module  155  which is adapted to associate precisely calculated time of flight with each of the light pulse. 
     The distance between the light source and all the points on the surface of the physical structure  200  may be acquired continuously via scanning the light pulses with the scanner  120 . Thus, an image generator  160 , included in the system  100 , may continuously generate one or more three-dimensional images of the physical structure  200  having a consistent resolution based on the time of flight associated with each of the light pulses. The three-dimensional images include a plurality of pixels, each pixel having an intensity value of the backscattered light pulse, and the precise time of flight value associated with each pixel. 
     The system  100  may further include an image comparator  170  coupled with the image generator  160 . The image comparator  170  is adapted to compare the three-dimensional images, generated by the image generator  160 . Specifically, the image comparator  170  may compare the three-dimensional images generated by the image generator  160 , with a three-dimensional image of the physical structure  200  in an idle condition (healthy state). The image comparator  170  may have stored therein, the healthy state three-dimensional image of the physical structure  200 . Alternatively, the healthy state three-dimensional image may be a three-dimensional image previously formed by the image generator  160 . The image comparator  170  may compare the images based on the time of flight associated with each light pulse, based on which the images are generated by the image generator  160 . Since, the images are compared based on the precisely calculated time of flight, the image comparator  170  may be adapted to determine displacement to a scale of about at least one millimeter in the structural configuration of the physical structure  200 . 
     The system  100  may further include a health indicator module  180  coupled with the image comparator  170 . The health indicator module  180  generates a health profile of the physical structure  200  based on the deviation/displacement in the structural configuration of the physical structure  200 , determined by the image comparator  170 . The health profile may include information pertaining to specific portions of the physical structure  200 , upon which deviations in the structural configuration have occurred. Further, the health profile includes information regarding the extent of any deviations in the structural configuration of the specific portions of the physical structure  200 . For example, the health profile may provide real time information about the distributed stress, strain, and vibration conditions on the specific portions of the physical structure  200 . The health profile may further indicate (highlight) portions of the physical structure  200  having deviations in the structural configuration for which immediate inspection or maintenance is required. The health profile may be indicated by means of an alphanumeric display, a visual depiction of changes in the spectral signature, a flashing light or other such manners of indication. 
     In an embodiment of the disclosure, the image comparator  170  may compare the images of the physical structure in real time. For comparing the images in real time, the image comparator may receive multiple images simultaneously, which is achieved by utilizing the high speed scanner  120  having a scanning rate of more than about 100 Hz. Further, use of the short light pulses less than or equal to about lns and the use of high speed photo-detector  130 , which is capable of detecting backscattered light pluses separated by even less than 1 ns, may enable the image generator  160  to generate multiple images in a very short span of time. The above example of scanning rate and laser pulses may be specific to a particular kind of physical structure  200  such as wind turbine, however, it may be apparent to a person possessing ordinarily skill in the art that the scanning rate and the pulses duration may be changed as required with respect to the type of the physical structure  200 . 
       FIG. 2  illustrates an environment in which the system  100  is used in conjunction with the physical structure  200 , such as a wind turbine  300 . Specifically,  FIG. 2  illustrates the system  100  utilized for controlling the wind turbine  300 , according to an embodiment of the disclosure. The system  100  may be coupled with a control unit  400  (explained in detail in conjunction with  FIG. 3 ) to remotely control parameters of the wind turbine  300  for allowing the wind turbine  300  to operate efficiently. It is to be understood that the system  100 , shown in  FIG. 2  is functionally and configurationally similar to the system  100  shown in  FIG. 1 . 
     The system  100  may include the light source  110  adapted to generate short light pulses, constituting a light beam. In an exemplary embodiment, the light source  110  may be adapted to generate light pulses of less than or equal to about one nanosecond. The system  100  may be further adapted to scan the light beam and direct the scanned light beam towards the wind turbine  300 . In an exemplary embodiment, the system  100  may utilize a fast speed beam scanner  120 , having a scanning rate of approximately 2 MHz). The light pulses may get backscattered towards the system  100 , upon striking various points on a surface of the wind turbine  300 . The system  100  may receive the backscattered light pulses and may generate a current signal corresponding to each of the light pulses. Thereafter, the system  100  may amplify an amplitude of the current signal before converting the amplified current signal to an analog voltage signal. Further, the system  100  may digitize the analog voltage signal using any known analog to digital converters. 
     The system  100  may further process the digitized voltage signal to detect a peak value of the voltage signal to adjust a threshold of the voltage signal on the detected peak voltage signal. In one implementation, the system  100  may normalize the digitized voltage signal with the detected peak value and then adjust a threshold on the detected peak value as the median value of the digitized voltage signal. The threshold setting module sets the threshold for each image individually. Such an adaptive threshold setting technique may enhance the accuracy of time of flight calculation for each backscattered light pulse. 
     Further, as explained in  FIG. 1 , a time clock counter may provide a precise time of flight for each of the light pulses that, upon striking, are backscattered from the various points on the surface of the physical structure. The precise time of flight may be calculated based at least in part on the consistent resolution that may be attained from the threshold adjustment. Also, the system  100  may associate precisely calculated time of flight with each of the light pulse. 
     The distance between the light source and all the points on the surface of the physical structure may be acquired real time via scanning the light pulses through the high speed beam scanner  120 . Thus, the system  100 , may continuously generate one or more three-dimensional images of the wind turbine  300  having a consistent resolution based on the time of flight associated with each of the light pulses. The three-dimensional images include a plurality of pixels, each pixel having an intensity value of the backscattered light pulse, and the precise time of flight value associated with each pixel. 
     The system  100  may further compare the three-dimensional images of the wind turbine  300  with a three-dimensional image of the wind turbine  300  in an idle condition (healthy state). The system  100  may have stored therein, the healthy state three-dimensional image of the wind turbine  300 . Alternatively, the healthy state three-dimensional image may be a three-dimensional image previously generated by the system  100 . The system  100  may compare the images based on the time of flight associated with each light pulse, based on which the images are generated. Since, the images are compared based on the precisely calculated time of flight, the system  100  may be adapted to determine any displacement to a scale of about at least one millimeter in the structural configuration of the wind turbine  300 . The system  100  may subsequently generate a health profile for the wind turbine  300  based on the comparison of the three-dimensional images of the wind turbine  300 . 
     The health profile generated by the system  100  for the wind turbine  300  may include information regarding displacement/deviation in the structural configuration of any component or portion of the wind turbine  300 . Specifically, the health profile may provide real time information about the distributed stress, stain, and vibration condition on the component or portions of the wind turbine  300 . For example, the health profile may include information for a blade shape, blade displacement, blade bending and twisting, wind turbine tower top displacement, stress and strain analysis of one or more components of the wind turbine, vibration in one or more components of the wind turbine, and nacelle yaw angle. The health profile may be indicated by means of an alphanumeric display, a visual depiction of changes in the spectral signature, a flashing light or other such manners of indication. 
     As shown in  FIG. 2 , the control unit  400  may be communicably coupled with the system  100 . The control unit  400  may be adapted to change one or more parameters of the wind turbine  300  based at least in part on the health profile generated by the system  100 . The control unit  400  is explained in greater detail in conjunction with the  FIG. 3 . 
       FIG. 3  is a schematic diagram illustrating the system  100  along with the details of the control unit  400 . The control unit  400  may include an optimizing module  402  adapted to optimize the parameters of the wind turbine  300  for allowing the wind turbine  300  to operate efficiently. Specifically, the optimizing module  402  is adapted to determine the operational parameter values of various components of the wind turbine  300 . For example, the operational parameter values may include, but are not limited to pitch of blades, a yaw angle, speed of a shaft, and torque on the shaft. The optimizing module  402  is adapted to optimize the operational parameter values for various components of the wind turbine  300  based on the generated health profile of the wind turbine  300 . The generated health profile may include information regarding deviation in the structural configuration of the wind turbine  300 . It is to be understood that the deviation in the structural configuration may have occurred due to excess or prolong stress and/or strain on any component or portion of the wind turbine  300 . The optimizing module  402  may further consider an aerodynamic load of wind exposed to the wind turbine  300  while optimizing the operational parameter values. 
     The control unit  400  may also include a parameter control module  404  coupled with the optimizing module  402 . The parameter control module  404  may receive the optimized operational parameter values, determined by the optimizing module  402 , for controlling various components of the wind turbine  300 . In an exemplary embodiment, the parameter control module  404  may include various operational parameter controls, such as a pitch controller  412  adapted to control pitch angle of wind turbine blades, a yaw angle controller  414  adapted to control angle of a yaw, a speed controller  416  adapted to control speed of a wind turbine shaft, and a torque controller  418  adapted to control torque on the wind turbine shaft. However, the parameter control module  404  may include other operational parameter controls, such as temperature controller, gearbox gear mesh frequency amplitude controller and the like. 
     As shown in  FIG. 3 , the wind turbine  300  may be associated with a power output  502 . For example, the power output  502  may be 1000 kW. Further, to achieve the power output  502 , the wind turbine  300  may be fed with input parameter command  504 . The input parameter command  504  may include ideal operational parameter values, to be provided to the wind turbine  300  for achieving the power output  502 . For example, the input parameter command  504  may include ideal values, for the pitch angle of the wind turbine blades, the yaw angle, the speed for the wind turbine shaft, and the torque for the wind turbine shaft, which allows the wind turbine  300  to generate the power output  502 . It is to be understood that the input parameter command  504  may vary based on various aerodynamic loads to which the wind turbine  300  may be exposed. 
     In operation, the input parameter command  504  may provide the ideal operational parameter values to the control unit  400  to generate the power output  502 . The system  100  may simultaneously monitor the wind turbine  300 , and may generate a health profile for the wind turbine  300  based on the comparison of the three-dimensional images of the wind turbine  300 . In an instance, when the system  100  may identify any deviation/displacement in structural configuration for any component or portion of the wind turbine  300  (which may be on the order of about 1 mm), the system  100  may generate a health profile. The health profile may highlight such deviation/displacement in structural configuration of the concerned portion or component of the wind turbine  300 . 
     It is to be understood that the deviation in the structural configuration of any component or portion of the wind turbine  300  may occur when the wind turbine  300  may be subjected to an unexpected aerodynamic load of wind or unexpected weather condition. Alternatively, the deviation in the structural configuration of any component or portion may occur with time, when such component or portion may be subjected to continuous stress and/or strain. Due to such deviation in the structural configuration of the wind turbine  300 , the wind turbine  300  may not be able to generate the power output  502 . Accordingly, the operational parameter values of the wind turbine  300  need to be altered based on the health profile (deviation/displacement in the structural configuration of the wind turbine  300 ) generated by the system  100 . 
     The deviation in the structural configuration of the component or portion of the wind turbine  300  may be a temporary deviation, in which such component or portion may be adapted to regain an original shape thereof. For example, when the wind turbine  300  may be exposed to the unexpected aerodynamic load, the components or various portions of the wind turbine  300 , subjected to stress and/or strain, may undergo temporary deviation in terms of structural configuration. However, upon removal of the unexpected aerodynamic load, the components or various portions of the wind turbine  300  may regain the original shape thereof. 
     In case of temporary deviation in the structural configuration of the wind turbine  300 , the operational parameter values of the wind turbine  300  may be altered by the control unit  400  to allow the wind turbine  300  to operate efficiently. For example, the deviation in the structural configuration may cause change in the operational parameter values, such as change in the pitch angle, the yaw angle, and the speed and torque of the shaft. The optimizing module  402  of the control unit  400  may accordingly optimize the changed operational parameter values. Specifically, the optimizing module  402  may compare the changed operational parameter values with the ideal operational parameter values. Thereafter, the optimized operational parameter values may be received by the parameter control module  404  for controlling various operational parameter controls, such as the pitch controller  412 , the yaw angle controller  414 , the speed controller  416  and the torque controller  418 . This may allow the wind turbine  300  to operate efficiently for generating the power output  502 . 
     Further, the deviation in the structural configuration of the component or portion of the wind turbine  300  may be even more significant, which may lead to catastrophic wind turbine failure. For example, sudden heavy aerodynamic wind loads may cause blades to twist, flap at the blade tips, or bend in the plane of rotation. In such instances, the health profile generated by the system  100  may provide information regarding such deviation in the structural configuration of the wind turbine  300 . Accordingly, an overspeed protection mechanism, such as aerodynamically braking blades and friction brakes, may be applied to protect the wind turbine  300  from damage against such heavy aerodynamic wind loads. 
     Furthermore, the deviation in the structural configuration of the component or portion of the wind turbine  300  may be a permanent deviation. For example, excess or prolonged stress and/or strain on any component or portion of the wind turbine  300  may cause bending or cracking in such component or portion. In such an instance, the health profile generated by the system  100  provides information pertaining to such deviation in the structural configuration of the wind turbine  300 . Accordingly, the wind turbine  300  may be stopped in order to perform the necessary inspection and/or maintenance work on the component or portion of the wind turbine  300  so as to avoid failure thereof. 
     In yet another embodiment, the system  100  may be utilized for monitoring and controlling a plurality of wind turbines, such as the wind turbine  300 . Specifically, the system  100  may be employed on a wind farm having a plurality of wind turbines. In such an instance, the system  100  may be adapted to monitor and control the plurality of wind turbines based on the health profile, generated with the comparison of three-dimensional images of the wind turbines. It is to be understood that the system  100  may be associated with a driving mechanism, which may allow the system  100  to reach the plurality of wind turbines installed in the wind farm. 
     Further, the driving mechanism may be organized in a manner such that the system  100  may maintain an appropriate fixed distance with the wind turbines. One suitable example of the driving mechanism may include but is not limited to a wheel and rail arrangement. The driving mechanism may further include a driving means, which may allow the system  100  to automatically reach the wind turbines. Alternatively, the system  100  may be associated with a rotating mechanism for monitoring and controlling the plurality of wind turbines. The rotating mechanism may facilitate the system  100  in rotating about an axis thereof. It is to be understood that the system  100  may be positioned with respect to the wind turbines such that the system  100  may maintain an appropriate fixed distance with the wind turbines. 
     Referring now to  FIG. 4 , a flowchart of an example method  1000  for controlling the wind turbine  300  is shown, according to another embodiment. The method  1000  may control the wind turbine  300  based on the health profile generated with real time comparison of high resolution three-dimensional images of the wind turbine  300 . Based on the health profile, operational parameters of the wind turbine  300  may be altered for controlling the wind turbine  300 . 
     At  1002 , a scanned light beam may be sent towards a pre-defined capture area the wind turbine  300 . In an exemplary embodiment, the light beam may include short light pulses of less than or equal to about 1 ns. The light beam may be scanned by the beam scanner  120  coupled with the light source  110 . In an exemplary embodiment, the beam scanner  120  may exhibit a scanning speed of more than about 2 MHz. 
     In an exemplary embodiment, the pre-defined capture area may include the entire area of the wind turbine  300 . Upon striking the wind turbine  300 , the directed scanned light beam may get backscattered (reflected back to the direction it came from). 
     At  1004 , the photo-detector  130  may receive the backscattered light beam from the wind turbine  300 . In an exemplary embodiment, the optics module  140  is coupled with the photo-detector  130  and the optics module  140  may enhance a collection of the backscattered light pulses from the wind turbine  300 . 
     In an embodiment of the disclosure, the photo-detector  130 , upon receiving the backscattered light pulses, may convert the backscattered light pulse energy into electrical signals such as a current signal corresponding to each of the light pulses. The photo-detector  130  may provide a combination of high gain, low noise, and high frequency response for the backscattered light beam. The photo-detector  130  may be capable of detecting backscattered light pluses separated by even less than lns and still convert the backscattered light pulses energy into current signals. Further, the pre-processing module  150  may amplify an amplitude of the current signal. 
     At  1006 , the pre-processing module  150  may convert the current signal to an analog voltage signal and subsequently, employ an analog to digital converter to digitize the voltage signal corresponding to each of the received backscattered light pulses. 
     At  1008 , a peak value of the digitized voltage signal may be detected and subsequently, at  1010 , the threshold setting module may normalize the digitized voltage signal with the detected peak value and then adjust a threshold on the detected peak value as median value of the digitized voltage signal. The threshold setting module sets the threshold for each image individually. Such an adaptive threshold setting technique may enhance the accuracy of time of flight calculation for each backscattered light pulse. 
     At  1012 , the time clock counter may provide a precise time of flight for each of the light pulses that, upon striking, are backscattered from the various points on the surface of the wind turbine  300 . The precise time of flight may be calculated based at least in part on the consistent resolution that may be attained from the threshold adjustment. By counting the time between scanning of the light pulses, and returning of the backscattered light pulses, the distance between the light source and the various points on the surface of the wind turbine  300  may be precisely calculated based on the constant speed of light in the air (299703 km/second). Subsequently, at  1014 , the association module  155  may associate the precisely calculated time of flight with each of the light pulse. 
     The distance between the light source and all the points on the surface of the wind turbine  300  may be acquired continuously via scanning the light pulses with the scanner  120 . Thus, at  1016 , the image generator  160  may continuously generate one or more three-dimensional images of the wind turbine  300  having a consistent resolution based on the time of flight associated with each of the light pulses. 
     At  1018 , the image comparator  170  may compare the generated three-dimensional images of the wind turbine  300  with a three-dimensional image of the wind turbine  300  in an idle condition (healthy state). The image comparator  170  may compare the images based on the time of flight associated with each light pulse, based on which the images are generated by the image generator  160 . Since, the images are compared based on the precisely calculated time of flight, the image comparator  170  may be adapted to determine displacement to a scale of about at least one millimeter in the structural configuration of the wind turbine  300 . 
     At  1020 , the health indicator module  180  may generate a health profile of the wind turbine  300  based on the deviation/displacement in the structural configuration of the wind turbine  300 , determined by the image comparator  170 . The health profile may include information pertaining to specific portions, of the wind turbine  300 , on which deviation/displacement in the structural configuration have occurred. Further, the health profile includes information regarding the extent of deviation in the structural configuration of the specific portions of the wind turbine  300 . For example, the health profile may provide real time information about the distributed stress, stain, and vibration condition on the specific portions of the wind turbine  300 . 
     At  1022 , the control unit  400  may control one or more operational parameters values of the wind turbine  300  based on the generated health profile of the wind turbine  300 . For example, based on a deviation in the structural configuration of the wind turbine  300  may cause the control unit  400  to change in the operational parameter values, such as change in the pitch angle, the yaw angle, and the speed and torque of the shaft.