10th ECCOMAS Thematic Conference on Smart Structures and Materials
Global power capacity is increasingly being comprised by renewable energy sources, where wind far... more Global power capacity is increasingly being comprised by renewable energy sources, where wind farms stand out as paramount power stations. Therefore, the structural health of wind turbines (WTs) represents an essential factor in the energy industry. Specifically, offshore jacket-type WT supports are under critical operational and environmental conditions. Hence, a damage detection strategy is stated, considering several types of structural states and limitations in the quantity of acquired data. The proposed methodology consists of a PCA-based data transformation, in which initially known healthy data are used to be compared with a set of data to be diagnosed; then the damage or healthy states are predicted based on the Mahalanobis distance and threshold value. Because it is a semi-supervised technique, there is no requirement to have damage data on hand to construct the model. The strategy is tested in a scaled-down WT experimental tower.
This work is concerned with active vibration mitigation in wind turbines (WT) but not through the... more This work is concerned with active vibration mitigation in wind turbines (WT) but not through the use of specifically tailored devices. Instead, a general control scheme is designed for torque and pitch controllers based on a super-twisting algorithm, which uses additional feedback of the fore-aft and side-to-side acceleration signals at the top of the WT tower to mitigate the vibrational behavior. In general, proposed methods to improve damping through pitch and torque control suffer from increased blade pitch actuator usage. However, in this work the blade pitch angle is smoothed leading to a decrease of the pitch actuator effort, among other benefits evidenced through numerical experiments. The most frequent faults induce vibrations in the corresponding WT subsystems. In fact, vibration monitoring has been recently used for fault diagnosis Thus, by means of vibration mitigation, different faulty conditions can be alleviated leading to a passive fault tolerant control. In this work, coupled non-linear aero-hydroservo-elastic simulations of a floating offshore wind turbine are carried out for one of the most common pitch actuator faults.
The active and reactive powers, P and Q, are crucial variables in the parallel operation of singl... more The active and reactive powers, P and Q, are crucial variables in the parallel operation of single-phase inverters using the droop method, introducing proportional droops in the inverter output frequency and voltage amplitude references. P and Q, or P-Q, are calculated as the product of the inverter output voltage and its orthogonal version with the output current, respectively. However, when sharing nonlinear loads these powers, Pav and Qav, should be averaged by low-pass filters (LPFs) with a very low cut-off frequency to avoid the high distortion induced by these loads. This forces the droop method to operate at a very low dynamic velocity and degrades the system stability. Then, different solutions have been proposed in literature to increase the system velocity, but only considering linear loads. Therefore, this work presents a method to calculate Pav and Qav using second-order generalized integrators (SOGI) to face this problem with nonlinear loads. A double SOGI (DSOGI) approach is applied to filter the nonlinear load current and provide its fundamental component to the inverter, leading to a faster dynamic velocity of the droop-based load sharing capability and improving the stability. The proposed method is shown to be faster than others in the literature when considering nonlinear loads, while smoothly driving the system with low distortion levels. Simulations, hardware-in-loop (HIL) and experimental results are provided to validate this proposal.
The future of wind energy industry passes through the use of larger and more flexible wind turbin... more The future of wind energy industry passes through the use of larger and more flexible wind turbines in remote locations, which are increasingly offshore to benefit stronger and more uniform wind conditions. Cost of operation and maintenance of offshore wind turbines is among 15-35% of the total cost. From this, 80% comes from unplanned maintenance due to different faults in the wind turbine components. Thus, an auspicious way to contribute to the increasing demands and challenges is by applying low-cost advanced fault detection schemes. This work proposes a new method for fault detection of wind turbine actuators and sensors faults in variable-speed wind turbines. For this purpose, time domain signals acquired from the operating wind turbine are converted into two-dimensional matrices to obtain gray-scale digital images. Then, the image pattern recognition is processed getting texture features under a multichannel representation. In this work, four types of texture features are used...
This work is concerned with active vibration mitigation in wind turbines (WT) but not through the... more This work is concerned with active vibration mitigation in wind turbines (WT) but not through the use of specifically tailored devices. Instead, a general control scheme is designed for torque and pitch controllers based on a super-twisting algorithm, which uses additional feedback of the fore-aft and side-to-side acceleration signals at the top of the WT tower to mitigate the vibrational behavior. In general, proposed methods to improve damping through pitch and torque control suffer from increased blade pitch actuator usage. However, in this work the blade pitch angle is smoothed leading to a decrease of the pitch actuator effort, among other benefits evidenced through numerical experiments. The most frequent faults induce vibrations in the corresponding WT subsystems. In fact, vibration monitoring has been recently used for fault diagnosis Thus, by means of vibration mitigation, different faulty conditions can be alleviated leading to a passive fault tolerant control. In this wor...
Descripció: A robust controller with chattering is proposed for variable speed control of a two-b... more Descripció: A robust controller with chattering is proposed for variable speed control of a two-bladed horizontal axis wind turbine similar to the DOE MOD-0 model. The chattering term provides robustness against un-modeled non-linearities. To validate the performance of ...
Renewable energy is a clean and inexhaustible source of energy, so every year interest in the stu... more Renewable energy is a clean and inexhaustible source of energy, so every year interest in the study and the search for improvements in production increases. Wind energy is one of the most used sources of energy, and therefore the need for predictive maintenance management to guarantee the reliability and operability of each of the wind turbines has become a great study opportunity. In this work, a fault detection system is developed by applying an anomaly detector based on principal component analysis (PCA), in order to state early warnings of possible faults in the main bearing. For the development of the model, SCADA data from a wind park in operation are utilized. The results obtained allow detection of failures even months before the fatal breakdown occurs. This model requires (to be constructed) only the use of healthy SCADA data, without the need to obtain the fault history or install additional equipment or sensors that require greater investment. In conclusion, this proposed strategy provides a tool for the planning and execution of predictive maintenance within wind parks.
Nowadays, wind turbine fault detection strategies are settled as a meaningful pipeline to achieve... more Nowadays, wind turbine fault detection strategies are settled as a meaningful pipeline to achieve required levels of efficiency, availability, and reliability, considering there is an increasing installation of this kind of machinery, both in onshore and offshore configuration. In this work, it has been applied a strategy that makes use of SCADA data with an increased sampling rate. The employed wind turbine in this study is based on an advanced benchmark, established by the National Renewable Energy Laboratory (NREL) of USA. Different types of faults on several actuators and sensed by certain installed sensors have been studied. The proposed strategy is based on a normality model by means of an autoencoder. As of this, faulty data are used for testing from which prediction errors were computed to detect if those raise a fault alert according to a defined metric which establishes a threshold on which a wind turbine works securely. The obtained results determine that the proposed str...
10th ECCOMAS Thematic Conference on Smart Structures and Materials
Global power capacity is increasingly being comprised by renewable energy sources, where wind far... more Global power capacity is increasingly being comprised by renewable energy sources, where wind farms stand out as paramount power stations. Therefore, the structural health of wind turbines (WTs) represents an essential factor in the energy industry. Specifically, offshore jacket-type WT supports are under critical operational and environmental conditions. Hence, a damage detection strategy is stated, considering several types of structural states and limitations in the quantity of acquired data. The proposed methodology consists of a PCA-based data transformation, in which initially known healthy data are used to be compared with a set of data to be diagnosed; then the damage or healthy states are predicted based on the Mahalanobis distance and threshold value. Because it is a semi-supervised technique, there is no requirement to have damage data on hand to construct the model. The strategy is tested in a scaled-down WT experimental tower.
This work is concerned with active vibration mitigation in wind turbines (WT) but not through the... more This work is concerned with active vibration mitigation in wind turbines (WT) but not through the use of specifically tailored devices. Instead, a general control scheme is designed for torque and pitch controllers based on a super-twisting algorithm, which uses additional feedback of the fore-aft and side-to-side acceleration signals at the top of the WT tower to mitigate the vibrational behavior. In general, proposed methods to improve damping through pitch and torque control suffer from increased blade pitch actuator usage. However, in this work the blade pitch angle is smoothed leading to a decrease of the pitch actuator effort, among other benefits evidenced through numerical experiments. The most frequent faults induce vibrations in the corresponding WT subsystems. In fact, vibration monitoring has been recently used for fault diagnosis Thus, by means of vibration mitigation, different faulty conditions can be alleviated leading to a passive fault tolerant control. In this work, coupled non-linear aero-hydroservo-elastic simulations of a floating offshore wind turbine are carried out for one of the most common pitch actuator faults.
The active and reactive powers, P and Q, are crucial variables in the parallel operation of singl... more The active and reactive powers, P and Q, are crucial variables in the parallel operation of single-phase inverters using the droop method, introducing proportional droops in the inverter output frequency and voltage amplitude references. P and Q, or P-Q, are calculated as the product of the inverter output voltage and its orthogonal version with the output current, respectively. However, when sharing nonlinear loads these powers, Pav and Qav, should be averaged by low-pass filters (LPFs) with a very low cut-off frequency to avoid the high distortion induced by these loads. This forces the droop method to operate at a very low dynamic velocity and degrades the system stability. Then, different solutions have been proposed in literature to increase the system velocity, but only considering linear loads. Therefore, this work presents a method to calculate Pav and Qav using second-order generalized integrators (SOGI) to face this problem with nonlinear loads. A double SOGI (DSOGI) approach is applied to filter the nonlinear load current and provide its fundamental component to the inverter, leading to a faster dynamic velocity of the droop-based load sharing capability and improving the stability. The proposed method is shown to be faster than others in the literature when considering nonlinear loads, while smoothly driving the system with low distortion levels. Simulations, hardware-in-loop (HIL) and experimental results are provided to validate this proposal.
The future of wind energy industry passes through the use of larger and more flexible wind turbin... more The future of wind energy industry passes through the use of larger and more flexible wind turbines in remote locations, which are increasingly offshore to benefit stronger and more uniform wind conditions. Cost of operation and maintenance of offshore wind turbines is among 15-35% of the total cost. From this, 80% comes from unplanned maintenance due to different faults in the wind turbine components. Thus, an auspicious way to contribute to the increasing demands and challenges is by applying low-cost advanced fault detection schemes. This work proposes a new method for fault detection of wind turbine actuators and sensors faults in variable-speed wind turbines. For this purpose, time domain signals acquired from the operating wind turbine are converted into two-dimensional matrices to obtain gray-scale digital images. Then, the image pattern recognition is processed getting texture features under a multichannel representation. In this work, four types of texture features are used...
This work is concerned with active vibration mitigation in wind turbines (WT) but not through the... more This work is concerned with active vibration mitigation in wind turbines (WT) but not through the use of specifically tailored devices. Instead, a general control scheme is designed for torque and pitch controllers based on a super-twisting algorithm, which uses additional feedback of the fore-aft and side-to-side acceleration signals at the top of the WT tower to mitigate the vibrational behavior. In general, proposed methods to improve damping through pitch and torque control suffer from increased blade pitch actuator usage. However, in this work the blade pitch angle is smoothed leading to a decrease of the pitch actuator effort, among other benefits evidenced through numerical experiments. The most frequent faults induce vibrations in the corresponding WT subsystems. In fact, vibration monitoring has been recently used for fault diagnosis Thus, by means of vibration mitigation, different faulty conditions can be alleviated leading to a passive fault tolerant control. In this wor...
Descripció: A robust controller with chattering is proposed for variable speed control of a two-b... more Descripció: A robust controller with chattering is proposed for variable speed control of a two-bladed horizontal axis wind turbine similar to the DOE MOD-0 model. The chattering term provides robustness against un-modeled non-linearities. To validate the performance of ...
Renewable energy is a clean and inexhaustible source of energy, so every year interest in the stu... more Renewable energy is a clean and inexhaustible source of energy, so every year interest in the study and the search for improvements in production increases. Wind energy is one of the most used sources of energy, and therefore the need for predictive maintenance management to guarantee the reliability and operability of each of the wind turbines has become a great study opportunity. In this work, a fault detection system is developed by applying an anomaly detector based on principal component analysis (PCA), in order to state early warnings of possible faults in the main bearing. For the development of the model, SCADA data from a wind park in operation are utilized. The results obtained allow detection of failures even months before the fatal breakdown occurs. This model requires (to be constructed) only the use of healthy SCADA data, without the need to obtain the fault history or install additional equipment or sensors that require greater investment. In conclusion, this proposed strategy provides a tool for the planning and execution of predictive maintenance within wind parks.
Nowadays, wind turbine fault detection strategies are settled as a meaningful pipeline to achieve... more Nowadays, wind turbine fault detection strategies are settled as a meaningful pipeline to achieve required levels of efficiency, availability, and reliability, considering there is an increasing installation of this kind of machinery, both in onshore and offshore configuration. In this work, it has been applied a strategy that makes use of SCADA data with an increased sampling rate. The employed wind turbine in this study is based on an advanced benchmark, established by the National Renewable Energy Laboratory (NREL) of USA. Different types of faults on several actuators and sensed by certain installed sensors have been studied. The proposed strategy is based on a normality model by means of an autoencoder. As of this, faulty data are used for testing from which prediction errors were computed to detect if those raise a fault alert according to a defined metric which establishes a threshold on which a wind turbine works securely. The obtained results determine that the proposed str...
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