Converter Fault Diagnosis and Post-fault Operation of a Doubly-fed Induction Generator for a Wind Turbine PDF Download
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Author: Warachart Sae-Kok
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Wind energy has become one of the most important alternative energy resources because of the global warming crisis. Wind turbines are often erected off-shore because of favourable wind conditions, requiring lower towers than on-shore. The doubly-fed induction generator is one of the most widely used generators with wind turbines. In such a wind turbine the power converters are less robust than the generator and other mechanical parts. If any switch failure occurs in the converters, the wind turbine may be seriously damaged and have to stop. Therefore, converter health monitoring and fault diagnosis are important to improve system reliability. Moreover, to avoid shutting down the wind turbine, converter fault diagnosis may permit a change in control strategy and/or reconfigure the power converters to permit post-fault operation. This research focuses on switch fault diagnosis and post-fault operation for the converters of the doubly-fed induction generator. The effects of an open-switch fault and a short-circuit switch fault are analysed. Several existing open-switch fault diagnosis methods are examined but are found to be unsuitable for the doubly-fed induction generator. The causes of false alarms with these methods are investigated. A proposed diagnosis method, with false alarm suppression, has the fault detection capability equivalent to the best of the existing methods, but improves system reliability. After any open-switch fault is detected, reconfiguration to a four-switch topology is activated to avoid shutting down the system. Short-circuit switch faults are also investigated. Possible methods to deal with this fault are discussed and demonstrated in simulation. Operating the doubly-fed induction generator as a squirrel cage generator with aerodynamic power control of turbine blades is suggested if this fault occurs in the machine-side converter, while constant dc voltage control is suitable for a short-circuit switch fault in the grid-side converter.
Author: Warachart Sae-Kok
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Wind energy has become one of the most important alternative energy resources because of the global warming crisis. Wind turbines are often erected off-shore because of favourable wind conditions, requiring lower towers than on-shore. The doubly-fed induction generator is one of the most widely used generators with wind turbines. In such a wind turbine the power converters are less robust than the generator and other mechanical parts. If any switch failure occurs in the converters, the wind turbine may be seriously damaged and have to stop. Therefore, converter health monitoring and fault diagnosis are important to improve system reliability. Moreover, to avoid shutting down the wind turbine, converter fault diagnosis may permit a change in control strategy and/or reconfigure the power converters to permit post-fault operation. This research focuses on switch fault diagnosis and post-fault operation for the converters of the doubly-fed induction generator. The effects of an open-switch fault and a short-circuit switch fault are analysed. Several existing open-switch fault diagnosis methods are examined but are found to be unsuitable for the doubly-fed induction generator. The causes of false alarms with these methods are investigated. A proposed diagnosis method, with false alarm suppression, has the fault detection capability equivalent to the best of the existing methods, but improves system reliability. After any open-switch fault is detected, reconfiguration to a four-switch topology is activated to avoid shutting down the system. Short-circuit switch faults are also investigated. Possible methods to deal with this fault are discussed and demonstrated in simulation. Operating the doubly-fed induction generator as a squirrel cage generator with aerodynamic power control of turbine blades is suggested if this fault occurs in the machine-side converter, while constant dc voltage control is suitable for a short-circuit switch fault in the grid-side converter.
Author: Manoj Rathi
Publisher:
ISBN:
Category :
Languages : en
Pages : 250
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Book Description
Author: Monia Ben Khader Bouzid
Publisher: John Wiley & Sons
ISBN: 1394236433
Category : Technology & Engineering
Languages : en
Pages : 188
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Book Description
Wind energy conversion systems are subject to many different types of faults and therefore fault detection is highly important to ensure reliability and safety. Monitoring systems can help to detect faults before they result in downtime. This book presents efficient methods used to detect electrical and mechanical faults based on electrical signals occurring in the different components of a wind energy conversion system. For example, in a small and high power synchronous generator and multi-phase generator, in the diode bridge rectifier, the gearbox and the sensors. This book also presents a method for keeping the frequency and voltage of the power grid within an allowable range while ensuring the continuity of power supply in the event of a grid fault. Electrical and Mechanical Fault Diagnosis in Wind Energy Conversion Systems presents original results obtained from a variety of research. It will not only be useful as a guideline for the conception of more robust wind turbines systems, but also for engineers monitoring wind turbines and researchers
Author: Dhaval Shah
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Wind energy conversion is the fastest-growing source of renewable electric power generation in the world and it is expected to remain so for some time. Doubly Fed Induction Generators (DFIGs) hold more than 50% market share of wind power generators due to its unique benefits of low cost, control capability and scalability. Recent trend of DFIGs installed in wind power are within power range of 200KW-2MW and have stator windings rated at 690V, which are highly susceptible to inter-turn faults. This fault type account for more than 40% of the total failure causes of the generator. A reliable fault diagnostic system to detect this fault at incipient stage is highly in demand to prevent catastrophic failures and reduce preventive maintenance costs, since regular inspection is expensive and rewinding of generator takes time in period of days and costs nearly 20% of the original generator cost. Conventional techniques developed for detecting stator inter-turn faults in induction motor are not directly applicable for this machine partly due to difference in construction and their operating characteristics. Research for fault diagnosis in last 5 years has lead to variety of techniques, but none have proved to be feasible either due to need for dedicated sensors and high computing needs or they fail to account for operating conditions which lead to ambiguous fault triggering. This absence of any proven technique to detect stator inter-turn faults in DFIG and the dire necessity for a fault diagnostic system to promote their reliability in wind power generation has motivated the research of this thesis. A novel technique to detect stator inter-turn faults in a DFIG is proposed by analyzing rotor current and search coil voltage in this thesis. Our recent observations suggested that harmonics induced in the rotor circuit are very promising in detecting stator inter-turn faults in DFIGs. Hence. in this study, an in-depth investigation was conducted to determine the origin of various harmonic components in the rotor currents and their feasibility to detect inter-turn stator faults unambiguously. The theory is verified by modeling the DFIG and simulating various operating conditions of healthy state. severity of faults and unbalance loading conditions that cause ambiguity. Further to verify the concept, an experimental test-bed was created and tests were carried out on DFIG under varying speed operations, fault severity and loading conditions. The experimental results achieved from analyzing the frequency spectrum of rotor current and search coil voltage have been compared and discussed. To verify feasibility of the proposed technique for detecting stator inter-turn faults and obtain results on speed sensitivity of fault detection, a prototype of DSP based Fault Diagnostic device was developed. Further discussion is made on challenges of realizing the proposed fault diagnostic technique in the industry and scope for further improvement.
Author: Ahmed El-Naggar
Publisher:
ISBN:
Category : Technology
Languages : en
Pages :
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Book Description
The fault current contribution of the doubly fed induction generator-based wind turbines (DFIG-WTs) is dictated by a combination of factors, including the electrical parameters of the machine and the controller configuration of the converters. A detailed manufacturer-based simulation model for DFIG-WT was used for detailed analysis of the controller influences on short-circuit parameters. Based on the analysis, new approximate expressions of the short-circuit parameters were introduced and a new mathematical model of the short-circuit current were developed. The mathematical models and the expressions were later validated using nonlinear optimization for parameter extraction. Subsequently, a new method was introduced for fault current contribution calculation in a simple and reliable way similar to IEC-60909. The method is based on linearization and a newly introduced correction factor that takes the influence of the controller into account. Finally, the new introduced method was tested on a small wind farm and the results show better accuracy in comparison with IEC-60909.
Author: Fangzhou Cheng
Publisher:
ISBN: 9780355509748
Category : Induction generators
Languages : en
Pages : 0
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Book Description
In this dissertation, current-based fault diagnosis methods are proposed for wind turbine drivetrain gearboxes. New signal conditioning methods are developed to extract fault features from current signals of doubly-fed induction generator (DFIG)-based wind turbines under nonstationary conditions. A deep classifier consists of stacked autoencoder and support vector machine (SVM) is proposed to improve the accuracy of fault classification results of the traditional SVM classifier. Moreover, a new fault prognosis and RUL prediction method for drivetrain gearboxes based on adaptive neuro fuzzy inference system (ANFIS) and particle filtering (PF) technique is proposed. Finally, an enhanced PF algorithm is proposed to improve the fault prognosis and RUL prediction accuracy of the ANFIS-PF method. The proposed methods have been validated by small-scale permanent magnet synchronous generator (PMSG)- and DFIG-based wind turbine drivetrain simulators in the lab and MW-scale DFIG-based wind turbines in the field.
Author: S. Ganesh Kumar
Publisher: John Wiley & Sons
ISBN: 111979191X
Category : Science
Languages : en
Pages : 836
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Book Description
POWER CONVERTERS, DRIVES AND CONTROLS FOR SUSTAINABLE OPERATIONS Written and edited by a group of experts in the field, this groundbreaking reference work sets the standard for engineers, students, and professionals working with power converters, drives, and controls, offering the scientific community a way towards combating sustainable operations. The future of energy and power generation is complex. Demand is increasing, and the demand for cleaner energy and electric vehicles (EVs) is increasing with it. With this increase in demand comes an increase in the demand for power converters. Part one of this book is on switched-mode converters and deals with the need for power converters, their topologies, principles of operation, their steady-state performance, and applications. Conventional topologies like buck, boost, buck-boost converters, inverters, multilevel inverters, and derived topologies are covered in part one with their applications in fuel cells, photovoltaics (PVs), and EVs. Part two is concerned with electrical machines and converters used for EV applications. Standards for EV, charging infrastructure, and wireless charging methodologies are addressed. The last part deals with the dynamic model of the switched-mode converters. In any DC-DC converter, it is imperative to control the output voltage as desired. Such a control may be achieved in a variety of ways. While several types of control strategies are being evolved, the popular method of control is through the duty cycle of the switch at a constant switching frequency. This part of the book briefly reviews the conventional control theory and builds on the same to develop advanced techniques in the closed-loop control of switch mode power converters (SMPC), such as sliding mode control, passivity-based control, model predictive control (MPC), fuzzy logic control (FLC), and backstepping control. A standard reference work for veteran engineers, scientists, and technicians, this outstanding new volume is also a valuable introduction to new hires and students. Useful to academics, researchers, engineers, students, technicians, and other industry professionals, it is a must-have for any library.
Author: Vivek Meenakshi Sundaram
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
With the widespread use of doubly-fed induction generators (DFIG) in wind energy conversion systems, condition monitoring is being given importance. Non-intrusive techniques like motor current signature analysis (MCSA), which involves looking for specific frequency components in the current spectrum, are preferred over analysis of magnetic field, temperature, vibrations or acoustic noise which require additional sensors. The major difficulty in MCSA is isolation of the fault, as multiple faults produce similar signatures. Moreover, closed-loop control makes diagnostics more complicated due to inherent compensation by the controller. This thesis presents a method to diagnose static and dynamic air gap eccentricities in doubly-fed induction generators operated for closed-loop stator power control by using a modified control technique to enable detection and isolation of this fault from electrical unbalances in the stator and rotor and load torque oscillations that produce similar effects. The effectiveness of the proposed control is verified using simulations and preliminary experiments performed on a healthy machine.
Author: Graham Steven Pannell
Publisher:
ISBN:
Category :
Languages : en
Pages : 280
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Book Description
Author: Murali Mohan Baggu
Publisher:
ISBN:
Category : Electric current converters
Languages : en
Pages : 262
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Book Description
"A doubly-fed induction generator (DFIG) applied to wind power generation is under study for low voltage ride-through application during system disturbances. Conventional dq axis current control using voltage source converters for both the grid side and the rotor side of the DFIG are analyzed and simulated. DFIG operation is investigated under balanced and unbalanced system disturbances. A conventional d-axis and q-axis control applied to a voltage source converter (VSC) during a system imbalance exhibits oscillations in the stiff DC link voltage as well as in the real and reactive powers of the converter. Multiple advanced control methods are explored and compared for imbalance operations. An advanced control technique utilizing both positive and negative sequence domain is evaluated. The approach demonstrates the stabilization of the DC link voltage to a greater extent during a disturbance but is more sluggish than the conventional control. An innovative control strategy that employs the technique of direct power control (DPC) is also investigated. This control achieves real and reactive power stability with simple active and reactive power control variables replacing the current control loops in the conventional case. A modified DPC algorithm is proposed to eliminate the current harmonics created by DPC during system disturbances. The DPC is further extended to the rotor-side converter of the DFIG thus controlling the complete system using this technique. The DPC is implemented using a three-phase converter designed on a PCB using Eagle®. A Texas Instruments® TMS320F2812 DSP is used to implement the control algorithm. The converter is tested for ride through capability using an industrial power corruptor. The results are compared to the simulation results for compliance with standard grid codes"--Abstract, leaf iii.
