Feature extraction plays a key role in fault diagnosis of rotating machinery. Many methods report... more Feature extraction plays a key role in fault diagnosis of rotating machinery. Many methods reported in the literature are based on masses of labeled data and need much prior knowledge to select the most discriminating features or establish a complex deep-learning model. To solve the dilemma, a novel feature extraction method based on kernel principal component analysis (KPCA) and an autoencoder (AE), namely, SFS-KPCA-AE, is presented in this paper to automatically extract the most discriminative features from the frequency spectrum of vibration signals. First, fast Fourier transform is calculated on the entire vibration signal to get the frequency spectrum. Next, the spectrum is divided into several segments. Then, local-global feature extraction is performed by applying KPCA to these segments. Finally, an AE is employed to obtain the low-dimensional representations of the high-dimensional global feature. The proposed feature extraction method combined with a classifier achieves fau...
Proceedings of 1996 Canadian Conference on Electrical and Computer Engineering
Thermal models can be used to protect induction motors from excessive overheating resulting from ... more Thermal models can be used to protect induction motors from excessive overheating resulting from overloading, failure to start, unbalance and frequent starting. Such a model is adopted for use in a relaying algorithm. The developed algorithm accurately calculates the change in motor temperature and hence, protects the motor from excessive overheating. The lab results, included in this paper, of motor
2006 IEEE Power Engineering Society General Meeting, 2006
New problems emerging from the increased production of power from renewable resources are becomin... more New problems emerging from the increased production of power from renewable resources are becoming a good challenge. To face the new challenges, accurate modeling of such systems is required. For example, to be able to apply advanced control strategies, usually a linearized state space representation of the system is needed. Taking a variable speed cage machine wind generation system as
IEEE Transactions on Power Apparatus and Systems, 1973
Page 1. DIGITAL CONTROL SCHEME FORA GENERATING UNIT KJ Runtz, ASA Farag, DWHuber, GS Hope, 0. P. ... more Page 1. DIGITAL CONTROL SCHEME FORA GENERATING UNIT KJ Runtz, ASA Farag, DWHuber, GS Hope, 0. P. Malik ... This in turn has contributed to the appearance onthe market of themini-computer, the cost of which has been drastically reduc-ed over the past few years. ...
2009 IEEE/PES Power Systems Conference and Exposition, 2009
An experimental evaluation of a power differential relay is conducted and the results are describ... more An experimental evaluation of a power differential relay is conducted and the results are described. The experimental setup consists of a generator connected to the network via a transmission line protected by the power deferential relay. The relay input signals, fundamental active and reactive powers, are locally computed from the complex product of the current and voltage phasors at each
2013 26th IEEE Canadian Conference on Electrical and Computer Engineering (CCECE), 2013
ABSTRACT Characteristics of a small scale wind turbine using Permanent Magnet Synchronous Generat... more ABSTRACT Characteristics of a small scale wind turbine using Permanent Magnet Synchronous Generator and connected to a grid through a reduced switches count converter (two legs only) are studied in this paper. Active power output corresponding with the input is given with the reactive power produced by the wind turbine regulated at 0 MVAr. Variable wind speed is optimum for drive train performance at 10 m/s (at maximum power coefficient point). When wind speed changes, the turbine moves away from its optimal tip speed ratio until maximum power point tracking forces the turbine to operate at its optimal speed. The generator torque is regulated by controlling the generator current based on the principle of field oriented control where a decoupling between the field and torque current components is achieved. The generator reference voltage and the converter switching signals are synthesized using the principle of space vector modulation. A 5.7 kW grid-connected variable speed wind turbine is simulated using Matlab/Simulink to study the feasibility of the proposed control technique.
International Journal of Surface Mining, Reclamation and Environment, 1987
The paper presents a relatively new method of sizing the distribution electrical equipment used t... more The paper presents a relatively new method of sizing the distribution electrical equipment used to supply groups of excavators working in open-pit mines. In particular, the problem of sizing of impact-loaded transformers is discussed and an appropriate algorithm is given. The theoretical background of the method is outlined with reference to the earlier works of the authors. An illustrative example of the method application is given.
System identification plays an extremely important role in the self-tuning controller. As the rec... more System identification plays an extremely important role in the self-tuning controller. As the recursive least squares (RLS)identification technique has the advantages of simple calculation and good convergence properties, it is the preferred technique for use in the design of the self-tuning controllers. However, use of RLS identification in a real-time environment does raise some problems such as the speed of parameter convergence, identification going to ‘sleep’, covariance matrix ‘blow up’, biased identification, etc. This paper deals with the problems which may arise in the practical use of the RLS identification technique. These issues are the summary of several years' experience of designing self-tuning controllers with RLS identification technique for power system applications. Although some of these issues are difficult to analyse, they are quite effective in dealing with the practical problems.
Power systems are non-linear: the structure and parameters of a network are time varying and cann... more Power systems are non-linear: the structure and parameters of a network are time varying and cannot be represented accurately by a linear model under all operating conditions. In addition power system disturbances are random in nature, therefore self-tuning controllers are more suitable for power system control than constant parameter linear controllers. The non-minimum phase nature of power systems prohibits the use of simple minimum-variance self-tuning controllers. Generalized minimum variance control can be used to overcome this difficulty. Using multi-input multi-output (MIMO) control, the control efforts of both the excitation and governor systems can be coordinated to improve dynamic stability. The objective of this paper is to present the results obtained from simulation studies in which the MIMO generalized minimum variance control, with square-root least-squares identification and variable forgetting factor, is used to improve the damping of the power system oscillations.
The ability of a dual-rate adaptive stabilizer to damp multimode oscillations in a power system i... more The ability of a dual-rate adaptive stabilizer to damp multimode oscillations in a power system is investigated. The controller adjusts its parameters to track the dominant frequency of oscillation and damps different modes one by one according to their dominance. The results show that adaptive and conventional stabilizers working on different units within a system can operate cooperatively and mutually
A transmission line distance relaying technique using an on-line trained neural network (NN) is d... more A transmission line distance relaying technique using an on-line trained neural network (NN) is developed. Results of numerical simulation and experimental studies show very good accuracy and fast estimation of distance to fault for various faults under different operating conditions, high fault resistance, and remote-end feed.
The use of an adaptive optimal control algorithm for two real-time control applications, an optim... more The use of an adaptive optimal control algorithm for two real-time control applications, an optimal excitation control of a synchronous generator (OEC) and a power system stabilizer (PSS), is described. Experimental studies on a physical model of a power system showed that the proposed OEC and PSS can track the controlled system by parameter identification at different operating conditions. The proposed algorithm is based on linear optimal control theory. A special fifth-order discrete Riccati equation is solved in each sampling period. The proposed OEC and PSS can always guarantee that in a closed loop the controlled system will be stable based on the identified parameters. As the actual output of the controlled system and control are directly used in the controller, no observer is required. The proposed OEC and PSS can track the controlled system very rapidly. A number of tests have been performed, and all show satisfactory results
... Principal Branches' of the plot for eqn.(l). Before going into specific examples, it mus... more ... Principal Branches' of the plot for eqn.(l). Before going into specific examples, it must be emphasised, that the model formulation for a system by this technique is somewhat dependent on the particular plant. As is evident from the above discussion, the effect of dead-time on the ...
A digital frequency measurement approach and its implementation for use in conjunction with a dup... more A digital frequency measurement approach and its implementation for use in conjunction with a duplex fault-tolerant microprocessor-based governor for water turbines is described. The proposed approach has a wide measuring range, high resolution, and fast response. The circuitry and the software are simple. The interface to the generating plant is direct and simple. Due to the direct measurement of the frequency instead of speed, it can adapt to any plant without changes to either the hardware or the software. Results in an actual power system environment have proven that the proposed measurement technique can meet the requirements of speed control in electric power systems
Feature extraction plays a key role in fault diagnosis of rotating machinery. Many methods report... more Feature extraction plays a key role in fault diagnosis of rotating machinery. Many methods reported in the literature are based on masses of labeled data and need much prior knowledge to select the most discriminating features or establish a complex deep-learning model. To solve the dilemma, a novel feature extraction method based on kernel principal component analysis (KPCA) and an autoencoder (AE), namely, SFS-KPCA-AE, is presented in this paper to automatically extract the most discriminative features from the frequency spectrum of vibration signals. First, fast Fourier transform is calculated on the entire vibration signal to get the frequency spectrum. Next, the spectrum is divided into several segments. Then, local-global feature extraction is performed by applying KPCA to these segments. Finally, an AE is employed to obtain the low-dimensional representations of the high-dimensional global feature. The proposed feature extraction method combined with a classifier achieves fau...
Proceedings of 1996 Canadian Conference on Electrical and Computer Engineering
Thermal models can be used to protect induction motors from excessive overheating resulting from ... more Thermal models can be used to protect induction motors from excessive overheating resulting from overloading, failure to start, unbalance and frequent starting. Such a model is adopted for use in a relaying algorithm. The developed algorithm accurately calculates the change in motor temperature and hence, protects the motor from excessive overheating. The lab results, included in this paper, of motor
2006 IEEE Power Engineering Society General Meeting, 2006
New problems emerging from the increased production of power from renewable resources are becomin... more New problems emerging from the increased production of power from renewable resources are becoming a good challenge. To face the new challenges, accurate modeling of such systems is required. For example, to be able to apply advanced control strategies, usually a linearized state space representation of the system is needed. Taking a variable speed cage machine wind generation system as
IEEE Transactions on Power Apparatus and Systems, 1973
Page 1. DIGITAL CONTROL SCHEME FORA GENERATING UNIT KJ Runtz, ASA Farag, DWHuber, GS Hope, 0. P. ... more Page 1. DIGITAL CONTROL SCHEME FORA GENERATING UNIT KJ Runtz, ASA Farag, DWHuber, GS Hope, 0. P. Malik ... This in turn has contributed to the appearance onthe market of themini-computer, the cost of which has been drastically reduc-ed over the past few years. ...
2009 IEEE/PES Power Systems Conference and Exposition, 2009
An experimental evaluation of a power differential relay is conducted and the results are describ... more An experimental evaluation of a power differential relay is conducted and the results are described. The experimental setup consists of a generator connected to the network via a transmission line protected by the power deferential relay. The relay input signals, fundamental active and reactive powers, are locally computed from the complex product of the current and voltage phasors at each
2013 26th IEEE Canadian Conference on Electrical and Computer Engineering (CCECE), 2013
ABSTRACT Characteristics of a small scale wind turbine using Permanent Magnet Synchronous Generat... more ABSTRACT Characteristics of a small scale wind turbine using Permanent Magnet Synchronous Generator and connected to a grid through a reduced switches count converter (two legs only) are studied in this paper. Active power output corresponding with the input is given with the reactive power produced by the wind turbine regulated at 0 MVAr. Variable wind speed is optimum for drive train performance at 10 m/s (at maximum power coefficient point). When wind speed changes, the turbine moves away from its optimal tip speed ratio until maximum power point tracking forces the turbine to operate at its optimal speed. The generator torque is regulated by controlling the generator current based on the principle of field oriented control where a decoupling between the field and torque current components is achieved. The generator reference voltage and the converter switching signals are synthesized using the principle of space vector modulation. A 5.7 kW grid-connected variable speed wind turbine is simulated using Matlab/Simulink to study the feasibility of the proposed control technique.
International Journal of Surface Mining, Reclamation and Environment, 1987
The paper presents a relatively new method of sizing the distribution electrical equipment used t... more The paper presents a relatively new method of sizing the distribution electrical equipment used to supply groups of excavators working in open-pit mines. In particular, the problem of sizing of impact-loaded transformers is discussed and an appropriate algorithm is given. The theoretical background of the method is outlined with reference to the earlier works of the authors. An illustrative example of the method application is given.
System identification plays an extremely important role in the self-tuning controller. As the rec... more System identification plays an extremely important role in the self-tuning controller. As the recursive least squares (RLS)identification technique has the advantages of simple calculation and good convergence properties, it is the preferred technique for use in the design of the self-tuning controllers. However, use of RLS identification in a real-time environment does raise some problems such as the speed of parameter convergence, identification going to ‘sleep’, covariance matrix ‘blow up’, biased identification, etc. This paper deals with the problems which may arise in the practical use of the RLS identification technique. These issues are the summary of several years' experience of designing self-tuning controllers with RLS identification technique for power system applications. Although some of these issues are difficult to analyse, they are quite effective in dealing with the practical problems.
Power systems are non-linear: the structure and parameters of a network are time varying and cann... more Power systems are non-linear: the structure and parameters of a network are time varying and cannot be represented accurately by a linear model under all operating conditions. In addition power system disturbances are random in nature, therefore self-tuning controllers are more suitable for power system control than constant parameter linear controllers. The non-minimum phase nature of power systems prohibits the use of simple minimum-variance self-tuning controllers. Generalized minimum variance control can be used to overcome this difficulty. Using multi-input multi-output (MIMO) control, the control efforts of both the excitation and governor systems can be coordinated to improve dynamic stability. The objective of this paper is to present the results obtained from simulation studies in which the MIMO generalized minimum variance control, with square-root least-squares identification and variable forgetting factor, is used to improve the damping of the power system oscillations.
The ability of a dual-rate adaptive stabilizer to damp multimode oscillations in a power system i... more The ability of a dual-rate adaptive stabilizer to damp multimode oscillations in a power system is investigated. The controller adjusts its parameters to track the dominant frequency of oscillation and damps different modes one by one according to their dominance. The results show that adaptive and conventional stabilizers working on different units within a system can operate cooperatively and mutually
A transmission line distance relaying technique using an on-line trained neural network (NN) is d... more A transmission line distance relaying technique using an on-line trained neural network (NN) is developed. Results of numerical simulation and experimental studies show very good accuracy and fast estimation of distance to fault for various faults under different operating conditions, high fault resistance, and remote-end feed.
The use of an adaptive optimal control algorithm for two real-time control applications, an optim... more The use of an adaptive optimal control algorithm for two real-time control applications, an optimal excitation control of a synchronous generator (OEC) and a power system stabilizer (PSS), is described. Experimental studies on a physical model of a power system showed that the proposed OEC and PSS can track the controlled system by parameter identification at different operating conditions. The proposed algorithm is based on linear optimal control theory. A special fifth-order discrete Riccati equation is solved in each sampling period. The proposed OEC and PSS can always guarantee that in a closed loop the controlled system will be stable based on the identified parameters. As the actual output of the controlled system and control are directly used in the controller, no observer is required. The proposed OEC and PSS can track the controlled system very rapidly. A number of tests have been performed, and all show satisfactory results
... Principal Branches' of the plot for eqn.(l). Before going into specific examples, it mus... more ... Principal Branches' of the plot for eqn.(l). Before going into specific examples, it must be emphasised, that the model formulation for a system by this technique is somewhat dependent on the particular plant. As is evident from the above discussion, the effect of dead-time on the ...
A digital frequency measurement approach and its implementation for use in conjunction with a dup... more A digital frequency measurement approach and its implementation for use in conjunction with a duplex fault-tolerant microprocessor-based governor for water turbines is described. The proposed approach has a wide measuring range, high resolution, and fast response. The circuitry and the software are simple. The interface to the generating plant is direct and simple. Due to the direct measurement of the frequency instead of speed, it can adapt to any plant without changes to either the hardware or the software. Results in an actual power system environment have proven that the proposed measurement technique can meet the requirements of speed control in electric power systems
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