Udaya Annakkage - Academia.edu (original) (raw)
Papers by Udaya Annakkage
Profound changes are affecting the economics of the power systems sector such as the emergence of... more Profound changes are affecting the economics of the power systems sector such as the emergence of renewable energy sources and the introduction of energy markets, and these changes impact the knowledge and skill base required of power systems professionals. One area of focus in dealing with these changes is to examine undergraduate power systems engineering curricula, with a view to ensure relevance of content, adjust teaching and learning methods appropriately, and attract and retain students. This is particularly important as the workforce in the field is rapidly approaching the age of retirement, and replenishing this workforce with appropriately equipped engineering graduates is critical for the maintenance of a secure and smoothly operating electrical system. This paper sets the stage for an evaluation of the undergraduate power system curriculum, by outlining the background of evaluation research and describing the evaluation plan proposed for the undergraduate power systems p...
IEEE Open Access Journal of Power and Energy
Leading to the enormous growth in renewable and power electronics technologies and the global dri... more Leading to the enormous growth in renewable and power electronics technologies and the global drive towards environmental friendliness and sustainability, a significant number of renewable energy sources are being connected to the power system via inverter-based systems. The inverter-based generations (IBG) have no stored energy and less fault current injection capability compared to the conventional synchronous machines. Consequently, a large penetration of IBG creates challenges to maintaining the stability of the power system, especially the transient stability. The weaker the power system, the higher the significance of instability. Few solutions exist in the literature to improve the fault recovery of IBG connected to weak power systems. This paper considers the method of storing energy in sub-module capacitors of the Modular-Multi-level Converter (MMC) along with temporarily boosting the inverter's current limit. Conversely, increasing the ratings of the inverter will result in high manufacturing costs. Hence an optimization strategy is proposed in this paper, for obtaining a robust set of inverter control parameters that enhances fault recovery without excessively increasing the manufacturing cost of MMC. A frequency scanning technique supplemented with Generalized Nyquist criteria is incorporated into the optimization methodology to constrain the search space for the optimization algorithm. This enables the optimization algorithm to converge to an acceptable solution with a reasonable computing time. Furthermore, validation of the resultant set of parameters for different system conditions is presented. Finally, IBG with optimized fault recovery controllers is integrated into a simplified real-world power system, and the applicability of the proposed optimized controllers is illustrated.
IEEE Access
This paper proposes a novel three-stage near real-time phase-driven procedure to locate the gener... more This paper proposes a novel three-stage near real-time phase-driven procedure to locate the generator-type source of forced oscillations, inspired by the concept of Transient Energy Function (TEF), independent of the amplitude of any signal. In the commencement of the process, each generation bus is assigned with its active power and angular velocity angles reached from the reduced power system graph. Next, the difference in the synchronous generators' active power angles and the difference in their angular velocity angles is exploited as the graph branches' weight coefficients. Then, three exclusive and first-proposed decision functions are applied sequentially. First, the weighting coefficients of branches and nodes are fed to the first decision function. Regardless of the grid size, the result of this step is limited to up to four generators. The next step focuses exclusively on the first step outcomes, which results in two generators as recommended items. The last step, relying on the output of the second one, reveals the target generator accurately. The methodological procedure has been validated on the New England 10-machine 39-bus benchmark power system modelled in the Real-Time Digital Simulator (RTDS/RSCAD) and then scrutinised in the MATLAB environment. In each study scenario, the results are compared with the conventional transient energy method. The simulation results revealed that the presented approach reliably releases all sources, including limit cycle and turbine governing reference signal modulation, under the most intense parametric resonance.
2018 IEEE Electrical Power and Energy Conference (EPEC), 2018
This paper presents a linearized state-space model of the hybrid cascaded modular multilevel volt... more This paper presents a linearized state-space model of the hybrid cascaded modular multilevel voltage source converter. The developed model is validated against a detailed non-linear Electromagnetic Transient (EMT) simulation model. The impact of the ac system strength on the performance of the converter is investigated for moderately strong and weak systems. An eigenvalue analysis is conducted for both scenarios, with focus on the oscillatory modes present in the system in order to evaluate the stability constraints of the converter when connected to ac networks of different strengths.
IEEE Access, 2020
This paper utilizes modern statistical and machine learning methodology to predict the oscillatio... more This paper utilizes modern statistical and machine learning methodology to predict the oscillation mode of interest in complex power engineering systems. The damping ratio of the electromechanical oscillation mode is formulated as a function of the power of the generators and loads as well as bus voltage magnitudes in the entire power system. The celebrated Lasso algorithm is implemented to solve this highdimension modeling problem. By the nature of the L 1 design, the Lasso algorithm can automatically render a sparse solution, and by eliminating redundant features, it provides desirable prediction power. The resultant model processes a simple structure, and it is easily interpretable. The precision of our sparse modeling framework is demonstrated in the context of an IEEE 50-Generator 145-Bus power network and an online learning framework for the power system oscillation mode prediction is also provided.
Proceedings of International Conference on Intelligent System Application to Power Systems
This paper demonstrates how the simulated annealing algorithm and genetic algorithms can be used ... more This paper demonstrates how the simulated annealing algorithm and genetic algorithms can be used as means to solve the power system unit commitment problem. In addition, this paper presents parallel approaches to speed up the computational requirement of the simulated annealing algorithm. The algorithms were tested with two different problems. The results have demonstrated the success of the algorithms in consistently reaching good solutions.
Optimum power system stabilizer design has been a difficult task due to the nonlinear dynamics of... more Optimum power system stabilizer design has been a difficult task due to the nonlinear dynamics of the synchronous generators. An optimum power system stabilizer which is compensated for the nonlinear operation of the machine is described. A simple linear model of the synchronous machine is obtained at a given operating point by linearizing the nonlinear machine equations. The nonlinear characteristics of the machine are compensated by changing the linear model parameters depending on the prevailing operating condition of the machine. Optimum state feedback gains of the controller are calculated for the different sets of model parameters and scheduled according to the operating state. The algorithm presented can be considered as a generalization of the gain scheduling adaptive algorithms. Machine dynamics for different operating conditions are simulated to evaluate the effectiveness of this algorithm. The results show that the dynamic stability of the system is improved.
POWERCON '98. 1998 International Conference on Power System Technology. Proceedings (Cat. No.98EX151)
This paper presents a strategy for undervoltage load shedding in power systems. An undervoltage l... more This paper presents a strategy for undervoltage load shedding in power systems. An undervoltage load shedding (UVLS) criterion is defined using a generic dynamic load model to determine the amount of load to shed at a given voltage. The 'when and where' for load shedding is determined by identifying the weakest node in the network using a voltage collapse proximity indicator (VCPI). The magnitude of the VCPI is determined by estimating the ratio of the impedance of the load to the Thevenin impedance looking into the network at a given voltage. If required, further load shedding can be carried out by observing the VCPI. The strategy is simple, reliable and can be applied to any power system.
IEE Proceedings - Generation, Transmission and Distribution, 1998
The paper presents a technique for undervoltage load shedding (UVLS) in power systems. The underv... more The paper presents a technique for undervoltage load shedding (UVLS) in power systems. The undervoltage load shedding criterion has been developed using a dynamic load model. The parameters of the dynamic load model are estimated online using a nonlinear least squares technique, namely the Gauss-Newton method. The amount of load to be shed is calculated using the parameters of the dynamic load model. In the event of a voltage unstable situation, the proposed undervoltage load shedding criterion can be used to calculate the minimum amount of load to be shed at any point in time to avoid a voltage collapse. The criterion is general and can be applied to any power system.
Electric Power Systems Research, 2000
The paper presents a novel FACTS concept to improve the dynamic stability of an ac power system. ... more The paper presents a novel FACTS concept to improve the dynamic stability of an ac power system. The concept of parallel ac/dc transmission between two ac systems has been exploited in the scheme presented, using one ac line for both the ac and the dc transmission. A small unit of power is extracted from the system, converted to dc and injected into the ac line through the transformer, neutrals at the two ends to enhance the dynamic stability. The objective of the paper is to introduce the new concept and prove its feasibility. To demonstrate the validity of the proposed method, computer simulated dynamic responses of an ac power system, with and without the controlled dc injection are presented. It has been shown that by using about 2% of ac power transfer, as modulated dc power, substantial system of damping could be achieved.
IET Generation, Transmission & Distribution, 2017
In AC-DC parallel systems, line-commutated-converter (LCC)-based high-voltage direct-current (HVD... more In AC-DC parallel systems, line-commutated-converter (LCC)-based high-voltage direct-current (HVDC) emergency control strategy can improve the stability of the power system. This study proposes an LCC HVDC emergency control strategy that utilises the global information measured by wide-area measurement systems. The design of the proposed LCC HVDC emergency control strategy takes advantage of dynamic surface control and adaptive control. The Lyapunov stability analysis is used to prove that the AC-DC parallel system is uniformly ultimately bounded in the presence of the uncertainties. A two-area four-generator AC-DC parallel system is developed in PSCAD/EMTDC to verify the effectiveness and correctness of the proposed strategy. Simulation results show that the proposed LCC HVDC emergency control strategy can improve the stability of an AC-DC parallel system and is robust. Its superiority is demonstrated by comparing the proposed method with controllers designed using backstepping technique and pole placement technique.
2017 IEEE Electrical Power and Energy Conference (EPEC), 2017
In this paper, Power-Voltage Curves obtained from quasi steady state analysis is used to demonstr... more In this paper, Power-Voltage Curves obtained from quasi steady state analysis is used to demonstrate the concept of voltage stability. This method is shown to be applicable to analyze the voltage stability when the load consists of constant admittance as well as dynamic induction motor loads. The results obtained from quasi steady state analysis is compared with the results of detailed real time simulations. As expected, the paper confirms that quasi steady state analysis can be used to predict the voltage collapse point of radial power systems with reasonable accuracy even when the loads consist of dynamic loads. The simulations and analysis programs developed in the research can be used as teaching tools.
IEEE Transactions on Power Delivery, 2000
... REFERENCES [1] PG McLaren, UD Annakkage, E. Dirks, M. Yu, and AD Parker, Simulation of a dif... more ... REFERENCES [1] PG McLaren, UD Annakkage, E. Dirks, M. Yu, and AD Parker, Simulation of a differential current protection scheme involving mul-tiple current transformers, in ICDS 99, Vasteros, Sweden, May 1999. ... H. Al-Haj and I. El-Amin, IEEE Trans. Power Delivery, vol. ...
2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
Dynamic state estimation is a very important control center application used in the dynamic monit... more Dynamic state estimation is a very important control center application used in the dynamic monitoring of state variables. In transient stability analyses, it is very critical to have accurate and time synchronized measurements with fast reporting rates. This paper presents and validates a time-synchronized phasor measurement unit (PMU)-based for dynamic state estimation by unscented Kalman filter (UKF) method using the real-time digital simulator (RTDS). The UKF algorithm implemented in the dynamic state estimation applies the sigma-point Kalman filter in the estimation of the best location of the measurement in the system state variables. The dynamic state variables of the system are the rotor angle and speed of the generators. The synchrophasor measurment of PMUs are bus voltage magnitudes, phase angles, active, and reactive powers of generators, which are newly applied in the formulated dynamic state estimation for estimate the rotor angle and speed of the generators. The performance of the UKF method is tested with PMU measurements as inputs using the IEEE 14-bus test system. This test system was modeled in the RSCAD software and tested in real time using the RTDS (real-time digital simulator). The dynamic state variables of multi-machine systems are monitored and measured for the study on the transient behavior of power systems.
IEEE Transactions on Power Systems, 2018
More and more system operators are interested in calculating transfer capability in realtime usin... more More and more system operators are interested in calculating transfer capability in realtime using real-time power flow models generated from the Energy Management System (EMS). However, compared to off-line study models, EMS models usually cover only a limited portion of the interconnected system. In most situations, it is not practical to extend the EMS model to capture the impact of the external systems and therefore using an equivalent network becomes necessary. The development of equivalent circuits to represent external areas was a topic discussed over the last 50 years. Almost all of these methods require impedance information about the external area to develop the equivalent circuit. Unfortunately utilities do not have the external impedance information in the real-time. Therefore, normal industry practice is to use off-line studies to develop an equivalent circuit and use that circuit in the real-time operation without any validation. This can result in errors in the security assessment. Therefore, power industry need a method to develop or validate an equivalent circuit based on the available real-time information. This thesis work is focussed on meeting that industry need. The work on this thesis presents two new methods that can be used to generate an equivalent circuit based on the boundary conditions. This method involves calculating
Technology and Economics of Smart Grids and Sustainable Energy, 2016
Analysis of the impact of communication network infrastructure performance on critical power syst... more Analysis of the impact of communication network infrastructure performance on critical power system applications that rely on wide area synchrophasor measurements can be realistically achieved only through cosimulation of the power system and the synchrophasor communication network. In this paper, a single simulation platform, an electromagnetic transient (EMT) simulation program-PSCAD/EMTDC, was used to implement Dinesh Rangana Gurusinghe
IET Generation, Transmission & Distribution, 2016
More and more system operators are interested in calculating transfer capability in real time usi... more More and more system operators are interested in calculating transfer capability in real time using real-time power flow models generated from the energy management system (EMS). However, comparing with off-line study models, EMS models usually cover a limited portion of the interconnected system. It is not practical to extend the EMS model in order to capture the impact of the external systems and as such using an equivalent network becomes necessary for this purpose. Equivalent circuits can be derived from the off-line models for certain predetermined operating conditions. Such fixed equivalent models may produce invalid results under various real-time operating conditions. Hence, it is necessary to derive an equivalent circuit model that is adaptive to the available real-time information. This study presents a new method of creating an equivalent circuit model based on the measured boundary station parameters such as voltages and power flows. Simulation studies show that such derived equivalent circuit models provide solutions with adequate accuracy in comparison with detailed off-line system model.
2009 IEEE Electrical Power & Energy Conference (EPEC), 2009
This paper presents a novel technique for predicting transient stability status of a power system... more This paper presents a novel technique for predicting transient stability status of a power system following a large disturbance. The prediction is based on the synchronously measured samples of the fundamental frequency voltage magnitudes at each generation station. The voltage samples taken immediately after clearing the faults are input to a support vector machine classifier to identify the transient stability
IEEE Transactions on Power Systems, 2011
The paper first shows that the transient stability status of a power system following a large dis... more The paper first shows that the transient stability status of a power system following a large disturbance such as a fault can be early predicted based on the measured post-fault values of the generator voltages, speeds, or rotor angles. Synchronously sampled values provided by phasor measurement units (PMUs) of the generator voltages, frequencies, or rotor angles collected immediately after clearing a fault are used as inputs to a support vector machines (SVM) classifier which predicts the transient stability status. Studies with the New England 39-bus test system and the Venezuelan power network indicated that faster and more accurate predictions can be made by using the post-fault recovery voltage magnitude measurements as inputs. The accuracy and robustness of the transient stability prediction algorithm with the voltage magnitude measurements was extensively tested under both balanced and unbalanced fault conditions, as well as under different operating conditions, presence of measurement errors, voltage sensitive loads, and changes in the network topology. During the various tests carried out using the New England 39-bus test system, the proposed algorithm could always predict when the power system is approaching a transient instability with over 95% success rate.
Profound changes are affecting the economics of the power systems sector such as the emergence of... more Profound changes are affecting the economics of the power systems sector such as the emergence of renewable energy sources and the introduction of energy markets, and these changes impact the knowledge and skill base required of power systems professionals. One area of focus in dealing with these changes is to examine undergraduate power systems engineering curricula, with a view to ensure relevance of content, adjust teaching and learning methods appropriately, and attract and retain students. This is particularly important as the workforce in the field is rapidly approaching the age of retirement, and replenishing this workforce with appropriately equipped engineering graduates is critical for the maintenance of a secure and smoothly operating electrical system. This paper sets the stage for an evaluation of the undergraduate power system curriculum, by outlining the background of evaluation research and describing the evaluation plan proposed for the undergraduate power systems p...
IEEE Open Access Journal of Power and Energy
Leading to the enormous growth in renewable and power electronics technologies and the global dri... more Leading to the enormous growth in renewable and power electronics technologies and the global drive towards environmental friendliness and sustainability, a significant number of renewable energy sources are being connected to the power system via inverter-based systems. The inverter-based generations (IBG) have no stored energy and less fault current injection capability compared to the conventional synchronous machines. Consequently, a large penetration of IBG creates challenges to maintaining the stability of the power system, especially the transient stability. The weaker the power system, the higher the significance of instability. Few solutions exist in the literature to improve the fault recovery of IBG connected to weak power systems. This paper considers the method of storing energy in sub-module capacitors of the Modular-Multi-level Converter (MMC) along with temporarily boosting the inverter's current limit. Conversely, increasing the ratings of the inverter will result in high manufacturing costs. Hence an optimization strategy is proposed in this paper, for obtaining a robust set of inverter control parameters that enhances fault recovery without excessively increasing the manufacturing cost of MMC. A frequency scanning technique supplemented with Generalized Nyquist criteria is incorporated into the optimization methodology to constrain the search space for the optimization algorithm. This enables the optimization algorithm to converge to an acceptable solution with a reasonable computing time. Furthermore, validation of the resultant set of parameters for different system conditions is presented. Finally, IBG with optimized fault recovery controllers is integrated into a simplified real-world power system, and the applicability of the proposed optimized controllers is illustrated.
IEEE Access
This paper proposes a novel three-stage near real-time phase-driven procedure to locate the gener... more This paper proposes a novel three-stage near real-time phase-driven procedure to locate the generator-type source of forced oscillations, inspired by the concept of Transient Energy Function (TEF), independent of the amplitude of any signal. In the commencement of the process, each generation bus is assigned with its active power and angular velocity angles reached from the reduced power system graph. Next, the difference in the synchronous generators' active power angles and the difference in their angular velocity angles is exploited as the graph branches' weight coefficients. Then, three exclusive and first-proposed decision functions are applied sequentially. First, the weighting coefficients of branches and nodes are fed to the first decision function. Regardless of the grid size, the result of this step is limited to up to four generators. The next step focuses exclusively on the first step outcomes, which results in two generators as recommended items. The last step, relying on the output of the second one, reveals the target generator accurately. The methodological procedure has been validated on the New England 10-machine 39-bus benchmark power system modelled in the Real-Time Digital Simulator (RTDS/RSCAD) and then scrutinised in the MATLAB environment. In each study scenario, the results are compared with the conventional transient energy method. The simulation results revealed that the presented approach reliably releases all sources, including limit cycle and turbine governing reference signal modulation, under the most intense parametric resonance.
2018 IEEE Electrical Power and Energy Conference (EPEC), 2018
This paper presents a linearized state-space model of the hybrid cascaded modular multilevel volt... more This paper presents a linearized state-space model of the hybrid cascaded modular multilevel voltage source converter. The developed model is validated against a detailed non-linear Electromagnetic Transient (EMT) simulation model. The impact of the ac system strength on the performance of the converter is investigated for moderately strong and weak systems. An eigenvalue analysis is conducted for both scenarios, with focus on the oscillatory modes present in the system in order to evaluate the stability constraints of the converter when connected to ac networks of different strengths.
IEEE Access, 2020
This paper utilizes modern statistical and machine learning methodology to predict the oscillatio... more This paper utilizes modern statistical and machine learning methodology to predict the oscillation mode of interest in complex power engineering systems. The damping ratio of the electromechanical oscillation mode is formulated as a function of the power of the generators and loads as well as bus voltage magnitudes in the entire power system. The celebrated Lasso algorithm is implemented to solve this highdimension modeling problem. By the nature of the L 1 design, the Lasso algorithm can automatically render a sparse solution, and by eliminating redundant features, it provides desirable prediction power. The resultant model processes a simple structure, and it is easily interpretable. The precision of our sparse modeling framework is demonstrated in the context of an IEEE 50-Generator 145-Bus power network and an online learning framework for the power system oscillation mode prediction is also provided.
Proceedings of International Conference on Intelligent System Application to Power Systems
This paper demonstrates how the simulated annealing algorithm and genetic algorithms can be used ... more This paper demonstrates how the simulated annealing algorithm and genetic algorithms can be used as means to solve the power system unit commitment problem. In addition, this paper presents parallel approaches to speed up the computational requirement of the simulated annealing algorithm. The algorithms were tested with two different problems. The results have demonstrated the success of the algorithms in consistently reaching good solutions.
Optimum power system stabilizer design has been a difficult task due to the nonlinear dynamics of... more Optimum power system stabilizer design has been a difficult task due to the nonlinear dynamics of the synchronous generators. An optimum power system stabilizer which is compensated for the nonlinear operation of the machine is described. A simple linear model of the synchronous machine is obtained at a given operating point by linearizing the nonlinear machine equations. The nonlinear characteristics of the machine are compensated by changing the linear model parameters depending on the prevailing operating condition of the machine. Optimum state feedback gains of the controller are calculated for the different sets of model parameters and scheduled according to the operating state. The algorithm presented can be considered as a generalization of the gain scheduling adaptive algorithms. Machine dynamics for different operating conditions are simulated to evaluate the effectiveness of this algorithm. The results show that the dynamic stability of the system is improved.
POWERCON '98. 1998 International Conference on Power System Technology. Proceedings (Cat. No.98EX151)
This paper presents a strategy for undervoltage load shedding in power systems. An undervoltage l... more This paper presents a strategy for undervoltage load shedding in power systems. An undervoltage load shedding (UVLS) criterion is defined using a generic dynamic load model to determine the amount of load to shed at a given voltage. The 'when and where' for load shedding is determined by identifying the weakest node in the network using a voltage collapse proximity indicator (VCPI). The magnitude of the VCPI is determined by estimating the ratio of the impedance of the load to the Thevenin impedance looking into the network at a given voltage. If required, further load shedding can be carried out by observing the VCPI. The strategy is simple, reliable and can be applied to any power system.
IEE Proceedings - Generation, Transmission and Distribution, 1998
The paper presents a technique for undervoltage load shedding (UVLS) in power systems. The underv... more The paper presents a technique for undervoltage load shedding (UVLS) in power systems. The undervoltage load shedding criterion has been developed using a dynamic load model. The parameters of the dynamic load model are estimated online using a nonlinear least squares technique, namely the Gauss-Newton method. The amount of load to be shed is calculated using the parameters of the dynamic load model. In the event of a voltage unstable situation, the proposed undervoltage load shedding criterion can be used to calculate the minimum amount of load to be shed at any point in time to avoid a voltage collapse. The criterion is general and can be applied to any power system.
Electric Power Systems Research, 2000
The paper presents a novel FACTS concept to improve the dynamic stability of an ac power system. ... more The paper presents a novel FACTS concept to improve the dynamic stability of an ac power system. The concept of parallel ac/dc transmission between two ac systems has been exploited in the scheme presented, using one ac line for both the ac and the dc transmission. A small unit of power is extracted from the system, converted to dc and injected into the ac line through the transformer, neutrals at the two ends to enhance the dynamic stability. The objective of the paper is to introduce the new concept and prove its feasibility. To demonstrate the validity of the proposed method, computer simulated dynamic responses of an ac power system, with and without the controlled dc injection are presented. It has been shown that by using about 2% of ac power transfer, as modulated dc power, substantial system of damping could be achieved.
IET Generation, Transmission & Distribution, 2017
In AC-DC parallel systems, line-commutated-converter (LCC)-based high-voltage direct-current (HVD... more In AC-DC parallel systems, line-commutated-converter (LCC)-based high-voltage direct-current (HVDC) emergency control strategy can improve the stability of the power system. This study proposes an LCC HVDC emergency control strategy that utilises the global information measured by wide-area measurement systems. The design of the proposed LCC HVDC emergency control strategy takes advantage of dynamic surface control and adaptive control. The Lyapunov stability analysis is used to prove that the AC-DC parallel system is uniformly ultimately bounded in the presence of the uncertainties. A two-area four-generator AC-DC parallel system is developed in PSCAD/EMTDC to verify the effectiveness and correctness of the proposed strategy. Simulation results show that the proposed LCC HVDC emergency control strategy can improve the stability of an AC-DC parallel system and is robust. Its superiority is demonstrated by comparing the proposed method with controllers designed using backstepping technique and pole placement technique.
2017 IEEE Electrical Power and Energy Conference (EPEC), 2017
In this paper, Power-Voltage Curves obtained from quasi steady state analysis is used to demonstr... more In this paper, Power-Voltage Curves obtained from quasi steady state analysis is used to demonstrate the concept of voltage stability. This method is shown to be applicable to analyze the voltage stability when the load consists of constant admittance as well as dynamic induction motor loads. The results obtained from quasi steady state analysis is compared with the results of detailed real time simulations. As expected, the paper confirms that quasi steady state analysis can be used to predict the voltage collapse point of radial power systems with reasonable accuracy even when the loads consist of dynamic loads. The simulations and analysis programs developed in the research can be used as teaching tools.
IEEE Transactions on Power Delivery, 2000
... REFERENCES [1] PG McLaren, UD Annakkage, E. Dirks, M. Yu, and AD Parker, Simulation of a dif... more ... REFERENCES [1] PG McLaren, UD Annakkage, E. Dirks, M. Yu, and AD Parker, Simulation of a differential current protection scheme involving mul-tiple current transformers, in ICDS 99, Vasteros, Sweden, May 1999. ... H. Al-Haj and I. El-Amin, IEEE Trans. Power Delivery, vol. ...
2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)
Dynamic state estimation is a very important control center application used in the dynamic monit... more Dynamic state estimation is a very important control center application used in the dynamic monitoring of state variables. In transient stability analyses, it is very critical to have accurate and time synchronized measurements with fast reporting rates. This paper presents and validates a time-synchronized phasor measurement unit (PMU)-based for dynamic state estimation by unscented Kalman filter (UKF) method using the real-time digital simulator (RTDS). The UKF algorithm implemented in the dynamic state estimation applies the sigma-point Kalman filter in the estimation of the best location of the measurement in the system state variables. The dynamic state variables of the system are the rotor angle and speed of the generators. The synchrophasor measurment of PMUs are bus voltage magnitudes, phase angles, active, and reactive powers of generators, which are newly applied in the formulated dynamic state estimation for estimate the rotor angle and speed of the generators. The performance of the UKF method is tested with PMU measurements as inputs using the IEEE 14-bus test system. This test system was modeled in the RSCAD software and tested in real time using the RTDS (real-time digital simulator). The dynamic state variables of multi-machine systems are monitored and measured for the study on the transient behavior of power systems.
IEEE Transactions on Power Systems, 2018
More and more system operators are interested in calculating transfer capability in realtime usin... more More and more system operators are interested in calculating transfer capability in realtime using real-time power flow models generated from the Energy Management System (EMS). However, compared to off-line study models, EMS models usually cover only a limited portion of the interconnected system. In most situations, it is not practical to extend the EMS model to capture the impact of the external systems and therefore using an equivalent network becomes necessary. The development of equivalent circuits to represent external areas was a topic discussed over the last 50 years. Almost all of these methods require impedance information about the external area to develop the equivalent circuit. Unfortunately utilities do not have the external impedance information in the real-time. Therefore, normal industry practice is to use off-line studies to develop an equivalent circuit and use that circuit in the real-time operation without any validation. This can result in errors in the security assessment. Therefore, power industry need a method to develop or validate an equivalent circuit based on the available real-time information. This thesis work is focussed on meeting that industry need. The work on this thesis presents two new methods that can be used to generate an equivalent circuit based on the boundary conditions. This method involves calculating
Technology and Economics of Smart Grids and Sustainable Energy, 2016
Analysis of the impact of communication network infrastructure performance on critical power syst... more Analysis of the impact of communication network infrastructure performance on critical power system applications that rely on wide area synchrophasor measurements can be realistically achieved only through cosimulation of the power system and the synchrophasor communication network. In this paper, a single simulation platform, an electromagnetic transient (EMT) simulation program-PSCAD/EMTDC, was used to implement Dinesh Rangana Gurusinghe
IET Generation, Transmission & Distribution, 2016
More and more system operators are interested in calculating transfer capability in real time usi... more More and more system operators are interested in calculating transfer capability in real time using real-time power flow models generated from the energy management system (EMS). However, comparing with off-line study models, EMS models usually cover a limited portion of the interconnected system. It is not practical to extend the EMS model in order to capture the impact of the external systems and as such using an equivalent network becomes necessary for this purpose. Equivalent circuits can be derived from the off-line models for certain predetermined operating conditions. Such fixed equivalent models may produce invalid results under various real-time operating conditions. Hence, it is necessary to derive an equivalent circuit model that is adaptive to the available real-time information. This study presents a new method of creating an equivalent circuit model based on the measured boundary station parameters such as voltages and power flows. Simulation studies show that such derived equivalent circuit models provide solutions with adequate accuracy in comparison with detailed off-line system model.
2009 IEEE Electrical Power & Energy Conference (EPEC), 2009
This paper presents a novel technique for predicting transient stability status of a power system... more This paper presents a novel technique for predicting transient stability status of a power system following a large disturbance. The prediction is based on the synchronously measured samples of the fundamental frequency voltage magnitudes at each generation station. The voltage samples taken immediately after clearing the faults are input to a support vector machine classifier to identify the transient stability
IEEE Transactions on Power Systems, 2011
The paper first shows that the transient stability status of a power system following a large dis... more The paper first shows that the transient stability status of a power system following a large disturbance such as a fault can be early predicted based on the measured post-fault values of the generator voltages, speeds, or rotor angles. Synchronously sampled values provided by phasor measurement units (PMUs) of the generator voltages, frequencies, or rotor angles collected immediately after clearing a fault are used as inputs to a support vector machines (SVM) classifier which predicts the transient stability status. Studies with the New England 39-bus test system and the Venezuelan power network indicated that faster and more accurate predictions can be made by using the post-fault recovery voltage magnitude measurements as inputs. The accuracy and robustness of the transient stability prediction algorithm with the voltage magnitude measurements was extensively tested under both balanced and unbalanced fault conditions, as well as under different operating conditions, presence of measurement errors, voltage sensitive loads, and changes in the network topology. During the various tests carried out using the New England 39-bus test system, the proposed algorithm could always predict when the power system is approaching a transient instability with over 95% success rate.