[1] K. Mansour, M. Maghsoud, N. Daryoosh, and T. Behrouz, "Transient Stability Enhancement by DSSC with Fuzzy Supplementary Controller," Journal of Electrical Engineering & Technology, vol. 5, no. 3, pp. 415-422, Sept.2010.
Abstract: The distributed flexible alternative current transmission system (D-FACTS) is a recently developed FACTS technology. Distributed Static Series Compensator (DSSC) is one example of D-FACTS devices. DSSC functions in the same way as a Static Synchronous Series Compensator (SSSC), but is smaller in size, lower in price, and possesses more capabilities. Likewise, DSSC lies in transmission lines in a distributed manner. In this work, we designed a fuzzy logic controller to use the DSSC for enhancing transient stability in a two-machine, two-area power system. The parameters of the fuzzy logic controller are varied widely by a suitable choice of membership function and parameters in the rule base. Simulation results demonstrate the effectiveness of the fuzzy controller for transient stability enhancement by DSSC
Abstract: The distributed flexible alternative current transmission system (D-FACTS) is a recently developed FACTS technology. Distributed Static Series Compensator (DSSC) is one example of D-FACTS devices. DSSC functions in the same way as a Static Synchronous Series Compensator (SSSC), but is smaller in size, lower in price, and possesses more capabilities. Likewise, DSSC lies in transmission lines in a distributed manner. In this work, we designed a fuzzy logic controller to use the DSSC for enhancing transient stability in a two-machine, two-area power system. The parameters of the fuzzy logic controller are varied widely by a suitable choice of membership function and parameters in the rule base. Simulation results demonstrate the effectiveness of the fuzzy controller for transient stability enhancement by DSSC
[2] N. Karpagam, D. Devaraj, and P. Subbaraj, "Improved fuzzy logic controller for SVC in power system damping using global signals," Electrical Engineering, vol. 91, no. 7, pp. 395-404, Mar.2010.
Abstract: Static Var Compensator (SVC) is a shunt-type FACTS device, which is used in power systems primarily for the purpose of voltage and reactive power control. In this paper, an improved fuzzy logic-based supplementary controller for SVC is developed for damping the rotor angle oscillations and to improve the stability of the power system. The generator speed and the electrical power are chosen as global input signals for the proposed fuzzy logic controller (FLC). The effectiveness and feasibility of the proposed control is demonstrated with single-machine infinite bus (SMIB) system, three-machine nine-bus WSCC system and New England 10-machine system, which shows the improvement over the use of a fixed parameter controller and existing FLC
Abstract: Static Var Compensator (SVC) is a shunt-type FACTS device, which is used in power systems primarily for the purpose of voltage and reactive power control. In this paper, an improved fuzzy logic-based supplementary controller for SVC is developed for damping the rotor angle oscillations and to improve the stability of the power system. The generator speed and the electrical power are chosen as global input signals for the proposed fuzzy logic controller (FLC). The effectiveness and feasibility of the proposed control is demonstrated with single-machine infinite bus (SMIB) system, three-machine nine-bus WSCC system and New England 10-machine system, which shows the improvement over the use of a fixed parameter controller and existing FLC
[3] M. A. Abido, "Power System Stability Enhancement Using Facts Controllers: A Review," Arabian Journal for Science and Engineering, vol. 34, no. 1B, pp. 153-172, Apr.2009.
Abstract: In recent years, power demand has increased substantially while the expansion of power generation and transmission has been severely limited due to limited resources and environmental restrictions. As a consequence, some transmission lines are heavily loaded and the system stability becomes a power transfer-limiting factor. Flexible AC transmission systems (FACTS) controllers have been mainly used for solving various power system steady state control problems. However, recent studies reveal that FACTS controllers could be employed to enhance power system stability in addition to their main function of power flow control. The literature shows an increasing interest in this subject for the last two decades, where the enhancement of system stability using FACTS controllers has been extensively investigated. This paper presents a comprehensive review on the research and developments in the power system stability enhancement using FACTS damping controllers. Several technical issues related to FACTS installations have been highlighted and performance comparison of different FACTS controllers has been discussed. In addition, some of the utility experience, real-world installations, and semiconductor technology development have been reviewed and summarized. Applications of FACTS to other power system studies have also been discussed. About two hundred twenty seven research publications have been classified and appended for a quick reference
Abstract: In recent years, power demand has increased substantially while the expansion of power generation and transmission has been severely limited due to limited resources and environmental restrictions. As a consequence, some transmission lines are heavily loaded and the system stability becomes a power transfer-limiting factor. Flexible AC transmission systems (FACTS) controllers have been mainly used for solving various power system steady state control problems. However, recent studies reveal that FACTS controllers could be employed to enhance power system stability in addition to their main function of power flow control. The literature shows an increasing interest in this subject for the last two decades, where the enhancement of system stability using FACTS controllers has been extensively investigated. This paper presents a comprehensive review on the research and developments in the power system stability enhancement using FACTS damping controllers. Several technical issues related to FACTS installations have been highlighted and performance comparison of different FACTS controllers has been discussed. In addition, some of the utility experience, real-world installations, and semiconductor technology development have been reviewed and summarized. Applications of FACTS to other power system studies have also been discussed. About two hundred twenty seven research publications have been classified and appended for a quick reference
[4] S. K. Yee and J. V. Milanovic, "Fuzzy Logic Controller for Decentralized Stabilization of Multimachine Power Systems," Ieee Transactions on Fuzzy Systems, vol. 16, no. 4, pp. 971-981, Aug.2008.
Abstract: Although fuzzy logic has been successfully implemented in many industries, the acceptance of fuzzy logic within the power industry has met with limited success due to the requirement for prior information about an extremely complex system. A decentralized fuzzy logic controller (FLC) proposed in this paper has been designed, however, using a systematic analytical method based on a performance index in order to bypass the need for prior knowledge about the system. The proposed FLC tracks speed deviations to zero in order to stabilize the power output of the generator, while, at the same time, it controls and stabilizes the terminal voltage of the generator. This paper introduces an analytical method for the design of an FLC that successfully stabilizes both voltage and power oscillations following small and large disturbances in a power system. Simulations are performed with a multimachine power system, which includes a four-machine and a ten-machine (New England) system. The results obtained clearly demonstrate the effectiveness of designed FLCs in stabilizing the system. The responses of the system with FLCs are also compared with those obtained using classical power system stabilizers (PSSs) tuned by a conventional linear sequential tuning method (LSM) and optimization-based method
Abstract: Although fuzzy logic has been successfully implemented in many industries, the acceptance of fuzzy logic within the power industry has met with limited success due to the requirement for prior information about an extremely complex system. A decentralized fuzzy logic controller (FLC) proposed in this paper has been designed, however, using a systematic analytical method based on a performance index in order to bypass the need for prior knowledge about the system. The proposed FLC tracks speed deviations to zero in order to stabilize the power output of the generator, while, at the same time, it controls and stabilizes the terminal voltage of the generator. This paper introduces an analytical method for the design of an FLC that successfully stabilizes both voltage and power oscillations following small and large disturbances in a power system. Simulations are performed with a multimachine power system, which includes a four-machine and a ten-machine (New England) system. The results obtained clearly demonstrate the effectiveness of designed FLCs in stabilizing the system. The responses of the system with FLCs are also compared with those obtained using classical power system stabilizers (PSSs) tuned by a conventional linear sequential tuning method (LSM) and optimization-based method
[5] M. H. Ali, T. Murata, and J. Tamura, "Influence of Communication Delay on the Performance of Fuzzy Logic-Controlled Braking Resistor Against Transient Stability," Ieee Transactions on Control Systems Technology, vol. 16, no. 6, pp. 1232-1241, Nov.2008.
Abstract: This paper analyzes the influence of communication delays introduced in online calculation of the global input variable of the fuzzy logic controller for braking resistor (BR) switching on the transient stability of a multi-machine power system. The time derivative of the total kinetic energy deviation (D) of the synchronous generators is used as the global input of the fuzzy logic controller in this work. The Global Positioning System (GPS) is proposed for the practical implementation of the calculation of the global input of the fuzzy controller. Communication delays may affect the control system, and consequently, the transient stability of the power system also. A prediction function is proposed to minimize the negative effect caused by the communication delay on the transient stability. Also, the performance of the fuzzy logic-controlled BR is compared to that of the conventional proportional-integral (PI) controlled BR. Simulation results of both balanced and unbalanced faults at different points in the system show that the communication delay associated with the fuzzy controller input calculation has an influence on the transient stability. Moreover, the negative effect caused by the communication delay on the transient stability enhancement using fuzzy-controlled BR can be minimized by the prediction method. Also, the performance of the fuzzy logic-controlled BR is better than that of the PI-controlled BR
Abstract: This paper analyzes the influence of communication delays introduced in online calculation of the global input variable of the fuzzy logic controller for braking resistor (BR) switching on the transient stability of a multi-machine power system. The time derivative of the total kinetic energy deviation (D) of the synchronous generators is used as the global input of the fuzzy logic controller in this work. The Global Positioning System (GPS) is proposed for the practical implementation of the calculation of the global input of the fuzzy controller. Communication delays may affect the control system, and consequently, the transient stability of the power system also. A prediction function is proposed to minimize the negative effect caused by the communication delay on the transient stability. Also, the performance of the fuzzy logic-controlled BR is compared to that of the conventional proportional-integral (PI) controlled BR. Simulation results of both balanced and unbalanced faults at different points in the system show that the communication delay associated with the fuzzy controller input calculation has an influence on the transient stability. Moreover, the negative effect caused by the communication delay on the transient stability enhancement using fuzzy-controlled BR can be minimized by the prediction method. Also, the performance of the fuzzy logic-controlled BR is better than that of the PI-controlled BR
[6] S. M. Muyeen, R. Takahashi, M. H. Ali, T. Murata, and J. Tamura, "Transient stability augmentation of power system including wind farms by using ECS," Ieee Transactions on Power Systems, vol. 23, no. 3, pp. 1179-1187, Aug.2008.
Abstract: This paper presents a new method to enhance the transient stability of multimachine power system including wind farms, when a severe network disturbance occurs in the power system. For this purpose, the energy capacitor system (ECS) composed of power electronic devices and electric double layer capacitor (EDLC) is proposed. The control scheme of ECS is based on a sinusoidal PWM voltage source converter (VSC) and fuzzy logic controlled dc-dc buck/boost converter using insulated gate bipolar transistors (IGBT). Two wind farms are considered to be connected to the power system. Two-mass drive train model of wind turbine generator system (WTGS) is used in the analyses as the drive train modeling has great influence on the dynamic characteristics of WTGS. Real wind speed data are used in the analyses to obtain realistic responses. Different types of symmetrical and unsymmetrical faults are considered as the network disturbance. Simulation results clearly show that the proposed ECS can enhance the transient stability of wind generators in multimachine power system as well as their low voltage ride through (LVRT) capability
Abstract: This paper presents a new method to enhance the transient stability of multimachine power system including wind farms, when a severe network disturbance occurs in the power system. For this purpose, the energy capacitor system (ECS) composed of power electronic devices and electric double layer capacitor (EDLC) is proposed. The control scheme of ECS is based on a sinusoidal PWM voltage source converter (VSC) and fuzzy logic controlled dc-dc buck/boost converter using insulated gate bipolar transistors (IGBT). Two wind farms are considered to be connected to the power system. Two-mass drive train model of wind turbine generator system (WTGS) is used in the analyses as the drive train modeling has great influence on the dynamic characteristics of WTGS. Real wind speed data are used in the analyses to obtain realistic responses. Different types of symmetrical and unsymmetrical faults are considered as the network disturbance. Simulation results clearly show that the proposed ECS can enhance the transient stability of wind generators in multimachine power system as well as their low voltage ride through (LVRT) capability
[7] A. Kahouli, T. Guesmi, H. H. Abdallah, and O. Abderrazak, "Fuzzy control approach for monomachine power systems," International Review of Electrical Engineering-Iree, vol. 2, no. 5, pp. 638-647, Sept.2007.
Abstract: Electrical power system angle stability can be improved by a wide variety of controls. Some methods have been used effectively for many years, both at generating plants and in transmission network. In this paper, a fuzzy control strategy for stabilization of the transient faulted power system is presented. The first step is to find the critical clearing time (CCT) by equal area stability criterion and numerical integration. The second interests to fuzzy logic controller. For this last step, we present the nonlinear model with a Takogi-Sugeno fuzzy model (TS). Then, a model-based in fuzzy controller design utilizing the concept of the so-called "Parallel Distributed Compensation" (PDC) is employed Stability analysis and control design problems can be reduced to linear matrix inequality (LMI) problems. Therefore, they can be solved efficiently in practice by convex programming techniques for LMI's. A single machine infinite bits system is analysed ivith the proposed methods.
Abstract: Electrical power system angle stability can be improved by a wide variety of controls. Some methods have been used effectively for many years, both at generating plants and in transmission network. In this paper, a fuzzy control strategy for stabilization of the transient faulted power system is presented. The first step is to find the critical clearing time (CCT) by equal area stability criterion and numerical integration. The second interests to fuzzy logic controller. For this last step, we present the nonlinear model with a Takogi-Sugeno fuzzy model (TS). Then, a model-based in fuzzy controller design utilizing the concept of the so-called "Parallel Distributed Compensation" (PDC) is employed Stability analysis and control design problems can be reduced to linear matrix inequality (LMI) problems. Therefore, they can be solved efficiently in practice by convex programming techniques for LMI's. A single machine infinite bits system is analysed ivith the proposed methods.
[8] M. H. Ali, T. Murata, and J. Tamura, "A fuzzy logic-controlled superconducting magnetic energy storage for transient stability augmentation," Ieee Transactions on Control Systems Technology, vol. 15, no. 1, pp. 144-150, Jan.2007.
Abstract: This paper presents a fuzzy logic-controlled superconducting magnetic energy storage (SMES) to improve the transient stability of an electric power system. In order to see how effective the proposed fuzzy controlled SMES in improving the transient stability is, its performance is compared to that of a conventional proportional-integral (PI) controlled SMES. Furthermore, a comparative study between the fuzzy controlled SMES and fuzzy controlled braking resistor (BR) is carried out. Simulation results show that the performance of fuzzy controlled SMES is better than that of PI controlled SMES. Again, the performance of SMES is better than that of BR. Finally, it can be concluded that the proposed fuzzy controlled SMES provides a very simple and effective means of transient stability enhancement of electric power systems
Abstract: This paper presents a fuzzy logic-controlled superconducting magnetic energy storage (SMES) to improve the transient stability of an electric power system. In order to see how effective the proposed fuzzy controlled SMES in improving the transient stability is, its performance is compared to that of a conventional proportional-integral (PI) controlled SMES. Furthermore, a comparative study between the fuzzy controlled SMES and fuzzy controlled braking resistor (BR) is carried out. Simulation results show that the performance of fuzzy controlled SMES is better than that of PI controlled SMES. Again, the performance of SMES is better than that of BR. Finally, it can be concluded that the proposed fuzzy controlled SMES provides a very simple and effective means of transient stability enhancement of electric power systems
[9] M. H. Ali, T. Murata, and J. Tamura, "Effect of coordination of optimal reclosing and fuzzy controlled braking resistor on transient stability during unsuccessful reclosing," Ieee Transactions on Power Systems, vol. 21, no. 3, pp. 1321-1330, Aug.2006.
Abstract: This paper analyzes the effect of the coordination of optimal reclosing and fuzzy logic-controlled braking resistor on the transient stability of a multimachine power system in case of an unsuccessful reclosing of circuit breakers. The transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is compared to that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor. The effectiveness of the proposed method is confirmed by simulations in case of a nine-bus power system model as well as a ten-machine system. Simulation results of both balanced and unbalanced faults at different points in the power systems show that the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is able to stabilize the systems well in case of an unsuccessful reclosing. Moreover, the transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is better than that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor
Abstract: This paper analyzes the effect of the coordination of optimal reclosing and fuzzy logic-controlled braking resistor on the transient stability of a multimachine power system in case of an unsuccessful reclosing of circuit breakers. The transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is compared to that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor. The effectiveness of the proposed method is confirmed by simulations in case of a nine-bus power system model as well as a ten-machine system. Simulation results of both balanced and unbalanced faults at different points in the power systems show that the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is able to stabilize the systems well in case of an unsuccessful reclosing. Moreover, the transient stability performance of the coordinated operation of optimal reclosing and fuzzy controlled braking resistor is better than that of the coordinated operation of conventional auto-reclosing and fuzzy controlled braking resistor
[10] S. Mishra, "Hybrid-neuro-fuzzy UPFC for improving transient stability performance of power system," Electric Power Components and Systems, vol. 33, no. 1, pp. 73-84, Jan.2005.
Abstract: This article presents a new technique of combining the advantages of both conventional proportional and integral (PI) controller with a radial basis function neural network (RBFNN) with Takagi-Sugeno (TS) fuzzy updating of its parameters. The error is given as input to the RBFNN, which in turn outputs a modified error to be used by the PI controller. This control scheme is used for controlling the series voltage injection through unified power flow controller (UPFC) to improve the modal oscillations of a multi-machine power system. Further, a new local auxiliary signal derived from phase angle difference across the UPFC series transformer is added to the real power error to improve the damping performance. This eliminates the need of generator speed mostly used for improving modal oscillation damping. Besides, all the machines are being equipped with conventional power system stabilizer (PSS) to study the coordinated effect of UPFC and PSS in the system. Digital simulation of a four machine power system subjected to a wide variety of disturbances validates the efficiency of the new approach
Abstract: This article presents a new technique of combining the advantages of both conventional proportional and integral (PI) controller with a radial basis function neural network (RBFNN) with Takagi-Sugeno (TS) fuzzy updating of its parameters. The error is given as input to the RBFNN, which in turn outputs a modified error to be used by the PI controller. This control scheme is used for controlling the series voltage injection through unified power flow controller (UPFC) to improve the modal oscillations of a multi-machine power system. Further, a new local auxiliary signal derived from phase angle difference across the UPFC series transformer is added to the real power error to improve the damping performance. This eliminates the need of generator speed mostly used for improving modal oscillation damping. Besides, all the machines are being equipped with conventional power system stabilizer (PSS) to study the coordinated effect of UPFC and PSS in the system. Digital simulation of a four machine power system subjected to a wide variety of disturbances validates the efficiency of the new approach
[11] M. H. Ali, T. Murata, and J. Tamura, "The effect of temperature rise of the fuzzy logic-controlled braking resistors on transient stability," Ieee Transactions on Power Systems, vol. 19, no. 2, pp. 1085-1095, May2004.
Abstract: Braking resistor is a very powerful tool to improve transient stability in a power system. Usually, a fixed value, of the braking resistor is considered for the transient stability analysis. However, when the braking resistor is in operation, temperature of the resistor material rises above ambient temperature which ultimately causes the resistance value to increase. This paper analyzes the effect of the temperature rise of the fuzzy logic-controlled braking resistor on the transient stability in a multimachine power system. The performance of the braking resistor scheme with fuzzy controller is compared to that of with conventional proportional-integral-derivative (PID) controller. Simulation results of both balanced and unbalanced faults at different points in the system indicate that the temperature rise of the fuzzy logic-controlled braking resistors has little or almost no effect on the transient stability of the multimachine power system. Moreover, it is found that the performance of fuzzy logic controller is better than that of conventional PID controller. Thus, the proposed fuzzy control strategy provides a simple and effective method of transient stability enhancement
Abstract: Braking resistor is a very powerful tool to improve transient stability in a power system. Usually, a fixed value, of the braking resistor is considered for the transient stability analysis. However, when the braking resistor is in operation, temperature of the resistor material rises above ambient temperature which ultimately causes the resistance value to increase. This paper analyzes the effect of the temperature rise of the fuzzy logic-controlled braking resistor on the transient stability in a multimachine power system. The performance of the braking resistor scheme with fuzzy controller is compared to that of with conventional proportional-integral-derivative (PID) controller. Simulation results of both balanced and unbalanced faults at different points in the system indicate that the temperature rise of the fuzzy logic-controlled braking resistors has little or almost no effect on the transient stability of the multimachine power system. Moreover, it is found that the performance of fuzzy logic controller is better than that of conventional PID controller. Thus, the proposed fuzzy control strategy provides a simple and effective method of transient stability enhancement
[12] N. Yadaiah, A. G. D. Kumar, and J. L. Bhattacharya, "Fuzzy based coordinated controller for power system stability and voltage regulation," Electric Power Systems Research, vol. 69, no. 2-3, pp. 169-177, May2004.
Abstract: This paper deals with the design of a fuzzy based coordinated controller to prevent an electric power system losing synchronism after a large sudden fault and to achieve good post-fault voltage level. The developed controller has a fuzzy logic unit (FLU) which, accepts change in terminal voltage and speed deviation as its inputs and generates the required weightage for the transient controller and voltage controller. The performance of the proposed controller is compared with those existing control switching coordinate controller. The simulation study is carried out for the configuration of a single machine infinite bus power system.
Abstract: This paper deals with the design of a fuzzy based coordinated controller to prevent an electric power system losing synchronism after a large sudden fault and to achieve good post-fault voltage level. The developed controller has a fuzzy logic unit (FLU) which, accepts change in terminal voltage and speed deviation as its inputs and generates the required weightage for the transient controller and voltage controller. The performance of the proposed controller is compared with those existing control switching coordinate controller. The simulation study is carried out for the configuration of a single machine infinite bus power system.
[13] A. H. M. A. Rahim, "A minimum-time based fuzzy logic dynamic braking resistor control for sub-synchronous resonance," International Journal of Electrical Power & Energy Systems, vol. 26, no. 3, pp. 191-198, Mar.2004.
Abstract: Dynamically switched resistor banks connected to the generator transformer bus are known to improve transient stability of the power system. In this article, a braking resistor control strategy designed through fuzzy logic control theory has been proposed to damp the slowly growing sub-synchronous resonant (SSR) frequency oscillations of a power system. The proposed control has been tested on the IEEE second benchmark model for SSR studies. A fuzzy logic controller designed through a classical minimum-time strategy was compared with a general fuzzy strategy employing generator speed variation and acceleration as input to the controller. It was observed that the proposed minimum-time based fuzzy controller provides better damping control; and it is computationally very efficient.
Abstract: Dynamically switched resistor banks connected to the generator transformer bus are known to improve transient stability of the power system. In this article, a braking resistor control strategy designed through fuzzy logic control theory has been proposed to damp the slowly growing sub-synchronous resonant (SSR) frequency oscillations of a power system. The proposed control has been tested on the IEEE second benchmark model for SSR studies. A fuzzy logic controller designed through a classical minimum-time strategy was compared with a general fuzzy strategy employing generator speed variation and acceleration as input to the controller. It was observed that the proposed minimum-time based fuzzy controller provides better damping control; and it is computationally very efficient.
[14] Q. Gu, A. Pandey, and S. K. Starrett, "Fuzzy logic control schemes for static VAR compensator to control system damping using global signal," Electric Power Systems Research, vol. 67, no. 2, pp. 115-122, Nov.2003.
Abstract: This paper presents a simple way of achieving damping of phase angle oscillations and improving transient stability of an interconnected power system network using fuzzy logic. The output of the fuzzy logic controller is fed to an already existing Static VAR compensator (SVC). Different input measurements and their combinations are tested and the effectiveness of the fuzzy controller for achieving stability has been demonstrated on a four-generator, two-area system using simulation studies. The inputs tested are line power, angular speed, machine angle, frequency and combination of these. The paper also compares the damping effectiveness of the fuzzy controlled SVC (FCS) and a conventional power system stabilizer (CPSS).
Abstract: This paper presents a simple way of achieving damping of phase angle oscillations and improving transient stability of an interconnected power system network using fuzzy logic. The output of the fuzzy logic controller is fed to an already existing Static VAR compensator (SVC). Different input measurements and their combinations are tested and the effectiveness of the fuzzy controller for achieving stability has been demonstrated on a four-generator, two-area system using simulation studies. The inputs tested are line power, angular speed, machine angle, frequency and combination of these. The paper also compares the damping effectiveness of the fuzzy controlled SVC (FCS) and a conventional power system stabilizer (CPSS).
[15] S. Mishra, P. K. Dash, P. K. Hota, and M. Tripathy, "Genetically optimized neuro-fuzzy IPFC for damping modal oscillations of power system," Ieee Transactions on Power Systems, vol. 17, no. 4, pp. 1140-1147, Nov.2002.
Abstract: An integrated approach of radial basis function neural network (RBFNN) and Takagi-Sugeno (TS) fuzzy scheme with a genetic optimization of their parameters has been developed in this paper to design intelligent adaptive controllers for improving the transient stability performance of power systems. At the outset, this concept is applied to a simple device such as thyristor-controlled series capacitor (TCSC) connected in a single-machine infinite bus power system and is then extended to interline power-flow controller (IPFC) connected in a multimachine power system. The RBFNN uses single neuron architecture and its parameters are dynamically updated in an online fashion with TS-fuzzy scheme designed with only four rules and triangular membership function. The rules of the TS-fuzzy scheme are derived from the real- or reactive-power error and their derivatives either at the TCSC or IPFC buses depending on the device. Further, to implement this combined scheme only one coefficient in the TS-fuzzy rules needs to be optimized. The optimization of this coefficient as well as the coefficient for auxiliary signal generation is performed through genetic algorithm. The performance of the new controller is evaluated in single-machine and multimachine power systems subjected to various transient disturbances. The new genetic-neuro-fuzzy control scheme exhibits a superior damping performance as well as a greater critical clearing time in comparison to the existing PI and RBFNN controller with updating of its parameters through the extended Kalman filter (EKF). Its simple architecture reduces the computational burden, thereby making it attractive for real-time implementation
Abstract: An integrated approach of radial basis function neural network (RBFNN) and Takagi-Sugeno (TS) fuzzy scheme with a genetic optimization of their parameters has been developed in this paper to design intelligent adaptive controllers for improving the transient stability performance of power systems. At the outset, this concept is applied to a simple device such as thyristor-controlled series capacitor (TCSC) connected in a single-machine infinite bus power system and is then extended to interline power-flow controller (IPFC) connected in a multimachine power system. The RBFNN uses single neuron architecture and its parameters are dynamically updated in an online fashion with TS-fuzzy scheme designed with only four rules and triangular membership function. The rules of the TS-fuzzy scheme are derived from the real- or reactive-power error and their derivatives either at the TCSC or IPFC buses depending on the device. Further, to implement this combined scheme only one coefficient in the TS-fuzzy rules needs to be optimized. The optimization of this coefficient as well as the coefficient for auxiliary signal generation is performed through genetic algorithm. The performance of the new controller is evaluated in single-machine and multimachine power systems subjected to various transient disturbances. The new genetic-neuro-fuzzy control scheme exhibits a superior damping performance as well as a greater critical clearing time in comparison to the existing PI and RBFNN controller with updating of its parameters through the extended Kalman filter (EKF). Its simple architecture reduces the computational burden, thereby making it attractive for real-time implementation
[16] J. L. Munda and H. Miyagi, "Stability analysis and control of a wind turbine-driven induction generator," Electric Power Components and Systems, vol. 30, no. 12, pp. 1223-1233, Dec.2002.
Abstract: This article presents the details of various methods of analysis suitable for dynamic and transient stability analysis of an induction generator-infinite bus power system, under various control strategies. The mechanical torque of the generator is obtained from a pitch-controlled wind turbine. Self-excitation of the induction generator is from a terminal capacitor, the value of which is also controlled. Step-by-step simulation studies are performed under conventional control methods. Fuzzy logic control is then introduced in the control of the terminal capacitor and the wind turbine blade pitch angle
Abstract: This article presents the details of various methods of analysis suitable for dynamic and transient stability analysis of an induction generator-infinite bus power system, under various control strategies. The mechanical torque of the generator is obtained from a pitch-controlled wind turbine. Self-excitation of the induction generator is from a terminal capacitor, the value of which is also controlled. Step-by-step simulation studies are performed under conventional control methods. Fuzzy logic control is then introduced in the control of the terminal capacitor and the wind turbine blade pitch angle
[17] T. S. Chung and D. Z. Fang, "Fuzzy logic controller for enhancing oscillatory stability of AC/DC interconnected power system," Electric Power Systems Research, vol. 61, no. 3, pp. 221-226, Apr.2002.
Abstract: A novel control strategy is developed for High Voltage DC (HVDC) links to improve oscillatory stability of interconnected power systems. An 'area' principle is proposed for controller design to damp AC tie power oscillations by increasing the oscillatory 'deceleration area'. Exploiting fast control capability of HVDC link, a fuzzy-rule is adopted to smooth the power transition for reducing power 'shock' to power system. The strategy also incorporates adaptive control techniques to prevent tie-link power 'chattering'. Simulation results using the proposed control scheme on two typical power systems are presented. The results demonstrate that significant improvements in both oscillatory and transient stability are obtained.
Abstract: A novel control strategy is developed for High Voltage DC (HVDC) links to improve oscillatory stability of interconnected power systems. An 'area' principle is proposed for controller design to damp AC tie power oscillations by increasing the oscillatory 'deceleration area'. Exploiting fast control capability of HVDC link, a fuzzy-rule is adopted to smooth the power transition for reducing power 'shock' to power system. The strategy also incorporates adaptive control techniques to prevent tie-link power 'chattering'. Simulation results using the proposed control scheme on two typical power systems are presented. The results demonstrate that significant improvements in both oscillatory and transient stability are obtained.
[18] M. A. L. Badr, F. A. Khalifa, S. A. Gawish, and W. Sabry, "Large-scale power system transient and dynamic stability using delayed-operation FLPSS-AVR controller coordination," Canadian Journal of Electrical and Computer Engineering-Revue Canadienne de Genie Electrique et Informatique, vol. 26, no. 2, pp. 61-64, Apr.2001.
Abstract: This paper presents a coordinated control structure comprising a fuzzy logic power system stabilizer (FLPSS) and an automatic voltage regulator (AVR) for stability enhancement of a large-scale power system. The FLPSS is applied to certain machines in the system, while the others are equipped with the AVR only. Delaying the operation of the FLPSS for a short period after the occurrence of a disturbance makes possible coordination of the interaction of the FLPSS and the AVR. The application of this delayed coordination has proven its success in the damping of large-scale power system oscillations. I order to achieve the best possible damping characteristics, two signals are chosen as inputs to the FLPSS: the deviation of power angle derivative (Delta(delta) over dot) and the deviation of speed derivative (Delta(omega) over dot) of the synchronous machine: while the deviation of terminal voltage (A nu (t)) signal is chosen to be the input of the AVR. These variables have efficient effects on the damping of the oscillations of both frequency and terminal voltage. The effectiveness of this delayed FLPSS-AVR coordination is demonstrated by a digital computer simulation of a large-scale power system
Abstract: This paper presents a coordinated control structure comprising a fuzzy logic power system stabilizer (FLPSS) and an automatic voltage regulator (AVR) for stability enhancement of a large-scale power system. The FLPSS is applied to certain machines in the system, while the others are equipped with the AVR only. Delaying the operation of the FLPSS for a short period after the occurrence of a disturbance makes possible coordination of the interaction of the FLPSS and the AVR. The application of this delayed coordination has proven its success in the damping of large-scale power system oscillations. I order to achieve the best possible damping characteristics, two signals are chosen as inputs to the FLPSS: the deviation of power angle derivative (Delta(delta) over dot) and the deviation of speed derivative (Delta(omega) over dot) of the synchronous machine: while the deviation of terminal voltage (A nu (t)) signal is chosen to be the input of the AVR. These variables have efficient effects on the damping of the oscillations of both frequency and terminal voltage. The effectiveness of this delayed FLPSS-AVR coordination is demonstrated by a digital computer simulation of a large-scale power system
[19] L. O. Mak, Y. X. Ni, and C. M. Shen, "STATCOM with fuzzy controllers for interconnected power systems," Electric Power Systems Research, vol. 55, no. 2, pp. 87-95, Aug.2000.
Abstract: In this paper, the fuzzy controller is designed for static synchronous compensator (STATCOM) to enhance interconnected power system stability. The power frequency model for STATCOM with conventional controllers is presented first. Fuzzy controllers are then designed for both main and supplementary controllers of the STATCOM. The fuzzy main control is constant voltage control with voltage regulation which aims at providing voltage support on the tie lines of interconnected power systems to enhance transient stability and increase transfer limit. The fuzzy supplementary control (SC) is designed for damping interarea power oscillation and enhancing dynamic stability of interconnected power systems. The integrated STATCOM model has been incorporated to the small signal stability and transient stability programs with a novel interface. Computer tests are conducted on a four-generator test system. The results show that STATCOM can enhance system transfer limit and improve system dynamic behavior significantly. Computer results also show that the performance of fuzzy controllers is fairly well and possesses good robustness.
Abstract: In this paper, the fuzzy controller is designed for static synchronous compensator (STATCOM) to enhance interconnected power system stability. The power frequency model for STATCOM with conventional controllers is presented first. Fuzzy controllers are then designed for both main and supplementary controllers of the STATCOM. The fuzzy main control is constant voltage control with voltage regulation which aims at providing voltage support on the tie lines of interconnected power systems to enhance transient stability and increase transfer limit. The fuzzy supplementary control (SC) is designed for damping interarea power oscillation and enhancing dynamic stability of interconnected power systems. The integrated STATCOM model has been incorporated to the small signal stability and transient stability programs with a novel interface. Computer tests are conducted on a four-generator test system. The results show that STATCOM can enhance system transfer limit and improve system dynamic behavior significantly. Computer results also show that the performance of fuzzy controllers is fairly well and possesses good robustness.
[20] B. H. Li, Q. H. Wu, P. Y. Wang, and X. X. Zhou, "Learning-coordinated fuzzy logic control of dynamic quadrature boosters in multi-machine power systems," Iee Proceedings-Generation Transmission and Distribution, vol. 146, no. 6, pp. 577-585, Nov.1999.
Abstract: A learning-coordinated fuzzy logic control (LCFLC) strategy is investigated for the control of dynamic quadrature boosters (DQBs) installed distributively in a large-scale power system to enhance the power system stability. In this strategy, a reinforcement learning technique is employed to search for optimal parameters of the fuzzy logic controllers according to a given performance index, to control the DQBs in a coordinated fashion. A simulation study is undertaken in a thirteen-machine power system. The simulation results show that the LCFLC can be used as an online control strategy to give coordination of the locally installed DQBs to improve the power system stability
Abstract: A learning-coordinated fuzzy logic control (LCFLC) strategy is investigated for the control of dynamic quadrature boosters (DQBs) installed distributively in a large-scale power system to enhance the power system stability. In this strategy, a reinforcement learning technique is employed to search for optimal parameters of the fuzzy logic controllers according to a given performance index, to control the DQBs in a coordinated fashion. A simulation study is undertaken in a thirteen-machine power system. The simulation results show that the LCFLC can be used as an online control strategy to give coordination of the locally installed DQBs to improve the power system stability
[21] X. Zhou and J. Liang, "Overview of control schemes for TCSC to enhance the stability of power systems," Iee Proceedings-Generation Transmission and Distribution, vol. 146, no. 2, pp. 125-130, Mar.1999.
Abstract: Many studies on thyristor-controlled series compensation (TCSC) have been reported; transient stability enhancement and power oscillation damping are two important functions of TCSC, In the paper, control schemes for TCSC on these two functions are classified and reviewed. The relevant issues are also analysed and discussed. More suitable and advanced control schemes are expected to increase the transient and dynamic stability of power systems
Abstract: Many studies on thyristor-controlled series compensation (TCSC) have been reported; transient stability enhancement and power oscillation damping are two important functions of TCSC, In the paper, control schemes for TCSC on these two functions are classified and reviewed. The relevant issues are also analysed and discussed. More suitable and advanced control schemes are expected to increase the transient and dynamic stability of power systems
[22] Y. Y. Hsu and T. S. Luor, "Damping of power system oscillations using adaptive thyristor-controlled series compensators tuned by artificial neural networks," Iee Proceedings-Generation Transmission and Distribution, vol. 146, no. 2, pp. 137-142, Mar.1999.
Abstract: A proportional-integral (PI) controller is designed for thyristor-controlled series compensators (TCSCs) to improve the damping for power system oscillations. To maintain a good damping characteristic over a wide range of operating conditions, the gains of the PI controller are adapted in real time, based on online measured transmission line loadings (real and reactive power flows). To speed up the online gain adaptation process, an artificial neural network which is capable of performing complicated computations in a parallel, distributed manner is designed. A major feature of the proposed adaptive PI controller is that only physically measurable variables (real and reactive power flows over the transmission line) are employed as inputs to the adaptive controller. To demonstrate the effectiveness of the proposed adaptive TCSC controller, computer simulations are performed on a power system under disturbance conditions. It is concluded from the simulation results that the proposed adaptive TCSC controller can yield satisfactory dynamic responses over a wide range of operating conditions. Low-frequency oscillations in the frequency range 0.3-2Hz have been effectively damped by the proposed compensators
Abstract: A proportional-integral (PI) controller is designed for thyristor-controlled series compensators (TCSCs) to improve the damping for power system oscillations. To maintain a good damping characteristic over a wide range of operating conditions, the gains of the PI controller are adapted in real time, based on online measured transmission line loadings (real and reactive power flows). To speed up the online gain adaptation process, an artificial neural network which is capable of performing complicated computations in a parallel, distributed manner is designed. A major feature of the proposed adaptive PI controller is that only physically measurable variables (real and reactive power flows over the transmission line) are employed as inputs to the adaptive controller. To demonstrate the effectiveness of the proposed adaptive TCSC controller, computer simulations are performed on a power system under disturbance conditions. It is concluded from the simulation results that the proposed adaptive TCSC controller can yield satisfactory dynamic responses over a wide range of operating conditions. Low-frequency oscillations in the frequency range 0.3-2Hz have been effectively damped by the proposed compensators
[23] S. Limyingcharoen, U. D. Annakkage, and N. C. Pahalawaththa, "Fuzzy logic based unified power flow controllers for transient stability improvement," Iee Proceedings-Generation Transmission and Distribution, vol. 145, no. 3, pp. 225-232, May1998.
Abstract: A fuzzy logic approach is applied to coordinate three control inputs: in-phase voltage control, quadrature voltage control, and shunt compensation, of a unified power flow controller to improve the transient stability of a power system. The fuzzy rules for the controller are created based on a bang-bang control strategy whose objectives are minimising the first swing, damping the oscillations at an optimum rate, and maximising the transient stability margin. The proposed controller also incorporates a technique of reducing the chattering of generator output which naturally results from the application of bang-bang control. Simulation results show that the fuzzy logic based controller provides satisfactory performance, meeting the design objectives. The results also show the robustness of the controller
Abstract: A fuzzy logic approach is applied to coordinate three control inputs: in-phase voltage control, quadrature voltage control, and shunt compensation, of a unified power flow controller to improve the transient stability of a power system. The fuzzy rules for the controller are created based on a bang-bang control strategy whose objectives are minimising the first swing, damping the oscillations at an optimum rate, and maximising the transient stability margin. The proposed controller also incorporates a technique of reducing the chattering of generator output which naturally results from the application of bang-bang control. Simulation results show that the fuzzy logic based controller provides satisfactory performance, meeting the design objectives. The results also show the robustness of the controller
[24] T. T. Lie, G. B. Shrestha, and A. Ghosh, "Design and Application of A Fuzzy-Logic Control Scheme for Transient Stability Enhancement in Power-Systems," Electric Power Systems Research, vol. 33, no. 1, pp. 17-23, Apr.1995.
Abstract: A fuzzy logic controller is designed to implement variable series capacitor compensation in the transmission network of interconnected power systems. This compensation scheme is one of the most widely accepted as a solution to limitations created by overstretched generation and transmission systems. This is one facet of flexible AC transmission systems (FACTS) employed to enhance the stability of the system. The effectiveness of the fuzzy logic controller to properly control such a variable series capacitor under different types of system disturbance is demonstrated through simulation studies on a single-machine infinite-bus system. The results of these simulation studies show that the controller can contribute tremendously to the enhancement of power system transient stability during such disturbances. Considerable increase in power throughput and significant improvement in the damping of the electromechanical oscillations are achieved by implementing this device in the transmission system
Abstract: A fuzzy logic controller is designed to implement variable series capacitor compensation in the transmission network of interconnected power systems. This compensation scheme is one of the most widely accepted as a solution to limitations created by overstretched generation and transmission systems. This is one facet of flexible AC transmission systems (FACTS) employed to enhance the stability of the system. The effectiveness of the fuzzy logic controller to properly control such a variable series capacitor under different types of system disturbance is demonstrated through simulation studies on a single-machine infinite-bus system. The results of these simulation studies show that the controller can contribute tremendously to the enhancement of power system transient stability during such disturbances. Considerable increase in power throughput and significant improvement in the damping of the electromechanical oscillations are achieved by implementing this device in the transmission system
[25] P. K. Dash, S. Elangovan, and A. C. Liew, "Design of Nonlinear Expert Supervisory Controllers for Power-System Stabilization," Electric Power Systems Research, vol. 33, no. 1, pp. 25-32, Apr.1995.
Abstract: This paper presents the design of a new nonlinear expert controller for single-machine infinite-bus and multimachine power systems. The controller uses the concepts of fuzzy linguistic control for normal and abnormal operating conditions of the power system. A nonlinear supervisory controller based on variable-structure system theory is designed to augment the linguistic fuzzy controller for severe transient disturbances when there is a possibility of the stability being lost. This robust nonlinear expert controller is applied to a single-machine infinite-bus system and some other selected machines in a multimachine power system subject to a variety of transient disturbances. The damping performance of this controller is found to be significantly better than the traditional fuzzy and conventional power system stabilizers
Abstract: This paper presents the design of a new nonlinear expert controller for single-machine infinite-bus and multimachine power systems. The controller uses the concepts of fuzzy linguistic control for normal and abnormal operating conditions of the power system. A nonlinear supervisory controller based on variable-structure system theory is designed to augment the linguistic fuzzy controller for severe transient disturbances when there is a possibility of the stability being lost. This robust nonlinear expert controller is applied to a single-machine infinite-bus system and some other selected machines in a multimachine power system subject to a variety of transient disturbances. The damping performance of this controller is found to be significantly better than the traditional fuzzy and conventional power system stabilizers
[26] H. C. Chang and M. H. Wang, "Neural-Network-Based Self-Organizing Fuzzy Controller for Transient Stability of Multimachine Power-Systems," Ieee Transactions on Energy Conversion, vol. 10, no. 2, pp. 339-347, June1995.
Abstract: An efficient self-organizing neural fuzzy controller (SONFC) is designed to improve the transient stability of multimachine power systems. First, an artificial neural network (ANN)-based model is introduced for fuzzy logic control. The characteristic rules and their membership functions of fuzzy systems are represented as the processing nodes in the ANN model, With the excellent learning capability inherent in the ANN, the traditional heuristic fuzzy control rules and input/output fuzzy membership functions can be optimally tuned from training examples by the backpropagation learning algorithm. Considerable rule-matching times of the inference engine in the traditional fuzzy system can be saved. To illustrate the performance and usefulness of the SONFC, comparative studies with a bang-bang controller are performed on the 34-generator Taipower system with rather encouraging results
Abstract: An efficient self-organizing neural fuzzy controller (SONFC) is designed to improve the transient stability of multimachine power systems. First, an artificial neural network (ANN)-based model is introduced for fuzzy logic control. The characteristic rules and their membership functions of fuzzy systems are represented as the processing nodes in the ANN model, With the excellent learning capability inherent in the ANN, the traditional heuristic fuzzy control rules and input/output fuzzy membership functions can be optimally tuned from training examples by the backpropagation learning algorithm. Considerable rule-matching times of the inference engine in the traditional fuzzy system can be saved. To illustrate the performance and usefulness of the SONFC, comparative studies with a bang-bang controller are performed on the 34-generator Taipower system with rather encouraging results
[27] P. K. Dash and A. C. Liew, "Anticipatory Fuzzy Control of Power-Systems," Iee Proceedings-Generation Transmission and Distribution, vol. 142, no. 2, pp. 211-218, Mar.1995.
Abstract: The paper presents an anticipatory fuzzy control to improve the stability of electric power systems. This differs from the traditional fuzzy control in that, once the fuzzy-control rules have been used to generate a control value, a predictive routine built into the controller is called for anticipating its effect on the system output and hence updating the rule base or input-output membership functions in the event of unsatisfactory performance. The effectiveness of the anticipatory and traditional PI fuzzy controllers is demonstrated by simulation studies on a single-machine infinite-bus and multimachine power system subjected to a variety of transient disturbances for different operating conditions. The anticipatory fuzzy control, however, requires a neural-network prediction routine using modified-Kalman-filter-based fast-learning algorithm
Abstract: The paper presents an anticipatory fuzzy control to improve the stability of electric power systems. This differs from the traditional fuzzy control in that, once the fuzzy-control rules have been used to generate a control value, a predictive routine built into the controller is called for anticipating its effect on the system output and hence updating the rule base or input-output membership functions in the event of unsatisfactory performance. The effectiveness of the anticipatory and traditional PI fuzzy controllers is demonstrated by simulation studies on a single-machine infinite-bus and multimachine power system subjected to a variety of transient disturbances for different operating conditions. The anticipatory fuzzy control, however, requires a neural-network prediction routine using modified-Kalman-filter-based fast-learning algorithm
[28] P. K. Dash, A. C. Liew, and A. Routray, "High-Performance Controllers for Hvdc Transmission Links," Iee Proceedings-Generation Transmission and Distribution, vol. 141, no. 5, pp. 422-428, Sept.1994.
Abstract: The paper presents the design of a very simple fuzzy logic controller for HVDC transmission links for fast stabilisation of transient oscillations. The performance of this controller is compared with variable structure and adaptive controllers for a variety of short circuits and system operational changes. Unlike both adaptive and VSS controllers which require at least functionally an accurate model of the system dynamics, the fuzzy controller does not require a mathematical model of the system to estimate the control input under disturbance conditions. The transient simulation studies presented reveal the superior performance of the simple fuzzy controller in damping out system transients
Abstract: The paper presents the design of a very simple fuzzy logic controller for HVDC transmission links for fast stabilisation of transient oscillations. The performance of this controller is compared with variable structure and adaptive controllers for a variety of short circuits and system operational changes. Unlike both adaptive and VSS controllers which require at least functionally an accurate model of the system dynamics, the fuzzy controller does not require a mathematical model of the system to estimate the control input under disturbance conditions. The transient simulation studies presented reveal the superior performance of the simple fuzzy controller in damping out system transients
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