This document summarizes a research paper about using an adaptive neuro-fuzzy controller for a unified power flow controller (UPFC) to damp low frequency oscillations (LFO) in a power system.
The key points are:
1. LFO can occur in power systems due to a lack of damping torque. Traditionally, power system stabilizers were used but FACTS devices like UPFC can also control power flow and provide damping.
2. An adaptive neuro-fuzzy controller is designed for the UPFC to damp LFO. The controller has 2 inputs of deviation in rotor angle and deviation in frequency. Simulation results show it provides good damping performance.
3. The performance of the neuro-fuzzy
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
This paper presents a grid-connected photovoltaic (PV) interface for delivering both active and reactive powers. The PV interface employs H-bridge topology DC-DC converter and inverter with analog control technology. The power flow is controlled solely by the adjustable DC output voltage of the DC to DC converter. In order to evaluate the PV interface system’s performances, it is tested by delivering power to the grid with low pawer factor. The experimental results show that at 300W active load, the inverter could deliver the reactive power of 400VAR. The PV interface could also produce very low harmonic voltage and current distorsions. The laboratory measurements show that the total harmonic distortions of inverter output voltage and current are 0.46% and 0.05%, respectively.
Design and Analysis of Adaptive Neural Controller for Voltage Source Converte...IDES Editor
Usually a STATCOM is installed to support power
system networks that have a poor power factor and often poor
voltage regulation. It is based on a power electronics voltagesource
converter. Various PWM techniques make selective
harmonic elimination possible, which effectively control the
harmonic content of voltage source converters. The distribution
systems have to supply unbalanced nonlinear loads transferring
oscillations to the DC-side of the converter in a realistic
operating condition. Thus, additional harmonics are modulated
through the STATCOM at the point of common coupling
(PCC). This requires more attention when switching angles are
calculated offline using the optimal PWM technique. This
paper, therefore, presents the artificial neural network model
for defining the switching criterion of the VSC for the
STATCOM in order to reduce the total harmonic distortion
(THD) of the injected line current at the PCC. The model takes
into the account the dc capacitor effect, effects of other possible
varying parameters such as voltage unbalance as well as
network harmonics. A reference is developed for offline
prediction and then implemented with the help of back
propagation technique.
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
Low frequency ac transmission for power systems by Aamir SaleemAamir Saleem
Voltage instability is one of the major issue in
HVAC power network operating at 50 Hz frequency due to
limited power transfer capability and distance limit. The stable
operation of power system must be kept within limits to
increase the efficiency of power transmission system. In this
research Low Frequency AC (LFAC) transmission system has
been proposed as a new power transmission technology to
reduce the losses of transmission network and controlling the
reactive power using Flexible AC transmission device. A
LFAC Transmission lines operates at 16.7Hz frequency for
transmission of power from source to load and use two
Frequency converters at source and load side. The normal
operation of power system depends on the reactive power
flowing through the power transmission lines, which can be
adjusted by a flexible AC transmission device; Static
synchronous compensator. LFAC transmission lines with
STATCOM controller improve the Power system voltage
stability under various disturbances and enhance the power
transmission capability as compare to HVAC transmission.
The simulations are done in Matlab Simulink 2017a .The
Output of Matlab Simulink model shows that voltage will
become Stable and reactive power is compensated for best
performance for power system.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
This paper presents a grid-connected photovoltaic (PV) interface for delivering both active and reactive powers. The PV interface employs H-bridge topology DC-DC converter and inverter with analog control technology. The power flow is controlled solely by the adjustable DC output voltage of the DC to DC converter. In order to evaluate the PV interface system’s performances, it is tested by delivering power to the grid with low pawer factor. The experimental results show that at 300W active load, the inverter could deliver the reactive power of 400VAR. The PV interface could also produce very low harmonic voltage and current distorsions. The laboratory measurements show that the total harmonic distortions of inverter output voltage and current are 0.46% and 0.05%, respectively.
Design and Analysis of Adaptive Neural Controller for Voltage Source Converte...IDES Editor
Usually a STATCOM is installed to support power
system networks that have a poor power factor and often poor
voltage regulation. It is based on a power electronics voltagesource
converter. Various PWM techniques make selective
harmonic elimination possible, which effectively control the
harmonic content of voltage source converters. The distribution
systems have to supply unbalanced nonlinear loads transferring
oscillations to the DC-side of the converter in a realistic
operating condition. Thus, additional harmonics are modulated
through the STATCOM at the point of common coupling
(PCC). This requires more attention when switching angles are
calculated offline using the optimal PWM technique. This
paper, therefore, presents the artificial neural network model
for defining the switching criterion of the VSC for the
STATCOM in order to reduce the total harmonic distortion
(THD) of the injected line current at the PCC. The model takes
into the account the dc capacitor effect, effects of other possible
varying parameters such as voltage unbalance as well as
network harmonics. A reference is developed for offline
prediction and then implemented with the help of back
propagation technique.
Close Loop Control of Induction Motor Using Z-Source InverterIJSRD
In this paper a new closed loop control of induction motor fed by a Z – source inverter based on the vector control or field oriented control strategy is presented. Induction motor is supplied by Z – source inverter, in the Z – source inverter the term Z denotes impedance which means a combination of L & C element which are cross connected. The Z-source inverter consists of a unique impedance network (or circuit) to couple the inverter main circuit to the power supply, hence providing great features that cannot be observed in the conventional voltage-source inverter and current-source inverters in which capacitor and inductor are used, respectively.In the field oriented control method or vector control method speed of the induction motor, torque & 3 phase stator current is given to the field oriented controller and gate pulses for the inverter is generated to obtain the desired operation of the induction motor.
Low frequency ac transmission for power systems by Aamir SaleemAamir Saleem
Voltage instability is one of the major issue in
HVAC power network operating at 50 Hz frequency due to
limited power transfer capability and distance limit. The stable
operation of power system must be kept within limits to
increase the efficiency of power transmission system. In this
research Low Frequency AC (LFAC) transmission system has
been proposed as a new power transmission technology to
reduce the losses of transmission network and controlling the
reactive power using Flexible AC transmission device. A
LFAC Transmission lines operates at 16.7Hz frequency for
transmission of power from source to load and use two
Frequency converters at source and load side. The normal
operation of power system depends on the reactive power
flowing through the power transmission lines, which can be
adjusted by a flexible AC transmission device; Static
synchronous compensator. LFAC transmission lines with
STATCOM controller improve the Power system voltage
stability under various disturbances and enhance the power
transmission capability as compare to HVAC transmission.
The simulations are done in Matlab Simulink 2017a .The
Output of Matlab Simulink model shows that voltage will
become Stable and reactive power is compensated for best
performance for power system.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Increase productivity and absorption of reactive power for power station with...IJITCA Journal
In this article, a new method of reactive power compensation for Synchronous generator power stations by
using static reactive power compensator provided. The advantages of this methodis used for control
voltage transmission is removing capacitors and reactors power station that their changing great voltage
and current transients in the power system. Also using of this compensator will improve automatic voltage
regulator function (AVR).
This paper presents a droop control technique for equal power sharing in islanded microgrid. In this study, the proposed controller is based on the frequency droop method, is applied to a robust droop controller in parallel connected inverters. The previous robust droop controller deals with voltage droop method. A modification has been formed against this controller by adding a fuzzy logic controller with the frequency droop method. The only sharing error which is concentrated in this paper is the error in sharing the rated frequency among the inverters. By adapting fuzzy in the robust droop, it tries to eliminate the frequency error, hence that the frequency reference of the inverters keeps maintain at 50Hz. A derivation of generalized models of a single-phase parallel-connected inverter system is shown. The simulation results show that the proposed controller with FLC is able to improve the stability of frequency reference and the performance of power sharing between the inverters under the inductive line impedance.
The use of conventional devices as control mechanism for system voltage profile enhancement
and loss reduction is still predominantly prevalent in most third world nations and Nigeria is never an
exemption. This study seeks to compare efficiency of Load Tap-Changing Transformer and Shunt Capacitors
using system voltage profile enhancement and real power loss minimization as performance matrix on
Nigerian 330kV, 24-Bus grid system as a test case. In this work, the Newton Raphson iterative algorithm was
adopted due to its superior features over other iterative techniques. Load flow analysis was performed on the
test case with and without incorporation of LTCT and Shunt Capacitors, the result of the analysis shows that
with shunt capacitors injection at the weak buses identified, the algorithm converged in 5 iterations but with
LTC transformer convergence was achieved in 4 iterations. Also, the total system losses with shunt capacitor
injection was found to be 82.2826MW which is about 4.1% reduction while with LTC transformer, the total
system losses reduced appreciably to 81.9865MW which is about 4.8% reduction. Incorporation of LTCT
gives a better improvement on system voltage profile compared with the improvement observed with shunt
capacitor injection at the defective buses identified.
This paper describes the steady-state response and control of power in transmission line equipped with
FACTS devices. Detailed simulations are carried out on two -machine systems to illustrate the control
features of these devices and their influence to increase power transfer capability and improve
system reliability. The DPFC is derived from the unified power-flow controller (UPFC) and DPFC
has the same control capability as the UPFC. The DPFC can be considered as a UPFC with an eliminated
common dc link. The active power exchange between the shunt and series converters, which is through the
common dc link in the UPFC, is now through the transmission lines at the third -harmonic frequency.
The interaction between the DPFC, the network and the machines are analyzed.
Development and implementation of two-stage boost converter for single-phase ...IJECEIAES
This paper offers a two-stage boost converter for a single-phase inverter without transformer for PV systems. Each stage of the converter is separately controlled by a pulse width modulated signal. A Simulink model of the converter using efficient voltage control topology is developed. The proposed circuit performance characteristics are explained and the obtained simulation results are confirmed through the applied experiments. Moreover, this paper has examined the control circuit of a single-phase inverter that delivers a pure sine wave with an output voltage that has the identical value and frequency as a grid voltage. A microcontroller supported an innovative technology is utilized to come up with a sine wave with fewer harmonics, much less price and an easier outline. A sinusoidal pulse width modulation (SPWM) technique is used by a microcontroller. The developed inverter integrated with the twostage boost converter has improved the output waveform quality and controlled the dead time as it decreased to 63 µs compared to 180 µs in conventional methods. The system design is reproduced in Proteus and PSIM Software to analyze its operation principle that is confirmed practically.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
POWER QUALITY IMPROVEMENT IN TRANSMISSION LINE USING DPFCvivatechijri
This project presents the MATLAB Simulation model of the Distributed Power Flow Controller in Transmission line. This work will be a new component with the flexible ac transmission system, called as distributed power flow controller (DPFC). The DPFC will be derived from the unified power flow controller system (UPFC). The DPFC can be considered as a UPFC with a common dc link which is eliminated. The active power exchange between the series and shunt converters, through the common dc link in the UPFC, is now through the transmission lines at the third-harmonic frequency. DPFC has the same control ability as the UPFC, which adjusts line impedance, bus voltages, and the transmission lines.
Static Sustenance of Power System Stability Using FLC Based UPFC in SMIB Powe...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Enhancement of Power System Dynamics Using a Novel Series Compensation SchemeIJMER
Phase imbalanced capacitive compensation is a “hybrid” series compensation scheme, where the
series capacitive compensation in one phase is created using a single-phase TCSC in series with a fixed capacitor
(Cc), and the other two phases are compensated by fixed series capacitors (C). The TCSC control is initially set
such that its equivalent compensations at the power frequency combined with the fixed capacitor yield a
resultant compensation equal to the other two phases. Thus, the phase balance is maintained at the power
frequency while at any other frequency, a phase imbalance is created. The effectiveness of the scheme in damping
power system oscillations for various network conditions, namely different system faults and tie-line power flows is
evaluated using the MATLAB/SIMULINK Software
APPLICATION OF STATCOM to IMPROVED DYNAMIC PERFORMANCE OF POWER SYSTEMijsrd.com
Application of FACTS controller called Static Synchronous Compensator STATCOM to improve the performance of power grid with Wind Farms is investigated .The essential feature of the STATCOM is that it has the ability to absorb or inject fastly the reactive power with power grid . Therefore the voltage regulation of the power grid with STATCOM FACTS device is achieved. Moreover restoring the stability of the power system having wind farm after occurring severe disturbance such as faults or wind farm mechanical power variation is obtained with STATCOM controller . The dynamic model of the power system having wind farm controlled by proposed STATCOM is developed . To validate the powerful of the STATCOM FACTS controller, the studied power system is simulated and subjected to different severe disturbances. The results prove the effectiveness of the proposed STATCOM controller in terms of fast damping the power system oscillations and restoring the power system stability.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Increase productivity and absorption of reactive power for power station with...IJITCA Journal
In this article, a new method of reactive power compensation for Synchronous generator power stations by
using static reactive power compensator provided. The advantages of this methodis used for control
voltage transmission is removing capacitors and reactors power station that their changing great voltage
and current transients in the power system. Also using of this compensator will improve automatic voltage
regulator function (AVR).
This paper presents a droop control technique for equal power sharing in islanded microgrid. In this study, the proposed controller is based on the frequency droop method, is applied to a robust droop controller in parallel connected inverters. The previous robust droop controller deals with voltage droop method. A modification has been formed against this controller by adding a fuzzy logic controller with the frequency droop method. The only sharing error which is concentrated in this paper is the error in sharing the rated frequency among the inverters. By adapting fuzzy in the robust droop, it tries to eliminate the frequency error, hence that the frequency reference of the inverters keeps maintain at 50Hz. A derivation of generalized models of a single-phase parallel-connected inverter system is shown. The simulation results show that the proposed controller with FLC is able to improve the stability of frequency reference and the performance of power sharing between the inverters under the inductive line impedance.
The use of conventional devices as control mechanism for system voltage profile enhancement
and loss reduction is still predominantly prevalent in most third world nations and Nigeria is never an
exemption. This study seeks to compare efficiency of Load Tap-Changing Transformer and Shunt Capacitors
using system voltage profile enhancement and real power loss minimization as performance matrix on
Nigerian 330kV, 24-Bus grid system as a test case. In this work, the Newton Raphson iterative algorithm was
adopted due to its superior features over other iterative techniques. Load flow analysis was performed on the
test case with and without incorporation of LTCT and Shunt Capacitors, the result of the analysis shows that
with shunt capacitors injection at the weak buses identified, the algorithm converged in 5 iterations but with
LTC transformer convergence was achieved in 4 iterations. Also, the total system losses with shunt capacitor
injection was found to be 82.2826MW which is about 4.1% reduction while with LTC transformer, the total
system losses reduced appreciably to 81.9865MW which is about 4.8% reduction. Incorporation of LTCT
gives a better improvement on system voltage profile compared with the improvement observed with shunt
capacitor injection at the defective buses identified.
This paper describes the steady-state response and control of power in transmission line equipped with
FACTS devices. Detailed simulations are carried out on two -machine systems to illustrate the control
features of these devices and their influence to increase power transfer capability and improve
system reliability. The DPFC is derived from the unified power-flow controller (UPFC) and DPFC
has the same control capability as the UPFC. The DPFC can be considered as a UPFC with an eliminated
common dc link. The active power exchange between the shunt and series converters, which is through the
common dc link in the UPFC, is now through the transmission lines at the third -harmonic frequency.
The interaction between the DPFC, the network and the machines are analyzed.
Development and implementation of two-stage boost converter for single-phase ...IJECEIAES
This paper offers a two-stage boost converter for a single-phase inverter without transformer for PV systems. Each stage of the converter is separately controlled by a pulse width modulated signal. A Simulink model of the converter using efficient voltage control topology is developed. The proposed circuit performance characteristics are explained and the obtained simulation results are confirmed through the applied experiments. Moreover, this paper has examined the control circuit of a single-phase inverter that delivers a pure sine wave with an output voltage that has the identical value and frequency as a grid voltage. A microcontroller supported an innovative technology is utilized to come up with a sine wave with fewer harmonics, much less price and an easier outline. A sinusoidal pulse width modulation (SPWM) technique is used by a microcontroller. The developed inverter integrated with the twostage boost converter has improved the output waveform quality and controlled the dead time as it decreased to 63 µs compared to 180 µs in conventional methods. The system design is reproduced in Proteus and PSIM Software to analyze its operation principle that is confirmed practically.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
POWER QUALITY IMPROVEMENT IN TRANSMISSION LINE USING DPFCvivatechijri
This project presents the MATLAB Simulation model of the Distributed Power Flow Controller in Transmission line. This work will be a new component with the flexible ac transmission system, called as distributed power flow controller (DPFC). The DPFC will be derived from the unified power flow controller system (UPFC). The DPFC can be considered as a UPFC with a common dc link which is eliminated. The active power exchange between the series and shunt converters, through the common dc link in the UPFC, is now through the transmission lines at the third-harmonic frequency. DPFC has the same control ability as the UPFC, which adjusts line impedance, bus voltages, and the transmission lines.
Static Sustenance of Power System Stability Using FLC Based UPFC in SMIB Powe...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
Enhancement of Power System Dynamics Using a Novel Series Compensation SchemeIJMER
Phase imbalanced capacitive compensation is a “hybrid” series compensation scheme, where the
series capacitive compensation in one phase is created using a single-phase TCSC in series with a fixed capacitor
(Cc), and the other two phases are compensated by fixed series capacitors (C). The TCSC control is initially set
such that its equivalent compensations at the power frequency combined with the fixed capacitor yield a
resultant compensation equal to the other two phases. Thus, the phase balance is maintained at the power
frequency while at any other frequency, a phase imbalance is created. The effectiveness of the scheme in damping
power system oscillations for various network conditions, namely different system faults and tie-line power flows is
evaluated using the MATLAB/SIMULINK Software
APPLICATION OF STATCOM to IMPROVED DYNAMIC PERFORMANCE OF POWER SYSTEMijsrd.com
Application of FACTS controller called Static Synchronous Compensator STATCOM to improve the performance of power grid with Wind Farms is investigated .The essential feature of the STATCOM is that it has the ability to absorb or inject fastly the reactive power with power grid . Therefore the voltage regulation of the power grid with STATCOM FACTS device is achieved. Moreover restoring the stability of the power system having wind farm after occurring severe disturbance such as faults or wind farm mechanical power variation is obtained with STATCOM controller . The dynamic model of the power system having wind farm controlled by proposed STATCOM is developed . To validate the powerful of the STATCOM FACTS controller, the studied power system is simulated and subjected to different severe disturbances. The results prove the effectiveness of the proposed STATCOM controller in terms of fast damping the power system oscillations and restoring the power system stability.
Static Synchronous Series Compensator (SSSC) with Superconducting Magnetic En...IDES Editor
Static Synchronous Series Compensator (SSSC) has
been designed with Superconducting Magnetic Energy Storage
(SMES) system. A closed loop control scheme has been
proposed with PI controller and real and reactive powers are
taken as references. A 48 pulse voltage source inverter is
designed for the SSSC. Control scheme for the chopper circuit
of SMES coil is also designed. A three area system is taken as
the test system and the operation of SSSC with SMES is
analysed for various transient disturbances. Test results under
different disturbances and operating conditions show the
proposed SSSC with SMES is effective in damping out the
power system oscillations.
STATCOM for Improved Dynamic Performance of Wind Farms in Power Grid IJMER
Application of FACTS controller called Static Synchronous Compensator STATCOM to
improve the performance of power grid with Wind Farms is investigated .The essential feature of the
STATCOM is that it has the ability to absorb or inject the reactive power with power grid. Therefore,
the voltage regulation of the power grid with STATCOM FACTS device is achieved. Moreover restoring
the stability of the power system having wind farm after occurring severe disturbance such as faults or
wind farm mechanical power variation is obtained with STATCOM controller. The dynamic model of
the power system having wind farm controlled by proposed STATCOM is developed. To validate the
powerful of the STATCOM FACTS controller, the studied power system is simulated and subjected to
different severe disturbances. The results prove the effectiveness of the proposed STATCOM controller
in terms of fast damping the power system oscillations and restoring the power system stability.
The determination of this paper is to introduce two new spaces , namely 𝑆𝑔
∗
-compact and 𝑆𝑔
∗
-
connected spaces. Additionally some properties of these spaces are investigated.
Mathematics Subject Classification: 54A05
Power Flow Control In A Transmission Line Using Unified Power Flow ControllerIJMER
This paper concentrates on FACT device UPFC which is used for powerflow control in the
transmission side. With the growing demand of electricity, it is not possible to erect new lines to face the
situation. Flexible AC Transmission System (FACTS) makes use of the thyristor controlled devices and optimally
utilizes the existing transmission network. One of such device is Unified Power Flow Controller (UPFC) on
which the emphasis is given in this present work. Real, reactive power, and voltage balance of the unified
power-flow control (UPFC) system is analyzed. A novel coordination controller is proposed for the UPFC.
The basic control method is such that the shunt converter controls the transmission line reactive power
flow and the dc-link voltage. The series converter controls the real power flow in the transmission line and
the UPFC bus voltages. Experimental works have been conducted to verify the effectiveness of the
UPFC in power flow control in the transmission line. The simulation model was done in
MATLAB/SIMULINK platform.
A New Approach to Powerflow Management in Transmission System Using Interline...IJERA Editor
In this paper a new approach to power flow management in transmission system using interline Power Flow
Controller (IPFC) is proposed and model for IPFC is developed and simulate by MATLAB software. Interline
Power Flow Controller is a versatile device can be used to control power flows of a multi-line system or subnetworks
An Interline Power Flow Controller (IPFC) is a converter based FACTS controller for series
compensation with capability of controlling power flow among multi-lines within the same corridor of the
transmission line. It consists of two or more Voltage Source Converters (VSCs) with a common dc-link. Real
power can be transferred via the common dc-link between the VSCs and each VSC is capable of exchanging
reactive power with its own transmission system
International Journal of Engineering Research and Development is an international premier peer reviewed open access engineering and technology journal promoting the discovery, innovation, advancement and dissemination of basic and transitional knowledge in engineering, technology and related disciplines.
International Journal of Engineering and Science Invention (IJESI) inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
ANFIS Based UPQC for Power Quality ImprovementIJMTST Journal
Analysis of a three-phase three wire Unified Power Quality Conditioner (UPQC) controlled with Adaptive Neuro Fuzzy Inference System based controller is presented in this project. UPQC is a custom power device which is integrated by series and shunt active power filters (APF) sharing a common dc bus capacitor. The shunt and series APFs are realized with the help of three – phase, three leg voltage source converters that are sharing a common DC capacitor. The fundamental voltages, currents are extracted by modified synchronous reference frame technique; switching pulses for both the filters are generated by conventional hysteresis based controller. The capacitance voltage is balanced by ANFIS based controller. Performance of the ANFIS based control algorithm of shunt active filter with series active filter is evaluated in terms of eliminating the power quality problems in a three phase, three-wire distribution system with non-linear and unbalanced load conditions. Adaptive neuro fuzzy logic control is used for dc capacitance balancing. System taken for test and the control algorithm are implemented with the help of Sim power systems and ANFIS editor of MATLAB / SIMULINK.
Performance and Analysis of Reactive Power Compensation by Unified Power Flow...ijeei-iaes
The Unified Power Flow Controller (UPFC) is the most versatile of the FACTS controllers envisaged so far. The main function of the UPFC is to control the flow of real and reactive power by injection of a voltage in series with the transmission line. Both the magnitude and the phase angle of the voltage can be varied independently. Real and Reactive power flow control can allow for power flow in prescribed routes, loading of transmission lines close to their thermal limits and can be utilized for improving transient and small signal stability of the power system. In this paper UPFC is incorporated in a SMIB (Single Machine Infinite Bus) system and the response of SMIB system has been recorded with and without UPFC, thereafter the comparison of both the output has been done. When no UPFC is installed, real and reactive power through the transmission line cannot be controlled. This paper presents control and performance of UPFC intended for installation on that transmission line to control power flow. Installing the UPFC makes it possible to control amount of active power flowing through the line. Simulations are carried out using MATLAB software to validate the performance of the UPFC.
Simulation Of Interline Power Flow Controller in Power Transmission Systemijsrd.com
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solution is the use of FACTS devices especially the use of UPFC. Unified Power Flow Controller (UPFC)
is the most widely used FACTS device to control the power flow and to optimize the system stability in the
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impedance, voltage magnitude and phase angle. This controller offers advantages in terms of static and
dynamic operation of the power system. The UPFC with its various modes of operation is understood.
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International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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During Damping of Low Frequency Oscillations in Power Systems with Fuzzy UPFC Controller
1. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4215-4219 ISSN: 2249-6645
During Damping of Low Frequency Oscillations in Power Systems with
Fuzzy UPFC Controller
M.Bala Ankanna, 1 K.Harinath Reddy, 2
M.Tech (EPE), Department of EEE, AITS, Rajampet, A.P,
Assistant Professor, Department of EEE, AITS, Rajampet, A.P,
Abstract: Low Frequency Oscillations (LFO) occur in components. Devices for high power levels have been made
power systems because of lack of the damping torque in available in converters for high and even highest voltage
order to dominance to power system disturbances as an levels. The growth of the demand for electrical energy leads
example of change in mechanical input power. In the recent to loading the transmission system near their limits. Thus,
past Power System Stabilizer (PSS) was used to damp LFO. the occurrence of the LFO has increased. FACTs
FACTs devices, such as Unified Power Flow Controller Controllers has capability to control network conditions
(UPFC), can control power flow, reduce sub-synchronous quickly and this feature of FACTs can be used to improve
resonance and increase transient stability. So UPFC may power system stability. The UPFC is a FACTS device that
be used to damp LFO instead of PSS. UPFC damps LFO can be used to the LFO. The primarily use of UPFC is to
through direct control of voltage and power. A control the power flow in power systems. The UPFC
comprehensive and systematic approach for mathematical consists of two voltage source converters (VSC) each of
modelling of UPFC for steady-state and small signal them has two control parameters namely me, δe ,mb and δb
(linearize) dynamic studies has been proposed. The other [3]. The UPFC used for power flow control, enhancement
modified linearize Heffron-Philips model of a power system of transient stability, mitigation of system oscillations and
installed with UPFC is presented. For systems which are voltage regulation [3]. A comprehensive and systematic
without power system stabilizer (PSS), excellent damping approach for mathematical modelling of UPFC for steady-
can be achieved via proper controller design for UPFC state and small signal (linearized) dynamic studies has been
parameters. By designing a suitable UPFC controller, an proposed in [4-7]. The other modified linearized Heffron-
effective damping can be achieved. In this research the Philips model of a power system installed with UPFC is
linearize model of synchronous machine (Heffron-Philips) presented in [8] and [9]. For systems which are without
connected to infinite bus (Single Machine-Infinite Bus: power system stabilizer (PSS), excellent damping can be
SMIB) with UPFC is used and also in order to damp LFO, achieved via proper controller design for UPFC parameters.
adaptive neuro-fuzzy controller for UPFC is designed and By designing a suitable UPFC controller, an effective
simulated. Simulation is performed for various types of damping can be achieved. It is usual that Heffron-Philips
loads and for different disturbances. Simulation results model is used in power system to study small signal
show good performance of neuro-fuzzy controller in stability. This model has been used for many years
damping LFO. providing reliable results [10]. In recent years, the study of
UPFC control methods has attracted attentions so that
different control approaches are presented for UPFC control
Keywords: Neuro-Fuzzy Controller, Low Frequency
such as Fuzzy control [11-14], conventional lead-lag
Oscillations (LFO), Unified Power Flow Controller
control [15], Genetic algorithm approach [16], and Robust
(UPFC), Single Machine-Infinite Bus (SMIB)
control methods [17-19].
In this case study, the class of adaptive networks
I. INTRODUCTION that of the same as fuzzy inference system in terms of
Flexible AC Transmission Systems, called FACTS, performance is used. The controller utilized with the above
got in the recent years a well known term for higher structure is called Adaptive Neuro Fuzzy Inference System
controllability in power systems by means of power or briefly ANFIS [20]. Applying neural networks has many
electronic devices. Several FACTS-devices have been advantages such as the ability of adapting to changes, fault
introduced for various applications worldwide. A number of tolerance capability, recovery capability, High-speed
new types of devices are in the stage of being introduced in processing because of parallel processing and ability to
practice. In most of the applications the controllability is build a DSP chip with VLSI Technology. To show
used to avoid cost intensive or landscape requiring performance of the designed adaptive neuro-fuzzy
extensions of power systems, for instance like upgrades or controller, a conventional lead-lag controller that is
additions of substations and power lines. FACTS-devices designed in [15] is used and the simulation results for the
provide a better adaptation to varying operational power system including these two controllers are compared
conditions and improve the usage of existing installations. with each other.
The basic applications of FACTS-devices are: (i).Power
flow control, (ii) Increase of transmission capability, (iii)
Voltage control, (iv)Reactive power compensation, II. MODEL OF THE POWER SYSTEM
(v)Stability improvement, (vi) Power quality improvement, INCLUDING UPFC
(vii)Power conditioning, (viii)Flicker mitigation, UPFC is one of the famous FACTs devices that is
(ix)Interconnection of renewable and distributed generation used to improve power system stability. Fig.1 shows a
and storages. The development of FACTS-devices has single machine- infinite-bus (SMIB) system with UPFC. It
started with the growing capabilities of power electronic is assumed that the UPFC performance is based on pulse
www.ijmer.com 4215 | Page
2. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4215-4219 ISSN: 2249-6645
width modulation (PWM) converters. In figure 1 me, mb and each inverter can independently generate (or absorb)
δe, δb are the amplitude modulation ratio and phase angle of reactive power at its own ac output terminal.
the reference voltage of each voltage source converter Inverter 2 provides the main function of the UPFC
respectively. These values are the input control signals of by injecting an ac voltage Vpq with controllable magnitude
the UPFC. Vpq (0≤Vpq≤Vpqmax) and phase angle (0≤≤360), at the
power frequency, in series with the line via an insertion
transformer. The injected voltage is considered essentially
as a synchronous voltage source. The transmission line
current flows through this voltage source resulting in real
and reactive power exchange between it and the ac system.
The real power exchanged at the ac terminal (i.e., at the
terminal of insertion transformer) is converted by the
inverter into dc power that appears at the dc link as positive
or negative real power demanded. The reactive power
exchanged at the ac terminal is generated internally by the
Fig.1 A single machine connected to infinite bus with
inverter. The basic function of inverter 1 is to supply or
UPFC
absorb the real power demanded by Inverter 2 at the
common dc link. This dc link power is converted back to ac
As it mentioned previously, a linearized model of the power
and coupled to the transmission line via a shunt-connected
system is used in dynamic studies of power system. In order
transformer. Inverter 1 can also generate or absorb
to consider the effect of UPFC in damping of LFO, the
controllable reactive power, if it is desired, and there by it
dynamic model of the UPFC is employed; In this model the
can provide independent shunt reactive compensation for
resistance and transient of the transformers of the UPFC can
the line.
be ignored. The Linearized state variable equations of the
It is important to note that where as there is a
power system equipped with the UPFC can be represented
closed “direct” path for the real power negotiated by the
as [8].
action of series voltage injection through Inverters 1 and 2
back to the line, the corresponding reactive power
exchanged is supplied or absorbed locally by inverter 2 and
therefore it does not flow through the line. Thus, Inverter 1
can be operated at a unity power factor or be controlled to
have a reactive power exchange with the line independently
of the reactive power exchanged by the Inverter 2. This
means there is no continuous reactive power flow through
UPFC. Operation of the UPFC from the standpoint of
conventional power transmission based on reactive shunt
compensation, series compensation, and phase shifting, the
UPFC can fulfill these functions and thereby meet multiple
Where ΔmE, ΔmB , ΔδE and ΔδB are the deviation of input control objectives by adding the injected voltage Vpq, with
control signals of the UPFC. Also in this study IEEE Type- appropriate amplitude.
ST1A excitation system was used.
III. OPERATING PRINCIPLE OF UPFC
In the presently used practical implementation,
The UPFC consists of two switching converters, which in
the implementations considered are voltage source inverters
using gate turn-off (GTO) thyristor valves, as illustrated in
the Fig 2.1. These back to back converters labeled “Inverter
1 and “Inverter 2” in the figure are operated from a Fig2.Principle configuration of an UPFC
common dc link provided by a dc storage capacitor.
The UPFC consists of a shunt and a series
transformer, which are connected via two voltage source
converters with a common DC-capacitor. The DC-circuit
allows the active power exchange between shunt and series
transformer to control the phase shift of the series voltage.
This setup, as shown in Figure 1.21, provides the full
controllability for voltage and power flow. The series
Fig. Basic circuit arrangement of unified power flow converter needs to be protected with a Thyristor bridge.
controller Due to the high efforts for the Voltage Source Converters
and the protection, an UPFC is getting quite expensive,
This arrangement functions as an ac to ac power which limits the practical applications where the voltage
converter in which the real power can freely flow in either and power flow control is required simultaneously.
direction between the ac terminals of the two inverters and
www.ijmer.com 4216 | Page
3. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4215-4219 ISSN: 2249-6645
IV. CONTROLLER DESIGN combination of linear and nonlinear parameters learning
I. Lead-Lag Controller Design algorithm. Description for learning procedure can be found
As mentioned before, in this study two different in [20]. This network is called adaptive by Jang and it is
controllers have been used to damp LFO. The first one is functionally equivalent to Sugeno type of a fuzzy system. It
conventional lead-lag controller. It consists of gain block, is not a unique presentation.
washout block, lead-lag compensator block. The washout
block is considered as a high-pass filter, with the time
constant TW. Without this block steady changes in input
would modify the output. The value of TW is not critical
and may be in the range of 1 to 20 seconds. In this study,
the parameters obtained from lead-lag controller design that
is presented in [15], were used.
II. Adaptive Neuro-Fuzzy Controller Design Figure.2. A fuzzy system defined by a neural network.
Another controller is adaptive neuro-fuzzy
controller. In this section, we will present the procedure of With regard to the explanations presented and with the help
designing of the adaptive neuro-fuzzy controller. In this of MATLAB software, adaptive neuro-fuzzy controller can
research, the neuro fuzzy controller has 2 inputs that are Δδ be designed. The rules surface for designed controller is
and Δω and it has 1 output that is f ∈ {∆𝑚E, ∆𝛿 E, ∆𝑚B, ∆𝛿 B shown in figure 3.
}. For each input 20 membership functions and also 20
rules in the rules base is considered. Figure 5 demonstrates
the structure of adaptive neuro-fuzzy controller for a sugeno
fuzzy model with 2 inputs and 20 rules [20].
Fig.3 The rules surface
The membership functions for input variable ∆𝜔 are
Fig.3 ANFIS architecture for a two-input Sugeno fuzzy
presented in figure 4.
model with 20 rules
In Figure 3, a Sugeno type of fuzzy system has the rule
base with rules such as follows:
1. If Δδ is A1 and Δω is B1 then f1=p1 Δδ+q1 Δω+r1.
2. If Δδ is A2 and Δω is B2 then f2=p2 Δδ+q2 Δω+r2.
𝜇 𝐴𝑖 and 𝜇 𝐵 𝑖 are the membership functions of fuzzy sets Ai
and Bi for i=1,…,20. In evaluating the rules, we choose
product for T-norm (logical and). Then controller could be
designed in following steps:
1. Evaluating the rule premises:
𝑤 𝑖 = 𝜇 𝐴 𝑖 (Δ𝛿) 𝜇 𝐵 𝑖 (∆𝜔), i= 1.....20 (2) Fig.4 The membership functions for input variable ∆𝜔
2.Evaluating the implication and the rule consequences:
𝑤 1 ∆𝛿,∆𝜔 𝑓1 (∆𝛿,∆𝜔 )+⋯+𝑤 20 (∆𝛿 ,∆𝜔 )𝑓 20 (∆𝛿 ,∆𝜔 ) One of the advantages of using neuro-fuzzy controller is
f(∆𝛿, ∆𝜔) =
𝑤 1(∆𝛿 ,∆𝜔 ) +⋯+𝑤 20(∆𝛿 ,∆𝜔 ) that we can utilize one of the designed controllers for
Or leaving the arguments out instance Δme controller in place of the other controllers.
𝑤 1 𝑓1 +⋯+𝑤 20 𝑓20
While if we use conventional lead-lag controllers, for each
f =
𝑤 1 +⋯+𝑤 20
(3) control parameters, a controller must be designed.
This can be separated to phases by first defining
𝑤𝑖
V. SIMULATION RESULTS
w¯i = (4) In this research, two different cases are studied.
𝑤 1 +⋯+𝑤 20
In the first case mechanical power and in the second case
These are called normalized firing strengths. Then f can be
reference voltage has step change and deviation in ω (Δω)
written as
and deviation in rotor angle δ (Δδ) is observed. The
f = w¯1f1+......+ w20f20 (5) parameter values of system are gathered in Appendix. In
The above relation is linear with respect to pi , qi, ri first case, step change in mechanical input power is studied.
and i=1,…,20. So parameters can be categorized into 2 sets: Simulations are performed when mechanical input power
set of linear parameters and set of nonlinear parameters. has 10% increase (ΔPm=0.1 pu) at t=1 s. Simulation results
Now Hybrid learning algorithm can be applied to obtain for different types of loads and controllers ( ΔmE, ΔδE,
values of parameters. Hybrid learning algorithm is
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ΔmB, ΔδB ) and step change in mechanical input power are demonstrates simulation result for step change in reference
shown in figures 5 to 9. voltage, under nominal load and for δb Controller.
Generator Parameters :
M = 2H = 8.0MJ /MVA , D = 0.0, Td0’ = 5.044S
Xd = 1.0pu , Xq = 0.6 , Xd „ = 0.3
Exciter (IEEE Type ST1): 𝑘 𝐴 = 100, TA = 0.01S
Reactances: XIE = 0.1 pu , XE = XB =0.1 pu,
XBv = 0.3 pu, XE = 0.5 pu
Operation Condition: Pe = 0.8 pu, Vt = Vb=1.0 pu
UPFC parameters: mE = 0.4013, mB = 0.0789,
δE = -85.3478° , δB = -78.2174°
DC link: Vdc = 2 pu, Cdc = 1 pu
Fig. 10 Response of angular velocity for 5% step change in
reference voltage in the case of nominal load (δb
Controller)
Consequently simulation results show that neuro-
fuzzy controller successfully increases damping rate and
decreases the amplitude of low frequency oscillations.
Results comparison between conventional lead-lag
compensator and the proposed neuro-fuzzy controller for
the UPFC indicates that the proposed neuro-fuzzy controller
has less settling time and less overshoot in comparison with
Fig.7 Angular velocity deviation during step change in the conventional lead-lag compensator.
mechanical input power for nominal load (δe Controller)
VI. CONCLUSIONS
With regard to UPFC capability in transient
stability improvement and damping LFO of power systems,
an adaptive neuro-fuzzy controller for UPFC was presented
in this paper. The controller was designed for a single
machine infinite bus system. Then simulation results for the
system including neurofuzzy controller were compared with
simulation results for the system including conventional
lead-lag controller. Simulations were performed for
different kinds of loads. Comparison. showed that the
proposed adaptive neuro-fuzzy controller has good ability
Fig.8 Angular velocity deviation during step change in to reduce settling time and reduce amplitude of LFO. Also
mechanical input power for nominal load (mb Controller) we can utilize advantages of neural networks such as the
ability of adapting to changes, fault tolerance capability,
recovery capability, High-speed processing because of
parallel processing and ability to build a DSP chip with
VLSI Technology. Fuzzy logic is a convenient way to map
an input space to an output space. Mapping input to output
is the starting point for everything.
REFERENCES
[1] N. G. Hingorani and L. Gyugyi, Understanding
FACTS: Concepts and Technology of Flexible AC
Transmission System, IEEE Press, 2000.
Fig.9 Angular velocity deviation during step change in [2] H.F.Wang, F.J.Swift," A Unified Model for the
mechanical input power for nominal load (δb Controller) Analysis of FACTS Devices in Damping Power
System Oscillations Part I: Single-machine Infinite-
As it can be seen from figures 5 to 9, lead-lag bus Power Systems", IEEE Transactions on Power
controller response is not as good as neuro-fuzzy controller Delivery, Vol. 12, No. 2, April 1997, pp.941-946.
response and also neuro-fuzzy controller decreases settling [3] L. Gyugyi, C.D. Schauder, S.L. Williams,
time. In addition maximum overshoot has decreased in T.R.Rietman, D.R. Torgerson, A. Edris, "The Unified
comparison with lead-lag controller response. In second Power Flow Controller: A New Approach to
case, simulations were performed when reference voltage PowerTransmission Control", IEEE Trans., 1995, pp.
has 5% increase (ΔVref = 0.05 pu) at t=1 s. Figure 10 1085-1097.
www.ijmer.com 4218 | Page
5. International Journal of Modern Engineering Research (IJMER)
www.ijmer.com Vol.2, Issue.6, Nov-Dec. 2012 pp-4215-4219 ISSN: 2249-6645
[4] Wolanki, F. D. Galiana, D. McGillis and G. Joos, 13] A. Oudalov, R. Cherkaoui, A.J. Germond,
“Mid-Point Sitting of FACTS Devices in "Application of fuzzy logic techniques for the
Transmission Lines,” IEEE Transactions on Power coordinated power flow control by multiple series
Delivery, vol. 12, No. 4, 1997, pp. 1717-1722. FACTS devices", IEEE Power Engineering Society
[5] M. Noroozian, L. Angquist, M. Ghandari, and G. International Conference, 2001, pp. 74 – 80.
Anderson, “Use of UPFC for optimal power flow [14] Karbalaye Zadeh, M. Khatami, V. Lesani, H. Ravaghi,
control”, IEEE Trans. on Power Systems, vol. 12, no. H. A., " A fuzzy control strategy to damp multi mode
4, 1997, pp. 1629–1634. oscillations of power system considering UPFC", 8th
[6] A Nabavi-Niaki and M R Iravani. „Steady-state and International Conference on Advances in Power
Dynamic Models of Unified Power Flow Controller System Control, Operation and Management, 2009,
(UPFC) for Power System Studies.‟ IEEE p.1.
Transactions on Power Systems, vol 11, 1996, p 1937. [15] N. Tambey, M.L. Kothari, Damping of power system
[7] K S Smith, L Ran, J Penman. „Dynamic Modelling of oscillations with unified power flow controller
a Unified Power Flow Controller.‟ IEE Proceedings- (UPFC), IEE Proc.-Gener. Transm. Distrib., Vol. 150,
C, vol 144, 1997, pp.7. No. 2, March 200.
[8] H F Wang. „Damping Function of Unified Power [16] Khan, L. Ahmed, N. Lozano, C., "GA neuro-fuzzy
Flow Controller.‟ IEE Proceedings-C, vol 146, no 1, damping control system for UPFC to enhance power
January 1999, p 81. system transient stability", 7th International Multi
[9] H. F. Wang, F. J. Swift, “A Unified Model for the Topic Conf., 2003., pp. 276 – 282.
Analysis of FACTS Devices in Damping Power [17] Ruban Deva Prakash, T. Kesavan Nair, N., "A Robust
System Oscillations Part I: Single-machine Infinite- Control Strategy for UPFC to Improve Transient
bus Power Systems,” IEEE Transactions on Power Stability Using Fuzzy Bang-Bang Control",
Delivery, Vol. 12, No. 2, April, 1997, pp. 941-946. International Conference on Computational
[10] P.Kundur,"Power System Stability and Control”, Intelligence and Multimedia Applications, 2007, pp.
McGraw-Hill. 352 – 356.
[11] M. Banejad, A. M. Dejamkhooy , N. Talebi, " Fuzzy [18] Jang-Cheol Seo Seung-Il Moon Jong-Keun Park Jong-
Logic Based UPFC Controller for Damping Low Woong Choe, " Design of a robust UPFC controller
Frequency Oscillations of Power Systems", 2nd IEEE for enhancing the small signal stability in the multi-
International Conference on Power and Energy, 2008, machine power systems", IEEE Power Engineering
pp. 85-88. Society Winter Meeting, 2001, pp. 352-356.
[12] P.K., Dash, S. Mishra, G. Panda, , "Damping [19] Rahim, A.H.M.A. Al-Baiyat, S.A., "A robust damping
multimodal power system oscillation using a hybrid controller design for a unified power flow controller",
fuzzy controller for series connected FACTS devices", 39th International Universities Power Engineering
IEEE Trans. on Power Systems, Vol. 15, 2000, pp. Conference, 2004, pp. 265 – 269.
1360 -1366. [20] Jyh-Shing Roger Jang, Chuen-Tsai Sun, Eiji Mizutani,
" Neuro-fuzzy and soft computing: a computational
approach to learning and machine intelligence",
Prentice-Hall, 1997.
.
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