IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
1. The document discusses the design of a five-level inverter based DSTATCOM using fuzzy logic to enhance power quality in distribution systems. It aims to improve issues like voltage dips.
2. A simulation model of the DSTATCOM is created using MATLAB/Simulink. The DSTATCOM contains a voltage source converter that can generate sinusoidal voltages of varying magnitude, frequency and phase angle to mitigate voltage dips.
3. Simulation results will evaluate the performance of the voltage controller for the DSTATCOM in regulating voltage at sensitive load points under grid disturbances.
Analysis of Total Harmonic Distortion (THD) Level of Distribution Network Usi...IJERA Editor
The modern sensitive, Non-linear and sophisticated load affects the power quality. Dynamic Voltage Restorer (DVR) provides the fast, flexible and efficient solution to improve the power quality for such distribution network [8]. The active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operations are the major source of affecting power quality. The intent of this paper is to demonstrate the improvements obtained with DVR in power system network using MATLAB/SIMULINK. In this paper, an overview of the DVR, its functions, configurations, components, control strategies are reviewed. The Simulation results are presented to illustrate the performance of DVR in Total Harmonic Distortion (THD). The results showed clearly the performance of using DVR in improving THD level.
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.
This document discusses the application of a Distributed Static Series Controller (DSSC) modified with fuzzy logic and adaptive neuro-fuzzy inference system (ANFIS) controllers to mitigate sub-synchronous resonance (SSR) in series compensated power systems. SSR can cause shaft damage in turbine generators. The paper proposes using DSSC, a distributed FACTS device, with auxiliary damping controllers based on fuzzy logic and ANFIS to provide effective damping. Simulations using MATLAB/Simulink show that a DSSC combined with ANFIS controller is effective at damping SSR oscillations compared to conventional controllers.
A Fuzzy Logic controller based Multifunctional Dynamic Voltage restorer in Di...IOSR Journals
This document describes a study that proposes using a fuzzy logic controller with a flux-charge model feedback algorithm to control a dynamic voltage restorer (DVR) in a distribution system. The DVR aims to improve transient response and eliminate steady-state error during voltage sags and other disturbances. Simulation results on a test system show the DVR can successfully compensate for a three-phase short circuit fault and voltage sag from starting a large induction motor, maintaining the load voltage at normal levels in less than half a cycle in both cases.
IRJET-Simulation and Modeling of Dynamic Voltage Restorer for Compensation Of...IRJET Journal
The document describes the simulation and modeling of a dynamic voltage restorer (DVR) for mitigating voltage sags and swells in a power distribution system. A DVR is a custom power device that injects voltage in series with the distribution line to regulate the voltage at a load. The simulation model includes a DVR connected between a power source and sensitive load. Simulation results show that during a 50% voltage sag or 25% voltage swell, the DVR is able to quickly inject the appropriate compensating voltage to keep the load voltage at its nominal level. The DVR utilizes a control scheme based on dq0 transformation to identify voltage disturbances and determine the offset voltage required for compensation.
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.
Nonlinear Control of UPFC in Power System for Damping Inter Area OscillationsIJMER
This document summarizes a research paper about using nonlinear control of Unified Power Flow Controllers (UPFCs) to damp inter-area oscillations in power systems. The paper proposes a nonlinear control method where UPFCs can control their interface bus angles to mitigate power system oscillations. The control method develops a reduced nonlinear model of the network and uses selected frequency measurements from a subset of dominant machines as inputs to FACTS controllers. The effectiveness of using this method with UPFCs to damp inter-area oscillations is validated on a test power system.
1. The document discusses the design of a five-level inverter based DSTATCOM using fuzzy logic to enhance power quality in distribution systems. It aims to improve issues like voltage dips.
2. A simulation model of the DSTATCOM is created using MATLAB/Simulink. The DSTATCOM contains a voltage source converter that can generate sinusoidal voltages of varying magnitude, frequency and phase angle to mitigate voltage dips.
3. Simulation results will evaluate the performance of the voltage controller for the DSTATCOM in regulating voltage at sensitive load points under grid disturbances.
Analysis of Total Harmonic Distortion (THD) Level of Distribution Network Usi...IJERA Editor
The modern sensitive, Non-linear and sophisticated load affects the power quality. Dynamic Voltage Restorer (DVR) provides the fast, flexible and efficient solution to improve the power quality for such distribution network [8]. The active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operations are the major source of affecting power quality. The intent of this paper is to demonstrate the improvements obtained with DVR in power system network using MATLAB/SIMULINK. In this paper, an overview of the DVR, its functions, configurations, components, control strategies are reviewed. The Simulation results are presented to illustrate the performance of DVR in Total Harmonic Distortion (THD). The results showed clearly the performance of using DVR in improving THD level.
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.
This document discusses the application of a Distributed Static Series Controller (DSSC) modified with fuzzy logic and adaptive neuro-fuzzy inference system (ANFIS) controllers to mitigate sub-synchronous resonance (SSR) in series compensated power systems. SSR can cause shaft damage in turbine generators. The paper proposes using DSSC, a distributed FACTS device, with auxiliary damping controllers based on fuzzy logic and ANFIS to provide effective damping. Simulations using MATLAB/Simulink show that a DSSC combined with ANFIS controller is effective at damping SSR oscillations compared to conventional controllers.
A Fuzzy Logic controller based Multifunctional Dynamic Voltage restorer in Di...IOSR Journals
This document describes a study that proposes using a fuzzy logic controller with a flux-charge model feedback algorithm to control a dynamic voltage restorer (DVR) in a distribution system. The DVR aims to improve transient response and eliminate steady-state error during voltage sags and other disturbances. Simulation results on a test system show the DVR can successfully compensate for a three-phase short circuit fault and voltage sag from starting a large induction motor, maintaining the load voltage at normal levels in less than half a cycle in both cases.
IRJET-Simulation and Modeling of Dynamic Voltage Restorer for Compensation Of...IRJET Journal
The document describes the simulation and modeling of a dynamic voltage restorer (DVR) for mitigating voltage sags and swells in a power distribution system. A DVR is a custom power device that injects voltage in series with the distribution line to regulate the voltage at a load. The simulation model includes a DVR connected between a power source and sensitive load. Simulation results show that during a 50% voltage sag or 25% voltage swell, the DVR is able to quickly inject the appropriate compensating voltage to keep the load voltage at its nominal level. The DVR utilizes a control scheme based on dq0 transformation to identify voltage disturbances and determine the offset voltage required for compensation.
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.
Nonlinear Control of UPFC in Power System for Damping Inter Area OscillationsIJMER
This document summarizes a research paper about using nonlinear control of Unified Power Flow Controllers (UPFCs) to damp inter-area oscillations in power systems. The paper proposes a nonlinear control method where UPFCs can control their interface bus angles to mitigate power system oscillations. The control method develops a reduced nonlinear model of the network and uses selected frequency measurements from a subset of dominant machines as inputs to FACTS controllers. The effectiveness of using this method with UPFCs to damp inter-area oscillations is validated on a test power system.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
The document describes a proposed control scheme for a dynamic voltage restorer (DVR) to improve performance under various load conditions. The control scheme uses least error squares filters to estimate voltage magnitudes and phases, enabling accurate sag detection and compensation. It controls each phase independently using proportional-integral controllers in an outer loop and proportional controllers in an inner loop to damp filter resonances. Simulation results show the DVR can restore voltages within 5 milliseconds under both linear and non-linear loads for faults like single line-to-ground and line-to-line.
This paper deals with subsynchronous resonance (SSR) phenomena in a capacitive series-compensated DFIG-based wind farm. Using both modal analysis and time-domain simulation, it is shown that the DFIG wind farm is potentially unstable due to the SSR mode. In order to damp the SSR, the rotor-side converter (RSC) and grid-side converter (GSC) controllers of the DFIG are utilized. The objective is to design a simple proportional SSR damping controller (SSRDC) by properly choosing an optimum input control signal (ICS) to the SSRDC block, so that the SSR mode becomes stable without decreasing or destabilizing the other system modes. Moreover, an optimum point within the RSC and GSC controllers to insert the SSRDC is identified. Three different signals are tested as potential ICSs including rotor speed, line real power, and voltage across the series capacitor, and an optimum ICS is identified using residue-based analysis and root-locus method. Moreover, two methods are discussed in order to estimate the optimum ICS, without measuring it directly. The studied power system is a 100 MW DFIG-based wind farm connected to a series-compensated line whose parameters are taken from the IEEE first benchmark model (FBM) for computer simulation of the SSR. MATLAB/Simulink is used as a tool for modeling and designing the SSRDC, and power system computer aided design/electromagnetic transients including dc (PSCAD/EMTDC) is used to perform time-domain simulation for design process validation.
1) The document compares the effectiveness of TCSC (Thyristor Controlled Series Capacitor) and SSSC (Static Synchronous Series Compensator) in damping sub-synchronous oscillations in power systems.
2) It describes the control structures of TCSC and SSSC, which include a PI controller and supplementary sub-synchronous damping controller (SSDC) that takes the rotor speed deviation as input.
3) Simulation results on the IEEE second benchmark model show that SSSC has superior ability to damp sub-synchronous oscillations compared to TCSC when subjected to disturbances like a change in input mechanical power or disconnection of a transmission line.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
This document summarizes a research paper on improving voltage stability and reducing losses in distribution networks through distributed generation. The paper analyzes how distributed generation capacity and location can enhance voltage stability in a real distribution network. It presents a method to determine the steady-state voltage stability region of each bus in a distribution system. Simulation results show that distributed generation can reduce line losses by supplying power locally, with losses decreasing as generation is placed closer to loads. Both the capacity and location of distributed generation significantly impact line losses.
The document discusses power system stabilizers (PSS) and provides context for the thesis. It summarizes that the thesis will investigate modifying the input signal of a specific type of PSS and apply it to a power system to damp low frequency oscillations, without providing an exhaustive literature review. Details of the PSS structure, tuning methods, and considered input signals are given in later chapters.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Voltage Sag and Harmonics Mitigation using Distributed Power Flow ControllerIRJET Journal
The document describes a Distributed Power Flow Controller (DPFC) that is presented as a new power flow controlling device to mitigate voltage sags and harmonics. The DPFC improves upon the Unified Power Flow Controller (UPFC) by eliminating the common DC link and distributing the series converter into multiple low-rating single-phase converters. This greatly reduces costs and improves reliability compared to the UPFC. The DPFC allows independent operation of the shunt and series converters, with active power exchanged through the transmission line at the third harmonic frequency instead of through a common DC link. The DPFC is simulated in MATLAB/Simulink to validate its ability to improve power quality during different types of faults.
Simulation and Comparison of DVR and DSTATCOM Used for voltage sag mitigation...paperpublications3
Abstract: Power Quality problem in a system leads to various disturbances such as voltage fluctuations, transients and waveform distortions that results in a mis-operation or a failure of end user equipment. There are different types of custom power devices like Distribution Static Compensator (D-STATCOM) and Dynamic Voltage Restorer (DVR) which can effectively use for mitigation of different type of power quality problems. This paper describes the technique of correcting the supply voltage sag distributed system and also describes performance comparison are presented between DVR and DSTATCOM to know how both the devices successfully been applied to power system for regulating system voltage effectively. DSTATCOM and DVR both of them based on VSI principle. A DVR is a series compensation device which injects a voltage in series with system and a DSTATCOM is a shunt compensation device which injects a current into the system to correct the power quality problems. This paper presents a power system operation with PI controller with abc to dq0 convertor approach. Total Harmonics Distortion (THD) is also calculated for the system with and without compensation. Results are presented to assess the performance of devices as a potential custom power solution. Improve dynamic voltage control and thus increase system load ability. This paper presents modeling and simulation of DVR & DSTATCOM in MATLAB/Simulink.
DVR with Artificial Intelligent Controller for Voltage Sag MitigationMohamed Khaleeel
The document discusses two types of fuzzy inference systems - Mamdani-type and Sugeno-type - that can be used to control a Dynamic Voltage Restorer (DVR) to mitigate voltage sags. It outlines the basic differences between the two systems, including that Mamdani-type FIS has output membership functions while Sugeno-type FIS does not. Both systems were simulated in MATLAB with two inputs (error and change in error) and one output to evaluate their performance in compensating voltage sags.
This document summarizes a research paper that analyzes the performance of a STATCOM (Static Synchronous Compensator) under various power system faults. It proposes an "emergency PWM" control strategy to prevent overcurrents in the voltage source converter (VSC) during faults, allowing the STATCOM to continue supplying reactive power support when needed. Simulation results are presented for a 48-pulse VSC-based ±100 MVAR STATCOM connected to a 2-bus power system, validating that the emergency PWM strategy prevents overcurrents and allows reactive power support during line-to-ground faults.
The document analyzes water quality parameters of the Vaigai River in Tamil Nadu, India. Samples were collected from three locations along the river on a monthly basis and tested for total dissolved solids, total suspended solids, electrical conductivity, dissolved oxygen, and magnesium. The results found that two of the sampling locations had water quality issues like high dissolved solids and magnesium that require treatment for drinking. Water quality was generally better during monsoon seasons with more rainfall. The study aims to evaluate the river's water resources and classify them for different uses.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document describes the design of a custom cryptographic processor for implementing symmetric key operations. The processor is implemented on an FPGA using Verilog. It includes instruction units to perform logical operations, arithmetic operations, and finite field arithmetic needed for symmetric key algorithms like AES, Blowfish, RC5, RC6, IDEA. The processor is pipelined for high speed and includes modules for an ALU, control unit, registers, and multiplexers. Experimental results showed the processor operates at high speed with low area and delay compared to a general purpose processor.
The document describes a genetic algorithm approach to optimizing the design of steel-concrete composite plane frames to minimize cost. Key points:
- The algorithm uses genetic algorithms to determine the optimal sizes of composite beams and columns that minimize total frame cost while satisfying strength, serviceability, and other design constraints.
- Design variables are the cross-sectional properties of beams and columns. The algorithm evaluates candidate designs, analyzes the frame, and checks if designs satisfy constraints.
- The best designs are kept in subsequent generations while weaker designs are removed, simulating natural selection. This process iterates to find the optimal composite frame design.
- The approach is demonstrated on 2x3 and 2x5 frame examples,
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
The document describes a proposed control scheme for a dynamic voltage restorer (DVR) to improve performance under various load conditions. The control scheme uses least error squares filters to estimate voltage magnitudes and phases, enabling accurate sag detection and compensation. It controls each phase independently using proportional-integral controllers in an outer loop and proportional controllers in an inner loop to damp filter resonances. Simulation results show the DVR can restore voltages within 5 milliseconds under both linear and non-linear loads for faults like single line-to-ground and line-to-line.
This paper deals with subsynchronous resonance (SSR) phenomena in a capacitive series-compensated DFIG-based wind farm. Using both modal analysis and time-domain simulation, it is shown that the DFIG wind farm is potentially unstable due to the SSR mode. In order to damp the SSR, the rotor-side converter (RSC) and grid-side converter (GSC) controllers of the DFIG are utilized. The objective is to design a simple proportional SSR damping controller (SSRDC) by properly choosing an optimum input control signal (ICS) to the SSRDC block, so that the SSR mode becomes stable without decreasing or destabilizing the other system modes. Moreover, an optimum point within the RSC and GSC controllers to insert the SSRDC is identified. Three different signals are tested as potential ICSs including rotor speed, line real power, and voltage across the series capacitor, and an optimum ICS is identified using residue-based analysis and root-locus method. Moreover, two methods are discussed in order to estimate the optimum ICS, without measuring it directly. The studied power system is a 100 MW DFIG-based wind farm connected to a series-compensated line whose parameters are taken from the IEEE first benchmark model (FBM) for computer simulation of the SSR. MATLAB/Simulink is used as a tool for modeling and designing the SSRDC, and power system computer aided design/electromagnetic transients including dc (PSCAD/EMTDC) is used to perform time-domain simulation for design process validation.
1) The document compares the effectiveness of TCSC (Thyristor Controlled Series Capacitor) and SSSC (Static Synchronous Series Compensator) in damping sub-synchronous oscillations in power systems.
2) It describes the control structures of TCSC and SSSC, which include a PI controller and supplementary sub-synchronous damping controller (SSDC) that takes the rotor speed deviation as input.
3) Simulation results on the IEEE second benchmark model show that SSSC has superior ability to damp sub-synchronous oscillations compared to TCSC when subjected to disturbances like a change in input mechanical power or disconnection of a transmission line.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
This document summarizes a research paper on improving voltage stability and reducing losses in distribution networks through distributed generation. The paper analyzes how distributed generation capacity and location can enhance voltage stability in a real distribution network. It presents a method to determine the steady-state voltage stability region of each bus in a distribution system. Simulation results show that distributed generation can reduce line losses by supplying power locally, with losses decreasing as generation is placed closer to loads. Both the capacity and location of distributed generation significantly impact line losses.
The document discusses power system stabilizers (PSS) and provides context for the thesis. It summarizes that the thesis will investigate modifying the input signal of a specific type of PSS and apply it to a power system to damp low frequency oscillations, without providing an exhaustive literature review. Details of the PSS structure, tuning methods, and considered input signals are given in later chapters.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
to stay connected to the grid in fault situations delivering the reactive current specified in the recent
grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
wind turbines.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Voltage Sag and Harmonics Mitigation using Distributed Power Flow ControllerIRJET Journal
The document describes a Distributed Power Flow Controller (DPFC) that is presented as a new power flow controlling device to mitigate voltage sags and harmonics. The DPFC improves upon the Unified Power Flow Controller (UPFC) by eliminating the common DC link and distributing the series converter into multiple low-rating single-phase converters. This greatly reduces costs and improves reliability compared to the UPFC. The DPFC allows independent operation of the shunt and series converters, with active power exchanged through the transmission line at the third harmonic frequency instead of through a common DC link. The DPFC is simulated in MATLAB/Simulink to validate its ability to improve power quality during different types of faults.
Simulation and Comparison of DVR and DSTATCOM Used for voltage sag mitigation...paperpublications3
Abstract: Power Quality problem in a system leads to various disturbances such as voltage fluctuations, transients and waveform distortions that results in a mis-operation or a failure of end user equipment. There are different types of custom power devices like Distribution Static Compensator (D-STATCOM) and Dynamic Voltage Restorer (DVR) which can effectively use for mitigation of different type of power quality problems. This paper describes the technique of correcting the supply voltage sag distributed system and also describes performance comparison are presented between DVR and DSTATCOM to know how both the devices successfully been applied to power system for regulating system voltage effectively. DSTATCOM and DVR both of them based on VSI principle. A DVR is a series compensation device which injects a voltage in series with system and a DSTATCOM is a shunt compensation device which injects a current into the system to correct the power quality problems. This paper presents a power system operation with PI controller with abc to dq0 convertor approach. Total Harmonics Distortion (THD) is also calculated for the system with and without compensation. Results are presented to assess the performance of devices as a potential custom power solution. Improve dynamic voltage control and thus increase system load ability. This paper presents modeling and simulation of DVR & DSTATCOM in MATLAB/Simulink.
DVR with Artificial Intelligent Controller for Voltage Sag MitigationMohamed Khaleeel
The document discusses two types of fuzzy inference systems - Mamdani-type and Sugeno-type - that can be used to control a Dynamic Voltage Restorer (DVR) to mitigate voltage sags. It outlines the basic differences between the two systems, including that Mamdani-type FIS has output membership functions while Sugeno-type FIS does not. Both systems were simulated in MATLAB with two inputs (error and change in error) and one output to evaluate their performance in compensating voltage sags.
This document summarizes a research paper that analyzes the performance of a STATCOM (Static Synchronous Compensator) under various power system faults. It proposes an "emergency PWM" control strategy to prevent overcurrents in the voltage source converter (VSC) during faults, allowing the STATCOM to continue supplying reactive power support when needed. Simulation results are presented for a 48-pulse VSC-based ±100 MVAR STATCOM connected to a 2-bus power system, validating that the emergency PWM strategy prevents overcurrents and allows reactive power support during line-to-ground faults.
The document analyzes water quality parameters of the Vaigai River in Tamil Nadu, India. Samples were collected from three locations along the river on a monthly basis and tested for total dissolved solids, total suspended solids, electrical conductivity, dissolved oxygen, and magnesium. The results found that two of the sampling locations had water quality issues like high dissolved solids and magnesium that require treatment for drinking. Water quality was generally better during monsoon seasons with more rainfall. The study aims to evaluate the river's water resources and classify them for different uses.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document describes the design of a custom cryptographic processor for implementing symmetric key operations. The processor is implemented on an FPGA using Verilog. It includes instruction units to perform logical operations, arithmetic operations, and finite field arithmetic needed for symmetric key algorithms like AES, Blowfish, RC5, RC6, IDEA. The processor is pipelined for high speed and includes modules for an ALU, control unit, registers, and multiplexers. Experimental results showed the processor operates at high speed with low area and delay compared to a general purpose processor.
The document describes a genetic algorithm approach to optimizing the design of steel-concrete composite plane frames to minimize cost. Key points:
- The algorithm uses genetic algorithms to determine the optimal sizes of composite beams and columns that minimize total frame cost while satisfying strength, serviceability, and other design constraints.
- Design variables are the cross-sectional properties of beams and columns. The algorithm evaluates candidate designs, analyzes the frame, and checks if designs satisfy constraints.
- The best designs are kept in subsequent generations while weaker designs are removed, simulating natural selection. This process iterates to find the optimal composite frame design.
- The approach is demonstrated on 2x3 and 2x5 frame examples,
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document analyzes friction stir welding tools with various threaded pin profiles. Three tool pin profiles are modeled in CATIA and analyzed using ANSYS: cylindrical, frustum, and conical pins with threads. The stress distributions and displacement vectors in the pins are obtained for different rotational speeds and temperatures. The results show that the cylindrical pin profile experiences the lowest stress levels and displacement compared to the other profiles. Increasing rotational speed does not significantly affect the stress, while higher temperatures generally increase stress across all pin profiles. The cylindrical pin profile is determined to be preferable for withstanding loads during friction stir welding.
The document summarizes research on synthesizing and characterizing fluorinated yttrium barium copper oxide (Y3Ba5Cu8Oy) superconducting compounds. X-ray diffraction analysis showed the compounds had an orthorhombic structure similar to YBa2Cu3O7, with a larger 'c' axis. Scanning electron microscopy revealed the grain size increased with higher fluorine content. Transition temperature measurements found the superconducting transition onset temperature increased with fluorine addition up to 0.6, likely due to optimization of oxygen stoichiometry, but saturated beyond that point due to disturbance of the optimum oxygen level. Overall, fluorine doping improved the superconducting properties of the samples.
This document analyzes the performance of different directional antennas for various routing protocols in mobile ad hoc networks. It compares omni-directional, steerable, and switched beam antennas using the DSR, OLSR, and ZRP routing protocols in terms of average jitter, end-to-end delay, throughput, and power consumption. The document outlines the characteristics and operation of each antenna type and routing protocol. It then describes the simulation setup using the QualNet simulator to evaluate and compare the performance of the antennas with the different routing protocols under various mobility scenarios.
This document presents a method for interactive image segmentation using constrained active contours. It begins with an overview of existing interactive segmentation techniques, including boundary-based methods like active contours/snakes and region-based methods like random walks and graph cuts. The proposed method initializes a contour using region-based segmentation then refines it using a convex active contour model that incorporates both regional information from seed pixels and boundary smoothness. This allows the contour to globally evolve to object boundaries while handling topology changes.
This document summarizes two GPU programming models - Accelerator and CUDA. It describes the basic steps in Accelerator programming including creating data arrays, loading them into data-parallel array objects, processing the arrays using Accelerator operations, creating a result object, and evaluating the result on a target processor. It also provides an example code showing the use of ParallelArrays and FloatParallelArray objects. The document then briefly introduces CUDA as a parallel computing platform and programming model for GPUs that provides lower and higher-level APIs.
Uso de mensajes de texto SMS que potencian el desarrollo de comunidades agr...RIBDA 2009
DatAgro es un proyecto chileno que utiliza mensajes de texto (SMS) para proporcionar información relevante a pequeños agricultores, con el objetivo de mejorar su productividad y desarrollo. El proyecto fue desarrollado por DataDyne.org y la Cooperativa Agrícola Coopeumo, y ha recibido reconocimientos internacionales. Los mensajes brindan información sobre prácticas agrícolas, precios, clima y noticias a agricultores con poca conectividad, aprovechando la alta penet
This document presents an optimal supplementary damping controller design for Thyristor Controlled Series Compensator (TCSC) using Real-Coded Genetic Algorithm (RCGA). TCSC is capable of improving power system stability by modulating reactance during disturbances. The document proposes using a multi-objective fitness function consisting of damping factors and real parts of eigenvalues to optimize the parameters of a TCSC-based supplementary damping controller using RCGA. Simulation results presented show the effectiveness of the proposed controller over a wide range of operating conditions and disturbances.
This document discusses modeling and analysis of a Thyristor Controlled Series Capacitor (TCSC) in a power system. It begins with background on TCSC and its benefits for power flow control. It then describes modeling a TCSC circuit using MATLAB Simulink. The model includes components like voltage sources, RLC branches, meters, and a thyristor block. Waveforms are analyzed for the TCSC in capacitive and inductive modes by varying the firing pulse delay. The response stabilizes after a few seconds. Fourier analysis shows the fundamental frequency reaching a new steady-state value with a change in firing angle. In conclusion, the modeling provides insights into the transient behavior and operation of a TCSC.
Thyristor Controlled Series Capacitor with Automatic Controlijiert bestjournal
An increasingly competitive market where economic a nd environmental pressures limit their scope to expand transmission facilities.The optimiz ation of transmission corridors for power transfer has become a great importance. In this sce nario,the FACTS technology is an attractive option for increasing system operation flexibility [1],New developments in high-current,high- power electronics are making it possible to control electronically the power flows on the high voltage side of the network during both steady stat e and transient operation. In this paper a series controller from the Flexible AC Transmission System (FACTS) family called as �Thyristor Controlled Series Capacitor� (TCSC) is designed using PIC microcontroller. Thyristor controlled series compensator (TCSC),is the first generation of FACTS controller,can govern line impedance through introduction of a thy ristor controlled capacitor in series with the transmission line. A grid of transmission lines ope rating at high voltages is required to transmit power from generating stations to load. In addition to transmission lines that carry power from source to load,modern power systems are highly int erconnected for economic reasons.
IJCER (www.ijceronline.com) International Journal of computational Engineeri...ijceronline
This document summarizes a study on using a Thyristor Controlled Series Capacitor (TCSC) to reduce power system oscillations. Key points:
1) A hybrid series compensation scheme is proposed using fixed capacitors on two phases and a TCSC on the third phase to maintain phase balance at power frequency but create imbalance at other frequencies.
2) Time domain simulations were conducted on a benchmark power system model using EMTP-RV software to evaluate the effectiveness of the hybrid scheme in damping oscillations.
3) Results showed the hybrid scheme has potential for enhancing power system dynamics by damping power swings and subsynchronous resonance oscillations.
This document discusses using a Thyristor Controlled Series Capacitor (TCSC) to enhance power system stability. It first reviews power system stability concepts like steady state, transient, and dynamic stability. It then discusses factors limiting transmission line loading capacity and introduces Flexible AC Transmission Systems (FACTS) technology. The document focuses on TCSC, explaining its working principle and applications. It presents simulation results in MATLAB showing that TCSC improves stability performance and dampens power oscillations under different loading conditions like light, nominal, and heavy loads. The conclusion is that TCSC effectively enhances power system stability.
IRJET- Optimization of Power Flow in Transmission Line using TCSC ControllersIRJET Journal
- The document discusses optimization of power flow in transmission lines using thyristor controlled series capacitors (TCSCs). TCSCs are flexible alternating current transmission system (FACTS) devices that can provide variable inductive and capacitive reactance.
- TCSCs allow increasing the power transfer capacity of transmission lines by reducing the line's inductive reactance. They do this by providing continuously variable series compensation for the line. TCSCs offer advantages over other series compensation methods like improving system stability and reducing losses.
- The document analyzes the circuit operation of TCSCs. It describes how TCSCs use thyristor controlled reactors (TCRs) in parallel with fixed capacitors to provide instantaneous
Optimum Location of TCSC by Sensitivity Factor Analysis for Congestion Manage...rahulmonikasharma
Due to deregulation of electric market transmission congestion occurs due insufficient transmission capacity to accommodate all constraints for transmission of a line. FACTS devices such as Gate Controlled Series Capacitor and Thyristor Control Series Compensator can help to reduce the flow in heavily loaded lines by controlling the power flow in the network. It increases the load ability of the network and reduces the cost of production. Congestion management using series connected FACTS devices can be done in two steps. First, find the optimal location of FACTS device and second, optimize the setting of the control parameter of FACTS device. Three methods to determine the optimal location of series connected FACTS device are discussed in this paper. The approach is based on sensitivity of line loss, total system loss and real power flow performance index. The proposed method has been demonstrated on 9-bus system in MATLAB programming as well as SIMULINK.
Modeling and Simulation of power system using SMIB with GA based TCSC controllerIOSR Journals
This document summarizes a study that uses genetic algorithms to tune a thyristor-controlled series compensator (TCSC) controller to improve the stability of a single-machine infinite-bus (SMIB) power system model. The study models the SMIB system and implements a TCSC to damp oscillations. Genetic algorithms are used to optimize the TCSC controller parameters. Simulation results show that the genetically-tuned TCSC controller more effectively damps oscillations compared to the system without a TCSC controller.
Efficacy of Facts in Power Oscillation Damping and Renewable IntegrationIOSRJEEE
This document summarizes research on using flexible AC transmission system (FACTS) devices to improve power oscillation damping and facilitate renewable energy integration. It discusses how power oscillations can lead to instability if not controlled and how FACTS devices like STATCOM and SVC can enhance stability. It presents simulations of the IEEE 14-bus system that demonstrate improved damping from these controllers. Eigenvalue analysis shows STATCOM shifts modes further into the stable region than SVC. Both STATCOM and SVC integration helps renewable sources by mitigating power quality issues to allow more distributed generation on the grid.
The document discusses improving power system performance using Flexible AC Transmission System (FACTS) devices. It describes three types of FACTS devices: Static Var Compensator (SVC), Thyristor Controlled Series Compensator (TCSC), and Unified Power Flow Controller (UPFC). The SVC and TCSC are able to control voltage and improve the voltage profile. Simulations showed adding FACTS devices decreased power losses and improved the voltage level. The UPFC can simultaneously control parameters like line impedance, voltage, and phase angle to regulate power flow.
Transient Stability Assessment and Enhancement in Power SystemIJMER
This document discusses transient stability assessment and enhancement in power systems. It first introduces transient stability and its importance. It then describes using PSAT software to analyze the IEEE 39-bus test system and calculate critical clearing times (CCTs) for different faults to assess stability. An artificial neural network is trained to predict CCTs at different operating points. Finally, particle swarm optimization is used to find the optimal placement of a thyristor controlled series capacitor to enhance stability by minimizing real power losses, increasing several CCTs above 0.1 seconds.
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
The document discusses Thyristor Controlled Series Compensation (TCSC), a FACTS device that uses thyristors to control the capacitive reactance of transmission lines. TCSC can enhance power flow, limit fault current, improve stability and transients. It introduces benefits like mitigating subsynchronous resonance risks, damping power oscillations, and improving post-contingency stability. TCSC operates in modes like blocking, bypass, capacitive boost and inductive boost to accurately regulate power flow and damp oscillations while increasing transmission capacity and stability.
Optimal Coordination of DOCR for Radial Distribution Systems in Presence of TCSCIJPEDS-IAES
Protective relays coordination is the process of determining the exact relay
settings such that the relay closes to the fault would operates faster than other
relays. The operating time of each relay depends on two independent
variables called Pickup current (Ip) and Time Dial Setting (TDS). In this
paper, a PSO algorithm has been presented to determine the coordination of
Directional Over-Current Relays (DOCRs) in presence of multi-system
FACTS devises. From the simulation result and analysis, the impact of TCSC
location in the in 33-bus distribution system on Directional Over-Current
Relays has been observed on the optimal relays settings as well as the
effectiveness of the proposed algorithm in finding optimal coordination of
directional over-current relays.
Enhancement of Power Quality by an Application FACTS DevicesIAES-IJPEDS
1) The document discusses the use of Flexible AC Transmission Systems (FACTS) devices like Thyristor Controlled Series Capacitor (TCSC) and Thyristor Controlled Reactor (TCR)-based Static VAR Compensator (SVC) to enhance power quality and transmission capability.
2) It presents simulation models of TCSC and TCR-SVC developed using MATLAB/Simulink. The simulations show that these FACTS devices can effectively reduce voltage drops, electrical losses in long transmission lines, and improve stability.
3) Student feedback indicates the models are easy to use and effective for learning about controlled reactor compensators, series capacitor compensators, and reactive power/voltage
Locating Facts Devices in Optimized manner in Power System by Means of Sensit...IJERA Editor
This paper presents a new method to find the optimal location of facts devices by analyzing sensitivity . The optimal location and capability of Static Var Compensator (SVC) and Thyristor Controlled Series Capacitor (TCSC) in transmission line is investigated for enchasing the power transfer capability and stability of the system. The method firstly put all the buses in the order by voltage reactive power sensitivity and then chooses the optimal location and appropriate capability of the facts devices. It is simple in computation and suitable for large scale interconnection power grid. The results obtained are satisfying and will be useful for enhancing the power system reliability
Transmission Congestion and Voltage Profile Management Using TCSC and TCPAR i...IJERA Editor
This document summarizes a research paper that examines using Flexible AC Transmission System (FACTS) devices like Thyristor Controlled Series Capacitor (TCSC) and Thyristor Controlled Phase Angle Regulator (TCPAR) to manage transmission congestion and improve voltage profiles in deregulated power systems. It provides mathematical models for TCSC and TCPAR and describes using sensitivity analysis to optimally place these FACTS devices. The method is demonstrated on modified IEEE 14-bus and IEEE 24-bus test systems in PowerWorld Simulator software, showing it can effectively relieve line congestion.
1) The document describes a new FACTS device called the Gate Controlled Series Capacitor (GCSC) for controlling power flow in transmission lines.
2) The GCSC uses semiconductor switches connected in parallel with a capacitor to continuously vary the equivalent series reactance. This allows control of power flow without the limitations of existing thyristor controlled series compensation devices.
3) Simulations show the GCSC's ability to control power flow and damp power oscillations in transmission systems, demonstrating its effectiveness as an alternative to other series compensation technologies like the thyristor controlled series capacitor (TCSC).
Implementation Of Thyristor Controlled Series Capacitor (TCSC) In Transmissio...IJERA Editor
A grid of transmission lines operating at high or extra high voltages is required to transmit power from
generating stations to load. In addition to transmission lines that carry power from source to load, modern power
systems are highly interconnected for economic reasons. The large interconnected transmission networks are
prone to faults due to the lightning discharges and reduce insulation strength. Changing of loads and atmosphere
conditions are unpredictable factors. This may cause overloading of lines due to which voltage collapse takes
place. These problems can be eased by providing sufficient margin of working parameters and power transfer,
but it is not possible due to expansion of transmission network. Still the required margin is reduced by
introduction of fast dynamic control over reactive and active power by high power electronic controllers. This
paper describes about implementation of Thyristor Controlled Series Capacitor (TCSC) in transmission line
model in order to enhance power flow at the receiving end. The triggering pulses to the thyristor are given using
Arduino.
Implementation Of Thyristor Controlled Series Capacitor (TCSC) In Transmissio...
Kj2518171824
1. N.Srikanth, Atejasri / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1817-1824
ENHANCING POWER SYSTEM STABILITY BY USING Thyristor
Controlled Series Compensator
N.Srikanth (M.Tech)*, ATEJASRI-M.Tech**
Dept of EEE, GIET, RAJAHMUNDRY, A.P-INDIA,
Abstract
Passivity- based controller is designed for can provide the benefits of increased system stability,
the thyristor controlled series capacitor (TCSC) reduced system losses, and better voltage regulation
aimed at enhancing power system stability. The Protective distance relays, which make use of
design problem formulated as optimization impedance measurements in order to determine the
Problem and then particle swarm optimization presence and location of faults, are "fooled" by
(PSO) technique was used to search for optimal installed series. Capacitance on the line when the
parameters. The proposed control and technique presence or absence of the capacitor in the fault
are employed on test system under different cases circuit is not known a priori. This is because the
and location of TCSC. To validate the capacitance cancels or compensates some of the
effectiveness of the TCSC on enhancing system inductance of the line and therefore the relay may
stability, Eigen values analysis and nonlinear perceive a fault to be in its first zone when the fault
time-domain simulation implemented on SMIB is actually in the second or third zone of protection.
equipped with TCSC. The eigenvalue analysis and Similarly, first zone faults can be perceived to be
simulation results show the effectiveness and reverse faults! Clearly this can cause some costly
robustness of proposed controllers to improve the operating errors. The conventional protections like
stability performance of power system by efficient distance, differential, and by using relays power
damping of low frequency oscillations under controllers are very much in use nowadays.
various disturbances.
Recent trend to overcome those problems is
Keywords: Power system stability; Thyristor the application of FACTS technology, is being
Controlled Series Compensator; particle swarm promoted as a means to extend of FACTS
optimization; technology, is being promoted as a means to extend
the capacity of existing power transmission networks
I.INTRODUCTION to their limits without the necessity of adding new
Modern interconnected power systems are transmission lines There have been significant
large, complex and operated closer to security limits. activities and achievement research and application
Further more environmental Constraints restrict the of flexible AC transmission systems (FACTS).
expansion of transmission network and the need for Thyristor controlled series compensation (TCSC) is
long distance power transfers has increased as a an important device in the FACTS family. It can
result Stability has become a major concern in many have various roles in the operation and control of
power systems and many blackouts have where the power systems, such as scheduling power flow;
reason has been instability i.e. rotor angle instability, decreasing Unsymmetrical components and
voltage instability or frequency stability. Power enhancing transient stability.
system stabilizers (PSS) are now routinely used in
the industry to damp out power system oscillations. This was a very simple control; the
How ever, during some operating conditions, this maximum amount compensation was inserted at the
device may not produce adequate damping, observed same time that the faulted line was switched out
which detract from the overall system performance advances in high-power electronics, high-efficiency
and become unstable, and power input stabilizers power electronics have led to development of
were found to lead to large changes in the generator thyristor -controlled it can change its apparent
other effective alternatives are needed in addition to reactance .
PSS. These problems are well known [1-4].
TCSC is able to directly schedule the real
In order to meet the high demand for power power flow control by selected line and allow the
transmission capacity, some power companies have system to operate closer to the line limits. More
installed series capacitors on power transmission importantly because of its rapid and flexible
lines. This allows the impedance of the line to be regulation ability, it can imp rove transient stability to
lowered, thus yielding increased transmission and dynamic performance of the power systems.
capability. The series capacitor makes sense because [13].The objective of this paper is to study the impact
it's simple and could be installed for 15 to 30% of of TCSC on enhancing power system stability, when
the cost of installing a new transmission line, and it subjected to small or severe disturbances, as well as
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(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1817-1824
location of TCSC. To optimize the TCSC parameters C dv c=is(t)-iT(t) u………..................... (1)
particle swarm optimization (PSO) .Technique is dt
used to find optimal parameters and then location of L di T = VC u……..………….................. (2)
TCSC. The rotor speed deviation is used as objective dt
function. is (t) =I m cos (wt)……………………… (3)
Section (II) of this paper discusses modeling In equation (1) the switching variable u= 1 when
of TCSC while sections (III) derive dynamic the thyristor valves are conducting (S is closed), and
modeling of power system The rest of the sections are u= 0 when the thyristor are blocked(S is open) .
organized as follows: in section (IV) an over view of
particle swarm optimization is presented Section (V) VCF to IM:
formulation problem and o objective function are
derived. The simulation and results are presented in XTCSC=VCF = XC- X2C 2β+SIN2β+
section VI). Finally conclusions are discussed in IM XC-XL ∏
section (VII)
4X2C COS2β (K tan kβ –tan β)
II. TCSC MODELLING XC-XL (K2-1) ∏………………….. (4)
The basic TCSC configuration consists of a Or
series capacitor bank C in parallel with a thyristor-
controlled reactor and bypass inductor L as shown in XTCSC=VCF = XC- X2C σ+SINσ +
Figure.1. This simple model utilizes the concept of a IM XC-XL ∏
variable series reactance. The series reactance is
adjusted automatically within limits to keep the 4X2C COS2 (σ/2) (K tan (k σ/2) –tan (σ/2)
specified amount of active power flow across the line. XC-XL (K2-1)
There are certain values of inductive and capacitive
reactance which cause steady-state resonance. Generally, in a TCSC, two main operational
blocks can be clearly identified
A) An External control:
Control operates the controller Accomplish
specified compensation objectives; this control
directly relies on measured systems variables to
define the Reference for the internal control, which is
usually the value of the controller reactance. It may
be comprised of different control loops depending on
the control objectives. Typically the principal steady
The TCSC can be continuously controlled state function of a TCSC is power flow control,
either in capacitive or in inductive area, avoiding the which is usually accomplished either automatically
steady- state resonant region considering the three With a “slow” PI to guarantee steady-steady error –
basic operating modes of the TCSC: Thyristor free control Obeying specified limits concerning
blocked, Thyristor bypassed and Vernier operation. reactance or the firing angle, or manually through
The vernier mode is subdivided into two categories, direct operator intervention Additional functions for
namely: inductive vernier mode (900< α <αres) and stability improvement, such as damping controls may
capacitive vernier mode (αres <α < 1800) see Fig. 1. be included in the external control.
For the purposes of mathematical analysis a The equivalent impedance X’e Of the device is
simplified TCSC circuit is shown in fig.2. represented as a function of the firing angle based on
Transmission-line current I assumed to be the the assumption of a sinusoidal steady-state controller
independent-input variable and is modeled as an current. In this model, it is Possible to directly
external current source, is (t). It is further assumed represent some of the actual TCSC internal Control
that the line current is sinusoidal. Then the current blocks associated with the firing angle control, as
through the fixed series capacitor, thyristor valve i T Opposed to just modeling them with a first order lag
(t), and the line current I S (t),are expressed as function.
B)An Internal control:
provide appropriate gate drive signals for the
thyristor valve to produce the desired compensating
reactance Fig .3 shown below illustrate block diagram
of TCSC model used in this paper for both operation
Fig .2 A simplified TCSC circuit modes
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3. N.Srikanth, Atejasri / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1817-1824
WS dt2
d2δ = Ws (PM- PE)…….…………... (9)
dt2 2GH
From equation 6 δ value can be substituted
d2(θc-Wst) = Ws (PM- PE)……………(10)
dt2 2GH
Ẃs = WB {PM- PE- D (∆w)} …………… (11)
Fig .3 shown below illustrate block diagram of TCSC
model used in this paper for both operation modes 2H
The structure of the proposed stability control B.GENERATORELECTRICALDYNAMICS
loop is depicted in Fig. 3. It consists of a washout The internal voltage, Eq; equation i
filter to avoid a Controller response to the dc offset of
the input signal, a Dynamic compensator and a
limiter. The dynamic compensate or Consists of two …….... (12)
(or more) lead-lag blocks to provide the necessary In this work a simplified IEEE type –ST1A
phase-lead characteristics Finally, the limiter is used is used, which Can be representing by equation (15).
to improve controller response to large deviations in The inputs are the terminal Voltage (V t ) and
the input signal. reference voltage Vref . KA and TA are the gain and
time constant of the excitation system
III. DYNAMIC MODELING OF POWER
SYSTEM
In this paper, a simple single machine in
finite bus (SMIB) system is used as shown in fig .4. ……...…… (13)
The generator is represented by the third-order model. Where Pe,
The dynamics of the Machine in classical model, can
be represented by the following.
..................... (14)
Pe= Vq Iq +Vd Id……………………..................... (15)
….…………………………. (16)
Fig:4 single machine infinite bus Vd = Xd Id………………………………… (17)
A.MECHANICAL EQUATIONS ………………………... (18)
For Small-signal analysis, the lineraizedincremental
δ =θ e –w s t…………………….……… (5) model around a nominal operating point is usually
employed. The lineraized power system model can
δ·= w B (∆w) …………………………. (6) bewrittenas:
Here δ, w , H, D, PM and Pe are the angle, speed,
moment Inertia , damping coefficient, input
mechanical Power and output electrical power,
respectively, of the machine .To measure the angular
position of the rotor with respect to a synchronously
rotating frame of reference.
δ =θe -wst; rotor angular displacement from
synchronously rotating frame called ( torque
angle/power angle). Where,
M d2 δ = PM-PE…………………… (7)
dt2
2GH d2 δ = PM-PE………………… (8) …………………………..(19)
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Vol. 2, Issue 5, September- October 2012, pp.1817-1824
4) The above concept is explained using only XY
axis (2dimensional space). However, the method
can be easily applied to n dimensional problem.
Each particle keeps track of its coordinates
in the problem space , which are associated with the
best solution (evaluating value) it has achieved so
far. This value is called p best.
…… (20)
Another best value that is tracked by the
global version of the particle swarm optimizer is the
overall best value, and its location, obtained so far by
IV. OVERVIEW OF PARTICLE SWARM any particle in the group, is called G best.In PSO, each
OPTIMIZATION [17–19] particle moves in the search space with a Velocity
Particle swarm optimization (PSO) method. according to its own previous best solution and its
It is one of the optimization techniques and a kind of Group’s previous best solution. The velocity update
evolutionary computation technique. The method has in a PSO Consists of three parts ; namely
been found to be robust in solving problems featuring momentum, cognitive and social parts. The balance
nonlinearity and non differentiability, multiple among these parts determines the performance of a
optima, and high dimensionality through adaptation, PSO algorithm.
which is through adaptation, which is derived from
social- psychological theory. It is a population based
search algorithm
*The method is developed from research on swarm
such as fish schooling and bird flocking.
*It can be easily implemented, and has stable
convergence Characteristic with good computational
efficiency.
The PSO method is a member of wide
category of swarm intelligence methods for solving
the optimization problems. It is population based
search algorithm where each individual is referred to
as particle and represents a candidate solution. Each Fig:5 Position updates of particles in particle swarm
particle in PSO flies through the search space with an optimization Technique
adaptable velocity that is dynamically modified
according to its own flying experience and also the For example, the jth Particle is represented as xj= (xj.1,
flying experience of the other Particle. xj.2 ….. xj.n) in the g-dimensional space. The best
previous Position of the jth Particle is recorded and
The features of the searching procedure can be represented as best Pbest = (Pbestj.1, Pbestj.2 …….., Pbestj.1)
summarized as follows .The index of best among all of the particles in the
1) Initial positions of p best and g best are different. group is represented by particle G bestg The rate of the
However, using the different direction of p best and position change (velocity) for particle is represented
g best , all agents gradually get close to the global as Vj=( Vj.1,Vj.2,……………,V j.n). The modified
optimum. velocity and position of each particle can be
2) The modified value of the agent position is calculated using the current Velocity and the distance
continuous and the method can be applied to the from pbest j.g to g best g
continuous problem. How ever, the method can be
applied to the discrete problem using grids for XY V j,g(t+1) = W .v j.g +C*1rand()*(pbest j.g-xtj.g)
position and its velocity. C*2rand ()*(pbest j.g- xtj.g)
3) There are no inconsistency in searching …………….(21)
procedures even if continuous and discrete state
variables are utilized with continuous axes and grids X (t+1) j,g = X(t)j,g+ V(t+1)j,g ………………(22)
for XY positions and velocities. Namely, the method j = 1, 2... n
can be applied to mixed integer nonlinear g = 1, 2... m
optimization problems with continuous and discrete
state variables naturally and easily. Where
n number of particles in a group
m number of member in a particles
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Vol. 2, Issue 5, September- October 2012, pp.1817-1824
t pointer of iteration (generations) washout block serves as a high-pass filter, with the
Vt j.g velocity of particle j at iteration t time constant TW, high enough to allow signals
VG MIN ≤ VJ..Gt ≤ VGMAX; associated with oscillations in input signal to pass
W inertia weight factor unchanged. Without it steady changes in input would
C1,C2 acceleration constant modify the output. The damping torque contributed
Rand () , rand() random number between 0 and 1 by the TCSC can be considered to be in to two parts.
Xt j.g current position of particle j at iteration t ; The first part KP, which is referred as the direct
Pbest j Pbest o f particle j ; damping torque, is directly applied to the
gbest gbest of the group electromechanical oscillation loop of the generator.
The second part KQ and KV, named as the indirect
In the above procedures, the parameter Vmax damping torque, applies through the field channel of
determined the resolution, or fitness, with which the generator
regions be searched between the present position and
the target position. If Vmax is too high particles might In the above figure the parameters Kw, T1
fly past good solutions. If Vmax is too small particles and T2 are to be determined, Tw is summed to 20,
may not explore sufficiently beyond local solutions In T1=T3 and T2=T4.The input signal to the controller is
many experiences with PSO Vmax was often set at 10- the speed deviation and the output is the change in
20% of the dynamic range of the variable on each conduction angle. In steady state ∆σ=0, and Xe =Xeq–
dimension. XTCSC0 while during dynamic period the series
compensation is modulated for damping system
The constants c1 and c2 represent the oscillations , in this case Xe =Xeq –XTCSC .
weighting of the stochastic acceleration terms that
pull each particle Pbest and gbest positions. Low Where σ = σ+ ∆σ and ( σ =2( ∏-σ )), where
values allow particles to roam far from the target σ0 is the initial value of firing angle, and Xeq is total
regions before being tugged back. On the other hand, reactance of the system.
high values result in abrupt movement toward, or
past, target regions. Hence, the acceleration constants A.Objective function
c1 and c2 were often set to be 2.0 according to past TCSC controller is designed to minimize the
experiences Suitable selection of inertia weigh tin power System oscillations after a small or lager
(19) provides a balance between global and local disturbance so as to improve the stability. These
explorations, thus requiring less iteration on average oscillations are reflected in the deviation in the
to find a sufficiently optimal solution .As originally generator rotor speed (∆w). An integral time absolute
developed, often decreases linearly from about0.9 to error of the speed deviations is taken as the objective
0.4 during a run. In general, the inertia weight is set Function J, expressed as
according to the following equation: tsim
J= ∫(t, x) dt……….………… (24)
w=wmax- wmax - wmin ×iter t
itermax………............... (23) Where │∆w (t, x) │ is the absolute value of
Where itermax is the maximum number of the speed deviation for a set of controller parameters
iterations (generations), and iter is the current number x (K w ,T1, T2) and t is the time range of the
of iterations. simulation. With the variation of K w ,T 1,T2 , the
TCSC based controller parameters, J will also be
V. PROBLEM FORMULATION changed. For objective function calculation, the time-
The structure of TCSC controller domain simulation of the power system model is
implemented in stability control loop was discussed carried out for the simulation period. It is aimed to
earlier, fig. 5 show TCSC with stability control loop. minimize this objective function in order to improve
the system stability. The problem constraints are
TCSC controller parameter bounds; there the
optimization problem can be written as
Minimize J ……………...………….. (25)
Subject to
Fig:6 TCSC with stability control loop
K min w≤ K w≤ K max w
It consists of a gain block with gain KT, a T min 1 ≤ T 1 ≤ T max 1… …………...(26)
signal washout block and two-stage phase T min 2 ≤ T2 ≤ T max 2
compensation block as shown in figure .The phase
compensation block provides the appropriate phase- A particle swarm optimization is used to
lead characteristics to compensate for the phase lag solve the Optimization problem and then search for
between input and the output signals. The signal optimal parameters
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6. N.Srikanth, Atejasri / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1817-1824
tripped off. At t=0.5 sec
VI. SIMULATION AND RESULTS 2. Severe disturbance assuming three phase short
The objective function described by circuit Occur at bus 2 in all case TCSC is connected
equation (21) is evaluated using PSO toolbox given in first between bus(2-3) .and then between bus(3-4).
[21], for each individual by simulating SMIB shown
in fig. 4. a three phase short at bus bar 2 is A. small disturbance
considered and TCSC first is assumed to be Table (III) shows Eigen values of the tested
connected between bus (2-3), and then between system with and with out TCSC as well as the
bus(3-4) to find the best location n. Fig .6 shows the different locations of TCSC
flow chart o f PSO algorithm used in this work and Table (III): Eigen values analysis
table (I) illustrates the parameters used for this
algorithm. Table (II) shows the bounds for unknown stat Without TCSC TCSC
parameters of gain and time constants as well as the es TCSC Between Between
optimal parameter obtained from PSO algorithm. bus(2-3) bus(3-4)
δ -0.087+5.618 -2.4+4.1713 -0.4276+5.596
,w
Eq́ -0.167+0.393 -0.1737+0.373 -0.1682+0.396
It is clear from above table the system is stable in
both cases, in other words the proposed TCSC
controllers shift the,electro mechanical mode
eigenvalue to the left of the line (s=-2.4,-0.42766).in
S-plane which in turn enhances the system Stability .
B. severe disturbance
Case (I):
Now TCSC is supposed to be connected between bus
(2-3).The value of x L and x C was chosen as 0.068
and 0.034 pu respectively. A three phase short circuit
occur at t= 0.5 sec figures (8,9,10) shows rotor angle
and speed deviation and active power respectively
Fig: 7 flow chart of PSO algorithms with and without TCSC.
Table (I): PSO parameters
parameter Value
Swarm size 30
Max.gen 100
C 1C2 2.0,2.0
Wstrat ,wend 0.9,0.4
Table (II):Bounds &optimized parameters
Rotor angle (rad) Vs Time(sec)
parameter Kw T1=T3 T2=T4
Fig .8 Rotor angle
min 20 0.1 0.2
max 100 1 1
TCSC 66.5 0.1832 0.4018
connected
between
bus(2-3)
TCSC 80.67 0.1124 0.2523
connected
between
bus(3-4)
To assess the effectiveness of the proposed controller Rotor speed (rad) Vs Time(sec)
and best location the following cases are considered Fig .9 Rotor speed deviation
1. Small disturbance assuming that line 2(L2) is
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7. N.Srikanth, Atejasri / International Journal of Engineering Research and Applications
(IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue 5, September- October 2012, pp.1817-1824
Active power Pe (PU) Vs Time (sec) Active power Pe (PU) Vs Time(sec)
Fig 10. Active power Fig 13. Active power
No TCSC with TCSC No TCSC with TCSC
It is clear from above figures the proposed It is obvious from above figures damping
TCSC controller damp and suppresses the oscillations and suppressing .The oscillation in between when
and provides good damping characteristics by TCSC is connected between Bus (3-4).
stabilizing system much faster, which in turn
enhances system stability. VII. CONCLUSION
In this paper the impact of TCSC on
Case (II): enhancing power system stability was investigated for
Now TCSC is supposed to be connected small and severe disturbances. Optimal parameters
between bus (3-4),the value of x Land x C was chosen and different locations of TCSC were evaluated. The
as 0.068 and 0.034 pu respectively . A three phase problem is formulated as optimization problem to
short circuit occur at t= 0.5 sec figures (11, 12,13) minimize the rotor angle deviation and PSO (
shows rotor angle and speed deviation , and power particle swarm optimization) techniques employed to
respectively with and without TCSC. find out the optimal parameters and allocation of
TCSC, under different test cases. The proposed
controller and design approach testes on SIMB using
MATLAB environment. The non-linear simulation
and eigenvalue analysis results show effectiveness of
the proposed controller to enhance power system
stability and best allocation n of TCSC.
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