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.
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.
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.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
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.
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.
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.
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.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
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.
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.
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.
Power Quality Enhancement in Power Distribution system using Artificial intel...sundar balan
Dynamic voltage Restorer
Artificial intelligence based Dynamic voltage restorer
DVR
Artificial neural network based DVR dynamic voltage restorer
Harmonics voltage harmonics voltage sag voltage swell
Power Quality Enhancement in Power Distribution system using Artificial intelligence based Dynamic Voltage Restorer
International Refereed Journal of Engineering and Science (IRJES)irjes
The core of the vision IRJES is to disseminate new knowledge and technology for the benefit of all, ranging from academic research and professional communities to industry professionals in a range of topics in computer science and engineering. It also provides a place for high-caliber researchers, practitioners and PhD students to present ongoing research and development in these areas.
Simulation of D-STATCOM to study Voltage Stability in Distribution systemijsrd.com
This paper presents the simulation of D-statcom to understand the improvement of voltage stability [1] of distribution system. The power circuits of the D-STATCOM and distribution networks are made up of simpower system blocks, while the control circuits made with the simulink blocks The STATCOM is applied to regulate transmission voltage to allow greater power flow in a voltage limited transmission network, in the same manner as a static var compensator (SVC), the STATCOM has further potential by giving an inherently faster response and greater output to a system with depressed voltage and offers improved quality of supply. The main applications of the STATCOM are; Distribution STATCOM (D-STATCOM) exhibits high speed control of reactive power to provide voltage stabilization and other type of system control. The DSTATCOM protects the utility transmission or distribution system from voltage sag and /or flicker caused by rapidly varying reactive current demand. During the transient conditions the D-STATCOM provides leading or lagging reactive power to active system stability, power factor correction and load balancing.
The Direct Power Contro; has many advantages like it avoids the usage of integration of PWM voltages which leads to stable operation even at zero rotor frequency, it is position sensor less and hence will not depend on machine parameters like stator or rotor resistance. In case of network unbalance, if the system is operated with constant active and reactive powers, it leads to oscillations in the electromagnetic torque and currents exchange with the grid will become non- sinusoidal, which is not good for the system as it increases the mechanical stress. In this paper, both the rotor connected converter and grid connected converter are fed with DPC strategy along with that a Torque Oscillations Cancellation scheme is applied to RSC and Proportional Integral control based power references generation strategy without calculating the sequence components and with elimination of DC bus voltage oscillations is applied to stator-side converter in order to achieve non-oscillating torque accompanied by quality improved current exchange with the grid. The simulation results of Doubly Fed Induction Generator with and without fault clearly shows that the performance of the proposed scheme is validated.
Voltage Sag and Swell Identification Using FFT Analysis and Mitigation with DVRIOSRJEEE
- Power quality issues like voltage sag, swell, harmonics and transients can affect the power system performance. Voltage sag and swell are now-a-days treated to reduce power quality issues by power engineers. A small variation in voltage can badly affect the operation of power system and connected loads as well. This paper presents the voltage sag and voltage swell identification using FFT analysis. The paper also presents the mitigation for identified voltage sag and swells issues addressed with DVR. DVR consists of a voltage source converter and is controlled with d-q theory which is simple producing reference signals and gate pulses for switches of DVR. The proposed concept was simulated using MATLAB/SIMULINK software and results were presented for identification and mitigation. FFT analyses for identification of voltage sags and swell existence in different phases of power system network were shown. Mitigation of voltage sag and swell with DVR was also shown with results
Comparison of Dynamic Stability Response of A SMIB with PI and Fuzzy Controll...ijeei-iaes
Consumer utilities are non –linear in nature. This injects increased flow of current and reduced voltage with distortions which cause adverse effect on the stability of consumer utilities. To overcome this problem we are using a modern Flexible Alternating Current Transmission System controller i.e. distributed power flow controller (DPFC). This controller is similar to UPFC, which can be installed in a transmission line between the two electrical areas. In DPFC, instead of the common Dc link capacitor three single phase converters are used. In this paper we are concentrating on system stability (oscillation damping). For analyzing the stability of a single machine infinite bus system (SMIB) we have used PI controlled Distributed Power Flow Controller (DPFC) and Fuzzy controlled DPFC. All these models are simulated using MATLAB/SIMULINK. Simulation results shows Fuzzy controlled DPFC are better than PI controlled DPFC. The significance of the results are better stability and constant power supply.
Compensation of Single-Phase and Three-Phase Voltage Sag and Swell Using Dyna...IJAPEJOURNAL
DVR is a equipment which was connected in series and adjusting the loading voltage by feeding the voltage in system. The first installation was in 1996. usually DVR installed between sensitive loads feeder and source in distribution system .The main duty, fast support load voltage (by fast detection algorithm) during disturbance to avoid any disconnection. in this paper approaches to compensate for voltage sag and swell as a common disturbance in voltage transmission and distribution networks is presented. A dynamic voltage restorer based on the dq0 algorithm for three-phase and dynamic voltage restorer based on the average detection method for single-phase are discussed, also in this paper we compare the two methods used to compensate the single-phase and three-phase process. result of three-phase and single-phase voltage sag and swell simulation has been presented by MATLAB/SIMULINK.
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.
This paper presents modular multilevel converter (MMC) with circulating current control which provides an improved balanced capacitors voltages. The control is achieved by employing compensation techniques in the external and internal controls of the MMC based static compensator (STATCOM). Performance variations arise during STATCOM non-ideal operation with grid externally and during capacitors voltage transients due to charging and discharging within the MMC that result in the emergence of a voltage disturbance. The proportional integral (PI) controller is usually employed in the external and internal controls for a fast response and reactive current control. In this paper, the performance of the PI controller is improved using voltage compensation in the external control and virtual impedance in the capacitor voltage control within a five-level MMC. The proposed control minimizes the variations in the STATCOM operations with the grid and within the MMC to provide an enhanced overall system response.
Comparative analysis of improved high performance direct power control of thr...eSAT Journals
Abstract
Direct Power Control with switching table control produces irregular ripples and variable switching frequency. In the improved DPC of PWM rectifiers using fractional control period of the active voltage vector and the rest period for the null vector not only makes it line side inductance independent of the circuit and is very simple to implement due to the duty cycle concept. By simulation it is identified that the level of distortion as well as regulation of the DC link voltage with control of power factor improves the overall performance of the drive. The improved Direct Power Control (DPC) PWM methodology is comprehensively analyzed and studied for three phase rectifiers and compared with the classical DPC with PLL. The MATLAB simulations shows the effectiveness in obtaining unity power factor and constant dc link voltage control. The power ripples are considerably reduced and input sinusoidal grid currents are obtained.
Keywords— Direct power control, instantaneous active and reactive power, pulse width modulation, duty cycle, dc link control, unity power factor
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.
Sag mitigation in distribution system by using Dynamic voltage Restorer (DVR)IJERA Editor
Power quality is most important concern in the current age. It’s now a day’s necessary with the refined devices, where performance is very perceptive to the quality of power supply. Power quality crisis is an incidence manifest as a typical voltage, current or frequency that results in a failure of end use equipments. One of the major crises dealt here is the power sag. Perceptive industrial loads and distribution networks suffer from different types of service interruptions and outages which results in a major financial loss. To improve the power quality, custom power-devices are used. The device considered in this work is Dynamic Voltage Restorer. This paper shows modelling, analysis and simulation of a DVR test systems using MATLAB.
I have considered single line to ground fault for linear load. The role of DVR is to “compensate load voltage” is examined during the different fault conditions like voltage sag, single phase to ground faults.
Mitigation of Fault in the Distribution System by using Flexible Distributed ...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.
10 Insightful Quotes On Designing A Better Customer ExperienceYuan Wang
In an ever-changing landscape of one digital disruption after another, companies and organisations are looking for new ways to understand their target markets and engage them better. Increasingly they invest in user experience (UX) and customer experience design (CX) capabilities by working with a specialist UX agency or developing their own UX lab. Some UX practitioners are touting leaner and faster ways of developing customer-centric products and services, via methodologies such as guerilla research, rapid prototyping and Agile UX. Others seek innovation and fulfilment by spending more time in research, being more inclusive, and designing for social goods.
Experience is more than just an interface. It is a relationship, as well as a series of touch points between your brand and your customer. Here are our top 10 highlights and takeaways from the recent UX Australia conference to help you transform your customer experience design.
For full article, continue reading at https://yump.com.au/10-ways-supercharge-customer-experience-design/
http://inarocket.com
Learn BEM fundamentals as fast as possible. What is BEM (Block, element, modifier), BEM syntax, how it works with a real example, etc.
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.
Power Quality Enhancement in Power Distribution system using Artificial intel...sundar balan
Dynamic voltage Restorer
Artificial intelligence based Dynamic voltage restorer
DVR
Artificial neural network based DVR dynamic voltage restorer
Harmonics voltage harmonics voltage sag voltage swell
Power Quality Enhancement in Power Distribution system using Artificial intelligence based Dynamic Voltage Restorer
International Refereed Journal of Engineering and Science (IRJES)irjes
The core of the vision IRJES is to disseminate new knowledge and technology for the benefit of all, ranging from academic research and professional communities to industry professionals in a range of topics in computer science and engineering. It also provides a place for high-caliber researchers, practitioners and PhD students to present ongoing research and development in these areas.
Simulation of D-STATCOM to study Voltage Stability in Distribution systemijsrd.com
This paper presents the simulation of D-statcom to understand the improvement of voltage stability [1] of distribution system. The power circuits of the D-STATCOM and distribution networks are made up of simpower system blocks, while the control circuits made with the simulink blocks The STATCOM is applied to regulate transmission voltage to allow greater power flow in a voltage limited transmission network, in the same manner as a static var compensator (SVC), the STATCOM has further potential by giving an inherently faster response and greater output to a system with depressed voltage and offers improved quality of supply. The main applications of the STATCOM are; Distribution STATCOM (D-STATCOM) exhibits high speed control of reactive power to provide voltage stabilization and other type of system control. The DSTATCOM protects the utility transmission or distribution system from voltage sag and /or flicker caused by rapidly varying reactive current demand. During the transient conditions the D-STATCOM provides leading or lagging reactive power to active system stability, power factor correction and load balancing.
The Direct Power Contro; has many advantages like it avoids the usage of integration of PWM voltages which leads to stable operation even at zero rotor frequency, it is position sensor less and hence will not depend on machine parameters like stator or rotor resistance. In case of network unbalance, if the system is operated with constant active and reactive powers, it leads to oscillations in the electromagnetic torque and currents exchange with the grid will become non- sinusoidal, which is not good for the system as it increases the mechanical stress. In this paper, both the rotor connected converter and grid connected converter are fed with DPC strategy along with that a Torque Oscillations Cancellation scheme is applied to RSC and Proportional Integral control based power references generation strategy without calculating the sequence components and with elimination of DC bus voltage oscillations is applied to stator-side converter in order to achieve non-oscillating torque accompanied by quality improved current exchange with the grid. The simulation results of Doubly Fed Induction Generator with and without fault clearly shows that the performance of the proposed scheme is validated.
Voltage Sag and Swell Identification Using FFT Analysis and Mitigation with DVRIOSRJEEE
- Power quality issues like voltage sag, swell, harmonics and transients can affect the power system performance. Voltage sag and swell are now-a-days treated to reduce power quality issues by power engineers. A small variation in voltage can badly affect the operation of power system and connected loads as well. This paper presents the voltage sag and voltage swell identification using FFT analysis. The paper also presents the mitigation for identified voltage sag and swells issues addressed with DVR. DVR consists of a voltage source converter and is controlled with d-q theory which is simple producing reference signals and gate pulses for switches of DVR. The proposed concept was simulated using MATLAB/SIMULINK software and results were presented for identification and mitigation. FFT analyses for identification of voltage sags and swell existence in different phases of power system network were shown. Mitigation of voltage sag and swell with DVR was also shown with results
Comparison of Dynamic Stability Response of A SMIB with PI and Fuzzy Controll...ijeei-iaes
Consumer utilities are non –linear in nature. This injects increased flow of current and reduced voltage with distortions which cause adverse effect on the stability of consumer utilities. To overcome this problem we are using a modern Flexible Alternating Current Transmission System controller i.e. distributed power flow controller (DPFC). This controller is similar to UPFC, which can be installed in a transmission line between the two electrical areas. In DPFC, instead of the common Dc link capacitor three single phase converters are used. In this paper we are concentrating on system stability (oscillation damping). For analyzing the stability of a single machine infinite bus system (SMIB) we have used PI controlled Distributed Power Flow Controller (DPFC) and Fuzzy controlled DPFC. All these models are simulated using MATLAB/SIMULINK. Simulation results shows Fuzzy controlled DPFC are better than PI controlled DPFC. The significance of the results are better stability and constant power supply.
Compensation of Single-Phase and Three-Phase Voltage Sag and Swell Using Dyna...IJAPEJOURNAL
DVR is a equipment which was connected in series and adjusting the loading voltage by feeding the voltage in system. The first installation was in 1996. usually DVR installed between sensitive loads feeder and source in distribution system .The main duty, fast support load voltage (by fast detection algorithm) during disturbance to avoid any disconnection. in this paper approaches to compensate for voltage sag and swell as a common disturbance in voltage transmission and distribution networks is presented. A dynamic voltage restorer based on the dq0 algorithm for three-phase and dynamic voltage restorer based on the average detection method for single-phase are discussed, also in this paper we compare the two methods used to compensate the single-phase and three-phase process. result of three-phase and single-phase voltage sag and swell simulation has been presented by MATLAB/SIMULINK.
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.
This paper presents modular multilevel converter (MMC) with circulating current control which provides an improved balanced capacitors voltages. The control is achieved by employing compensation techniques in the external and internal controls of the MMC based static compensator (STATCOM). Performance variations arise during STATCOM non-ideal operation with grid externally and during capacitors voltage transients due to charging and discharging within the MMC that result in the emergence of a voltage disturbance. The proportional integral (PI) controller is usually employed in the external and internal controls for a fast response and reactive current control. In this paper, the performance of the PI controller is improved using voltage compensation in the external control and virtual impedance in the capacitor voltage control within a five-level MMC. The proposed control minimizes the variations in the STATCOM operations with the grid and within the MMC to provide an enhanced overall system response.
Comparative analysis of improved high performance direct power control of thr...eSAT Journals
Abstract
Direct Power Control with switching table control produces irregular ripples and variable switching frequency. In the improved DPC of PWM rectifiers using fractional control period of the active voltage vector and the rest period for the null vector not only makes it line side inductance independent of the circuit and is very simple to implement due to the duty cycle concept. By simulation it is identified that the level of distortion as well as regulation of the DC link voltage with control of power factor improves the overall performance of the drive. The improved Direct Power Control (DPC) PWM methodology is comprehensively analyzed and studied for three phase rectifiers and compared with the classical DPC with PLL. The MATLAB simulations shows the effectiveness in obtaining unity power factor and constant dc link voltage control. The power ripples are considerably reduced and input sinusoidal grid currents are obtained.
Keywords— Direct power control, instantaneous active and reactive power, pulse width modulation, duty cycle, dc link control, unity power factor
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.
Sag mitigation in distribution system by using Dynamic voltage Restorer (DVR)IJERA Editor
Power quality is most important concern in the current age. It’s now a day’s necessary with the refined devices, where performance is very perceptive to the quality of power supply. Power quality crisis is an incidence manifest as a typical voltage, current or frequency that results in a failure of end use equipments. One of the major crises dealt here is the power sag. Perceptive industrial loads and distribution networks suffer from different types of service interruptions and outages which results in a major financial loss. To improve the power quality, custom power-devices are used. The device considered in this work is Dynamic Voltage Restorer. This paper shows modelling, analysis and simulation of a DVR test systems using MATLAB.
I have considered single line to ground fault for linear load. The role of DVR is to “compensate load voltage” is examined during the different fault conditions like voltage sag, single phase to ground faults.
Mitigation of Fault in the Distribution System by using Flexible Distributed ...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.
10 Insightful Quotes On Designing A Better Customer ExperienceYuan Wang
In an ever-changing landscape of one digital disruption after another, companies and organisations are looking for new ways to understand their target markets and engage them better. Increasingly they invest in user experience (UX) and customer experience design (CX) capabilities by working with a specialist UX agency or developing their own UX lab. Some UX practitioners are touting leaner and faster ways of developing customer-centric products and services, via methodologies such as guerilla research, rapid prototyping and Agile UX. Others seek innovation and fulfilment by spending more time in research, being more inclusive, and designing for social goods.
Experience is more than just an interface. It is a relationship, as well as a series of touch points between your brand and your customer. Here are our top 10 highlights and takeaways from the recent UX Australia conference to help you transform your customer experience design.
For full article, continue reading at https://yump.com.au/10-ways-supercharge-customer-experience-design/
http://inarocket.com
Learn BEM fundamentals as fast as possible. What is BEM (Block, element, modifier), BEM syntax, how it works with a real example, etc.
How to Build a Dynamic Social Media PlanPost Planner
Stop guessing and wasting your time on networks and strategies that don’t work!
Join Rebekah Radice and Katie Lance to learn how to optimize your social networks, the best kept secrets for hot content, top time management tools, and much more!
Watch the replay here: bit.ly/socialmedia-plan
Lightning Talk #9: How UX and Data Storytelling Can Shape Policy by Mika Aldabaux singapore
How can we take UX and Data Storytelling out of the tech context and use them to change the way government behaves?
Showcasing the truth is the highest goal of data storytelling. Because the design of a chart can affect the interpretation of data in a major way, one must wield visual tools with care and deliberation. Using quantitative facts to evoke an emotional response is best achieved with the combination of UX and data storytelling.
Content personalisation is becoming more prevalent. A site, it's content and/or it's products, change dynamically according to the specific needs of the user. SEO needs to ensure we do not fall behind of this trend.
Succession “Losers”: What Happens to Executives Passed Over for the CEO Job?
By David F. Larcker, Stephen A. Miles, and Brian Tayan
Stanford Closer Look Series
Overview:
Shareholders pay considerable attention to the choice of executive selected as the new CEO whenever a change in leadership takes place. However, without an inside look at the leading candidates to assume the CEO role, it is difficult for shareholders to tell whether the board has made the correct choice. In this Closer Look, we examine CEO succession events among the largest 100 companies over a ten-year period to determine what happens to the executives who were not selected (i.e., the “succession losers”) and how they perform relative to those who were selected (the “succession winners”).
We ask:
• Are the executives selected for the CEO role really better than those passed over?
• What are the implications for understanding the labor market for executive talent?
• Are differences in performance due to operating conditions or quality of available talent?
• Are boards better at identifying CEO talent than other research generally suggests?
Each technological age has been marked by a shift in how the industrial platform enables companies to rethink their business processes and create wealth. In the talk I argue that we are limiting our view of what this next industrial/digital age can offer because of how we read, measure and through that perceive the world (how we cherry pick data). Companies are locked in metrics and quantitative measures, data that can fit into a spreadsheet. And by that they see the digital transformation merely as an efficiency tool to the fossil fuel age. But we need to stretch further…
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.
A Versatile Control Scheme For Dynamic Voltage Restorer To Limit Downstream F...IJERA Editor
The Dynamic Voltage Restorer (DVR) is a custom power device utilized to counteract voltage sags. It injects
controlled three-phase ac voltages in series with the supply voltage, subsequent to voltage sag, to enhance
voltage quality by adjusting the voltage magnitude, wave shape, and phase angle. The DVR is conventionally
bypassed during a downstream fault to prevent potential adverse impacts on the fault and to protect the DVR
components against the fault current. This paper proposes an augmented control strategy for the DVR that
provides:1) voltage-sag compensation under balanced and unbalanced conditions and 2) a fault current
interruption (FCI) function. This paper introduces and evaluates an auxiliary control strategy for downstream
fault current interruption in a radial distribution line by means of a dynamic voltage restorer (DVR). The
proposed controller supplements the voltage-sag compensation control of the DVR. It does not require phaselocked
loop and independently controls the magnitude and phase angle of the injected voltage for each phase.
Fast least error squares digital filters are used to estimate the magnitude and phase of the measured voltages and
effectively reduce the impacts of noise, harmonics, and disturbances on the estimated phasor parameters, and
this enables effective fault current interrupting even under arcing fault conditions. The performance of the DVR
for fault current interruption is analyzed by using MATLAB/SIMULINK software.
SRF CONTROLLED DVR FOR COMPENSATION OF BALANCED AND UNBALANCED VOLTAGE DISTUR...IAEME Publication
The growth of power electronictechnology in the field of electric power sector has caused a greater awarenesson the power quality of distribution systems. With the re-structuring of powersystems and with shifting trend towards distributed and dispersed generation,the issue of power quality is going to take newer dimensions. The presentresearch is to identify the prominent concerns in this area and hence themeasures that can enhance the quality of power. This paper investigates theproblems of voltage sag, swell and its severe impact on nonlinear loads,sensitive loads.
Power Quality Enhancement through Dynamic Voltage Restorer using SRF Theory f...IJERD Editor
Power quality is certainly a major concern in the present era, it becomes especially important with
the introduction of sophisticated devices, whose performance is very sensitive to the quality of power supply.
Voltage sag is one of the severe power quality problems. This report addresses all the different aspects related to
voltage sag problem, such as its types, consequences and mitigation.
At present, a wide range of very flexible controllers, which capitalize on newly available power electronics
components, are emerging for custom power applications. Among these, the distribution static compensator (DSTATCOM)
and the dynamic voltage restorer (DVR) are most effective devices, both of them based on the
VSC principle.
Performance Assessment of IPFC with IDVR for Two Feeder Transmission systemsIJMER
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.
DVR with Artificial Intelligent Controller for Voltage Sag MitigationMohamed Khaleeel
This paper concludes that DVR is an effective device to compensate the voltage sag in power distribution systems. In term of DVR applications, although Mamdani-type and Sugeno-type share the same functions and rules, there are some distinctions between them.
Dynamic voltage restorer (DVR) is a device that can compensate harmonic, voltage sag and voltage swell condition that exists in a three-phase system. Other than that, DVR can also be used to enhance the energy efficiency or energy saving by reducing excessive amount of incoming power via the reduction incoming voltage at allowable limit. The DVR can inject the required voltage in the system so that the interruption of supply voltage can be compensated. The compensation of voltage supply interruption is improved based on the hysteresis voltage output of controller used in the DVR to detect the difference between reference voltage and disrupted voltage. The hysteresis voltage control mainly controlled by relays switching so that the signal can be sent to IGBT switches controller. The hysteresis voltage control and unipolar SPWM is supplied to control the IGBT switches by the DC supply for voltage interruption compensation. The unipolar SPWM technique converts the DC supply voltage into AC supplied voltage, thus making the DVR injection become easier to inject the AC voltage into the system to compensate voltage sag and voltage swell.
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.
Utilization of DVR with FLC to Inject Voltage in a Transmission LineIJMER
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.
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
Modeling and simulation of dynamic voltage restorer for voltage sag mitigatio...IJRRR
Abstract- Power quality deals with utilization of electric energy from the distribution system successfully without interference or interruption. Various factors like interruption in power supply, under voltage, over voltage, unbalanced voltage or current, harmonic distortion, flickering voltage, voltage fluctuation voltage sag etc. result in poor power quality. These power quality related problems can be solved with the help of various custom power devices. Voltage sags are considered to be the most common type of disturbances in the field based on current power disturbances studies. Their impact on sensitive loads is rigorous. The impact ranges from load disruptions to financial losses. In spite of the technical advances in electronics, there are some pieces of equipment that are so sensitive that they are unable to withstand voltage sags. There are many varies methods to mitigate voltage sags, but a Custom Power Supply device is considered to be the most efficient method. This dissertation is the study of Dynamic Voltage Restorer (DVR) which is the most efficient and effective device to protect sensitive equipment against voltage sags. It has low cost, smaller size and it has dynamic response to the disturbance.
Keywords- Voltage sag, DVR, power system, mitigation
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
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
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Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
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Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
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Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
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All of this illustrated with link prediction over knowledge graphs, but the argument is general.
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Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
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Your campaign sent to target colleagues for approval
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Speakers:
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JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
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https://www.rttsweb.com/jmeter-integration-webinar
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
When stars align: studies in data quality, knowledge graphs, and machine lear...
Km3518071813
1. P. Harichandana et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 5, Sep-Oct 2013, pp.1807-1813
RESEARCH ARTICLE
www.ijera.com
OPEN ACCESS
Improvement of DVR Performance Using Fast and Effective
Control Scheme under Various Loads
P. Harichandana, M. Tech Scholar*, Madhavi Sunkara, M. Tech**
*(Department of Electrical and Electronics Engineering, GEC Gudlavalleru, Andhra Pradesh, India)
** (Department of Electrical and Electronics Engineering, GEC Gudlavalleru, Andhra Pradesh, India)
ABSTRACT
The dynamic voltage restorer (DVR) has become popular as a cost effective and efficient solution for the
protection of sensitive loads from voltage sags. This paper reports a novel control scheme for DVR to achieve
fast response and effective sag compensation capabilities. The DVR, which is placed in series with sensitive
load, must be able to respond quickly to voltage sag if end user’s of sensitive equipment are to experience no
voltage fluctuations. But the proposed control scheme is controls the magnitude and phase angle of the injected
voltage for each phase separately. Fast least error squares digital filters are used to estimate the magnitude and
phase of the measured voltages. The utilized least error squares estimated filters considerably reduce the effects
of noise, harmonics and disturbances on the estimated phasor parameters. This enables the DVR to detect and
compensate voltage sags accurately, under linear and non linear load conditions. The proposed control system
does not need any phase locked loops. It also effectively limits the magnitude of the modulating signals to
prevent over-modulation. Both sides, separately controlling the injected voltage in phase enable the DVR to
restore load voltage in short time interval (5ms) with zero steady state. Results of the simulation studies in the
MATLAB/SIMULINK software environment indicate that the proposed control scheme performs satisfactorily
under linear, non linear loads and BLDC motor drive.
Keywords – BLDC motor, DVR, Least error square digital filters, voltage sag.
I.
INTRODUCTION
Electric power quality is capacity of an
electric power system to supply electric energy of a
load in an acceptable quality. Power distribution
system should provide with an uninterrupted flow of
energy at smooth sinusoidal voltage at the contracted
magnitude level and frequency to their customers.
Power systems especially distribution systems, have
numerous non linear loads, which significantly affect
the quality of power. Apart from non linear loads like
capacitor switching, motor starting and unusual faults
could also inflict power quality problems. Many
problems can result from poor power quality (PQ),
especially in today’s complex power system, such as
the false operation of modern control systems. Voltage
sag is an important PQ problem because of sensitive
loads growth. Worldwide experience has showed that
short circuit faults are the main origin of voltage sag;
therefore there is a loss of voltage quality [1]-[3].
Voltage sag is defined as a sudden reduction
in supply voltage to between 90% and 10% of the
nominal value, followed by a recovery after a short
interval (the standard duration of sag is between 10
milliseconds and 1 minute). The most common
compensator for voltage sag is the dynamic voltage
restorer (DVR). The basic operation of the DVR is
based on injection of a compensation voltage with
required magnitude, phase angle and frequency in
series with the sensitive electric distribution feeder.
www.ijera.com
A dynamic voltage restorer (DVR) can eliminate most
sags and minimize the risk of load tripping during sags
[2], [3]-[5]. It injects appropriate three phase ac
voltages in series with the supply, when voltage sag is
detected./Considering the shortcomings of the
preceding methods, a fast and effective control
scheme for the DVR is proposed in this paper. Three
identical control systems are used to control the
injected voltage in each phase independently. Three
single phase H-bridge VSIs are utilized to generate
sinusoidal voltages. The proposed multi loop control
system [1], [3], [9], [13] is comprised of an outer
phasor-based load voltage control system and an inner
injected voltage-control system. The phasor
parameters of the measured supply and load voltages
are estimated by using least error squares (LES) filters
[15] in a short time interval (5 ms). LES filters are
widely used for fast and reliable phasor parameter
estimation in digital protection systems. On the other
hand, the inner injected voltage-control system is
utilized for damping the transient resonant oscillations
caused by the harmonic filter to improve the dynamic
response and stability of the DVR.
The performance of the proposed control
scheme is evaluated by using MATLAB/SIMULINK
software. The study results indicate that the proposed
control strategy has the following advantages:
It regulates the load voltage negative- and zerosequence components as well as the positivesequence component in a considerably short time
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2. P. Harichandana et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 5, Sep-Oct 2013, pp.1807-1813
period (5 ms), with zero steady state error and
without phase jump.
The proposed DVR system can be used in both
four wired and three wired distribution systems,
or even in a single phase configuration.
The proposed method to limit the magnitude of
the modulating signals without distorting the
injected voltage wave-shape.
The utilized LES filters the effects of noise,
harmonics and disturbances on the estimated
parameters. This results in accurate sag detection
and compensation under nonlinear load
conditions.
The proposed control strategy does not need
phase locked loops, because the phase angles of
the measured voltages are estimated by using the
LES filters in 5 ms.
Due to the inherent characteristics of the proposed
control scheme, there is no need for utilizing
complicated controllers. Therefore, simple PI and
proportional controllers are utilized in this paper.
II.
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Widely used in present DVR control is the so-called in
phase voltage injection technique where the load
voltage V2 is assumed to be in-phase with the pre-sag
voltage. As the DVR is required to inject active power
into the distribution line during the period of
compensation, the capacity of the energy storage unit
can become a limiting factor in the disturbance
compensation process. In particular, if capacitors are
used as energy storage, the DC-link voltage will
decrease with the dwindling storage energy during
compensation.
Dynamic Voltage Restorer
Dynamic voltage restorer was originally
proposed to compensate for voltage disturbances on
distribution systems. A typical DVR scheme is shown
in Fig. 1. The restoration is based on injecting AC
voltages in series with the incoming three-phase
network, the purpose of which is to improve voltage
quality by adjustment in voltage magnitude, waveshape, and phase shift. As shown in Fig. 1, the DVR
essentially consists of a series-connected injection
transformer Ti, a voltage-source inverter (VSI), a
harmonic filter, and an energy storage device [4], [13].
Meanwhile, a parallel switch is used to bypass and
protect the DVR, when a downstream fault is detected
[14], [15]. As shown in Fig. 1, the line-side harmonic
filter topology [11] consists of the leakage inductance
of the injection transformer and the filter capacitor.
Meanwhile, denotes the dc-link capacitor.
The series injected voltage of the DVR,
Vdvr, is synthesized by modulating pulse widths of
the inverter-bridge switches. The injection of an
appropriate Vdvr in the face of an up-stream voltage
disturbance requires a certain amount of real and
reactive power supply from the DVR. The reactive
power requirement is generated by the inverter.
Fig. 1: schematic diagram of the DVR with line side
harmonic filter
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Fig. 2: Vector Diagram of Voltage Injection Method
The
corresponding
phasor
diagram
describing the electrical conditions during voltage sag
is depicted, where only the affected phase is shown for
clarity. Let the voltage quantities Il, φ, δ and α
represent the load current, load power factor angle,
supply voltage phase angle and load voltage advance
angle respectively. Although there is a phase
advancement of α in the load voltage with respect to
the pre-sag voltage in Fig. 2, only in-phase
compensation where the injected voltage is in phase
with the supply voltage (α = δ) is considered. The
block diagram of the proposed DVR control system
for one phase is depicted in Fig. 2. Assume that the
fundamental frequency components of the supply
(grid-side) and load phase voltages are defined by (1)
and (2), respectively.
As shown in Fig. 2, a multi-loop control system is
used to improve the transient and steady-state
responses of the DVR. The proposed control system is
comprised of an outer phasor based load voltage
control system and an inner injected voltage control
system. The former generates a reference signal for
the latter.
The presag phasor of the supply voltage is denoted by
.
is assumed to be equal to the
nominal phase voltage rms value. Meanwhile,
is
determined by using a phase freezer unit.
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3. P. Harichandana et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 5, Sep-Oct 2013, pp.1807-1813
III.
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Proposed DVR Control Scheme
Fig. 3: Block diagram of the DVR control scheme for each phase
The function of the phase freezer is to fix
(Freeze) the presag phase angle of the supply voltage,
to be used as the reference phase angle of the load
voltage, as described in [1], [6], and [9]. The sag
detection unit enables the phase freezer unit when
becomes less than 0.95 p.u. of the nominal phase
voltage (during voltage sags). It must be noted that
the proposed control scheme does not need a PLL,
because the voltage phase angle is estimated by using
the LES filter.
3.1 Load Voltage control system
The phasor-based load voltage-control
system restores the fundamental frequency
component of the load voltage to its presag
conditions. Based on the presag compensation
method, the voltage phasor, which must be injected
by the DVR, is the complex difference between the
supply voltage phasor and the presage supply voltage
phasor, as shown in the vector diagram of Fig. 4. This
phasor (the feed forward-injected voltage phasor
) is calculated by the phasor
subtraction unit, shown in Fig. 4 according to (3) and
(4). The coefficient in (3) is 1 when
; otherwise it is -1
(3)
(4)
Two PI controllers ( and ) are used to
eliminate the steady state errors of the magnitude and
phase angle of the load voltage, respectively. These
controllers compensate dc error signals. Therefore,
their parameters are set simply by a try-and-error
method in order to achieve a fast response with zero
steady-state error and without an observable
overshoot.
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Fig. 4: Vector diagram of the phasor subtraction unit
The outputs of the PI controllers
and
are added to the outputs of the feed-forward
loop
and
to achieve the overall output
phasor of the outer voltage-control loop as
(5)
3.2 Injected Voltage Control System
Voltage sags could be effectively
compensated if the output of the phasor-based control
system
was fed to the sinusoidal pulse width
modulation (SPWM) unit. However, the harmonic
filter resonances could not be eliminated under these
conditions. Therefore, in order to improve the
stability and dynamic response of the DVR, an
injected voltage controller and a filter capacitor
current controller are utilized, which attenuate the
harmonic filter resonances.
The generated reference signal for the
injected voltage
is compared with the measured
injected voltage , and the error is fed to the voltage
controller. The utilized voltage controller
is a
controller with the proportional gain of . As shown
in Fig. 3, the output of the voltage controller
is
the reference signal for the filter capacitor current
control loop. It is compared with the measured
capacitor current and the error is fed to the current
controller
, which is a P controller with the gain
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4. P. Harichandana et al Int. Journal of Engineering Research and Application
ISSN : 2248-9622, Vol. 3, Issue 5, Sep-Oct 2013, pp.1807-1813
A large
means high amplification of the
DVR filter resonance, which will affect the system
stability. Thus, the desirable transient response (fast
response) of the DVR is provided by using a feedforward loop, and low proportional gain is utilized as
the voltage controller. On the other hand, a large
will damp the harmonic filter resonance more
effectively, but
is always limited due to practical
considerations, such as amplifications of capacitor
current noise, measurement noise, and dc offset [12].
Therefore, the lowest value of the proportional gain,
which still damps the resonances effectively, is
utilized as the current controller. The output of the
current controller is added to the feed-forward
voltage to derive the control (modulating) signal for
the PWM generator of the inverter.
IV.
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Fig.6: (a) Supply Voltage. (b) Estimated RMS supply
Voltage of depressed phase. (c) Injected Voltage
magnitudes for the depressed voltage.
Modeling and Simulation Results
4.1 Sag Compensation under Linear Loads
The performance of the proposed DVR
control scheme during voltage sags caused by single
line-to-ground (SLG) and line-to-line (LL) faults
under linear load conditions is investigated in this
subsection. The DVR is protected by using a 10-kVA
linear load with a power factor of 0.9.
4.1.1 Single Line-to-Ground Fault
Fig.7: (a) Load Voltage. (b) Injected Voltages for the
depressed Phase. (c) DC-Link Voltage.
4.1.2 Line-to-Line Fault
Fig.5: Simulation model of sag compensation during
SLG fault under Linear Load
Modeling circuit and results of simulations
for SLG fault with a fault resistance of 0.5Ω are
shown in Figs. 5 and 6. The short-circuit, taking
place on 30% of the length of the parallel
transmission line connected to starts at 0.08sec and is
cleared at 0.16sec. Fig. 7(a)–(c) depicts the injected
voltages for the depressed phases, the restored load
voltages, and DC-Link voltage.
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Fig.8: (a) Supply Voltage. (b) Estimated RMS supply
Voltage of depressed phases. (c) Injected Voltage
magnitudes for the depressed voltage.
The results of simulations for voltage sag
caused by a Line-to-Line fault with a resistance of
0.5 are depicted in Fig. 8. The fault, taking place on
50% of the transmission-line length, starts at 0.08sec
and is cleared at 0.18sec.
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5. P. Harichandana et al Int. Journal of Engineering Research and Application
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Fig.9: (a) Load Voltage. (b) Injected Voltages for the
depressed Phases. (c) DC-Link Voltage.
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Fig.11: For Non-Linear load (a) Supply Voltage. (b)
Estimated RMS supply Voltage of depressed phase.
(c) Injected Voltage magnitudes for the depressed
voltage.
As shown in Fig. 9(a)–(c) depicts the
injected voltages for the depressed phases, the
restored load voltages, and DC-Link voltage.
4.2 Sag Compensation under Non-Linear Loads
4.2.1 Single Line-to-Ground Fault
The performance of the proposed DVR
control scheme during voltage sags caused by single
line-to-ground (SLG) and line-to-line (LL) faults
under non linear load conditions is investigated in
this subsection.
Fig.12: For Non-Linear load (a) Load Voltage. (b)
Injected Voltages for the depressed Phase. (c) DCLink Voltage.
Fig.10: Simulation Model of Sag compensation
during SLG fault under non liner load.
The most common form of static power converters
(nonlinear loads) is the three phase Diode rectifier
type. Modeling circuit and results of simulations for
SLG fault with a fault resistance of 0.5Ω are shown
in Figs. 10 and 11. The short-circuit, taking place on
30% of the length of the parallel transmission line
connected to starts at 0.08sec and is cleared at
0.16sec. Fig. 12(a)–(c) depicts the injected voltages
for the depressed phases, the restored load voltages,
and DC-Link voltage. Control system of this
proposed DVR built in subsystem in SIMULINK
model.
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4.2.2 Sag Compensation During LL Fault under
BLDC motor Drive
BLDC motor drive is widely used in most
common applications now days. For adjustable
speed; a six pulse MOSFET inverter with diode
rectifier used for converting three phase supply to DC
source is used as the non linear load in this
subsection. As shown modeling circuit of BLDC
motor drive in Fig.13, the results of simulations for
BLDC Motor Drive (non-linear load) voltage sag,
caused by an LL fault with a fault resistance of 0.5on 50% of the length of the parallel transmission line,
are shown in Fig. 14. The fault starts at 0.08sec and
clears at 0.18sec.
Fig.13: Simulation Model of Sag Compensation
during LL Fault with BLDC Motor Drive.
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www.ijera.com
and nonlinear load conditions; as well as the
magnitudes of the modulating signals are effectively
limited, under low dc-link voltage conditions. This
enables the DVR in a short time interval (5 ms), with
zero steady-state error.
REFERENCES
[1]
Fig.14: (a) Supply Voltage. (b) Estimated RMS
supply Voltage of depressed phases. (c) Injected
Voltages for the depressed Phases. (d) Restore Load
Voltage.
[2]
[3]
[4]
Fig.15: BLDC Motor (a) Rotor Speed (rpm). (b)
Electromagnetic Torque (
.
[5]
[6]
[7]
Fig.16: BLDC Motor (a) Stator Current
Electromotive Force (EMF).
. (b)
Fig. 14(b) clearly demonstrates that the
estimated supply voltage magnitudes by the LES
filters are not affected considerably by the voltage
harmonics caused by nonlinear loads. Thus, as shown
in Fig. 14(c), the proposed DVR control system is
able to detect and compensate the voltage sags
accurately, under nonlinear load conditions. Fig. 15
and Fig. 14 illustrates that by using the proposed
DVR control strategy, the BLDC motor speed is kept
constant during the simulated voltage sag.
V.
Conclusion
A novel control strategy for independent
control of the injected voltages in each phase of the
DVR. The proposed control strategy effectively
compensates the voltage sags accurately, under linear
www.ijera.com
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Biography
Miss.
P.
Harichandana
obtained his B.Tech in
Electrical and Electronics
Engineering
from
QIS
college of Engineering and
Technology,
Ongole,
Prakasam, Andhra Pradesh.
She is pursuing M.TECH in
Power Electronics and Electrical Drives from
Gudlavalleru Engineering College, Gudlavalleru,
Andhra Pradesh, India. Her areas of interest
include Power Electronics and Electrical
Machines.
Miss. Madhavi sunkara
obtained his B.TECH in
Electrical and Electronics
Engineering
from
Sri
Prakash
College
of
Engineering,
Andhra
Pradesh, India. She received
her M.TECH in Power
Systems from VR Sidhartha Engineerig College,
Andhra Pradesh, India. Her areas of interest
include Power Systems and Power Electronics.
She is currently working as Assistant Professor in
the Electrical and Electronics Engineering
Department in Gudlavalleru Engineering College,
Gudlavalleru, Andhra Pradesh, India.
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