Continuation Power Flow Method based Assessment of Static Voltage Stability c...IJERA Editor
Power system security is recognized as one of the major problems in many power systems throughout the world.
Power system insecurity such as transmission lines being overloaded causes transmission elements cascade
outages, which may lead to complete blackout. In accordance with these reasons, the prediction and recognition
of voltage instability in power system has particular importance and it makes the network security stronger. This
work, by considering the power system contingencies based on the effects of them on Mega Watt Margin
(MWM) and maximum loading point (MLP) is focused to analyse the voltage stability using continuation power
flow method. The study has been carried out on IEEE 30-Bus Test System using MATLAB and PSAT
softwares and results are presented.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
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.
Power Flow Study and Performance of STATCOM and TCSC in Improvement Voltage S...IJAPEJOURNAL
Power systems operation becomes more important as the load demand increases all over the world. This rapid increase in load demand forces power systems to operate near critical limits due to economical and environmental constraints. The objective in power systems operation is to serve energy with acceptable voltage and frequency to consumers at minimum cost. This paper studies the important power system phenomenon and voltage stability by using continuation power flow method and steady-state modeling of Static Synchronous Compensator (STATCOM) and Thyristor Controlled Series Capacitor (TCSC) for continuation power flow studies has been represented and discussed in details.also this paper studies voltage stability by using continuation power flow method and Comparison between performance of TCSC and STATCOM for improve voltage stability has been done. Case studies are carried on 9 bus network. Simulation is done with PSAT in MATLAB. Power Flow and Continuation Power Flow is was implemented using Newton-Raphson method. Simulation results show the proper performance of TCSC and STATCOM to improve voltage control and power flows on the lines and significantly increase the loadability margin of power systems.
Continuation Power Flow Method based Assessment of Static Voltage Stability c...IJERA Editor
Power system security is recognized as one of the major problems in many power systems throughout the world.
Power system insecurity such as transmission lines being overloaded causes transmission elements cascade
outages, which may lead to complete blackout. In accordance with these reasons, the prediction and recognition
of voltage instability in power system has particular importance and it makes the network security stronger. This
work, by considering the power system contingencies based on the effects of them on Mega Watt Margin
(MWM) and maximum loading point (MLP) is focused to analyse the voltage stability using continuation power
flow method. The study has been carried out on IEEE 30-Bus Test System using MATLAB and PSAT
softwares and results are presented.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
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.
Power Flow Study and Performance of STATCOM and TCSC in Improvement Voltage S...IJAPEJOURNAL
Power systems operation becomes more important as the load demand increases all over the world. This rapid increase in load demand forces power systems to operate near critical limits due to economical and environmental constraints. The objective in power systems operation is to serve energy with acceptable voltage and frequency to consumers at minimum cost. This paper studies the important power system phenomenon and voltage stability by using continuation power flow method and steady-state modeling of Static Synchronous Compensator (STATCOM) and Thyristor Controlled Series Capacitor (TCSC) for continuation power flow studies has been represented and discussed in details.also this paper studies voltage stability by using continuation power flow method and Comparison between performance of TCSC and STATCOM for improve voltage stability has been done. Case studies are carried on 9 bus network. Simulation is done with PSAT in MATLAB. Power Flow and Continuation Power Flow is was implemented using Newton-Raphson method. Simulation results show the proper performance of TCSC and STATCOM to improve voltage control and power flows on the lines and significantly increase the loadability margin of power systems.
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.
Effects of the Droop Speed Governor and Automatic Generation Control AGC on G...IJAPEJOURNAL
In power system, as any inequality between production and consumption results in an instantaneous change in frequency from nominal, frequency should be always monitored and controlled. Traditionally, frequency regulation is provided by varying the power output of generators which have restricted ramp rates. The Automatic Generation Control AGC process performs the task of adjusting system generation to meet the load demand and of regulating the large system frequency changes. A result of the mismatches between system load and system generation, system frequency and the desired value of 50 Hz is the accumulation of time error. How equilibrium system frequency is calculated if load parameters are frequency dependent, and how can frequency be controlled. Also, how do parameters of a speed governor affect generated power. The transient processes before system frequency settles down to steady state. Finally, AGC in what way is it different from governor action. This paper presents new approaches for AGC of power system including two areas having one steam turbines and one hydro turbine tied together through power lines.
Transient Stability Assessment and Enhancement in Power SystemIJMER
Power system is subjected to sudden changes in load levels. Stability is an important concept
which determines the stable operation of power system. For the improvement of transient stability the
general methods adopted are fast acting exciters, circuit breakers and reduction in system transfer
reactance. The modern trend is to employ FACTS devices in the existing system for effective utilization
of existing transmission resources. The critical clearing time is a measure to assess transient instability.
Using PSAT, the critical clearing time (CCT) corresponding to various faults are calculated. The most
critical faults were identified using this calculation. The CCT for the critical faults were found to change
with change in operating point. The CCT values are predicted using Artificial Neural Network (ANN) to
study the training effects of ANN. TCSC is selected as the FACTS device for transient stability
enhancement. Particle Swarm Optimization method is used to find the optimal position of TCSC using
the objective function real power loss minimization. The result shows that the technique effectively
increases the transient stability of the system
Series of blackouts encountered in recent years in power system have been occurred because either of voltage or angle instability or both together was not detected within time and progressive voltage or angle instability further degraded the system condition, because of increase in loading. This paper presents the real-time assessment methodology of voltage stability using Phasor Measurement Unit (PMU) with observability of load buses only in power network. PMUs are placed at strategically obtained location such that minimum number of PMU’s can make all load buses observable. Data obtained by PMU’s are used for voltage stability assessment with the help of successive change in the angle of bus voltage with respect to incremental load, which is used as on-line voltage stability predictor (VSP). The real-time voltage phasors obtained by PMU’s are used as real time voltage stability indicator. The case study has been carried out on IEEE-14 bus system and IEEE-30 bus systems to demonstrate the results.
Enhancement of Voltage Stability on IEEE 14 Bus Systems Using Static Var Comp...paperpublications3
Abstract: This paper investigates the effects of Static Var Compensator (SVC) on voltage stability of a power system. One of the major causes of voltage instability is the reactive power limit of the system. Improving the system’s reactive power handling capacity via Flexible AC transmission system (FACTS) devices is a remedy for prevention of voltage instability and hence voltage collapse. The effects of Static Var Compensator (SVC) in static voltage stability margin enhancement will be studies. Prediction of the stability margin or distance to voltage collapse is based on the reactive power load demand. The load is connected to several selected buses. The analysis is performed for IEEE 14 Bus system. Then, the most critical mode is identified for each system. IEEE standard test system has been considered and Load flows were computed by using Newton Raphson method with the help of MATLAB and a weak bus is identified.
A Literature Review on Experimental Study of Power Losses in Transmission Lin...paperpublications3
Abstract: The flexible Ac transmission system (FACTS) controllers can play an important role in the power system security enhancement. However, due to high capital investment, it is necessary to locate these controllers optimally in the power system. FACTS devices can regulate the active and reactive power control as well as adaptive to voltage-magnitude control simultaneously because of their flexibility and fast control characteristics. Placement of these devices in suitable location can lead to control in line flow and maintain bus voltages in desired level and so improve voltage stability margins. In the previous paper three type of FACTS devices used in transmission lines for improvement of voltage profile in the power system. This paper describes the simulation result of flexible Alternative Current Transmission Systems (FACTS) devices used in the disturbed power systems. Out of three types of FACTS device UPFC performances is considered to be best comparatively with respect to each of the three devices.
This paper studies the suitability of a vector based current control which is mostly employed for its faster response in the reactive current applications of static compnesators (STATCOMs). The current control is mostly achieved using proportional-integral (PI) controllers because of the advantage of their good tracking and small variations. However, due to the dependency of PI controllers on the modular multilevel converter (MMC) system dynamics, performance variations arise during steady-state STATCOM non-ideal operations. This paper presents an improved MMC based STATCOM control with a d-q compensation algorithm added to the vector based current control. The algorithm is derived to tackle the effects of the dynamics of the MMC and the STATCOM ideal variations without the use of any additional controller. The control is achieved by providing a power compensation in the d,q-axis which injects currents at the input of the PI controllers in order to improve the steady-state performance of the STATCOM control.
Under voltage load shedding for contingency analysis to optimize power loss ...elelijjournal
Power system contingency is a condition of operation which may be caused due to line outage in a system
and could lead to entire system voltage instability. This may further result in voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction and estimating voltage stability margin
is an important task in power system operation and planning. In this paper Line Stability Index Lij utilizing
the concept of power flow in a single line is adopted to determine the condition of voltage instability. The
purpose of Lij is to determine the point of voltage instability, the weakest bus in the system and the critical
line referred to a bus. Analytical approach based technique for load shedding has been developed as a solution for secured operation of power system under various contingency conditions to optimize the power
flow in order to minimize the system losses within acceptable limit. To validate the effectiveness of the
proposed method simulation has been carried out on IEEE 14 bus system.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
Predicting Post Outage Transmission Line Flows using Linear Distribution FactorsDr. Amarjeet Singh
In order to design and implement preventive
and remedial actions, a continuous performance of fast
security analysis is imperative amid outages of system
components. Following the contingency of a system
component, State estimation and Load flow techniques
are the two popular techniques used to determine
system state variables leading to estimation of flows,
losses and violations in nodal voltages and transmission
line flows. But the dynamic state and complexity of the
system requires faster means of estimations which can
be achieved by linear distribution factors. The use of
Distribution factors in form of Power Transfer
Distribution Factors (PTDF) and Line Outage
Distribution Factors (LODF) which are transmission
line sensitivities with respect to active power exchanges
between buses and transmission line outages offer an
alternative to these two techniques being linear,
quicker, and non-iterative. Following the estimation of
the linear distribution factors from a reference
operating point (base case) and contingency cases
involving line outage, generator output variation and
outage of a Six bus network using Matlab programs,
the results show that by means of Linear Distribution
factors quick estimates of post outage line flows can be
made which match flow results obtained from DC load
flow analysis.
These slides explain about MPPT control and different approaches for wind generation system. Later I will show the comparative results with MATLAB simulation.
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.
Comparison of Shunt Facts Devices for the Improvement of Transient Stability ...IJSRD
This paper presents, the performance of STATCOM placed at midpoint of the two machine power system and compared with the performance of SVC. The comparison of various results found for the different type of faults (single line, double line & three phase fault) occur in long transmission line, and their removal by using shunt FACTS devices is analysed. Computer simulation results under a severe disturbance condition (three phase fault) for different fault clearing times, and different line lengths are analyzed. Both controllers are implemented using MATLAB/SIMULINK. Simulation results shows that the STATCOM with conventional PI controller installed with two machine three bus systems provides better damping oscillation characteristics in rotor angle as compared to two machine power system installed with SVC. The transient stability of two machine system installed with STATCOM has been improved considerably and post settling time of the system after facing disturbance is also improved.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Performance Comparison Between the Original Forms of Biogeography-Based Optim...XperiaZ1
Biogeography-based optimization (BBO) is a new population-based evolutionary algorithm and one of meta-heuristic algorithms. This technique is based on an old mathematical study that explains the geographical distribution of biological organisms. The first original form of BBO was introduced in 2008 and known as a partial migration based BBO. Few months later, BBO was re-introduced again with additional three other forms and known as single, simplified partial, and simplified single migration based BBOs. Then a lot of modifications were employed to enhance the performance of BBO. However, the literature lacks the explanations and the reasons on which the modifications are based on. This paper tries to clarify this issue by making a comparison between the four original BBO algorithms through a variety of benchmark functions with different dimensions and complexities. The results show that both single and simplified single migration based BBOs are faster, but have less performance as compared to the others. The comparison between the partial and the simplified partial migration based BBOs shows that the preference depends on the population size, problem’s complexity and dimensions and the values of the upper and lower side constraints. The partial migration model wins when these factors, except population size, are increased, and vice versa for the simplified partial migration model. The results can be used as a foundation and a first step of modification for enhancing any proposed modification on BBO including the existing modifications that are described in literature.
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.
Effects of the Droop Speed Governor and Automatic Generation Control AGC on G...IJAPEJOURNAL
In power system, as any inequality between production and consumption results in an instantaneous change in frequency from nominal, frequency should be always monitored and controlled. Traditionally, frequency regulation is provided by varying the power output of generators which have restricted ramp rates. The Automatic Generation Control AGC process performs the task of adjusting system generation to meet the load demand and of regulating the large system frequency changes. A result of the mismatches between system load and system generation, system frequency and the desired value of 50 Hz is the accumulation of time error. How equilibrium system frequency is calculated if load parameters are frequency dependent, and how can frequency be controlled. Also, how do parameters of a speed governor affect generated power. The transient processes before system frequency settles down to steady state. Finally, AGC in what way is it different from governor action. This paper presents new approaches for AGC of power system including two areas having one steam turbines and one hydro turbine tied together through power lines.
Transient Stability Assessment and Enhancement in Power SystemIJMER
Power system is subjected to sudden changes in load levels. Stability is an important concept
which determines the stable operation of power system. For the improvement of transient stability the
general methods adopted are fast acting exciters, circuit breakers and reduction in system transfer
reactance. The modern trend is to employ FACTS devices in the existing system for effective utilization
of existing transmission resources. The critical clearing time is a measure to assess transient instability.
Using PSAT, the critical clearing time (CCT) corresponding to various faults are calculated. The most
critical faults were identified using this calculation. The CCT for the critical faults were found to change
with change in operating point. The CCT values are predicted using Artificial Neural Network (ANN) to
study the training effects of ANN. TCSC is selected as the FACTS device for transient stability
enhancement. Particle Swarm Optimization method is used to find the optimal position of TCSC using
the objective function real power loss minimization. The result shows that the technique effectively
increases the transient stability of the system
Series of blackouts encountered in recent years in power system have been occurred because either of voltage or angle instability or both together was not detected within time and progressive voltage or angle instability further degraded the system condition, because of increase in loading. This paper presents the real-time assessment methodology of voltage stability using Phasor Measurement Unit (PMU) with observability of load buses only in power network. PMUs are placed at strategically obtained location such that minimum number of PMU’s can make all load buses observable. Data obtained by PMU’s are used for voltage stability assessment with the help of successive change in the angle of bus voltage with respect to incremental load, which is used as on-line voltage stability predictor (VSP). The real-time voltage phasors obtained by PMU’s are used as real time voltage stability indicator. The case study has been carried out on IEEE-14 bus system and IEEE-30 bus systems to demonstrate the results.
Enhancement of Voltage Stability on IEEE 14 Bus Systems Using Static Var Comp...paperpublications3
Abstract: This paper investigates the effects of Static Var Compensator (SVC) on voltage stability of a power system. One of the major causes of voltage instability is the reactive power limit of the system. Improving the system’s reactive power handling capacity via Flexible AC transmission system (FACTS) devices is a remedy for prevention of voltage instability and hence voltage collapse. The effects of Static Var Compensator (SVC) in static voltage stability margin enhancement will be studies. Prediction of the stability margin or distance to voltage collapse is based on the reactive power load demand. The load is connected to several selected buses. The analysis is performed for IEEE 14 Bus system. Then, the most critical mode is identified for each system. IEEE standard test system has been considered and Load flows were computed by using Newton Raphson method with the help of MATLAB and a weak bus is identified.
A Literature Review on Experimental Study of Power Losses in Transmission Lin...paperpublications3
Abstract: The flexible Ac transmission system (FACTS) controllers can play an important role in the power system security enhancement. However, due to high capital investment, it is necessary to locate these controllers optimally in the power system. FACTS devices can regulate the active and reactive power control as well as adaptive to voltage-magnitude control simultaneously because of their flexibility and fast control characteristics. Placement of these devices in suitable location can lead to control in line flow and maintain bus voltages in desired level and so improve voltage stability margins. In the previous paper three type of FACTS devices used in transmission lines for improvement of voltage profile in the power system. This paper describes the simulation result of flexible Alternative Current Transmission Systems (FACTS) devices used in the disturbed power systems. Out of three types of FACTS device UPFC performances is considered to be best comparatively with respect to each of the three devices.
This paper studies the suitability of a vector based current control which is mostly employed for its faster response in the reactive current applications of static compnesators (STATCOMs). The current control is mostly achieved using proportional-integral (PI) controllers because of the advantage of their good tracking and small variations. However, due to the dependency of PI controllers on the modular multilevel converter (MMC) system dynamics, performance variations arise during steady-state STATCOM non-ideal operations. This paper presents an improved MMC based STATCOM control with a d-q compensation algorithm added to the vector based current control. The algorithm is derived to tackle the effects of the dynamics of the MMC and the STATCOM ideal variations without the use of any additional controller. The control is achieved by providing a power compensation in the d,q-axis which injects currents at the input of the PI controllers in order to improve the steady-state performance of the STATCOM control.
Under voltage load shedding for contingency analysis to optimize power loss ...elelijjournal
Power system contingency is a condition of operation which may be caused due to line outage in a system
and could lead to entire system voltage instability. This may further result in voltage collapse leading to total blackout of the system. Therefore, voltage collapse prediction and estimating voltage stability margin
is an important task in power system operation and planning. In this paper Line Stability Index Lij utilizing
the concept of power flow in a single line is adopted to determine the condition of voltage instability. The
purpose of Lij is to determine the point of voltage instability, the weakest bus in the system and the critical
line referred to a bus. Analytical approach based technique for load shedding has been developed as a solution for secured operation of power system under various contingency conditions to optimize the power
flow in order to minimize the system losses within acceptable limit. To validate the effectiveness of the
proposed method simulation has been carried out on IEEE 14 bus system.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
Predicting Post Outage Transmission Line Flows using Linear Distribution FactorsDr. Amarjeet Singh
In order to design and implement preventive
and remedial actions, a continuous performance of fast
security analysis is imperative amid outages of system
components. Following the contingency of a system
component, State estimation and Load flow techniques
are the two popular techniques used to determine
system state variables leading to estimation of flows,
losses and violations in nodal voltages and transmission
line flows. But the dynamic state and complexity of the
system requires faster means of estimations which can
be achieved by linear distribution factors. The use of
Distribution factors in form of Power Transfer
Distribution Factors (PTDF) and Line Outage
Distribution Factors (LODF) which are transmission
line sensitivities with respect to active power exchanges
between buses and transmission line outages offer an
alternative to these two techniques being linear,
quicker, and non-iterative. Following the estimation of
the linear distribution factors from a reference
operating point (base case) and contingency cases
involving line outage, generator output variation and
outage of a Six bus network using Matlab programs,
the results show that by means of Linear Distribution
factors quick estimates of post outage line flows can be
made which match flow results obtained from DC load
flow analysis.
These slides explain about MPPT control and different approaches for wind generation system. Later I will show the comparative results with MATLAB simulation.
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.
Comparison of Shunt Facts Devices for the Improvement of Transient Stability ...IJSRD
This paper presents, the performance of STATCOM placed at midpoint of the two machine power system and compared with the performance of SVC. The comparison of various results found for the different type of faults (single line, double line & three phase fault) occur in long transmission line, and their removal by using shunt FACTS devices is analysed. Computer simulation results under a severe disturbance condition (three phase fault) for different fault clearing times, and different line lengths are analyzed. Both controllers are implemented using MATLAB/SIMULINK. Simulation results shows that the STATCOM with conventional PI controller installed with two machine three bus systems provides better damping oscillation characteristics in rotor angle as compared to two machine power system installed with SVC. The transient stability of two machine system installed with STATCOM has been improved considerably and post settling time of the system after facing disturbance is also improved.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Performance Comparison Between the Original Forms of Biogeography-Based Optim...XperiaZ1
Biogeography-based optimization (BBO) is a new population-based evolutionary algorithm and one of meta-heuristic algorithms. This technique is based on an old mathematical study that explains the geographical distribution of biological organisms. The first original form of BBO was introduced in 2008 and known as a partial migration based BBO. Few months later, BBO was re-introduced again with additional three other forms and known as single, simplified partial, and simplified single migration based BBOs. Then a lot of modifications were employed to enhance the performance of BBO. However, the literature lacks the explanations and the reasons on which the modifications are based on. This paper tries to clarify this issue by making a comparison between the four original BBO algorithms through a variety of benchmark functions with different dimensions and complexities. The results show that both single and simplified single migration based BBOs are faster, but have less performance as compared to the others. The comparison between the partial and the simplified partial migration based BBOs shows that the preference depends on the population size, problem’s complexity and dimensions and the values of the upper and lower side constraints. The partial migration model wins when these factors, except population size, are increased, and vice versa for the simplified partial migration model. The results can be used as a foundation and a first step of modification for enhancing any proposed modification on BBO including the existing modifications that are described in literature.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Differential Evolution Based Optimization Approach for Power Factor CorrectionIDES Editor
In radial distribution systems, the voltages at buses
reduces when moved away from the substation, also the losses
are high. The reason for decrease in voltage and high losses is
the insufficient amount of reactive power, which can be
provided by the shunt capacitors. For this purpose, in this
paper, two stage methodologies are used. In first stage, the
load flow of pre-compensated distribution system is carried
out using ‘Dimension reducing distribution load flow
algorithm’. In the second stage, Differential Evolution (DE)
technique is used to determine the optimal location and size
of the capacitors. The above method is tested on IEEE 69 bus
system. In this paper a new method is proposed to improve the
power factor of those buses having low power factor (less than
0.8lag) to unity power factor simultaneously by placing the
capacitors.
Determination of the Weakest Branch in a Radial Distribution System using Rea...IDES Editor
This paper presents a unique and novel
method to determine the weakest branch or heavily
loaded branch of a radial distribution system by
considering reactive loading index range. It is shown that
the branch, at which the value of reactive loading index is
minimum, is considered to be the weakest branch or
heavily loaded branch of the system. The effectiveness of
the proposed method has been successfully tested in 12
bus radial distribution system and the results are found to
be in very good agreement.
Optimal Siting And Sizing Of Distributed Generation For Radial Distribution S...inventy
Research Inventy provides an outlet for research findings and reviews in areas of Engineering, Computer Science found to be relevant for national and international development, Research Inventy is an open access, peer reviewed international journal with a primary objective to provide research and applications related to Engineering. In its publications, to stimulate new research ideas and foster practical application from the research findings. The journal publishes original research of such high quality as to attract contributions from the relevant local and international communities.
Calculating Voltage Instability Using Index Analysis in Radial Distribution ...IJMER
This paper presents analysis of voltage stability index by a simple and efficient load flow
method to find out the magnitude of voltage at each node in radial distribution system in that network. It
shows the value of voltage stability index at each node in radial distribution network and predicts which
node is more sensitive to voltage collapse. This paper also presents the effect on voltage stability index
with variation in active power, reactive power, active and reactive power both. The voltage and VSI and
effect of load variation on VSI for 33-node system & 28-node system are calculated in this paper with
results shown
Investigation and Comparison of the Effect of Facts Devices, Capacitors and L...IJAPEJOURNAL
This paper studies the important power system phenomenon and voltage stability by using continuation power flow method. Voltage collapse scenario is presented which can be a serious result of voltage instability and also the parameters that affected by voltage collapse are discussed. In analyzing power system voltage stability, continuation power flow method is utilized which consists of successive load flows. In this paper steady-state modeling of Static VAR Compensator (SVC) and Unified Power Flow Controller (UPFC) and effect of compensator and variation of line reactance on the voltage stability have been studied and Comparison between performance of UPFC and SVC and installation shunt capacitor and variation of line reactance for improve voltage stability has been done.Case studies are carried on 11 bus network in two areas. Simulation is done with PSAT in MATLAB. Continuation Power Flow was implemented using Newton Raphson method. Simulation results show the proper performance of UPFC, SVC, installation shunt capacitor and variation of line reactance to improve voltage control and significantly increase the loadability margin of power systems.
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 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 Review on Power System Voltage Stability and Optimization TechniquesIJERA Editor
Power system voltage stability is a one of the major focused areas in recent days due to mismatch between generation and demand. Maintenance of voltage stability is a challenging issue in planning and security assessment of power systems. Voltage stability is the ability of a power system to maintain steady acceptable voltages at all buses in the power system under normal operating conditions and after being subjected to a disturbance. Long-term voltage instability problems can occur in heavily loaded systems where the electrical distance is large between the generator and the load. Timely application of reactive power compensation or load shedding may prevent this type of voltage instability. System reactive power handling capacity can be improved with Flexible AC Transmission System (FACTS) devices. Identification of critical system locations to undertake appropriate remedial measures in operation is the concern. This paper reviews the performance of various types FACTS controllers in power system voltage stability problem and focuses on different optimization methods implemented for optimal placement and sizing of FACTS devices to minimize power losses.
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.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Swing, voltage stability and power transfer capability in transmission system...eSAT Journals
Abstract In modern era, the increasing size of the power system, to maximize the use of existing systems and to provide adequate voltage support is an emphasis on finding solutions. This flexibility is needed electricity. Better placed than the Flexible AC Transmission Systems (FACTS) to control the flow of electricity, and to provide voltage support can be effective in turn resulting in less damage. The impact of these tools on line flow and bus voltage profile at random algorithm to determine the optimal number of ratings have been studied by keeping them better . The FACTS devices are expensive cause of that FACTS type, number and location of the FACTS devices is very important, for decide the optimal location and parameters of FACTS devices. FACTS are used in the following purposes: Transmission pricing issues by maximizing social welfare with or without consideration of FACTS’ costs; Better utilization of FACT by maximizing FACTS devices total transferred power; Reactive power or voltage control by minimizing transmission losses, or voltage fluctuation. Increase system’s security under emergency by minimizing transmission lines loadability. Power flow control, a current long transmission line, plays an important role within the energy system. The letter swings, long-distance transmission line voltage and power flow control in unified power flow controller (UPFC) based compensation associated series or shunt FACTS devices are employed. Devices such as the proposed transmission line, between the end of the sending and receiving end to the transmission line is used in places as different. Here also deals with determining the optimum placement of Flexible AC Transmission Systems (FACTS) damping out swings, voltage and improves power transfer devices for a long transmission line. Here the concept of compensation mid-point of facts is presented for optimal placement. Keywords: Stability, first swings, rotor angle, power transfer, Flexible AC Transmission Systems (FACTS), Unified Power Flow Controller (UPFC), reactive power
ASSESSMENT OF VOLTAGE FLUCTUATION AND REACTIVE POWER CONTROL WITH SVC USING PSOKashif Mehmood
Smart grid novel growth in the arena of power, this is a new scheme and apparatus for producing and distributing
electricity. Smart grids are very important part of the electrical circuit. Distribution Management System (DMS) used by the utilities for the
state Estimation (SE). Basic application distribution control system, evaluation (SE) and the control reactive power). There SE principally
used to monitor and to control the entire distributed network. In the distribution network has a problem voltage profile. It is controlled by
distributed generators (DG), which are located in diverse positions in the system to maintain the voltage within certain limits. Validation
through the implementation on the IEEE 14-bus radial transmission system indicated that PSO is reasonable to achieve the
task. MATLAB software is used for results simulation
Location of Shunt FACTS Devices for First-Swing Stability Enhancement in Inte...Editor IJMTER
This paper deals with the location of shunt FACTS devices to improve transient stability
in a long transmission line with predefined direction of real power flow. Shunt Flexible AC
Transmission System (FACTS) devices, when placed at the mid-point of a long transmission line,
play an important role in controlling the reactive power flow to the power network and hence both
the system voltage fluctuations and transient stability. The validity of the mid-point location of shunt
FACTS devices was verified using Simulink, with different shunt FACTS devices, namely static var
compensator (SVC) and static synchronous compensator (STATCOM) in a long transmission line
using the actual line model. It has been observed that the FACTS devices, when placed slightly offcentre towards sending-end, give better performance in improving transient stability and the location
depends on the amount of local/through load. The results are experimented and simulated on
MATLAB/Simulink environment.
Voltage collapse mitigation by reactive power compensation at the load sideeSAT Journals
Abstract Power system stability may be defined as the property of a power system that enables it to remain in a state of operating equilibrium under normal operating conditions and to regain an acceptable state of equilibrium after being subjected to a disturbance. A general and formal definition is given below. The IEEE/CIGRE Joint Task Force has proposed the following definition-“Power system stability is the ability of an electric power system, for a given initial operating condition, to regain a state of operating equilibrium after being subjected to a physical disturbance, with most system variables bounded, so that practically the entire system remains intact.” The challenge faced in the modern power system is the collapse of voltages at heavy loads at the load buses of a power system. The voltage collapse will in turn will effect the stability of the power system. In this paper a novel way of mitigating the voltage collapse by supplying the reactive power at load buses is discussed and encouraging simulation results are obtained. The method employed is as fallows. Simulation is done without SVC and STATCOM at load buses. On comparison of the results at the load buses it is seen that with SVC and STATCOM at the load buses voltage collapse is mitigated in spite of heavily loading the system. Keywords: Voltage Collapse, Reactive Power Management, Load Bus, Power System Stability.
Comparison of FACTS Devices for Two Area Power System Stability Enhancement u...IJAPEJOURNAL
Modern Power Transmission networks are becoming increasingly stressed due to growing demand and restrictions on building new lines. Losing stability is one of the major threat of such a stressed system following a disturbance. Flexible ac transmission system (FACTS) devices are found to be very effective in a transmission network for better utilization of its existing facilities without sacrificing the desired stability margin. The static synchronous compensator (STATCOM) and Static Var Compensator (SVC) are the shunt devices of the flexible AC transmission systems (FACTS) family. When system voltage is low, STATCOM generates reactive power and when system voltage is high it absorbs reactive power whereas the Static Var compensator provides the fast acting dynamic compensation in case of severe faults. In this Paper, the performance of SVC is compared with the performance of STATCOM. Proposed controllers are implemented using MATLAB/SIMULINK. Simulation results indicate that the STATCOM controller installed with two machine systems provides better damping characteristics in rotor angle as compared to two machine system installed with SVC. Thus, transient stability enhancement of the two machine system installed with STATCOM is better than that installed with SVC.
Similar to Welcome to International Journal of Engineering Research and Development (IJERD) (20)
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
The paper addresses the importance of welding design to prevent corrosion at steel. Welding is
used to join pipe, profiles at bridges, spindle, and a lot more part of engineering construction. The
problems happened associated with welding are common issues in these fields, especially corrosion.
Corrosion can be reduced with many methods, they are painting, controlling humidity, and also good
welding design. In the research, it can be found that reducing residual stress on the welding can be
solved in corrosion rate reduction problem.
Preheating on 500oC and 600oC give better condition to reduce corosion rate than condition after
preheating 400oC. For all welding groove type, material with 500oC and 600oC preheating after 14 days
corrosion test is 0,5%-0,69% lost. Material with 400oC preheating after 14 days corrosion test is 0,57%-0,76%
lost.
Welding groove also influence corrosion rate. X and V type welding groove give better condition to reduce
corrosion rate than use 1/2V and 1/2 X welding groove. After 14 days corrosion test, the samples with
X welding groove type is 0,5%-0,57% lost. The samples with V welding groove after 14 days corrosion test is
0,51%-0,59% lost. The samples with 1/2V and 1/2X welding groove after 14 days corrosion test is 0,58%-
0,71% lost.
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
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.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
microbes to enhance oil production through in-situ production of bio-products like bio surfactans, biogenic
gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
(Earth -Moon-Earth) technique. Long distance communication (DXing) using Very High Frequency (VHF)
operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
molecular markers due to their abundance and high degree of polymorphism. The nucleotide sequences of
polymorphic forms of the same gene should be 99.9% identical. So, Microsatellites extraction from the Gene is
crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
Microsatellites on „Y‟ Chromosome” can extract both Perfect as well as Imperfect Microsatellites from large
data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
locate Microsatellites and extracts them.
Importance of Measurements in Smart GridIJERD Editor
- The need to get reliable supply, independence from fossil fuels, and capability to provide clean
energy at a fixed and lower cost, the existing power grid structure is transforming into Smart Grid. The
development of a smart energy distribution grid is a current goal of many nations. A Smart Grid should have
new capabilities such as self-healing, high reliability, energy management, and real-time pricing. This new era
of smart future grid will lead to major changes in existing technologies at generation, transmission and
distribution levels. The incorporation of renewable energy resources and distribution generators in the existing
grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
One of the major environmental concerns is the disposal of the waste materials and utilization of
industrial by products. Lime stone quarries will produce millions of tons waste dust powder every year. Having
considerable high degree of fineness in comparision to cement this material may be utilized as a partial
replacement to cement. For this purpose an experiment is conducted to investigate the possibility of using lime
stone powder in the production of SCC with combined use GGBS and how it affects the fresh and mechanical
properties of SCC. First SCC is made by replacing cement with GGBS in percentages like 10, 20, 30, 40, 50 and
by taking the optimum mix with GGBS lime stone powder is blended to mix in percentages like 5, 10, 15, 20 as
a partial replacement to cement. Test results shows that the SCC mix with combination of 30% GGBS and 15%
limestone powder gives maximum compressive strength and fresh properties are also in the limits prescribed by
the EFNARC.
Study of Macro level Properties of SCC using GGBS and Lime stone powder
Welcome to International Journal of Engineering Research and Development (IJERD)
1. International Journal of Engineering Research and Development
e-ISSN: 2278-067X, p-ISSN : 2278-800X, www.ijerd.com
Volume 5, Issue 2 (December 2012), PP. 64-81
Security Assessment of an Interconnected Power System
Considering Voltage Dependent Loads with Dynamic Tap
Changer and Exponential Recovery Loads Using Interline
Power Flow Controller
T.A. Ramesh Kumaar1, Dr.I.A. Chidambaram2
1
Assistant Professor, Department of Electrical Engineering, Annamalai University, Chidambaram- India
2
Professor Department of Electrical Engineering, Annamalai University, Chidambaram- India
Abstract:- Power system architecture today are being made more complex and they require more sophisticated
new technologies or new devices such as Flexible AC Transmission Systems (FACTS). The limiting factor of the
stability and the determination of the transfer limits depend on the load-voltage characteristic since load relief due
to the load-voltage dependency results in larger transfer limits.This paper deals with the overview of a control
strategies for the security assessment of an interconnected power system coordinated with different loads which
can be governed by FACTS especially Interline Power Flow Controller (IPFC) devices when the system is
approaching an extreme emergency state. IPFC is employed to enhance power system stability in addition to their
main function of power flow control. In this method, the island is prevented from the total loss of supply using few
FACTS devices. The optimization process is carried out using bacterial foraging optimization algorithm. The
optimized result exhibits tremendous improvement in the system performance. when the proposed scheme is
adopted in a IEEE 14 bus test system.
Keywords:-Flexible AC Transmission System (FACTS), Interline Power Flow Controller (IPFC),
Voltage Dependent Load (VDL) with Dynamic Tap Changer, Exponential Recovery Loads (ERL), Dynamic
Security Assessment (DSA).
I. INTRODUCTION
Power system dynamic behaviour analysis requires adequate modelling of various utilities with the consideration
of their parameter values that ensure those models with replicate reality. In many cases, the level of approximation is
determined by the nature of the study. Load modelling provides an example. It is common for the aggregate behaviour of
loads to be represented by a Voltage Dependent Loads with Dynamic Tap Changer and Exponential Recovery. The loads
models will be a gross approximation, which provides information about the complex composition of the loads. This
deficiency is particularly evident in distribution systems that supply a significant motor load, as the Voltage Dependent
Loads with Dynamic Tap Changer and the Exponential Recovery Load model cannot capture the delayed voltage recovery.
Design procedure arising from system dynamic behaviour can also be thought of in an optimization framework. However,
any the optimization formulation must capture the processes driving dynamics. This class of problem be optimized
efficiently using advanced computational procedures is referred as optimization algorithm. The classification of models is a
decision that should be made based on the knowledge of the actual system composition and the phenomena that are being
studied.
In a power system network, there are often multiple loads connected to a single bus, normally the power of
individual load is not measured or not available, but the total power transmitted through the bus is measured. In these cases,
the loads can be considered as one composite load, which consists of static loads and dynamic or nonlinear loads. In recent
years, many techniques have been proposed to model such loads . However, most of them are based on an assumed load
equation and the parameters of the equation are estimated through curve fitting. Because of the complexity of modern loads
(for example, power electronics loads), the assumed models may not capture power, frequency and voltage phenomena
simultaneously and accurately. It is necessary to investigate new load modelling techniques to establish accurate load models
for power system stability analysis. When a power system is subjected to large disturbances, such as [1] simultaneous loss of
several generating units or major transmission lines, and the vulnerability analysis indicates that the system is approaching a
catastrophic failure and more efficient and fast control actions need to be taken to limit the extent of the disturbance.
Even with the FACTS controllers like Static Var Compensators, Unified Power Flow Controllers, Interline Power Flow
Controllers trade-offs provides improved damping by optimization or tuning the controller even for small-signal conditions.
As a consequence, the performance during the transient period immediately following a large disturbance may be degraded.
FACTS devices’ output limiters attempt to balance these competing effects. It can be shown that the tuning of these limiter
values can be formulated as a bacterial foraging optimization problem. In contrast to design, analysis of system dynamics is
more aligned with understanding extremes of system behaviour. The method has two stages. The first stage is to choose the
weakest bus. The second stage includes a restoration process. Load restoration depends on the droop characteristic of the
generators and maximum power transfer capability of the utilities.
This paper discusses a vision for the solution for the power quality by improving the power system restoration
through improved monitoring and control. The demand for larger power transfers over longer-distances, insufficient
64
2. Security Assessment of an Interconnected Power System Considering Voltage Controller
investment in the transmission system, exacerbated by continued load growth are the trust areas which require continuous
reforms to ensure a quality power supply to the consumers. The basic restoration assessment for Voltage Dependent Loads
with Dynamic Tap Changer and Exponential Recovery Loads model in the power system network has been carried out and
the various control corrective actions using IPFC is considered for the power system security enhancement study.
II. POWER SYSTEM SECURITY ASSESSMENT
Due to the nature of the disturbance and the set up of the power system network, there are two main elements in
the Power System Security Assessment namely Static Security Assessment and Dynamic Security Assessment. Static
Security Assessment is usually performed prior to dynamic security assessment. If the analysis evaluates only the expected
post disturbance equilibrium condition (steady-state operating point), then this is referred as Static Security Assessment
(SSA). Static security is related to an equilibrium point of the system where voltage and thermal limits are observed. It
neglects the transient behavior and any other time dependent variations caused by changes in load conditions [2]. If the
analysis evaluates the transient performance of the system as it progresses after the disturbance is referred as Dynamic
Security Assessment (DSA). Dynamic Security Assessment is an evaluation of the ability of a power system to withstand a
defined set of contingencies and to survive in the transition to an acceptable steady-state condition. DSA refers to the
analysis required to determine whether the power system can meet the specified reliability and security criteria in both
transient and steady-state time frames for all credible contingencies.
In the operating environment, a secure system is one in which operating criteria are given prior important at pre-
and post contingency conditions. This implies that analyses must be performed to assess all aspects of security, including the
thermal loading of system elements, voltage and frequency variations (both steady state and transient), and all forms of
stability. If the system is secured, these oscillations will decay and has to be damped out eventually. Otherwise, the
oscillation of the frequency and voltage will grow to the extent of even shutting down the generator. If the system
experiences a major disturbance, the oscillation will keep growing to a significant magnitude. The stability is then measured
based on the trajectories of the disturbed systems motion related to the region of attraction of the final equilibrium state. For
such situations, the accurate modeling of nonlinear system and regressive analysis of the nonlinear system [3] are to be
adopted. Due to the tremendous growth in the interconnected Power system network with more complicated load models,
increase the possibility of disturbance occurrences and the propagation of the disturbances. So the concept of the preventive
(normal), emergency, and restorative operating states and their associated controls are to be adopted effectively.
2.1. Off-Line DSA
In the off-line DSA analysis, detailed time-domain stability analysis is performed for all credible contingencies
and a variety of operating conditions. In most cases, this the off-line Dynamic stability analysis is used to determine limits of
power transfers across the important system interfaces. Since the analysis is performed off-line there is no severe restriction
on computation time and therefore detailed analysis can be done for a wide range of conditions and contingencies [4]. These
studies include numerical integration of the models for a certain proposed power transfer condition and for a list of
contingencies typically defined by a faulted location and specified fault-clearing time
The simulation results are analyzed to find if voltage transients are acceptable and to verify whether the transient
stability is maintained during the specified fault-clearing time. If the results for one level of power transfer are acceptable for
all credible contingencies, the level of proposed power transfer is increased and the analysis is repeated. This process
continues until the level of power transfer reaches a point where the system cannot survive for all of the credible
contingencies. The maximum allowable transfer level is then fixed at the last acceptable level, or reduced by some small
amount to provide a margin that would account for changes in conditions when the actual limit is in force [5].
III. MATHEMATICAL MODEL OF A POWER SYSTEM
The dynamic behavior of multi-machine power system is described by the detailed modeling of all the elements of
the power system [5].
d 2 d
M D Pei Pmi
dt 2 dt (1)
d 0
0
dt (2)
The general relation for dynamic behavior of a multi-machine power system used for both dynamic and transient
security assessment be represented as
Nj
Pei Ei E j Gij cos 0 1 Bij sin i j
i1
(3)
Where i = 1,2,…………….. Ng. Mi, Di are the inertia and damping constant of the ith generation; Pmi mechanical
input to the ith generator; Ej is the EMF behind X'di of the ith generator; Gij, Bij are the Conductance and Susceptance of the
admittance matrix of the of the reduced system, X'di is the transient reactance of the ith generator; Ng is the number of
synchronous generator in the system. Modification of equ (3) for dynamic security assessment could result as
Md 2
Pmi Pei Pm Pmax,i
dt 2 (4)
65
3. Security Assessment of an Interconnected Power System Considering Voltage Controller
3. 1. Modelling of Dynamic Loads
A load can be mathematically represented with the relationship between power and voltage where the power is
either active or reactive and the output from the model. The voltage (magnitude and/or frequency) is the input to the model.
The load can be a static or dynamic load or a combination of both. Load models are used for analyzing power system
security problems, such as steady state stability, transient stability, long term stability and voltage control. According to the
power voltage equation, power system loads are divided into constant-impedance, constant power and constant current loads.
A considerable amount of loads in power systems are induction motors and as several induction motors are connected to a
busbar and it may be modelled as a single motor, parameters of which are obtained from the parameters of all motors and is
referred as dynamic load modelling. [6].
The dynamic load model describes the time dependence as well as the voltage dependence of the load. The
characteristic of a bus load depends on the load composition, which means that the aggregated load characteristics for the
bus load must be found. These load parameters can be derived by field measurement based method which is based on direct
measurement at a bus, during system disturbances or planned system disturbances, where voltage, frequency, active power
and reactive power are measured. Then a method, such as the Least Square Method is used to derive parameters to the
aggregated load model.
Field Measurement Based Method is a simple Straightaway approach to derive a model. Unless the load
composition is analysed in detail and unless buses having loads of fairly different compositions are measured there will not
be performance analysis of the system and can even be extrapolated to different conditions. Spontaneous load variations are
included in the load model, especially during long term measurements. Traditionally, lumped feeder loads are represented as
static composite load models on the basis of constant impedance, constant current or constant power contributions. Models
resulted in a classical dynamic model that was however still treated as linear in its voltage and frequency dependence of
active and reactive powers [7]
IV. MATHEMATICAL MODEL OF DYNAMIC LOAD
The General form of Load Modelling equation can be written as, [8]
.
x a ( x, v ) (5)
PH b p ( x, v )
(6)
Q H b p ( x, v )
(7)
PH b p ( x (), v )
(8)
Where bp x(∞) solve x = 0, i.e. a(x, v) = 0 for static load characteristic and,
PH b p ( x(0), v)
(9)
Where PH is a Active power consumption model, x (0) is the value of the state when the initial change occurs.
Dynamic load model with exponential recovery had also been proposed in [8], a differential equation that defines the
behaviour of simple dynamic load model based on the response to a voltage step is given by [9].
.
T p PH PH Ps (V ) k p (V )V
(10)
Where
K p (V ) Tp Pt (v)v
This equation can be written in first-order form as
.
.
Xp
PH Pt (V )
Tp
(11)
.
.
X Ps (V ) PL
p
(12)
Where Tp is a Active load recovery time, Pt(v) is a Transient part of active power consumption, XP is a state
variable, PS (V) is the static load function . Using this form of differential equation, for active as well as reactive powers, the
system voltage can be determined after the disturbance [9].
4.1.1. Voltage Dependent Loads with Dynamic Tap Changer
Voltage Dependent Loads with Dynamic Tap Changer are nonlinear load model which represents the power
relationship to voltage as an exponential equation. The transformer model consists of an ideal circuit with tap ratio n, hence
the voltage on the secondary winding is vs = v/n. The voltage control is obtained by means of a quasi-integral anti-windup
regulator The load powers PH and QH are preceded as negative power as these powers are absorbed from the bus, as follows:
(13)
(14)
66
4. Security Assessment of an Interconnected Power System Considering Voltage Controller
and the differential equation is
(15)
Where Kd is the Anti-windup regulator deviation Ki is the Anti-windup regulator gain. The reference voltage sign
is negative due to the characteristic of the stable equilibrium point. If voltage dependent loads with embedded dynamic tap
changer are initialized after the power flow analysis, the powers p0 and q0 are computed based on the constant PQ load
powers pL0 and qL0 as (17and18) and the state variable n and the voltage reference vref are initialized as follows
(16)
Where v0 is the initial voltage of the load bus The parameters of this model are γp, γq, and the values of the active
and reactive power, Po and Qo, at the initial conditions. Common values for the exponents of the model for different load
components 𝛾p and γq are (0, 1, 2). Equations can be directly included in the formulation of power flow analysis; where the
γp and γq the active and reactive power exponent. The units of P0 and Q0 depend on the status parameter k. If k=1, the Voltage
Dependent Loads with Dynamic Tap Changer is initialized after the power flow analysis, and P 0and Q0 are in percentage of
the PQ load power connected at the Voltage Dependent Loads with Dynamic Tap Changer bus.
(17)
(18)
Where KP and KQ are Active and Reactive power rating of the loads
4.2.1. Exponential recovery load
A nonlinear load model which represents the power relationship to voltage as an exponential equation as
(19)
Where ps and pt are the static and transient real power absorptions, which depends on the load voltage
(20)
where γt is a static active power exponent, γs is a dynamic active power exponent β s is a static reactive power
exponent, βt is a dynamic reactive power exponent, of the load models, V is the actual voltage and V o is the nominal voltage.
Note that constant power, constant current and constant impedance are special cases of the exponential model.
Similar equation holds for the reactive power
(21)
(22)
Where qs is the Static reactive load power as a function of bus voltage magnitude and q s is the Dynamic reactive
load power as a function of bus voltage magnitude. The power flow solution and the PQ load data are used for determining
the value of po, Qo, and Vo. In particular po and Qo are determined as below. A PQ load is required to initialize the
Exponential recovery load bus.
(23)
(24)
The parameters of the load can be defined based on the PQ load powers P L0 and QL0:
g PL 0 I p PL 0 Pm
g 2
, Ip , Pm PL 0
100 v0 , 100 v0 100
b QL 0 I q QL 0 Qm
b 2
, Iq , Qm QL 0
100 v0 , 100 v0 100
in this case initial voltage V0 is also not known, thus the following equation is used.
PH gv2 I p v Pm
(25)
67
5. Security Assessment of an Interconnected Power System Considering Voltage Controller
QH bv2 I q v Qm
(26)
The parameters are constants and indicate the nominal power is divided into constant power, constant current and constant
impedance [10]
4.2. Identification of Model Parameters.
PH 1 K p (V 1) .(1 Pdrop ) Pdyn .(G.V 2 1)
(27)
QH 1 K q (V 1) .(1 Qdrop ) Qdyn .(B..V 1)
2
(28)
Considering the model given by equation (27), the nonlinear relationship between the measured signals, active power P,
voltage V at the load bus, the estimated conductance G, and the parameters KP, Pdrop and Pdyn can be simplified by re-
parameterization, and the model can be written as a linear regression equation
PH x(1) x(2).(V 1) Pdyn.(G..V 2 1)
(29)
Where
x(1) (1 Pdrop )
x(2) x(1).K p
z(t ) T (t ). p
(30)
p ( x(1). x(2). Pdyn )
(31)
The Least Squares method has then been used for the identification [10]. The objective is to obtain the best
estimates for the parameter vector θP, which minimizes the difference between the estimated active power and the simulated
one (as a quadratic criterion). With the given equation (27) the same procedure is applied for the parameter identification for
the reactive load using equation (28). The augmented objective functions to be minimized using a least square criterion
which is given by equation (31). The final parameters are determined directly from the expressions given in (29) and (30)
The least squares method is used to minimize the function (30) and to obtain the best estimates for the parameter vector θp.
2
P t K , p Pmeasured K , p
N
L( p ) simulated t
k 1 (32)
The same procedure is repeated for the reactive powers also. The optimum solution represents the of the global
minimum of the objective function, i.e. the best estimates for the model. However, the nonlinear model parameters can be
estimated accurately by an iterative approach whose algorithm is as follows:
* An initial estimate Xo for the parameters is selected;
* The best fit is then determined by using the initial estimate Xo; the best estimates are compared with the initial estimates,
and it is determined whether the fit improves or not. The direction and magnitude of the adjustment depend on the fitting
algorithm [10].
V. OPERATION AND MATHEMATICAL MODEL OF INTERLINE POWER FLOW
CONTROLLER UNIT
The development of FACTS-devices [11-12] in ensuring high reliability as well as high efficiency with the modern
power electronic components has elaborated the usage in various applications in the power system network. Voltage Source
Converters (VSC) provides a free controllable voltage in magnitude and phase due to pulse width modulation of the IGBTs
or IGCTs. High modulation frequencies allow to get low harmonics in the output signal and even to compensate disturbances
coming from the network. The disadvantage is that with an increasing switching frequency, the losses are increasing as well.
Therefore special designs of the converters are required to compensate this. Among various FACTS devices like SVC, SSSC,
TCPS, UPFC it has been proven that even for multiline control IPFC contributes a lot [13]. So in this case study IPFC has
been considered.
68
6. Security Assessment of an Interconnected Power System Considering Voltage Controller
Fig.1 .Power- injection model of FACTS device for power flow
5.1. Steady state representation and load flow model of Interline Power Flow Controller (IPFC)
When the power flows of two lines to be controlled, an Interline Power Flow Controller (IPFC) which consists of
two series VSCs whose DC capacitors are coupled can be used. This allows active power to circulate between the VSCs.
Fig.2 (a, b) shows the principle configuration of an IPFC. With this configuration two lines can be controlled simultaneously
to optimize the network utilization. In general, due to its complex setup, specific application cases need to be identified
[14-15].
Fig.2. (a) Schematic representation of an IPFC with two voltage source converters (b) Power injection model of IPFC
In this circuit,
the complex Controllable series injected voltage is V sem = Vsem ےθsem
Series transformer impedance Zsem = Rsem + jXsem
the complex bus voltage at buses sm and rm be Vrm = Vsm ےθrm and
Vsm = Vsm ےθsm , Ztm = Rtm + jXtm and Btm represent the line series impedance and line charging susceptance, respectively
[16-17], while m is the line number (m = 1,2….). From Fig (4), for one of the lines, the relations can be derived as follows
Fig.3. Equivalent circuit of IPFC with two voltage source converters
Vsm Vsm I sm Z sem Vtm
(33)
I sm
Vtm Vrm j Btm V
tm
Z tm 2
(34)
Vtm and Ism can be expressed according to Vrm and Irm as
B
Vtm 1 j tm Z tm Vtm I rm Z tm
2
(35)
B 2
B
I sm jBtm j
Z tm Vtm 1 tm Z tm I rm
tm
4 4
(36)
From eqn. (33-36) Ism and Irm can be expressed in terms of Vsm, Vrm, and Vsem Ism and Irm
SE E E
I sm A Vrm Vsm Vsem
L L L (37)
69
7. Security Assessment of an Interconnected Power System Considering Voltage Controller
S 1 1
I rm Vrm Vsm Vsem
L L L (38)
Where
B2 t m Bt
A j Btm Z tm
E 1 jZ tm m
4
4
S Z sem A E ,
L Z sem E Z tm ,
Where Vsm, Ism, Vrm, Irm, and Vtm are the complex bus voltages and currents at the corresponding buses s m and rm
respectively. As IPFC neither absorbs nor injects active power with respect to the AC system [18], the active power
exchange between or among the converters via the dc link is zero, and if the resistances of series transformers are neglected,
the equation can be written as
Pc Pd m 0
m (39)
Where
Pdm = Real ( Vsem Ism).
Pdm is a active power exchange on the DC link, V sem is the series injected voltage and Ism complex bus current at bussm.
Thus, the power balance equations are as follows
Pgm Pinj ,m Pim Ptm 0
(40)
Qgm Qinj ,m Qim Qtm 0
(41)
Where Pgm and Qgm are generations active and reactive powers, P lm and Qlm are load active and reactive powers. P t,m and Qt,m,
are conventional transmitted active and reactive powers at the bus m = “ i” and “ j”.
1. Real power loss
This objective consists to minimise the real power loss P L in the transmission lines that can be expressed as,
(42)
where Ns number of buses; Vk <∝k and Vh < ∝h respectively voltages at bus k and h, Ykh and θkh respectively modulus and
argument of the kh-th element of the nodal admittance matrix Y.
2. Voltage deviation
This objective is to minimize the deviation in voltage magnitude at load buses that can be expressed as,
(43)
where NL number of load buses; ref Vi prespecified reference value of the voltage magnitude at the i-th load bus, ref Vi is
usually set to be 1.0 p.u.
VI. BACTERIAL FORAGING OPTIMIZATION ALGORITHM
For over the last five decades, optimization algorithms like Genetic Algorithms (GAs), Evolutionary Programming
(EP), Evolutionary Strategies (ES) which had drawn their inspiration from evolution and natural genetics have been
dominating the realm of optimization algorithms. Recently natural swarm inspired algorithms like Particle Swarm
Optimization (PSO), Ant Colony Optimization (ACO) have found their way into this domain and proved their effectiveness.
Bacterial Foraging Optimization Algorithm (BFOA) [21] was proposed by Passion is inspired by the social foraging
behavior of Escherichia coli. Application of group foraging strategy of a swarm of E-.coli bacteria in multi-optimal function
optimization is the key idea of the new algorithm [22]. Bacteria search for nutrients in a manner to maximize energy
obtained per unit time. Individual bacterium also communicates with others by sending signals. A bacterium takes foraging
decisions after considering two previous factors.
The process, in which a bacterium moves by taking small steps while searching for nutrients, is called chemo taxis
and key idea of BFOA is mimicking chemotactic movement of virtual bacteria in the problem search space. The control of
these bacteria that dictates how foraging should proceed and can be subdivided into four sections namely Chemotaxis,
Swarming, Reproduction, Elimination and Dispersal. These operations among the bacteria are used for searching the total
solution space.
6.1. Chemotactic Step
This process is achieved through swimming and tumbling via Flagella. Depending upon the rotation of Flagella in
each bacterium, it decides whether it should move in a predefined direction (swimming) or altogether in different directions
(tumbling). In BFO algorithm, one moving unit length with random directions represents “tumbling,” and one moving unit
length with the same direction relative to the final step represents “swimming.” The chemotactic step consists of one
tumbling along with another tumbling, or one tumbling along with one swimming. This movement is can be described as
i
i j 1, k , l i j, l , l C i
T i i
(44)
70
8. Security Assessment of an Interconnected Power System Considering Voltage Controller
Where C (i) denotes step size ; (i) Random vector ; T(i)Transpose of vector (i).
6.2. Swarming Step
A group of E.coli cells arrange themselves in a traveling ring by moving up the nutrient gradient when placed
amidst a semisolid matrix with a single nutrient chemo-effecter. The cells when stimulated by a high level of succinct,
release an attractant aspirate, which helps them to aggregate into groups and thus move as concentric patterns of swarms
with high bacterial density. The mathematical representation for E.coli swarming can be represented by
J cc , P j ,k ,l J cc , j ,k ,l
s
i i
i 1
s
dattract exp( wattract ) m m
s p p
i 2
hrepelent exp( wr epelent )( m m )2
i
i 1 m 1 i1 m1
(45)
Where
JCC - Relative distance of each bacterium from the fittest bacterium
S - Number of bacteria
P - Number of Parameters to be optimized
m - Position of the fittest bacteria
dattract, wattract, hrepelent, are the coefficients representing the swarming behavior of the bacteria.
6.3. Reproduction
The least healthy bacteria eventually die while each of the healthier bacteria asexually split into two bacteria,
which are then placed in the same location. This keeps the swarm size constant. For bacterial, a reproduction step takes place
after all chemotactic steps.
N c 1
J i health J i, j, k , l
j 1
(46)
For keep a constant population size, bacteria with the highest Jhealth values die. The remaining bacteria are allowed
to split into two bacteria in the same place.
6.4. Elimination and Dispersal
In the evolutionary process, elimination and dispersal events can occur such that bacteria in a region are killed or a
group is dispersed into a new part of the environment due to some influence. They have the effect of possibly destroying
chemotactic progress, but they also have the effect of assisting in chemotaxis, since dispersal may place bacteria near good
food sources. In BFOA, bacteria are eliminated with a probability of P ed. In order to keeping the number of bacteria in the
population constant, if a bacterium is eliminated; simply disperse one to a random location on the optimization domain
[23-24].
Problem Formulation
Min J = k2 pi2 + k1 pi + k0 (47)
Subject to:
Pmin ≤ P ≤ Pmax ; Qmin ≤ Q ≤Qmax ; Vmin ≤ V ≤ Vmax
Where k0, k1, k2 are cost coefficients
71
9. Security Assessment of an Interconnected Power System Considering Voltage Controller
START
Initialize variables, Set all loop-counters
and bacterium index i equal to 0
Increase elimination – dispersion loop
counter l = l + 1
No
Stop l = Ned?
Yes Perform
Elimination –
Increase Reproduction loop dispersal
counter k = k + 1 (For i = 1, 2,..
S, with
probability Ped,
eliminates and
No disperse one to a
m < Ns? random location)
Yes
Increase Chemotactic loop counter j = j + 1
X
Perform
Reproduction (by
No
killing the worse j < Nc ?
half of the
population with
higher cumulative
health and splitting Yes
the better half into
two) Y
72
10. Security Assessment of an Interconnected Power System Considering Voltage Controller
Y
Set bacterium index i = i + 1
No
X i < S?
i < S? Yes
Compute J(i,j,k,l), adding the cell to cell
attractant effect to nutrient concentration
and set Jlast = J (i,j-1,k,l)
Tumble (let the i-th bacterium take a step
of height C(i) along tumble vector (i))
Compute J(i,j+1,k,l), with the cell-to-cell
attractant effect
Set swim counter
m=0
k < Ned ? No
Yes
m=m+1
Set No
J(i,j,k,l),,< Jlast?
m = Ns
i,j,k,l),< Jlast?
Yes
Swim (let the i-th bacterium take a step of
height C(i) along the direction of the same
tumble vector (i))
Fig. 4 Flowchart of the Bacterial Foraging Algorithm
73
11. Security Assessment of an Interconnected Power System Considering Voltage Controller
Read the system data
From the bus admittance matrix Ybus
Assume for i =2, 3, 4........,n
And for i = 2, 3.......m for PQ bus
Set iteration count K = 0
B
Find PiK and QiK for i=2, 3, 4....n with
IPFC device
Find ΔPiK for i = 2,3.....n and ΔQiK for i= 2,3,......m
Find ΔPiK , ΔQiK for power flows in IPFC connected
buses
Find maxi ΔPiK maxi ΔQiK and max ΔPijK , ΔQijK
maxi ΔPiK ≤ ε, No
maxi ΔQiK ≤ ε, A
maxi ΔPijK , ΔQijK , ≤ ε
Yes
Find slack bus power and all line powers and line
flows
Print result
No
Stop
Yes
Fig.5. Flowchart for the Proposed Method
74
12. Security Assessment of an Interconnected Power System Considering Voltage Controller
A
Form the conventional Jacobin matrix
Modify Jacobin matrix for
incorporating the IPFC parameter
Solve for ( | V | ) / ( | V | ), δi
Update the bus voltage and the IPFC output voltages
Is the output voltage
magnitude of the B
converter is out of limit
Set voltages at limit value
VII. RESULTS
The performance analysis of a IEEE 14-bus, 5-generator system coordinated with different types of Dynamic load
models without and with IFPC Unit were studied and the optimum utilization requirement with the IPFC device for each
load was determined using BFO technique. In this case of study the buses 5 and 14 are connected with VDL and ERL Loads.
The system under the study is shown in Fig 6 and 7.
Transmission Line #'s
Bus #'s
#
#
Fig.6. IEEE 14-bus test system one line diagram
75
13. Security Assessment of an Interconnected Power System Considering Voltage Controller
Figu.7. IEEE 14-bus test system with IPFC Units
Table.1. Power flow solution for IEEE 14 Bus systems with VDL with Dynamic tap changer Load in bus4, 5 and bus 14.
Bus Voltage Voltage Real Reactive
No. Magnitude Angle Power Power
1 1.0300 0.0000 2.3045 -0.4347
2 1.0000 -5.962 0.1830 0.6624
3 0.9800 -14.773 -0.9420 0.3103
4 0.9602 -11.694 -0.4780 0.0390
5 0.9616 -10.009 -0.0760 -0.0160
6 1.0000 -16.570 -0.1208 0.1122
7 0.9766 -15.192 0.0000 0.0000
8 1.0000 -15.191 0.0000 0.1328
9 0.9607 -17.071 -0.3093 -0.1740
10 0.9595 -17.309 -0.0900 -0.0580
11 0.9757 -17.075 -0.0350 -0.0180
12 0.9822 -17.549 -0.0610 -0.0160
13 0.9753 -17.597 -0.1350 -0.0580
14 0.9474 -18.488 -0.1490 -0.0500
Table. 2. Power flow solution for IEEE 14 Bus systems with Exponential Recovery Load in bus 4, 5 and bus 14.
Voltage Voltage Real Reactive
Bus No.
Magnitude Angle Power Power
1 1.0300 0.0000 2.3502 -0.4376
2 1.0000 -6.071 0.1830 0.6812
3 0.9800 -14.955 -0.9420 0.3166
4 0.9591 -11.915 -0.4780 0.0390
5 0.9606 -10.222 -0.0760 -0.0160
6 1.0000 -17.105 -0.1454 0.1281
7 0.9747 -15.586 0.0100 0.0100
8 1.0000 -15.890 0.0000 0.1435
9 0.9585 -17.493 -0.3150 -0.1860
10 0.9577 -17.750 -0.0900 -0.0580
11 0.9748 -17.562 -0.0350 -0.0180
12 0.9821 -18.079 -0.0610 -0.0160
13 0.9750 -18.166 -0.1350 -0.0580
14 0.9460 -18.956 -0.1490 0.0500
76
14. Security Assessment of an Interconnected Power System Considering Voltage Controller
Table.3. Power flow solution for IEEE 14 Bus systems with Exponential Recovery Loads in Bus4, 5 and Bus 14 with IPFC
Unit
IPFC IPFC IPFC
Bus Power at the Power at the Power at the
No. V Angle Bus V Angle Bus V Angle Bus
p.u p.u p.u
MW MVAR MW MVAR MW MVAR
1 1.0300 0.00 2.3287 -0.1365 1.0300 - 0.00 2.2847 -0.1361 1.0300 0.00 2.3336 -0.1467
2 1.0000 -5.52 0.2475 -0.2012 1.0000 -5.44 0.2473 -0.2391 1.0000 -5.55 0.2476 -0.2364
- - - - - -
3 1.0000 0.2950 1.0000 0.2955 1.0000 0.2953
14.38 0.9420 14.12 0.9420 14.29 0.9420
- - - - - -
4 1.0000 0.0446 1.0000 0.0442 1.0000 0.0443
11.88 0.4780 11.47 0.4780 11.68 0.4780
- - - - -
5 0.9905 0.0236 0.9919 -9.76 0.0238 0.9924 0.0237
10.06 0.0586 0.0588 10.02 0.0586
- - - - - -
6 1.0200 -0.0303 1.0300 0.0193 1.0400 0.0291
16.51 0.1454 16.05 0.1208 16.82 0.1454
- - - - -
7 1.0007 -0.0100 1.0026 0.0000 0.0000 1.0020 -0.0100
15.35 0.0100 14.66 14.89 0.0100
- - -
8 1.0000 0.0000 -0.0042 1.0000 0.0000 -0.0146 1.0000 0.0000 -0.0114
15.34 14.65 16.57
- - - - - -
9 0.9923 -0.1861 1.9950 -0.1740 0.9949 -0.1860
17.15 0.3150 16.38 0.3093 16.91 0.3150
- - - - -
10 0.9893 -0.0581 0.9933 0.0900 -0.0580 0.9951 -0.0580
17.35 0.0900 16.63 16.98 0.0900
- - - - - -
11 1.0008 -0.0180 1.0078 -0.0180 1.0137 -0.0180
17.07 0.0350 16.47 0.0350 16.52 0.0350
- - - - - -
12 1.0064 -0.0160 1.0163 -0.0i60 1.0291 -0.0160
17.50 0.0610 17.08 0.0610 17.96 0.0611
- - - - -
13 1.0030 0.1350 0.0580 1.0121 -0.0580 1.0267 -0.0580
17.68 17.32 0.1350 18.39 0.1351
- - - - - -
14 1.0000 -0.0498 1.0000 -0.0499 1.0000 -0.0495
19.08 0.0499 17.84 0.1499 17.58 0.1490
Table.4. Power flow solution for IEEE 14 Bus systems with VDL with Dynamic Tap Changer Loads in Bus 4, 5 and Bus 14
with IPFC Unit
IPFC IPFC IPFC
Bus Power at the Power at the Power at the
No V Angle Bus V Angle Bus V Angle Bus
p.u p.u p.u
MW MVAR MW MVAR MW MVAR
1 1.0300 0.00 2.2837 -0.1303 1.0300 - 0.00 2.2847 -0.1361 1.0300 0.00 2.2885 -0.1404
2 1.0000 -5.41 0.2472 -0.2102 1.0000 -5.44 0.2473 -0.2391 1.0000 -5.44 0.2473 -0.2441
- - - - - -
3 1.0000 0.2951 1.0000 0.2955 1.0000 0.2955
14.21 0.9420 14.12 0.9420 14.12 0.9420
- - - - - -
4 1.0000 0.0444 1.0000 0.0442 1.0000 0.0442
11.65 0.4780 11.47 0.4780 11.45 0.4780
77
15. Security Assessment of an Interconnected Power System Considering Voltage Controller
- - -
5 1.0220 -9.84 0.0237 0.9919 -9.76 0.0238 0.9928 -9.81 0.0238
0.0588 0.0588 0.0588
- - - - - -
6 1.0200 -0.0382 1.0300 0.0193 1.0400 0.0200
16.01 0.1208 16.05 0.1208 16.32 0.1208
- - -
7 1.0019 0.0000 0.0000 1.0026 0.0000 0.0000 1.0032 0.0000 0.0000
14.96 14.65 14.52
- - -
8 1.0000 0.0000 -0.0109 1.0000 0.0000 -0.0146 1.0000 0.0000 -0.0181
14.95 14.65 14.51
- - - - -
9 0.9937 -0.1740 0.9950 -0.1740 0.9962 0.3093 -0.1740
16.73 0.3093 16.38 0.3093 16.16
- - - - - -
10 0.9904 -0.0580 0.9933 -0.0580 0.9966 -0.0580
16.92 0.0900 16.63 0.0900 16.49 0.0900
- - - - - -
11 1.0013 -0.0180 1.0078 -0.0180 1.0142 -0.0180
16.60 0.0350 16.47 0.0350 16.52 0.0350
- - - - - -
12 1.0064 -0.0160 1.0163 -0.0i60 1.0292 -0.0160
17.00 0.0610 17.08 0.0610 17.47 0.0610
- - - - - -
13 1.0030 -0.0580 1.0121 -0.0580 1.0268 -0.0580
17.18 0.1350 17.32 0.1350 17.90 0.1350
- - - - - -
14 1.0000 -0.0487 1.0000 -0.0490 1.0000 -0.0495
18.61 0.0490 17.84 0.1495 17.11 0.1490
VIII. CONCLUSION
This paper presents the coordinated emergency control with the usage of FACTS device especially IPFC. It has
been found that with the IPFC controller, the risk of load shedding is considerably reduced and can easily be adopted for
emergency control. Moreover the result indicate that this comparison method successfully prevent the system from blackout
and restore the system faster.
APPENDIX
TABLE. 5 .GENERATOR DATA [25]
Generator
1 2 3 4 5
Bus No.
MVA 615 60 60 25 25
xl (p.u.) 0.2396 0.00 0.00 0.134 0.134
ra (p.u.) 0.00 0.0031 0.0031 0.0014 0.0041
xd (p.u.) 0.8979 1.05 1.05 1.25 1.25
x'd (p.u.) 0.2995 0.1850 0.1850 0.232 0.232
x"d (p.u.) 0.23 0.13 0.13 0.12 0.12
T'do 7.4 6.1 6.1 4.75 4.75
T"do 0.03 0.04 0.04 0.06 0.06
xq (p.u.) 0.646 0.98 0.98 1.22 1.22
x'q (p.u.) 0.646 0.36 0.36 0.715 0.715
X"q (p.u.) 0.4 0.13 0.13 0.12 0.12
T'qo 0.00 0.3 0.3 1.5 1.5
T"qo 0.033 0.099 0.099 0.21 0.21
H 5.148 6.54 6.54 5.06 5.06
D 2 2 2 2 2
TABLE.6. BUS DATA [25]
P Q P Q Q Q
Gene Load Load Genera
Bu
Gene rated (p.u.) (p.u.) Bu Generat ted
s
rated (p.u.) s ed min.(p.
No
Ty max. u.)
.
(p.u.) pe (p.u.)
*
1. 2.32 - 0.00 0.00 2 10.0 -10.0
0.169
2. 0.4 0.424 0.217 0.127 1 0.5 -0.4
0 0
3. 0.00 0.234 0.942 0.190 2 0.4 0.00
0 0
4. 0.00 0.00 0.478 0.039 3 0.00 0.00
78
16. Security Assessment of an Interconnected Power System Considering Voltage Controller
0 0
5. 0.00 0.122
0.076 0.016 3 0.00 0.00
0 0
6. 0.00 0.00 0.112 0.075 2 0.24 -0.06
0 0
7. 0.00 0.174 0.00 0.00 3 0.00 0.00
8. 0.00 0.00 0.00 0.00 2 0.24 -0.06
9. 0.00 0.00 0.295 0.166 3 0.00 0.00
0 0
10. 0.00 0.00 0.090 0.058 3 0.00 0.00
0 0
11. 0.00 0.00 0.035 0.018 3 0.00 0.00
0 0
12. 0.00 0.00 0.061 0.016 3 0.00 0.00
0 0
13. 0.00 0.00 0.135 0.058 3 0.00 0.00
0 0
14. 0.00 0.00 0.149 0.050 3 0.00 0.00
0 0
* Bus Type: 1) Swing bus, 2) Generator bus (PV bus) and 3) Load bus (PQ bus)
TABLE.7. LINE DATA [25]
Fro Line
To Resistanc Reactan Tap
m charging
Bus e p.u.) ce (p.u.) ratio
Bus (p.u.)
1 2 0.01938 0.05917 0.0528 1
1 5 0.5403 0.22304 0.0492 1
2 3 0.04699 0.19797 0.0438 1
2 4 0.05811 0.17632 0.0374 1
2 5 0.5695 0.17388 0.034 1
3 4 0.6701 0.17103 0.0346 1
4 5 0.01335 0.4211 0.0128 1
4 7 0.00 0.20912 0.00 0.978
4 9 0.00 0.55618 0.00 0.969
5 6 0.00 0.25202 0.00 0.932
6 11 0.099498 0.1989 0.00 1
6 12 0.12291 0.25581 0.00 1
6 13 0.06615 0.13027 0.00 1
7 8 0.00 0.17615 0.00 1
7 9 0.00 0.11001 0.00 1
9 10 0.3181 0.08450 0.00 1
9 14 0.12711 0.27038 0.00 1
10 11 0.08205 0.19207 0.00 1
12 13 0.22092 0.19988 0.00 1
13 14 0.17093 0.34802 0.00 1
Table.8. Control Parameters of the Bacterial Foraging Algorithm
S.No. Parameters Values
1 Number of bacteria ,S 45
2 Swimming Length, Ns 4
3 Number of chemotactic steps, Nc 95
4 Number of reproduction steps, Nre 4
5 Number of elimination-disperse events, Ned 2
6 Elimination and dispersal Probability, Ped 0.25
7 wattract 0.05
8 wrepelent 12
9 hrepelent 0.02
10 dattract 0.02
11 The run-length unit (i.e., the size of the step taken in 0.1
each run or tumble), C(i)
79
17. Security Assessment of an Interconnected Power System Considering Voltage Controller
Table.9. IPFC Data [15]
Parameters Values (p.u./deg)
Complex control series injected voltage 0.015
Vse1
Complex control series injected voltage 0.0216
Vse2
Phase angle δse1 349.662
Phase angle δse2 185.240
DC link capacitance voltage(Vdc) 2
Qinj (rad) 1.0878
ACKNOWLEDGEMENT
The authors wish to thank the authorities of Annamalai University, Annamalainagar, Tamilnadu, India for the
facilities provided to prepare this paper.
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Authors Profile
I.A.Chidambaram (1966) received Bachelor of Engineering in Electrical and Electronics Engineering
(1987), Master of Engineering in Power System Engineering (1992) and Ph.D in Electrical Engineering
(2007) from Annamalai University, Annamalainagar. During 1988 - 1993 he was working as Lecturer in the
Department of Electrical Engineering, Annamalai University and from 2007 he is working as Professor in the
Department of Electrical Engineering, Annamalai University, Annamalainagar. He is a member of ISTE and
ISCA. His research interests are in Power Systems, Electrical Measurements and Control Systems. (Electrical Measurements
Laboratory, Department of Electrical Engineering, Annamalai University, Annamalainagar–608002, Tamilnadu, India, Tel:-
91-09842338501, Fax: -91-04144-238275).
T.A. Rameshkumaar (1973) received Bachelor of Engineering in Electrical and Electronics Engineering
(2002), Master of Engineering in Power System Engineering (2008) and he is working as Assistant Professor
in the Department of Electrical Engineering, Annamalai University, Annamalainagar. He is currently pursuing Ph.D degree in
Electrical Engineering from Annamalai University. His research interests are in Power Systems, Control Systems, and
Electrical Measurements. (Electrical Measurements Laboratory, Department of Electrical Engineering, Annamalai University,
Annamalainagar - 608 002, Tamilnadu, India,
81