This document discusses using Static Var Compensation (SVC) devices to reduce unbalancing and energy losses in distribution networks. It proposes using intelligent optimization algorithms like Particle Swarm Optimization (PSO), Cuckoo Search Algorithm (CSA), and Firefly Algorithm (FA) to determine the optimal sitting and sizing of SVC devices. The objective function considers losses, neutral line current, and SVC installation costs. Simulations on the IEEE 123 node test system show the proposed method significantly improves the performance of unbalanced distribution networks.
The high penetration of power electronic based distributed energy resources (DERs) has increased the importance and attention given to voltage security of distribution systems. Voltage control in the electrical power system is critical for a proper operating condition. Therefore, distribution systems must have the ability to maintain a secure voltage profile. Using inverters for Volt/VAR control (VVC) can provide a faster response for voltage regulation than traditional voltage regulation devices, such as transformer load tap changers and voltage regulators. The primary objective of this paper is to demonstrate how smart inverters can be used to eliminate the voltage deviation by solving a mixed-integer quadratic program to determine the amount of reactive power that should be injected or absorbed at the appropriate nodes. The proposed method incorporates capacitor banks connected to the network and determines whether to turn on or off the capacitor bank for voltage regulation. These processes will be demonstrated in several cases that are focused on mitigating voltage-dips and swells.
Small Signal Modelling of a Buck Converter using State Space Averaging for Ma...paperpublications3
Abstract: Nowadays, step-down power converters such as buck scheme are widely employed in a variety of applications such as power supplies, spacecraft power systems, hybrid vehicles and power supplies in particle accelerators. This paper presents a comprehensive small-signal model for the DC-DC buck converter operated under Continuous Conduction Mode (CCM) for a magnetic load. Initially, the buck converter is modeled using state-space average model and dynamic equations, depicting the converter, are derived. The proposed model can be used to design powerful, precise and robust closed loop controller that can satisfy stability and performance conditions of the DC-DC buck regulator. This model can be used in any DC-DC converter (Buck, Boost, and Buck-Boost) by modifying the converter mathematical equations.
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 Novel Hybrid Dstatcom Topology for Load Compensation with Non-Stiff SourceIJERA Editor
The distribution static compensator (DSTATCOM) is a shunt active filter, which injects currents into the point
of common coupling (PCC) (the common point where load, source, and DSTATCOM are connected) such that
the harmonic filtering, power factor correction, and load balancing can be achieved. The distribution static
compensator (DSTATCOM) is used for load compensation in power distribution network. A new topology for
DSTATCOM applications with non-stiff source is proposed. The proposed topology enables DSTATCOM to
have a reduced dc-link voltage without compromising the compensation capability. It uses a series capacitor
along with the interfacing inductor and a shunt filter capacitor. With the reduction in dc-link voltage, the
average switching frequency of the insulated gate bipolar transistor switches of the D-STATCOM is also
reduced. Consequently, the switching losses in the inverter are reduced. Detailed design aspects of the series and
shunt capacitors are discussed in this paper. A simulation study of the proposed topology has been carried out
using MATLAB environment and the results analyzed.
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.
Comparative power flow analysis of 28 and 52 buses for 330 kv power grid netw...Onyebuchi nosiri
Newton-Raphson technique was formulated and used to evaluate the electrical performances of the existing 28-bus and improved 52-bus Nigerian 330kV power networks. The Jacobian matrix for both the existing 28-bus and the improved 52-bus Nigerian power system was derived using Newton-Raphson power flow solution method. The steady-state critical bus voltages, voltage and angle profiles at each bus, active and reactive power flows, transformer tap settings, component or circuit loading, generator exciter regulator voltage set points and system losses of these networks were determined to ascertain their effectiveness and proper network reconfiguration. The results obtained showed a better performance of the 52-Bus system in power quality, voltage and angle profiles over the conventional 28-bus system
The high penetration of power electronic based distributed energy resources (DERs) has increased the importance and attention given to voltage security of distribution systems. Voltage control in the electrical power system is critical for a proper operating condition. Therefore, distribution systems must have the ability to maintain a secure voltage profile. Using inverters for Volt/VAR control (VVC) can provide a faster response for voltage regulation than traditional voltage regulation devices, such as transformer load tap changers and voltage regulators. The primary objective of this paper is to demonstrate how smart inverters can be used to eliminate the voltage deviation by solving a mixed-integer quadratic program to determine the amount of reactive power that should be injected or absorbed at the appropriate nodes. The proposed method incorporates capacitor banks connected to the network and determines whether to turn on or off the capacitor bank for voltage regulation. These processes will be demonstrated in several cases that are focused on mitigating voltage-dips and swells.
Small Signal Modelling of a Buck Converter using State Space Averaging for Ma...paperpublications3
Abstract: Nowadays, step-down power converters such as buck scheme are widely employed in a variety of applications such as power supplies, spacecraft power systems, hybrid vehicles and power supplies in particle accelerators. This paper presents a comprehensive small-signal model for the DC-DC buck converter operated under Continuous Conduction Mode (CCM) for a magnetic load. Initially, the buck converter is modeled using state-space average model and dynamic equations, depicting the converter, are derived. The proposed model can be used to design powerful, precise and robust closed loop controller that can satisfy stability and performance conditions of the DC-DC buck regulator. This model can be used in any DC-DC converter (Buck, Boost, and Buck-Boost) by modifying the converter mathematical equations.
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 Novel Hybrid Dstatcom Topology for Load Compensation with Non-Stiff SourceIJERA Editor
The distribution static compensator (DSTATCOM) is a shunt active filter, which injects currents into the point
of common coupling (PCC) (the common point where load, source, and DSTATCOM are connected) such that
the harmonic filtering, power factor correction, and load balancing can be achieved. The distribution static
compensator (DSTATCOM) is used for load compensation in power distribution network. A new topology for
DSTATCOM applications with non-stiff source is proposed. The proposed topology enables DSTATCOM to
have a reduced dc-link voltage without compromising the compensation capability. It uses a series capacitor
along with the interfacing inductor and a shunt filter capacitor. With the reduction in dc-link voltage, the
average switching frequency of the insulated gate bipolar transistor switches of the D-STATCOM is also
reduced. Consequently, the switching losses in the inverter are reduced. Detailed design aspects of the series and
shunt capacitors are discussed in this paper. A simulation study of the proposed topology has been carried out
using MATLAB environment and the results analyzed.
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.
Comparative power flow analysis of 28 and 52 buses for 330 kv power grid netw...Onyebuchi nosiri
Newton-Raphson technique was formulated and used to evaluate the electrical performances of the existing 28-bus and improved 52-bus Nigerian 330kV power networks. The Jacobian matrix for both the existing 28-bus and the improved 52-bus Nigerian power system was derived using Newton-Raphson power flow solution method. The steady-state critical bus voltages, voltage and angle profiles at each bus, active and reactive power flows, transformer tap settings, component or circuit loading, generator exciter regulator voltage set points and system losses of these networks were determined to ascertain their effectiveness and proper network reconfiguration. The results obtained showed a better performance of the 52-Bus system in power quality, voltage and angle profiles over the conventional 28-bus system
Performance Improvement of the Radial Distribution System by using Switched C...idescitation
Distribution system is the major link which provides supply to the consumers
from the high voltage transmission system. The load on the distribution system is not
constant and it changes with respect to time throughout the working period. The voltage
drop and power losses occur in the distribution system mainly depends on the nature of the
load which is applied on the system. The voltage drop and power losses frequently occurs
mainly on those systems which are supplying load to the industrial areas, this is mainly
because of the existence of more reactive power. To overcome these problems shunt
compensation is employed to reduce or suppress those effects to an extent. The main aim of
this paper is to determine the specific value of the shunt capacitance required to achieve the
permissible voltage tolerance limits and maximum percentage of power loss reduction in a
sample two feeder radial distribution system.
In power engineering the power flow analysis (also known as load flow study) is an important tool involving numerical analysis applied to a powe r system. This project deals with a model of existing power system using the actual data taking care of all parameters required for the simulation and analysis. With the help of Maharasht ra State Electricity Transmission co. Ltd.,a model of 220KV lines,of Solapur District grid usin g MATLAB software will be modeled. In this project,an algorithm will be used for power f low study and data collection and coding required for modeling. Load flow studies will be ca rried out using Newton Raphson method and voltage profile of buses will be analyzed. New meth od for the improvement of voltage profile will be suggested and analyze using the developed m odel. The optimization techniques include power factor compensation,tap changing,up gradati on of substation,up gradation of line and load shifting will be analyzed. Importance of power flow or Load flow studies is in planning future expansion of power system as well as determi ning the best operation of existing systems. From results of simulation buses with low voltage p rofile will be identified and possible solutions can be suggested.
DISTRIBUTION LOAD FLOW ANALYSIS FOR RDIAL & MESH DISTRIBUTION SYSTEMIAEME Publication
Power flow analysis is the backbone of power system analysis and design. They are necessary for planning, operation, economic scheduling and exchange of power between utilities. Power flow analysis is required for many other analyses such as transient stability, optimal power flow and contingency studies. The principal information of power flow analysis is to find the magnitude and phase angle of voltage at each bus and the real and reactive power flowing in each transmission lines. Power flow analysis is an importance tool involving numerical analysis applied to a power system. In this analysis, iterative techniques are used due to there no known analytical method to solve the problem. This resulted nonlinear set of equations or called power flow equations are generated.
Using the examples of wave and vector diagrams, we study the conditions for the appearance of components of inactive power in an AC network, which are known as reactive power and distortion power. It is shown that the components of the active, reactive power and distortion power are mutually orthogonal and form a power balance, which can be violated mainly due to methodological errors in calculating these components under conditions of non-stationary mode parameters. It is established that the interaction of reactive power and distortion power occurs at the instantaneous power level, and changing their phase shifts allows you to adjust the shape of the resulting power without involving additional active power in the AC network. The results obtained will allow not only to correctly determine the proportion and nature of the components of inactive capacities, which is valuable for solving the problems of optimizing modes in AC networks, but also to create effective technical means of compensating for the identified inactive capacities in the future.
Performance Analysis and Comparison of Transmission Line Varying the Capacito...ijtsrd
In this paper, performance analysis of transmission line 11 KV with thyristor controlled series capacitor providing stability and power enhancement under the application of PI and PID controllers is compared after varying the capacitance of transmission line capacitor. Simulation results of uncompensated and also for compensated transmission line of 11 KV are compared with PI and PID controllers working with the transmission line system for improving the real power as well as reactive power in the supportive MATLAB environment self tuning is applied through MATLAB PID TUNER for both PID and PI controllers. Sameer Khan | Dr. Aziz Ahmad "Performance Analysis and Comparison of Transmission Line (Varying the Capacitor Value) with (PI and PID) Controllers using TCSC" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-2 , February 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38401.pdf Paper Url: https://www.ijtsrd.com/engineering/electrical-engineering/38401/performance-analysis-and-comparison-of-transmission-line-varying-the-capacitor-value-with-pi-and-pid-controllers-using-tcsc/sameer-khan
Basics of Power systems
Network topology
Transmission and Distribution
Load and Resource Balance
Economic Dispatch
Steady State System Analysis
Power flow analysis
Dynamic System Analysis
Transient stability
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
Renewable energy sources are increasingly being used today and solar energy is the most readily and abundantly available energy source. Boost converters are an integral part of any solar energy system. In order to obtain maximum possible energy from the solar system multi-phase interleaved boost converters are used. This paper presents the small-signal ac modelling and closed loop control of three-phase interleaved boost converter. State–space modelling methodology has been adopted to have linearized equivalent model of the boost converter. The interleaved three-phase boost converter is averaged over its one switching period and perturbed with small ac variations and finally linearized around its quiescent point to have a small signal ac model. Type III compensator is employed to improve the frequency response and closed loop control of three-phase boost converter. The controller design procedure is discussed in detail. The effect of right-half plane zero in non-minimum phase system and the appropriate pole-zero placements to overcome the maximum phase lag in such system is discussed. The compensated closed loop system is tested for load variations to observe the transient response.
Performance Improvement of the Radial Distribution System by using Switched C...idescitation
Distribution system is the major link which provides supply to the consumers
from the high voltage transmission system. The load on the distribution system is not
constant and it changes with respect to time throughout the working period. The voltage
drop and power losses occur in the distribution system mainly depends on the nature of the
load which is applied on the system. The voltage drop and power losses frequently occurs
mainly on those systems which are supplying load to the industrial areas, this is mainly
because of the existence of more reactive power. To overcome these problems shunt
compensation is employed to reduce or suppress those effects to an extent. The main aim of
this paper is to determine the specific value of the shunt capacitance required to achieve the
permissible voltage tolerance limits and maximum percentage of power loss reduction in a
sample two feeder radial distribution system.
In power engineering the power flow analysis (also known as load flow study) is an important tool involving numerical analysis applied to a powe r system. This project deals with a model of existing power system using the actual data taking care of all parameters required for the simulation and analysis. With the help of Maharasht ra State Electricity Transmission co. Ltd.,a model of 220KV lines,of Solapur District grid usin g MATLAB software will be modeled. In this project,an algorithm will be used for power f low study and data collection and coding required for modeling. Load flow studies will be ca rried out using Newton Raphson method and voltage profile of buses will be analyzed. New meth od for the improvement of voltage profile will be suggested and analyze using the developed m odel. The optimization techniques include power factor compensation,tap changing,up gradati on of substation,up gradation of line and load shifting will be analyzed. Importance of power flow or Load flow studies is in planning future expansion of power system as well as determi ning the best operation of existing systems. From results of simulation buses with low voltage p rofile will be identified and possible solutions can be suggested.
DISTRIBUTION LOAD FLOW ANALYSIS FOR RDIAL & MESH DISTRIBUTION SYSTEMIAEME Publication
Power flow analysis is the backbone of power system analysis and design. They are necessary for planning, operation, economic scheduling and exchange of power between utilities. Power flow analysis is required for many other analyses such as transient stability, optimal power flow and contingency studies. The principal information of power flow analysis is to find the magnitude and phase angle of voltage at each bus and the real and reactive power flowing in each transmission lines. Power flow analysis is an importance tool involving numerical analysis applied to a power system. In this analysis, iterative techniques are used due to there no known analytical method to solve the problem. This resulted nonlinear set of equations or called power flow equations are generated.
Using the examples of wave and vector diagrams, we study the conditions for the appearance of components of inactive power in an AC network, which are known as reactive power and distortion power. It is shown that the components of the active, reactive power and distortion power are mutually orthogonal and form a power balance, which can be violated mainly due to methodological errors in calculating these components under conditions of non-stationary mode parameters. It is established that the interaction of reactive power and distortion power occurs at the instantaneous power level, and changing their phase shifts allows you to adjust the shape of the resulting power without involving additional active power in the AC network. The results obtained will allow not only to correctly determine the proportion and nature of the components of inactive capacities, which is valuable for solving the problems of optimizing modes in AC networks, but also to create effective technical means of compensating for the identified inactive capacities in the future.
Performance Analysis and Comparison of Transmission Line Varying the Capacito...ijtsrd
In this paper, performance analysis of transmission line 11 KV with thyristor controlled series capacitor providing stability and power enhancement under the application of PI and PID controllers is compared after varying the capacitance of transmission line capacitor. Simulation results of uncompensated and also for compensated transmission line of 11 KV are compared with PI and PID controllers working with the transmission line system for improving the real power as well as reactive power in the supportive MATLAB environment self tuning is applied through MATLAB PID TUNER for both PID and PI controllers. Sameer Khan | Dr. Aziz Ahmad "Performance Analysis and Comparison of Transmission Line (Varying the Capacitor Value) with (PI and PID) Controllers using TCSC" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-2 , February 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38401.pdf Paper Url: https://www.ijtsrd.com/engineering/electrical-engineering/38401/performance-analysis-and-comparison-of-transmission-line-varying-the-capacitor-value-with-pi-and-pid-controllers-using-tcsc/sameer-khan
Basics of Power systems
Network topology
Transmission and Distribution
Load and Resource Balance
Economic Dispatch
Steady State System Analysis
Power flow analysis
Dynamic System Analysis
Transient stability
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
Renewable energy sources are increasingly being used today and solar energy is the most readily and abundantly available energy source. Boost converters are an integral part of any solar energy system. In order to obtain maximum possible energy from the solar system multi-phase interleaved boost converters are used. This paper presents the small-signal ac modelling and closed loop control of three-phase interleaved boost converter. State–space modelling methodology has been adopted to have linearized equivalent model of the boost converter. The interleaved three-phase boost converter is averaged over its one switching period and perturbed with small ac variations and finally linearized around its quiescent point to have a small signal ac model. Type III compensator is employed to improve the frequency response and closed loop control of three-phase boost converter. The controller design procedure is discussed in detail. The effect of right-half plane zero in non-minimum phase system and the appropriate pole-zero placements to overcome the maximum phase lag in such system is discussed. The compensated closed loop system is tested for load variations to observe the transient response.
A Novel Approach for Allocation of Optimal Capacitor and Distributed Generati...paperpublications3
Abstract: Distributed generation (DG) units, based on their interfacing technology are divided into synchronous generator interfaced DGs, asynchronous generator interfaced DGs and inverter interfaced DGs. This paper presents two algorithms for allocation of optimal capacitor and distributed generation on radial distribution system. These algorithms predict requirement of reactive vars and real power and supplied via capacitor banks and distributed generation. This arrangement reduces transmission losses and voltage stability problem. Developed algorithm has been implemented on two IEEE 69 nodes and 52 nodes systems.
A novel fuzzy based controller to reduce circulating currents in parallel int...IJECEIAES
This paper exhibits suppression strategy of low frequency circulating current components for parallel inter-leaved converters. Here inverters are parallelized by magnetically coupled inductors. Traditionally, carrier interleaved technique was used to get lower distorted output voltage, but it gives a higher circulating currents to flow through the Two-VSC‘s. The mutual inductance of the coupled inductors (CI) is utilized for minimizing circulating currents of high frequency components. Nevertheless, CI can‘t have capability to riddle the components generated by low frequency. When these circulating currents extremely increases may leads to CI saturation, elevated switching losses and diminishes the entire performance of system. Here author identified a novel control technique for a grid-connected parallel inter-leaved converter depending on approach of energy shaping control (ECS). This controller diminishes the value of the low frequency components of circulating current (LFCC). The performance of the proposed circuit is evaluated in simulation mode and correlated with the conventional proportional integral control (PIC) and the linear quadratic control (LQC). The Fuzzy controller is also included in this work to enhance the converter performance effectively and to diminish the circulating currents along with the healthy harmonic performance analysis.
Particle Swarm Optimization based Network Reconfiguration in Distribution Sys...theijes
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Implementation Of Thyristor Controlled Series Capacitor (TCSC) In Transmissio...IJERA Editor
A grid of transmission lines operating at high or extra high voltages is required to transmit power from
generating stations to load. In addition to transmission lines that carry power from source to load, modern power
systems are highly interconnected for economic reasons. The large interconnected transmission networks are
prone to faults due to the lightning discharges and reduce insulation strength. Changing of loads and atmosphere
conditions are unpredictable factors. This may cause overloading of lines due to which voltage collapse takes
place. These problems can be eased by providing sufficient margin of working parameters and power transfer,
but it is not possible due to expansion of transmission network. Still the required margin is reduced by
introduction of fast dynamic control over reactive and active power by high power electronic controllers. This
paper describes about implementation of Thyristor Controlled Series Capacitor (TCSC) in transmission line
model in order to enhance power flow at the receiving end. The triggering pulses to the thyristor are given using
Arduino.
The high penetration of power electronic based distributed energy resources (DERs) has increased the importance and attention given to voltage security of distribution systems. Voltage control in the electrical power system is critical for a proper operating condition. Therefore, distribution systems must have the ability to maintain a secure voltage profile. Using inverters for Volt/VAR control (VVC) can provide a faster response for voltage regulation than traditional voltage regulation devices, such as transformer load tap changers and voltage regulators. The primary objective of this paper is to demonstrate how smart inverters can be used to eliminate the voltage deviation by solving a mixed-integer quadratic program to determine the amount of reactive power that should be injected or absorbed at the appropriate nodes. The proposed method incorporates capacitor banks connected to the network and determines whether to turn on or off the capacitor bank for voltage regulation. These processes will be demonstrated in several cases that are focused on mitigating voltage-dips and swells.
Optimal Placement of Static Series Voltage Regulator (SSVR) in Distribution S...IJERA Editor
This paper presents optimal placement of Static Series Voltage Regulator (SSVR), for voltage profile improvement and power loss reduction in radial distribution systems under steady state condition. SSVR consists of a series compensator. The series compensator injects the series voltage in quadrature with the branch current in such a way that the receiving end voltage is maintained at desired value (up to 1 p.u). The criteria for selection of optimum location of SSVR are under voltage problem mitigation and loss reduction in the network under steady sate condition. Particle Swam Optimization (PSO) technique is used to find the rating of the device. The proposed model is tested using standard distribution system consisting of 33 nodes
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Modelling and Simulation of Facts Devices TCSC and SVC for A 11 Bus Power Systemijtsrd
Due to the ever increasing demand for power and the growth of the transmission network, transmission lines must now be operated under load, posing a danger of power flow control and voltage instability. This study proposes using TCSC and SVC devices to control power flow in a power system network. The TCSC is a series compensated device that lowers transmission line reactance and improves power flow, whereas the SVC is a shunt compensated device that improves voltage profile. This paper describes a method for modelling and simulation with MATLAB SIMULINK Sim power System block set . For power flow management and voltage stability limit, the appropriate position of TCSC and SVC devices is evaluated. The proposed method is implemented on a two area four machine 11 bus test system model, and the simulated results are shown to validate the test case system. The performance of the TCSC and SVC devices is evaluated in this study, and the simulated results are compared for better power flow regulation in the power system. Vinit K Sharma | Namrata Sant "Modelling and Simulation of Facts Devices (TCSC and SVC) for A 11 Bus Power System" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-5 , August 2022, URL: https://www.ijtsrd.com/papers/ijtsrd50395.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/50395/modelling-and-simulation-of-facts-devices-tcsc-and-svc-for-a-11-bus-power-system/vinit-k-sharma
Reactive Power Compensation and Power Factor Correction by Reactive VAR Compe...ijtsrd
Power factor improvement for nonlinear loads is the point of interest for researchers in recent scenario. Power factor plays a major role in efficiency of electrical system. The Purpose of this paper is to power factor improvement by using proper control strategy. Simulation on MATLAB Simulink environment is conducted with resistive inductive load. The low power factor is highly undesirable as it causes an increase in current, resulting in additional losses of active power in all the elements of power system from power system down to the utilization devices. To compensate reactive power and improve the power factor by using a static VAR compensator, it consisting converter 2 level SCR with capacitor bank. This work deals with the performance evaluation through analytical studies and practical implementation on an existing system consisting of a distribution transformer of 1phase, 50Hz, 230V 12V capacity. Sadi Mujtaba | Neena Godara "Reactive Power Compensation and Power Factor Correction by Reactive VAR Compensator" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-1 , December 2021, URL: https://www.ijtsrd.com/papers/ijtsrd49100.pdf Paper URL: https://www.ijtsrd.com/engineering/electrical-engineering/49100/reactive-power-compensation-and-power-factor-correction-by-reactive-var-compensator/sadi-mujtaba
Three-phase four-wire shunt hybrid active power filter model with model pred...IJECEIAES
This paper presents a harmonic reduction and load imbalance model in a three-phase four-wire distribution network. This model uses a hybrid active power filter, a passive inductor and capacitor filter, and an active power filter in the form of a three-phase, four-leg connected grid inverter. The switching of the voltage source converter on this filter uses finite control set model predictive control (FCS-MPC). Control of this hybrid active power filter uses model predictive control (MPC) with a cost function, comparing the reference current and prediction current with mathematical modelling of the circuit. The reference current is taken from the load current by extracting dq, and the predicted current is obtained from the iteration of the voltage source converter (VSC) switching pattern. Each combination is compared with the reference current in the cost function to get the smallest error used as a power switching signal. Modelling was validated by using MATLAB Simulink. The simulation results prove a decrease in harmonics at a balanced load from 22.16% to 4.2% and at an unbalanced load, reducing the average harmonics to 4.74%. The simulation also decreases the load current imbalance in the distribution network. Reducing the current in the neutral wire from 62.01%-0.42% and 11.29-0.3 A.
Design of 5.1 GHz ultra-low power and wide tuning range hybrid oscillatorIJECEIAES
The objective of the proposed work is to demonstrate the use of a hybrid approach for the design of a voltage-controlled oscillator (VCO) which can lead to higher performance. The performance is improved in terms of the tuning range, frequency of oscillation, voltage swing, and power consumption. The proposed hybrid VCO is designed using an active load common source amplifier and current starved inverter that are cascaded alternatively to achieve low power consumption. The proposed VCO achieves a measured phase noise of -74 dBc/Hz and a figure of merit (FOM) of -152.6 dBc/Hz at a 1 MHz offset when running at 5.1 GHz frequency. The hybrid current starved-current starved VCO (CS-CS VCO) consumes a power of 289 µW using a 1.8 V supply and attains a wide tuning range of 96.98%. Hybrid VCO is designed using 0.09 µm complementary metal– oxide–semiconductor (CMOS) technology. To justify the robustness, reliability, and scalability of the circuit different corner analysis is performed through 500 runs of Monte-Carlo simulation.
A REVIEW ON EVALUATION OF PV MODELS BASED ON AN INTEGRATION USING A NEW CONFI...ijiert bestjournal
The effect of linear imbalances and nonlinear loads on the voltage balance of the neutral-point- clamped converters is described in this paper. The Neutral-Point-Clamped inverters are used in the multilevel inverters for high power application s. In this paper a three level NPC inverter that couple accommodate with solar photovoltaic (PV) and battery storage in grid connected system. The three level space vector modulation technique (SVPWM) is proposed. The SVPWM correct the ac voltage under unbalance dc voltage condition .SV-PWM strategy makes it possible to control the neutral point voltage by optimum choice of switch sequence for any position and length of output voltage vector. The control scheme has capability to control the power delivery between the solar PV,battery,and grid,it simulta neously provides maximum power point tracking (MPPT) operation for the solar PV. The res ults of matlab modeling of the system detail the comparative operation of inverter topologies wh ich are the conventional two level inverters and multilevel inverter topology to reduce total ha rmonic distortions in grid voltage and electromagnetic interference. Three-level NPC volta ge source inverter that can integrate both renewable energy and battery storage on the dc side of the inverter has been presented. The effectiveness of the proposed methodology is invest igated by the simulation of several scenarios,including battery charging and discharging with dif ferent levels of solar irradiation.
Power Factor Improvement in Distribution System using DSTATCOM Based on Unit ...RSIS International
Power factor plays important role in the function of
the power system network. Hence, the power factor
improvement will increase the performance of power system
equipments. This paper presents the design and implementation
of distribution static compensator (DSTATCOM) with the stardelta
transformer for improvement of the power factor in threephase
four wire distribution system in the presence of threephase
linear load in the events of single phase, two-phase and
three phase trippings. The unit vector template method based
control algorithm has been implemented for the control of the
proposed DSTATCOM. The proposed test model has been
simulated in SIMULINK/MATLAB environment. The
simulations results show the effectiveness of proposed algorithm
1 ijaems oct-2015-3-design and development of novel matrix converter performanceINFOGAIN PUBLICATION
Matrix converter is a direct AC-AC converter topology that directly converts energy from an AC source to an AC load without the need of a bulky and limited lifetime energy storage element. Due to the significant advantages offered by matrix converter, such as adjustable power factor, capability of regeneration and high quality sinusoidal input/output waveforms. Matrix converter has been one of the AC–AC topologies that hasreceived extensive research attention for being an alternative to replace traditional AC-DC-AC converters in the variable voltage and variable frequency AC drive applications. In the present paper an indirect space vector modulated matrix converter is proposed. The basic idea of an indirect modulation scheme is to separately apply SVM to the rectification and inversion stages, before combining their switching states to produce the final gating signals. The paper encompasses development of a laboratory prototype of 230V, 250VA three phase to three phase DSP controlled matrix converter fed induction motor drive. The observations and real time testings have been carried out to evaluate and improve the stability of system under various typical abnormal input voltage conditions
Modified SVPWM Algorithm for 3-Level Inverter Fed DTC Induction Motor DriveIJPEDS-IAES
In this paper, a modified space vector pulse width modulation (MSVPWM)
algorithm is developed for 3-level inverter fed direct torque controlled
induction motor drive (DTC-IMD). MSVPWM algorithm simplifies
conventional space vector pulse width modulation (CSVPWM) algorithm for
multilevel inverter (MLI), whose complexity lies in sector/subsector/subsubsector
identification; which will commensurate with number of levels. In
the proposed algorithm sectors are identified as in two level inverter
and subsectors/sub-subsectors are identified by shifting the original reference
vector to sector 1 (S1). This is valid due to the fact that a three level space
vector plane is a composition of six two level space planes, and are
symmetrical with reference to six pivot states. Switching state/sequence
selection is also very important while dealing with SVPWM strategy for
MLI. In the proposed algorithm out of 27 available switching states apt
switching state is selected based on sector and subsector number, such that
voltage ripple is considerably less. To validate the proposed algorithm, it is
tested on a three level neutral point clamped (NPC) inverter fed DTC-IMD.
The performance of the MSVPWM algorithm is analyzed by comparing no
load stator current ripple of the three level DTC-IMD with two level
DTC-IMD. Significant reduction in steady state torque and flux ripple is
observed. Hence, reduced acoustic noise is a distinctive facet of the proposed
method.
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
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UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
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1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
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Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
Connector Corner: Automate dynamic content and events by pushing a buttonDianaGray10
Here is something new! In our next Connector Corner webinar, we will demonstrate how you can use a single workflow to:
Create a campaign using Mailchimp with merge tags/fields
Send an interactive Slack channel message (using buttons)
Have the message received by managers and peers along with a test email for review
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If the “Approve” button is clicked, a Jira/Zendesk ticket is created for the marketing design team
But—if the “Reject” button is pushed, colleagues will be alerted via Slack message
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Speakers:
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Charlie Greenberg, Host
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A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
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Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
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Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
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This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
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Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
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Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
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To Graph or Not to Graph Knowledge Graph Architectures and LLMs
D010432135
1. IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE)
e-ISSN: 2278-1676,p-ISSN: 2320-3331, Volume 10, Issue 4 Ver. III (July – Aug. 2015), PP 21-35
www.iosrjournals.org
DOI: 10.9790/1676-10432135 www.iosrjournals.org 21 | Page
SVC Placement in Unbalanced Distribution Network to Reduce
the Neutral Lines Current and Ohmic Losses Using Intelligent
Optimization Algorithms
Saeed Rezaeian Marjani, Vahid Talavat
(Department of Electrical Engineering, Urmia University, Urmia, Iran)
Abstract: Distribution Network (DN) unbalancing and their unfavorable effects such as energy losses is an
important challenge in electrical engineering. The system unbalancing problem is highly regarded due to
increasing energy costs in DN. In this paper, the use of SVC (Static Var Compensation) is to improve the
unbalancing and reducing the energy losses in DN. To handle power flow procedure, a novel circuit solution is
presented to modeling the DN unbalancing situations. Furthermore, the nominal active and reactive loads in
different phases have been multiplied into a specified value which is defined by the Unbalancing Factor (UF).
Intelligent optimization algorithms such as PSO (Particle Swarm Optimization), CSA (Cuckoo Search
Algorithm) and FA (Firefly Algorithm) are used to optimal sitting and sizing of the SVC with a three terms
objective function, including losses, Neutral Lines Current and SVC installation cost in the distribution
networks. The effect of SVC number installation in DN is evaluated. To demonstrate the effectiveness of the
proposed method, the modified standard IEEE 123 nodes network has been tested. Simulations are carried out
in two options. The results verify the ability of presented method to improve the performance of the unbalance
distribution network significantly.
Keywords: CSA, Energy Losses, FA, Neutral Lines Current, PSO, SVC, Unbalance Distribution network
I. Introduction
Power generated in plants delivers to the electricity consumers through the transmission, sub
transmission and distribution lines. The consumable loads is always non-uniform and is normally unbalanced
due to accidental and un-simultaneous behavior of them in a DN. System unbalance will have adverse effects
such as unbalance three Phase voltages, increase energy losses and occupation feeder capacity in DN [1, 2, 3].
It is clear that the minimum energy loss is obtained in balanced three phase currents situation.
Moreover, in an unbalancing system, returned flow in neutral wire, increases the Ohmic losses in the neutral
conductor and copper and iron losses in distribution transformers [4].
FACTS (Flexible AC Transmission Systems) devices were introduced to increase the capacity of
transmission lines and optimal operation of the power system in the recent years [5].
The custom FACTS devices are unsuitable in size and cost for applications in DN. Some of FACTS
devices are introduced in suitable capacities to use in DN, such as D-STATCOM and SVC [6, 7]. The number,
locations, and ratings of FACTS devices because of installation cost, must be specified carefully to provide the
maximum benefit to the network.
In order to solve load balancing and reactive power compensation introduce the method to use SVCs
with four-wire three-phase loads [8]. A combined reactive power compensation method of a static Var
compensator (SVC) consists of star and delta connected thyristor controlled reactors and a series active filter is
described for unbalanced three-phase four-wire distribution feeders with Harmonic distortion presented in [9].
In [10] a mathematical model proposed for computer simulation and control of a delta-connected SVC to
achieve the purpose of negative-sequence reduction. In [11] introduced Load Compensate in the unbalanced
distributed network by appropriate D-STATCOM design. Determine the appropriate place SVC using genetic
algorithm to meet load unbalancing and network in [3]; some works have been proposed to fix an unbalancing
load and distribution network problems using D-FACTS In the literature.
Recently, many methods based on artificial intelligence have been developed for solving optimal
location of FACTS and D-FACTS devices problems such as tabu search algorithm [12], Particle Swarm
optimization [13, 14], Genetic Algorithm, [15] Gravitational Search Algorithm [16], firefly Algorithm [2],
Differential Evolution Techniques [13].
DN unbalancing Improvement point of view the maximum decreasing of the Neutral lines current
while decreasing the Energy losses by optimal SVC allocation placement distributing networks using three
intelligent algorithm consist of cuckoo search algorithm (CSA), PSO and FA has been discussed in this paper.
2. SVC Placement in Unbalanced Distribution Network to Reduce the Neutral Lines Current…
DOI: 10.9790/1676-10432135 www.iosrjournals.org 22 | Page
The paper is organized as follows. Section 2 explains the model of SVC. In Section 3 intelligent
Optimization Algorithm is presented. In Section 4, The Proposed SVC Placement Algorithm, including the
objective function, The Proposed Method to Modeling the Unbalancing in Distribution Networks and the Four-
Wire Modeling in Distribution Networks Power Flow, is developed. In Section 5, Simulation Results and
Numerical Studies have been reported. Section 6 contains the Effect of the various SVC Number in system
Unbalancing Improvement and Reduction energy Losses according to propped method followed by conclusions.
II. Static Var Compensator (SVC)
SVC is one of various FACTS devices which are connected in parallel to the distribution network
nodes and acts as injection or absorbing Static reactive power source. Basically SVC output changes between
the inductive or capacitive currents to control various parameters such as network nodes voltage. In the simplest
structure SVC consists of a parallel combination of controlled inductor with thyristor valves switches and
capacitor banks. In terms of performance it is like a variable parallel reactance which by controlling the firing
angle of the thyristors becomes a highly responded capable device [17, 18].
Fig. 1: Circuit model of SVC
Fig. 1 shows an equivalent circuit of SVC. The equipollent reactance to controlled inductor through
thyristor can be expressed by:
)2sin()(2
L
L
X
X )1(
SVC equivalent reactance of the parallel combination of thyristor controlled inductors and capacitor
can be obtained by:
LC
LC
Leq
XX
XX
X
))2sin()(2(
)2(
Where, XC is the parallel capacitor reactance and α is the fire angle of the thyristors. Considering (2),
SVC equivalent Susceptance that is a function of angle firing of thyristors is obtained in (3):
LC
CL
eq
XX
XX
B
))2sin()(2(
)3(
According to (3), unlike the capacitor, Susceptance of SVC is a continuous function of the angle fire of
the thyristors [17].
Injection or absorbing of reactive power by SVC using (4) is calculated:
eqSVC BVQ 2
)4(
In (4), V is the voltage of the node that SVC is installed.
III. Intelligent Optimization Algorithms
A comprehensive study carried out to optimal SVC allocation using three different types of intelligent
optimization algorithms. Main objective is reduction Neutral Lines Current and reduction losses, considering
SVC installing cost in network. In this section PSO, CSA and FA optimization Algorithms has been introduced.
3.1 Particle Swarm Optimization (PSO)
PSO is an evolutionary algorithm which was presented in 1995 by Eberhart & Kennedy. This algorithm
has strong global search capability and the ability to solve the different optimization problems in the multi-
dimensional and nonlinear search space [19].
3. SVC Placement in Unbalanced Distribution Network to Reduce the Neutral Lines Current…
DOI: 10.9790/1676-10432135 www.iosrjournals.org 23 | Page
Simplicity, produce high-quality solutions in less time, Similar flexibility for control, stability study of
local and global search space compared with other algorithms, also fast convergence are some advantage of this
algorithm in power system [20].
In this algorithm, the population of people with R unknown parameters are used in optimization. In
other words, each particle represents a solution of the problem and the appropriate amount of each particle the
each iteration is calculated by choice of objective function [21]. Basically, each particle found the best deal by
itself and knows its location (pbest) furthermore each particle knows The best obtained value among all the
particles (gbest) so the direction and rate of movement of each particle based on previous speed and location is
determined by the pbest and gbest . With this amount, the particles are guided in the optimal or near-optimal
solutions. This shift can be shown based on speed changing idea. Position vector and velocity vector of the
particle can be shown with the help of position and velocity of the particle in the d - dimensional search space as
shown Xi = [xi1, xi2… xid] and Vi = [vi1, vi2… vid] [18, 22].
As a result the speed of the particles changes according to (5):
)(2)(1 21
1
k
i
k
i
k
i
k
i
xGbestrandcxPbestrandc
wVV
)5(
In (5), Vi
K
is the speed of the particle in kth iteration, w is Constant weight, c1 and c2 is Acceleration
coefficients that indicate how the particle moves to the best location and best global position, rand is Random
number between 0 and 1, and xi
K
is the position of ith
particle in kth iteration. Considering (5), particles changes
speed the each iteration.
Typically, the particle speed is limited in specified range and the changed position of each particle
calculated according to velocity vector as:
11
k
i
k
i
k
i Vxx )6(
Pseudo code of implementation PSO presented as follows [23]:
Initialization
Parameters and size of the swarm (S);
Randomly initialize particle position and velocities;
For Each particle,
Let pbestid = xid
Calculate f (xid) of each particle;
Calculate gbest, // the best of pbestid;
While (maximum iterations or minimum error criteria is not met) {
For (i=1 to S) {
Calculate the new velocity using (5);
Calculate the new position using (6);
Calculate f (xid) of each particle;
If (f (xid) <f (pbestid))
Pbestid = xid, // Minimization case;
If (f (pbestid) <f (gbestd))
gbestd = pbestd;
}
}
Show the best solution found gbestd;
3.2 Cuckoo search algorithm (CSA)
Cuckoo search algorithm (CSA) is one of the most recently defined algorithms by Yang and Deb [24,
25] where inspired by the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of
other host birds [27].
Two main operations are building the structure of the CSA, (i) a direct search based on Lévy flights,
(ii) a random search based on the probability for a host bird to discover an alien egg in its nest [26], During the
search process, CSA is following three idealized rules: (i) each cuckoo lays one egg at a time, and dump its egg
in randomly chosen nest; (ii) the best nests with better eggs (better solution) will carry over to the next
generations and (iii) available host nests is a constant number, and the egg laid by a cuckoo is discovered by the
4. SVC Placement in Unbalanced Distribution Network to Reduce the Neutral Lines Current…
DOI: 10.9790/1676-10432135 www.iosrjournals.org 24 | Page
host bird with a probability pa ∈ [0, 1]. In this case, the host bird can either throw the egg away or abandon the
nest and build a completely new nest [24, 25].
Pseudo code of implementation Cuckoo Search via lévy flights presented as follows [27]:
Begin
Generation t = 1;
Initialized with random vector values, and initialize parameters NP (Number Population), D;
Evaluate fitness for every individual and determine the best individual with the best objective value;
While (stopping criterion is not met)
Get a Cuckoo randomly by lévy flights;
Evaluate fitness for the cuckoo F;
Choose a nest among n (say, j) randomly;
If (Fi > Fj)
Replace j by the new solution;
End if
A fraction (pa) of worse nests is abandoned and new ones are built;
Keep the best solution;
Rank the solutions and find the current best;
Update the generation number t = t + 1;
End while
End.
In the CSA each solution is shown as egg in a nest, and a cuckoo egg represent a new solution. The
object is to use the potentially better solutions (cuckoos egg) to replace non-dominate solution in the nests.
Similar to many other meta-heuristic search methods, in the initial process, each solution is generated randomly,
The initial population of the host nests is set to best value of each nest Xbestd (d = 1,…, D). The cuckoo
randomly chooses the nest position to lay egg, in other words the next newly generated solution form D
dimension optimization problem is expressed as:
)(1
DrandnstepsizeXX t
d
t
d
(7)
Where in (7) α is a random number generated between [−1, 1], and
)(01.0 d
t
d XbestXstepStepsize (8)
Where
/1
)(
)()(
Drandn
LevyDrandn
Step
(9)
The randn [D] function generates a Gaussian distribution between [1, D]. Levy (λ) obtain from (10)
1
2
)1(
2)
2
1
(
)
2
sin()1(
)(
Levy (10)
Where λ is a constant (1 < λ ≤ 3) and Γ is gamma function. A Lévy flight is a random walk. After
producing the new solution based on above procedure, it will be compared to the Xd
t
, if the introduced objective
function value of the new solution is smaller than the objective function value of Xd
t
, the new solution is
accepted. Otherwise Xd
t
remains as the best solution.
For the newly obtained solution, its lower and upper limits should be satisfied according to [26]:
1
1
t
di
new
di
new
di
t
di
X
LbXifLb
UbXifUb
X (11)
5. SVC Placement in Unbalanced Distribution Network to Reduce the Neutral Lines Current…
DOI: 10.9790/1676-10432135 www.iosrjournals.org 25 | Page
The other part of cuckoo search is to place some nests by constructing a new solution. The egg is
discovered by the host bird by comparing randomly (i.e. probability Pa ∈ [0, 1]). If the host bird discovers the
alien egg, the host bird can either throw the egg away or abandon the nest, and build a completely new this
crossover operator is shown as Follows [24, 28]:
otherwiseX
PrandLbUbrandX
X
t
d
ai
t
ddis
d
)(
(12)
It can be concluded, CSA good converge behavior is related to three control parameters namely cuckoo
nest population size, maximum generation. Optimally setting of these parameters leads to yield better solution
and lesser computational time.
3.3 Firefly Algorithm (FA)
Firefly algorithm (FA) is a novel nature-inspired meta-heuristic and powerful algorithm that solves the
continuous constrained optimization problems. This algorithm was first developed by Xin-She Yang in late
2007 and 2008 at Cambridge University which was based on the social behavior of fireflies [2, 29].
FA uses the three idealized rules. These three rules are given as follows: (a) One firefly is be attracted
to other fireflies with assumption unisexual mode for them; (b) Attractiveness and brightness decrease as their
distance increases. For any two flashing fireflies if there is no brighter one than a particular firefly, it will move
randomly otherwise the less bright one will move towards the brighter one, and (c) Each firefly represents a
solution. Solution quality is specified by firefly brightness Based on the landscape of the objective function [29].
According to above rules, In FA the variation in light intensity, I, and the formulation of the
attractiveness β are two important parameters. In the simplest form and considering a fixed light absorption
coefficient γ, light intensity I, which is the function of distance r, can be expressed as (13):
2
0)( r
eIrI
(13)
Where I0 is the light intensity at r = 0 [2].
As a firefly’s attractiveness is proportional to the light intensity seen by adjacent fireflies, define the
variation of attractiveness β with the distance r by (14):
2
0)( r
er
(14)
Where β0 is the attractiveness at r = 0 [29].
The distance between any two fireflies i and j can be calculated using the Euclidean distance as:
Dd
djdijiij xxxxr 2
,, )( (15)
Where xi,d is the dth
component of the spatial coordinate x of the ith
firefly and D is the dimension of the
problem [2]. Therefore, the movement of firefly i to another more attractive (brighter) firefly j determined by
(16):
i
k
i
k
j
rk
i
k
i xxexx
k
ij
)(
2
0
1
(16)
Where α is the randomization parameter and ξ is a vector of random numbers drawn from a Gaussian
distribution or uniform distribution. [29].
Pseudo code of implementation FA presented as follows [2]:
Begin
Insert the objective function f(x), x=(x1, x2… xd)T
;
Initialize the fireflies population xi, i=1, 2… n;
Determine the light intensity Ii at xi using f (xi);
Set light absorption coefficient γ, randomize coefficient α;
While (t < MaxGeneration)
For i=1: n all n fireflies
For j=1: n
If (Ii < Ij), Move firefly I toward j; end if
6. SVC Placement in Unbalanced Distribution Network to Reduce the Neutral Lines Current…
DOI: 10.9790/1676-10432135 www.iosrjournals.org 26 | Page
Vary attractiveness with distance r via exp [-γr2
];
Evaluate new solutions and update light intensity;
End for j
End for i
Rank the fireflies and find the current global best;
End while
End.
IV. The Proposed SVC Placement Algorithm
In this paper, the SVCs are located to improve the unbalancing situation and ohmic loss reduction in
distribution network. As well an innovative method is proposed to create different unbalancing status in
distribution network. Comprehensive objective function is defined as sum of three terms consist of the total
Neutral Lines Current, active power loss and SVC installation cost. Optimization results have been carried out
with PSO, CSA and FA methods.
4.1 Problem Formulation
The SVC placement problem in DN is formulated as a general objective function to minimize ohmic
losses, Neutral Lines Currents and SVC installation cost. The proposed objective function is given by:
332211 FFFFunctionObjective (17)
Where F1 is the losses in distribution network which is expressed as:
lossesPF 1 (18)
As well as F2 indicates the total Neutral Lines Current as is following:
LINEN
i
TiSiRi IIIF
1
2 (19)
In (19), NLine is lines number of distribution network and IRi, ISi and ITi are the current phasors in
different phases of ith
line.
The annual SVC installation cost in $/kVAr is determined by (20) [30]:
)38.1273051.00003.0(
1
2
3
i
N
i
i QQF
SVC
(20)
Where NSVC is the number of SVCs and Qi is the reactive power capacity of ith
SVC in MVAr.
It should be pointed out that the terms of objective function in (17) have not the same units, thus
Normalized Weight coefficients, β1, β2 and β3 are defined as follows:
lossPmax
1
3
1
(21)
LINEN
i
TiSiRi III
1
maxmaxmax
2
3
1
(22)
)38.1273051.00003.0(3
1
max
1
2
max
3
i
N
i
i QQ
SVC
(23)
Where Pmax loss is the maximum losses, IRimax, ISimax, ITimax are the three-phase lines current in
distribution network without SVCs and Qimax is the nominal SVC reactive power.
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4.2 The Proposed Method to Modeling the Unbalancing in Distribution Networks
The Neutral Lines Current values in unbalanced distribution networks are not neglected. This is
because of the single-phase loads and unequal drawn currents by various phases of load points in the real
distribution network. Furthermore, the non-zero Neutral lines currents increase losses in the networks.
For a more comprehensive study on the unbalanced network, a novel method is used to modeling the
unbalancing situation in distribution network.
For this purpose, in the proposed method, the nominal active and reactive loads in different phases
have been multiplied into a specified value which is defined by the unbalancing factor (UF). The specified
factor, which is shown in (24), is randomly developed in five diverse ranges of 0 to 1, 0.25 to 1, 0.5 to 1, 0.75 to
1 and 0.9 to 1.
9.0,75.0,5.0,25.0,0
)1(
x
rxxFactorgUnbalancin
(24)
Where, r is a random number between 0 and 1.
4.3 The Four-Wire Modeling in Distribution Networks Power Flow
Due to detailed analysis and study of the DNs and calculate the unknown voltage and currents of DN,
the method in [31] has been used. Forasmuch as the mentioned method is used for non-neutral network, the
modified method as in followed.
In order to obtain the lines currents and nodes voltage of the distribution network, four-wire segment of
the DN has been shown in Fig. 2.
In the above section, the relationship between nodes voltage and branches current is obtained from
(25): [32]
Fig. 2: Circuit model of the four-wire line DN
T
S
R
RST
TN
SN
RN
TN
SN
RN
I
I
I
Z
V
V
V
V
V
V
'
'
'
(25)
Where ZRST obtain from (26)
SsSmSm
SmSsSm
SmSmSs
RST
ZzZzZz
ZzZzZz
ZzZzZz
Z (26)
Where, zs and zm are the self-impedance of each line and the mutual-impedance between lines
respectively.
Based on definition, ZS is defined as follows:
mnsnS zzZ 2 (27)
Where, zsn and zmn are the self-impedance of Neutral lines and the mutual-impedance between Neutral
lines and other lines respectively.
In this study Forward-backward power flow has been employed [32].
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V. Simulation Results and Numerical Studies
In order to evaluate the efficiency of the proposed method, the modified standard IEEE 123-node radial
DN illustrated in Fig. 3, has been studied. In this network, the forth wire has been added in lines to modeling the
Neutral lines of distribution networks. The nominal voltage of the outlined networks is 4.16 KV and the
installed SVCs in various phases is differs from 0 to 600 kVAr.
According to the SVC structure, two working modes can be defined for it, voltage control and reactive
power control. In this study has been used reactive power control mode of SVC.
The simulation results are presented in two options with three optimization algorithms such as PSO,
CSA and FA which is the following:
1) Three items objective function with identical weight coefficients for all x values
2) Single item objective function for x=0 and x=0.9
The parameters used for optimization algorithms shown in Tables 1 to 3.
Optimization Process was carried out more than 20 times. Results are given in Tables 4 to 7.
Table 1: PSO parameters
parameter value
Number of Particles 60
Inertia Weight 50
Acceleration constants
C1=1.5
C2=2.5
Maximum Iteration 200
Table 2: CSA parameters
parameter Value
Number of nest 60
Discover rate of alien
eggs
0.25
Levy coefficient, λ 1.25
Maximum Iteration 200
Table 3: FA parameters
parameter Value
Number of Fireflies 60
gamma 1
Initial Beta 0.2
alpha 0.5
Maximum Iteration 200
Fig. 3: The modified standard IEEE 123-node radial distribution system
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5.1 Three Items Objective Function
In this case, the complete form of objective function contains ohmic loss, Neutral Lines Currents and
SVC installation cost has been used and the simulation results illustrate the effects of SVCs installation in three
optimization algorithms.
According to the non-zero Neutral lines current values of lines, the injected reactive powers in various
phases of the SVCs are different.
Based on the unbalancing situation, the x values differs From zero and 0.9, the simulation results has
been presented in Table 4 and 5 in x=0 and x=0.9 respectively.
Table 4: simulation result in x=0
Table 5: simulation result in x=0.9
Without
SVC
With SVC
Optimization Algorithms - PSO CSA FA
SVCs number - 3 3 3
SVC1 -
Location Size (kVAr) Location
Size
(kVAr)
Location
Size
(kVAr)
2
22.02
28.89
42.02
53
86.561
85.862
98.978
60
103.05
111.11
124.50
SVC2 - 1
193.85
186.30
169.48
86
45.897
34.524
55.772
50
116.67
117.71
119.65
SVC3 - 60
104.68
112.66
124.95
76
160.49
175.14
154.15
15
117.03
117.22
117.54
Feeder current of phase R
(A)
973.5 915.96 905.54 918.38
Feeder current of phase S (A) 969.29 910.7 901.82 912.7
Feeder current of phase T
(A)
978.6 920.27 911.39 921.61
Total Neutral Lines
Current(A)
109.58 72.794 77.128 54.216
Loss (kW) 490.02 461.6 424.74 452.7
Cost ($) - 125490 114340 133080
In the above tables the best location and size of SVCs, feeder top current in R, S and T phases, the total
current through the Neutral lines and network loss considering the cost of SVC.
According to Table 4, the total current of Neutral lines with SVCs placement decrease from 1016.9A to
409.67A about 59.7% in FA optimization algorithm. The ohmic Loss decrease from 148.4 kW to 122.81 kW
about 17.24% in FA optimization algorithm.
The simulation results indicate the PSO and FA algorithms use three SVCs and CSA algorithm use two
location for SVCs. Cost of SVCs allocation Point of view, the optimal solution obtained by employing CSA.
Without
SVC
With SVC
Optimization Algorithms - PSO CSA FA
SVCs number - 3 2 3
SVC1 -
Location Size (kVAr) Location
Size
(kVAr)
Location Size (kVAr)
52
97.10
97.65
86.29
86
96.06
83.16
57.16
48
99.25
82.75
117.72
SVC2 - 44
130.16
127.94
168.21
1
100.16
47.79
91.86
76
104.88
92.18
63.28
SVC3 - 77
92.70
78.94
50.50
- - 34
85.51
87.77
81.86
Feeder current of phase
R (A)
534.31 484.12 485.13 484.81
Feeder current of phase S
(A)
557.61 503.41 512.91 504.35
Feeder current of phase
T (A)
504.93 452.73 459.76 453.46
Total Neutral Lines
Current(A)
1016.9 477.78 476.65 409.67
Loss (kW) 148.44 123.19 124.02 122.81
Cost ($) - 118430 60669 103860
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DOI: 10.9790/1676-10432135 www.iosrjournals.org 30 | Page
However, with this amount of investment the total current of Neutral lines decrease about 53.12%. The ohmic
Loss decrease about 16.5%. According to Table 5, the optimum value of main objective function optimization
obtained by CSA. It is observed that reduced the total Neutral lines current about 29.61 % and network loss
about 13.32%, while the annual SVCs installation cost is 114340 dollars.
On the other hand, the total current of Neutral lines with SVCs placement decrease from 109.58A to
54.216A about 50.5% in FA optimization algorithm. The ohmic Loss decrease from 490.02 kW to 452.7 kW
about 7.62% in FA optimization algorithm. The simulation results indicate the PSO, CSA and FA algorithms
use the same number of location of SVCs. Figs. 4 and 5 shown the Neutral lines current values in DN branches,
without and with SVC by employing various optimization algorithms for x=0 and x=0.9 unbalancing situation.
It is observed that the Neutral lines current magnitude improved in the majority branches with placing
SVCs in appropriate nodes of the network.
Fig. 4: Neutral Lines current magnitude with and without SVC in x=0 by applying PSO, CSA, FA
Fig. 5: Neutral Lines current magnitude with and without SVC in x=0.9 by applying PSO, CSA, FA
Performance and convergence comparison of the various optimization algorithms during 200 iteration
and the same initializing populations, is given in Figs 6 to 7.
5.2 Single Item Objective Function
In order to evaluate efficiencies of PSO, CSA and FA methods to Single-terms optimization, Further
consideration, implementation to SVCs allocation based on consist of just losses and just total neutral Lines
current in the x=0 and x=0.9 status. Simulation results are presented in Tables 6 and 7. In Table 6, the loads
values are in high unbalancing situation and single term objective function has been used. The simulation results
show that the PSO algorithm shown minimum loss with SVCs allocation in losses optimization.
Under this condition The PSO and CSA algorithms find three number of SVCs and FA algorithm find
four candidates of SVC places. Furthermore in the Neutral lines current optimization point of view, the FA
11. SVC Placement in Unbalanced Distribution Network to Reduce the Neutral Lines Current…
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algorithm is the best result in the total Neutral lines current minimization. Under this condition The PSO and FA
algorithms find four number of SVCs and CSA algorithm find three candidates of SVC places.
As well as, Table 7, the loads values are in low unbalancing situation has been used.
Fig. 6: PSO, CSA, FA Convergence plot in x=0
Fig. 7: PSO, CSA, FA Convergence plot in x=0.9
Table 6: SVC placement based on Single – terms optimization in x=0
case losses Total Neutral lines current
Optimization
algorithm
PSO CSA FA PSO CSA FA
SVC number 3 3 4 4 3 4
SVC1(location &
number)
67
101.03
102.64
86.39
97
101.39
105.31
88.11
23
77.49
62.47
70.76
30
72.24
72.81
80.97
48
119.47
106.49
139.92
57
69.08
85.95
69.11
SVC2(location &
number)
47
90.96
86.29
109.64
44
45.72
48.55
100.14
62
71.72
94.19
78.01
86
105.07
92.39
63.33
57
107.38
117.59
55.69
48
102.71
84.28
115.98
SVC3(location &
number)
52
57.57
67.23
36.88
13
142.16
118.12
79.50
72
87.34
85.95
67.22
9
75.80
74.31
64.59
67
139.38
123.48
110.05
37
60.43
67.06
70.04
SVC4(location &
number)
- - - 44
84.01
62.45
74.9
48
111.85
85.43
130.07
- - 76
100.72
83.91
57.92
Losses(kW) 122.25 122.37 122.4 123.58 124.23 123.04
Total Neutral Lines
Current(A)
769.41 845.29 767.04 402.73 405.52 403.36
Cost($) 94107 105620 116770 132360 129900 123230
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Table 7: SVC placement based on Single – terms optimization in x=0.9
According to Table 7, losses optimization point of view, the PSO, CSA and FA algorithms find the
same number of location of SVCs. allocation SVCs by employing PSO, CSA and FA algorithms, Leads to the
ohmic losses decrease about 15.04%, 14.96% and 14.92% respectively. However the total neutral lines current
Condition not seems appropriate.
As well as, the total neutral lines current optimization point of view, the CSA and FA algorithms use
three and FA algorithm use two location for SVCs. allocation SVCs by employing PSO, CSA and FA
algorithms, Leads to the total neutral lines current decrease about 51.07%, 53.77% and 50.68% respectively.
However ohmic losses decrease about 4.69%, 14.63% and 7.56% respectively.
To compare between various unbalancing situation where created in a distributing network, Standard
Deviation indicator is presented for three optimization methods. The index indicates rating of current dispersion
through the neutral lines from the average value of currents in two modes by SVC in each five unbalancing
situations.
5,4,3,2,1
)(
1
1 2
1
j
AA
N
SD i
N
i
i
LINE
j
LINE
(28)
Where Ai and Ᾱi obtain by (29):
LINEN
i
i
i
i Ni
CurrentNeutral
CurrentNeutral
A
LINE
,...,1,
1
(29)
LINEN
i
i
i
i
CurrentNeutralAverage
CurrentNeutralAverage
A
1
(30)
Using (30) the results for a different unbalancing situation is shown in Fig. 8.
case losses Total Neutral lines current
Optimization
algorithm
PSO CSA FA PSO CSA FA
SVC number 3 3 3 2 3 3
SVC1(location
& number)
52
199.94
199.95
200
40
189.26
168.10
173.96
67
148.53
142.64
152.81
60
57.317
66.79
78.34
48
119.47
106.49
139.92
15
104.84
105.06
105.34
SVC2(location
& number)
44
157.1
156.75
157.5
8
141.22
183.45
157.8
47
147.83
130.20
129.59
48
116.34
117.90
120.3
57
107.38
117.38
55.69
60
114.27
122.42
135.81
SVC3(location
& number)
67
142.92
143.14
144.17
67
146.80
150.98
151.25
53
116.83
146.67
132.74
-
-
67
139.38
123.49
110.08
42
99.33
100.2
102.23
SVC4(location
& number)
- - - - - - - - - - -
Losses(kW) 416.3 416.7 416.93 467.02 418.33 452.98
Total Neutral
Lines
Current(A)
100.5 134.16 184.56 53.621 50.66 54.04
Cost($) 191340 186410 159000 70966 216150 126080
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Fig. 8: comparison of normalized SD factor for different values of x with PSO, CSA, FA
VI. The Effect of Increasing the Number of SVC in Improvement Unbalancing and
Reduction Losses in the Distribution Network
In order to analysis placed SVC’s number efficacy on the improvement of unbalancing network and
reduction of losses in unbalancing state for x=0 Serve as the worst unbalancing situation for network using PSO,
CSA and FA.
Results have been investigated for 1 to 8 three-phase SVC placement with these algorithms, which is
shown in Fig. 9.
In the case of unbalancing, comparing the total Neutral line current with respect to the value shown in
Fig. 9. It reveals that the increasing the number of SVC’s has not a significant impact on reducing the Neutral
lines current. As well to reduce the losses more than three 3-phases SVC’s can be used which at economic point
of view may not be affordable.
Fig. 9: the Effect of more number of SVC on Neutral lines current and losses reduction with PSO, CSA, FA
VII. Conclusion
In this paper, to distribution network unbalancing improvement point of view reduction Neutral Lines
Current and energy loss, three phase SVC optimal allocation with non-identical values is performed.
A novel method for modeling the unbalanced DN is introduced, so the nominal active and reactive
loads in different phases have been multiplied into a specified value which is defined by the unbalancing factor
(UF).
Simulation results have been carried out on The IEEE Standard 123 node network for five random
unbalance situations. Optimal location, sizing and number of SVC specified using PSO, CSA and FA
algorithms. The simulation results presented in two options: 1) Three items objective function with identical
weight coefficients for all x values, 2) Single item objective function for x=0 and x=0.9, were shows reduction
network unbalancing and network losses with the lowest investment.
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The used optimization algorithms were compared point of view optimal SVCs allocation and
Convergence speed in different UF value under proposed method.
It can be concluded from the simulation results that in point of view of main objective function
optimization and convergence speed, CSA is more efficient in the proposed method. But this does not mean the
performance of the two other algorithms is Inefficient. Because, in point of view of single term analysis of main
objective function and Single item objective function optimization, FA and PSO also have shown better
solution. This paper presented a comprehensive study about efficiency of various optimization algorithms in
proposed method.
In addition, the effect of raising the number of installed SVC’s in network is evaluated on reducing
network unbalancing and losses. So it can be seen usage of the SVC in DNs as an efficient and updated manner
to improve the DNs operation, which will increase the performance of networks efficiently.
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