R. Kazemzadeh; E. Najafi Aghdam; M. Fallah; Y. Hashemi
Volume 2, Issue 2 , December 2014, , Pages 103-112
Abstract
This paper presents a comparative analysis between two current control strategies, constant source power and generalized Fryze current, used in Active Power Filter (APF) applications having three different modulation methods. The Hysteresis Band (HB) and first-order Delta-Sigma Modulation (DSM) as well ...
Read More
This paper presents a comparative analysis between two current control strategies, constant source power and generalized Fryze current, used in Active Power Filter (APF) applications having three different modulation methods. The Hysteresis Band (HB) and first-order Delta-Sigma Modulation (DSM) as well as the second-order DSM is applied. The power section of the active power filter is viewed as an Analogue to Digital Converter (ADC), then as a result a three-phase shunt active filter modulator controller which, uses Delta-Sigma analogue to digital converter is presented to improve modulator performance. As a result, using second-order Delta-Sigma modulator makes low switching rate compared with first-order Delta-Sigma and hysteresis modulators under same sampling frequency. So, applying this modulator increases system efficiency and reduces cost of switches. In addition, simulation results on MATLAB software show that by using the Delta-Sigma modulator, Total Harmonic Distortion (THD) can be significantly decreased. Moreover, active filter based on the second-order DSM with constant source power has high efficiency and provides lower source current THD.
Smart Grid
Hamidreza Arasteh; Mohammadsadegh Sepasian; Vahid Vahidinasab
Volume 3, Issue 2 , December 2015, , Pages 116-130
Abstract
This paper presents a novel concept of "smart distribution system expansion planning (SDEP)" which expands the concept of demand response programs to be dealt with the long term horizon time. The proposed framework, integrates demand response resources (DRRs) as virtual distributed generation (VDG) resources ...
Read More
This paper presents a novel concept of "smart distribution system expansion planning (SDEP)" which expands the concept of demand response programs to be dealt with the long term horizon time. The proposed framework, integrates demand response resources (DRRs) as virtual distributed generation (VDG) resources into the distribution expansion planning. The main aim of this paper is to develop and initial test of the proposed model of SDEP to include DRRs which are one of the most important components to construct smart grid. SDEP is modeled mathematically as an optimization problem and solved using particle swarm optimization algorithm. The objective function of the optimization problem is to minimize the total cost of lines’ installation, maintenance, demand response persuasion, energy losses as well as reliability. Furthermore, the problem is subject to the constraints including radiality and connectivity of the distribution system, permissible voltage levels, the capacity of lines, and the maximum penetration level of demand response. Based on two sample test systems, the simulation results confirmed that the consideration of DRRs simultaneously with distribution system expansion can have economical profit for distribution planners.
Power Electronic
E. Babaei; T. Ahmadzadeh
Volume 4, Issue 2 , December 2016, , Pages 117-131
Abstract
In this paper, a new structure for buck-boost Z-source converter based on Z-H topology is proposed. The proposed converter consists of two LC networks similar to the conventional Z-source and Z-H converters. One of the characteristics of the proposed structure is that, without any changing in its’ ...
Read More
In this paper, a new structure for buck-boost Z-source converter based on Z-H topology is proposed. The proposed converter consists of two LC networks similar to the conventional Z-source and Z-H converters. One of the characteristics of the proposed structure is that, without any changing in its’ power circuit, it can be used in different conversions such as dc/dc, dc/ac and ac/ac. This unique characteristic of the proposed structure is similar to matrix converters. To use this structure in different conversions just control system should be changed. Other main advantages of the proposed converter are simpler topology, step-up and step-down capabilities and low ripple in voltage and current waveforms. Due to capabilities of the proposed converter mentioned above, it can be used in applications such as connect renewable energy sources to the grid, speed control of induction machines, electric vehicles and etc. In this paper, a complete analysis of the proposed converter in dc/dc conversion with details and mathematical equations is presented. Moreover, for the proposed topology, the ripple of inductors and capacitors is given. A suitable control method is presented, too. Also, the power losses and efficiency of the proposed converter are calculated. The correctness operation of the proposed converter is reconfirmed by the experimental results.
H. Shayeghi; A. Rahnama
Abstract
This paper's main purpose is to offer an innovative multistage controller for load-frequency regulation of a standalone interconnected microgrid (SMG). A multistage TDF(FOPI+1) controller is designed, with the first stage being a filter built of the tilting and derivative operators. Transferring the ...
Read More
This paper's main purpose is to offer an innovative multistage controller for load-frequency regulation of a standalone interconnected microgrid (SMG). A multistage TDF(FOPI+1) controller is designed, with the first stage being a filter built of the tilting and derivative operators. Transferring the integrator component to the second stage of the controller and employing its fractional-order (FO) form as a FO proportional-integrator (FOPI) controller results in the latter stage of the controller. To calculate the optimal controller parameters, the recently introduced Bonobo optimization algorithm (BOA) is applied. Besides, the optimization objective function is a mix of the control error signal in each area and the dynamic response characteristics of the system. In complex operating conditions such as sudden changes in power demands, uncertainties in renewable energy units' output, considering nonlinear factors, and parametric uncertainties in a two-area SMG, the performance of the proposed controller is compared with classical and multistage controllers. The results show that the TDF(1+FOPI) controller has a competent dynamic response and can be a suitable choice for performing LFC duties in SMGs. This control strategy's advantages include enhanced controller resistivity in diverse circumstances, faster reaction times, and better dynamic behavior. The results of the five studied scenarios show that using the proposed control strategy, the value of the objective function is improved by an average of more than 50% compared to other classical and conventional controllers. Similarly, improvements of more than 70% and 50% in key integral of time-weighted square error (ITSE) and Integral of absolute error (IAE) time zone indicators, respectively, are among the results of these studies.
Energy Management
M. Ahangari Hassas; K. Pourhossein
Abstract
Hybrid renewable energy systems (HRES) have been introduced to overcome intermittent nature of single-source renewable energy generation. In order to utilize HRES optimally, two issues must be considered: optimal sizing and optimal operation. The first issue has been considered vastly in several articles ...
Read More
Hybrid renewable energy systems (HRES) have been introduced to overcome intermittent nature of single-source renewable energy generation. In order to utilize HRES optimally, two issues must be considered: optimal sizing and optimal operation. The first issue has been considered vastly in several articles but the second one needs more attention and work. The performance of hybrid renewable energy systems highly depends on how efficient the control of energy production is. In this paper, paradigms and common methods available for control and management of energy in HRES are reviewed and compared with each other. At the end, a number of challenges and future research in relation to HRES are addressed.
Micro Grid
A. Marami Dizaji; M. Saniee; K. Zare
Abstract
Resilient operation of microgrid is an important concept in modern power system. Its goal is to anticipate and limit the risks, and provide appropriate and continuous services under changing conditions. There are many factors that cause the operation mode of micogrid changes between island and grid-connected ...
Read More
Resilient operation of microgrid is an important concept in modern power system. Its goal is to anticipate and limit the risks, and provide appropriate and continuous services under changing conditions. There are many factors that cause the operation mode of micogrid changes between island and grid-connected modes. On the other hand, nowadays, electric vehicles (EVs) are desirable energy storage systems (ESSs) because of clean transportation. Besides, energy storage systems are helpful to decrease power generation fluctuations arising from renewable energy sources (RESs) in new power systems. In addition, both sides (EV and RESs’ owners) can gain a good profit by integrating EVs and RESs. Therefore, in this paper, a resilient operation model for microgrid is presented considering disasters and islands from the grid. In the proposed formulation, microgrid (MG) operator schedules its energy resources, EVs and ESSs in minimum cost considering demand response (DR) program and resiliency of the microgrid to islanding and uncertainties in market price, load, and generation of RESs. The impact of uncertainties is modeled in the scenario based framework as stochastic programming. The efficiency of presented method is validated on IEEE standard test system and discussed in two cases.
Power market
S. M. Zabetian-Hosseini; M. Oloomi Buygi
Abstract
Intermittent nature of wind power faced ISO and power producers with new challenges. Wind power uncertainty has increased the required reserve capacity and deployment reserve. Consequently, large-scale wind power generation increases ISO costs and consequently reserve prices. On the other hand, since ...
Read More
Intermittent nature of wind power faced ISO and power producers with new challenges. Wind power uncertainty has increased the required reserve capacity and deployment reserve. Consequently, large-scale wind power generation increases ISO costs and consequently reserve prices. On the other hand, since wind power producers are price taker, large-scale wind power generation decreases residual demand and consequently decreases energy and reserve prices. In this paper, impacts of large-scale wind power generation on energy and reserve markets are studied. To this end, we need to know bids of power producers. But, bids of power producers are unknown and changes if wind power penetration is varied. To overcome this problem, first equilibrium of day-ahead energy market is computed at the presence of large-scale wind power generation considering hour-ahead deployment reserve market scenarios. Then, equilibrium of hour-ahead reserve market is computed considering results of day-ahead market. Finally, impacts of large-scale wind power generation on energy and reserve markets are studied at the markets equilibria. The presented model is applied to an 18-unit power system and the results are analyzed.
P. Venkata; V. Pandya; A.V. Sant
Abstract
This paper proposes a complete diagnostic analysis of faults in a typical modern power system's transmission line using the support vector machine (SVM) with time-series parameters and frequency series parameters as features. The training and testing data of the proposed method are collected by simulating ...
Read More
This paper proposes a complete diagnostic analysis of faults in a typical modern power system's transmission line using the support vector machine (SVM) with time-series parameters and frequency series parameters as features. The training and testing data of the proposed method are collected by simulating all types of faults with all possible variations on a transmission line (TL) in the IEEE-9 bus system using the PSCAD/EMTDC software. While simulating one type of fault, fault resistances and fault inception angles are also varied to account for the various behaviours of the fault. The three-phase instantaneous currents and voltages on both sides of TL are recorded at 32 samples per cycle. A thirty-two sample moving window is used to compute time-series and frequency-series parameters applied as features to the SVM. Ten-fold cross-validation is used to evaluate the performance of the proposed algorithm with evaluation metrics such as accuracy, precision, recall and F1 score. Features generation, training and testing of the proposed method, and performance comparison are done using PYTHON software. The proposed method has achieved an average accuracy of 99.996%, even in the most contaminated environment of 30 dB noise. Compared with the performance of the other popular machine learning algorithms, the proposed method has achieved more accuracy. The performance of the proposed method is also tested with different noise levels, which account for the measurement errors of 30 dB, 35 dB and 40 dB.
Power System Stability
M. Mohammadniaei; F. Namdari; M.R. Shahkarami
Abstract
Voltage stability is one of the most important factors in maintaining reliable operation of power systems. When a disturbance occurs in the power system, it usually causes instabilities and sometimes leads to voltage collapse (VC). To avoid such problems, a novel approach called Vector Analysis (VA) ...
Read More
Voltage stability is one of the most important factors in maintaining reliable operation of power systems. When a disturbance occurs in the power system, it usually causes instabilities and sometimes leads to voltage collapse (VC). To avoid such problems, a novel approach called Vector Analysis (VA) is proposed that exploits a new instability detection index to provide wide area voltage stability for the power systems. The presented index is calculated based on measuring the active and reactive powers that flow through the bus which is connected to the generator bus. Moreover, when the proposed VA approach predicts VC, through disconnecting weak lines and based on network graph, zoning is carried out in the power system. After zoning, damaged and undamaged zones will be differentiated and damaged zones requires load shedding (LS) which is accomplished using ANFIS-TSK (AN-T) intelligent method. The presented approach is applied to the IEEE-39 bus test system. The obtained simulation results demonstrate acceptable performance of the presented approach compared with other suggested methods in terms of speed and accuracy.
N. Kumar; S. Dahiya; K.P. Singh Parmar
Abstract
Economic dispatch (ED) is one of the key problem in power systems. ED tends to minimize the fuel/operating cost by optimal sizing of conventional generators (CG). Greenhouse/toxic gas emission is one of the major problem associated with the CG. Emission dispatch (EMD) deals with the reduction of greenhouse/toxic ...
Read More
Economic dispatch (ED) is one of the key problem in power systems. ED tends to minimize the fuel/operating cost by optimal sizing of conventional generators (CG). Greenhouse/toxic gas emission is one of the major problem associated with the CG. Emission dispatch (EMD) deals with the reduction of greenhouse/toxic gas emissions by the optimal output of generators. The multi-objective economic emission dispatch (MOEED) problem has been formulated by considering both fuel cost and emission objectives. The main objective is optimization of fuel cost and environmental emissions from the CG in a compromised way. In this paper, CONOPT solver in General Algebraic modeling system (GAMS) has been proposed to find the the optimal solutions for ED, EMD, and MOEED problems of a microgrid. The microgrid consists of a wind turbine generator (WTG), a photovoltaic (PV) module, three CGs, and a battery energy storage system (BESS) option. The proposed algorithm has been implemented in four case studies, including all energy sources, without WTG, without PV module, and without renewable energy sources (RES). To establish the effectiveness of the proposed algorithm, it has been compared with various algorithms. The comparison result shows that proposed algorithm is more effective, novel, and powerful. Finally, result shows the effectiveness of proposed approach to optimize the objective function for all aforementioned case studies and the CONOPT solver in GAMS outperformed all the approaches in comparison. The impact of BESS on the operating/fuel cost of the microgrid has also been presented for ED. Paradigm is changing in terms of demand response in µG. Demand flexibility (DF) model has also been established with consumers demand variation in optimization process. Result with DF shows the reduction in cost and better management from demand side.
Renewable Energy
H. Shayeghi; Y. Hashemi
Abstract
In this paper, an optimal design of the renewable combustion plant has been investigated with the aim of ensuring the required load on the Gorgor station. The purpose of this study is to minimize the cost of the proposed hybrid unit during the period of operation of the designed system simultaneously. ...
Read More
In this paper, an optimal design of the renewable combustion plant has been investigated with the aim of ensuring the required load on the Gorgor station. The purpose of this study is to minimize the cost of the proposed hybrid unit during the period of operation of the designed system simultaneously. Information on the intensity of solar radiation and the intensity of wind blowing in the area are taken and applied in the simulation of the system. The intended target function includes the cost of investment, replacement cost and maintenance cost. After the design phase, the main objective is to check the economic benefits of the project's utilization from the grid and compare it with the renewable electricity system, as well as to calculate the initial investment return in renewable electricity. First, the initial cost of consuming electricity from this project is calculated using a renewable electricity system, and then the cost of project is determined using the national grid. Further, by calculating the annual current cost of each of these combinations, the investment return in each mode is obtained. Various options for the use of renewable energies are surveyed separately and in combination. The technical-economic analysis is done on each of these options and ultimately the best one is presented.
Power Electronic
E. Babaei; Gh. Mosatafai Baruji; H. Mashinchi Maheri; A. Abbasnezhad
Abstract
In this paper, a new structure of step-up dc-dc converter by using coupled inductor and active-clamped circuit is proposed. The proposed converter generates high voltage gain in comparison with the conventional dc-dc converters. Duo to using active-clamped circuit in the proposed topology the voltage ...
Read More
In this paper, a new structure of step-up dc-dc converter by using coupled inductor and active-clamped circuit is proposed. The proposed converter generates high voltage gain in comparison with the conventional dc-dc converters. Duo to using active-clamped circuit in the proposed topology the voltage stress on main switch is reduced. In addition the zero voltage switching (ZVS) in ON-state of main switch is obtained. In this paper the performance of the proposed structure is investigated in continues current mode (CCM) and discontinues current mode (DCM). Moreover, the voltage gain in CCM and DCM operations are calculated. To prove the correctness operation and also the given equations, the simulation results in PSCAD/EMTDC software are used.
K. Mazlumi; M. Mohammad Gholiha1; R. Abbasi; F. Mazlumi
Volume 2, Issue 1 , June 2007, , Pages 32-39
Abstract
In this paper, a new method based on branch placement for the optimal positioning of Phasor Measurement Units (PMUs) in power systems is proposed. In this method, the PMUs are in type of single-channel and are installed at the beginning of the branches. Therefore, they are able to measure the bus voltages. ...
Read More
In this paper, a new method based on branch placement for the optimal positioning of Phasor Measurement Units (PMUs) in power systems is proposed. In this method, the PMUs are in type of single-channel and are installed at the beginning of the branches. Therefore, they are able to measure the bus voltages. Also, the installation of the PMUs on the branches increases the security of observability in comparison to the bus placement method at the time of line or PMU outages. In this paper, the Genetic Algorithm (GA) method is used to solve the optimization problem. The proposed method is applied to IEEE 30-bus and 24-bus case study networks. In addition, the method is tested on a real 400 kV network in Iran.
M. Darabian; S. Jalilzadeh; M. Azari
Volume 1, Issue 1 , June 2013, , Pages 33-42
Abstract
This paper focuses on multi-objective designing of multi-machine Thyristor Controlled Series Compensator (TCSC) using Strength Pareto Evolutionary Algorithm (SPEA). The TCSC parameters designing problem is converted to an optimization problem with the multi-objective function including the desired damping ...
Read More
This paper focuses on multi-objective designing of multi-machine Thyristor Controlled Series Compensator (TCSC) using Strength Pareto Evolutionary Algorithm (SPEA). The TCSC parameters designing problem is converted to an optimization problem with the multi-objective function including the desired damping factor and the desired damping ratio of the power system modes, which is solved by a SPEA algorithm. The effectiveness of the proposed controller validates on a multi-machine power system over a wide range of loading conditions. The results of the proposed controller (SPEATCSC) are compared with the Genetic Algorithm (GA) based tuned TCSC through some operating conditions to demonstrate its superior efficiency.
A. Yaqoub Hamza; F.A. Jumaa
Abstract
In this paper, a novel high step-up voltage switching cell formed by four passive elements and three diodes is proposed. The proposed cell can be integrated into a family of boost converters to obtain substantial dc gain as required by an electrical grid supplied such as solar or fuel cell. It is integrated ...
Read More
In this paper, a novel high step-up voltage switching cell formed by four passive elements and three diodes is proposed. The proposed cell can be integrated into a family of boost converters to obtain substantial dc gain as required by an electrical grid supplied such as solar or fuel cell. It is integrated into a boost converter; a new converter is obtained. The features of a new converter are significant dc gain without extreme duty cycle which enables the use of lower voltage and R${}_{Ds-on}$ MOSFET switch so as to reduce cost, the low-stress voltage on the switch and diodes, non-pulsating input current, easiness design and operation, single switch which means easiness of transistor driving, and line-load common ground. In addition, the low-voltage stress across diode allows using Schottky rectifiers to eliminate the reverse recovery current which leads to more reduction in conduction and switching losses. The equations of voltage and current in "continuous conduction mode (CCM) and discontinuous mode (DCM)" are extracted. Moreover, the voltage and current stresses on elements and switch are calculated. Finally, the performance of the proposed converter is validated by simulation results and experimental results to confirm theoretical calculation.
S. Behzadi; A. Bagheri; A. Rabiee
Abstract
Due to the increasing occurrence of natural disasters, importance of maintaining sustainable energy for cities and society is felt more than ever. On the other hand, power loss reduction is a challenging issue of active distribution networks (ADNs). Therefore, the distribution network operators (DNOs) ...
Read More
Due to the increasing occurrence of natural disasters, importance of maintaining sustainable energy for cities and society is felt more than ever. On the other hand, power loss reduction is a challenging issue of active distribution networks (ADNs). Therefore, the distribution network operators (DNOs) should have a certain view on these two problems in today’s smart grids. In this paper, a new convex optimization model is proposed with two objective functions including energy loss reduction in normal operating mode and system load shedding minimization in critical conditions after the occurrence of natural disasters. This purpose is fulfilled through optimal allocation of distributed generation (DG) units from both conventional and renewable types as well as energy storage systems (ESSs). In addition, a new formulation has been derived to form optimal micro-grids (MGs) aiming at energy loss reduction in normal operating condition and resiliency index improvement under emergency situations. The developed model is implemented in GAMS software and the studies have been tested and analyzed on the IEEE 33-bus system. The results verify the effectiveness of the proposed method in terms of energy loss reduction as well as resilience enhancement in extreme operation condition following severe disruptions in the system.
Transformers
V. Behjat; A. Shams; V. Tamjidi
Abstract
Electromagnetic forces in power transformer windings are produced by interaction between the leakage fluxes and current passing them. Since the leakage flux distribution along the windings height is in two axial and radial directions, so the electromagnetic forces have two components, radial and axial. ...
Read More
Electromagnetic forces in power transformer windings are produced by interaction between the leakage fluxes and current passing them. Since the leakage flux distribution along the windings height is in two axial and radial directions, so the electromagnetic forces have two components, radial and axial. There is a risk that a large electromagnetic force due to the short circuit or inrush currents, can cause the windings to be deform, rupture, and/or displace, if the transformer and winding holders structure is not designed or assembled properly. Also, these mechanical changes can damage insulation between two or more adjacent turns of a winding and so, produce the local inter-turn fault. Occurrence of any fault in windings will change the electromagnetic force distribution in transformers and will cause developing secondary faults. Hence, this contribution is aimed at characterizing the electromagnetic forces behavior in power transformers and determines the changes of force values after occurring winding mechanical and inter-turn. The study keeps at disposal a two-winding, three phase, 8 MVA power transformer, on their windings faults are imposed and investigated through the FEM analysis. The accuracy of the created FEM model is firstly validated using analytical methods for transformer healthy condition, and then the winding shorted turn fault along with the mechanical faults are considered using 3D FEM model. The extracted characteristic signatures attained to different type of winding faults is expected to be useful at the design stage of power transformers.
Energy Management
F. Jabari; B. Mohammadi ivatloo; M. B. Bannae Sharifian; H. Ghaebi
Abstract
Nowadays, water and electricity are closely interdependent essential sources in human life that affect socio-economic growth and prosperity. In other words, electricity is a fundamental source to supply a seawater desalination process, while fresh water is used for cooling this power plant. Therefore, ...
Read More
Nowadays, water and electricity are closely interdependent essential sources in human life that affect socio-economic growth and prosperity. In other words, electricity is a fundamental source to supply a seawater desalination process, while fresh water is used for cooling this power plant. Therefore, mutual vulnerability of water treatment and power generation systems is growing because of increased potable water and electricity demands especially during extremely-hot summer days. Hence, this paper presents a novel framework for optimal short-term scheduling of water-power nexus aiming to minimize total seawater desalination and electricity procurement cost while satisfying all operational constraints of conventional thermal power plants, co-producers and desalination units. Moreover, advanced adiabatic compressed air energy storage (CAES) with no need to fossil fuels can participate in energy procurement process by optimal charging during off-peak periods and discharging at peak load hours. A mixed integer non-linear programming (MINLP) problem is solved under general algebraic mathematical modeling system to minimize total water treatment cost of water only units and co-producers, total fuel cost of thermal power plants and co-generators. Ramp up and down rates, water and power generation capacities and balance criteria have been considered as optimization constraints. It is found that without co-optimization of desalination and power production plants, load-generation mismatch occurs in both water and energy networks. By incorporating CAES in water-power grids, total fuel cost of thermal units and co-producers reduce from $1222.3 and $24933.2 to $1174.8 and $24636.8, respectively. In other words, application of CAES results in $343.9 cost saving in benchmark water-power hybrid grid.
Power Electronic
Mohammadreza Banaei
Volume 4, Issue 1 , June 2016, , Pages 42-53
Abstract
This paper proposes a multi-stage power generation system suitable for renewable energy sources, which is composed of a DC-DC power converter and a three-phase inverter. The DC-DC power converter is a boost converter to convert the output voltage of the DC source into two voltage sources. The DC-DC converter ...
Read More
This paper proposes a multi-stage power generation system suitable for renewable energy sources, which is composed of a DC-DC power converter and a three-phase inverter. The DC-DC power converter is a boost converter to convert the output voltage of the DC source into two voltage sources. The DC-DC converter has two switches operates like a continuous conduction mode. The input current of DC-DC converter has low ripple and voltage of semiconductors is lower than the output voltage. The three-phase inverter is a T-type inverter. This inverter requires two balance DC sources. The inverter part converts the two output voltage sources of DC-DC power converter into a five-level line to line AC voltage. Simulation results are given to show the overall system performance, including AC voltage generation. A prototype is developed and tested to verify the performance of the converter.
Power System Operation
R. Sedaghati; F. Namdari
Volume 3, Issue 1 , June 2015, , Pages 47-55
Abstract
One of the significant strategies of the power systems is Economic Dispatch (ED) problem, which is defined as the optimal generation of power units to produce energy at the lowest cost by fulfilling the demand within several limits. The undeniable impacts of ramp rate limits, valve loading, prohibited ...
Read More
One of the significant strategies of the power systems is Economic Dispatch (ED) problem, which is defined as the optimal generation of power units to produce energy at the lowest cost by fulfilling the demand within several limits. The undeniable impacts of ramp rate limits, valve loading, prohibited operating zone, spinning reserve and multi-fuel option on the economic dispatch of practical power systems are scrutinized in this paper. Thus, the proposed nonlinear non-convex formulation is solved by a new modified version of bio-inspired bat algorithm. Due to the complexities associated with the large-scale optimization problem of economic dispatch, adaptive modifications are added to the original bat algorithm. The modification methods are applied at two separate stages and pledge augmentation in convergence rate of the algorithm as well as extricating the algorithm from local optima. Veracity of the proposed methodology are corroborated by performing simulations on three IEEE test systems.
R. Ghanizadeh; A. Jahandideh shendi; M. Ebadian; M. Golkar; A. Ajami
Volume 1, Issue 2 , November 2013, , Pages 110-123
Abstract
In this paper, a novel compensator based on Magnetically Controlled Reactor with Fixed Capacitor banks (FC-MCR) is introduced and then power system stability in presence of this compensator is studied using an intelligent control method. The problem of robust FC-MCR-based damping controller design is ...
Read More
In this paper, a novel compensator based on Magnetically Controlled Reactor with Fixed Capacitor banks (FC-MCR) is introduced and then power system stability in presence of this compensator is studied using an intelligent control method. The problem of robust FC-MCR-based damping controller design is formulated as a multi-objective optimization problem. The multi-objective problem is concocted to optimize a composite set of two eigenvalue-based objective functions comprising the desired damping factor, and the desired damping ratio of the lightly damped and undamped electromechanical modes. The controller is automatically tuned by optimization of an eigenvalue-based multi-objective function using Honey Bee Mating Optimization (HBMO) to simultaneously shift the lightly damped and undamped electromechanical modes to a prescribed zone in the s-plane so that the relative stability is guaranteed and the time domain specifications concurrently secured. The effectiveness of the proposed controller in damping low frequency oscillations under different operating conditions is demonstrated through eigenvalue analysis and nonlinear time simulation studies. The results show that the tuned HBMO-based FC-MCR controller which is designed by using the proposed multi-objective function has an outstanding capability in damping power system low frequency oscillations and significantly improves the power systems dynamic stability.
M. Allahnoori; Sh. Kazemi; H. Abdi; R. Keyhani
Volume 2, Issue 2 , December 2014, , Pages 113-120
Abstract
The microgrid concept provides attractive solutions for reliability enhancement of power distribution systems. Normally, microgrids contain renewable-energy-based Distributed Generation (DG) units, which their output power varies with different environmental conditions. In addition, load demand usually ...
Read More
The microgrid concept provides attractive solutions for reliability enhancement of power distribution systems. Normally, microgrids contain renewable-energy-based Distributed Generation (DG) units, which their output power varies with different environmental conditions. In addition, load demand usually changes with factors such as hourly and seasonal customer activities. Hence, these issues have to be considered in evaluating the reliability of such a power distribution system. This paper evaluates the reliability performance of distribution systems with considering uncertainties in both generation and load demands. The results of applying the proposed approach on a case study system verify its advantages compared to the previous studies.
Distribution Systems
Hossein Shayeghi; Masoud Alilou
Volume 3, Issue 2 , December 2015, , Pages 131-146
Abstract
In this paper, simultaneous placement of distributed generation, capacitor bank and protective devices are utilized to improve the efficiency of the distribution network. The objectives of the problem are reduction of active and reactive power losses, improvement of voltage profile and reliability indices ...
Read More
In this paper, simultaneous placement of distributed generation, capacitor bank and protective devices are utilized to improve the efficiency of the distribution network. The objectives of the problem are reduction of active and reactive power losses, improvement of voltage profile and reliability indices and increasing distribution companies’ profit. The combination of firefly algorithm, particle swarm optimization and analytical hierarchy process is proposed to solve the multi-objective allocation problem. The proposed method is implemented on IEEE 69-bus and also an actual 22-bus distribution systems in Tehran-Iran. Test results approve the effectiveness of the proposed method for improved reliability and network performance of the distribution network.
Power Electronic
A. Baghbany Oskouei; M. R. Banaei; M. Sabahi
Volume 4, Issue 2 , December 2016, , Pages 132-142
Abstract
This paper combines quasi-Z-source into a typical five-level inverter, which includes two dc voltage sources, two quasi-Z-sources and five switching devices. In this structure, the output voltage amplitude is not limited to dc voltage source and it can be increased by quasi-Z-source. Besides, due to ...
Read More
This paper combines quasi-Z-source into a typical five-level inverter, which includes two dc voltage sources, two quasi-Z-sources and five switching devices. In this structure, the output voltage amplitude is not limited to dc voltage source and it can be increased by quasi-Z-source. Besides, due to nature of Z-source families, this new structure is reliable and higher efficiency. Also, in this inverter, two quasi-Z-networks can be controlled independently. This paper also proposes new switching algorithms for proposed five-level dual quasi-Z-Source inverter based on pulse width modulation (PWM) and selective harmonic elimination method (SHEM) algorithms .The performance of proposed inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software and experimental results based PCI-1716 data acquisition system.
Z. K. Gurgi; A. I. Ismael; R. A. Mejeed
Abstract
Solar cell efficiency considers an important part of the PV system, the parameters (Io, IL, n, Rs, and Rsh) of solar cell is the main part that effected on efficiency. The Matlab simulation program was used to estimate the three parameters' optimization values and evaluated by the Fminsearch method, ...
Read More
Solar cell efficiency considers an important part of the PV system, the parameters (Io, IL, n, Rs, and Rsh) of solar cell is the main part that effected on efficiency. The Matlab simulation program was used to estimate the three parameters' optimization values and evaluated by the Fminsearch method, they calculated for solar cells measured from 0oC to 100oC for seven temperatures, then make comparing for the results between the Genetic Algorithm method with Neural Network Algorithm. This paper establishes the results are frequently in GA was better than NNA, with the Io being 3.0992 e-7 and IL being 3.8059 found by GA. GA is good if they have the same population size and number of iterations. The value of the objective function (fval) in GA is 0.002856 but in NNA is 0.005518. And also second objective function (fvaltemp) in GA is 0.1035 with a 0.1069 value in NNA. From the side, the execution time considers in the Fminsearch method is less than NNA and GA that being 64.9 s, 781 s, and 289 s respectively.
