Mojtaba Najafi - Academia.edu (original) (raw)
Papers by Mojtaba Najafi
Scientia Iranica
Abstract. This paper mainly focuses on investigating a stochastic energy management approach to ... more Abstract. This paper mainly focuses on investigating a stochastic energy management approach to enhance reliability of the networked microgrids within a smart island. In this regard, a networked microgrid is considered in the smart island, which is integrated with a multi-energy hub (multi-EH) system aiming to simultaneously support the electrical, thermal, and water demands of the island, isolated from the main grid. The objective function is organized as the cost of operation and reliability of the networked microgrid and is solved using a modified bat algorithm. The uncertainty of stochastic parameters is modelled using the 2-m point estimate method, which has notable advantages in terms of accuracy and simplicity of implementation. Different scenarios are considered both in critical and normal conditions to evaluate the performance of the studied model. Both GAMS and MATLAB software's were employed to study the proposed model. The proposed model improved the reliability of the networked microgrid system and results reveal that the proposed cooperative approach could decrease total operation and investment cost of the networked microgrid by 13%.
International Transactions on Electrical Energy Systems, 2021
This paper presents the optimal and intelligent design of photovoltaic-wind-hydrogen system with ... more This paper presents the optimal and intelligent design of photovoltaic-wind-hydrogen system with the aim of minimizing the overall cost of the system and considering the reliability constraints based on annual radiation and wind speed data in Bushehr city. The hydrogen storage system includes an electrolyzer, a hydrogen storage tank and a fuel cell. Overall costs of hybrid systems include initial investment costs, maintenance and operation and replacement of components, and reliability constraint indicate deficit load demand probability (DLDP). In this study, the decision variables were optimized system capacity including number of solar panels, wind turbine, electrolyzer power capacity, mass of hydrogen storage tank, fuel cell capacity and power transfered with inverter by Grey Wolf Optimization (GWO) algorithm that has high convergence speed and accuracy. System design is presented in different scenarios of hybrid system combinations. To verify the proposed method, the results are...
In this paper maximum power control of wind turbine and induction generator connected with two ba... more In this paper maximum power control of wind turbine and induction generator connected with two back to back voltage source converters to grid are studied. Machine currents are controlled by indirect vector control method. In this method, generator side converter controls the maximum excitation (air gap flux) by machine's d-axis current and controls generator torque by machine's q-axis current. Induction generator speed is controlled by tip speed ratio (TSR) upon the wind speed variations in order to generate the maximum output power. Grid side converter regulates the DC link voltage and injective active power by d-axis current and regulates the injective reactive power by qaxis current using simple control method P-Q. Simulation results show that the proposed method operates correctly.
The short-circuit currents are very important quantity affecting the design of bus systems, groun... more The short-circuit currents are very important quantity affecting the design of bus systems, grounding systems, circuit breakers, substation apparatus, rotating machines and in fact, almost all the aspects of distribution system design. Among those applications, a robust and efficient short-circuitanalysis program is very important for planning and operation of systems. In this paper, a fast and easy programmable short circuit analysis method for unbalanced distribution systems is proposed. Two relationship matrices, the bus-current-injection-to-branch-current matrix are used to represent the special topological characteristics of distribution networks. The proposed short-circuit analysis method is developed from these two matrices and can be used to solve the various types of unsymmetrical faults. Therefore, a computer program by Matlab software has been developed to calculate the short circuit current of unbalanced distribution networks. Simulation results obtained using the proposed technique and a fictitious network (similar to Iran distribution networks) will be presented.
Sādhanā
The growing use of distributed generation (DG) at the distribution level has led to a change in t... more The growing use of distributed generation (DG) at the distribution level has led to a change in the status of distribution networks from a passive network to an active network such as transmission systems. Therefore, transmission network pricing methods such as nodal pricing could be used in the distribution network. DG connection to the distribution network affects bus nodal pricing. If the DG presence reduces losses and congestion in the distribution network, nodal pricing will also decrease. This paper presents a method for calculating the optimal size and place of DG in the distribution network based on nodal pricing. This planning is doing to maximize the profits of distribution companies that have used DG in their network to meet several advantages. The simulation was performing using the improved artificial bee colony algorithm (IABC). In the IABC algorithm, by exchanging the received information between bees according to Newton and gravity laws, it uses all this algorithm capacity to find the ideal answer by considering the constraints applied to the system. In most DG placement articles, network loads are assuming to constant. Because loads are often sensitive to voltage and frequency, constant load analysis leads to inaccurate results. Therefore, in this paper, the proposed method is implementing on a 38-bus radial distribution system with a model of real loads sensitive to the voltage and frequency of the system, including residential, commercial, and industrial loads.
Sādhanā, 2020
Renewable energy-based on virtual power plants (VPPs) has recently attracted considerable attenti... more Renewable energy-based on virtual power plants (VPPs) has recently attracted considerable attention for participating in energy and reserve markets due to the disadvantages of thermal power plants (TPPs). The present paper aims to maximize the VPP profitability in distribution networks including thermal power plants, at minimum load cost, using a mathematical model for implementing the VPP and evaluating its role in the energy and reserve markets. The proposed model includes a series of probabilistic scenarios used to consider the uncertainty of wind/solar generation. Therefore in the first step, the lower bound of the problem, i.e., minimizing demand cost for all the units, should be calculated. It determines the status of VPP units based on the best-case scenarios. Afterward, the problem is cut to calculate the upper bound of the problem which is maximizing the profit of the VPP. The problem is evaluated in two cases: one is the presence of VPP only in the energy market and the other is the simultaneous presence of the VPP in the reserve and energy markets. The computation ends with the convergence of lower and upper bounds of the problem. Since the proposed method uses a piece-wise model of thermal units and the problem has nonlinear equations, Mixed Integer Programming (MIP) used to calculate the contribution of units by utilizing GAMS software. Finally, the VPP profitability calculated for the day-ahead energy and reserve market after determining the method for the participation of power plants in supply at the minimum cost. The proposed method was then applied to a sample system consisting of three thermal plants, three wind farms, two solar farms, and two energy storage systems, considering several situations to examine the impact of the resources and also the resulting profitability in the energy and reserve market. The final step was the analysis of the results.
IEEE Access
This paper presents an energy management method for the interconnected operation of power, heat, ... more This paper presents an energy management method for the interconnected operation of power, heat, Combined Heat and Power (CHP) units to settle the Day-Ahead market in the presence of a demand response program (DRP). A major challenge in this regard is the price uncertainty for DRP participants. First, the definitive model of the problem is introduced from the perspective of the Regional Market Manager (RMM) in order to minimize the total supply cost in the presence of TOU program, which is a type of DRP. Furthermore, a market-oriented tensile model is presented in the form of a combination of overlapping generations (OLG) and price elasticity (PE) formulations to determine the amount of electricity demand in the TOU program. Then, a price uncertainty model of the proposed problem is introduced according to the IGDT risk aversion and risk-taking strategies considering information gap decision theory (IGDT). The above problem is solved through the use of the co-evolutionary particle swarm optimization (C-PSO) algorithm and the proposed model is implemented on a standard seven-unit system for a period of 24 hours. INDEX TERMS Combined heat and power, time of use, diamond's OLG model, price uncertainty, information gap decision theory, co-evolutionary particle swarm optimization.
In this paper, a method is presented to maximize the revenue from price difference due to the pre... more In this paper, a method is presented to maximize the revenue from price difference due to the presence of storage systems in the power system with a high penetration level of wind resources. To account for price changes due to the profitability of price differences, a two-level model is presented that maximizes the earnings from price differences and has been carried out at a low level of market-clearing procedure. The high level uses low-level production prices and adjusts the storage outputs that affect the low-level price. Conversion techniques have been used for single-line programming with respect to system balance constraints. In order to check the performance, the proposed method will be implemented on the IEEE 118 bus test network. Analyzing the results revealed that the proposed method has improved significantly compared with the traditional method and has been able to achieve higher arbitrage income. By applying a two-level model can soften clearly the marginal price by lo...
Journal of Iranian Association of Electrical and Electronics Engineers, 2013
دنك . نيدب هك تسا تردق هكبش رد ديلوت يفداصت تارييغت ندرك ظاحل ،لوا فده تنوم شور و يفداصت هيوست لد... more دنك . نيدب هك تسا تردق هكبش رد ديلوت يفداصت تارييغت ندرك ظاحل ،لوا فده تنوم شور و يفداصت هيوست لدم كي زا روظنم تسا هدش هدافتسا ولراك . هرهب ،مود فده رد تيفرظ صاصتخا دنيآرف رد اهنآ نانيمطا تيلباق و يديلوت ياهدحاو زا يداصتقا يرادرب يم رارق رظندم ،اهروتارنژ هب هريخذ و يژرنا رازاب زاين دروم دريگ . هنيزه رب هولاع ،هطوبرم فده عبات رد ،هريخذ و يژرنا نيمات ياه هنيزه مدع ياه ين هريخذ و يژرنا ليوحت هديدرگ ظاحل ز دنا . يم يداهنشيپ شور ياهيجورخ رد مزلا ياهقوشم داجيا دنيآرف رد دناوت دوش هتفرگ راكب ناگدننك ديلوت نيب . هدننك ديلوت هكارچ دوخ هب ار رازاب زا يرتشيب مهس ،دشاب هتشاد يرتلااب نانيمطا تيلباق هك يا داد دهاوخ صاصتخا . كبش كي يور رب هدش هئرا شور يياراك تسا هدش هئارا نآ جياتن و هتفرگ رارق يبايزرا دروم هنومن ه .
Scientia Iranica, 2021
There is a variety of items which should be taken into consideration by a regional market manager... more There is a variety of items which should be taken into consideration by a regional market manager (RMM). Participants in the market, technical constraint, price variation/reaction, electricity-price uncertainty and types of the applied demand response program are some instances in this regard. One of the demand response programs is Emergency Demand Response Program (EDRP) which is considered in this paper. In the present study, the objective function of the RMM is formulated in a market environment in order to determine the optimal demand, incentive and power purchased with considering some of technical constraints such as incentive limits, demand limits, power purchased and power balance. Co-evolutionary Improved Teaching Learning-Based Optimization (C-ITLBO) is applied to maximize the RMM's profit. Furthermore, determination of the demand level in the EDRP is performed on the basis of a logarithmic model which includes the price elasticity matrix (PEM) is included. The reserve supplied due to Aggregators (AGGs) is also prioritized using the reserve-margin factor (RMF). In addition, information-gap decision theory (IGDT) is applied to model uncertainty in the initial electricity price. The above mentioned items are modeled in a multi-level formulation.
This study proposes a combined operation of the Unified Power Quality Conditioner (UPQC) with win... more This study proposes a combined operation of the Unified Power Quality Conditioner (UPQC) with wind power generation system considering investment cost. The proposed system consists of a series inverter, a shunt inverter, and an induction generator connected in the dc link through a converter. The proposed system can compensate voltage sag and swell, voltage interruption, harmonics, and reactive power in both interconnected mode and islanding mode. The speed of the induction generator is controlled according to the variation of the wind speed in order to produce the maximum output power. The investment cost of proposed system is compared with investment cost of separated use of UPQC and Wind Energy Conversion System (WECS) and the economic saving due to use of proposed system is estimated. The validity of the proposed system is verified by the results of computer simulation.
In this paper maximum power control of wind turbine and Permanent Magnet Synchronous Generator is... more In this paper maximum power control of wind turbine and Permanent Magnet Synchronous Generator is studied. In the proposed system, the generated voltage of the generator is converted into DC voltage through a full-bridge diode rectifier and this voltage is controlled to maximize power of turbine. The grid side inverter is controlled by grid injected active and reactive power control method. Simulation results show that the maximum power is obtained from the turbines correctly for different wind speeds and active and reactive powers are injected to grid appropriately.
Australian Journal of Basic and Applied Sciences, 2011
This paper presents a new algorithm that calculates the available transfer capability (ATC) in de... more This paper presents a new algorithm that calculates the available transfer capability (ATC) in deregulated networks based on a probabilistic approach. Determination of total transfer capability (TTC) is the key component in ATC computation. An optimal power flow (OPF) technique based on the quadratic programming is implemented to evaluate TTCs for different contingency states in an interconnected power system. The time consumed for TTC calculation is one of the most important problems. In this paper, the TTC is calculated offline. Another problem for assessment of ATC in operating condition is the uncertainty in the load levels. The load uncertainty is considered and modeled by a normal distribution function. The advantages of this algorithm are presented by an application to an IEEE 24-Bus system.
SSRN Electronic Journal, 2022
Ain Shams Engineering Journal, 2021
Abstract Value of the lost load (VOLL) is a useful quantity in economical evaluations of power sy... more Abstract Value of the lost load (VOLL) is a useful quantity in economical evaluations of power systems. The VOLL depends on multiple factors such as type of customer, regional economic conditions and demographics, time and duration of outage, and other specific traits of power interruption. The reviewed literatures show that there are still issues which could be considered in estimation of the VOLL, especially for industrial customers. One of the most interesting issues is inclusion of reliability of an industrial plant in estimation of the VOLL. This means that how reliability data of the plant components (failure rates, repair time, etc.) can be incorporated in the studies to provide a probabilistic model for the VOLL and its related quantities. This paper incorporates failure probability in the VOLL estimation of an industrial plant. For this purpose, firstly an estimate for failure rate of the plant components is obtained and secondly, this estimate is applied in failure probability function which is to be incorporated in the VOLL. Results provide a probabilistic model for the VOLL.
There is an increasing trend in consideration of the electricity-supply quality in modern power s... more There is an increasing trend in consideration of the electricity-supply quality in modern power systems. One of the quality-related aspects is the desired level of reliability at the points of electrical-energy consumption or load points. In this regard, the system operator needs to evaluate the impact of system components on the reliability at the considered load points. “Reliability importance” is a quantitative index in order to measure this impact. The reliability importance measure in most of the conventional methods is on the basis of the risk sensitivity analysis. Such an analysis imposes prohibitive computational burden in large power systems. Considering these points, this paper proposes an approach to evaluate the reliability importance which is not suffered from the immense computational burden. The proposed method determines reliability importance of the electrical-energy producers or generators from the consumers or load points perspective in a selected area of the powe...
Electrical Engineering, 2021
Intelligent electric distribution networks compensated with D-STATCOM are active networks in whic... more Intelligent electric distribution networks compensated with D-STATCOM are active networks in which data of terminals is important for better distribution of energy. Similar to all electricity network devices, energy distribution lines in such networks are also subject to transient and steady-state AC faults, e.g., short circuit. Sections of the network in which the fault occurs are separated by relays. In such a condition, fault location and restoring the normal status of the network are important. Fault location in these networks is performed based on synchronous data of two terminals because data of all buses are transmitted to the main bus In this paper, a time-domain equation method (TDEM) is proposed for locating faults on smart distribution grid (SDG) using distributed line model based on time-domain equations. The proposed method locates the point of transient and steady-state fault in SDG considering DGs and compensators. In this paper, the D-STATCOM and wind power plant are considered in SDG. The suggested method does not need the D-STATCOM and DGs model for applying the algorithm. It only uses data of less than half of the cycle for executing the algorithm. The numerical simulation confirms that the proposed fault location method is accurate and it provides a reliable solution for automatic fault location problem in distribution networks.
2021 International Conference on Recent Advances in Mathematics and Informatics (ICRAMI), 2021
In designing engineering systems, definitive solutions can hardly be applied to actual scenarios.... more In designing engineering systems, definitive solutions can hardly be applied to actual scenarios. This issue is mainly originated from production constraints and the environmental conditions of the actual systems under exploitation. Therefore, a small change in the design variables vector may lead to a significant change in the optimal design that minimizes the objective functions. Hence, it is important to develop methods that provide optimal (or even sub-optimal) solutions with less sensitivity to the uncertainty of the design variables. This is the focus of this paper. We present a robust Non-dominated-Sorting Genetic Algorithm II (NSGA-II)-based multi-objective constrained optimization algorithm. To further illustrate the method, the proposed algorithm is used in the robust and constrained optimal design of a sample engineering system. Evaluation of the obtained results shows that multi-objective engineering problems can be solved by the multi-objective robust optimization (MORO) through finding Pareto solutions, so that by changing the problem parameters, the changes of the solutions will be within an acceptable range.
Electrical Engineering, 2021
One of the important factors in the discussion of power transmission is filling the capacity of n... more One of the important factors in the discussion of power transmission is filling the capacity of network lines, which limits the transmission of power and increases the locational marginal price (LMP) in the network. Today, one of the techniques for resolving congestion and reducing LMP is to install DG units in the network, taking into account two factors: place and optimal size of DG based on operating costs and network constraints, all of which depend on the awareness of the capacity of network lines. In this article, in the first step, using the GA-GSF algorithm, identifying the network's weaknesses such as the lines that have reached their maximum capacity, and then by considering three terms and two scenarios condition of the buses connected to the filled lines will be discussed and we review and extract the best places for installing DG on the network. Then, considering the cost of operating DG and applying it to the objective function of the problem, by positively denoting DG profit and reducing line congestion, the optimization problem is solved by GA-GSF algorithm, and finally, the algorithm output including place and optimal size of DG unit in the network is minimized by line congestion and LMP, and DG installation is economically justified. Finally, the proposed algorithm was tested on the IEEE 14-BUS network for seven different DG types, and the results were such that out of these seven DGs, three DGs were able to reduce the total capacity of the network lines to less than the full capacity of the lines and the price of LMP has been raised to the price of UMP, and the other four DGs have managed to lower the price of LMP compared to their cost function.
Scientia Iranica
Abstract. This paper mainly focuses on investigating a stochastic energy management approach to ... more Abstract. This paper mainly focuses on investigating a stochastic energy management approach to enhance reliability of the networked microgrids within a smart island. In this regard, a networked microgrid is considered in the smart island, which is integrated with a multi-energy hub (multi-EH) system aiming to simultaneously support the electrical, thermal, and water demands of the island, isolated from the main grid. The objective function is organized as the cost of operation and reliability of the networked microgrid and is solved using a modified bat algorithm. The uncertainty of stochastic parameters is modelled using the 2-m point estimate method, which has notable advantages in terms of accuracy and simplicity of implementation. Different scenarios are considered both in critical and normal conditions to evaluate the performance of the studied model. Both GAMS and MATLAB software's were employed to study the proposed model. The proposed model improved the reliability of the networked microgrid system and results reveal that the proposed cooperative approach could decrease total operation and investment cost of the networked microgrid by 13%.
International Transactions on Electrical Energy Systems, 2021
This paper presents the optimal and intelligent design of photovoltaic-wind-hydrogen system with ... more This paper presents the optimal and intelligent design of photovoltaic-wind-hydrogen system with the aim of minimizing the overall cost of the system and considering the reliability constraints based on annual radiation and wind speed data in Bushehr city. The hydrogen storage system includes an electrolyzer, a hydrogen storage tank and a fuel cell. Overall costs of hybrid systems include initial investment costs, maintenance and operation and replacement of components, and reliability constraint indicate deficit load demand probability (DLDP). In this study, the decision variables were optimized system capacity including number of solar panels, wind turbine, electrolyzer power capacity, mass of hydrogen storage tank, fuel cell capacity and power transfered with inverter by Grey Wolf Optimization (GWO) algorithm that has high convergence speed and accuracy. System design is presented in different scenarios of hybrid system combinations. To verify the proposed method, the results are...
In this paper maximum power control of wind turbine and induction generator connected with two ba... more In this paper maximum power control of wind turbine and induction generator connected with two back to back voltage source converters to grid are studied. Machine currents are controlled by indirect vector control method. In this method, generator side converter controls the maximum excitation (air gap flux) by machine's d-axis current and controls generator torque by machine's q-axis current. Induction generator speed is controlled by tip speed ratio (TSR) upon the wind speed variations in order to generate the maximum output power. Grid side converter regulates the DC link voltage and injective active power by d-axis current and regulates the injective reactive power by qaxis current using simple control method P-Q. Simulation results show that the proposed method operates correctly.
The short-circuit currents are very important quantity affecting the design of bus systems, groun... more The short-circuit currents are very important quantity affecting the design of bus systems, grounding systems, circuit breakers, substation apparatus, rotating machines and in fact, almost all the aspects of distribution system design. Among those applications, a robust and efficient short-circuitanalysis program is very important for planning and operation of systems. In this paper, a fast and easy programmable short circuit analysis method for unbalanced distribution systems is proposed. Two relationship matrices, the bus-current-injection-to-branch-current matrix are used to represent the special topological characteristics of distribution networks. The proposed short-circuit analysis method is developed from these two matrices and can be used to solve the various types of unsymmetrical faults. Therefore, a computer program by Matlab software has been developed to calculate the short circuit current of unbalanced distribution networks. Simulation results obtained using the proposed technique and a fictitious network (similar to Iran distribution networks) will be presented.
Sādhanā
The growing use of distributed generation (DG) at the distribution level has led to a change in t... more The growing use of distributed generation (DG) at the distribution level has led to a change in the status of distribution networks from a passive network to an active network such as transmission systems. Therefore, transmission network pricing methods such as nodal pricing could be used in the distribution network. DG connection to the distribution network affects bus nodal pricing. If the DG presence reduces losses and congestion in the distribution network, nodal pricing will also decrease. This paper presents a method for calculating the optimal size and place of DG in the distribution network based on nodal pricing. This planning is doing to maximize the profits of distribution companies that have used DG in their network to meet several advantages. The simulation was performing using the improved artificial bee colony algorithm (IABC). In the IABC algorithm, by exchanging the received information between bees according to Newton and gravity laws, it uses all this algorithm capacity to find the ideal answer by considering the constraints applied to the system. In most DG placement articles, network loads are assuming to constant. Because loads are often sensitive to voltage and frequency, constant load analysis leads to inaccurate results. Therefore, in this paper, the proposed method is implementing on a 38-bus radial distribution system with a model of real loads sensitive to the voltage and frequency of the system, including residential, commercial, and industrial loads.
Sādhanā, 2020
Renewable energy-based on virtual power plants (VPPs) has recently attracted considerable attenti... more Renewable energy-based on virtual power plants (VPPs) has recently attracted considerable attention for participating in energy and reserve markets due to the disadvantages of thermal power plants (TPPs). The present paper aims to maximize the VPP profitability in distribution networks including thermal power plants, at minimum load cost, using a mathematical model for implementing the VPP and evaluating its role in the energy and reserve markets. The proposed model includes a series of probabilistic scenarios used to consider the uncertainty of wind/solar generation. Therefore in the first step, the lower bound of the problem, i.e., minimizing demand cost for all the units, should be calculated. It determines the status of VPP units based on the best-case scenarios. Afterward, the problem is cut to calculate the upper bound of the problem which is maximizing the profit of the VPP. The problem is evaluated in two cases: one is the presence of VPP only in the energy market and the other is the simultaneous presence of the VPP in the reserve and energy markets. The computation ends with the convergence of lower and upper bounds of the problem. Since the proposed method uses a piece-wise model of thermal units and the problem has nonlinear equations, Mixed Integer Programming (MIP) used to calculate the contribution of units by utilizing GAMS software. Finally, the VPP profitability calculated for the day-ahead energy and reserve market after determining the method for the participation of power plants in supply at the minimum cost. The proposed method was then applied to a sample system consisting of three thermal plants, three wind farms, two solar farms, and two energy storage systems, considering several situations to examine the impact of the resources and also the resulting profitability in the energy and reserve market. The final step was the analysis of the results.
IEEE Access
This paper presents an energy management method for the interconnected operation of power, heat, ... more This paper presents an energy management method for the interconnected operation of power, heat, Combined Heat and Power (CHP) units to settle the Day-Ahead market in the presence of a demand response program (DRP). A major challenge in this regard is the price uncertainty for DRP participants. First, the definitive model of the problem is introduced from the perspective of the Regional Market Manager (RMM) in order to minimize the total supply cost in the presence of TOU program, which is a type of DRP. Furthermore, a market-oriented tensile model is presented in the form of a combination of overlapping generations (OLG) and price elasticity (PE) formulations to determine the amount of electricity demand in the TOU program. Then, a price uncertainty model of the proposed problem is introduced according to the IGDT risk aversion and risk-taking strategies considering information gap decision theory (IGDT). The above problem is solved through the use of the co-evolutionary particle swarm optimization (C-PSO) algorithm and the proposed model is implemented on a standard seven-unit system for a period of 24 hours. INDEX TERMS Combined heat and power, time of use, diamond's OLG model, price uncertainty, information gap decision theory, co-evolutionary particle swarm optimization.
In this paper, a method is presented to maximize the revenue from price difference due to the pre... more In this paper, a method is presented to maximize the revenue from price difference due to the presence of storage systems in the power system with a high penetration level of wind resources. To account for price changes due to the profitability of price differences, a two-level model is presented that maximizes the earnings from price differences and has been carried out at a low level of market-clearing procedure. The high level uses low-level production prices and adjusts the storage outputs that affect the low-level price. Conversion techniques have been used for single-line programming with respect to system balance constraints. In order to check the performance, the proposed method will be implemented on the IEEE 118 bus test network. Analyzing the results revealed that the proposed method has improved significantly compared with the traditional method and has been able to achieve higher arbitrage income. By applying a two-level model can soften clearly the marginal price by lo...
Journal of Iranian Association of Electrical and Electronics Engineers, 2013
دنك . نيدب هك تسا تردق هكبش رد ديلوت يفداصت تارييغت ندرك ظاحل ،لوا فده تنوم شور و يفداصت هيوست لد... more دنك . نيدب هك تسا تردق هكبش رد ديلوت يفداصت تارييغت ندرك ظاحل ،لوا فده تنوم شور و يفداصت هيوست لدم كي زا روظنم تسا هدش هدافتسا ولراك . هرهب ،مود فده رد تيفرظ صاصتخا دنيآرف رد اهنآ نانيمطا تيلباق و يديلوت ياهدحاو زا يداصتقا يرادرب يم رارق رظندم ،اهروتارنژ هب هريخذ و يژرنا رازاب زاين دروم دريگ . هنيزه رب هولاع ،هطوبرم فده عبات رد ،هريخذ و يژرنا نيمات ياه هنيزه مدع ياه ين هريخذ و يژرنا ليوحت هديدرگ ظاحل ز دنا . يم يداهنشيپ شور ياهيجورخ رد مزلا ياهقوشم داجيا دنيآرف رد دناوت دوش هتفرگ راكب ناگدننك ديلوت نيب . هدننك ديلوت هكارچ دوخ هب ار رازاب زا يرتشيب مهس ،دشاب هتشاد يرتلااب نانيمطا تيلباق هك يا داد دهاوخ صاصتخا . كبش كي يور رب هدش هئرا شور يياراك تسا هدش هئارا نآ جياتن و هتفرگ رارق يبايزرا دروم هنومن ه .
Scientia Iranica, 2021
There is a variety of items which should be taken into consideration by a regional market manager... more There is a variety of items which should be taken into consideration by a regional market manager (RMM). Participants in the market, technical constraint, price variation/reaction, electricity-price uncertainty and types of the applied demand response program are some instances in this regard. One of the demand response programs is Emergency Demand Response Program (EDRP) which is considered in this paper. In the present study, the objective function of the RMM is formulated in a market environment in order to determine the optimal demand, incentive and power purchased with considering some of technical constraints such as incentive limits, demand limits, power purchased and power balance. Co-evolutionary Improved Teaching Learning-Based Optimization (C-ITLBO) is applied to maximize the RMM's profit. Furthermore, determination of the demand level in the EDRP is performed on the basis of a logarithmic model which includes the price elasticity matrix (PEM) is included. The reserve supplied due to Aggregators (AGGs) is also prioritized using the reserve-margin factor (RMF). In addition, information-gap decision theory (IGDT) is applied to model uncertainty in the initial electricity price. The above mentioned items are modeled in a multi-level formulation.
This study proposes a combined operation of the Unified Power Quality Conditioner (UPQC) with win... more This study proposes a combined operation of the Unified Power Quality Conditioner (UPQC) with wind power generation system considering investment cost. The proposed system consists of a series inverter, a shunt inverter, and an induction generator connected in the dc link through a converter. The proposed system can compensate voltage sag and swell, voltage interruption, harmonics, and reactive power in both interconnected mode and islanding mode. The speed of the induction generator is controlled according to the variation of the wind speed in order to produce the maximum output power. The investment cost of proposed system is compared with investment cost of separated use of UPQC and Wind Energy Conversion System (WECS) and the economic saving due to use of proposed system is estimated. The validity of the proposed system is verified by the results of computer simulation.
In this paper maximum power control of wind turbine and Permanent Magnet Synchronous Generator is... more In this paper maximum power control of wind turbine and Permanent Magnet Synchronous Generator is studied. In the proposed system, the generated voltage of the generator is converted into DC voltage through a full-bridge diode rectifier and this voltage is controlled to maximize power of turbine. The grid side inverter is controlled by grid injected active and reactive power control method. Simulation results show that the maximum power is obtained from the turbines correctly for different wind speeds and active and reactive powers are injected to grid appropriately.
Australian Journal of Basic and Applied Sciences, 2011
This paper presents a new algorithm that calculates the available transfer capability (ATC) in de... more This paper presents a new algorithm that calculates the available transfer capability (ATC) in deregulated networks based on a probabilistic approach. Determination of total transfer capability (TTC) is the key component in ATC computation. An optimal power flow (OPF) technique based on the quadratic programming is implemented to evaluate TTCs for different contingency states in an interconnected power system. The time consumed for TTC calculation is one of the most important problems. In this paper, the TTC is calculated offline. Another problem for assessment of ATC in operating condition is the uncertainty in the load levels. The load uncertainty is considered and modeled by a normal distribution function. The advantages of this algorithm are presented by an application to an IEEE 24-Bus system.
SSRN Electronic Journal, 2022
Ain Shams Engineering Journal, 2021
Abstract Value of the lost load (VOLL) is a useful quantity in economical evaluations of power sy... more Abstract Value of the lost load (VOLL) is a useful quantity in economical evaluations of power systems. The VOLL depends on multiple factors such as type of customer, regional economic conditions and demographics, time and duration of outage, and other specific traits of power interruption. The reviewed literatures show that there are still issues which could be considered in estimation of the VOLL, especially for industrial customers. One of the most interesting issues is inclusion of reliability of an industrial plant in estimation of the VOLL. This means that how reliability data of the plant components (failure rates, repair time, etc.) can be incorporated in the studies to provide a probabilistic model for the VOLL and its related quantities. This paper incorporates failure probability in the VOLL estimation of an industrial plant. For this purpose, firstly an estimate for failure rate of the plant components is obtained and secondly, this estimate is applied in failure probability function which is to be incorporated in the VOLL. Results provide a probabilistic model for the VOLL.
There is an increasing trend in consideration of the electricity-supply quality in modern power s... more There is an increasing trend in consideration of the electricity-supply quality in modern power systems. One of the quality-related aspects is the desired level of reliability at the points of electrical-energy consumption or load points. In this regard, the system operator needs to evaluate the impact of system components on the reliability at the considered load points. “Reliability importance” is a quantitative index in order to measure this impact. The reliability importance measure in most of the conventional methods is on the basis of the risk sensitivity analysis. Such an analysis imposes prohibitive computational burden in large power systems. Considering these points, this paper proposes an approach to evaluate the reliability importance which is not suffered from the immense computational burden. The proposed method determines reliability importance of the electrical-energy producers or generators from the consumers or load points perspective in a selected area of the powe...
Electrical Engineering, 2021
Intelligent electric distribution networks compensated with D-STATCOM are active networks in whic... more Intelligent electric distribution networks compensated with D-STATCOM are active networks in which data of terminals is important for better distribution of energy. Similar to all electricity network devices, energy distribution lines in such networks are also subject to transient and steady-state AC faults, e.g., short circuit. Sections of the network in which the fault occurs are separated by relays. In such a condition, fault location and restoring the normal status of the network are important. Fault location in these networks is performed based on synchronous data of two terminals because data of all buses are transmitted to the main bus In this paper, a time-domain equation method (TDEM) is proposed for locating faults on smart distribution grid (SDG) using distributed line model based on time-domain equations. The proposed method locates the point of transient and steady-state fault in SDG considering DGs and compensators. In this paper, the D-STATCOM and wind power plant are considered in SDG. The suggested method does not need the D-STATCOM and DGs model for applying the algorithm. It only uses data of less than half of the cycle for executing the algorithm. The numerical simulation confirms that the proposed fault location method is accurate and it provides a reliable solution for automatic fault location problem in distribution networks.
2021 International Conference on Recent Advances in Mathematics and Informatics (ICRAMI), 2021
In designing engineering systems, definitive solutions can hardly be applied to actual scenarios.... more In designing engineering systems, definitive solutions can hardly be applied to actual scenarios. This issue is mainly originated from production constraints and the environmental conditions of the actual systems under exploitation. Therefore, a small change in the design variables vector may lead to a significant change in the optimal design that minimizes the objective functions. Hence, it is important to develop methods that provide optimal (or even sub-optimal) solutions with less sensitivity to the uncertainty of the design variables. This is the focus of this paper. We present a robust Non-dominated-Sorting Genetic Algorithm II (NSGA-II)-based multi-objective constrained optimization algorithm. To further illustrate the method, the proposed algorithm is used in the robust and constrained optimal design of a sample engineering system. Evaluation of the obtained results shows that multi-objective engineering problems can be solved by the multi-objective robust optimization (MORO) through finding Pareto solutions, so that by changing the problem parameters, the changes of the solutions will be within an acceptable range.
Electrical Engineering, 2021
One of the important factors in the discussion of power transmission is filling the capacity of n... more One of the important factors in the discussion of power transmission is filling the capacity of network lines, which limits the transmission of power and increases the locational marginal price (LMP) in the network. Today, one of the techniques for resolving congestion and reducing LMP is to install DG units in the network, taking into account two factors: place and optimal size of DG based on operating costs and network constraints, all of which depend on the awareness of the capacity of network lines. In this article, in the first step, using the GA-GSF algorithm, identifying the network's weaknesses such as the lines that have reached their maximum capacity, and then by considering three terms and two scenarios condition of the buses connected to the filled lines will be discussed and we review and extract the best places for installing DG on the network. Then, considering the cost of operating DG and applying it to the objective function of the problem, by positively denoting DG profit and reducing line congestion, the optimization problem is solved by GA-GSF algorithm, and finally, the algorithm output including place and optimal size of DG unit in the network is minimized by line congestion and LMP, and DG installation is economically justified. Finally, the proposed algorithm was tested on the IEEE 14-BUS network for seven different DG types, and the results were such that out of these seven DGs, three DGs were able to reduce the total capacity of the network lines to less than the full capacity of the lines and the price of LMP has been raised to the price of UMP, and the other four DGs have managed to lower the price of LMP compared to their cost function.