In current study, a method for achieving a load-independent output current with the ability to op... more In current study, a method for achieving a load-independent output current with the ability to optimize the parameter tuning, which is applied to wireless power transfer (WPT) systems, is analyzed. The proposed technique is based on the immittance property in a passive resonant network (PRN) with the purpose of transforming a voltage/current resource into a current/voltage resource. This study determines an immittance conditions-qualified family of PRN, which is associated with a more appropriate topological description in WPT applications. Considering the resource and sink type, a comprehensive specification of the coupling coefficient-based design condition and operating point is carried out. Moreover, the parameters of each proposed topology are reconfigured by adjusting the proportion of active power to reactive power ratios as an index to optimize the topology size as well as a reduction of voltage/current stresses on their elements without changing the specified system-level p...
In a three-phase distribution system, due to unequal distribution of single-phase loads, load div... more In a three-phase distribution system, due to unequal distribution of single-phase loads, load diversities, the different consumption patterns, and growing penetration of renewable energy resources in smart grids, the problem of unbalanced power flow becomes more challenging. In this paper, we propose a new innovative phase imbalance mitigation (PIM) scheme performed by smart meters. With aid of the proposed optimal phase assignment for 3-phase power distribution input feeders known as phase rearrangement (PR), Electrical storages (ES), and the Renewable energy sources (RES), smart meter owners are inspired to assist the distribution system operator (DSO) in diminishing the phase imbalance. This is achieved by employing a proposed connection point assignment system which has the flexibility of selecting the power input among the three phases and management of ESs and RESs. We model this problem into a mixed integer linear program, where smart meter owners minimize their electricity b...
In this paper, we present a new method to determine the optimal location and parameter settings o... more In this paper, we present a new method to determine the optimal location and parameter settings of Unified Power Flow Controller (UPFC) for removing voltage violations and transmission lines overloading. UPFC is considered as the most powerful member of the FACTS devices, that it can control shunt and series power flow. This option gives to UPFC the power to control the voltage profile and transmission lines flow simultaneously. We used the Imperialistic Competitive Algorithm (ICA) to determine the optimal location and optimal parameter settings of UPFC to improve the performance of the power system specially removing voltage violations in the buses and solving transmission lines overloading to increase loadability in the power networks. This procedure is proposed to be applied on IEEE 14 bus system to show the validity of the method.
Nowadays using from wind power plants in power syst em has increased so that in some countries th... more Nowadays using from wind power plants in power syst em has increased so that in some countries thermal generation stations exchanged with wind power plants. SCIG generator is popular to use in power plants. B ecause it is cheap and does not need to extra maintain. Of course cause of working it in fix speed of wind, there is some limitation to use in it. Therefore in location by fspeed of wind, using from SCIG is economic. At this work, a SCIG simulated in MATLAB Simulink and then exercised different value for its rotor resistance and by tak ing its output power and electromagnetic torque, its results compared and its efficiency inv estigated .
Reconfiguration in power systems leads to entry of distributed generation. According to specifica... more Reconfiguration in power systems leads to entry of distributed generation. According to specifications, operating conditions and placement, DG units play an important role in distribution networks. High costs of network development and consequently energy loss and also the quality requirement of distribution network such as voltage sag, unbalance, etc. using DG resources to be considered. Small generation units located close to or in the load centers. One of the most important tasks for electric companies is to supply safe and appropriate electricity to the costumers. In this paper, the prioritization of seven urban areas has been done to install distributed generation using AHP algorithm. Power quality and load growth are the criterion of prioritization. In this study economic factors for DG placement have not been considered. Results are tested on a real medium voltage grid by Digsilent software to verify the efficiency of distributed generation. The results show that DG permits a...
The complex structure of the power system and the pivotal role of electrical energy in determinin... more The complex structure of the power system and the pivotal role of electrical energy in determining the socio-economic indicators of any countries lead the policy makers of power industry to take into account the expansion planning of generation system with high priority. Considering the intense fluctuations of costs in electrical energy generation (particularly due to variation of fuel prices within the recent years in the Middle East), finding an optimal generation portfolio, regardless of the costs variations risk looks impossible. The portfolio theory, as an efficient tool for risk management, provides a proper solution to materialize the optimal generation portfolios with the following properties: maximizing the expected return for any given level of risk, while minimizing risk for every given level of expected return. Determining an optimal generation technologies portfolio in Iran by the above-mentioned theory is the main aim of this study. To do so, two scenarios have been co...
Long interruptions cause no compensable problems to the power systems and decrease the reliabilit... more Long interruptions cause no compensable problems to the power systems and decrease the reliability of the system significantly. One of new technologies that decrease the fault time is Static Transfer Switch (STS) with alternative power supply. In this study an industrial plant with motor loads has been studied with and without use of STS in front of a voltage fault. The simulations have been done to demonstrate the speed of the motors during the faults. As the interruption duration is an important factor in reliability analyzing, some faults with various durations have been applied to the system to study the reliability of the system with and without STS. The results are given to verify the STS efficiency in increasing the system reliability by restoring the motors' speed drop in least time.
Abstract This paper presents a fast and adaptive method to locate faults in three-terminal transm... more Abstract This paper presents a fast and adaptive method to locate faults in three-terminal transmission lines, based on the synchronized measurements within the half-cycle data window. First, the voltage and current data are processed by two sets of half-cycle Fourier filters at three terminals in order to extract the main component of the voltage and current phasors quickly and with a high accuracy using a novel method. The proposed algorithm uses the calculated phasors and works without any need to transmission line’s data or the Thevenin equivalent of the system at each terminal. For making sure of considering the real operation conditions of the network, transmission line’s parameters are determined adaptively using the calculated phasors. The voltage at the tapping point is calculated separately using three-terminal data and consequently the faulty section is identified and then, the precise location of fault in the faulty section is accurately calculated using the nodal current unbalance method. Performance of the proposed algorithm is evaluated under different fault conditions. The simulation results show the high convergence speed and the excellent accuracy of the proposed method under various operating conditions and various fault types.
International Journal of Renewable Energy Development, 2016
Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely... more Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely connected to the low and medium voltage network and created a new structure called micro-grid. Renewable energies (especially wind and solar) based DGs are one of the most important generations units among DG units. Because of stochastic behavior of these resources, the optimum and safe management and operation of micro-grids has become one of the research priorities for researchers. So, in this study, the optimal operation of a typical micro-grid is investigated in order to maximize the penetration of renewable energy sources with the lowest operation cost with respect to the limitations for the load supply and the distributed generation resources. The understudy micro-grid consists of diesel generator, battery, wind turbines and photovoltaic panels. The objective function comprises of fuel cost, start-up cost, spinning reserve cost, power purchasing cost from the upstream grid and the...
Energy consumption is one of the criteria for determining the level and quality of life in a coun... more Energy consumption is one of the criteria for determining the level and quality of life in a country. Continuity of energy supply and long term access to resources needed for a comprehensive energy plan. For this reason, energy planning, the undeniable economic imperative, national and strategic, is considered. In recent years, the production of electricity from wind energy is taken into consideration. Wind turbines are one of the most widely used energy units are in the world. Wind power must be employed in an area that has good potential of wind. The best conditions for installation of wind power are, thus,in remote areas free of obstacles, and consequently with low population density. Reliability benefits, environmental benefits and operating cost savings from wind power integration should be compared with the associated investment costs in order to determine optimum transmission facility for wind power delivery. Determining an adequate transmission system to deliver wind power to a power grid is a difficult problem. Designing a transmission system to match the wind farm's installed capacity can lead to over investment. In this paper, the reliability indices such as: LOLP, LOLE, EENS, using MATLAB software to COPT table in the presence and absence of wind power is calculated and the results compared. Also, the use of these indicators, the economic analysis of the project is done. Because, designing a transmission system to match the wind farms installed capacity can lead to over investment.
2019 International Power System Conference (PSC), 2019
This study presents the Chance-Constrained Optimization (CCO) model to solve the problem of Econo... more This study presents the Chance-Constrained Optimization (CCO) model to solve the problem of Economic Dispatch (ED) and the optimal operation of the energy hub. This problem inherently has a nonlinear nature. To have a tractable model, the proposed model is linearized. Cost minimization is considered as objective function of the problem which is subjected to a suit of constraints. Different flexible elements such as energy storage devices and converters are also considered in the structure of the energy hub. The proposed model is tested on a sample energy hub for one year time horizon. Sensitivity analysis is performed based on the chance-constraint parameters. The results are thoroughly analyzed for the different structures of the energy hub. The results show that considering a well-tuned chance-constraint in the model has a direct impact on the final solution in a cost effective manner.
Abstract Due to importance of duty cycle based model predictive torque control (MPTC), it has bee... more Abstract Due to importance of duty cycle based model predictive torque control (MPTC), it has been accepted as an effective and common alternative control strategy for industry. Since its major drawback is great dependency on duty ratio parameter, the robustness and the complexity of control system has been respectively decreased and increased. A duty-ratio set considering limited members can be replaced with continuous and dependent parameters form duty cycle relationship. Hence, this paper proposes a new and applicable discrete duty cycle control strategy to reduce both the torque and flux ripples appeared in MPTC method. In the proposed method, after preselecting around half of all admissible voltage vectors based on the torque sign or speed variation and the stator flux position, two duty ratios have just been selected for the preselected active voltage vectors. These two duty ratios are achieved based on the equivalent voltage concept with independent motor parameter. Then, the model predictive control method is employed to select the optimum active voltage vector and its relevant duty ratio among the reduced feasible voltage vectors which reduces both the flux and torque ripples, especially in low speed ranges. The simulation results have confirmed the performance of the proposed method in order to reduce the torque and flux ripples, and the experimental results have accordingly validated its performance. Since the number of voltage vectors and duty ratios is significantly decreased, the execution time of the proposed method is further reduced, and virtually worked with a constant switching frequency for all speed ranges.
A framework has been presented in this paper to plan wind unit and distribution static compensato... more A framework has been presented in this paper to plan wind unit and distribution static compensator (DSTATCOM) with an energy storage system (ESS) in the distribution system. This framework is based...
International Journal of Environmental Science and Technology, 2017
In profit-based unit commitment, the objective of programming is to maximize profit and optimize ... more In profit-based unit commitment, the objective of programming is to maximize profit and optimize generation. Practically, the gross profit depends not only on the revenue but also on the total expenditures. In this article, an efficient algorithm is suggested to assess the effect of uncertainties in determining 24-hour optimal strategy of a microgrid (MG) containing wind farms, photovoltaic, fuel cell, combined heat and power units, boiler, and energy storage devices (ESDs). The optimization problem is presented to determine the optimal points for the energy resources generation and to maximize the expected profit considering demand response (DR) programs and uncertainties. The uncertainties include wind speed, photovoltaic power generation (PVPG), market price, power, and thermal load demand. For modeling uncertainties, an effort has been made to predict uncertainties through the hybrid method of wavelet transform (WT)-artificial neural network (ANN)-imperialist competitive algorithm (ICA). In this study, three cases are assessed to confirm the performance of the proposed method. In the first case study, programing MG is isolated from the grid. In the second case study, which is grid-connected mode the WT-ANN-ICA and WT-ANN uncertainties predictions methods are compered. In the third case, which is grid-connected mode the effect of DR programs on the expected profit of energy resources is assessed.
In current study, a method for achieving a load-independent output current with the ability to op... more In current study, a method for achieving a load-independent output current with the ability to optimize the parameter tuning, which is applied to wireless power transfer (WPT) systems, is analyzed. The proposed technique is based on the immittance property in a passive resonant network (PRN) with the purpose of transforming a voltage/current resource into a current/voltage resource. This study determines an immittance conditions-qualified family of PRN, which is associated with a more appropriate topological description in WPT applications. Considering the resource and sink type, a comprehensive specification of the coupling coefficient-based design condition and operating point is carried out. Moreover, the parameters of each proposed topology are reconfigured by adjusting the proportion of active power to reactive power ratios as an index to optimize the topology size as well as a reduction of voltage/current stresses on their elements without changing the specified system-level p...
In a three-phase distribution system, due to unequal distribution of single-phase loads, load div... more In a three-phase distribution system, due to unequal distribution of single-phase loads, load diversities, the different consumption patterns, and growing penetration of renewable energy resources in smart grids, the problem of unbalanced power flow becomes more challenging. In this paper, we propose a new innovative phase imbalance mitigation (PIM) scheme performed by smart meters. With aid of the proposed optimal phase assignment for 3-phase power distribution input feeders known as phase rearrangement (PR), Electrical storages (ES), and the Renewable energy sources (RES), smart meter owners are inspired to assist the distribution system operator (DSO) in diminishing the phase imbalance. This is achieved by employing a proposed connection point assignment system which has the flexibility of selecting the power input among the three phases and management of ESs and RESs. We model this problem into a mixed integer linear program, where smart meter owners minimize their electricity b...
In this paper, we present a new method to determine the optimal location and parameter settings o... more In this paper, we present a new method to determine the optimal location and parameter settings of Unified Power Flow Controller (UPFC) for removing voltage violations and transmission lines overloading. UPFC is considered as the most powerful member of the FACTS devices, that it can control shunt and series power flow. This option gives to UPFC the power to control the voltage profile and transmission lines flow simultaneously. We used the Imperialistic Competitive Algorithm (ICA) to determine the optimal location and optimal parameter settings of UPFC to improve the performance of the power system specially removing voltage violations in the buses and solving transmission lines overloading to increase loadability in the power networks. This procedure is proposed to be applied on IEEE 14 bus system to show the validity of the method.
Nowadays using from wind power plants in power syst em has increased so that in some countries th... more Nowadays using from wind power plants in power syst em has increased so that in some countries thermal generation stations exchanged with wind power plants. SCIG generator is popular to use in power plants. B ecause it is cheap and does not need to extra maintain. Of course cause of working it in fix speed of wind, there is some limitation to use in it. Therefore in location by fspeed of wind, using from SCIG is economic. At this work, a SCIG simulated in MATLAB Simulink and then exercised different value for its rotor resistance and by tak ing its output power and electromagnetic torque, its results compared and its efficiency inv estigated .
Reconfiguration in power systems leads to entry of distributed generation. According to specifica... more Reconfiguration in power systems leads to entry of distributed generation. According to specifications, operating conditions and placement, DG units play an important role in distribution networks. High costs of network development and consequently energy loss and also the quality requirement of distribution network such as voltage sag, unbalance, etc. using DG resources to be considered. Small generation units located close to or in the load centers. One of the most important tasks for electric companies is to supply safe and appropriate electricity to the costumers. In this paper, the prioritization of seven urban areas has been done to install distributed generation using AHP algorithm. Power quality and load growth are the criterion of prioritization. In this study economic factors for DG placement have not been considered. Results are tested on a real medium voltage grid by Digsilent software to verify the efficiency of distributed generation. The results show that DG permits a...
The complex structure of the power system and the pivotal role of electrical energy in determinin... more The complex structure of the power system and the pivotal role of electrical energy in determining the socio-economic indicators of any countries lead the policy makers of power industry to take into account the expansion planning of generation system with high priority. Considering the intense fluctuations of costs in electrical energy generation (particularly due to variation of fuel prices within the recent years in the Middle East), finding an optimal generation portfolio, regardless of the costs variations risk looks impossible. The portfolio theory, as an efficient tool for risk management, provides a proper solution to materialize the optimal generation portfolios with the following properties: maximizing the expected return for any given level of risk, while minimizing risk for every given level of expected return. Determining an optimal generation technologies portfolio in Iran by the above-mentioned theory is the main aim of this study. To do so, two scenarios have been co...
Long interruptions cause no compensable problems to the power systems and decrease the reliabilit... more Long interruptions cause no compensable problems to the power systems and decrease the reliability of the system significantly. One of new technologies that decrease the fault time is Static Transfer Switch (STS) with alternative power supply. In this study an industrial plant with motor loads has been studied with and without use of STS in front of a voltage fault. The simulations have been done to demonstrate the speed of the motors during the faults. As the interruption duration is an important factor in reliability analyzing, some faults with various durations have been applied to the system to study the reliability of the system with and without STS. The results are given to verify the STS efficiency in increasing the system reliability by restoring the motors' speed drop in least time.
Abstract This paper presents a fast and adaptive method to locate faults in three-terminal transm... more Abstract This paper presents a fast and adaptive method to locate faults in three-terminal transmission lines, based on the synchronized measurements within the half-cycle data window. First, the voltage and current data are processed by two sets of half-cycle Fourier filters at three terminals in order to extract the main component of the voltage and current phasors quickly and with a high accuracy using a novel method. The proposed algorithm uses the calculated phasors and works without any need to transmission line’s data or the Thevenin equivalent of the system at each terminal. For making sure of considering the real operation conditions of the network, transmission line’s parameters are determined adaptively using the calculated phasors. The voltage at the tapping point is calculated separately using three-terminal data and consequently the faulty section is identified and then, the precise location of fault in the faulty section is accurately calculated using the nodal current unbalance method. Performance of the proposed algorithm is evaluated under different fault conditions. The simulation results show the high convergence speed and the excellent accuracy of the proposed method under various operating conditions and various fault types.
International Journal of Renewable Energy Development, 2016
Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely... more Nowadays, due to technical and economic reasons, the distributed generation (DG) units are widely connected to the low and medium voltage network and created a new structure called micro-grid. Renewable energies (especially wind and solar) based DGs are one of the most important generations units among DG units. Because of stochastic behavior of these resources, the optimum and safe management and operation of micro-grids has become one of the research priorities for researchers. So, in this study, the optimal operation of a typical micro-grid is investigated in order to maximize the penetration of renewable energy sources with the lowest operation cost with respect to the limitations for the load supply and the distributed generation resources. The understudy micro-grid consists of diesel generator, battery, wind turbines and photovoltaic panels. The objective function comprises of fuel cost, start-up cost, spinning reserve cost, power purchasing cost from the upstream grid and the...
Energy consumption is one of the criteria for determining the level and quality of life in a coun... more Energy consumption is one of the criteria for determining the level and quality of life in a country. Continuity of energy supply and long term access to resources needed for a comprehensive energy plan. For this reason, energy planning, the undeniable economic imperative, national and strategic, is considered. In recent years, the production of electricity from wind energy is taken into consideration. Wind turbines are one of the most widely used energy units are in the world. Wind power must be employed in an area that has good potential of wind. The best conditions for installation of wind power are, thus,in remote areas free of obstacles, and consequently with low population density. Reliability benefits, environmental benefits and operating cost savings from wind power integration should be compared with the associated investment costs in order to determine optimum transmission facility for wind power delivery. Determining an adequate transmission system to deliver wind power to a power grid is a difficult problem. Designing a transmission system to match the wind farm's installed capacity can lead to over investment. In this paper, the reliability indices such as: LOLP, LOLE, EENS, using MATLAB software to COPT table in the presence and absence of wind power is calculated and the results compared. Also, the use of these indicators, the economic analysis of the project is done. Because, designing a transmission system to match the wind farms installed capacity can lead to over investment.
2019 International Power System Conference (PSC), 2019
This study presents the Chance-Constrained Optimization (CCO) model to solve the problem of Econo... more This study presents the Chance-Constrained Optimization (CCO) model to solve the problem of Economic Dispatch (ED) and the optimal operation of the energy hub. This problem inherently has a nonlinear nature. To have a tractable model, the proposed model is linearized. Cost minimization is considered as objective function of the problem which is subjected to a suit of constraints. Different flexible elements such as energy storage devices and converters are also considered in the structure of the energy hub. The proposed model is tested on a sample energy hub for one year time horizon. Sensitivity analysis is performed based on the chance-constraint parameters. The results are thoroughly analyzed for the different structures of the energy hub. The results show that considering a well-tuned chance-constraint in the model has a direct impact on the final solution in a cost effective manner.
Abstract Due to importance of duty cycle based model predictive torque control (MPTC), it has bee... more Abstract Due to importance of duty cycle based model predictive torque control (MPTC), it has been accepted as an effective and common alternative control strategy for industry. Since its major drawback is great dependency on duty ratio parameter, the robustness and the complexity of control system has been respectively decreased and increased. A duty-ratio set considering limited members can be replaced with continuous and dependent parameters form duty cycle relationship. Hence, this paper proposes a new and applicable discrete duty cycle control strategy to reduce both the torque and flux ripples appeared in MPTC method. In the proposed method, after preselecting around half of all admissible voltage vectors based on the torque sign or speed variation and the stator flux position, two duty ratios have just been selected for the preselected active voltage vectors. These two duty ratios are achieved based on the equivalent voltage concept with independent motor parameter. Then, the model predictive control method is employed to select the optimum active voltage vector and its relevant duty ratio among the reduced feasible voltage vectors which reduces both the flux and torque ripples, especially in low speed ranges. The simulation results have confirmed the performance of the proposed method in order to reduce the torque and flux ripples, and the experimental results have accordingly validated its performance. Since the number of voltage vectors and duty ratios is significantly decreased, the execution time of the proposed method is further reduced, and virtually worked with a constant switching frequency for all speed ranges.
A framework has been presented in this paper to plan wind unit and distribution static compensato... more A framework has been presented in this paper to plan wind unit and distribution static compensator (DSTATCOM) with an energy storage system (ESS) in the distribution system. This framework is based...
International Journal of Environmental Science and Technology, 2017
In profit-based unit commitment, the objective of programming is to maximize profit and optimize ... more In profit-based unit commitment, the objective of programming is to maximize profit and optimize generation. Practically, the gross profit depends not only on the revenue but also on the total expenditures. In this article, an efficient algorithm is suggested to assess the effect of uncertainties in determining 24-hour optimal strategy of a microgrid (MG) containing wind farms, photovoltaic, fuel cell, combined heat and power units, boiler, and energy storage devices (ESDs). The optimization problem is presented to determine the optimal points for the energy resources generation and to maximize the expected profit considering demand response (DR) programs and uncertainties. The uncertainties include wind speed, photovoltaic power generation (PVPG), market price, power, and thermal load demand. For modeling uncertainties, an effort has been made to predict uncertainties through the hybrid method of wavelet transform (WT)-artificial neural network (ANN)-imperialist competitive algorithm (ICA). In this study, three cases are assessed to confirm the performance of the proposed method. In the first case study, programing MG is isolated from the grid. In the second case study, which is grid-connected mode the WT-ANN-ICA and WT-ANN uncertainties predictions methods are compered. In the third case, which is grid-connected mode the effect of DR programs on the expected profit of energy resources is assessed.
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