Research paper
A.T. Alahmad; A. Saffarian; S.G. Seifossadat; S.S. Mortazavi
Abstract
The widespread adoption of microgrids in electric power systems has brought numerous advantages such as decentralized control, reliability, cost-effectiveness, and environmental benefits. However, one of the most critical challenges faced by islanded microgrids is ensuring frequency and voltage stability. ...
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The widespread adoption of microgrids in electric power systems has brought numerous advantages such as decentralized control, reliability, cost-effectiveness, and environmental benefits. However, one of the most critical challenges faced by islanded microgrids is ensuring frequency and voltage stability. This paper addresses these stability issues that arise when microgrids operate independently, disconnected from the main network through the point of common coupling (PCC). These microgrids rely on renewable resources like photovoltaic (PV) systems, wind turbines, and energy storage systems, which often require DC to AC conversion through inverters to simulate synchronous generators. To overcome the frequency and voltage stability challenges, this research utilizes the droop control technique to regulate the active and reactive power of distribution generators (DGs). The droop control technique is implemented and simulated using MATLAB software, specifically employing a multi-DC bus-based inverter. The simulation results demonstrate that the DGs successfully supply the required total power to meet load demands while maintaining frequency and voltage stability. Through the droop control technique, active and reactive power sharing is achieved, ensuring stability at nominal values. The DGs can effectively maintain a constant power profile at desired values, even in the presence of static and dynamic loads.
Research paper
Power System Operation
N. Kumar; S. Dahiya; K.P.Singh Parmar
Abstract
The microgrid (μG) is an integration of distributed generation and local loads with energy storage system. Cost minimization is one of the main objectives in modern power systems.Economic dispatch(ED) is a fundamental problem related to μG and the conventional grid. Economic dispatch(ED) provides ...
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The microgrid (μG) is an integration of distributed generation and local loads with energy storage system. Cost minimization is one of the main objectives in modern power systems.Economic dispatch(ED) is a fundamental problem related to μG and the conventional grid. Economic dispatch(ED) provides the optimal output of generators in order to reduce the total operating cost. Emission dispatch (EMD) is one of the other major problems associated with CG. The emission dispatch (EMD) solution provides the optimal generator operation to reduce harmful pollutants for a specific load demand. Multi-objective economic emission dispatch (MEED) provides a compromise between ED and EMD. In this paper, two test systems have been proposed. Test system one consists of Six CG. Static ED, EMD, and MOEED analysis has been provided for test system one. Test system two consists of four CG, One wind turbine generator (WTG), and one photovoltaic module (PVM).This paper intends to provide sensitivity analysis and uncertainty regarding the curtailment cost of RES. CPLEX solver in GAMS has been proposed to optimize the three fundamental problems. Comparative study and sensitivity analysis show optimal results, and the GAMS solver provides a more comprehensive framework. Reduction in cost due to uncertainty in ED is 9.58% as compared to 9.7% for test system two. The cost has been reduced in MEED by 9.33% as compared to 9.46%. MEED comparison shows the increment in cost of 2.66 %, but the emission is reduced by 18.98 % for test system two.
Research paper
Electric Mechinces & Drive
Sh. Yadav; S.K. Mallik; A. Mishra
Abstract
Low Switching-based v/f -controlled induction motor (IM) drives are incredibly susceptible to torque harmonics and their Vibrations. These consequences lead to intensifying losses, damage drive, and can even turn out into shaft failure of high power/speed drives. In literature, numerous control ...
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Low Switching-based v/f -controlled induction motor (IM) drives are incredibly susceptible to torque harmonics and their Vibrations. These consequences lead to intensifying losses, damage drive, and can even turn out into shaft failure of high power/speed drives. In literature, numerous control algorithm based on pulse width modulation (PWM) has been reported for low switching-based IM drive. Nowadays, standard PWM techniques (Sinusoidal PWM (S-PWM), selective harmonic elimination (SHE) PWM) are being used as the solution in low-switching IM drives. In this manuscript, the proposed synchronous reference frame (SRF) based P-PWM scheme is analytically evaluated to minimise the torque harmonics and its vibration in low switching IM drive. In this paper, a specific case of four switching angles per quarter cycle (Sq=4) is considered in which the optimized switching angles are obtained while maintaining the quarter wave symmetry (QWS) and half wave symmetry (HWS) nature of the waveform. The proposed approach is validated on 1hp IM drive and compared with S-PWM and SHE-PWM with respect to torque spectrum and vibration under No Load and different loading conditions. Real-time waveforms are recorded using the SRF-based P-PWM technique and the TYPHOON-HIL hardware setup to demonstrate the superior performance of the SRF-based P-PWM in comparison to S-PWM and SHE-PWM, in terms of lower torque harmonics and their vibrations.
Research paper
Power Electronic
H. Chaudhari; P. Darji
Abstract
Recent grid codes require a high voltage direct current (HVDC) converter station remains connected and provide reliable operation under various faults. An improved clamp-double submodule (CD-SM) is introduced in this article, which belongs to the modular multilevel converter (MMC) topologies proposed ...
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Recent grid codes require a high voltage direct current (HVDC) converter station remains connected and provide reliable operation under various faults. An improved clamp-double submodule (CD-SM) is introduced in this article, which belongs to the modular multilevel converter (MMC) topologies proposed for high voltage direct current (HVDC) systems. The proposed submodule (SM) topology features a reduced number of control switches, lower converter level faults, and DC fault-blocking capability compared to the conventional submodule topologies. A CD-SM consists of five $IGBT$s, two diodes, and two floating capacitors, where capacitor voltages are maintained according to the binary geometric propagation (GP) ratio which enables it to generate a maximum four-level output voltage. The hybrid pulse width modulation (PWM) technique is used to generate desired switching pulses for a converter and the associated voltage balancing control technique maintains the power exchange between the converters. In this article, the dimensioning of the proposed MMC converter, and its performance under different fault conditions is discussed in detail. Further, a quantitative comparison with other submodule topologies in terms of dc fault-blocking capability, output voltage level, and device count is discussed. Simulation in MATLAB/Simulink and their results validate the effectiveness of the proposed topology for MMC based HVDC system.
Research paper
Planing & Reliability
A. Ghaedi; M. Mahmoudian; R. Sedaghati
Abstract
In recent years, due to rising social welfare, the reliability has become one of most important topics of modern power network and electricity companies try to provide the electric power to the consumers with minimal interruptions. For this purpose, the electricity companies to improve the reliability ...
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In recent years, due to rising social welfare, the reliability has become one of most important topics of modern power network and electricity companies try to provide the electric power to the consumers with minimal interruptions. For this purpose, the electricity companies to improve the reliability of the power system can utilize different techniques. In this paper, new developments occurred in electricity industry including integration of large-scale renewable resources, integration of large capacity energy storage systems, integration of combined heat and electricity units into power network and demand side response plans are taken into account, and these events impact on power network reliability is assessed. Power networks are affected with integration of renewable resources. Multi-state reliability models for renewable generation plants are obtained, in the paper. Suitable number of states in the proposed reliability model is selected by calculating XB index. Besides, fuzzy c-means clustering approach is utilized for determining probability of states. For study impact of energy storage systems with large capacity on power network reliability, load model is modified. To investigate effect of combined heat and power plants on power network reliability, failure of composed elements and produced thermal power are considered in reliability model of these plants. To evaluate demand side response impact on reliability of power network, the load model is modified. The effectiveness of the proposed techniques on the reliability enhancement of power network is satisfied using numerical results performed on reliability test systems based on the suggested methods.
Research paper
Power System Stability
F. Babaei; A. Safari; J. Salehi; H. Shayeghi
Abstract
Although the presence of clean energy resources in power systems is required to reduce greenhouse gas emissions, system security faces severe challenges due to its increased intelligence and expansion, as well as the high penetration of renewable energy resources. According to new operating policies, ...
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Although the presence of clean energy resources in power systems is required to reduce greenhouse gas emissions, system security faces severe challenges due to its increased intelligence and expansion, as well as the high penetration of renewable energy resources. According to new operating policies, power systems should withstand subsequent single contingencies. Also, the effect of electrical and structural characteristics must be considered in power system security assessment. Thus, this paper introduces a comprehensive risk-based approach that quantifies the impact of contingency-induced variation in topology by using complex network theory metrics. Then, it identifies elements that surpass security limitations and eliminates them to execute cascading outage analysis via AC power flow. Lastly, wind power uncertainty and contingency probability are multiplied by the linear combination of electrical and structural consequences, and security status is assigned to each contingency based on its risk value. Additionally, simulations are carried out on modified 118 and 300 bus IEEE systems, and the extensive results are utilized to demonstrate the effectiveness of the proposed methodology.
Research paper
Distribution Systems
P. Niranjan; N.K. Choudhary; N. Singh; R.K. Singh
Abstract
Conventional overcurrent protection schemes may not be sufficient to provide the complete protection of microgrids, especially in the islanded mode (ISM) of operation. Directional overcurrent relays (DOCRs) in microgrid may malfunction due to significant changes in fault current level and change in topology ...
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Conventional overcurrent protection schemes may not be sufficient to provide the complete protection of microgrids, especially in the islanded mode (ISM) of operation. Directional overcurrent relays (DOCRs) in microgrid may malfunction due to significant changes in fault current level and change in topology from grid-connected mode (GCM) to ISM. The novel contribution of this study is to determine the optimal settings of time-voltage-current-based dual-setting DOCRs with mixed inverse characteristics, valid in both GCM and ISM, without any miscoordination of relay pairs. The relay coordination problem is formulated as a mixed integer non-linear programming (MINLP) problem and optimally solved using an improved environmental adaption method (IEAM). The proposed relay coordination scheme has been tested on a 7-bus microgrid, the low-voltage section of the modified IEEE-14 bus benchmark system. The performance of the proposed protection scheme has been compared with the existing schemes, considering conventional DOCRs, time-voltage-current-based DOCRs, and dual-setting DOCRs.
Research paper
Distribution Systems
F. Jabari; M. Shabanzadeh; M. Zeraati
Abstract
Distribution system state estimation (DSSE) is widely used for real-time monitoring of power grids, where different types of metering devices such as phasor measurement units, smart meters, power quality meters, and etc. are installed. The accuracy of estimated states and the system observability level ...
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Distribution system state estimation (DSSE) is widely used for real-time monitoring of power grids, where different types of metering devices such as phasor measurement units, smart meters, power quality meters, and etc. are installed. The accuracy of estimated states and the system observability level depends on the type, number and location of meters and since there are many nodes and branches in such large networks, a highly redundant measurement infrastructure is practically unattainable due to the limited investment budget. Hence, this paper proposes a novel meter placement algorithm aiming to minimize the distribution system state estimation error and enhance the system observability level considering the limited number of available meters or investment cost. To this end, on one hand, Monte Carlo simulation (MCS) is applied to a weighted least squares (WLS) based DSSE to find the nodal voltage magnitude and angle as the state variables under the uncertainty of measurements. A MCS and WLS-DSSE hybrid iterative nonlinear optimization mesh adaptive direct search (NOMADS) algorithm is proposed to obtain the best locations of the voltage measuring units considering a trade-off between the DSSE performance and the investment cost. The uncertainties associated with the voltage measurements are modeled using random errors with normal probability distribution function. The efficiency and applicability of the proposed method are analyzed by its implementation on a 25-node unbalanced radial distribution system and numerical results demonstrate that this method technically outperforms other heuristic algorithms in the literature which are usually computationally intractable or more demanding in finding the optimal meter places under uncertainties. Compared to other recently developed algorithms, the accuracy of the estimated states as well as the runtime of the proposed algorithm are improved significantly especially under severe measuring errors. Moreover, it is capable to find the minimum number of voltage meters ensuring that the system observability criterion and the expected DSSE accuracy are fulfilled under the uncertain operating conditions.
Research paper
Electric Mechinces & Drive
N. Rostami; A.A. Kadhim; M.B. Bannae-Sharifian
Abstract
Permanent Magnet Linear Synchronous Motors (PMLSMs) suffer from inevitable cogging force, especially in low-speed applications. In this paper, a new PMLSM is presented that uses segmented magnets instead of typically used rectangular magnets. This results in a significant reduction in cogging force and ...
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Permanent Magnet Linear Synchronous Motors (PMLSMs) suffer from inevitable cogging force, especially in low-speed applications. In this paper, a new PMLSM is presented that uses segmented magnets instead of typically used rectangular magnets. This results in a significant reduction in cogging force and improved back EMF waveform. However, with these types of magnets, the actual three-dimensional (3D) structure of the machine cannot be reduced to a 2D problem because the thickness of the magnets varies with the depth of the device. Although 3D Finite Element Analysis (FEA) can be used, this method is very time-consuming even for one calculation step, which makes it difficult to use in optimization processes. To overcome these challenges, quasi-3D approach is used to transform the actual 3D structure of the machine into several 2D models and find the overall performance by combining the results obtained for each 2D problem. Genetic algorithm combined with quasi-3D method is used to find the appropriate thickness of each PM segment.
Research paper
Power System Stability
V.M. Dholakiya; B.N. Suthar
Abstract
This research verifies Frequency-Linked Pricing (FLP)-based operating strategies under an availability-based tariff (ABT) for automatic generation control (AGC) of multisource power systems with nonlinearity and interconnections via AC/DC Tie-Lines. Through modeling and simulation in Matlab/Simulink, ...
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This research verifies Frequency-Linked Pricing (FLP)-based operating strategies under an availability-based tariff (ABT) for automatic generation control (AGC) of multisource power systems with nonlinearity and interconnections via AC/DC Tie-Lines. Through modeling and simulation in Matlab/Simulink, this study also identifies a comparatively superior and more appropriate FLP-based operating strategy for AGC under ABT. Different ABT operating techniques yield Generating Control Error (GCE) by combining unscheduled interchange (UI) charges corresponding to frequency deviation and the marginal cost of generation. Three FLP-based operating strategies are compared to standard operating strategies. In addition, several load pattern scenarios are analyzed to ensure a suitable FLP-based operational strategy. The economic accounting associated with UI pricing for FLP-based operational strategies has been analyzed. The outcomes demonstrate that the operational approach that compares actual UI charges and marginal expenses to their respective reference values excels relatively well.
Research paper
Power Electronic
N. Yousefi; D. Mirabbasi; B. Alfi; M. Salimi; Gh.R. Aghajani
Abstract
This report develops a high step-up topology employing a voltage multiplier cell (VMC) and a coupled inductor for renewable energy usage. The efficiency is improved and the blocking voltage on semiconductors is decreased. The proposed structure achieves a high voltage gain by utilizing a VMC and one ...
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This report develops a high step-up topology employing a voltage multiplier cell (VMC) and a coupled inductor for renewable energy usage. The efficiency is improved and the blocking voltage on semiconductors is decreased. The proposed structure achieves a high voltage gain by utilizing a VMC and one coupled inductor. This structure employs only one MOSFET switch, lowering the cost of the converter. Further benefits are the reduced number of components and the low blocking voltage of the switches/diodes. Furthermore, the VMC functions as a clamp circuit, reducing the peak voltage of the switch. Consequently, in the presented converter, a low nominal voltage MOSFET can be operated. The switching modes, steady-state analysis, and comparative study with other comparable converters demonstrate the converter's performance and superiority. A 200W laboratory scale operating under the 25kHz switching frequency and a voltage conversion of 20V~150V is built to validate the theoretical equations. The proposed converter efficiency at the full load is about 96.3%. Also, the normalized maximum voltage stress on switch and diodes for duty cycle D=0.6 and turn ratio N=2 is about 0.33 and 0.8, respectively.
Research paper
M. Khodsuz
Abstract
In this paper, a novel approach for detecting islanding events in distribution networks special for synchronous generator type is presented. The proposed method leverages information derived from negative sequence voltage components, synchronous generator field voltage, positive sequence impedance variation ...
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In this paper, a novel approach for detecting islanding events in distribution networks special for synchronous generator type is presented. The proposed method leverages information derived from negative sequence voltage components, synchronous generator field voltage, positive sequence impedance variation rate, voltage harmonic distortion factor, and features extracted through wavelet transform applied to voltage waveforms. In order to establish a robust classification system without the necessity of explicit threshold determination, a pattern recognition method is employed. The dataset derived from these characteristics undergoes training using multi-layer support vector machines and a random forest optimization algorithm, resulting in five distinct classes. The study incorporates experimental samples encompassing various scenarios such as symmetric and asymmetric fault occurrences, load variations at different points, capacitor bank switching, variable load switching, nonlinear load switching, and islanding on a modified 34-bus IEEE network. The proposed islanding detection method demonstrates its effectiveness in distinguishing electrical islanding from power quality phenomena such as voltage oscillation, voltage sag, voltage swell, and dynamic voltage changes. Conducted simulations in MATLAB validate the efficacy of the proposed method.
Review paper
Electric Mechinces & Drive
M. Megrini; A. Gaga; Y. Mehdaoui
Abstract
Utilizing electric vehicles (EVs) in place of conventional vehicles is now necessary to lower carbon dioxide emissions, provide clean energy, and lessen environmental pollution. Numerous researchers are trying to figure out how to make these electric vehicles better in order to address this. Electric ...
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Utilizing electric vehicles (EVs) in place of conventional vehicles is now necessary to lower carbon dioxide emissions, provide clean energy, and lessen environmental pollution. Numerous researchers are trying to figure out how to make these electric vehicles better in order to address this. Electric motors and batteries are necessary parts of electric cars. As such, the development of these vehicles was associated with the development of these two entities. This review lists all of the sophisticated electric machines, their control schemes, and the embedded systems that are utilized to put these schemes into practice. Due to this review, we determined out, the induction motor and permanent magnet synchronous motor have been demonstrated to be the most efficient and suitable alternative for propulsion drive in electric vehicles. Furthermore, because torque and speed can be controlled simultaneously with minimal noise and ripples, the FOC approach continues to be the ideal control method. This evaluation offers comprehensive information regarding the application of various control measures. Whereas the model- based design technique made it easier for engineers to program, validate, and fine-tune the system’s controllers before deploying it in the field, STM32 and DSP320F28379 are the best embedded systems for implementation because of their low cost and compatibility with the SIMULINK environment.
Research paper
Power System Control
V.K. Peddiny; B. Datta; A. Banerjee
Abstract
Changes in the electric supply can significantly affect electronic devices since they are very sensitive. Due to a nonlinear system with multiple interconnected and unpredictable demands in the smart grid, the electricity system is facing several issues, including power quality, reactive power management, ...
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Changes in the electric supply can significantly affect electronic devices since they are very sensitive. Due to a nonlinear system with multiple interconnected and unpredictable demands in the smart grid, the electricity system is facing several issues, including power quality, reactive power management, and voltage drop. To address these problems, a static synchronous compensator (STATCOM) is frequently used to compensate and correct the voltage level at the power bus voltage. In this study, an Artificial Neural Network (ANN) and GWO based controlled STATCOM has been developed to replace the traditional PI based controller and enhance the overall STATCOM performance. The ANN controller is preferred due to its simplicity, adaptability, resilience, and ability to consider the non-linearities of the power grid. To train the classifier offline, data from the PI controller was utilized. The MATLAB/Simulink software was employed to assess the effectiveness of STATCOM on a 25 Km transmission line during increased load and three faults. The combined results of the PI and ANN controllers indicate that the ANN controller significantly improves STATCOM efficiency under different operating conditions. Moreover, the ANN controller outperforms the traditional PI controller in terms of results.
Research paper
Electric Mechinces & Drive
D.M. Sonje; R. Munje
Abstract
Fault detection and classification (FDC) is a vital area in the health monitoring of three-phase induction machines. According to the failure survey of three three-phase induction machines, bearing-related faults cause a percentage of motor failures in the range of almost 41-50% which is very significant. ...
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Fault detection and classification (FDC) is a vital area in the health monitoring of three-phase induction machines. According to the failure survey of three three-phase induction machines, bearing-related faults cause a percentage of motor failures in the range of almost 41-50% which is very significant. These faults may occur one or multiple at a time in the bearing. With a well-designed fault detection method, failure of the motor can be reduced and productivity can also be increased. This paper proposes the simultaneous bearing fault detection and classification in three three-phase induction machine using the combination of feature fusion method and intelligent random forest (RF) algorithm. The paper contributes in two folds. In the first part of the paper, the performance of traditional methods such as vibration and current analysis is tested in which statistical parameters obtained from current and vibration signals are passed separately to the intelligent random forest classifier. In the second part of the paper, statistical parameters obtained from current and vibration signals are fused together and used as inputs to the RF classifier. The accuracy and various other performance measures are calculated and based on experimental results; a remarkably high detection/classification performance is achieved.
Research paper
Electric Mechinces & Drive
H. Zaimen; A. Rezig; S. Touati
Abstract
Voltage source inverters (VSIs) based on insulated-gate bipolar transistors (IGBTs) may face various faults that can affect the operation and safety of the entire electric drive system. To enhance the reliability of the drive system, it is crucial to develop an accurate fault diagnosis (FD) method and ...
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Voltage source inverters (VSIs) based on insulated-gate bipolar transistors (IGBTs) may face various faults that can affect the operation and safety of the entire electric drive system. To enhance the reliability of the drive system, it is crucial to develop an accurate fault diagnosis (FD) method and increase fault tolerance control (FTC) capabilities. This paper provides a novel FTC strategy for IGBT open circuit fault (OCF) in induction motor (IM) drives. The proposed FTC strategy includes a fault diagnosis algorithm and inverter reconfiguration. A three-phase current-based diagnosis method (FD) is adopted in this research, where the average absolute value of the normalized currents is used to extract fault detection variables. The developed FD method does not need any extra sensors and provides fast diagnosis time, which is equivalent to almost 25-30% of the phase current’s fundamental cycle. To accomplish satisfactory post-fault operation of the IM drive, a four-leg inverter topology is employed. Finally, the effectiveness of the proposed fault-tolerant drive and diagnosis method is proven through various simulation results.
Research paper
Distribution Systems
N. Kumar; D.K. Jain
Abstract
The integration of distributed generations (DGs) can disrupt the distribution system's radial configuration, leading to potential coordination issues with the existing protection scheme. Disparate operating modes of microgrids render traditional protection schemes ineffective and insecure. This highlights ...
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The integration of distributed generations (DGs) can disrupt the distribution system's radial configuration, leading to potential coordination issues with the existing protection scheme. Disparate operating modes of microgrids render traditional protection schemes ineffective and insecure. This highlights the need for alternative approaches to ensure the reliability and security of microgrids. To mitigate the relay coordination problem in microgrids, this paper puts forth a solution in the form of an adaptive protection scheme. The proposed method is based on fault current and integrates the use of adaptive numerical directional overcurrent relays (ANDOCRs). The proposed adaptive protection strategy encompasses a microgrid central protection controller (MCPC) equipped with communication capabilities. This feature enables MCPC to communicate with intelligent field electronics devices (IFEDs). The MCPC receives data from the IFEDs and updates the ANDOCRs' settings according to the operation mode. This paper suggests a modified objective function specifically tailored to tackle the nonlinear optimization problem for relay coordination in microgrids to strengthen the coordination between primary and backup relays. The proposed adaptive protection scheme also incorporates a quick online fault detection algorithm to identify the faulty feeder precisely. The proposed method is assessed for its performance using a highly unbalanced IEEE-13 node distribution system in MATLAB/Simulink.
Research paper
Power Electronic
S. Hasanzadeh; S.M. Dehghan; M. Asadi; S.M. Salehi
Abstract
Step-up DC-DC converters are essential components used in a wide range of applications. Many researchers have proposed various methods to achieve high voltage gain in DC-DC converters. However, this typically involves adding multiple passive components, which increases system complexity and complicates ...
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Step-up DC-DC converters are essential components used in a wide range of applications. Many researchers have proposed various methods to achieve high voltage gain in DC-DC converters. However, this typically involves adding multiple passive components, which increases system complexity and complicates output voltage control. Maintaining a constant output voltage at the desired value is critical in these converters despite the load, supply voltage changes, and circuit disturbance. Recently, a snubber-less high-step-up enhanced super-lift converter has been developed as a possible solution to these issues. This converter offers high gain without high voltage stress or snubber losses. A model of the converter was created using the state-space averaging technique and is presented in this paper. The control strategy proposed uses the input current in the inner loop and the output voltage in the outer loop. The paper also includes simulation and experimental results that validate the circuit analysis equations.
Research paper
Micro Grid
A. Nargeszar; A. Ghaedi; M. Nafar; M. Simab
Abstract
In recent years, the local feeding of the required loads in the micro grids has received much attention comparing to the extension of the large fuel-based power plants, which require the development of costly transmission lines. On the other hand, environmental constraints have led to the increasing ...
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In recent years, the local feeding of the required loads in the micro grids has received much attention comparing to the extension of the large fuel-based power plants, which require the development of costly transmission lines. On the other hand, environmental constraints have led to the increasing development of renewable energy sources that can generate electricity in the form of small-scale generation units in micro grids. In this study, an appropriate mixture of renewable sources incorporating the wind turbines, current type tidal generation units and the photovoltaic systems is integrated to the micro grid connected to the energy storage systems. The proposed micro grid can be customized in the coastal regions and islands for supplying required loads. To optimally determine capacity and size of renewable power plants, different metaheuristic algorithms are applied, and among them, the particle swarm optimization methodology is used to minimize cost function of the system including the investment, operation and the reliability costs. To calculate reliability cost of micro grid, variable hazard rate of the assembled elements influenced by change in air and water temperature, wind velocity, tidal stream velocity and sun irradiance is taken into account. Load curtailment of the micro grid is occurred due to failure of the assembled elements and the change in renewable sources that both are addressed in the paper. For examining effectiveness of proposed approach, numerical results associated to the planning of a micro grid incorporating renewable sources considering the reliability cost are given.
Research paper
Power Electronic
N. Bagheri; B. Tousi; S.M. Alilou
Abstract
This research offers a high step-up DC-DC converter using a two- winding coupled inductor and voltage multiplier circuit (VMC) including diodes and capacitors for renewable energy (RE) usages such as photovoltaic (PV) and fuel cell (FC). The advantages of this converter are: 1) High voltage gain with ...
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This research offers a high step-up DC-DC converter using a two- winding coupled inductor and voltage multiplier circuit (VMC) including diodes and capacitors for renewable energy (RE) usages such as photovoltaic (PV) and fuel cell (FC). The advantages of this converter are: 1) High voltage gain with small duty cycle of the switch, 2) low voltage stress across switch/diodes, 3) Low number of components, 4) Lower volume and cost, 5) simple structure with only one power switch, 6) small current ripple of the input, 7) zero voltage and current (ZVS and ZCS) of the diodes, 8) improved efficiency, and 9) common grounding of the input and output. Due to the coupled inductor usage, the voltage gain is more flexible, and it can be enhanced by adjusting two different parameters: the turns ratio (N) of the coupled inductor and the duty cycle (D) of the switch. Furthermore, the voltage stresses of the semiconductors are decreased by increasing N. VMC is the other element for the power switch’s voltage stress reduction. The suggested topology could be an appropriate option for RE usage because of the small current ripple of the input and modified efficiency.
Research paper
Power System Stability
S.K. Gupta; S.K. Mallik
Abstract
Due to the exponential increase in electricity demand, the power system is being operated at its stability limit. Due to the scarcity of natural resources, the generation can not be increased. Hence, there is always a possibility of voltage collapse in the system. The voltage collapse can be predicted ...
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Due to the exponential increase in electricity demand, the power system is being operated at its stability limit. Due to the scarcity of natural resources, the generation can not be increased. Hence, there is always a possibility of voltage collapse in the system. The voltage collapse can be predicted by a number of line stability indices available in the literature. The stress level of the power system can be mitigated by integrating renewable energy resources, such as wind and solar energy. Under heavy loading conditions, the transmission lines get stressful which can be predicted by line voltage stability indices. In this paper, three line stability indices, namely, Lmn, fast voltage stability index (FVSI), and Lqp are used to identify the most stressed lines under four types of system loadings for ensuring the corrective measure to avoid this voltage instability. These indices are being evaluated using continuation power flow. The system loadability and stability are enhanced by deploying the wind energy and solar PV generation at the most appropriate location. The integrated test system includes wind and solar energy systems at one of the most severe bus, and the performance of the system is confirmed by computing the power flow (PF) using the integrated test system's line indices and the power system analysis toolbox (PSAT). The proposed approach has been validated on IEEE 14 and 118-bus test systems in MATLAB/PSAT with the deployment of wind energy and solar energy at a suitable location.
Research paper
M. Hajibeigy; V. Talavat; S. Galvani
Abstract
Due to ever-increasing energy requirements, modern distribution systems are integrated with renewable energy sources (RESs), such as wind turbines and photovoltaics. They also bring economic, environmental, and technical advantages. However, they face the network operator with decision-making challenges ...
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Due to ever-increasing energy requirements, modern distribution systems are integrated with renewable energy sources (RESs), such as wind turbines and photovoltaics. They also bring economic, environmental, and technical advantages. However, they face the network operator with decision-making challenges due to their uncertain nature. Modern distribution systems usually operate at safety margins, and any contingency may lead to power supply losses. In this regard, any attempts to increase the planner/operator's awareness of the network situation will help improve the decision quality. This paper determines the optimal locations of the RESs to enhance the expected power not served as a reliability index. Besides, it reduces power losses and minimizes the 95\% confidence interval of power losses, as much as possible for having more awareness of network states. The K-medoids data clustering method is applied to handle the uncertainties of the RESs and demand loads. The MOPSO, NSGA II, and MOGWO algorithms are used to solve the proposed problem. The efficiency of the proposed approach is tested on the IEEE standard 33-bus and 118-bus distribution networks. The obtained results show that it is possible to reach a better confidence interval while keeping the losses and reliability index at a desired level. Considering solutions with identical losses and reliability index, the confidence interval of power losses using the MOPSO algorithm is 6.86% and 39.82% better rather than the NSGA II and MOGWO algorithms in the 33-bus distribution network and it is 30.23% and 129.63% better in the 118-bus distribution network.
Research paper
Electric Mechinces & Drive
V. Naeini; N. Sadeghi
Abstract
This research paper focuses on the optimal configuration of an outer rotor permanent magnet brushless DC (ORBLDC) motor. As torque ripple is a drawback associated with this type of motor, the study proposes an optimal design to minimize torque fluctuations. The proposed design approach considers factors ...
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This research paper focuses on the optimal configuration of an outer rotor permanent magnet brushless DC (ORBLDC) motor. As torque ripple is a drawback associated with this type of motor, the study proposes an optimal design to minimize torque fluctuations. The proposed design approach considers factors such as slot width, pole arc (pole span), the number of slots, and the least common multiple factors between the number of poles and slots. Initially, the machine's parameters and dimensions are determined using design equations, and then different configurations are evaluated using the finite element method to achieve reduced torque fluctuations. The findings demonstrate that the combined design methods employed effectively minimize output torque ripples. Considering various design factors and employing advanced optimal techniques can contribute to the development of more efficient and reliable motor designs as well as reducing torque ripples.
Research paper
Distribution Systems
S.S. Halve; S.S. Raghuwanshi; D. Sonje
Abstract
Distribution systems play a crucial role in delivering power to customers and bridging the gap between bulk power transmission and end-users. Increasing energy demand due to factors like industrial development and population growth necessitates efficient distribution system management. A low X/R ratio ...
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Distribution systems play a crucial role in delivering power to customers and bridging the gap between bulk power transmission and end-users. Increasing energy demand due to factors like industrial development and population growth necessitates efficient distribution system management. A low X/R ratio in distribution networks leads to higher real power losses, lower voltage profiles, and reduced system reliability. Selecting optimal combinations of sectionalizing and tie switches for network reconfiguration is a complex and time-consuming task. This article introduces the Modified load flow (MLF) method, which combines the backward/forward sweep method with an effective approach for selecting sectionalizing and tie switches to minimize real power loss. The MLF method offers advantages such as ease of implementation, requiring fewer control parameters, and scalability to large distribution systems. The proposed MLF method is compared with particle swarm optimization (PSO) and other existing algorithms in literature such as the cuckoo search algorithm (CSA), Improved sine cosine algorithm (ISCA), and Improved harmony search algorithm (IHSA). Results obtained from MLF and PSO to IEEE-33, 69, and 118 bus radial distribution systems demonstrate significant reductions in real power loss, with MLF outperforming PSO in terms of efficiency and effectiveness. Voltage profiles at critical buses before and after network reconfiguration are examined, showing improvements in MLF better than the PSO method. Various reliability indices are evaluated to assess system performance before and after network reconfiguration, demonstrating improvements in system reliability. Overall, the proposed modified load flow method offers a promising approach to address the challenges of real power losses and system reliability in radial distribution systems.
Research paper
Planing & Reliability
A. Ghaedi; R. Sedaghati; M. Mahmoudian
Abstract
In many different nations around the world, renewable energy sources are increasingly being used to generate electricity. It is because renewable resources are sustainable, have no operating costs, and are environmentally friendly. Wind power develops quickly among renewable units, and nowadays, several ...
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In many different nations around the world, renewable energy sources are increasingly being used to generate electricity. It is because renewable resources are sustainable, have no operating costs, and are environmentally friendly. Wind power develops quickly among renewable units, and nowadays, several wind farms with large installed capacity are operating in the world. However, the erratic property of wind velocity causes generated power of wind parks to vary, which has an impact on various parts of electric network connected to wind parks and needs to be studied using new methods. In order to address reliability-based operation studies of electric network in presence of wind parks, the current research suggests a method taking into account both probabilistic and deterministic approaches for reserve scheduling. The PJM method has been modified for this reason, for incorporating wind production into the electric network. For wind farms, a several-state reliability presentation that considers hazard of assembled elements and change in produced power is developed at first stage. The appropriate amount of spinning reserve is then computed using matrix multiplication method through modified PJM methodology. Numerical simulations related to reliability test networks are provided for assessing efficacy of suggested methodology. It is concluded from numerical outcomes that the wind farms lead to the reduction of required spinning reserve. However, due to the variation of output power of wind farms arisen from variation of wind velocity, the impact of wind units in reduction of spinning reserve is less than the conventional units with the same capacity. Besides, spinning reserve calculated by well-being approach of wind farms that combines the probabilistic and deterministic indices is more accurate than the value obtained by risk indices.
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