Power
Zahra Gholami; Rahim Ildarabadi; Hamed Heydari-doostabad
Abstract
This paper discusses the application of the principle of duality to conventional voltage-based DC-DC converters, such as buck, boost, fly-back, cuk, sepic, and zeta topologies, in order to obtain their current-based DC-DC converters. The duality approach involves finding the dual of a circuit, which ...
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This paper discusses the application of the principle of duality to conventional voltage-based DC-DC converters, such as buck, boost, fly-back, cuk, sepic, and zeta topologies, in order to obtain their current-based DC-DC converters. The duality approach involves finding the dual of a circuit, which is a circuit equivalent to the original circuit but with certain parameters swapped. Therefore, this paper presents a comprehensive study on achieving the most commonly used topologies of DC-DC current converters by applying the duality approach to their DC-DC voltage converters. This approach serves as a solution for applications where a current source is available and there is a need for output current control. An application of these current converters is to power current-based loads, such as light-emitting diodes (LEDs), and to provide conversion for current sources, such as photovoltaics (PV). As an advantage, these converters do not require additional inductors at their input or output terminals. Additionally, the paper provides a detailed explanation of the principle of operation and mathematical analysis of the conversion ratio for the discussed current converters. The proposed current converters and their application as an interface between a PV and a high-power LED were simulated using MATLAB to verify the mathematical equations. Overall, this paper provides a useful study guideline for understanding the principle of duality and the application of DC-DC current converters for current-based loads and sources.
Power
Arash Moghadami; Davood Azizian; Amin Karimi
Abstract
The healthy operation of high-power transformers plays a crucial role in the reliability of power systems. Given the thermal model of transformers under heavy-load and high-temperature conditions, the hot spot temperature exceeding the maximum allowable value may result in oil dissolution and cascading. ...
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The healthy operation of high-power transformers plays a crucial role in the reliability of power systems. Given the thermal model of transformers under heavy-load and high-temperature conditions, the hot spot temperature exceeding the maximum allowable value may result in oil dissolution and cascading. This paper uses a thermal model of transformers to analyze the hot spot temperature load level under predicted ambient temperature, which may cross the healthy conditions. Then, an Incentive-Based Demand Response (IBDR) and a thermal model of transformers are used to determine optimal load curtailment. On the other hand, as the paper uses the demand response (DR) for security reasons, the risk of load participation in IBDR programs should be minimized. Hence, a Response Fatigue Index (RFI) is employed to maintain the comfort level of demands participated in DR. Also, the feasible solution area for multi-objective optimization is determined, given costs and RFI, using the sequential solution of a single-objective problem with cost reduction as the objective and RFI as the constraint with different levels of maximum acceptable RFI. The developed model was applied to a real substation in Iran as a test case. The results show that DR can enhance the reliability and life expectancy of the transformer while keeping the comfort level of loads as high as possible.
Power
Hamid Reza Safa; Ali Asghar Ghadimi; Mohammad Reza Miveh
Abstract
Renewable energy sources are particularly important in clean energy transitions and must be considered in Generation Expansion Planning (GEP) problems due to low cost, ease of installation, and ability to implement Demand Response (DR) programs. However, challenges such as the stochastic nature of renewable ...
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Renewable energy sources are particularly important in clean energy transitions and must be considered in Generation Expansion Planning (GEP) problems due to low cost, ease of installation, and ability to implement Demand Response (DR) programs. However, challenges such as the stochastic nature of renewable energy sources, consumer unawareness regarding participation in DR programs, and difficulties in integrating some resources have posed challenges to the use of these resources in the GEP problem. This paper addresses these challenges by using the Weibull distribution function to model wind power plants' uncertainty and rewards and penalties to motivate consumer participation in the GEP problem. To achieve these objectives, initially, the adequacy assessment of the generation system is performed analytically using the reliability index, which includes Expected Energy Not Supplied (EENS), considering the forced outage rate of generators in the DIgSILENT power factory through Python programming. Subsequently, an optimized GEP model is presented to enhance the generation system's adequacy against short-term demand for the next year. In this model, wind farms along with the DR program are integrated and optimized using the genetic algorithm, employing Python programming. The genetic algorithm selects the number of existing turbines in the wind power plant and the level of consumer participation needed to reduce the EENS to the desired value at the minimum cost. Validation of the proposed model is conducted on a 9-bus network. The strength of the presented method lies in its applicability to real-world networks modeled in the DIgSILENT power factory.
Power
Amir Ghaedi; Mehrdad Mahmoudian
Abstract
In recent years, energy storage systems are increasingly used in power systems to store electricity when the generated power is more than the required load. The advantages of the energy storage systems in the power system include improved reliability, energy storage in non-peak times and production in ...
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In recent years, energy storage systems are increasingly used in power systems to store electricity when the generated power is more than the required load. The advantages of the energy storage systems in the power system include improved reliability, energy storage in non-peak times and production in peak times that results in the peak reduction of the power system, storage at times of low electricity prices, and generate at times of high electricity prices, and storage of the surplus production capacity of renewable energy resources such as wind turbines and photovoltaic systems that their production is not controllable. Among different energy storage systems, pumped-storage generation units can be integrated into electricity networks with high-energy storage capacity and no environmental effects. For this purpose, in this research, the adequacy assessment of power systems including pumped-storage generation units is studied. At first, the paper develops a reliability model for these energy storage systems considering the failure of composed components including the motor-generator, pump-turbine, control, protection and measurement systems, turbine housing, water channel, up and down reservoir and transformer. To consider effect of pumped-storage generation plants on the reliability of the power system, the load duration curve of system is modified. Then, the proposed model is implemented for assessing the adequacy of power systems considering the effect of generation and transmission networks using an analytical method through contingency analysis technique. To study the effectiveness of suggested reliability model, numerical results related to reliability assessment of RBTS and IEEE-RTS are presented. It is concluded from numerical outcomes that pumped storage power plants can improve the reliability indices of the power systems. Integration of understudied pumped storage generation unit into RBTS, system load can increase up to 15 MW.
Power
Babak Keshavarz Zahed; Mohammad Hassan Moradi
Abstract
The penetration of double-fed induction generators (DFIG) as renewable energy sources (RES) in power systems leads to fluctuations caused by wind energy. Therefore, based on this challenge, a wide area damping controller (WADC) has been designed to compensate the oscillatory modes by a static synchronous ...
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The penetration of double-fed induction generators (DFIG) as renewable energy sources (RES) in power systems leads to fluctuations caused by wind energy. Therefore, based on this challenge, a wide area damping controller (WADC) has been designed to compensate the oscillatory modes by a static synchronous series compensator (SSSC). In addition to the design of WADC for SSSC, a parallel compensator in the form of a supercapacitor energy storage system (SCESS) has been used in the DC link of the wind unit so that DFIG can be used optimally to supply the power system. The design method for compensating time delays in WADC is based on free weight matrices (FWM). First, based on the theory of robust control based on delay-dependent feedback, a set of constraints related to linear matrix inequality (LMI) are formulated. In the following, the free weight matrix (FWM) has been used to solve the delay-dependent time problem. The purpose of applying FWM is to extract the most optimal gain for the controller in the presence of time delay. The proposed FWM matrix tries to find the most optimal gain in the controller with the help of an iterative algorithm based on the linearization of conical complement. The simulation results have been implemented in the MATLAB software environment after obtaining the critical modes in the nonlinear time domain on the power system of 16 improved machines. Based on the simulation results, the robustness of the proposed controller under various uncertainties is clearly shown in this paper.
Telecommunications
Patikiri Arachchige Don Shehan Nilmantha Wijesekara
Abstract
Network Virtualization (NV) techniques enable high scalability and isolation by abstracting physical resources to provide a logical network representation that can coexist with a physical networking framework. Traditional NV is prone to security attacks and has lower privacy and trustfulness compared ...
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Network Virtualization (NV) techniques enable high scalability and isolation by abstracting physical resources to provide a logical network representation that can coexist with a physical networking framework. Traditional NV is prone to security attacks and has lower privacy and trustfulness compared to blockchain-established NV. We diagnose the BC-established NV construct under 5 segments and closely appraise the literature in reference to NV technique, virtualization technology, BC-related properties, and network properties. We racked up a starting sample of 85 sources by filtering literary work for qualifying conditions searched from article retrieval platforms, engaging a rigorous and prolonged approach. Anchored from this research, in BC-established NV, we demonstrate that BC can act as a broker/manager for NV, act as a secure storage by preventing double-spending attacks, provide secure virtual network embedding with high fault tolerance, engage BC and smart contacts for resource trading in the process of NV, engage dedicated consensus approaches to reach agreement for NV among multiple parties for reducing security attacks, and establish BC-established access control for NV. Complete interpretation disseminates that from interpreted BC-established NV schemes, 45% engage BC and smart contracts for agreements and resource trading for NV, 95% engage regular BC architecture, Proof-of-Work (PoW) and Practical Byzantine Fault Tolerance (PBFT) being the most frequently used consensus, 80% engage the overlay network concept, and it has been engaged abundantly (27.5%) in 5G networks. Finally, we deliberate the possibilities and obstacles of the framework of blockchain-established NV and then provide suggestions to suppress them.
Power
Iman Ali Hassanvand; Javad Ebrahimi; Mahyar Abasi
Abstract
The dominant measures taken in distribution networks to solve the problem of voltage instability include feeder reconfiguration techniques, allocation of capacitor banks, use of tap changers, etc. However, these traditional methods suffer from numerous problems. Many studies have been carried out to ...
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The dominant measures taken in distribution networks to solve the problem of voltage instability include feeder reconfiguration techniques, allocation of capacitor banks, use of tap changers, etc. However, these traditional methods suffer from numerous problems. Many studies have been carried out to solve these problems in recent years. Compared with traditional methods, reactive power control (RPC) of photovoltaic (PV) inverters does not require additional investment, and given that PV inverters often function at a capacity below their rated value, the excess capacity can be utilized to assist in supplying reactive power to the grid. However, achieving voltage regulation in imbalanced distribution networks via RPC is a complex issue. Hence, the primary objective of this work is to utilize the reactive power capacity of photovoltaic inverters to achieve decentralized regulation of effective voltage of the network using a consensus algorithm and PID controller in two stages.
Power
Mohammad Abedini; Mahyar Abasi
Abstract
Maintaining power system stability can be challenging due to low-frequency fluctuations. Traditionally, power system stabilizers (PSS) and unified power flow controllers (UPFC) have been used to address this issue. This paper proposes a novel approach that leverages both PSS and UPFC simultaneously, ...
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Maintaining power system stability can be challenging due to low-frequency fluctuations. Traditionally, power system stabilizers (PSS) and unified power flow controllers (UPFC) have been used to address this issue. This paper proposes a novel approach that leverages both PSS and UPFC simultaneously, controlled by an optimized fuzzy logic system. The proposed fuzzy controller aims to enhance the efficiency of both PSS and UPFC, ultimately boosting system damping. The controller takes two key inputs: changes in angular speed and power angle. To dynamically adjust its response to changing system conditions, a shuffled frog leaping algorithm optimizes the fuzzy controller's gains. To assess the effectiveness of the controller, simulations are conducted across three different loading levels for the studied system. The results are presented for each stage and demonstrate a significant reduction in overshoot and improved overall system damping. Our method achieves a remarkable 43% enhancement in damping compared to PSS, a 45% improvement over UPFC alone, and a staggering 48% advantage over the hybrid PSS-UPFC approach.
Power
Musa Khosravi; Saeed Hasanvand; Mahyar Abasi; Mohammad Esmaeil Hassanzadeh
Abstract
Considering the challenges of using fossil fuels including price and pollution and the increasing development of electric vehicles, the energy supply from other sources should be considered. One of the main challenges of electric vehicles is their impact on the distribution network, especially the time ...
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Considering the challenges of using fossil fuels including price and pollution and the increasing development of electric vehicles, the energy supply from other sources should be considered. One of the main challenges of electric vehicles is their impact on the distribution network, especially the time of charging and its coincidence with the peak load of the network, which causes an increase in power consumption, double pressure on the network, and more and faster depreciation of distribution network equipment. Also, producing more energy during peak times leads to increased costs and air pollution. In this paper, the use of renewable energy to charge electric vehicles is investigated in such a way that the consumers of electric vehicles use solar panels and batteries to store solar energy so that it can be used for charging during peak times. The costs of installing solar panels, the consumption of electric vehicles, the amount of energy generation, as well as the emission of fossil fuel pollutants that fossil power plants produce at peak times have been investigated. Furthermore, a comparison has been made between the use of renewable and non-renewable energy. Consequently, the proposed method is about 112494 dollars more economical than the system without renewable energy. It is also suggested to consider incentives from the government for the consumer to reduce the capital and operating cost of the photovoltaic system to diminish the investment return time.
Power
Arash Rohani; Javad Ebrahimi; Shirin Besati
Abstract
A two-layer combined control method is developed for a four-leg Distribution Static Synchronous Compensator (DSTATCOM). The method aims at harmonics reduction, demand-generation equilibrium, power factor modification, voltage adjustment, and neutral current modification in a 3ph 4-wire distribution system. ...
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A two-layer combined control method is developed for a four-leg Distribution Static Synchronous Compensator (DSTATCOM). The method aims at harmonics reduction, demand-generation equilibrium, power factor modification, voltage adjustment, and neutral current modification in a 3ph 4-wire distribution system. In the first layer, a recursive Least Error Square algorithm (RLES) based on a new fuzzy logic-based variable forgetting factor is used for Real-time estimation of voltage and current signals and their constituting components. The second layer’s duty is to extract the reference currents using the outputs of the first layer. Besides the high accuracy and convergence speed, the suggested algorithm is independent of coordinate transformations and complex computation when attempting to derive the reference currents of DSTATCOM. To enhance the dynamic performance of DSATATCOM, an adaptive hysteresis band current controller was utilized to generate switching signals. The effectiveness of the presented control strategy was verified via simulation studies implemented in MATLAB/Simulink environment.
Control
Behnam Ersi Alambaz; Mohsen Ghalehnoie; Hamid Reza Moazami
Abstract
This paper explores the impact of two types of experiments, known as "long pulse" and "short pulse," experiments, on identifying models for Lithium-ion batteries. The focus is on improving the estimation of the state of charge (SoC) using an extended Kalman filter. The results consistently demonstrate ...
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This paper explores the impact of two types of experiments, known as "long pulse" and "short pulse," experiments, on identifying models for Lithium-ion batteries. The focus is on improving the estimation of the state of charge (SoC) using an extended Kalman filter. The results consistently demonstrate that applying the extended Kalman filter to models identified through long pulse experiments outperforms those identified through short pulse experiments in estimating battery SoC and terminal voltage. The article delves into the reasons for this improvement from both circuit and electrochemical perspectives, providing insights into the obtained results. Thus, the study advocates for the preference of long pulse strategies to enhance the performance of Lithium-ion batteries, offering insights that contribute to the development of innovative and sustainable energy storage solutions.
Electronics
Pegah Paknazar; Maryam Shakiba; Gholamreza Shaloo
Abstract
In this study, the effect of the width of the n- and p-strips and gap between the electrodes on output characteristics of the IBC-SHJ solar cell including short-current current density, open-circuit voltage, fill factor and efficiency was investigated using Silvaco ATHENA and ATLAS simulation software. ...
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In this study, the effect of the width of the n- and p-strips and gap between the electrodes on output characteristics of the IBC-SHJ solar cell including short-current current density, open-circuit voltage, fill factor and efficiency was investigated using Silvaco ATHENA and ATLAS simulation software. In this regard, the efficiency of the IBC-SHJ solar cell was improved by developing the geometry of the back contacts. The values for the short-circuit current density, open-circuit voltage, fill factor and efficiency of the solar cell were analysed using physical phenomena and the distribution of the electric field and electric potential for the aforementioned parameters. The results have shown that the width of the n- and p-strips is one of the most effective parameters for improving the efficiency improvement. Moreover, a maximum efficiency of 23.52% was achieved for IBC-SHJ with improved solar cell parameters, focusing on the elimination of additional ARCs and greater structural periodicity. Thus, a simple structure with no complexity in the fabrication process is proposed. The results show that the best width of the p-strip, n-strip and gap between the electrodes is 400 μm, 80 μm and 30 μm, respectively, to achieve improved efficiency.