List of Articles
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Open Access Article
1 - Low-Error and Variation-Aware Approximate Full Adders for Imprecision-Tolerant Applications
Mohammad Mirzaei سيامك محمديIn imprecision-tolerant applications such as image processing and machine learning, imprecision can be tolerated because of the nature of the application itself or the limitation of human senses. By using the approximate computation in these applications, significant po MoreIn imprecision-tolerant applications such as image processing and machine learning, imprecision can be tolerated because of the nature of the application itself or the limitation of human senses. By using the approximate computation in these applications, significant power, delay, or area reductions can be achieved. In this paper, two approximate full adders and an approximate adder, with low error are proposed. The effects of die-to-die (D2D) process variation on the threshold voltage of approximate circuits have been evaluated. For evaluating the accuracy and the variability, these approximate full adders have been used and analyzed in the ripple carry adder structure, image Sharpening and image Smoothing algorithms. In terms of power-delay-product (PDP), accuracy, and area for uniformly distributed inputs, the proposed approximate full adder 1, exhibits the best performance, and the proposed approximate full adder 2 and the proposed approximate adder, show the best peak-signal-to-noise ratio (PSNR) for real images. Manuscript profile -
Open Access Article
2 - Stochastic Planning of Resilience Enhancement for Electric Power Distribution Systems against Extreme Dust Storms
M. Haghshenas R. Hooshmand M. GholipourResilience in power systems refers to the system's ability to withstand severe disturbances with a low probability of occurrence. Because in recent years extreme dust storms have caused severe damage to Iran's electricity industry, especially in the south and southwest, MoreResilience in power systems refers to the system's ability to withstand severe disturbances with a low probability of occurrence. Because in recent years extreme dust storms have caused severe damage to Iran's electricity industry, especially in the south and southwest, in this paper proposed a new scenario-based stochastic planning model for enhancement of power distribution systems resilience against extreme dust storms. In proposed model, in the first stage, the investment costs to improve the distribution system resilience against extreme dust storms are minimized due to the financial constraints, and in the second stage, the expected operating costs in dust storm conditions are minimized due to the operating constraints. Because network's insulation equipment are major cause of distribution system vulnerabilities in the dust storms, measures in the planning stage include replacement of porcelain insulators with silicon-rubber type, installation of automatic tie switches and installation of emergency generators. In the second stage, the measures are divided into preventive actions and corrective actions, and coordination between stages 1 and 2 is implemented in such a way that the results of each stage depend on the decision variables of the other stage. The simulation results for IEEE 33-bus test system and a 209 bus radial distribution network located in Khuzestan province, Iran, confirm the efficiency of the proposed model in different financial conditions. Manuscript profile -
Open Access Article
3 - Detection and Mitigation of a Combined Cyber Attack on Automatic Generation Control
Tina Hajiabdollah H. Seifi Hamed DelkhoshRecent advances in power system monitoring and control require communication infrastructure to send and receive measurement data and control commands. These cyber-physical interactions, despite increasing efficiency and reliability, have exposed power systems to cyber a MoreRecent advances in power system monitoring and control require communication infrastructure to send and receive measurement data and control commands. These cyber-physical interactions, despite increasing efficiency and reliability, have exposed power systems to cyber attacks. The Automatic Generation Control (AGC) is one of the most important control systems in the power system, which requires communication infrastructure and has been highly regarded by cyber attackers. Since a successful attack on the AGC, not only has a direct impact on the system frequency, but can also affect the stability and economic performance of the power system. Therefore, understanding the impact of cyber attacks on AGC and developing strategies to defend against them have necessity and research importance. In most of the research in the field of attack-defense of AGC, the limitations of AGC in modeling such as governor dead band and communication network transmission delay have been ignored. On the other hand, considering two cyber attacks on the AGC and proposing a way to defend against them simultaneously, have not been considered. In this paper, while using the improved AGC model including governor dead band and communication network transmission delay, the effect of two attacks - data injection attack (FDI) and delay attack which are the most important cyber attacks on AGC - has been investigated. Also, the simultaneous effect of these two attacks is discussed as a combined cyber attack. The Kalman filter-based three-step defense method has been proposed to detect, estimate and mitigate the impact of the attacks and its effectiveness has been tested on the two-area AGC system. Manuscript profile -
Open Access Article
4 - Probabilistic Evaluation of Multi-Chamber Arresters Protection Performance for Reduction of Lighting Failures in Overhead Distribution Lines
Ramezan Ali NaghizadehA sophisticated and accurate probabilistic computational procedure for the calculation of lightning failures and evaluation of MCA performance for reduction of failures is implemented in this paper. Calculation of induced overvoltage caused by indirect lightning is impl MoreA sophisticated and accurate probabilistic computational procedure for the calculation of lightning failures and evaluation of MCA performance for reduction of failures is implemented in this paper. Calculation of induced overvoltage caused by indirect lightning is implemented based on the Agarwal method with consideration of lossy ground. The Monte Carlo method with backward scenario reduction is implemented to take into account the uncertainty of lightning flash parameters including peak current and front time with the distance of the striking point from the distribution line with applying a proper model for simulation of MCA in ATP-EMTP software. A link is developed between MATLAB and ATP-EMTP software to simulate the numerous generated scenarios and analyze the output results. Different conditions including the insulation strength of the line, the earth conductivity, and the shielding factor of the adjacent objects to the line are also taken into account in calculations. The results are presented in a proper way to make them useful for the determination of lightning-related failure rates and also accurate evaluation of the effectiveness of MCA installation in different conditions of distribution feeders. Manuscript profile -
Open Access Article
5 - Analysis of SettlingTime in Charge Pump Phase-Locked loops regarding Non-ideal Effect
hadi dehbovid habib Adarang hamidreza rabieePhase locked loops (PLL) are widely used in telecommunication systems. Frequency characteristics and settling time are the two most important features of PLLs. In phase lock loops, several nonlinear factors can be considered, one of which is the nonlinear behavior of th MorePhase locked loops (PLL) are widely used in telecommunication systems. Frequency characteristics and settling time are the two most important features of PLLs. In phase lock loops, several nonlinear factors can be considered, one of which is the nonlinear behavior of the phase detector. In fact, load pump phase locking loops (CPPLL) are nonlinear systems due to the nonlinear behavior generated by the load pump. Although the applied current is fixed in an ideal load pump, this is not fixed in practice because of the non-ideal behavior of the transistors. In this paper, considering the channel length modulation (CLM) effect caused by the drain-source voltage of MOSFET transistor, a more accurate model is presented for the phase detector. By investigating the non-linear differential equation dominating the system and using the step-response approximation for the transient time analysis, new equations are obtained for the settling time and overshooting. In order to check the validity of the specified non-linear equations, the simulation was conducted in MATLAB Simulink. Moreover, in order to better assess the proposed method, the performance of a PLL subjected to the transistor’s drain-source voltage has been simulated and the effect of the different loop parameters, such as the loop’s resistor and current has been investigated. The final results showed the appropriate accordance of the analytical equations with the simulation results. Manuscript profile -
Open Access Article
6 - A Semi-Intelligent Method for Charging Electric Vehicles in Unbalanced Four-Wire Distribution Networks
Saeed Zolfaghari MoghaddamThe growing penetration of electric vehicles (EVs) in distribution networks (DNs) has posed many challenges for electricity distribution companies, such as: increasing the amount of voltage drop, network losses and the number of outages due to the overload. To overcome MoreThe growing penetration of electric vehicles (EVs) in distribution networks (DNs) has posed many challenges for electricity distribution companies, such as: increasing the amount of voltage drop, network losses and the number of outages due to the overload. To overcome this, it is recommended to use coordinated charging methods. However, these methods require telecommunication, measurement and processing infrastructure with high costs and can only be implemented in smart grids. In this paper, a semi-intelligent method for charging EVs is presented that does not require complex infrastructure. This method, using a simple and inexpensive local automation system, charges EVs in the off-peak periods of the DN and thus improves its parameters. Since the EVs are charged at the low tariff time intervals, the proposed method will also benefit the EV owners. To achieve real results, four-wire DN is considered to model the effect of neutral conductor. To confirm the effectiveness of the proposed method, it is compared with different uncontrolled charging methods. A standard 19 bus test system is used for simulations. Manuscript profile -
Open Access Article
7 - Robust Finite-Time Chattering Free Sliding Mode Adaptive Impedance controller in Remote Control System in Presence of Random Delay
Abolfazl Kamali Ardakani Hadi SafdarkhaniRemote control of robots is one of the most relevant and practical fields in robotics. Most of the control structures of remote operation systems seek to achieve transparency and stability at the same time, which the simultaneous achievement of the both, considering the MoreRemote control of robots is one of the most relevant and practical fields in robotics. Most of the control structures of remote operation systems seek to achieve transparency and stability at the same time, which the simultaneous achievement of the both, considering the uncertainty and disturbances in the system and random delay in the communication channel is very challenging. So far, many researchers have used position, speed, force or impedance information to provide various control methods, but none of these methods have achieved complete transparency and robust stability in the presence of random delay and uncertainties and disturbances and compromises between them should be made. In this paper, using a new method, a control structure including sliding mode control, adaptive control and impedance control is presented. This method has been simulated by Simulink of MATLAB software and it has been shown that this method is able to establish ideal transparency and ensure robust stability in the system with disturbances and uncertainties in the presence of random delay in the network. Manuscript profile