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This research utilizes the innovative fractional-order Archimedean spiral moth–flame optimization (FO-AMFO) technique to address the issues of the optimal reactive power dispatch (ORPD) problem. The formulated fitness function aims to minimize power losses and determine the ideal flow of reactive power for the IEEE 30- and 57-bus test systems. The extensive functions of the fractional evolutionary computing strategy are utilized to address the minimization problem of ORPD. This involves determining the control variables, such as VAR compensators, bus voltages, and the tap setting of the transformers. The effective incorporation of reactive compensation devices into traditional power grids has greatly reduced power losses; however, it has resulted in an increase in the complexity of optimization problems. A comparison of the findings indicates that swarming fractional intelligence using FO-AMFO surpassed the state-of-the-art competitors in terms of minimizing power losses. [ABSTRACT FROM AUTHOR]

Most distribution systems are operated in an unbalanced state; hence, neutral currents can be generated by unbalanced currents in three-phase four-wire distribution systems. This paper proposes a novel adaptive reclosing scheme that uses the neutral current in a distribution system with a battery energy storage system (BESS). The BESS, which operates as an uninterruptible power supply, is connected to the load side. In the proposed scheme, there are two circuit breakers (CBs) at the source and load sides. The wavelet transform of neutral current is performed using symlets 5 mother wavelet at level 2. The summation of the absolute values of level 2 detail coefficients is calculated, and the absolute value of the differentiation of this summation is proposed as a new index for detecting fault clearance. The CB at the source side is reclosed after detecting fault clearance using ADSum. Then, the CB at the load side is reclosed after the completion of a synchronism check. To verify the proposed scheme, the BESS is modeled using the ATP-ElectroMagnetic Transients Program. In addition, various simulations are conducted according to fault types and fault clearance times. Simulation results show that successful adaptive reclosing is possible in the distribution system with the BESS. [ABSTRACT FROM AUTHOR]

This paper presents an improved directional overcurrent protection scheme using a two-stage hybrid GA-IPM algorithm. The developed approach considers the optimal time-current characteristic (TCC) selection and setting calculations of DOCRs simultaneously to protect meshed power networks. The developed formulation considers the optimal choice of the TCC curve and setting calculation simultaneously. Here, the problem is formulated as a mixed-integer nonlinear programming (MINLP) problem where a curve selection setting called curve-setting (CS) is added to the standard time multiplier-setting (TMS) and plug-setting (PS) of each relay in the DOCRs-based protection scheme. In modern relays, the selection of TCC curves is easily made from the available options. In this work, the IEC-standard curves have been considered to obtain the optimum characteristic curve selection and setting calculations. The formulated MINLP problem has been solved using the newly developed two-stage hybrid GA-IPM algorithm. In the first stage, the genetic algorithm (GA) is used to solve the problem formulated as MINLP. The obtained solution is considered the initial solution for the interior-point method (IPM) in the second state. The GA can solve the MINLP problems effectively, and IPM is superior in solving nonlinear programming problems, hence fine-tuning the results obtained by GA. The suitability and effectiveness of the proposed approach have been demonstrated on the IEEE 14 bus test system. Further, the efficacy of the developed method has been validated on an extensive IEEE 118 bus test system, and results are compared with those available in the literature. [ABSTRACT FROM AUTHOR]

In this paper, a clustering cuckoo search optimization (CCSO) is proposed. Different from the randomly generated step size in CSO, the step size in CCSO is generated by a clustering mechanism, and the value is updated according to the average fitness value difference between each cluster and the whole swarm, thereby improving the searching balance between exploration and exploitation of each solution. The effectiveness of CCSO has been validated by six typical benchmark functions and economic load dispatch problems with 6, 10, 13, 15 and 40 generators. The results of CSO and CCSO are displayed and compared in aspects of convergence rate, objective function value and robustness. Moreover, the influences of parameters as step size δ , solution number P, egg abandon fraction p a and cluster number K are all analyzed comprehensively in this study. The conclusion is that, in all the tested cases, CCSO behaves much more competitive than CSO under the same parameter setting conditions. [ABSTRACT FROM AUTHOR]

This paper proposes the novel flux barrier by using the modified Taguchi method to reduce the cogging torque. In the optimizing process the modified Taguchi method is utilized to consider multiple objective quality characteristics simultaneously such as the torque ripple and the efficiency as well as the cogging torque. The optimal novel flux barrier can effectively reduce the cogging torque and torque ripple and it is verified through the experimental results. [ABSTRACT FROM AUTHOR]

Recently, the concept of the microgrid (MG) has been developed to assist the penetration of large numbers of distributed energy resources (DERs) into distribution networks. However, the integration of DERs in the form of MGs disturbs the operating codes of traditional distribution networks. Consequently, traditional protection strategies cannot be applied to MG against short-circuit faults. This paper presents a novel intelligent protection strategy (NIPS) for MGs based on empirical wavelet transform (EWT) and long short-term memory (LSTM) networks. In the proposed NIPS, firstly, the three-phase current signals measured by protective relays are decomposed into empirical modes (EMs). Then, various statistical features are extracted from the obtained EMs. Afterwards, the extracted features along with the three-phase current measurement are input to three different LSTM network to obtain exact fault type, phase, and location information. Finally, a trip signal based on the obtained fault information is generated to disconnect the faulty portion from the rest of the MG. The significant feature of the proposed NIPS is that it does not need adaptive relaying and communication networks. Moreover, it is independent of the operating scenario and hence fault current magnitude. To evaluate the efficacy of the proposed NIPS, exhaustive simulations are performed on an international electro-technical commission (IEC) MG. The simulation results confirm the efficiency of the proposed NIPs in terms of accuracy, dependability, and security. Moreover, comparisons with existing intelligent protection schemes validate that the proposed NIPS is highly accurate, secure, and dependable. [ABSTRACT FROM AUTHOR]

The optimal allocation of protective devices is a serious issue in an electrical power system; in order to reduce the possibility of faults, the protection devices should be optimally placed. The paper presents a continuous genetic algorithm (CGA) for the optimal allocation of directional relays for the efficient energy minimization in a radial distribution system (DG). The algorithm is flexible to use for the changes and improvements in the optimal location for a DG unit and can optimize the energy consumption in the radial distribution system. The proposed algorithm has been implemented on IEEE 33 and 69-bus system using MATLAB (R2014b, MathWorks). Low energy consumption is a common design objective in an energy-constrained distribution system. Engineers, power utilities, and network operators can profit from the proposed methodology to enhance the use of DG in distribution networks. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes two controlling methods for SVC in smart grid with connected EV charger. • SMC, ASRFC with a HVC are separately applied in the grid. • This paper presents usage of proposed methods for decreasing size of capacitor and value of apparent power loss. • The proposed scheme is validated through computer simulations of a 22.9-kV grid. Abstract Electric Vehicles (EVs) play a pivotal role in reducing the emissions of greenhouse gases in the world. Currently demand for EVs has abruptly increased for transportation and other applications. Using more EVs causes an increasing load on the power system. Random EV charging yields voltage distortion, which results in an unbalanced grid. In a distributed system, the connection of EVs to the grid may diminish the power factor, which increases the apparent power loss. The Static VAR Compensator (SVC), which is a FACTS device, is applied to the power system to compensate the voltage distortions and apparent power loss. In this paper, two controlling methods are contemplated and tested in a SVC to reduce the apparent power loss and minimize the capacitor size of the SVC in comparison with the conventional control method in a SVC. Proposed methods are also compared with the conventional control method used for SVC. The Slide Mode Controller (SMC) and Asymmetric Synchronous Reference Frame Controller (ASRFC) with a Harmonic Voltage Compensator (HVC) are separately applied in the grid. This paper presents usage of SMC and ASRFC methods for decreasing size of capacitor and value of apparent power loss through computer simulations of a 22.9-kV grid. With application of new controllers, apparent power loss of grid will be reduced as compared with conventional method of SVC controller. Moreover, the size of SVC capacitor can also be reduced. [ABSTRACT FROM AUTHOR]

A fully coupled finite element analysis (FEA) technique was proposed for solving the ion-flow field due to corona discharge under a high-voltage direct-current (HVDC) bipolar transmission line employing a field enhancement factor. To cover the shape and roughness effects for the stranded wire conductor, the field enhancement factor was introduced in the charge generation mechanism. The employed fully coupled FEA can solve the corona electric field with space charge propagation without the Deutsch assumption and is stable and fully convergent regardless of the possible higher values of wind speed. First, we simulated a dc ±500 kV transmission line tower consisting of six subconductor bundles in a bipolar configuration. Furthermore, the accuracy and the reliability of the simulated results were validated using the experimental results from the literature for a dc ±800 kV one-bipolar transmission line with six subconductor bundles. Moreover, the electric fields were assessed with and without consideration of the space charge, including the wind effect. Overall, the simulated results agree with the experimental results from the literature. [ABSTRACT FROM AUTHOR]

This paper proposes an optimized rotor pole shape that can effectively reduce the partial demagnetization effect and cogging torque. First, for reducing the peak amplitude of the external field that directly affects the partial demagnetization on the permanent magnets in spoke-type permanent magnet motor, we conduct a variation of core shape and insertion of a barrier. Second, with the rotor shape obtained by the first processes for reducing the partial demagnetization effect, another part of the rotor pole is varied to make better sinusoidal distributed air gap flux density to reduce the cogging torque. In the process of designing the rotor pole shape, a steepest descent method and a response surface method are applied for improving convergence. By using the finite element method, we show that the optimized rotor pole shape drastically reduces the effect of the partial demagnetization and cogging torque. [ABSTRACT FROM AUTHOR]

This article proposes an adaptive operating scheme for a recloser based on classified detection of transient faults and permanent faults in a distribution system. Wavelet transform is used to classify whether a fault is transient or permanent in nature. The Haar mother wavelet of the current flowing in a neutral line has more rich harmonics than other mother wavelets, such as Daubechies, Symlets, Coiflets, and Biorthogonal, so the total harmonic distortion of the Haar mother wavelet is applied for estimating the instant of fault clearance and giving a signal for operating action to the recloser (reclosing). The various simulations according to the fault clearance time and fault type are performed using the Electromagnetic Transient Program to verify the proposed algorithm. The simulation results show the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

With the needs of developing technology, we aim to provide an open forum on this research idea, specifically in smart devices and their application, and related algorithms/applications. Recently, AI-oriented research has been provided with its fundamental research on application to networked systems [[4]] and the heuristic and metaheuristic algorithms also obtained much attention based on nature-inspired optimization algorithms [[5]]. From the Special Issue, we can see that the topics range from smart device development and applications to processing algorithm development and applications as well. [Extracted from the article]

We suggested that the neutral line is a more effective location for a superconducting fault current limiter (SFCL) in a three-phase power system. To confirm it, we analyzed the quench and recovery characteristics of SFCL applied into the neutral line in cases of non-symmetrical ground faults, such as single line-to-ground and double line-to-ground faults. Through a comparative analysis based on the experimental results for two SFCLs applied either to the neutral line or to the three-phase power line, it was confirmed that the SFCL applied into the neutral line of the power system was more advantageous from the viewpoint of both the practical use of the SFCL and the SFCL's coordination with other related protective devices in the power system. [ABSTRACT FROM AUTHOR]

In recent years, perovskite solar cells (PSCs), often referred to as the third generation, have rapidly proliferated. Their most prominent deficiencies are their low efficiency and poor stability. To enhance their productivity, a combination of silicon and perovskite is employed. Here, we present a 3D simulation analysis of various electrical and optical properties of PSCs using the SILVACO simulation software. Using the inverted planar method with inorganic transport materials and the proper selection of anti-reflective coatings with a back contact layer increases the efficiency of PSCs to 28.064%, and enhances their stability without using silicone composites. Several materials, including CaF2, SiO2, and Al2O3, with various thicknesses have been employed to investigate the effect of anti-reflective coatings, and to improve the efficiency of the simulated PSC. The best thickness of the absorbent layer is 500 nm, using a CaF2 anti-reflective coating with an optimal thickness of 110 nm. A polymer composition of Spiro-OMeTAD and inorganic materials Cu2O and NiOx was used as the hole transport material (HTM) and inorganic ZnO was employed as the electron transport material (ETM) to optimize the solar cell efficiency, and an optimized thickness was considered for these materials. Yields of 29.261, 28.064 and 27.325% were obtained for Spiro-OMeTAD/ZnO, Cu2O/ZnO and NiOx/ZnO, respectively. Thus, Spiro-OMeTAD yields the highest efficiency. This material is highly expensive with a complex synthesis and high degradability. We proposed to employ Cu2O to alleviate these problems; however, this reduces the efficiency by 1.197%. As a graphene connector has high flexibility, reduces cell weight, and is cheaper and more accessible compared to other metals, it was regarded as an optimal alternative. The simulation results indicate that using the inverted planar method with inorganic transport materials for graphene-based PSCs is highly promising. [ABSTRACT FROM AUTHOR]

The relay coordination problem is of dire importance as it is critical to isolate the faulty portion in a timely way and thus ensure electrical network security and reliability. Meanwhile a relay protection optimization problem is highly constraint and complicated problem to be addressed. To fulfill this purpose, Harris Hawk Optimization (HHO) is adapted to solve the optimization problem for Directional Over-current Relays (DOCRs) and numerical relays. As it is inspired by the intelligent and collegial chasing and preying behavior of hawks for capturing the prey, it shows quite an impressive result for finding the global optimum values. Two decision variables; Time Dial Settings (TDS) and Plug Settings (PS) are chosen as the decision variables for minimization of overall operating time of relays. The proposed algorithm is implemented on three IEEE test systems. In comparison to other state-of-the-art nature inspired and traditional algorithms, the results demonstrate the superiority of HHO. [ABSTRACT FROM AUTHOR]

This paper proposes a novel high voltage conversion gain DC/DC boost converter for renewable energy applications and systems. The proposed converter utilizes a three-winding coupled inductor. The presented converter benefits from a unique advantage, as the actual turn ratio of the coupled inductor is decreased in the charging state of the coupled inductor. However, while the inductor is discharging, the actual turn ratio is increased. This feature leads to a very high voltage conversion gain. Furthermore, a passive clamp circuit is employed to recover the leakage current of the coupled inductor. The voltage stresses on the semiconductors are also reduced. In addition, the average current of the primary side of the coupled inductor is zero. This will reduce the total energy stored in the passive elements of the converter. The paper analyzes the Continuous Conduction Mode (CCM) and the operation principles of the presented converter are thoroughly derived. A 250 W laboratory hardware prototype is prepared to verify the proper operation of the presented converter. The obtained experimental results validate the feasibility of the presented converter. [ABSTRACT FROM AUTHOR]

In power systems protection, the optimal coordination of directional overcurrent relays (DOCRs) is of paramount importance. The coordination of DOCRs in a multi-loop power system is formulated as an optimization problem. The main objective of this paper is to develop the whale optimization algorithm (WOA) for the optimal coordination of DOCRs and minimize the sum of the operating times of all primary relays. The WOA is inspired by the bubble-net hunting strategy of humpback whales which leads toward global minima. The proposed algorithm has been applied to six IEEE test systems including the IEEE three-bus, eight-bus, nine-bus, 14-bus, 15-bus, and 30-bus test systems. Furthermore, the results obtained using the proposed WOA are compared with those obtained by other up-to-date algorithms. The obtained results show the effectiveness of the proposed WOA to minimize the relay operating time for the optimal coordination of DOCRs. [ABSTRACT FROM AUTHOR]

High voltage direct current (HVDC) transmission is being widely implemented for long-distance electrical power transmission due to its specific benefits over high voltage alternating current (HVAC) transmission. Most transmission lines pass through forests. Around the HVDC lines, an arc to a nearby tree may be produced. Thus, there should be a minimum possible clearance distance between a live conductor and a nearby tree, named the minimum vegetation clearance distance (MVCD), to avoid short-circuiting. Measurement of minimum clearance distance between the conductor and trees is a significant challenge for a transmission system. In the case of HVAC transmission, a large amount of research has been undertaken in the form of the Gallet equation for the measurement of this distance, whereas for HVDC transmission no substantial work has been done. An equivalent AC voltage value can be derived from the DC voltage value in order to use the Gallet equation. This paper presents an experimental measurement technique for determining the MVCD at 500 kV to verify the results obtained from the Gallet equation in the case of DC voltage. Performing the experiment with a 500 kV DC line is not possible in the laboratory due to safety concerns. Therefore, an experiment up to 60 kV is conducted to measure the MVCD for DC voltage. The measured results achieved from the experiment are then extrapolated to calculate the MVCD at 500 kV. [ABSTRACT FROM AUTHOR]

The economic load dispatch (ELD) problem is an optimization problem of minimizing the total fuel cost of generators while satisfying power balance constraints, operating capacity limits, ramp-rate limits and prohibited operating zones. In this paper, a novel multi-population based chaotic JAYA algorithm (MP-CJAYA) is proposed to solve the ELD problem by applying the multi-population method (MP) and chaotic optimization algorithm (COA) on the original JAYA algorithm to guarantee the best solution of the problem. MP-CJAYA is a modified version where the total population is divided into a certain number of sub-populations to control the exploration and exploitation rates, at the same time a chaos perturbation is implemented on each sub-population during every iteration to keep on searching for the global optima. The proposed MP-CJAYA has been adopted to ELD cases and the results obtained have been compared with other well-known algorithms reported in the literature. The comparisons have indicated that MP-CJAYA outperforms all the other algorithms, achieving the best performance in all the cases, which indicates that MP-CJAYA is a promising alternative approach for solving ELD problems. [ABSTRACT FROM AUTHOR]

In an electrical power system, the coordination of the overcurrent relays plays an important role in protecting the electrical system by providing primary as well as backup protection. To reduce power outages, the coordination between these relays should be kept at the optimum value to minimize the total operating time and ensure that the least damage occurs under fault conditions. It is also imperative to ensure that the relay setting does not create an unintentional operation and consecutive sympathy trips. In a power system protection coordination problem, the objective function to be optimized is the sum of the total operating time of all main relays. In this paper, the coordination of overcurrent relays in a ring fed distribution system is formulated as an optimization problem. Coordination is performed using proposed continuous particle swarm optimization. In order to enhance and improve the quality of this solution a local search algorithm (LSA) is implanted into the original particle swarm algorithm (PSO) and, in addition to the constraints, these are amalgamated into the fitness function via the penalty method. The results achieved from the continuous particle swarm optimization algorithm (CPSO) are compared with other evolutionary optimization algorithms (EA) and this comparison showed that the proposed scheme is competent in dealing with the relevant problems. From further analyzing the obtained results, it was found that the continuous particle swarm approach provides the most globally optimum solution. [ABSTRACT FROM AUTHOR]