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The integration of vast quantities of clean energy causes intense impact on the power grid reliability. Digital Twin can be used to handle the high‐growth data flow generated in the power grid, and thus accelerate its digitalization process to fulfill the clean energy consumption target. As the traditional central cloud network structure can no longer effectively support the operation of digital twin power grid, the mobile edge network can be used as a reasonable substitute. To support the information interaction process of the mobile edge network, considering total profit, time delay and energy consumption, this paper proposes the mobile edge network communication and computing resource joint allocation model. On the basis, the GA‐PSO algorithm is proposed to solve the resource allocation optimization function. The feasibility and effectiveness of the proposed model is verified by the related simulation experiment. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Pedestrians are essential component in traffic, and with the advent of intelligent transportation systems, conflicts over right‐of‐way between pedestrians and other traffic participants have become prevalent. Predicting pedestrian intentions and motions is crucial for autonomous driving and intelligent transportation. However, pedestrian prediction faces challenges such as the variability of pedestrian intentions and the flexibility of their motions, as well as the need for highly generalization capability and lightweight modeling on autonomous vehicles with limited computing power. To face these challenge, this paper proposes a Social Artificial Potential Field (Social‐APF) method for pedestrian trajectory prediction. The method combines target intention feature and surrounding obstacles features. We test the performance of Social‐APF on several public datasets. The results demonstrate that the Social‐APF method outperforms state‐of‐the‐art approaches on the public datasets in both lightweight and model accuracy. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Off‐line partial discharge (PD) diagnosis, which requires an additional power supply has been accepted as an essential step in ensuring the integrity of power cable systems during commissioning testing. Many types of energizing voltage sources (e.g., alternating current resonance, damped alternating current, very low frequency [VLF] sine, and VLF‐cosine rectangular) have been developed, which are used in practice. However, choosing the optimal energizing voltage waveforms for PD testing is still controversial because their capability to motivate PD activities is still unclear. Accordingly, this paper compares the PD ignition capacity of the aforementioned power sources on six well‐designed PD defects in real cable joints. The influence of test voltage frequencies and waveforms are verified. The results show that the PD inception voltage and PD magnitudes in the cable joint defects do not change significantly as a function of the sinusoidal voltage frequency and the VLF‐cosine rectangular voltage exhibits excellent PD ignition capability with a low PD inception voltage and large PD magnitude. Moreover, the dynamic behavior of space charge in a PD defect caused by a gap is analyzed in order to explain the obtained results. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The vegetable‐insulating oils are used in electrical systems recently. Most of vegetable‐insulating oils are manufactured from new oils. In this paper, we propose to develop the insulating oils from the used cooking oil. The used cooking oils that means thermal degraded—vegetable oil has high kinematic viscosity that does not meet the JIS values. In this study, the kinematic viscosity of thermal degraded oil was decreased using ester exchange reaction. We simulated the thermally‐degraded rice ester oil as used cooking oil, and investigated the potential of used cooking oil as insulating oil. We manufactured rice ester oil after thermal degradation before and after the ester‐exchange reaction and measure kinematic viscosity, AC breakdown voltage, moisture amount and volume resistivity for oil samples. We evaluated the degree of thermal degradation of the sample oil using total polar molecule (TPM). The results are described as follows. (1) The kinematic viscosity and volume resistivity of the rice oil increased with the thermal degradation progress (increase in TPM). The kinematic viscosity of the rice ester oil at each TPM value decreased after the ester‐exchange reaction. (2) After vacuum deaeration (2 h at 80°C and 22 h at room temperature), the moisture content of the rice oil before and after the ester‐exchange reaction was almost the same. (3) The AC breakdown strength after ester‐exchange reaction was higher than that of the untreated oil. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Obstructive sleep apnea (OSA) is a common sleep disorder, and polysomnography (PSG) is the gold standard for diagnosing OSA. However, patients often have to wait long before receiving the costly PSG test in a hospital. Hence, low‐cost and easy‐to‐use portable screening tools were developed for predicting OSA. Based on our recent study, this paper presents a feature extraction method with multiple receptive fields applied to the input electrocardiography (ECG) signals of a model to improve its performance in OSA severity classification. This work also employs unsegmented ECG signals as input to keep all the advantages from our original approach. The proposed model achieves an overall accuracy of 59.49% for four‐level OSA severity classification, giving an improvement of approximately 2% compared to our original work. The effectiveness of the proposed method is demonstrated. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Mechanical characterization of cells is important for understanding their behavior. This paper reports on an in situ evaluation of the stiffness of cellular spheroids using a pinching device. The pinching device is integrated with a bimorph piezoactuator and strain gauge. It can pinch an object by combining a piezo bimorph actuator and a thin Si structure and can detect the reaction force from an elastic object using a strain gauge integrated into the thin Si structure. The strain gauge can detect the bending deformation of the device and estimate the reaction force by considering actuation. This paper presents the design of the pinching device and experimental results when used for the in situ evaluation of the stiffness of cellular spheroids. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper presents an evolutional topology optimization of electric machines, which works like gradient‐based local search methods, based on the covariance matrix adaptation evolution strategy (CMA‐ES). The present method enables to improve the performance of initial machine shapes without computing the deviation of the objectives. Moreover, for the resultant shapes obtained by the present topology optimization method, this paper also presents a sensitivity analysis method based on the normal distribution which is used to seek for solutions in CMA‐ES. Using the present sensitivity analysis method, important parts which contribute to improve a machine characteristic can be visualized. The two present methods are applied to the optimization problem of a synchronous reluctance motor. It is shown that initial rotor shapes defined by designers can effectively be modified using the present optimization method. Moreover, it is also shown that the sensitivity distributions with respect to some machine characteristics are visualized by the present method. In addition, each machine characteristic is respectively improved by modifying the machine shape according to the respective sensitivities. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In recent years, the object‐tracking algorithm based on Siamese network has gradually become the mainstream algorithm in the field of object tracking due to its characteristics of balancing speed and accuracy. The majority of Siamese‐based trackers only use the first frame extraction template for subsequent tracking in order to prevent the introduction of noise. However, merely with a single initial template employed, it is difficult to achieve the best performance of the tracker in the face of complex tracking environments such as occlusion, motion blur, and non‐rigid deformation. Therefore, the present paper proposes a new multi‐template fusion module based on graph attention network (G‐M module), which consists of two parts: a graph‐attention‐network‐based feature‐embedding module (G module) and a multi‐template fusion module (M module). It can greatly reduce the background noise introduced by template updating while improving the tracker's ability to adapt to changes in object appearance. In addition, in order to maximize the value of G‐M module, the present paper also puts forward a two‐stage template update threshold judgment mechanism. The Pearson correlation coefficient (PCCs) is introduced and combined with APCE and the maximum response value (F‐max) to filter out reliable templates for updating. In this paper, the proposed method is applied to the SiamFC and SiamFC++ trackers. Extensive experiments on mainstream data sets, such as OTB2015, VOT2016, and GOT‐10 k, show that the proposed method can effectively update the tracking template and improve the tracker performance. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The high‐temperature electric‐actuated valve widely adopts the split structure, and the valve stem drives the opening and closing of the valve after passing through the high‐temperature packing and sealing structure. However, the transmission chain is too long, which cannot meet the pursuit of small volume and lightweight in the nuclear industry. In this paper, a novel integrated structure of high‐temperature direct drive electric‐actuated valve canned permanent magnet synchronous motor (DDEAV‐CPMSM) is proposed. The structure omits the dynamic sealing structure composed of stuffing box, pressure plate and pressure sleeve, as well as the transmission structure of gears and couplings, and the reliability is significantly improved. This paper focuses on the calculation of the dimension parameters, thermal load design, and electromagnetic vibration of DDEAV‐CPMSM, and compares it with the integrated structure of the induction motor to explore the optimal topology of the high‐temperature electric‐actuated valve. Aiming at the problem of serious heat generation in limited space, it is difficult to simulate the running time of high‐temperature valve. Based on the magneto‐thermal coupling method, a 3D temperature field model considering high‐temperature heat source, canned sleeve eddy current loss, and hydraulic friction loss is established. The steady‐state temperature distribution of the system at high temperature and the transient temperature change law of valve opening and closing are analyzed, and the minimum time of secondary start‐up and the maximum running time under fault conditions are further studied, to provide a theoretical basis for the application of DDEAV‐CPMSM. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

With increasing attention to the secondary use of data, privacy protection laws such as the General Data Protection Regulation (GDPR) and California Consumer Privacy Act (CCPA) have come into force to protect residents from unauthorized exploitation of personal data. Flow management is an effective method to track the distribution of user data in a multi‐domain network environment. Transparency in the relationship between data and service providers is essential to track the status of data provision. Vendor and Consumer Relationship Management (VCRM) manages this relationship by regulating relevant flow information. VCRM is expected to collaborate with the edge‐computing environment in the management of regional unit flow, wherein all access to personal user data should be restricted in accordance with the stakeholders' requests. Accordingly, this study proposes a packet processing function that collaborates with VCRM to manage the access control of flows passing through a regional network. Moreover, this paper proposes methods to reduce packet processing time on the switch, and requests to the switch controller. Using tag‐based matching and cache injection methods, the number of requests to the controller decreased to 33.4% of the original figure. Our proposed method also reduces the total processing time on flow management switches in the network environment in the analysis of encrypted TCP streams such as HTTP over TLS and MQTT over TLS. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In order to improve the dynamic and steady‐state performance of the finite control set model predictive torque controlled surface‐mounted permanent magnet synchronous motor drive system, a novel finite control set model predictive torque control (FCS‐MPTC) with different dynamic and steady‐state control schemes is proposed in this paper. When the SMPMSM drive system operates at transient state, the optimal basic voltage vector of inverter is the vector that minimizes torque tracking error, the proposed FCS‐MPTC achieves fast dynamic response based on the optimal torque control. When the system operates at steady state, the relative importance of torque to the stator flux amplitude is calculated based on the quantitative analysis of minimum staggered errors between motor torque and stator flux amplitude control objectives, then the priority weighting factors based on the relative importance are determined online adaptively, the optimal control of motor torque and stator flux amplitude is achieved simultaneously. Finally, the comparison of the experimental results of proposed FCS‐MPTC with different control methods is implemented and research conclusion is shown. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Linear phase shifting transformer is a new type of phase shifting transformer with the advantages of simple winding structure, easy modularity, and the ability to shift phase at any angle. In order to improve the efficiency and power factor of linear phase shift transformer and reduce the weight of the body, based on the equivalent circuit, this paper first, selects the main design parameters of the linear phase shift transformer model as the optimization object, secondly, selects the constraints and objective function applicable to this model, and then, establishes the linear phase shift transformer optimization design model. Finally, a differential evolutionary algorithm with strong global search performance is used to optimize the design parameters. Taking the 1 kW linear phase shifting transformer as an example, the efficiency, power factor, and weight before and after optimization are compared using finite element simulation to verify the effectiveness of the proposed optimization method. The test results of the experimental prototype prove that the proposed method can effectively solve the optimization design problem of linear phase shifting transformers. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In electromagnetic launcher, the pulsed current is concentrated by contact state, current skin effect (CSE) and velocity skin effect (VSE), and heat the material locally. It will lead to melt or degradation, reducing stability and service life of the launcher. In order to study the current distribution with all these various influences, a 3D transient current analysis model with dynamic conductivity assignment and contact layer is proposed in this paper. It is found that the short contact length in armature moving direction can make two peaks overlap caused by CSE and VSE, and VSE can disturb the current distribution in horizontal direction. When designing armatures, it is recommended that the contact length in the moving direction should be long enough during the entire launch process, so to isolate the two peaks, and that the central length of the armature tail should be longer than the lateral length, so to prevent the current from concentrating more at the lateral edge. These conclusions help the optimization of the launcher structure to reduce local damage caused by current concentration and extend service life. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The traditional 25KV electric railways have various problems such as power quality issues, passing neutral sections, complex storage, and utilization of regenerative braking energy, the medium‐voltage direct current (MVDC) traction power supply system (TPSS) may be a potential alternative electric railway mode and can be freely accessed to the renewable energy and energy storage systems, which is an important development direction of the future low‐carbon RES. This paper first describes the structure and characteristics of the current Railway Electrification System (RES), and then analyzes and summarizes the current research status of the MVDC TPSS topology structure, modeling method, stability criterion, and analysis method and coordination control strategy. Finally, combined with the research status, the development direction of the MVDC TPSS has prospected. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Nowadays, the optical voltage sensor (OVS) has become the best practical solution for the high voltage measurement in modern smart grid. And the polarization of the incident light greatly influences the sensor's measurement accuracy. In this paper, taking the radial polarization optical voltage sensor (RPOVS) as an example, its practical optical model is established by using the theory of polarized optics. The formula of the measurement relative error is obtained, and the influences of the ellipticity and extinction ratio on sensor performance are analyzed in detail. Then the suggestions are given and verified by simulations and experiments, which show the measurement error brought by the polarizer parameters to RPOVS is reduced by about 0.2%, promoting the sensor's realization of 0.2 accuracy class from the aspect of optical path. In addition, this study has certain reference value for other types of OVS and optical polarization measurement. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

For ultra‐high‐voltage (UHV) systems together with high‐voltage facilities, more rationalized insulation coordination and equipment design are required. To this end, making large‐scale and long‐term field lightning‐strike observations, large amount of and practical experiments, and introducing new analysis techniques have enabled the development of advanced technologies capable of transforming conventional techniques. This paper reviews what has been developed in a Japanese electric power company in this regard. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper deduces the quantitative relationship between the flux vectors and the power of power winding (PW) in brushless doubly‐fed reluctance generator (BDFRG). On this basis, the direct power control (DPC) theory of BDFRG is established, which makes up the deficiency that the DPC theory of BDFRG is only based on qualitative analysis in the existing literature. The power derivative expression is derived for accurately analyzing the effect of voltage vector of control winding (CW) on the power of PW, concluding that the control effect of DPC is related to the operation point of a BDFRG. The number of basic voltage vectors of CW connected with two‐level converter is limited, resulting that under some operation conditions, a BDFRG controlled by DPC could present a time interval where the power cannot be controlled satisfactorily. Therefore, the space vector modulation‐based direct power control (SVM‐DPC) strategy of BDFRG is proposed, which can solve the above problem and fix the switching frequency. Experimental results prove the correctness of the elaboration and the proposed method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A calculation model of radial electromagnetic force wave for permanent magnet assisted reluctance motor (PMaSynRM) with rotor slots is proposed in this paper. By introducing complex air gap relative permeance, the improved magnetic potential permeability method is applied to the calculation of electromagnetic force wave of the PMaSynRM. Considering the influence of both stator and rotor slots, the characteristics of electromagnetic force wave are analyzed theoretically. A multi‐physical coupling model of PMaSynRM is established. The natural frequency of the stator core is obtained by modal finite element analysis and modal hammer experiment. The harmonic response is analyzed by loading electromagnetic force wave into the structure field and the vibration on the housing surface is calculated. The results show that although the amplitude of electromagnetic force is small at zero‐order slot frequency, the vibration caused by electromagnetic force at frequency of stator slots and rotor slots, especially at the rotor slot frequency, is the biggest vibration source. The effectiveness and regularity of the calculation model are verified by the prototype vibration experiments. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Because the magnetic circuits of homopolar inductor machines (HIMs) are three‐dimensional (3‐D), a 3‐D finite element model (FEM) is usually built to accurately compute the cogging torque in HIMs, but the drawback is very time‐consuming in modeling and computing. Therefore, a two‐dimensional (2‐D) FEM of HIMs is needed to simplify the computation of the 3‐D FEM. However, the existing odd harmonic 2‐D FEM cannot accurately predict the cogging torque in HIMs. To address this problem, this paper proposes a full‐order harmonic 2‐D FEM. First, the analytical expressions of HIM cogging torque are derived by the combination of energy method and air‐gap field modulation principle. Based on the obtained analytical expressions, the equivalent principles between the 3‐D and 2‐D FEMs are analyzed. According to the above equivalent principles and taking a 48‐slot/4‐tooth (48S4T) permanent magnet (PM) HIM as an example, a full‐order harmonic 2‐D FEM of the example machine excited by a field winding is proposed. The structure of the full‐order harmonic 2‐D FEM is described in detail. The turn number of field winding and field current amplitude of the proposed 2‐D FEM are investigated. The differences between the odd harmonic 2‐D and full‐order harmonic 2‐D FEMs are also analyzed. Finally, the cogging torque in the 48S4T PM HIM with distinct rotor tooth‐arc to tooth‐pitch ratios is computed by 3‐D, odd harmonic 2‐D and full‐order harmonic 2‐D FEMs of the machine, respectively. The results illustrate that compared with the odd harmonic 2‐D FEM, the full‐order harmonic 2‐D FEM can shorten the calculation time and has the similar computation accuracy as the 3‐D FEM. Moreover, the experimental validation is performed on a prototype of the 48S4T PM HIM. The error between the maximum cogging torque obtained by the full‐order harmonic 2‐D FEM and experiments is only 2.12%. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The cooling performance of the machine with the closed liquid cooling system is excellent. However, the electromagnetic characteristics of the oil separator which sealing the cooling oil in the stator side can have a significant impact on the performance of the machine. In this paper, a liquid cooling structure with the magnetic oil separator is proposed. Taking the 20 000 rpm high‐speed permanent magnet generator as an example, the influence of the electromagnetic parameters of the magnetic oil separator on the generator output performance is studied by the analytical calculation and the finite element method, and the mechanism of the nonlinear variation of the generator output performance with the permeability of the oil separator is obtained. The influence of the oil separator on the air‐gap magnetic field and electromagnetic force is analyzed, and the reduction mechanism of the different permeability of the oil separator on the harmonic magnetic field and radial force is revealed. The vibration acceleration response of the generator stator is obtained through the modal and harmonic response analysis, it is confirmed that the magnetic oil separator has the effect of reducing vibration. In addition, the 3‐D temperature field calculation model of the generator is established, the influence of the thermal parameters of the oil separator on the internal heat exchange of the generator is studied, and the temperature distribution is obtained. Finally, experiments on the electromagnetic performance and temperature rise of the prototype are carried out to verify the correctness of the theoretical analysis. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A nonlinear filter is presented by using a formal linearization method and the extended Kalman filter (EKF) approach in this paper. A given nonlinear system is transformed into an augmented nonlinear system by considering the higher‐order polynomial terms of state as new additional states. And then, the EKF theory is applied to it well. Numerical experiments show the effectiveness of this new filter. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

With the continuous development of intelligent refrigerators, users are having higher and higher requirements for smart management of refrigerator contents. When using traditional machine learning algorithms to deal with refrigerator ingredients classification, problems such as slow recognition speed and low accuracy would often arise. At the same time, the classification accuracy is easily affected by the location of the content. Therefore, this paper uses continuous asymmetric convolutions and depthwise separable convolutions to improve the original Inception model and builds a classification prediction network based on the improved Inception model. The steps to applying the said model is as follows: First, we put the Radio Frequency Identification (RFID) tag on the food in the refrigerator, and then we collect the antenna data RSSI received by each tag through the reader. Finally, the RSSI is preprocessed and entered into the classification network to determine the location of the label. The proposed classification network has the advantages of possessing a simple structure, easy expansion of network depth, and fewer training parameters. The experimental results show that compared with other machine learning algorithms and pure convolution networks, the lightweight network model based on the improved Inception structure demonstrates great superiority. Compared with the original Inception structure, the enhanced network model is more lightweight. The number of parameters is reduced by 50%, and the amount of float‐point operations is reduced by 34%. Meanwhile, the accuracy of the lightweight model has been improved by 0.6%. Thus the improved model has better prediction performance in the classification of refrigerator content. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Brushless doubly‐fed air‐core pulse alternator (BDAPA) is a new type of pulse alternator. It does not need a brush and slip ring, improving the reliability of the system. Moreover, the field winding and rotor winding have good compensation effect, which can significantly improve the discharge performance of the pulse alternator. As a high‐power pulse power supply, BDAPA must have a set of corresponding excitation power supplies to control its excitation. Pulse alternator and excitation power supply constitute the pulse alternator power supply system. The excitation power supply of pulse alternator usually adopts a pulse capacitor, the field winding of pulse alternator is excited by the pre‐charged capacitor before the pulse alternator discharges the load. After discharging, the excitation capacitor must be charged again before the next work of pulse alternator. This requires an additional set of DC power supply to charge the excitation capacitor. It not only increases the volume of the whole system and reduces the energy storage density of the system, but also makes the control of the system more complex. Taking the BDAPA as the research object, this paper proposes a control method with energy feedback, which is combining self‐excitation and separate excitation. Using the inertial energy storage of the pulse alternator and the inductive energy storage of the field winding and rotor winding, the excitation capacitor can be recharged through proper control methods, which can save the DC excitation power supply and improve the energy storage density of the system. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Packaging and die bonding of conventional micro‐electro‐mechanical‐systems (MEMS) and semiconductor devices include separate dispensing, mounting and heating curing. A novel die bonder's work stage and temperature control method are proposed so that dispensing, mounting and heating curing can be completed at the same station. This paper introduces the working principle of the thermopile sensor and the requirements for temperature change during die bonding, analyses the main structure and working process of the novel die bonding stage, and uses commercial finite element analysis software to evaluate the temperature field of the novel die bonding stage and devices during the process of heating, holding and cooling to provide process guidance for accurate temperature control of die bonding. Dispensing, mounting and heating curing are integrated in the same station, avoiding the position error of devices when transferring, reducing the number of equipment and floor area, and effectively saving production costs. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The short‐circuit withstand capability of the transformer is crucial to the reliability of power systems. Research on the short‐circuit characteristics of windings is the basis for improving the stability of power transformers. Although many studies focus on electromagnetic force and cumulative deformation of two‐winding transformers, there is a lack of careful comparison of the electromagnetic and mechanical characteristics of three‐winding transformers, as well as the cumulative effect of stress, displacement and strain. In this paper, the model is established to study temporal response and spatial distribution of the electromagnetic and mechanical properties under short‐circuit impacts. The results show that the short‐circuit effects on medium and low‐voltage windings are more severe than on high‐voltage windings. The first current peak will lead to the greatest threat. Second, the influences of iron core and pre‐stress on short‐circuit characteristics are investigated. The characteristics of windings differ between inside and outside the iron core window, which is pronounced for high‐voltage winding. Besides, the greater pre‐stress is not better for the stability of windings. Finally, it is found that the residual stress and displacement continue to accumulate and the plastic strain appears under multiple short‐circuit impacts. This work is helpful for the analysis of short‐circuit withstand capability of transformers. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The dual‐stator permanent magnet (PM) machine has the advantages of high torque density, high efficiency, and compact size, which makes it suitable for low‐speed high‐torque applications. A dual‐stator low‐speed high‐torque permanent magnet drive machine (DLHPMDM) is discussed and studied in this paper, which is applied to the ball mill application. First, in order to meet the requirements of high efficiency and high reliability, a DLHPMDM with the inner and outer windings connected in parallel is obtained through the designs carried out in terms of the magnetic circuit structure, structural size, and the pole‐slot number combination. However, for the DLHPMDM with the inner and outer windings connected in parallel, the power allocation between the inner and outer machines is a critical problem that needs to be accurately analyzed, and the circulating current between the two sets of windings is also a particular issue that merit attention. Therefore, a new modeling method is proposed for the DLHPMDM to solve such cases more accurately. The proposed new method combines the advantages of the rapidity of the finite element analysis (FEA) with current excitations and the accuracy of the FEA with voltage excitations. Finally, a prototype of the DLHPMDM is manufactured and tested. The feasibility of the design theory and the validity of the proposed modeling method is verified by both the tested and simulated results. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A practical method is proposed in this paper for analysis of the lightning transient in the grounding grids. The circuit parameters of the grounding electrodes are evaluated by a set of analytic formulas, in which the soil ionization effect is taken into account. By means of the circuit parameters, the grounding electrode segments are represented by the π‐type circuits and a circuit model is built for the grounding grids. The lightning transient responses in the grounding grids can be calculated from the circuit model. The calculated results are compared with the measured ones to check the validity of the circuit model. In view of the actual distribution randomness, the lightning current amplitude is taken as a random variable and a statistical algorithm is further presented for statistical analysis of the lightning transient in the grounding grids. In the algorithm, the accumulative probability function is introduced to describe the random distribution of the lightning current amplitude. The lightning transient responses calculated in a large interval of the lightning current amplitude are weighted by the corresponding probability density. Then, the statistical values of the lightning transient responses can be obtained from the weighted sum. A numerical example is also given to discuss the difference between the statistical values and the nonstatistical ones calculated by the conventional method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In order to mitigate the negative impact brought by the large‐scale grid connection of EVs, it is highly significant to study the optimal charging scheduling strategy of EVs. In this paper, a multiobjective optimization model of ordered charging and discharging with the participation of distribution network operator (DNO), charging station operator (CSO) and EV users is established, which maximize the interest of three parties. At the same time, the real‐time price (RTP) based on the change in load rate is designed and compared with the time‐of‐use (TOU) price model to analyze the impact of both on the interests of all parties. At last, the sparrow search algorithm (SSA) is introduced and three improvements are made. The results demonstrate that different charging modes of EVs and charging price models will affect the balance of interests of the three parties, while the improved SSA performs better under different users' response rates. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Soil properties have been known to be the factors that influence the ionization process in soil, which cause the impulse impedance, Zimpulse to be lower than that at steady state resistance, RDC. Many studies have established the relationship between the percentage reduction of Zimpulse from RDC in such that the percentage reduction is more pronounced in high resistivity soil, or in high RDC, than that at low resistivity soils. Nevertheless, Zimpulse is not the only parameter in representing the characteristics of soil under high impulse conditions, where from the voltage and current waveforms, the current rise and discharged times can also be established, where more accurate and extensive analysis of the electrical characteristics of ground electrodes subjected to high impulse currents can be achieved. This paper presents the experimental results of four ground electrodes, installed in agricultural land, with soil resistivity, of below 3 Ωm, subjected to high impulse currents, where the parameters of current rise times, Zimpulse and current discharged times were investigated. Two of these ground electrodes are having close RDC values, despite having different electrode's configurations, were also investigated. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Research on global harmonic mitigation against distributed and high‐proportioned nonlinear loads in modern distribution networks has received extensive attention. In this paper, a distributed compensation method for active power filters (APFs) is proposed, which utilizes a small number of APFs with adjustable reference to alleviate the global voltage distortion caused by a large number of distributed nonlinear loads. The model predictive control (MPC) is employed to calculate the optimal current reference for compensators at each optimization moment by predicting the system's performance in a certain future time period. Furthermore, the Kalman filter (KF) algorithm is used to estimate the initial harmonic voltage for the MPC, reducing the unfavorable effects of the model uncertainty and measurement noise. The test results based on a seven‐bus distribution network in MATLAB are provided to verify the effectiveness of the proposed method. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, the robust control problem is investigated for fractional‐order nonlinear systems(FONS) with the unknown‐but‐bounded parametric uncertainties and the external disturbances. First, an H∞$$ {H}_{\infty } $$ adaptive observer is designed to estimate the system states and the unknown parameters. Then based on the observer, a fractional‐order sliding mode controller is designed and the asymptotic stability sufficient condition is derived for the closed‐loop system on the basis of Lyapunov stability criterion. The control strategy can not only realize the system stabilization, but also estimate the system unknown parameters and the system states. Moreover, a fractional‐order power type continuous function is adopted to replace the traditional sign function in the switch control component, the proposed method can avoid the chattering phenomenon. Finally, the simulation results demonstrate the feasibility and effectiveness of the presented method. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Population‐based evolutionary algorithms are suitable for solving multi‐objective optimization problems involving multiple conflicting objectives. This is because a set of well‐distributed solutions can be obtained by a single run, which approximate the optimal tradeoff among the objectives. Over the past three decades, evolutionary multi‐objective optimization has been intensively studied and used in various real‐world applications. However, evolutionary multi‐objective optimization faces various difficulties as the number of objectives increases. The simultaneous optimization of more than three objectives, which is called many‐objective optimization, has attracted considerable research attention. This paper explains various difficulties in evolutionary many‐objective optimization, reviews representative approaches, and discusses their effects and limitations. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

When designing a controller based on a fuzzy model composed of fuzzy rules, in most cases controllers are designed only based on the consequent parts of the fuzzy rules, equally meaning the information of the antecedent parts is merely ignored. This paper first partitions all of the rules into two groups based on the information of the antecedent parts, in which one contains certain rules around the origin, and the other is a group of rules away from the origin. While being able to make the former arbitrarily small, each rule of the latter leads to a favorable quadratic inequality, which will be useful in controller design by the help of the S‐procedure. On the other hand, while the affine T‐S fuzzy model is much more effective for describing the dynamics of the system concerned in comparison with the regular T‐S fuzzy model, it encounters some difficulties when designing a controller based on the model because of the affine terms within. This paper makes clear that the difficulties can be overcame by using the quadratic inequalities based on the fuzzy rule partition. In addition, the effectiveness of the approach is demonstrated by applying it to the CSTR for an exothermic irreversible reaction. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Particle swarm optimization (PSO) is a popular optimization technique known for its simplicity and effectiveness. This paper introduces a variant that achieves a better balance between exploration and exploitation, named DiPSO. DiPSO incorporates a novel strategy based on trends in mean distance between individuals for local exploitation control. Experiments on 29 benchmark functions demonstrate that DiPSO consistently outperforms the state‐of‐the‐art variant of PSO. Convergence analysis reveals that DiPSO achieves faster convergence and superior solutions. These results highlight the effectiveness of DiPSO in solving optimization problems. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper proposes a three‐layer coordinated optimization strategy based on fuzzy control of renewable energy sources (RESs), vehicle‐to‐grid (V2G) and energy storage. Firstly, the overall structure of this strategy is introduced, which is composed of V2G management system, renewable energy dispatching system and energy storage (ES) real‐time balancing system. Secondly, the control strategy is proposed for different systems, among them, the V2G management system considers shortage of power grid, forecasted maximum output of RESs, and state of charge (SOC) of electric vehicles (EVs) to calculate the charging plan for each EV in next time interval by fuzzy control algorithm; The renewable energy management system gets the expected shortage state of the power grid in the next period according to the charging plan and the current state of the power grid, then combined with the battery state of the energy storage system, the renewable energy guiding power generation in the next period can be calculated by the fuzzy control algorithm; The energy storage real‐time balancing system can charge or discharge according to the real‐time frequency and shortage of power grid to ensure balance between supply and demand of power grid. Finally, the simulation proves that the three‐layer management strategy proposed in this paper can help grid to cut peak and fill valley effectively, improve the load characteristics of the regional power grid and reduce the amounts of the rejected renewable energy. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper is aimed at improve accuracy of angular position synchronization control of Permanent Magnet Synchronous Motor driving system. Traditional PID controller could not meet requirement due to poor dynamic characteristics. The Global Fast Terminal Sliding Mode Control (GFTSMC) has good ant‐disturbance ability, could make system more robust and realize synchronization control of angular position. But due to error in load torque observation, system state convergence error will be caused, which will reduce the accuracy of synchronization. In this paper, fractional‐order differentiation is used to replace the nonlinear part of GFTSMC, constructed Fractional Order Differentiation—GFTSMC (FOD‐GFTSMC) controller to improve accuracy of synchronization. Theoretical analysis will be used to demonstrate that this control strategy could improve convergence accuracy of system state, reduces error of synchronization, and some experiments will be carried out to verify that this kind of controller has high synchronization accuracy, fast dynamic response ability and strong robustness. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In rural areas due to the low capacity of resources on the one hand and the increase in demand, on the other hand, the use of load management will be a little different. In this paper, load energy management programs considering three modes are used to minimize the cost of operating a rural multi‐microgrid system and increase the accessibility of its controllable load. Consumers in this paper are divided into two sets of controllable and uncontrollable loads, and microgrids will respond economically to the energy management system due to the capacity of renewable resources and distributed generation. Consumption coordination in the form of an optimization program with a mixed‐integer nonlinear programming mathematical model is designed to reduce the overall operating costs in the microgrid. For microgrid's lowest cost, three different scenarios including only the use of uncontrollable loads, simultaneous use of uncontrollable and controllable loads, and the use of adjustable generation sources with considering generation ceiling of distributed generation have been used. Simulations have been performed in different scenarios in a modified IEEE 33 bus system in the GAMS environment with different solvers to achieve the best response, which shows a significant reduction by LINDO and DECOPT solver. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Point‐of‐interest (POI) recommendation has always faced serious data sparsity problem. Most of the existing POI recommendation methods do not consider the bidirectional relationship between the user‐preference for locations and the location‐ attractiveness to users in the original dataset when solving the sparsity. For this problem, a point‐of‐interest recommendation method based on bidirectional matrix and deep belief network (POI_DBNBM) is proposed in this paper. Specially, from the perspectives of users and locations, we first construct two different matrices with bidirectional relationship by mapping the original dataset, and we use deep belief network (DBN) with strong learning ability to predict the two matrices. Then, a local–global weight optimization method is developed to weight and fuse the two result matrices obtained by DBN, so as to achieve the more precise user's rating prediction matrix for locations. The abundant experimental studies and evaluations are conducted on FourSquare dataset. Results are encouraging and better than those previously reported on the dataset. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, a new dual mode blind equalization method using neighborhood symbol‐based decision and decision‐directed (NSBD‐DD) algorithm is proposed to equalize the satellite communication signals. The proposed algorithm adopts the combined cost function to employ the advantages of symbol decision algorithm and the decision‐directed algorithm, which can further improve the universality of the proposed algorithm. Compared with the conventional blind equalization algorithm, the compensation ability of intersymbol interference and convergence speed of the proposed algorithm can be improved simultaneously. To verify the performance of the proposed algorithm, the computer simulation is performed, and the simulation results show that the residual intersymbol interference of the 64QAM signals can be decreased to −50 dB under the satellite channel, which has 30 dB lower than multi‐modulus algorithm (MMA), 26 dB lower than NSBD algorithm, and 10 dB lower than SBD algorithm. And compared with SBD algorithm, the number of iterations required for the NSBD‐DD algorithm can be decreased from 8000 iterations to 6000 iterations, which convergence speed is increased by 25%. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Dynamic neural networks (DNNs) are widely used in data‐driven modeling of nonlinear control systems. Due to the complexity of the actual operating nonlinear power systems, rigorous dynamic models are always unknown. DNNs can focus on methods that only use input and output information to establish accurate dynamic models and reduce noise in measured data, which is called data‐driven modeling. The core of the DNN is the feedback with memory function. This paper analyzes the traditional Elman neural network (ENN) and nonlinear auto‐regression with exogenous input (NARX) neural network with different structure feedback structures, and proposes a full feedback dynamic neural network (FF‐DNN) with exogenous input. Eight different kinds of neural networks (including ENN, NARX, etc.) are compared and analyzed. The eight kinds of neural networks are applied on the experimental data of the DC‐AC inverter and the power system of Zhejiang Juchuang Smart Technology Company Park in Wenzhou. The experimental results are used to compare the performance of the data‐driven models established by eight different kinds of neural networks under different noise conditions, verify the robustness and generalization performance of dynamic data‐driven modeling based on FF‐DNN, and demonstrate the feasibility and effectiveness of FF‐DNN in actual power systems. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper presents a novel frequency compensation scheme for the stability of low dropout regulator (LDO). The proposed compensation scheme introduces a zero in the voltage regulation loop to enlarge gain and phase margin at high‐frequencies. As a result, high open‐loop‐gain and improved load regulation performances are achieved, and a particular resistor is introduced in the compensation structure to cancel the voltage drop originating from cable resistances at the output to further improve the load regulation performance. The proposed LDO with wide input/output range and high‐power supply rejection is designed and implemented in a 180 nm CMOS process. The LDO operates with an input voltage range of 4–16 V, an output voltage range of 1.5–5 V and an output current range of 0–1000 mA. High open loop gain and high bandwidth are achieved, and the simulated performances of load regulation and line regulation are less than 32 μV/mA and less than 3 mV/V over the whole operation range, respectively. The on‐chip compensation capacitor required by the compensation module is only 1.8 pF. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

For the initial attachment parts of the human body discharge under live working conditions of transmission lines, this paper proposes a calculation method suitable for any working posture and tower type based on the leader discharge theory. By simulating the formation of the leader channel, the minimum background field for the initiation of the stable leader in various parts of the human body is calculated, and the probability distribution of the initial discharge attachment position on the body surface of the worker is obtained. The results show that the stable transformation of the secondary corona to the leader channel at the tip of the human body is a precondition for this part to become an attachment point of the discharge; In the process of the worker entering the equipotential, affected by the entering direction and posture, the parts with a large curvature such as the hands and feet are likely to become the initial discharge attachment position; Due to the shielding effect from the limbs, the rear part of the worker has a low probability of becoming the initial discharge attachment position. The purpose of this research is to explore an effective method for identifying the discharge location of a live line worker, and to strengthen the protection of workers from the electric field. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this work, we investigated strength variations of the ventriloquism effect when the loudspeaker's position was indicated to the subject. The ventriloquism effect is an audiovisual cross‐modality in which a sound is heard from the position of an image, even though the sound and image are presented at different locations. Previously, this effect has been studied under conditions where the sound location is not revealed. In contrast, this paper proposes measuring the ventriloquism effect using a single loudspeaker displayed as a 3D scanned image in the background of a virtual reality (VR) image. The angular discrimination threshold (the perceived angle of disparity between the sound and the image shifted horizontally) was employed to evaluate the ventriloquism effect. The resulting ventriloquism effect was compared to the effect noted in a previous study, where measurements were conducted without revealing the loudspeaker's position to the subjects. The results indicate that revealing the loudspeaker's position emphasizes the ventriloquism effect. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper proposes a controller for single‐phase synchronous inverters (SSIs) that was designed to stabilize the performance of a grid while providing overcurrent protection during the occurrence of a fault. The proposed controller for an SSI eliminates the multiple feedback control loops consisting of voltage and current controllers under normal conditions to avoid the instability attributed to them. To output the designed voltage precisely calculated using the core circuit, including a swing equation and speed governor, we employ the latched limit strategy for the overcurrent protection, which is combined with a proportional resonance current controller. Numerical simulations and experiments demonstrated that the proposed controller provides the designed performance while ensuring overcurrent protection during normal operation. © 2023 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A novel duty‐cycle‐sensing overload detector for DC‐DC converter is proposed in this paper. Firstly, the theoretical analysis is conducted to reveal the susceptibility of the conventional overload detectors to temperature variation and the input/output‐voltage change of the DC‐DC converter. Then, the schematic of the novel duty‐cycle‐sensing overload detector is presented and its operation principle is analyzed. Thanks to the time register, the proposed detector generates a theoretically voltage‐and‐temperature‐insensitive threshold duty cycle, compares it with the real‐time duty cycle of the converter's PWM signal, and announces an overload event if the real‐time duty cycle exceeds the threshold. Finally, a prototype of a BUCK DC‐DC converter including the proposed detector and a conventional current‐sensing overload detector is constructed and measured. As the measurement results show, the threshold duty cycle only varies by about 2.4% as the temperature changes from 0 to 90 °C while the threshold voltage of the conventional current‐sensing detector changes by about 4.6%. The proposed detector can keep effective even the temperature rises to 90 °C while the conventional current‐sensing detector can work at a temperature no higher than 85 °C. Without circuitry modification, the proposed detector correctly senses the overload event as the DC‐DC converter's output voltage changes in a range of 2.1–2.9 V while the conventional one loses its effectiveness if the output voltage is set higher than 2.54 V. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Future labor forces are anticipated to include collaborative robots that work alongside humans in the same environment. Proximity and tactile sensors are among the most important devices for collaborative robots to operate safely. In this paper, we propose a proximity and tactile sensor for a collaborative robot that combines multiple time‐of‐flight (ToF) sensors and a self‐capacitating proximity and tactile sensor. ToF sensors can detect the distance to an object and have a long measurement range. However, at close distances, their detection accuracy deteriorates, and blind spots may likely not be detected. Conversely, the self‐capacitance proximity and tactile sensor detect objects within the blind spots of ToF sensors and contact conditions because the sensor can detect an object before and after contact, being highly sensitive in the proximity range. In the proposed sensor, the electrodes of the self‐capacitance are enlarged, and multiple ToF sensors are used to expand the measurement range and reduce blind spots. A prototype sensor was seamlessly able to measure objects from approximately 400 mm to contact conditions. In addition, the robot arm with the prototype sensor could be controlled in real time using the measured data of the sensor. Therefore, we believe that the proposed sensor can be potentially used as a proximity and tactile sensor for collaborative robots. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Stimulus reconstruction decodes the listener's auditory attention through the greater neural tracking of the attended speech over the unattended stream. While acoustic features of speech are vital to the listening task and comprehension, very few studies have analyzed the effects of acoustic features of speech on stimulus reconstruction. This paper investigates approaches of stimulus reconstruction, where correlations between the neurally decoded and actual speech envelopes are calculated from specific speech segments, varying in transient levels as measured by spectral transition measures. Additionally, two methods of calculating correlations were adopted enabling analysis of the effects of relatively lower and higher frequency components of the speech envelope. Correlation after concatenation analysis showed that STM level of only the attended speech affected decoding performance, hinting at a top‐down attentional effect. A bottom‐up effect of salient aspects of speech momentarily dominating neural entrainment was also inferred from the weighted mean of multiple correlations. Future studies on the link between acoustic features of speech and its corresponding neural tracking behavior are suggested. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In the actual power grid environment, there are severe class imbalances in the data sets of various monitoring systems. The existing deep learning methods are highly dependent on the training data sets, and it is difficult to mine the minority sample features in the imbalanced data sets, resulting in Classification recognition accuracy is severely limited. This paper takes the voltage sag as the research object, and proposes a dataset enhancement method based on an improved balanced generative adversarial network. This method combines the advantages of autoencoder and generative adversarial network, learns the public knowledge in the data set through the initialization training of autoencoder, and uses the majority class sample features to assist in generating minority class samples. In addition, an embedding layer is introduced into the self‐encoder architecture to add label information to the eigenvectors, which solves the problem of strong coupling between the distribution of voltage sag eigenvectors and improves the generation effect of samples. At the same time, the Wasserstein distance optimized by the gradient penalty term is used to guide the model adversarial training, which overcomes the problems of vanishing gradient and mode collapse of the original model. Through experimental analysis, the model can fully extract the features of minority samples under unbalanced data sets, ensure the distribution consistency between generated samples and original samples, and take into account the authenticity and diversity of generated samples, which can effectively improve the recognition effect of deep learning model on minority classes and improve the overall recognition accuracy. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Vehicle routing problem (VRP) is one of the classic combinatorial optimization problems where an optimal tour to visit customers is required with a minimum total cost in the presence of some constraints. Recently, VRP is being solved with the use of deep reinforcement learning (DRL), with node sets considered (represented) as a graph structure. Existing Transformer based DRL solutions for VRP rely only on node information ignoring the role of information on the edges between nodes in the graph structure. In this paper, we proposed an attention‐based end‐to‐end DRL model to solve VRP which embeds edge information between nodes for rich graph representation learning. We used Transformer based encoder‐decoder framework with an edge information embedded multi‐head attention (EEMHA) layer in the encoder. The EEMHA‐based encoder learns underlying structure of the graph and generates an expressive graph topology representation by merging node and edge information. We trained our model using proximal policy optimization (PPO) with some code‐level optimization techniques. We conducted an experiment on randomly generated instances and on a real‐world data generated from road networks to verify the performance of our proposed model. The result from all experiments show that our model performs better than the existing DRL methods and most of the conventional heuristics with good generalizability from random instance training to real‐world instance testing of different problem size. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The current‐limiting reactor is currently the most used fault current limiting technique to ensure the fault ride‐through of the multi‐terminal dc grid. However, its configuration will significantly prolong the fault current clearance time and increase the dissipated energy of dc circuit breakers. Therefore, this paper proposes a cost‐effective multiline fault current limiter for multiport application in multi‐terminal dc grids, which can effectively limit the rising speed of fault current through the integrated current‐limiting reactors without time delay and significantly reduce their negative impacts on the performance of dc circuit breakers by bypassing the current‐limiting reactors through the solid‐state switch units during the fault current interruption process. The topology and operation process of the multiline fault current limiter are introduced at first. Then, the economic comparison of the proposed device with the existing solutions is presented. Finally, the feasibility and superiorities of the proposed device are verified by extensive simulations and scaled‐down experiments. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]