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The antenna cabin is a strong scattering source of various military platforms, and its stealth effect directly affects the stealth effect of military platforms such as missiles. Aiming at limitations of stealth FSS radome, design method of absorbing electromagnetic window structure is carried out in this paper. Based on the transmission line model, this paper introduces its working mechanism, proposes an analytical method and a complete design method. The structure proposed in this paper realizes pass-band at X-band (8-10GHz) and absorption in S-band (2-4GHz). After a series of simulations and optimizations, at least 10dB absorption in S-band and less than 1 dB insert loss in 8-10GHz are realized. [ABSTRACT FROM AUTHOR]

In this article, a novel transmission line model consisting of open stubs and a one-end connected coupled line is introduced as an alternative to the standard quarter wavelength transmission line (QWTL). The new transmission line unit is used to realize a highly compact branch-line balun. Even and odd mode analysis is employed to extract the closed-form design equations. To substantiate the theoretical analysis, a branch-line balun with f 0 = 0.9 GHz is implemented on a biodegradable substrate material and tested. The developed prototype is having a relative circuit area of 11.2% of the conventional balun. The measured results exhibit that the return loss is better than 20 dB. A good match is found between the simulated and tested results. [ABSTRACT FROM AUTHOR]

This paper exhibits the design and implementation of a compact dual-band bandpass filter on paper substrate. The proposed filter which works on the principle of signal interference technique has a parallel combination of short-circuited coupled line and an H-shaped network of transmission lines with open stubs. Due to the superposition of signals of the two transmission paths, a second order dual-band bandpass response with four transmission zeroes is achieved. To validate the proposed design, theoretical analysis using the lossless transmission line model is carried out and acknowledged. The developed dual-band filter prototype with center frequencies 1.17 GHz and 4.06 GHz has 3-dB fractional bandwidths of 82.56% (0.69–1.656 GHz) and 20.59% (3.645–4.481 GHz), respectively. The simulated and experimental results are in good congruence with each other. The proposed dual-band bandpass filter can be used in various wireless applications, for example, Global System for Mobile Communications (880–915 MHz), Aircraft surveillance (960–1215 MHz), Indian Regional Navigation Satellite System (1.164–1.188 GHz), Amateur radio (1.24–1.30 GHz), Global Positioning System (1.559–1.61 GHz), Satellite phones (1.616–1.626 GHz), and Satellite communication (3.7–4.2 GHz). [ABSTRACT FROM AUTHOR]

As a large percentage of faults in transmission lines are single-line-to-ground (SLG) and transient in nature, the use of adaptive single-phase auto-reclosing (ASPAR) schemes is essential. In this paper, a new scheme for ASPAR is proposed to improve the stability and reliability of power transmission lines. The proposed approach distinguishes between the transient and permanent faults by using the feature of Stationary Wavelet Transform (SWT) and Gate Recurrent Unit (GRU) deep artificial neural network. Also, by utilizing another GRU network, the proposed scheme predicts the extinction time of the secondary arc (SA) one power cycle before the complete extinction. This can increase the speed of the faulty phase reclosing in the case of a transient fault. Simulation results carried out on a 400 kV power transmission line in the EMTP-RV and MATLAB software environments illustrate that the F 1 score of the proposed ASPAR in classifying the faults is 99.55 %, and its average error in predicting the extinction time of the SA based on the root mean square error (RMSE) criterion is 0.0557. Also, the superiority and high-quality performance of the proposed protection scheme are demonstrated by comparing the results with several state-of-the-art methods. [ABSTRACT FROM AUTHOR]

This review article on switching overvoltage modelling in UHV AC Transmission lines, provides a state-of-the-art analysis of switching overvoltages and their impact on insulation coordination in UHV AC transmission lines. Switching overvoltages, insulation coordination, switching transient modelling tools, and switching surge flashover rate mathematical models are examined in the paper. It also examines modelling concepts, transmission models, insulation coordination for Ultra High Voltage (UHV) versus Extra High Voltage (EHV) lines, simulation scenarios and platforms, and best practices for insulation coordination limited to transmission lines. The methodology involved extensive research, consulting academic journals and conference papers, and modelling switching overvoltages with a case study. Key findings show that transmission tower insulation decreases because actual switching overvoltages take longer time to reach their peak than the critical wave. Every switching action generates a switching overvoltage with a characteristic waveform, which impacts insulation coordination. The work reveals a gap in existing research, which often focuses on overvoltages generated by a few switching events. This review suggests considering overvoltages from primary switching operations for better assessment of insulation coordination. These aspects must be considered in insulation coordination to improve UHV AC transmission line reliability and security. • This review article presents an overview of the available literature on insulation coordination for UHV AC lines covering the various types of switching overvoltages that can occur in UHV AC lines. • This review article also provides a comprehensive overview of the current state of insulation coordination for UHV AC lines and highlights the importance of considering the switching overvoltages and four significant switching operations in the insulation coordination process. • This article also presents a comprehensive view of the modelling guidelines for modelling the UHV AC transmission system and a helps in choosing the right model for the transmission line. • A brief summary of simulation cases and simulation Platforms used for Switching Transients Studies is also presented based on the literature from 1962 to 2024. [ABSTRACT FROM AUTHOR]

Insulators are vital components used in electrical transmission lines. It's crucial to keep their production cost low since they are widely used in electricity transmission. Instead of expensive alumina-based insulators, we can make cheaper ones using clay and bauxite found in nature. Adding more alumina makes them stronger, which is important for high voltage transmission. This paper aims to study the production process of bauxite-based insulators. We examined the insulators' structure using SEM images and EDAX spectrum analysis to see their formations, porosity ratio, and density. This research helps us learn more about these insulators and how they can be used effectively for high voltage transmission lines. [ABSTRACT FROM AUTHOR]

In a neutral, flexible, grounded distribution network, the phenomenon that a single-phase ground fault with high impedance connected in parallel with a low resistance can result in a relatively lower zero-sequence current flowing through the faulty feeder. This zero-sequence current can make it a challenge to use zero-sequence protection schemes to accurately identify and effectively protect the faulty feeder. In terms of the aforementioned challenge, based on the zero-sequence equivalent circuit of a single-phase-to-earth fault, this paper conducts an investigation on the phase difference between the zero-sequence current and the non-fault phase line voltage at power frequency in flexible grounding distribution network with different grounded conditions, both before and after the introduction of a parallel low-resistor connection. Subsequently, a criterion for selecting the faulty feeder is developed based on the observed phase difference characteristics following the implementation of the parallel low-resistor connection. Furthermore, a disposal strategy for single-phase-to-earth faults is formulated, which takes fault resistance estimation into account. To validate the proposed method, a simulation model of a flexible grounding distribution network is implemented with PSCAD/EMTDC. The effectiveness and reliability of this method in multiple scenes, including the initial fault conditions, sampling frequency, and distributed generation (DG), are proved through simulation results. [ABSTRACT FROM AUTHOR]

The training method for deep neural networks mainly adopts the gradient descent (GD) method. These methods, however, are very sensitive to initialization and hyperparameters. In this paper, an enhanced gradient descent method guided by the trajectory-based method for training deep neural networks, termed the Trajectory Unified Framework (TJU) method, is presented. From a theoretical viewpoint, the robustness of the TJU-based method is supported by an analytical basis presented in the paper. From a computational viewpoint, a TJU methodology consisting of a Block-Diagonal-Pseudo-Transient-Continuation method and a gradient descent method, termed the TJU-GD method, for training deep neural networks is added to obtain high-quality results. Furthermore, to resolve the issue of imbalanced classification, a TJU-Focal-GD method is developed and evaluated. Experimental numerical evaluation of the proposed TJU-GD on various public datasets reveals that the proposed method can achieve great improvements over baseline methods. Specifically, the proposed TJU-Focal-GD also possesses several advantages over other methods for a class of imbalanced datasets from the homemade power line inspection dataset (PLID). [ABSTRACT FROM AUTHOR]

For the model of a multi-node energy market, the problem of maximizing social welfare is considered. Social welfare refers to the difference between the total utility of consumption and total production and transportation costs. Algorithms for solving this problem are proposed in our previous papers. These algorithms can be used to assess the prospects for gasification of arbitrary non-gasified regions of the country, if estimates of the initial parameters of the model are known - the functions of production costs and demand in nodes and the functions of transmission costs in lines. In this paper, methods for obtaining such estimates are proposed, as well as the results of the analysis of the prospects for gasification of Irkutsk oblast obtained using the described approaches are presented. [ABSTRACT FROM AUTHOR]

This paper investigates the impact of earth continuity conductor (ECC) placement in duct banks for triangular and flat configurations of three-phase single-core underground cables using the single-point bonding method. Several works in the literature suggest that the ECC should be placed on the right side of the duct/trench for half of the underground transmission line (UGTL) and on the left side for the remaining length, implying the necessity of ECC transposition. However, this technique poses significant civil engineering challenges, requiring extensive work that increases the cost and construction time of the UGTL. Therefore, it is essential to propose a better ECC position that mitigates these problems while satisfying electrical, civil, and safety requirements. To address these issues, this study proposes a better ECC position that meets electrical, civil, and safety requirements while minimizing induced voltage on the sheath and induced current in the ECC. We focus on an underground transmission line operating at 220 kV, evaluating both triangular and flat configurations. The paper employs accurate formulations for the series impedance calculation of the cable and computes the induced factors under steady-state conditions, considering practical aspects such as civil works and ease of installation. Our findings indicate that in triangular formations, the optimal ECC position is precisely in the middle of the cables. This placement minimizes induced current and voltage on the sheath, eliminating the need for ECC transposition, contrasting with IEEE 575 guidelines. Conversely, ECC transposition is crucial for flat formations to minimize circulating current. Our study recommends placing the ECC at the top of the duct at a specific distance, differing from IEEE 575 and CIGRE 531 guidelines. When ECC transposition is performed, the induced voltage on the sheath can be calculated as if the ECC were not present. • Investigated optimal ECC placement in a duct for 220 kV underground lines. • Found that in triangular formation, mid-position ECC minimizes sheath voltage. • Contrasted findings with IEEE575, show optimal ECC position deviates from guidelines. • In flat formation, crucial ECC transposition identified, place ECC at duct top. • ECC transposition allows sheath voltage calculation as if ECC absent. [ABSTRACT FROM AUTHOR]

The lightning performance of transmission lines is a criterion of utmost importance to be evaluated in transmission system reliability. In order to accurately estimate the expected number of shutdowns, it is imperative to account for the stochastic nature of the lightning phenomenon. In this sense, the most widely used technique to estimate these shutdowns is the Monte Carlo method (MCM). Although the MCM is a trustful method, it has a huge drawback in terms of computational burden. Therefore, this paper proposes the use of an alternative statistical technique, the Unscented Transform method (UTM). This method achieves an approximate non-linear mapping by employing a set of points (associated with input statistical data), which are deterministically selected and weighted. The set of these points and weights is then used to estimate the lightning overvoltage across insulator strings, which represents a significant reduction in the number of samples evaluated in the process in relation to the application from MCM. In this paper, the MCM and UTM methods are applied and compared in the lightning overvoltage evaluation, which is carried out with the help of the Alternative Transient Program (ATP). From the studies conducted, it was found that the application of UTM in place of MCM allowed for significant computational gains while maintaining satisfactory levels of accuracy in the estimation of indicators. • Unscented Transform applied to transmission line lightning performance estimation. • Monte Carlo applied to transmission line lightning performance estimation. • Accelerating the assessment process of transmission line lightning performance. • Monte Carlo and Unscented Transform performance in lightning-related study. [ABSTRACT FROM AUTHOR]

Interline DC Power Flow Controllers (IDCPFC) plays a crucial role in Multiterminal-High Voltage Direct Current (MT-HVDC) systems for balancing the DC power flows in transmission lines. Conventional methodologies generally rely on single-stage topologies for IDCPFC, but their applicability to high voltage contexts is constrained by limitations in device ratings and susceptibility to electromagnetic interference (EMI). In interconnected networks with varying lengths of transmission lines, each line exhibits unique resistance levels, complicating the efficient achievement of voltage specifications. This paper presents to introduce a new high-voltage multi-terminal modular solid-state transformer (SST) based IDCPFC topology. The objective of this proposed topology is to expand the voltage range of IDCPFC to enhance power flow control within the MT-HVDC network. In order to minimize the switching losses of the proposed topology and validate its bidirectional feasibility, various modulation schemes are adopted. A thorough comparison of losses between conventional bidirectional topologies and the proposed topology is presented to demonstrate its effectiveness. The proposed control method is simulated on four cascaded modules based on case study of three nodes 500 MW system. The simulated results are further validated through experimental setup with two cascaded modules of 600 W. • This paper introduces a high-voltage multi-terminal modular solid-state transformer (SST) based IDCPFC topology, aimed at expanding the voltage range to enhance power flow control within the MT-HVDC network. • Various modulation schemes are proposed to minimize the switching losses of the topology while maintaining its bidirectional feasibility. • A thorough comparison of losses between conventional bidirectional topologies and the proposed topology is presented to demonstrate its effectiveness. • The proposed control method is simulated on a four-module, three-node 500MW system and validated through an experimental setup with two 600W cascaded modules. [ABSTRACT FROM AUTHOR]

• Typhoon characteristics considering microtopography are discussed. • A detailed FEM of the ETTLS is developed in ABAQUS and experimentally validated. • The influences of microtopography on the typhoon-induced responses of the ETTLS are investigated. • A failure analysis of the ETTLS due to typhoon, taking into account the microtopography, is conducted. Safety of electricity transmission tower-line systems is always at risk from various natural hazards, especially typhoons, which have the potential to cause significant damage and disruption. However, previous studies have predominantly focused on typhoons occurring in open-flat terrains, disregarding the impact of actual terrains. To address this research gap, this paper comprehensively examines the typhoon-induced responses of an electricity transmission tower-line system while considering the influence of microtopography. Specifically, a virtual wind tunnel is first established to simulate the typhoon within a specific microtopography. The wind characteristics of the typhoon considering the influence of microtopography are then studied in terms of the average wind speed, gust factor, and turbulence intensity, and compared to those at open-flat terrains. Finally, the influences of microtopography on the typhoon-induced responses and collapse of the electricity transmission tower-line system are investigated. The results demonstrate that the introduction of microtopography can obviously increase local wind speed and enhance fluctuation of wind, resulting in large responses and collapse risk of electricity transmission tower-line systems. This paper could provide a valuable reference for assessing the wind-resistant capacity of electricity transmission lines located in complex terrains, e.g., mountains and valleys. [ABSTRACT FROM AUTHOR]

The Optimal Power Shutoff (OPS) problem is an optimization problem that makes power line de-energization decisions in order to reduce the risk of igniting a wildfire, while minimizing the load shed of customers. This problem, with DC linear power flow equations, has been used in many studies in recent years. However, using linear approximations for power flow when making decisions on the network topology is known to cause challenges with AC feasibility of the resulting network, as studied in the related contexts of optimal transmission switching or grid restoration planning. This paper explores the accuracy of the DC OPS formulation and the ability to recover an AC-feasible power flow solution after de-energization decisions are made. We also extend the OPS problem to include variants with the AC, Second-Order-Cone, and Network-Flow power flow equations, and compare them to the DC approximation with respect to solution quality and time. The results highlight that the DC approximation overestimates the amount of load that can be served, leading to poor de-energization decisions. The AC and SOC-based formulations are better, but prohibitively slow to solve for even modestly sized networks thus demonstrating the need for new solution methods with better trade-offs between computational time and solution quality. • This paper considers a planning problem for optimizating Public Safety Power Shutoffs. • The problem is modeled with 4 power flow formulationsm: AC, DC, SOC, and NF. • These formulations demonstrate a tradeoff between solution quality (accurate estimates of load shed) and solution speed (orders of magnitude difference). • The formulations are made available in the open-source software package PowerModelsWildfire.jl. [ABSTRACT FROM AUTHOR]

• This paper presents a new modeling for analyzing transient grounding system behavior during a direct lightning strike. • The modeling that we propose makes it possible to treat even a complex grounding circuit like that encountered in wind farms where we have several interconnected groundings. • This modeling developed directly in the time domain considers the effect of frequency and ground ionization. • The modeling that we propose uses the transmission line equations with frequency dependence, the vector fitting technique and the Finite Difference Time Domain numerical method. • The modeling that we propose makes it possible to overcome the numerical disadvantages that may be encountered when implementing a full-wave electromagnetic formalism when the structure studied has large geometric dimensions, inhomogeneous and has open boundaries. This paper presents a new model for analyzing transient grounding system behavior during a direct lightning strike. The modeling that we propose allows us to consider a simple grounding conductor buried horizontally or vertically, a grounding grid, wind turbine grounding system and grounding circuits for wind farms while including the aerial parts (towers and blades). This modeling is developed directly in the time domain taking into account the frequency dependence of the impedance and admittance of the wired conductors and of the electrical parameters of the soil (ρ, ε) and also considering the ionization of the soil. This formalism is based on transmission line equations, rational approximation by vector fitting and the Finite Difference Time Domain numerical method. The proposed formalism is verified considering both simulations and experimental results from available published researches. The Ground Potential Rise GPR in the grounding circuits of wind farms are discussed during the first stroke and also during the subsequent stroke whose frequency range generates more propagation of electrical waves along conductors. This formalism makes it possible to contribute to all knowledge/research of grounding systems. [ABSTRACT FROM AUTHOR]

• Data on the corona characteristics of AC conductors (LGJ-300/40) during rainfall were obtained from tests in an artificial climate chamber. • It was found that the AC corona characteristics of conductors were mainly affected by the rainfall intensity rather than the rain conductivity. • Rainfall has a greater effect on the corona characteristics of conductors compared to dry conditions, but moderate rain is recommended as a reference for corona design of transmission lines. • Raindrops cause distortions in the electric field strength in the vicinity of the conductor, leading to vibration and rupture of the raindrops, and the critical rupture electric field decreases as the radius of the raindrops increases. How to reduce the effect of rainfall on the corona discharge of conductors is a problem that must be considered in the design and operation of transmission lines. This paper takes LGJ-300/40 conductor as the sample, and experimentally investigates the influence of rain conductivity and rainfall intensity on the corona characteristics of AC conductor in multi-functional artificial climate chamber, and analyzes the surface electric field strength distribution of rain-drenched conductor and the vibration and rupture of raindrops. The results show that changing the rain conductivity does not affect the corona characteristics of AC conductor. Compared with the dry environment, the corona inception voltage decreases by 36.94 %∼45.16 % with the increase of the rainfall intensity (from drizzle to rainstorm), and the corona loss and the audible noise increase. The corona loss and the applied voltage satisfy the power function for different rain conductivities (or rainfall intensities), the corona characteristics of the conductor change less in moderate rain and above. The critical rupture electric field strength of water droplets decreases with the increase of raindrop radius. The results of this paper have some reference significance for the selection and design of AC transmission lines. [ABSTRACT FROM AUTHOR]

• The influence of meteorological factors on the icing of transmission lines was analyzed in experimental studies. • The proposed Gray Correlation Pearson Combined Analysis (GPCA) combines two types of traditional methods for more effective data analysis. • The GPCA-SVM model established by Gaussian kernel is more effective than the ordinary model under the consideration of data balance. • In this paper, the objective law between multi-dimensional meteorological factors and icing degree is explored, which lays the foundation for the intelligent monitoring system of power grid and provides guarantee for the operation and maintenance of power system. In recent years, ice and snow disasters have occurred frequently, and transmission line icing can pose a great threat to the operation of the power system. In order to solve this problem, the power industry should introduce an intelligent monitoring system to recognize the risk of ice-covered disasters in advance and take timely countermeasures to reduce the impact of extreme weather on the safe operation of the power system. In this paper, we first use Python to sort out and summarize multidimensional meteorological data from multiple locations in the Northeast China, and propose a method called Grey Relational Pearson Combination Analysis (GPCA). Through this method, we determine the correlation between multidimensional meteorological data and icing degree, and select the optimal combination of icing factors as the feature vector for a support vector machine. In addition, we also compare the differences in classification effects of four types of kernel functions, such as linear kernel, polynomial kernel and Gaussian kernel. Finally, considering data balance, we use Gaussian kernel to establish GPCA-SVM model and conduct experimental analysis. There was a 1.04% increase in accuracy, a 1.36% increase in recall, and 0.31% increase in F1 value when comparing gray correlation accuracy and a 21.66% increase in precision when comparing Pearson accuracy at light icing. Comparison of gray correlation accuracy at heavy icing improved by 1.04%, precision by 17.44%, and F1 value by 10.29%; comparison of Pearson accuracy improved by 0.31%, precision by 9.93%, and F1 value by 1.67%. These research results lay the foundation for the intelligent monitoring system of power grid, and provide guarantee for the operation and maintenance of power system. [ABSTRACT FROM AUTHOR]

• At present, there is no systematic analysis of the causes of overheating in the research on connection fittings for extra-high voltage direct current transmission lines both domestically and internationally. Only through simulation of overheating defects, the impact of overheating on transmission lines has been studied, and no systematic investigation plan for related defect problems has been proposed. • The model proposed in this paper can be used for analyzing problems related to ±800 kV extra-high voltage DC overhead transmission lines, as well as for ultra-high voltage DC overhead transmission lines such as ±500 kV, and has strong universality. • This paper propose a systesmatic troubleshooting plan for related defect issues, which has important reference and guidance significance for such line fault problems. This paper studies the overheating defect of an extension rod in a ± 800 kV extra-high voltage direct current overhead transmission line, and proposes various factors that affect the overheating of the extension rod. Establish an equivalent model of an extra high voltage DC transmission line based on equipotential point and line parameter analysis, and calculate the model parameters. The proposed model can also be applied to ultra-high voltage DC overhead transmission lines such as ± 500 kV, and has strong universality. Simulation experiments show that if the equivalent resistance value of the split wire side is reduced by 0.01Ω, the power loss on the extension tie rod can be increased to 380.951 W; if the equivalent resistance value of the jumper side is increased by 0.01Ω, the power loss on the extension tie rod can be increased to 273.41 W. Combined with theoretical analysis and simulation verification, it is concluded that the main factor affecting the overheating of the extension rod is the change in the resistance value on the jumper side caused by the increase in contact resistance. A systematic troubleshooting plan for related defect problems is proposed, which has important reference and guidance significance for such line fault problems. [ABSTRACT FROM AUTHOR]

• The proposed single-ended fault location framework fully considers the effect of partial coupling, without requiring measurements from the remote ends. • Within the proposed framework, two methods based on impedance line model and fully distributed line model are presented. • The effectiveness of the proposed methods is validated through many simulation analyses. The proposed methods demonstrate some robustness towards measurement noises and parameter errors. Accurate fault location technology can not only speed up fault search but also enhance the power supply reliability. This paper introduces a single-ended fault location framework for single line to ground faults, taking into account the effects of partially coupled lines. The proposed framework relies only on local measurements. Within the proposed framework, the two methods proposed in this paper are based on the impedance line model and the fully distributed parameter line model, respectively. The impedance model based fault location method does not require iteration and has no risk of divergence, while the method based on the fully distributed parameter model has higher accuracy. The estimated results of the impedance-based method can be used as the initial values of the solution of the distributed parameter model based method. The proposed methods are validated through a number of testing cases, encompassing various fault locations, resistances, and coupling ratios. [ABSTRACT FROM AUTHOR]

• Proposes an improved YOLOv5s model which combines the GIoU, Mish, and CBAM modules. • The improved algorithm can effectively detect different-size insulator defects under different environmental backgrounds. • The AP value in detecting insulator defects can be improved by 5 %. As one of the most important components on the transmission line, the insulator is prone to failure, which affects the safe operation of electrical power system. Hence, it is crucial to accurately detect the insulator defects for further maintenance in time. Recently, with the development of artificial intelligence and target detection algorithms, the insulator defect detection has received more and more attention. However, there are still existing some difficulties: insufficient samples and low detection accuracy. To improve the accuracy of insulator defect detection, this paper proposes an auto-detection method based on an improved lightweight YOLOv5s model. First, this paper introduces the basic network frame of YOLOv5s and proposes an improved algorithm by utilizing the GIoU loss function, Mish activation function, and CBAM module. Then, performs data enhancement in the insulator dataset to enhance the robustness of the model. Finally, trains and tests the improved YOLOv5s model, and compares it with traditional target detection algorithms. Compared with traditional target detection algorithms, the AP value of the proposed algorithm in detecting insulator defects can be improved by 5 %. The results demonstrate the improved algorithm proposed in this paper can effectively identify and position the insulator defects. [ABSTRACT FROM AUTHOR]

• The feasibility of the ICOG corona ring is verified by simulation analysis. • The opening distance, installation orientation and insulating layer thickness of the opening corona ring are simulated and analyzed, and the parameters of the ICOG corona ring are determined. • The electric field of the ICOG corona ring in the case of bird droppings is simulated and analyzed. • Through the bird droppings simulation test, the anti-bird performance of the ICOG corona ring is verified. In the bird-related faults of transmission lines, the bird droppings flashover fault caused by the short-circuiting of bird droppings to the corona ring is extremely significant. To decrease the flashover probability of bird droppings and improve the convenience of installation, this paper proposes a method of coating the insulating layer on the open-gap corona ring, and verifies the insulation performance of the insulation coated open-gap (ICOG) corona ring through simulation and experiment. In this paper, the feasibility of corona ring coating insulating layer is verified by finite element simulation, and the influence of ICOG corona ring structure on the surface electric field distribution of composite insulator is studied. Finally, the impact of various bird droppings parameters on the flashover of the ICOG corona ring is investigated through experiments and compared with the flashover of an ordinary corona ring. The simulation results show that when the opening distance is 50–70 mm, the opening is toward the tower side, and the thickness of the insulating layer is 5 mm, the surface field strength of the composite insulator is the smallest. The experimental results show that the flashover probability of bird droppings increases with the increase of conductivity and viscosity of bird droppings. After the open-gap corona ring is coated with the insulating layer, the area where the bird droppings flashover occurs is reduced by about 20 %, which can better play the role of anti-bird flashover and has better convenience. This paper provides a certain reference for the anti-bird control of transmission lines. [ABSTRACT FROM AUTHOR]

Extreme events such as floods, hurricanes, earthquakes, and wildfires pose significant threats to the uninterrupted supply of electricity to consumers, as they can cause the failure of numerous power system components. The resilience of a power system is defined by its ability to withstand extreme events and continue meeting demand. While the placement of multi-carrier microgrids (MGs) in power systems can impact resilience, the literature lacks research on resilience-oriented placement. This paper aims to address this gap by proposing a resilience-oriented placement strategy for multi-carrier MGs, utilizing switchable transmission lines to enhance the resilience of power systems. The study focuses on a heat-power-hydrogen MG that obtains gas from a gas network, exchanges power with the main power system, and incorporates combined heat and power (CHP), electrolyzer, and thermal storage. The developed model employs a stochastic mixed-integer linear programming (MILP) approach, ensuring the attainment of the global optimum. Resilience is evaluated using the metric of expected load not supplied (ELNS). The results demonstrate that when the bus connected to the MG is isolated, the MG generates electricity through its CHP unit to meet local demand, reducing the total demand shed in the power system and improving system resilience. Specifically, the MG reduces ELNS from 4955.48 MWh to 2356.64 MWh, indicating a remarkable 52% improvement in ELNS. Furthermore, the study shows that transmission line switching further decreases ELNS from 2356.64 MWh to 848.68 MWh. Several experiments are conducted to analyze the sensitivity of power system resilience to the number of MGs, the MG-power system exchange limit, and the limit on gas import from the gas network. • Heat-power-hydrogen microgrids (MG's) are used to improve power system resilience. • Resilience-oriented optimal placement of MGs has been done. • Transmission line switching is used to improve the resilience of power systems. • The effect of the number of MGs on power system resilience is assessed. • Sensitivity of system resilience to MG-power system exchange limit is assessed. [ABSTRACT FROM AUTHOR]

With the large-scale integration of renewable energy and changes in load characteristics, the power system is facing challenges of volatility and instability. Therefore, enhancing the safe and stable operation capability of the power system is an urgent problem that needs to be solved. Mobile energy storage can improve system flexibility, stability, and regional connectivity, and has the potential to serve as a supplement or even substitute for fixed energy storage in the future. However, there are few studies that comprehensively evaluate the operational performance and economy of fixed and mobile energy storage systems. To comprehensively evaluate the economic benefits of large-scale mobile energy storage systems, this paper constructs an overall horizontal cost model for energy storage systems that considers the power system and train transportation system. This model not only introduces the traditional concept of lifecycle cost of energy storage systems, but also considers the costs of traditional transmission lines and battery transportation. Secondly, to achieve simulation of large-scale mobile energy storage system planning and operation, this paper establishes a multi-region power planning and operation simulation (MPO) model and a battery transportation and logistics (BTL) model to accurately reflect the operation mode of fixed energy storage and mobile energy storage in the power system. Finally, taking the actual power grids and railway networks in Northeast and North China as case studies, this article provides an in-depth analysis of the technical, economic, and environmental performance of large fixed and mobile energy storage systems, and conducts a detailed comparison. The research results indicate that under high grid connection ratios (using 75% and 66% as examples), the overall cost of mobile energy storage systems continues to decrease to 1.42 CNY/kWh and 0.98 CNY/kWh. Compared to fixed energy storage at 5.45 CNY/kWh and 4.79 CNY/kWh, it has an absolute economic advantage and shows significant carbon reduction capabilities, reaching 241,800 to 1,394,600 tons. This discovery fully confirms the enormous potential and application value of mobile energy storage in high proportion renewable energy scenarios, providing strong technical support and economic analysis basis for the sustainable development of the power system. • The overall levelized cost model of large-scale mobile energy storage system is established. • Tech-economic performance of fixed and mobile energy storage system is compared. • The proposed method can improve system economics and renewable shares. [ABSTRACT FROM AUTHOR]

• EMTP-based results clarify that SPCB operation results in WF voltage swell. • The results show that the CSC and DSC controllers with the FRT, are not effective. • To improve the HVRT after the SPCB operation, a dc-link chopper is provided. For transient single phase-to-ground (SPG) faults in transmission lines, single-pole circuit breaker (SPCB) operation can improve system reliability. This issue is more critical in transmission lines emanating from wind farms (WFs). In the large-scale WFs, the grid codes necessitate that wind generation remains in operation during the transmission line faults. For this purpose, the grid codes focus on the development of fault-ride-through (FRT) requirements. In this paper, it is shown that after the SPCB operation, the terminal voltage of the permanent magnet synchronous generator (PMSG)-based wind turbine (WT) rapidly increases and may cross the high-voltage ride-through (HVRT) boundary. Therefore, the WT terminal overvoltage after the SPCB operation may result in undesirable tripping of the WT. The obtained results in this paper show that in most cases both the coupled and decoupled sequence controllers of the WT converter equipped with the FRT requirements are not able to improve the HVRT performance after the SPCB operation. To enhance the HVRT performance of PMSG-based wind turbines after the SPCB operation, a dc-link chopper controller is proposed. EMTP-RV simulation results on the IEEE 118-bus and 5-bus systems show the success and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

• Emphasizing load modeling's critical role in TRV calculation, particularly in substations with short lines. • Discussing load modeling's influence on CB selection, a factor ovelooked in current standards. • Investigating the distinct effects of active and passive loads on TRV calculation in real sub-transmission systems. • Providing a comprehensive system modeling for TRV analysis, incorporating finite element models to compute stray capacitances. In this paper, the selection of circuit breakers for a densely-meshed sub-transmission system with relatively short transmission lines is investigated. The results highlight the significance of modeling the load at the end of lines for accurately calculating the transient recovery voltage (TRV) following the short-circuit current interruption. According to IEEE standards, assuming load modeling at the end of the transmission lines can result in a maximum discrepancy of 20 % in the calculated TRV. Supposing that the load modeling leads to a moderating effect on the calculated TRV, the difference is considered as a safety margin, and load modeling is ignored. Nevertheless, the results presented here illustrate that this assumption strongly depends on characteristics of the studied network and the load type. In a network possessing the characteristics outlined in this paper, even a passive load as small as 15 % of the nominal capacity can significantly moderate the calculated TRV, with impacts reaching up to 38 %. Conversely, modeling an active load may result in a more severe TRV than if it were disregarded. The simulation results indicate that for networks with transmission lines longer than 70 km, neglecting to model passive loads on the transmission lines still yields sufficiently accurate calculations of TRV. [ABSTRACT FROM AUTHOR]

This paper presents a new, improved approach to fault location in long and very long transmission lines, which uses measurements at both terminals of the line that do not need to be synchronized, using the satellite time-reference. The new method employs symmetrical component sequence voltage profiles that are computed using an innovative approach in which the detailed three-phase model of a multiconductor transmission line is represented as the series connection of several chain matrices. This allows the new method achieve the best performance, when compared to other 4 similar fault location approaches, requiring measurements at both terminals of a symmetrical line, considering all types of faults, under realistic variations in variables and parameters of the test system, including the effect of saturation of current transformers, and arc faults. The main advantage of this proposed technique is that it can be applied with no major changes in symmetrical and unsymmetrical transmission lines keeping its good performance. In addition, division of the line in chain matrices allows the new proposed approach to be applied in non-homogeneous lines. In this paper, for space reasons, the new approach is initially applied to symmetrical (ideally transposed) transmission lines only, with very successful and encouraging results. • This approach considers the detailed model of a multiconductor symmetrical line. • It achieves the best performance of all the considered algorithms of this type. • It was tested successfully considering 15 different realistic conditions. • Measurements do not have to be synchronized. • The simplicity of the algorithm, make it adequate to be implemented in a relay. [ABSTRACT FROM AUTHOR]

• Protection for inverter-based resources (IBRs) based systems has many challenges. • Developed superimposed quantity-based protection elements for a system with IBRs. • Protection elements are tested in a modified IEEE 9-bus system. • Evaluated system resilience with various maximum current limits in PV controllers. The increasing penetration of inverter-based resources (IBRs) to the power grid brings challenges to protection systems. IBRs may not provide sufficient fault current to trip protective relays, leading to delays in fault isolation and increased risk of equipment damage. To overcome the challenges, superimposed quantity-based elements are developed in this paper for transmission line protection in a power grid with IBRs. The characteristics of the designed protection system are tested under fault conditions in a modified IEEE 9-bus system that includes solar photovoltaic (PV) generation, and evaluated with different maximum current limits in solar PV controllers. The applied method in this paper makes contribution to the protection application for IBR-penetrated transmission systems. Simulation results show that the modeled protection system works effectively with different penetration of solar PV, and the system resilience is enhanced under fault conditions considering the tripping response and reclosing of circuit breakers. [ABSTRACT FROM AUTHOR]

This paper introduces a fault location method based on time analysis, utilizing synchronized data collected from both ends of the faulted line. The data is obtained either from Common Format for Transient Data Exchange (COMTRADE) files or Sampled Measured Value (SMV) of the IEC-61850 protocol. The method proposed in this study employs the implicit finite difference solution to the Telegrapher's equations. In certain fault scenarios, such as when one or both transformers experience saturation, a narrow time window of data can be utilized to accurately pinpoint the fault location. The implicit solution method is unconditionally stable and therefore decouples the choice of the line discretization step from the sampling time interval, which is commonly required to maintain numerical stability of the explicit strategies for fault location. Furthermore, the numerical stability of the implicit process allows for devising a systematic search procedure that improves the accuracy of the calculated fault location, regardless of the transmission line length. By conducting numerical comparisons with an explicit time-domain fault locator and recent frequency-domain algorithms, the superiority of the proposed approach becomes evident. The results highlight the significant improvements achieved through the utilization of this method. Specifically, the results demonstrate that Telegrapher's Equations implicit finite difference solution maintains accuracy under current transformer saturation, as it can locate the fault using data from a brief interval where the current transformer is not saturated. • In this paper, an implicit PDE solver for two-ended fault locations is proposed. • The proposed strategy improves the solution process's numerical stability. • It maintains the best numerical conditioning by using integration steps that produce the least amount of calculation error. • The method outperforms the previous published method. • The method can be applied in cases where CTs are saturated, and when there is only a limited window of "healthy" data available. [ABSTRACT FROM AUTHOR]

• Calculation of reactor and grid coefficients for magnetically coupled series reactor design. • Considering calculated coefficient to design series reactor out of saturation region. • Presenting saturation issue as a main challenge of the series reactors. The rapid increase of integrated distributed generators results in higher fault currents in the future modern grids. A remedy for the concern is employing series reactors as fault current limiters. This paper elaborates on a ferromagnetic core series reactor, which, when saturated, adversely affects the operation of the series reactor during faults. The main goal of the paper is to calculate grid and series reactor coefficients by applying a simplified power line model during a fault condition. These coefficients are the primary considerations of a series reactor design to avoid its saturation. Moreover, the study of the relationship between the reactor inductance and obtained coefficients will be carried out. The obtained results are validated by simulations performed in MATLAB Simulink. [ABSTRACT FROM AUTHOR]

• A novel mobile robot is designed to remove debris from high-voltage power lines. • A novel mobile robot that can be integrated with a drone for transportation. • A mobile robot was developed and tested in high-voltage power lines up to 138 kV. The importance of electrical energy in human life has grown considerably, resulting in a great surge in demand for this energy form. As a consequence, numerous power transmission lines are continuously under construction. Periodic inspections and maintenance of equipment and accessories associated with these lines are crucial to ensuring their proper functioning. Thus, this paper introduces a novel mobile robot designed to remove debris from high-voltage power lines up to 138 kV. This robot offers several advantages, including reduced costs related to maintenance operations that require specialized human labor, increased task efficiency, and reduced risks to human physical integrity by eliminating the need for manual tasks in direct contact with high-voltage lines. This paper outlines the development and validation of a novel robot that can be integrated with a drone for transportation, bringing an innovation to the format for carrying out maintenance in the electric power distribution system. After reviewing robots applied to debris removal, our study presents the novel robot's design and control system. The robot was developed and tested in both simulated and real environments, proving to be efficient and cost-effective in improving debris removal from high-voltage lines while ensuring linemen's safety. [ABSTRACT FROM AUTHOR]

• This paper proposes a fault location method based on directional traveling wave principle for wind power transmission line. • The similarity of forward current traveling wave and reverse current traveling wave at both ends of line is higher after external fault, while similarity of forward current traveling wave and reverse current traveling wave at both ends of line is lower after internal fault. • Discrete Frechet distance is utilized to calculate similarity coefficient of forward traveling wave and reverse traveling wave at both ends of transmission line. The short-circuit current from the new energy power generator presents special characteristics such as frequency shift, restricted amplitude, unequal positive and negative sequence impedance, high percentage of harmonic content, etc., resulting in the risk of misoperation or rejection of conventional protection. By analyzing the propagation characteristics of traveling wave in the transmission line after the fault, this paper reveals difference between traveling wave waveforms at both ends of the line under internal fault and external fault. The similarity between forward traveling wave and reverse traveling wave at both ends of line is higher when an external fault occurs, while the similarity between the forward traveling wave and reverse traveling wave is lower after internal fault. According to this difference, a pilot protection algorithm based on discrete Frechet distance is proposed, which can calculate similarity coefficient of forward traveling wave and reverse traveling wave at both ends of line to construct protection criteria, and then identify internal and external fault. Through the analysis of PSCAD/EMTDC and experiment platform of hardware-in-the-loop test verify that the proposed protection algorithm can accurately and reliably distinguish internal and external fault. [ABSTRACT FROM AUTHOR]

Electroencephalography (EEG) is commonly used for measuring brain activity information due to its high temporal resolution. However, it severely suffers from noises produced by non-brain sources, called EEG artifacts. Ocular, muscle, and power line artifacts are the most common ones. In this paper, a novel two-stage automatic artifact removal method is proposed to handle different artifacts under miscellaneous EEG applications. Empirical wavelet transform (EWT), canonical correlation analysis (CCA), and an outlier detection algorithm, isolation forest constitute the pipeline. In the first stage, EEG data are decomposed by CCA and preliminary purified by isolation forest. In the second stage, a further decomposition of the EEG data is conducted using EWT and CCA, followed by removal of irrelevant components using isolation forest. We thoroughly evaluate the qualitative and quantitative performance of the proposed method on multiple datasets. Experiment results show that the proposed method can effectively remove artifacts under complex conditions and different signal-to-noise ratios. Ablation studies and comparison results demonstrate the significance of the two-stage combination, which outperforms single-stage methods and state-of-the-art methods. This paper explores the potential for a fully data-driven and adaptive way for robust artifact removal in various EEG applications. • We combined empirical wavelet transform (EWT) with canonical correlation analysis and isolation forest. • We designed a two-stage removal process which focused on different artifacts at different stages. • We tested our method on multiple datasets, in a variety of ways. [ABSTRACT FROM AUTHOR]

• A method to correlate indirect lightning strokes and flashovers is presented. • The method focuses on the ratio between current peak and distance from the line. • The results provided by Rusck's and Darveniza's formulas and LIOV code are compared. • The minimum collecting area for calculating the lightning performance is addressed. Lightning location systems provide an estimation of both lightning current peak amplitudes and stroke locations, which are useful information to correlate lightning strokes and faults in power distribution networks. The paper presents a novel method for assessing the correlation between a lightning-induced flashover and the lightning current-peak-to-distance ratio of indirect lightning events. This is motivated by the consideration that a minimum threshold/value of the ratio between current peak and stroke distance from the line must be reached for an insulation flashover to occur. The proposed procedure uses existing equations and models that relate induced voltage peak amplitudes, distance, current peak and other parameters. Specifically, the paper compares the results predicted by Rusck's and Darveniza's formulas with those provided by the more detailed model implemented in the LIOV code. It is found that a minimum lightning current-peak-to-distance ratio must be exceeded to trigger an insulation flashover and that Rusck's and Darveniza's formulas may be too conservative in estimating such a threshold value. The paper provides guidelines for properly estimating the minimum collecting area around the line including all hazardous events, as this information is essential for calculating the lightning performance of a power distribution line using a Monte Carlo-based approach. [ABSTRACT FROM AUTHOR]

• This research paper proposed a novel computational technique for evaluation of the corona generated ionized electromagnetic field environment which initiates serious ill health environment under EHV/UHV DC transmission lines. • The proposed new computational technique was developed by modelling the dynamic behavior of the corona discharge phenomenon using gas ion bimolecular collision theoy concept which offers program less simple equations. • This developed computational technique offers unique equation solution which estimates corona generated ionic currents for any existing and upcoming HVDC transmission lines. This new computational analysis offers economical benefits to the line design engineers. • Actual experimental investigations are carried out at extra and ultra high potential levels to validate the accuracy of the proposed computational technique. • The proposed computational technique offered high computational accuracy compared to other techniques which are proposed elsewhere in the world and the computed results shown exact measured values. Corona on UHVDC transmission line conductors initiates corona power loss and the inevitable ionic current flow environment at ground level. To limit this substantial flow of ionic current at ground levels, it is necessary to establish an appropriate line design configuration, including the diameter of the line conductor and the height level above the ground. It is a tedious and expensive process to establish this appropriate line design solely based on experimental findings. Hence, the computational based numerical analysis with the support of final experimental validation aids in arriving at a safe and optimal transmission line design dimension configuration. Thus, the ionic current flow environment of UHVDC transmission lines may be characterized by ionized space charge density, ionic current flow, and electrical field distribution. To estimate this ionic current flow, it is necessary to estimate the ionized space charge density in the ionization region, which incorporates the solution of the Poisson's equation. It is intricate to solve Poisson's equation with known boundary conditions: as ionization process depends on the atmospheric parameters also. Multiple computational techniques are developed to estimate the corona generated ionic current environment under the HVDC lines by waiving these atmospheric parameter effects and claims the lack of computational accuracy. In this paper, the unipolar corona equation, usually called Poisson's equation was solved by estimating the space charge ion density using the concept of gas bimolecular collision theory. The gas bimolecular collision theory inculcates the procedure to estimate the collisional reaction rate constant between the gas molecules at given atmospheric temperature and pressure parameters. Therefore, this paper developed a unique equation solution for the estimation of transition of the ionic current magnitudes at known atmospheric temperature and pressure ambient conditions. This unique equation solution prevents the multiple actual testing procedures offers to obtain safe and optimal line design dimension configurations. Multiple experimental studies are carried out up to ± 900 kV to compare the computed results in the outdoor and indoor climatic conditions at the ultra-high voltage laboratory, CPRI. Also, the computed results are compared with the results published in the literature. Based on the comparison of results, the developed computational technique exactly matches the experimental results and claims improved accuracy compared to other computational techniques. [ABSTRACT FROM AUTHOR]

In the past few years, analog computing has experienced rapid development but mostly for a single function. Motivated by parallel space-time computing and miniaturization, we show that reconfigurable graphene-based multilayers offer a promising path towards spatiotemporal computing with integrated functionalities by properly engineering both spatial- and temporal-frequency responses. This paper employs a tunable graphene-based multilayer to enable analog signal and image processing in both space and time by tuning the external bias. In the first part of the paper, we propose a switchable analog computing paradigm in which the proposed multilayer can switch among defined performances by selecting a proper external voltage for graphene monolayers. Spatial isotropic differentiation and edge detection in the spatial channel and first-order temporal differentiation and multilayer-based phaser with linear group-delay response in the temporal channel are demonstrated. In the second section of the paper, simultaneous and parallel spatiotemporal analog computing is demonstrated. The proposed multilayer processor has almost no static power consumption due to its floating-gate configuration. The spatial- and temporal-frequency transfer functions (TFs) are engineered using a transmission line (TL) model, and the obtained results are validated with full-wave simulations. Our proposal will enable real-time parallel spatiotemporal analog signal and image processing. [Display omitted] [ABSTRACT FROM AUTHOR]

Concerned with deploying zero-emission energy sources, reducing energy wasted through transmission lines, and managing power supply and demand, monitoring and controlling microgrids have found utter importance. Accordingly, this paper aims to investigate the efficacy of state estimation fusion for a synchronous generator as well as an induction motor in order to ameliorate system monitoring. A third-order nonlinear state-space model, that operates based on actual input data taken from the Smart Microgrid Laboratory, is assumed for each of the electrical machines. The model parameters are set according to the parameters of the electrical machines. A fusion structure based on the internet of things communication network, which is modified to increase uncertainty, is presented for fusing the state estimates. The data fusion topology is distributed and relies on two data fusion models. The first model is a set of state estimators, referred to as data input-feature output model. The second one fuses the estimators' outputs based on supervised machine learning methods, referred to as feature input-feature output model. The simulation results in MATLAB and Python show the efficiency of linear regression methods compared with other leveraged methods for data fusion. By comparing the results obtained from both simple and complex estimation filters, it can be deduced that combining simple filters, extended Kalman filter in this case, with simple data fusion methods, linear regression in this case, can produce much more accurate results in a short period of time. Besides, this study shows that the averaging operators are unsuitable for estimation fusion by referring to their convexity condition. • Regression methods can outperform other methods for the purpose of data fusion. • Simple filters combined with simple fusion methods boost state estimation accuracy. • The averaging operators are unsuitable for estimation fusion due to performing convex fusion. [ABSTRACT FROM AUTHOR]

The world's key renewable power markets are generally challenged by wind and solar power curtailment. Research on the influencing factors of curtailment improvement can provide a reference for the further penetration of renewable energy (RE) into the power system. Based on the logarithmic mean Divisia index (LMDI) method, this paper analyzes the factors influencing the wind and solar power consumption rate in China from 2015 to 2018, and four typical provinces are discussed in detail. By decomposing the consumption rate into six factors (transmission structure, generation proportion, power self-sufficiency, resource development, resource utilization, and power consumption), and focusing on the transmission structure factors, this paper further clarifies the contributions of local use, ultra-high-voltage (UHV) transmission, and conventional transmission to the improvement of curtailment. The results reveal the following. (1) At the national level, the power mixing effect and the resource development effect have played major roles in the change of the consumption rate, but the influences of these two effects have been decreasing. (2) The UHV power lines provide a robust resource for the inter-provincial deployment of renewable power (such as the RE power transfer in Inner Mongolia and Gansu), but the role of UHV transmission has not yet been fully utilized. (3) The impact of the electricity consumption effect on renewable power consumption is increasing year by year, but the local consumption capacity remains insufficient (both at the national level and in the four typical provinces analyzed), so it is necessary to further increase the share of renewable electricity in UHV power transmission and the local consumption capacity. (4) The expanding development of wind and solar power may be the reason for the curtailment in Shaanxi, and a reasonable renewable power development plan must be further formulated. [ABSTRACT FROM AUTHOR]

In this paper, different optimization algorithms are introduced to solve the security-constrained optimal power flow between two connected regions, applying two control modes, namely the centralized and decentralized modes. Traditionally, the decentralized control, i.e., each power system controls its variables regardless of the boundary buses, is the most commonly used approach. However, the centralized control has been recently utilized to enhance the system security, because the active power of the generation units and/or the voltage buses on the boundaries are the two variables, which can mitigate the changes, when compared to the decentralized control solution. The optimization techniques applied propose using the Genetic Algorithm (GA) as a tool to validate the solution reached through the Whale Optimization Algorithm. The proposed methodology is investigated on the IEEE 48-bus electric power system, which consists of two regions connected to each other through three transmission lines. The problem can be solved by applying both the AC and DC Optimal Power Flow respectively, using three approaches, namely: 1- Changing the active power of generation unit; 2- Controlling the voltage magnitude and 3- Combining the changes in the real power of generation units and the voltage variations. All the proposed approaches are implemented taking into consideration the technical constraints. All of these different techniques are constructed and modeled by utilizing the Matlab code. The results of each case study are presented; and a final comparison between all the methods utilized is drawn to demonstrate the advantages of each method. The novelty of this paper is represented in investigating the effectiveness of applying the AC Optimal Power Flow and the DC Power Flow, utilizing meta-heuristic techniques. [ABSTRACT FROM AUTHOR]

Wind farm is the cheapest renewable energy resource (RER) in the world, however, the reliability improvement is a key for the future of this power plant. A specially issue is the overhead line interconnection, a weak point, even, a double circuit, the last projects have included modern equipment to mitigate the failure impact in the system as phasor measurement unit (PMU) and Intelligent Electronics Devices (IED); for the dynamic response and protection system. In this paper, a comprehensive dynamic model for the analysis in a Peruvian power plant, located in the north of Perú, with the most recent model based fault analysis and fault tolerant, focusing on overhead lines maximum disconnection time for RER technology interconnection. The remainder of this paper is organized in a tutorial manner with a Matlab code and DigSilent simulation, it allows the same results from the stability study, however faster than traditional methodology and with high accuracy. [ABSTRACT FROM AUTHOR]

• AC induced voltage on the pipelines that neighboring the HVOHTLs is introduced. • In earth faults conditions both of inductive and conductive couplings are studied. • The current of the coating discharging and AC corrosion are investigated. • Influence of using KOH-PCs is studied in the normal and earth fault conditions of HVTLs. Buried metallic pipelines are used to transmit the natural gas and petroleum products to the citizens. Sometimes these pipelines are constructed in the same pathway of the overhead transmission lines (OHTLs) to save the additional right-of-way cost, and to avoid the destruction of agricultural lands. AC voltage is induced on these pipelines by the power lines electric and magnetic fields. There are many mechanisms that describe the AC voltage inducing on these pipelines; capacitive coupling describes the pipelines induced voltage by the power lines electric field, inductive coupling characterizes the induced voltage caused by the OHTLs electromagnetic fields and conductive coupling is created in buried pipelines near to OHTLs by earth fault current. In the present paper the induced voltages of pipelines created by OHTLs due to the different couplings are investigated in normal condition of operation as well as line to ground fault. The current of the coating discharging and AC corrosion are investigated. The induced overvoltage appears on the natural gas pipeline is measured in steady state condition of the transmission circuits operation. Moreover, this paper represents the mitigation of the induced voltages by using two different KOH-PCs systems. [ABSTRACT FROM AUTHOR]

• This article realizes the simultaneous output of high-voltage high-frequency excitation for transmission line measurement. • The proposed differential linear cascaded amplifier topology breaks through the limitation of gain bandwidth product. • Designing appropriate isolation voltage for cascaded power supply can meet different testing voltage requirements. • The parallel fiber optic isolation cascade method breaks through the kHz limitation of high-voltage amplifiers. In this paper, a high-frequency and high-voltage linear cascaded amplifier based on parallel optical fiber isolation is proposed. The electro-optical synchronous drive of the excitation signal is realized through equal proportional laser splitting, which achieves the same linear gain and output phase shift in each photoelectric conversion unit. The differential linear cascade topology designed in this paper effectively solves the gain bandwidth product limitation and achieves a high-voltage linear output in a high-frequency range. The new amplifier solves the problem that due to the low AC excitation voltage of traditional impedance analyzer, the signal attenuation is severe in long distance and high insulation distributed electrical parameter network. It can be widely used to measure high-frequency dielectric loss and impedance spectrum for dielectric materials and electrical components in industry and laboratory. By cascading n -stage amplifier units, the voltage gain can reach 6n times. Finally, a 16-stage cascade amplifier is built, and the response characteristics are tested with the distributed electrical parameter network loads. The output characteristics show that the expected amplifier gain can be obtained accurately in the high-frequency range of 100 kHz–100 MHz, the output voltage can reach 192Vpp, and the peak current can reach ±500 mA. The maximum of the curve about THD and noise versus frequency could be limited to 0.49 %, which could meet the needs of on-site measurement. [ABSTRACT FROM AUTHOR]

• This paper proposes a novel fast time-domain protection scheme in a large-scale PPP system, with prominent features such as simplicity. • There is no need of parameters tuning because of the adaptive nature of ITD. Also, all the protection scheme parameters are determined analytically, such as threshold value and number of iterations. • A wide variety of fault scenarios are analyzed for fault detection such as different fault resistance, location and types. • Communication medium is not required. Consequently, there is no communication delay and data loss. • The protection scheme's capability in various conditions such as noisy environments, uncertainty in renewable energy generation, change in GC, various sampling frequencies and CT saturation is discussed. • The proposed protection scheme is tested in two the 2-bus and IEEE 39-bus test systems in MATLAB and PSCAD environments. The performance of a distance relay can be significantly affected by various uncontrolled factors such as fault resistance, fault type, fault location and noise. Moreover, when photovoltaic power plants are integrated into electrical grids, they exhibit distinct fault current characteristics compared to conventional power systems with synchronous generators. These factors introduce variations in the recorded apparent impedance, deviating from the predefined settings of the distance relay. This paper presents an effective scheme for fault detection using ITD methodology. The ITD method decomposes the target signal into proper rotation and monotonic signals, which are then used to calculate the Energy Index. The performance of this scheme has been extensively investigated under various scenarios, including fault resistance, fault location, fault type, CT saturation, GC compliance, noise, and sampling frequency. To validate the effectiveness of the proposed scheme, simulations are conducted using both the PSCAD/EMTDC and MATLAB software. The proposed scheme is assessed using both the 2-bus and IEEE 39-bus test systems. The results show the merit and effectiveness of the proposed scheme in the accurate diagnosis of fault detection with 400 Ω fault resistance, in the presence of 20 dB noise, with variable sampling frequency (0.5-16 kHz) and variable irradiance values (600-1000 (W / m 2)) in power systems. [ABSTRACT FROM AUTHOR]

• The experiment observed, recorded and analyzed the natural icing process of insulators, but most of the previous studies were simulated in the laboratory. • This paper analyzed the icing process of different types of insulators (shed structure, Shed diameter) under natural icing environment. • The influence of wind speed, humidity, precipitation and temperature on the natural icing process were analyzed. • Based on the final icing morphology under natural condition, this paper took the of icicle number, icicle length, icicle diameter, icing thickness of shed surface and icing mass as characteristics, analyzed the differences in icing results of different structures insulators, and got the conclusion (4), which provides reference for insulator selection of transmission lines in icing areas. Icing flashover of insulator strings has always been a serious factor threatening the safety and stability of the power grid. Researchers have simulated icing based on an artificial climate chamber, but it cannot fully simulate the growth process of insulator strings during the icing period in the natural environment. The icing growth characteristics of insulator strings in the natural environment are not clear. In this paper, three kinds of porcelain insulators were tested in the Xuefeng Mountain natural icing test base of Chongqing University. The results show that the freezing rain, alternating icing of freezing rain and freezing fog can cause the insulator stings to form glaze and mixed rime, and the icing degree on the windward side is more serious than leeward side. The higher the test environment's precipitation, humidity and wind speed, the faster the insulator strings' icing speed. And there are also some influences of the ambient temperature on the icing morphology in this test. The icing thickness on the windward side of the insulator shed will gradually increase. The number of icicles of insulators is positively correlated with the diameter of insulator sheds. The icing mass of insulator strings is seriously affected by their shed structure. [ABSTRACT FROM AUTHOR]

• Blackouts bring major economic and societal repercussions. • Efficient black-start strategy is critical to address increasing risk of blackouts. • Variable speed hydro can provide a fast response and is used during black start. • Meet black start needs with renewables and cutting diesel use. • RES-BESS boosts power and fortifies an integrated renewable grid. A blackout refers to a total power outage that rapidly plunges the electrical power system into a severe crisis, posing significant challenges for subsequent restoration efforts. Blackouts can occur due to a range of factors, such as delays in clearing faults, generator malfunctions, equipment failures, and human errors. After a blackout occurs, all possible measures are taken to achieve the fastest power system restoration. To ensure preparedness for such emergencies, scheduled black start exercises are conducted using units capable of initiating power restoration from scratch, allowing authorities to assess their readiness in catastrophic scenarios. Numerous similar exercises have been conducted regularly generating to highlight the complexities of power system restoration of the grid with the black starts of hydro generating units. This has aided plant operators in improving restoration methods and finding additional remedial steps to enhance existing processes to achieve an effective black start exercise. This paper overviews the multiple mock black start exercises applied to hydroelectric generating units and discusses several blackouts worldwide. In addition, Tehri Hydro Power Plant is considered for the case study. Tehri HPP is linked to the 400 kV EHV grid, which was later upgraded to 765 kV transmission lines. Further, this paper observes and discusses various challenges encountered during mock black start exercises. Possible remedial actions are suggested to address these challenges. [Display omitted] [ABSTRACT FROM AUTHOR]

• Proposed a protection scheme can determine the fault type only by calculating the similarity of one-mode current. • Based on the principle of one-mode current similarity, offering a viable solution to address the challenges arising from weak-infeed, frequency offset, and phase uncertainty caused by the LVRT strategy of the new energy station. • Proposed a protection scheme has good adaptability when the wind farm operates independently, and can also adapt to different wind farm capacity and energy storage ratio, which has certain application prospects in practical engineering. With the gradual growth of the scale of energy storage devices for wind power generation, a large-scale grid-connected wind-storage combined system (WSCS) has been formed. When the external transmission line fails, its control strategy will lead to problems such as limited output short-circuit current amplitude, frequency deviation from power frequency, and uncertain phase angle, which makes the traditional pilot protection possible to malfunction and refuse to operate. In order to solve this problem, this paper first analyzes the fault current output characteristics of the WSCS during low voltage ride through (LVRT), and its impact on the traditional pilot protection scheme. Secondly, considering the difference of fault current amplitude and phase change at both sides of the transmission line, the similarity relationship of one-mode current is verified. Finally, a pilot protection scheme based on one-mode current similarity is proposed in this paper. The simulation results conducted using PSCAD/EMTDC demonstrate that the proposed scheme exhibits robust anti-interference capability, capable of withstanding significant transitional resistance and noise, while maintaining good selectivity and reliability. [ABSTRACT FROM AUTHOR]

The huge differences in the visual shapes of multi-angle shooting objects leads to the poor performance of deep neural network (DNN). In this paper, an object detection model named TRUST-TECH-based visual clustering network (TTVCNet) for power line inspection is constructed. First, a TRUST-TECH-based visual clustering method (TTVCM) for multi-view-shape unsupervised clustering is proposed and can learn the difference in visual shape according to the object's views, which is the core of TTVCNet. Then, a Cascaded R–CNN object detection model based on TTVCNet is constructed for the power line inspection. Moreover, we apply the bilinear interpolation method and feature enhancement fusion techniques to this object detection model to solve the problem of small sample detection and semantic loss. In this paper, TTVCNet is applied to the MS-COCO 2017 dataset, and the test accuracy is improved up to 65.3%, especially the recognition accuracy of multi-view-shape is greatly improved. In the contrast experiment of self-made power line inspection dataset, the recognition accuracy of TTVCNet has been greatly improved, and the overall recognition accuracy is 86.3%. [ABSTRACT FROM AUTHOR]

This paper analyzes the impact of water and emission limitations on expansion planning of thermal power plants (TPPs), in Iran. TPPs need considerable amount of water for their cooling system. In Iran, water crisis of recent years has made it impossible to operate existing steam power plants in some areas, during summer season. This paper considers water availability and cost in generation expansion planning (GEP) of Iran. There are different types of water resources such as rivers, dams, treated wastewater, seawater, seawater transmission line, saline groundwater, and groundwater. Considering available capacity of water resources in each area and sorting their extraction cost in ascending order, some water consumption cost curves are derived. For this purpose, data of about 200 water resources located in different regions of Iran are analyzed. Provided GEP model includes a 15-years planning horizon and analyzes several scenarios of water availability. Although, in low water price scenarios, air temperature and height above sea level have more impact on placement of TPPs, it is different for high water price scenarios. Also, the effect of emission-related policies on GEP decisions is analyzed by considering various fuel types of TPPs, penalties for emissions, and global restrictions on greenhouse gas production. • Proposes an optimization model for generation expansion planning (GEP) that considers environmental constraints. • Analyzes the availability and price of different water resources in Iran and their effects on GEP decisions. • Examines the impact of temperature and height above sea level, on the siting of thermal power plants in Iran. • Considers decarbonization policies in the expansion planning of power plants in Iran. [ABSTRACT FROM AUTHOR]

• This paper proposes a fault location method based on composite traveling wave, which can easily eliminate the traveling wave from adjacent lines. • The traveling wave from other adjacent lines, which is never detailed discussed in previous research, hinders the accurate identification of wavefront. • The refraction coefficient of busbar with multiple transmission lines is negative for current traveling wave, but positive for reflection coefficient. • The time–frequency matrix is able to present the energy of traveling wave in wideband. As the speedy expansion of power gird, the traveling wave fault locator in substation may not always connect to newly added transmission lines in time, which reduces the effectiveness of fault locator. In this paper, an adjacent fault-free line based fault location scheme for newly additional line is proposed. Since the traveling wave from adjacent fault-free line results in severe difficulty for identification of traveling waves from faulty line, the time–frequency matrix is performed to screen traveling waves. Firstly, in order to remove the influence of waves from remote terminals of adjacent fault-free line, the current refraction coefficient is theoretically analyzed. Due to the negative refraction coefficient, traveling waves from remote terminals of adjacent fault-free line can be reduced by the proposed composite traveling wave. Secondly, the time–frequency matrices of composite traveling wave and original traveling wave is obtained by S-transform. Then, these matrices are applied to form ratio matrix which thoroughly eliminated waves from remote terminals of fault-free lines. Moreover, the robustness of the proposed fault location scheme is thoroughly validated by the simulation of PSCAD/EMTDC. Finally, the proposed fault location method has the great accuracy in simulation tests and field data test. [ABSTRACT FROM AUTHOR]

Despite advancements in technology, power system faults leading to electric power interruption remain a significant issue. Efficient restoration of the power system relies on the swift classification and clearance of faults. Among the various types of faults in transmission lines, open circuit and short circuit faults are commonly encountered. This study specifically focuses on the analysis of five types of short circuit faults: line-to-line, line-to-ground, double line-to-ground, triple line, and triple line-to-ground faults. Faults can cause both power failure and power loss in transmission lines. Once a fault occurs, it is crucial to restore electricity supply promptly to prevent further losses. Therefore, the development of a system capable of accurately and swiftly detecting and removing faults is essential. Traditionally, categorizing transmission line faults required sophisticated mathematical modeling, intricate signal processing techniques, and expert knowledge to interpret the output signals. In this paper, an alternative approach is proposed, utilizing deep learning techniques for transmission line fault classification. Specifically, the paper employs techniques such as artificial neural network (ANN), long short-term memory (LSTM), with and without window regression (WR). By implementing these deep learning techniques, automatic feature extraction and signal processing are achieved, streamlining the fault classification process. The experimental results obtained from this study demonstrate an accuracy of 42.98% for ANN, 99.98% for LSTM, and 99.99% for LSTM-WR. These outcomes underscore the effectiveness of the deep learning techniques employed in accurately classifying transmission line faults, with LSTM and LSTM-WR outperforming ANN in terms of accuracy. [ABSTRACT FROM AUTHOR]