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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 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]

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]

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]

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]

• 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]

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]

• 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 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]

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]

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]

• 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]

• 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]

Mixed-size cell circuits dominate in advanced technology node designs, with attendant increases in layout complexity. The introduction of multi-row-height cells requires additional constraints, such as power line alignment, to be considered in the legalization stage, in addition to eliminating overlap while maintaining the results of the global placement stage as much as possible. In this paper, a three-stage legalization methodology is presented. The first is cell preprocessing, namely cell diffusion based on the network flow algorithm. Then the legalization problem is modeled as a quadratic programming problem, which is converted into a linear complementarity problem and solved by an accelerated modulus-based matrix splitting iteration method. Finally, the illegal cells are reshaped. Experimental results reveal that our method achieves 11.8% and 0.4% reduction in total displacement, respectively, over existing two state-of-the-art works, and is 1.407x faster than the modulus-based matrix splitting iteration method. In particular, the proposed approach provides a reference for solving large-scale quadratic programming problems. • We develop an efficient mixed-size standard cell legalizer that requires less cell total displacement. • We propose a fast iterative method for the linear complementarity problem with positive semidefinite matrix. • We use a shaping-like methodology that avoids excessive displacement of the cells in the post-processing stage. [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]

Typhoon poses a significant challenge to the reliable and safe operation of power grids. A novel priority-load based preventive scheduling method that considers conventional generators and wind power is proposed to fully exploit the potential of wind power for resilience enhancement. First, the wind speed variation rule in different positions of the typhoon wind speed field is studied according to the characteristics of typhoon. Second, considering the influence of strong wind on the failure rates of transmission lines and tie-lines connecting the power sources and the main grid, the vulnerability curve is used to establish the fault model of lines during typhoon disasters. Third, the utility function of typhoon disaster is represented by the S-type curve, and satisfaction for typhoon resistance (SFTR) index is defined as the objective of coordinated scheduling model. The results show that SFTR can be increased by a factor of 27.9% by exploiting the wind power potential. Compared with the load shedding based method, the priority-load based method proposed in this paper can improve SFTR by 47.6% at most from the perspective of improving the capacity of satisfying important loads to enhance system resilience. [ABSTRACT FROM AUTHOR]

Nowadays, the local distribution grids have been facing technical, economic, and regulatory challenges, because of the increased integration of renewable energy sources (RESs) and electrification of vehicles. The traditional solutions to the grid expansion, e.g., to build an additional power line, are utility-centered solutions, i.e., the distribution grid operators (DSOs) are the only party involved to tackle grid issues. The DSOs have to engage grid users with technology providers to develop innovative solutions that tackle one problem and overcome several cost-effectively. This paper presents a holistic solution to optimally control cross-sectoral energy flow between interconnected microgrids (MGs) consisting of different RESs, hydroelectric power plant (HPP) and wind turbines (WTs) to meet electric vehicles (EVs), residential, commercial and industrial demands with the main grid contribution. This issue will provide the advantages of community-based MGs for local energy trading which causes for an active and engaged system, however, an adequate control strategy for proper operation is required. The proposed solution is based on a new interconnection line between two MGs through a multiport converter (MPC) with the techno-economic consideration of newly installed components such as MPC, cables and the required battery energy storage system (BESS). The proposed case study is evaluated under three different conditions e.g., load increment, demand response (DR) and N-1 criterion in separate, interconnect and island modes. The CPLEX solver of GAMS software is employed to solve the mixed-integer linear programming model. The results show that the applied interconnection line for MGs compared to the separated operation mode can decrease the system's total costs, reduce the applied peak to the upstream grid, and enhance the system's reliability under different conditions. Furthermore, the applied solution provides the ability for MGs operation even in island mode under different conditions for a full day (24 h). • Minimizing OPEX and CAPEX costs under load variations, N-1 criterion, and DR. • Optimal BESS sizing for separate, interconnect and island conditions in MGs. • Optimal MV cables cross-section size for new interconnection line between MGs. • MPC Sizing for more functionality to Host EVs and BESS in interconnected MGs. [ABSTRACT FROM AUTHOR]

This paper addresses the crucial task of power line detection and localization in electrical infrastructure inspection using Unmanned Aerial Vehicles (UAVs) from weak supervision, polyline annotations. We first identify several limitations in the state-of-the-art approach LSNet. In particular, the inability of LSNet to detect line-crossings and lines in close proximity. To overcome these limitations, we propose LSNetv2, which enhances LSNet with multi-line segment detection capability facilitated via a bipartite matching loss. Additionally, we update LSNet's regression loss in order to stabilize training by reducing the interdependence between predicted coordinates. Finally, LSNetv2 makes use of an increased receptive field to extract global information, improving overall detection performance. Through extensive evaluations on various power line detection datasets, LSNetv2 demonstrates superior performance and robustness. On the public datasets PLDU, PLDM and TTPLA, it achieved F β scores of 0.857, 0.875, and 0.671, respectively, while using only modified weak polyline annotation, establishing itself as an effective and efficient solution for power line detection in UAV-based electrical infrastructure inspections. • Visual power line detector using (weak) polyline annotation. • Bipartite matching loss facilitates accurate detection of overlapping lines. • Improved feature extractor and regression loss compared to predecessor LSNet. • Empirical evaluation demonstrates LSNetv2's benefits. [ABSTRACT FROM AUTHOR]

Transmission line parameter identification plays a crucial role in power systems. However, existing methods for identifying transmission line parameters face several challenges: (1) when dealing with non-Euclidean data such as power grid data, a considerable amount of noise is introduced, (2) inability to treat the power grid as a global system, limiting calculations to individual transmission lines and overlooking inter-branch correlations, (3) high sensitivity to data contamination. To address these issues, this paper proposes a multi-task noisy graph attention network (MNGAN) for power grid parameter identification, which leverages the spatial structure of the power grid and considers the inter-branch correlations. By computing the homogeneity and average degree of the graph data, we introduce an adaptive attention mechanism to the model. This attention mechanism dynamically adjusts the model's focus on key information, mitigating the impact of data contamination and improving parameter identification accuracy. Additionally, to achieve simultaneous recognition of multiple branch parameters and enhance model training speed and accuracy, we incorporate a multi-task loss function based on homoscedastic uncertainty. Experimental results demonstrate the superiority of our proposed model over other machine learning and deep learning methods, providing more accurate predictions of branch parameters. [ABSTRACT FROM AUTHOR]

• The proposed ACLC fully utilizing the electrical quantities of the line to identify the fault area has achieved the selectivity of ACLC, preventing ACLC from expanding the scope of fault impact. • The proposed ACLC start-up threshold and control parameters are independent of the simulation. • The proposed ACLC presents a phased approach that satisfies both speed and selectivity. • The proposed ACLC can effectively limit the fault current and has certain adaptability to the fault type, fault resistance, and noise. The modular multilevel converters (MMC) based high-voltage direct-current (HVDC) grids have a fast rise rate and higher peak value of fault current. The active current limiting control (ACLC) of MMC can effectively reduce the breaking current of DC circuit breakers (DCCB) and reduce the requirement for rapid fault identification in the line protection. However, the current ACLC based on changing the MMC control strategy cannot meet the selectivity requirements. The lack of selectivity may lead to power transmission on non-faulty lines in a multi-terminal DC power grid, thus expanding the range of fault influence. Therefore, this paper proposed a selective and staged ACLC. Firstly, the starting range of ACLC is determined according to the selective requirement and purpose of ACLC in the flexible DC power grid. Secondly, a staged ACLC approach was proposed to balance the speed and selectivity of ACLC. In this approach, the single end and both terminals electrical quantities of the line are fully utilized as the starting criteria for staged ACLC, and corresponding ACLC principles are proposed. Finally, the AC side current and MMC bridge arm current under ACLC were analyzed, and an ACLC scheme was proposed in coordination with DC circuit breakers (DCCB) and fault identification. The simulation results show that the proposed ACLC guarantees the current limiting ability and the MMC does not block during the whole fault period, and has a certain adaptability to the fault type, fault resistance, and noise. [ABSTRACT FROM AUTHOR]

• For the time-domain distance protection, its location error caused by the fault resistance is derived. • An improved time-domain distance relay is proposed to solve the calculation non-convergence and improve the location accuracy. • A threshold selection method is proposed to avoid the possible overreach problem under external resistive faults. • A prototype protection device is developed, and its feasibility and superiority are verified by hardware-in-the-loop tests. Time-domain distance protection has a good transient performance and operation speed when applied to wind power transmission lines. In this paper, the error analysis and improved method of phase-to-phase time-domain distance protection are investigated. Firstly, based on the time-domain mathematical model, the location error caused by fault resistance is analyzed, and then the algorithmic convergence and accuracy of conventional phase-to-phase distance relay are evaluated. To solve the computational non-convergence problem, an improved phase-to-phase distance relay is proposed, in which the instantaneous negative-sequence current is used to improve the location accuracy, especially during the fault transient stage of wind farms. In order to avoid the protection overreach problem, the threshold selection method is designed based on the maximum allowable error of the calculated distance. According to the proposed method, the corresponding protection device is developed. And the hardware-in-the-loop (HIL) test system is built based on the real-time digital simulation (RTDS) platform. Extensive experimental tests are carried out, to verify the feasibility and superiority of the proposed time-domain distance protection. [ABSTRACT FROM AUTHOR]

The decreasing cost of energy storage technologies and the increasing utilization of renewable energy sources have made distributed transmission-scale energy storage economically viable. Merchant energy storage investors can collect significant profits through spatiotemporal energy arbitrage from congested transmission lines. This paper formulates a three-stage, four-level min–min–max–min problem from the viewpoint of power system operators and planners such that they will build new transmission lines and identify potential locations for profitable merchant energy storage investments. The first level determines transmission expansion decisions from the system operator's perspective. The second level plans potential investments in merchant energy storage to ensure profitability at a desired rate of return. The third level realizes the worst-case situations of long-term uncertainties related to the expansion of wind farms and peak load growth in each regional zone, while the fourth level simulates market clearing for representative days, modeling short-term uncertainties. A novel iterative nested column and constraint generation (C&CG) technique is adopted to cope with numerical issues caused by binary variables of transmission lines and storage blocks and the enormous size of the problem. The case study of a modified IEEE 24-bus test system was used to assess the effectiveness of the proposed algorithm. • Proposing a new robust co-planning of transmission expansion and profit-driven merchant energy storage. • Considering short-term variability and long-term uncertainty of wind farm expansion and future load growth. • Adopting a novel iterative nested column and constraint generation (C&CG) technique to solve the four-level problem. • Validating the effectiveness of the proposed method and sensitivity analysis in 24-bus IEEE test system. [ABSTRACT FROM AUTHOR]

The proliferation of converter-interfaced generation necessitates the investigation of novel small-signal multi-machine interactions. The flexibility and lack of standardisation of converter control approaches results in a plethora of potential implementations, bringing different dynamics that can interact with each other and existing elements of the power system. This paper performs a small-signal analysis of power systems with the inclusion of grid-forming and grid-following converters for varying combinations of common control architectures, in terms of cascaded control loops, within the literature. Investigations are performed for a two-machine system and the WSCC 9-bus (three-machine) system. As well as interaction identification and characterisation, the impact of varying transmission line lengths, system loading, and generation dispatch are investigated. • Small-signal multi-machine interaction identification and analysis. • Comparison of different grid-following and grid-forming cascaded controllers. • Impact of system parameter variations. • Results highly depend on specific system layout, operating point, and controllers. [ABSTRACT FROM AUTHOR]

Electric demand and renewable power are highly variable, and the solution of a planning model relies on capturing this variability. This paper proposes a hybrid multi-area method that effectively captures both the intraday and interday chronology of real data considering extreme values, using a limited number of representative days, and time points within each day. An optimization-based representative extraction method is proposed to improve intraday chronology capturing. It ensures higher precision in preserving data chronology and extreme values than hierarchical clustering methods. The proposed method is based on a piecewise linear demand and supply representation, which reduces approximation errors compared to the traditional piecewise constant formulation. Additionally, sequentially linked day blocks with identical representatives, created through a mapping process, are employed for interday chronology capturing. To evaluate the efficiency of the proposed method, a comprehensive expansion co-planning model is developed, including transmission lines, energy storage systems, and wind farms. • Transmission and generation expansion problems are often based on time series. • Time series aggregation methods are used to reduce computational complexity. • We propose to use representative days with adaptively selected representative hours. • The efficiency is improved by using a piecewise linear dispatch representation. • Long-duration energy storages are modeled by tracking the daily state of charge. [ABSTRACT FROM AUTHOR]

The key of traveling wave (TW) fault location (FL) method is the calculation of TW velocity and the calibration of TW wave head. In order to achieve high-precision FL, detailed transmission line (TL) parameters are needed to accurately calculate the TW velocity. In view of the problem that the existing high-precision TWFL methods are highly dependent on the calculation of TW velocity, the paper contributes to following aspects: (i) the mapping relationship between wavefront frequency and fault distance/fault pole is constructed; (ii) a neural network model suitable for FL and fault pole identification is designed, which is optimized by Particle Swarm Optimization (PSO) algorithm and Levenberg–Marquardt (L-M) algorithm; (iii) a complete FL scheme is proposed. In order to verify the FL accuracy of proposed method, an ± 800 kV bipolar high-voltage direct-current (HVDC) transmission system model is constructed using PSCAD/EMTDC. According to the simulation results, the errors of FL is less than 0.2 km and the accuracy of fault pole identification is 100%. For the problems of fault type, fault resistance and noise, the proposed method shows high robustness. • The relationship between frequency and fault location/fault pole is constructed. • Not depend on transmission line model parameters. • Higher fault location accuracy. • Robust against fault resistance. [ABSTRACT FROM AUTHOR]

Vulnerable transmission lines are one of the weak links in the operation of the power system, as their damage can trigger widespread blackouts and cascading failures. The integration of large-scale wind power generation into the grid has resulted in significant changes to both the topology and distribution patterns of power flows inside the system, exacerbating line vulnerabilities. Identifying these lines can enhance power system safety through vigilant monitoring or augmenting their carrying capacity. In this paper, a method for identifying vulnerable lines based on the theory of topological potential is proposed. The method is based on the N-1 fault model of optimal DC power flow, and a corresponding network is constructed for the power system. The task of pinpointing weak points in a complicated network is converted into an assessment problem of important nodes. The proposed index comprehensively considers the in-degree and out-degree topological potentials of nodes, and uses the entropy weight method for weight allocation. Meanwhile, the TLS distribution is used to fit the wind power prediction error. Finally, simulation experiments are conducted on the IEEE 39-bus system. Simulation results indicate that the most vulnerable transmission lines tend to be located at the hubs of the system's topological network and in close proximity to wind farms. • The proposed method maps the power system into a complex network using an N-1 contingency model. • To better reflect the real situation of the power grid, the method adopts optimal DC load flow dispatch. • To consider the uncertainty of wind power output, the method utilizes TLS distribution to fit the error of wind power output. • Simulation results indicate that lines near wind farms and topological hub structures are often most susceptible to faults. [ABSTRACT FROM AUTHOR]

In recent years, there has been an exploration of innovative electric grid concepts centered around power routers, devices capable of controlling power flows as desired. One of which is the Power Router Grid, a novel high-controllable network design fully based on power routers. Its ability to arbitrarily change power flows inside controllable lines raises the challenge of determining the optimal operation within such systems. This paper aims to push further the analysis of the operation and benefits of such networks by proposing a novel optimization model tailored for power router grids based on the most recent literature for the convexification of optimal power flows. Moreover, it demonstrated that radial-based models can be expanded for grids meshed through power routers. The model presented is also convex in the form of a second-order cone, ensuring a global optimum for diverse grid configurations. It has been implemented in Python using the PYOMO modeling language and applied to three case studies investigating the effects of power router operation modes on the grid's optimal operation and associated costs. Results show that the definition of the power router grid design and the ports operation mode must be carefully decided when demand uncertainty of over 25% is taken into consideration. Moreover, controlling power flow near lines of higher impedance can lead up to a 21% increase in line losses. • A novel and linearized optimal power flow model for electric grids based on power routers. • Application of second-order cone convexification for grids meshed through power routers. • Analysis of the effects of the layout and power controllability in line losses inside the power router grid. • Implementation of the optimization model in pyomo. [ABSTRACT FROM AUTHOR]

• Inaccuracy of fdLine model in simulating transients in TLs with underbuilt wires assessed. • Higher errors in 100 kHz-1 MHz range, linked to lightning overvoltage wavefronts. • Errors increase with soil resistivity; up to 25 % difference in peak transient voltages. • Prefer ULM over fdLine for transient analysis in TLs with underbuilt wires using EMT programs. This paper investigates the potential inaccuracies associated with using a modal-domain model featuring a real and frequency-independent transformation matrix in simulating electromagnetic transients on power overhead lines equipped with underbuilt wires. Three transmission line configurations are examined: one without underbuilt wires, one with a single underbuilt wire, and another with two underbuilt wires. Comparisons between the simulated voltages computed using the modal-domain approach and a more accurate phase-domain model as a reference reveal that the modal-domain approach leads to inaccuracies in the simulated voltages. These inaccuracies intensify with an increase in the number of underbuilt wires and the soil resistivity. Differences of up to approximately 24 % in the peak values of the simulated voltages were observed, considering the transmission line geometry analyzed in this study. Based on these findings, it is recommended that for simulating transients in overhead lines with installed underbuilt wires, phase-domain models, such as the Universal Line Model, should be employed. [ABSTRACT FROM AUTHOR]

This paper leverages the shape of current traveling waves to enhance transmission line protection. It investigates the distortion effect on the traveling waveshape during propagation along the transmission line. It focuses on utilizing the ratio of area to the peak of the initial traveling wave at the local end to estimate the level of distortion and identify faults within the protection zone. This eliminates the need for arrival time information of initial waves, detection of subsequent traveling waves, and synchronized data communication from the remote end. Effectiveness of the proposed method is evaluated through simulations of faults in a 400 kV transmission network and real-time testing on the RTDS Novacor simulator. The ratio of area and peak, being less affected by the fault resistance and variation in inception angle, the proposed method offers more reliability for traveling wave-based line protection compared to available techniques. • Shape of current TWs are analyzed. • Area and peak of the waveshape are utilized for line protection. • Only Initial TWs are utilized and detection of subsequent reflected TWs not required. • Performance is promising for wide variety of faults. [ABSTRACT FROM AUTHOR]

This paper presents a framework for evaluating the wind-induced resistance of overhead transmission lines (OTLs), aiming to overcome the limitations associated with disregarding temperature effects and relying on a single metric for failure assessment. The proposed framework factors in temperature influence, carefully considers applied loads and structural characteristics, and accurately calculates failure probability based on a specific case study. Meteorological data is initially collected to create a probabilistic model of wind speed and temperature distribution, accounting for correlation. Components and systems are graded based on structural characteristics and damage modes. The neural network surrogate model is trained with finite element computations for load-structural response sample sets. The surrogate model, in conjunction with logistic regression, generates samples to determine fragility. Finally, the total structural failure probability and monthly failure likelihood are computed by integrating the joint probability model and fragility. Analyses highlight temperature's significant impact on conductor-ground line safety, validating the proposed framework's rationale. [Display omitted] • A joint probability distribution model for wind speed and temperature based on measured data is developed. • An OTL performance classification criteria is proposed. • An RBFNN surrogate model is modeled. • Fragility and failure probability of OTL is studied in detail. [ABSTRACT FROM AUTHOR]

This paper presents a novel backup protection scheme integrated with fault location capabilities for unsynchronized three-terminal multisection hybrid untransposed double-circuit transmission lines. The proposed non-iterative scheme fully considers the distributed nature of line parameters along with couplings between phases. Initially, upon activation of this scheme, a new technique for discerning internal faults from external ones and other disturbances is proposed. It effectively overcomes the limitations of existing scheme for faults close to Tee-point (T-point) when terminals are unsynchronized. Subsequently, the faulted branch, section and phases are identified using the developed algorithm. The performance is evaluated for different external and internal intra-circuit and inter-circuit fault cases. Performance comparison is conducted to explore the superiority of the proposed scheme over existing approaches in switch-on-to-fault cases and faults occurring in close proximity to the T-point. Furthermore, the scheme's robustness is assessed under different variations in fault types, fault locations, fault resistances, line parameters, and synchronization angle errors through Simulink/MATLAB simulations. Obtained simulation and experimental results reveal the efficacy of proposed scheme over recently reported schemes. • Backup protection for unsynchronized three-terminal multisection transmission lines. • Utilization of online phasor measurements of voltages and currents for switch-on-to-fault cases. • Reliable detection of faults close to T-point utilizing unsynchronized measurements. • Superior performance compared to prevailing schemes. [ABSTRACT FROM AUTHOR]

• A broken overhead earth wire increases the risk of pole high earth potential rise. • Following a strict design diagram is crucial to achieving safety compliance. • Split factor in high-voltage transmission lines is crucial for safety compliance. An electrical high-voltage power system is essential to support everyday electrical demands. Due to the increase in electrical loads, a more rigid design is required to ensure system compliance with standards and policies. High-voltage safety is the number one priority when it comes to the design, installation, commissioning, and operation of the electrical power system network. Safety compliance is getting more complex due to the joining infrastructure between residential and high-voltage projects. Nowadays, high-voltage infrastructure, including substations and transmission lines, is constructed near residential properties. This neighboring setup increased the safety concerns of high voltage systems, especially under fault or system malfunction situations. Safety concerns are addressed during the design stage and verified during the commissioning stages. The paper discusses the minimum transmission line earthing system requirements. This document provides a clear and consistent approach to assess transmission line earthing system design. The work contents comply with current IEEE standards including rigid author research outcomes. The works reduce the complexity of the assessment and explain the critical role of different sectors within the transmission line network. The work introduces the boundaries when the fault current analysis should include the earth grid resistance. A case study is also included. [ABSTRACT FROM AUTHOR]

Dynamic line rating techniques are increasingly prevalent in the computation of ampacity for overhead transmission lines. Some of these methods, commonly employed by system operators, rely on real-time measurements to calculate conductor temperature, either directly or indirectly. Despite their widespread usage, the susceptibility of these techniques to measurement errors has been largely disregarded in prior research. In this regard, this paper includes a groundbreaking reliability analysis addressing the impact of measurement errors on various dynamic line rating techniques in overhead lines, based on conductor temperature estimation. Two case studies are presented, incorporating typical errors from simulations. The first case study adopts a standard 24-hour profile for the variables involved in the conductor ampacity calculation. In the second study, Monte Carlo simulations are conducted, in which meteorological variables are randomly assigned with five load levels to evaluate the current's influence on measurement noise sensitivity. The resulting ampacity errors across all methods considered are remarkably high, with mean values exceeding 150% in specific scenarios. This unequivocally demonstrates that the commonly accepted levels of measurement accuracy in these widely used rating techniques yield estimations falling far below acceptable reliability standards. • Reliability assessment of DLR methods based on conductor temperature evaluation. • Daily profile for the temporal evolution of estimation errors in estimated DLR. • Monte Carlo simulations for statistical characterization of errors. • Unacceptable errors under typical measurement errors. [ABSTRACT FROM AUTHOR]