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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 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]

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 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]

• 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]

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]

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]

When the substation grounding grid and part of the underground metal pipe grid are close to each other, the two produce resistive coupling, and the current of the transmission line will flow through the grounding body and through the soil to the buried pipe grid, which may break through the anti-corrosion layer of the pipe grid, and may burn the body of the pipe grid in serious cases; the underground metal pipe grid will also have an impact on the parameters of the grounding grid. To this end, this paper is based on the numerical calculation method of field-path coupling, combined with the actual situation of substation, using CDEGS and ETAP software to simulate and analyze the current dissipation process when a short-circuit fault occurs in the substation after the ground grid is put into operation under multi-layer soil environment, and to study the influence of resistive coupling between the grounding grid and the surrounding metal pipe grid during an industrial frequency grounding short circuit. Optimize the structure of the grounding system so that the contact voltage across and step voltage is lower than the safety limit to protect the personal safety in the station; at the same time, take certain protective measures to slow down the corrosion of the pipe grid. [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]

An effective way to promote the consumption of renewable energy resource generation is by forming a joint power supply system between photovoltaic (PV) power plants widely distributed along a river basin and large-scale cascade hydropower plants, using shared transmission lines to transmit power to the power grid system. However, renewable energy resource generation has significant prediction uncertainty and can flood into the power grid, which is detrimental to its safe and stable operation. To solve the above issues, this paper proposes an improved interval optimization method to model the uncertainties of the inflow runoff of a cascade hydropower plant and the photovoltaic power output. On this basis, a medium- and long-term interval optimization scheduling model is established for a cascade hydro-PV complementary system based on extreme scenarios. This model does not need to obtain an accurate probability density distribution for renewable energy, and can realize the overall optimization of runoff-PV uncertainty scenarios within a certain range, taking into account the economy and robustness of system operation. In order to ensure the solution efficiency, the original model is transformed into a mixed integer linear programming (MILP) model by a variety of deterministic transformation methods and linearization techniques. The case study shows that: 1) Under the premise that the system power output is relatively stable, the power curtailment of the interval optimized scheduling scheme proposed in this paper is reduced by 47.5% compared with the robust scheduling scheme. The ability to cope with extreme scenarios is also significantly improved compared with the deterministic scheduling scheme. 2) There is a game relationship between the robustness and economy of the obtained scheduling scheme. When the fluctuation interval width of random variables increases from 20% to 30% and 40%, the corresponding total power generation decreases by 2.4% and 4.7%, respectively. 3) A large penalty factor is conducive to reducing the amount of abandoned hydropower, but in general, the penalty factor and ecological flow level have no obvious influence on the dispatching results, and the values of both can be reasonably determined according to the actual operation requirements. • An improved interval optimization method is proposed to deal with the uncertainty of inflow runoff and PV power output. • A MILP model for the medium- and long-term operation of a cascade hydro-PV complementary system based on extreme scenarios is established. • The resulting scheduling scheme achieves balance between economy and robustness. • The influence of penalty factor and ecological flow on the dispatching results is not obvious. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of how corona losses on transmission lines depend on weather conditions in their vicinity. Two years of synchronized phasor measurement data has been collected to monitor corona losses over a longer period of time. From the same time period, both hourly and 10 min weather monitoring data has been obtained for comparison. The dependence between various weather parameters and corona losses is presented with graphical data analysis. In addition, feature importance methods have been applied to rank the weather parameters and determine which of them have the largest influence on the occurrence of significant corona losses. The results presented in this paper are directly applicable for transmission systems operators for adequate planning of system operation. • Transmission network corona loss monitoring using Phasor Measurement Units. • Analysis of corona loss dependency on various weather parameters. • Ranking of weather parameters based on importance. • Dependency of data availability on corona loss estimation results. [ABSTRACT FROM AUTHOR]

Long-distance power support through High-voltage Direct Current (HVDC) has provided feasible solutions for power dispatch and control problems in multi-area power systems under high share of renewable energy. In this paper, an advanced multi-area intra-day dispatch strategy for power systems with high penetration of renewable energy considering power support capacity is established to increase the accommodation of wind power and enhance the stability of the power system. At first, a novel assessment method of regional active power support capacity is carried out in this paper, which can sufficiently quantify the regional power margin (RPM), the DC dispatchable power (DCDP), and the regional power support distance (RPSD) of a power system. Subsequently, a multi-area intra-day dispatch strategy based on power support capacity analysis is proposed, where constraints on conventional units, wind farms, transmission lines, and RPSD are developed. Finally, to enable the development of the dispatch model, a model predictive control (MPC) scheme is used to update the power support capacity indicators dynamically and improve model reliability. The effectiveness and superiority of the proposed strategy are verified by case studies. Numerical results show a 7.02% cost reduction and overload risk reduction by using the proposed strategy compared to conventional global optimization methods. • A novel assessment method of regional active power support capacity is proposed. • A multi-area dispatch strategy considering power support capacity is established. • A model predictive control scheme updates the power support capacity indicators. • Proposed strategy enhances the power system stability and reduces dispatch costs. [ABSTRACT FROM AUTHOR]

This paper introduces a pilot protection method for two-terminal transmission lines based on the measurement residual of an extended Kalman filter designed to track alternate current signals. Transmission lines that interconnect generation plants to consumers are the primary equipment most susceptible to faults, and failing to isolate them correctly and promptly may lead to system collapse. In this context, the measurement residual allows for rapid fault identification and tripping. In addition, the proposed solution requires computing and communication resources typically available for pilot protection since it uses conventional sampling rates and has a low computational burden. This paper details the theory and application of the extended Kalman filter and the results of the proposed method when tested against different simulation scenarios. These scenarios were built on an extra-high voltage transmission system implemented in ATP/EMTP, varying fault impedance, inception angle, distance, phases involved, and fault type. It also presents a statistical analysis of these scenarios, including channel asymmetry, errors in the current transformers' conversion rate, and noise. Besides, it describes an analysis of the proposed method regarding current transformer saturation, high impedance faults, zero-crossing faults, external breaker opening, and power-swing. Finally, it compares the solution with other algorithms in the literature. The results indicate that the proposed solution is fast, accurate, secure, and dependable. • Transmission lines are susceptible to faults that need fast isolation. • Fast isolation preserves stability, avoids equipment damage, and reduces life risk. • The method is based on the extended Kalman filter; estimates the signals' behavior. • Method tested against simulations from an existing 500 kV system. • Faster than conventional protection algorithms, secure, dependable, and accurate. [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]

Environmental pollution has attracted much attention in recent years. Many protocols have concluded between the major countries emitting these gases to reduce its consequences. Hence, governments and countries have considered various strategies to reduce it. One of the most important of these is the use of clean energies in the format of small networks called microgrids and nanogrids. So, this paper presents the optimal energy planning and management of the proposed test system, including microgrid, nanogrid, and the main grid. The whole grids are connected by transmission lines, enabling them to work in connected or islanding mode. Diverse scenarios are considered to investigate and cover all aspects of this. Thus, at first, the operation of each network is studied separately in the islanding mode, then the behavior of the proposed system in the connected mode is discussed. Moreover, uncertain parameters are involved in the programming to perform stochastic planning. The economic-ecological analysis is assumed as the objective function. The problem is modeled as MILP and solved simultaneously by augmented epsilon constrain (AEC) and LP-metric methods in GAMS software. The results show the effectiveness of the proposed planning to coordinate the function of the micro–nanogrid combination scheme. • Enviro-economic evaluation of the microgrid–nanogrid joint structure. • Investigation of stochastic planning considering uncertain parameters. • Considering AEC and LP metric methods for appraisal of the responses. • Components such as CHP, boiler, MT, WT, and PV are taking part in the management. • Decreasing total cost and pollution by exerting proposed planning. [ABSTRACT FROM AUTHOR]

Overhead lines in the United States are currently designed based on both deterministic and probabilistic loading concepts for ice and wind. These load cases are specified in the National Electrical Safety Code (NESC) (Institute of Electrical and Electronics Engineers, Inc. (IEEE), 2023). The deterministic loads for the continental United States are based on three loading districts: light, medium, and heavy, and the corresponding loads based on the specified weather criteria are to be used with specified structural load factors. In practice, the factored deterministic loads often control the design of a structure compared to the probabilistic loads which apply a load factor of 1.0. Furthermore, the deterministic loads are not associated with a Mean Recurrence Interval (MRI), thereby making the assessment of the reliability index cumbersome for structures controlled by these loads. A method to determine an equivalent MRI for these deterministic loads is presented, which involves associating the factored deterministic loads with a probability of exceedance based on location for ice and wind loads. The method is applied to a 230 kV transmission line including seven structure types and line angles, and for 26 locations across the continental United States, and a comparison of the equivalent MRI based on the deterministic loads is made to the probabilistic loads. Trends are presented which illustrate that the resulting equivalent MRI vary significantly among location and structure types. The findings highlight that different structure types of the same transmission line are associated with a wide range of equivalent MRI. Discussion is provided on the trends observed in case study and the inconsistency in structural reliability that could result from the application of deterministic ice and wind load criteria in NESC Rule 250B. It is not the intent of this paper to state what design MRIs are needed to ensure adequate reliability. The intent of this paper is to determine what range of structural equivalent MRIs overhead lines in the United States are currently designed to withstand. • For transmission line structures designed in the United States, what sort of probabilistic weather conditions are these lines designed to resist? • The structural design for many structure types is controlled by the deterministic load case NESC Rule 250B. Since this load case is deterministic the likelihood of exceeding this load (MRI) is not available. • The proposed method provides a way to determine the equivalent mean recurrence intervals (MRIs) for the deterministic structural load case NESC Rule 250B. • The results show that the equivalent MRIs highly vary based upon location. • The results show that structures with small line angles have lower MRIs and structures with large line angles have higher equivalent MRIs. Tangent structures exhibit a median equivalent MRI of approximately 100-yrs. Deadend structures exhibit a median equivalent MRI of approximately 1000-yrs. [ABSTRACT FROM AUTHOR]

• Matrix aggregation algorithm considering the direction of power flow. • A new comprehensive index with line outage distribution factor & line load rate. • A new quantification index of the power flow transfer impact ratio is proposed. • Accuracy of the obtained key lines of key transmission sections increases by 19.6 % With the increasing complexity of high-proportion new energy connected to power systems, the volatility and uncertainty of the power system increase, resulting in the changing operation status of the system. The original general sections may become key transmission sections. According to the power flow characteristics of power systems, this paper proposes an improved matrix aggregation algorithm to determine the initial transmission sections. On this basis, this paper defines an improved comprehensive index based on line outage distribution factor and line load rate. According to the principle of emphasis on detection in the actual power system operation, weight coefficients are considered for the two parameters to determine the key transmission sections. Finally, the correlation between multiple transmission sections is analyzed by quantifying the impact of the trip off line on the power flow transfer of other lines, and the strong correlation section is obtained. Case studies of the IEEE 39 bus system show the validity and effectiveness of the proposed method in this paper. [ABSTRACT FROM AUTHOR]

• The proposed single-ended method uses the extra information brought by the time interval between the operations of the circuit breakers at two line ends; the proposed method also considers distributed line parameters. Therefore, the proposed method has higher fault location accuracy than the existing method. • The proposed formulation of the fault location problem with distributed parameters is subtly simplified by Taylor expansion, and a non-iterative fault location method is proposed. The risk of unconvergence is systematically avoided and the fault location accuracy is ensured at the same time. • The proposed method does not rely on the assumptions of legacy methods (e.g., the fault current and the terminal current are in the same phase, the system is homogeneous, etc.). The proposed method does not require the parameters of the remote power system. Fast and accurate fault location methods can save costs and ensure power supply reliability. This paper proposes a novel noniterative single-ended phasor domain fault location method with distributed parameter model for AC transmission lines. Due to the limitation of information, the legacy impedance-based single-ended fault location methods usually are based on assumptions on the line or system to obtain more information. The method proposed in this paper takes advantage of the additional information brought by the operation mode of circuit breakers. The proposed method only needs the local measurements and does not need the measurements and the equivalent source parameters of the remote system. The proposed method only uses single-ended data and is not affected by communication and synchronization. The proposed method is noniterative and there is no risk of non-convergence. In addition, the method proposed in this paper does not rely on the assumptions of legacy methods and considers the distributed parameters, avoiding the disadvantages of the legacy methods. The effectiveness of the proposed method is verified through a lot of case studies in PSCAD/EMTDC, with different fault types, fault locations and resistances. © 2017 Elsevier Inc. All rights reserved. [ABSTRACT FROM AUTHOR]

• The flexibility of power planning on external tie lines is greatly enhanced. • The novel flexible load aggregation model improves the accuracy response curve. • Strategies focus on the PFS in NZCPGs rather than the distribution and microgrids. • Offset the actual ETLPF to the largest extent and reduce NZCPGs operating pressure. In a net-zero carbon power grid (NZCPG) with a relatively high proportion of renewable energy sources, significant power fluctuations occur, severely constraining the development of both the NZCPG and the New Urban Power Grid (NUPG). In the NZCPG, the proportion of traditional hydro and thermal power units used to mitigate power fluctuations has decreased. It is necessary to explore the load resources in the NUPG to stabilize the power fluctuation between the NUPG and the NZCPG, and to reduce the operating pressure of the NZCPG. Firstly, this paper proposes a method for developing external tie line schedules based on the load operation band (LOB) to relax the constraints on the schedule for the NZCPG. Secondly, A revised load response aggregation model is proposed to improve the aggregation accuracy under uncertainty factors by online correcting their impact on the load response characteristics. Thirdly, considering the flexible loads in NUPG can only compensate for a part of the power fluctuation, this paper proposes a method to judge the power fluctuation that these loads can offset. Two PFS optimal strategies are proposed among NUPG partitions considering deviation penalty and within each NUPG partition reducing the number of participated load-users. This paper focuses on the PFS in bulk NZCPGs other than in the distribution grids and microgrids. Our work can effectively smooth the power fluctuation within NUPG regulation capability meanwhile reducing the number of participated load-users. Fourthly, a method is proposed to judge the power fluctuation beyond NUPG regulation capacity in NUPG. Using the actual load response capacity, the over-amplitude/time layered smoothing strategy with optimal load is proposed, which can offset the power fluctuation of the bulk NZCPG to the largest extent. Finally, the IEEE-39 system is used to verify the effectiveness of the proposed methods. © 2017 Elsevier Inc. All rights reserved. [ABSTRACT FROM AUTHOR]

This paper describes BC Hydro's current design practice for determining ice and wind loads on overhead transmission lines based on the reliability-based design principles. Following important issues are discussed and clarified: selection of design reliability levels, prevention of cascading failures, determination of IceWind load case, inclusion of IceOnly load case, consideration of un-equal ice and broken wire load cases, consideration of wet snow and galloping. The BC Hydro standard practice has been developed based on the industry's best practice and BC Hydro's own successful experiences in the past. This paper may serve as a good reference for other utilities in designing their transmission lines. • This paper describes BC Hydro's current design practice for determining ice and wind loads on overhead transmission lines based on the reliability-based design principles. • Following important issues are discussed and clarified: selection of design reliability levels, prevention of cascading failures, determination of IceWind load case, inclusion of IceOnly load case, consideration of un-equal ice and broken wire load cases, consideration of wet snow and galloping. • The BC Hydro standard practice has been developed based on the industry's best practice and BC Hydro's own successful experiences in the past. [ABSTRACT FROM AUTHOR]

Pipeline dents are mechanical damage caused by a third party in buried pipelines during construction or maintenance repair. Dents are recognized as a leading cause of pipeline failures for both liquid and gas transmission lines, and their assessment and management are critical to pipeline integrity. To meet the industry need, American Institute of Petroleum (API) in 2020 published a recommended practice (RP) 1183 – Assessment and Management of Pipeline Dents. This API code provides the pipeline industry "standard methods" for evaluating severity and fatigue life of pipeline dents with a single peak. This paper performed an initial verification study of fatigue-based methods prescribed in API RP 1183 for estimating fatigue life of pipeline dents. A brief review was first given to the dent fatigue-based methods, including three dent screening methods for estimating dent fatigue life in Sections 7.4.1, 7.4.2, and 7.4.3 of API 1183 and one dent assessment method for predicting fatigue life in Section 8.3.4. In order to verify these fatigue life prediction methods, a set of "standard examples" of dents provided in Annexes A.1 to A.5 of API RP 1183 were utilized in this study to calculate fatigue life, to determine restraint condition, and to evaluate both screening and assessment methods for single-peak dents. Through detailed calculations and comparisons, this study confirmed some specifications of API RP 1183, but also found some self-inconsistences and errors existing in this new API code. This includes the self-inconsistences between three screening methods and the self-inconsistence between the screening and assessment methods. On this basis, recommendations were made on how the operators should use API RP 1183, and what actions API should take to improve this code. • This paper performed a verification study on the fatigue-based methods in API 1183 for estimation fatigue life of pipeline dents. • The K max -based screening methods and PRCI Level 2 assessment method were confirmed to be consistent with the API 1183 specification in terms of conservatism order. • The SSI-based screening method was found to be the least conservative criterion that is inconsistent with the API 1183 specification. • The restraint parameter equation was found that may determine an incorrect restraint condition of pipeline dents. [ABSTRACT FROM AUTHOR]

This paper examines the lifetimes of alternative system configurations for a wireless sensor network (WSN) in a circular region. The coverage region is divided into hexagonal cells, and the information from each cell is combined and transmitted to the sink or to other cells. Sensors are equipped with directional antennas that improve transmit/receive power efficiency and potentially reduce interference. Simultaneous transmission to multiple cells is permitted, and the power level of different transmissions can be controlled to different levels. Under the assumptions of uniform information density and uniform sensor distribution, we show that for larger systems (with 800 cells or more) lifetime can be prolonged by more than 10 times by introducing a limited number of transmission lines or line sinks to facilitate information transfer to the main sink. Alternatively, introducing up to six secondary sinks can increase the system lifetime by a factor of about 4.5 for the same size region. Our results imply that incorporating line or secondary sinks may provide simple, low-cost solutions for extending system lifetime for larger WSN's. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid system is proposed to predict and classifies the power system transmission line faults. The proposed technique is the consolidation of both the truncated singular value decomposition (TSVD) and Human urbanization algorithm (HUA) based Recurrent Perceptron Neural Network (RPNN), and hence it is named as TSVD-HUARPNN technique. TSVD is matrix decomposition, this technique qualify the outcome it as fast or not. In the proposed work, the qualification of the results from the TSVD is improved by a lemma theorem; it is a proven proposition which is used to obtain a larger and optimal result. For that reason, it is also known as a "helping theorem" or an "auxiliary theorem". Here, it has two modules for power system fault analysis: (i) fault detection, (ii) fault classification. The first process of the proposed system is the generation of the dataset of normal and abnormal conditions of transmission line parameters of power system using TSVD. The extracted dataset is assessed by HUA-based RPNN system to classify the fault analysis that occurs in transmission system. The TSVD-HUARPNN system is used to predict and classify the fault present in the transmission line. The proposed TSVD-HUARPNN system ensures the system with less complexity for the detection and classification of the fault, therefore the accuracy of the system is increased. By then, the proposed model is activated in MATLAB/Simulink, its performance is evaluated with the existing models. The performance with noise at 20 dB of the proposed technique is 99.77%. • Hybrid technique is proposed for predicts, classifies the power system transmission line faults. • The proposed technique is the consolidation of both TSVD and HUA based RPNN. • TSVD prepare dataset based on transmission line parameters normal and abnormal condition. • The extracted dataset is assessed by the HUA based RPNN technique. • The proposed technique guarantees the system with lessens complexity. [ABSTRACT FROM AUTHOR]

This paper proposes a novel two-stage adaptive reclosing mechanism for shunt-compensated extra-high-voltage transmission lines. In the first stage, secondary arc extinction peak-based criterion (SAEPC) is established to monitor the precise instant of secondary arc extinction. The approach depends on the magnitude of the faulty phase voltage and the estimated weighted lower-order harmonics. The harmonics root mean square factor (HRF) is presented in the second stage for fault classification, i.e., temporary or permanent. The proposed scheme not only identifies the quenching instant regardless of fault location, compensation level, and arc extinction speed but also determines the nature of the fault. Simulation studies demonstrate the effectiveness and reliability of the proposed scheme and its ability to mitigate the limitations of existing single-criterion harmonics-based reclosing techniques. [ABSTRACT FROM AUTHOR]

• The impact of distributed capacitance is eliminated due to the capacitance current can be ignored at the low frequency. • The low-frequency components only exist between the BES and the fault point, and will not flow to the opposite grid. • The least square algorithm is employed to solve the overdetermined equations, improving the accuracy of calculation. The fault current of the photovoltaic (PV)/battery energy storage (BES) hybrid power generation system contains harmonic components, which might cause the maloperation of the distance relay. The time-domain distance protection has attracted more attention recently. However, the distributed capacitance of long transmission lines negatively affects the performance of time-domain distance protection, which hinders its application. To solve this problem, this paper proposes an improved time-domain distance protection based on fault active control. By leveraging the fault active control capability of the BES inverter, a specific low-frequency characteristic voltage is modulated through the phase-locked loop (PLL). By injecting the low-frequency characteristic voltage, the influence of line distributed capacitance can be ignored. Thus, the accuracy of time-domain distance protection based on the equivalent R-L model of transmission lines is guaranteed, which is the first advantage of injecting the low-frequency characteristic voltage. The other advantage is the low-frequency components only exist between the BES and the fault point, and will not flow to the grid on the opposite side of the line. The accuracy of time-domain distance protection has been further improved. In Addition, the faulty line's derivative equations for different fault types are deduced based on fault active control. Finally, the least square algorithm is used to calculate fault distance. The proposed scheme's feasibility and effectiveness are verified through simulations in PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

• Dynamic line rating (DLR) allows the full capacity of the lines to be utilized. • We study the effect of emissivity on the DLR rating of transmission line conductors. • We also propose model-based method for measuring the emissivity value. • Experimental results show that aged conductors perform better than new ones. Emissivity and absorptivity are important parameters in overhead power line conductors that depend on the conductor surface condition, so their values change as the conductors age. They have an important effect on their thermal behavior, so it is important to know their value when designing dynamic line rating (DLR) strategies. DLR methods are becoming increasingly important, especially in areas with congested power lines, as they allow the full capacity of the lines to be utilized by dynamically determining their maximum allowable currents without exceeding the safe temperature limits of the conductors, thus ensuring that they operate within safe limits. However, measuring emissivity and absorptivity is non-trivial and requires complex tests that cannot be performed in the field. Using simulations based on a realistic thermoelectric model and experimental tests performed on three types of transmission line conductors in a high-current laboratory, this paper shows the importance and effect of emissivity on conductor temperature. It also presents a method for measuring the emissivity value based on adjusting the emissivity and absorptivity values in the thermoelectric model to match the experimental values. The results presented show that aged conductors allow an increase in the maximum current carrying capacity compared to new conductors in the order of 5–14 %, depending on the conductor type considered and the operating conditions. [ABSTRACT FROM AUTHOR]

Power transmission lines play very important roles in power systems. When a fault occurs, a fast process of identification, localization and isolation of the fault is required. To one of the most popular solutions for fault detection and localization belong the distance relays using the impedance based algorithms. This paper will present a new approach using the modified Takagi-Sugeno-Kang neuro-fuzzy network trained on the signals generated by hardware simulator to estimate the shortage fault locations and fault resistances. The solution will base only on the voltage and current signals measured at the beginning of the lines. To compare the simulation results with the real field relay, the simulated lines' signals are regenerated into a relay tester Omicron CMC-356 to test with a real Siemens 7SA522 relay. The numerical results will show that the proposed neuro-fuzzy network can offer very accurate estimation of fault resistances with the coefficient of determination equal 0.9986 and higher accuracy in fault location comparing with the real 7SA522 relay in both relative mean squared errors and maximum errors. [ABSTRACT FROM AUTHOR]

In overhead power transmission lines, particularly in regions like natural parks where establishing a safe zone is difficult, the adoption of cross-linked polyethylene insulated covered conductors (CCs) helps prevent outages due to vegetation contact. However, these CCs are susceptible to partial discharge (PD) activity, which can degrade insulation and lead to system failures. Detecting and analyzing PD are essential for maintaining power system reliability and safety. A key challenge in PD monitoring is transmitting the large volumes of PD signal data over unreliable 2G networks, as existing compression methods either compromise on data integrity or are ineffective. This paper introduces a novel lossy compression technique utilizing an autoencoder with skip connections and correction data to address this issue. Unlike previous algorithms that struggle with noisy time series data and fail to preserve crucial anomaly information, our method reconstructs the signal without anomalies, which are subsequently restored using correction data. Achieving a compression factor of about 25 (reducing data to 4.1% of its original size), this approach maintains essential PD signal features for analysis. The effectiveness of our method is validated by three classification algorithms, showing promise for future fault detection, diagnosis, and memory space reduction. This innovative compression solution marks a significant advancement in PD data processing, offering a balanced trade-off between compression efficiency and data fidelity, and paving the way for enhanced remote monitoring in power transmission systems. [Display omitted] • New method: 1D ResNet autoencoder + correction data preserves signal anomalies. • Custom loss function to reconstruct anomaly-free signals. • High compression for large signal transmission & storage with PD • Low reconstruction error, similar classification results on reconstructed data • Optimized for single-byte signals, outperforms general scientific data compression. [ABSTRACT FROM AUTHOR]

• A new single-end fault location method is proposed for double-circuit transmission lines. • It does not require knowing the impedance of the remote end source. • Just one formulation is used for all symmetrical and asymmetrical faults, both transposed and untransposed lines. • It is suitable for fault location of double-circuit with non-identical circuits. • It reduces the negative effect of unknown fault impedance. A new fault location method based on single-end measurements is proposed in this paper. The proposed method decomposes the fault location problem into two sub-problems and uses the voltage and current phasors of one of the line ends to solve the sub-problems. In the first iteration, an initial value is assumed for the fault location and then, based on the network equations, the first sub-problem calculates fault characteristics such as its voltage, current, and impedance which are fed into the second sub-problem as its inputs. Then, the second sub-problem updates the estimated fault location based on the received inputs. This approach is efficient and comprehensive method in the sense that it is not susceptible to the value of fault impedance, it is applicable for symmetrical and asymmetrical faults, transposed and untransposed lines, identical and non-identical circuits, and both short and long double circuit transmission lines. Finally, the method converges quickly in maximum three iterations although it is iterative. Numerous case studies by changing the line length, fault impedance, location of fault, line characteristics and noise level are carried out using distributed line model to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Wind and solar power are expected to play important roles in many countries to achieve carbon neutrality; however, their inherent instabilities pose significant threats to existing power grids. Because hydropower has been recognized as a viable compensatory resource for solar and wind energy uncertainties, many studies have sought to determine optimal scheduling strategies for hydro-PV, hydro-wind, and hydro-PV-wind systems. However, few studies have simultaneously considered the sizing and scheduling of large-scale hydro-PV-wind hybrid systems connected to long-distance transmission lines. Therefore, this paper develops a mathematical metric to measure the wind and solar output complementarity and incorporates it into a multi-objective sizing and scheduling model for a hybrid hydro-PV-wind system, in which resource complementarity, profit generation, system reliability, and power curtailment trade-offs are concurrently considered. The ɛ -constraint method is employed and decision makers' attitude parameters are introduced to transform the proposed model into its equivalent single objective form. A case study in China reveals that the maximum wind and solar power output complementarity rate can be at least 0.19 for the studied hybrid hydro-PV-wind system. The incorporation of wind enables the hybrid hydro-PV-wind system to provide 4.11% more load than a hydro-PV system. In addition, if 2% of power curtailment is permitted, 1.53% more load can be served and 14.9% higher profits can be earned. To better explore the application of hybrid systems, management recommendations are provided for system operators, the power industry, and management administrations. • Multi-objective sizing and scheduling method for the hybrid renewable system is proposed. • Mathematical metrics to measure wind and solar power complementarity is provided. • A complementarity rate of 0.19 can be reached with 100% reliable service and no curtailment. • Integrating wind power into the hydro-PV system can reliably serve 4.11% more load. • An optimal rather than minimal level of the renewable power curtailment is more efficient. [ABSTRACT FROM AUTHOR]

• The accuracy and efficiency of a nonlinear spring-based modeling method are emphasized. • Seismic responses of an OTL under depth-varying ground motions are analyzed. • SSI and DVSE are incorporated in the failure mechanism prediction of an OTL. • The SSI effect on the seismic performance of an OTL is discussed utilizing fragility curves. Overhead transmission lines (OTLs) are responsible for long-distance electric power transmission from power plants to end-users, inevitably passing through seismically active regions. A thorough literature review regarding seismic design and assessment of various structures underscores the significance of incorporating soil-structure interaction (SSI) and depth-varying spatial effect (DVSE). However, previous studies typically assumed that OTLs are fixed directly to the ground, and depth-varying ground motions (DVGMs) are oversimplified as uniform excitations, which may yield questionable structural performance estimations. To address this concern, this paper focuses on investigating the SSI effect on the seismic response and failure mechanism of an OTL subjected to DVGMs. Prior to this investigation, two commonly used methods for modeling the SSI effect in software ABAQUS are compared, with a nonlinear spring-based modeling method deems comparable in accuracy yet superior in efficiency. Subsequently, a refined finite element model of an OTL-soil-pile system is developed utilizing this simplified modeling method, and a group of three-dimensional ground motions varying within layered soils is stochastically synthesized. The influences of SSI and DVSE are systematically explored in terms of the seismic responses, failure mechanisms, and fragility probabilities of the OTL. The results expose the potential of the SSI effect to weaken the seismic capacity of the OTL and increase the risk of failure, while disregarding the DVSE is likely to lead to overestimated outcomes. This research is expected to raise awareness of considering SSI and DVSE in the seismic design and analysis of OTLs. [ABSTRACT FROM AUTHOR]

• A flexibility enhancement pre-selection strategy based on network flexibility balance degree and line outage distribution factor is proposed. • The available flexibility index (AFI) is proposed to quantify the supply of system flexibility. • An optimization model of power system flexibility enhancement method based on pre-selection of structure adjustment strategy is proposed. The flexibility enhancement method of power system usually focuses on node flexible resource, without considering the transmission process. It may result in some flexible resources not being transferred, thus affecting the accuracy and effectiveness of the flexibility enhancement. In this paper, a flexibility enhancement optimization model based on pre-selection method of structure adjustment strategy is proposed, which can improve system flexibility with guaranteed availability of flexible resources. Firstly, the flexibility enhancement pre-selection method based on power system topology adjustment mathematical formulation is proposed to select the lines suitable for topology adjustment. Secondly, a flexibility enhancement optimization model considering economy and available flexibility is developed, which takes the maximum available flexibility index as the objective function and ensures the system flexible and economical by cost-floating constraint. The available flexibility deviation constraint corrects the system flexibility supply to guarantee the accuracy of available flexibility. Finally, the effectiveness of the proposed method is investigated through the case study on modified IEEE 24-bus and IEEE 118-bus system. [ABSTRACT FROM AUTHOR]

The present attempt is to design a novel approach for the numerical solution of fractional telegraph equation. The novelty of the paper exist in solving the time fractional telegraph equation with differential quadrature method based on cubic B-spline (MHB-DQM) for the fractional parameter 1 < γ < 2. Telegraph equation is used in electric transmission line to find distance and time. The fractional derivative involved in the equation is discretized using Caputo derivative. On the other hand, the terms involving space derivatives are approximated by fusion of differential quadrature method with modified version of cubic B-spline. Here B-spline acts as a basis to compute the weighted coefficients of differential quadrature method. This phenomenon reduce the PDE to the system of equations, which then are solved using suitable numerical technique. A matrix based technique is used to ensure the stability of the proposed scheme. Feasibility and applicability of this algorithm is performed using test problems. Approximate solutions obtained by MHB-DQM is portrayed through graph and tables in an interactive way. These results show that solution converges for smaller values of time and at various values of fractional parameter. [ABSTRACT FROM AUTHOR]

• A hybrid method is proposed for accurate detection of high impedance fault. • Empirical mode decomposition is used for feature extraction. • EMD with deep learning technique obtained better accuracy in distribution system. • Approximate fault location also identified by proposed technique. An uninterrupted and well-managed energy distribution system requires an effective protection system against various faults and uncertainties. Power system networks have a built-in issue called High Impedance Faults (HIFs), which can't be detected by standard protection mechanisms. This paper deals with the aforementioned issue by combining a deep learning technique (DLT) with a signal decomposition method known as Empirical Mode Decomposition (EMD). This approach utilizes the EMD for the extraction of multiple features from the input current signal, and LSTM neural network is employed for the accurate classification of HIF signals. The comparison results with various EMD methods and various switching events are also performed. Finally, this paper proposes an approximate location identification of HIFs. The simulation results demonstrate the effectiveness of the proposed method for detection in various fault scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

The transmission system plays a vital role in the electric power system as it links load centers with power generation and, so, it is mandatory to protect this system from any abnormal conditions. This paper proposes a novel reliable fault detection and location technique based on optimally allocated phasor measurement units. The optimal phasor measurement units allocation guarantees the full observability of the system including all transmission lines, which are impeded in the protection zones. The proposed fault detection and location technique depends on the measured positive sequence components. The proposed technique has essential advantage due to its generalization to be valid for different areas' sizes and configurations. The detection technique relies on calculated admittance, while the fault location is independent on fault resistance. For validation of the proposed technique, it is applied on the IEEE 14-bus system simulated using Matlab/Simulink® software package. Various faults are simulated considering fault resistance. From the simulated fault cases, the proposed technique proves its security against external faults and the dependability with internal faults. [ABSTRACT FROM AUTHOR]

Femtosecond (fs) laser, as an efficient and precise microfabrication tool, has been widely used in material processing. Superhydrophobic surfaces have many applications in anti-icing, self-cleaning and frost resistance. In this paper, nested micro/nanostructures were induced by fs laser on the surface of alumina ceramics. After modification by polydimethylsiloxane (PDMS), the ceramics surface induced by fs laser changes from superhydrophilicity to superhydrophobicity. The anti-icing and frost resistance of functional ceramics surface were studied. Scanning electron microscope (SEM) images show that the cross-scanning laser processing mode can induce the nested micro/nanostructures on ceramics surface, resulting in excellent superhydrophobic surface with water contact angle (WCA) up to176.39° and water rolling angle (WRA) as low as 1°. The experimental results show that the dynamic process of droplet icing on superhydrophobic surface includes three typical states, and the freezing delay time of droplet is mainly caused by the change from the liquid phase to the ice shell. The freezing delay time of the superhydrophobic surface is 189 s laser than that of the intrinsic ceramics surface. In addition, the distance between the adjacent condensation droplets on superhydrophobic ceramics is larger than that on intrinsic surface, which can effectively prevent the diffusion of frost. The superhydrophobic ceramic with frost resistance and anti-icing has a wide application in power transmission lines, aircraft, wind turbine blades, air conditioning pipe and chemical production. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries degradation can be classified into capacity reduction and increase of the internal resistance. Accurate estimation of the degradation is important to determine the economic value and the remaining useful life of the battery. This paper proposes a method which analyzes the transient voltage response at the early stage of discharge, starting from the fully charged state. An equivalent circuit composed by a series resistance and a Warburg element is adopted to fit the transient voltage. The Warburg element is modeled as a transmission line composed by a ladder of resistances and capacitances. The method is validated with data obtained before and after aging cycles performed at 1.4 C charge and 2.0 C discharge rates, at 25 °C, 10 °C and −5 °C. The loss of cyclable lithium is deemed to be the main reason behind the battery degradation at all the tested temperatures. The dependency of the Warburg parameter to the remaining cell capacity is the same regardless of the aging temperature, suggesting that estimation of the Warburg parameter provides information about the state of health of the cell. On the other hand, the relationship between the capacity reduction and the increase of resistance has a temperature-dependent slope with low increase at lower temperatures where lithium plating is likely to occur. Accordingly, a relatively low resistance increase is deemed to be the sign of lithium plating. [Display omitted] • Analysis of degradation based on the voltage response at the early stage of discharge. • The equivalent circuit includes a resistance (R s) and a Warburg element (W). • The method is validated on cells aged with fast charging at 25 °C, 10 °C, −5 °C. • W provides a measure of the capacity and R s is an indicator of possible lithium plating. [ABSTRACT FROM AUTHOR]

The design of the Transmission Line (TL) as a part of the Electron Cyclotron Heating (ECH) system for Divertor Tokamak Test facility (DTT) is approaching the conceptual design maturity. With an ECH system of 16 MW installed for the first phase and with a total of 32 gyrotrons (170 GHz, ≥ 1 MW, 100 s) the TL design is undertaking the challenge of an evacuated Multi-Beam TL (MBTL) concept to deliver the large number of beam lines from the gyrotron hall to the torus hall buildings. The system is organized in 4 clusters, each of them including 8 beamlines. The routing consists of single-beam TL section used to connect the gyrotron output to a beam-combiner mirror unit for each cluster, a common MBTL running in a suspended corridor reaching the Tokamak building and a beam-splitter mirror unit to connect to the ex-vessel optics and launchers sections located in the equatorial and upper ports of one sector, for a total of 4 DTT sectors. The TL mirrors will be actively water cooled to cope with the heat load in long pulses due to the high power incident radiation, with the possibility to include advanced concepts for the cooling design compatible with additive manufacturing technology. The characteristics of the system and its components are presented, showing both the progress of the adopted solutions and the current design. Since the main challenge of this TL is to maintain the overall losses below 15%, in this paper we present the expected ohmic and spillover losses, including beam coupling simulations evaluating losses given by high order Transverse Electro-Magnetic modes (i.e. aberrations). We describe how the effects have been estimated with electromagnetic simulations and how losses could be mitigated, since TL efficiency could significantly drop due to the presence of non-idealities, like the deformations of mirrors surface ascribed to the microwaves heat loads and possible misalignments and aberrations effects occurring along the line. [ABSTRACT FROM AUTHOR]

• Reflected signal (S11) peak successfully detected EOC, ECC, & EECC damage in ADTL. • Corrosion on damaged ADTL was studied using change in magnitude & FW3QM of S11 peak. • FW3QM of S11 peak from damage was used to track corrosion propagation in ADTL. • Deeper damage in ADTL cause additional disturbance in the passing through signal. • S11 shape of EECC cable represent antenna signal in equally spaced reflected peaks. Corrosion in aircraft structures and systems persists to pose significant problem in the aircraft industry. It affects both the aircraft structures and all the wiring systems including data transmission lines at the points of mechanical damage (missing or damaged insulation and jacket materials) and connections. Reliability of data transmission through aircraft data transmission lines (ATDL) is essential for maintaining performance capability and safety of flights. Unfortunately, there is no existing method for detecting corrosion and predicting its effect for wiring systems including ADTL. Detecting corrosion and predicting its effect on time would prevent unexpected system failures and catastrophes. This paper presents novel experimental method that has been employed, for the first time, to detect and study the effect of localized corrosion process on reflected and transmitted power signals passing through locally corroded ADTL with mechanically induced damage. ADTL with three types of induced damage were corroded in a Q-Fog cyclic accelerated corrosion chamber for over 14 weeks (2352 h) using ASTM G85-A5 Prohesion test that resembles the environment of aircraft operation. Cable specimens were taken out every week and investigated by measuring transmitted and reflected power signals passing through the corroded ADTL using Vector Network Analyzer (VNA), where signals from 0 to 6 GHz were swept into the ADTL. Reflected and transmitted power signals (S11 and S21 respectively) were acquired in time domain and processed in MATLAB. Analysis of results show that corrosion effect is not arbitrary and can be tracked over time and predicted. Reflected signal peak width changed over time of corrosion exposure and is proportional to corrosion propagation width inside the ADTL. It is also observed that corrosion induced extra distortion of signals passing through the corroded damage region. The results are very promising for detecting corrosion and predicting its effect in ADTL. [ABSTRACT FROM AUTHOR]

• Proposals of different CAD designs of a parabolic mirror (and its cooling channel) of the Multi-Beam Transmission Line of DTT ECH system. • Thermal and structural analyses to choose the best design configuration. • Optimisation of mirror performance on the best configuration found, in terms of thickness and hydraulic parameters. • Complete transient thermo-structural analysis on the optimized configuration. The Italian tokamak DTT (Divertor Tokamak Test) is a facility for research on nuclear fusion with the aim of investigating alternative power exhaust solutions to be exploited in the future DEMO fusion power plant. DTT foresees three additional heating systems to provide the plasma with sufficient power: Electron Cyclotron Heating (ECH) is the main one, with up to 32 MW installed. It consists of 4 clusters, each one composed of eight radio-frequency sources (gyrotrons) with their single-beam transmission lines, one quasi-optical Multi-Beam Transmission Line (MBTL) and eight independent launchers. The power produced by the source is transmitted quasi-optically through multiple reflections on metallic mirrors, the basic component of the transmission line, and then injected into the plasma. In the MBTL the reflection of the eight microwave beams on the mirror surface leads to heating of its whole structure due to the absorbed fraction of the beam power (0.21–0.27 %) ascribed to the ohmic heating at the mirror surface. During the radio-frequency power pulse (100 s), the mirror temperature increases, generating deformations that could result in a loss of beam transmission efficiency. For this reason, these mirrors need to be carefully designed from thermal and structural points of view, to guarantee the required optical performances. In the present paper, a preliminary study concerning the design of the MBTL parabolic mirror, and its cooling is presented, resorting to a coupled thermal and structural finite element simulation. The preliminary analyses address a main objective: minimize the surface mirror temperatures and consequently the deformation associated with thermal expansion, to reduce the impact on beam transmission efficiency drop. Different design choices, namely materials, body thickness and cooling solutions, in terms of cooling channel shape and water flow, are discussed. [ABSTRACT FROM AUTHOR]

• Based on the heat transfer theory and Thermal-Electric module, a simple method for quickly predicting the maximum temperature of water-cooled busbar with connector is proposed, which is convenient for engineering application. • Compared with V-T method and experimental results, the simple method in this paper has the advantages of global temperature distribution analysis and better temperature prediction accuracy, and can be used for the design of the same type of transmission lines. • The relationship among cooling water flow rate, contact resistance and maximum temperature of CRAFT busbar under rated working condition is determined, which can provide reliable guidance for actual operation of busbar. Due to the shortcomings of time-consuming and complicated operation of traditional fluid software simulation, a simple temperature prediction method that can quickly determine the reasonable working parameters of water-cooled busbar with connector is needed in the design of fusion power supplies. In this paper, considering the influence of contact resistance, the connector maximum temperature under same working conditions is studied by two kind of methods (combination method of heat transfer theory and Thermal-Electric module in ANSYS, Contact Voltage-Temperature (V-T) method), respectively. The comparison between simulation and experimental results shows that this method has the advantage of analyzing the global temperature distribution and predicting the maximum value more accurately than the latter. Based on this method, the relationship among contact resistance, water flow rate, and maximum temperature of the busbar connector used in Comprehensive Research Facility for Fusion Technology (CRAFT) is determined. This method can be applied to the rapid temperature analysis of fusion power busbar connector, which greatly reduces the design cycle. [ABSTRACT FROM AUTHOR]

This paper proposes a neural architecture search algorithm for obtaining an optimum Transformer model to detect and localize different power system faults and uncertain conditions, such as symmetrical shunt faults, unsymmetrical shunt faults, high-impedance faults, switching conditions (capacitor switching, load switching, transformer switching, DG switching and feeder switching), insulator leakage and transformer inrush current in a distribution system. The Transformer model was proposed to tackle the high memory consumption of the deep CNN attention models and the long-term dependency problem of the RNN attention models. There exist different types of attention mechanisms and feedforward networks for designing a Transformer architecture. Hand engineering of these layers can be inefficient and time-consuming. Therefore, this paper makes use of the Differential Architecture Search (DARTS) algorithm to automatically generate optimal Transformer architectures with less search time cost. The algorithm achieves this by making the search process differentiable to architecture hyperparameters thus making the network search process an end-to-end problem. The proposed model attempts to automatically detect faults in a bus using current measurements from distant monitoring points. The proposed fault analysis was conducted on the standard IEEE 14 bus distribution system and the VSB power line fault detection database. The proposed model was found to produce better performance on the test database when evaluated using F1-Score (99.4% for fault type classification and 97.7% for fault location classification), Matthews Correlation Coefficient (MCC) (99.3% for fault type classification and 97.6% for fault location classification), accuracy and Area Under the Curve (AUC). The architecture transferability of the proposed method was also studied using real-world power line data for fault detection. [ABSTRACT FROM AUTHOR]

Thyristor-Controlled Series Capacitor (TCSC) is used to control the active power flow in transmission lines in the power system to specific values. This paper proposes a simple modeling of TCSC into Newton-Raphson load flow algorithm in order to reduce the complexity and enhance the reusability of the original load flow code. TCSC is represented by two injected loads at the sending and auxiliary buses. These loads are calculated based on the specified active power while the reactive power is calculated based on the systems. The reactive loads are updated during the iterative process until the convergence is achieved. TCSC parameters are calculated based on the voltages of connected buses and the specified active power. This model solves the problem associated with the selection of proper initial values of the TCSC control parameter. The proposed TCSC model is validated using the standard IEEE 14-bus, IEEE 30-bus and IEEE 118-bus test systems. [ABSTRACT FROM AUTHOR]

• Environmental justice analysis shows inequitable hurricane recovery in Puerto Rico. • Central rural communities and Black communities were last to have power restored. • EJ index construction requires contextual environmental and demographic variables. • Disaster recovery policy must incorporate justice and equity. This paper uses an environmental justice framework to explore whether existing vulnerabilities in Puerto Rico are associated with the rate of electricity restoration after Hurricane María. Based on the literature discussing the relationship between vulnerability and environmental justice, we expected that the areas identified as vulnerable to environmental injustice would recover more slowly than less vulnerable areas. We use regression analysis to analyze how well three vulnerability indices based on environmental justice variables predict electricity restoration. We also map the resulting data to spatially situate recovery patterns. This analysis produces mixed evidence of our predictions. In addition to environmental justice factors, other factors, such as terrain and proximity to electric transmission lines, also affected recovery rates, complicating the narrative of recovery. These findings suggest that policymakers seeking to mitigate vulnerability to electricity outages in the wake of natural disasters should incorporate environmental justice analysis in their recovery prioritization decisions, and that this analysis should be contextually specific to the recovery area. Our analysis also includes the construction of environmental justice indices, which have the potential to be a useful advocacy tool for communities seeking to uncover the priorities of stakeholders engaged in recovery. [ABSTRACT FROM AUTHOR]

Recent reports indicate that electric vehicle charging stations (EVCSs) are susceptible to remote exploitation through their vulnerable software/cyber components. More importantly, compromised EVCS can be leveraged to perform coordinated oscillatory load attacks against the interconnected power grid, leading to power grid instability, increased operational costs, and power line tripping. In this paper, an edge-based approach for the detection and localization of coordinated oscillatory load attacks initiated by exploited EV charging stations against the power grid is investigated. The edge-based detection relies on the behavioral characteristics of the power grid in the presence of interconnected EVCS while combining cyber and physical layer features to implement deep learning algorithms for the effective detection of oscillatory load attacks at the EVCS. The proposed detection approach was evaluated by building a real-time test bed to synthesize benign and malicious data, which was generated by analyzing real-life EV charging data collected during recent years. The results demonstrate the effectiveness of the implemented approach with the Convolutional Long-Short Term Memory model producing optimal classification accuracy (99.4%). Moreover, this analysis results shed light on the impact of such detection mechanisms towards building resiliency into different levels of the EV charging ecosystem while allowing power grid operators to localize attacks and take further mitigation measures. Specifically, the detection mechanism of oscillatory load attacks is decentralized and created an effective alternative for operator-centric mechanisms to mitigate multi-operator and Man-in-the-Middle (MitM) oscillatory load attacks against the power grid. Additionally, the created test bed is leveraged to evaluate a distributed mitigation technique, which can be deployed on public/private charging stations to average out the impact of oscillatory load attacks while allowing the power system to recover smoothly within 1 second with minimal overhead. Finally, a security metric is createdto evaluate the resiliency of the ecosystem based on its design and architecture. • Creating an edge-based detection mechanism of oscillatory load attacks hosted on Electric Vehicle Charging Stations (EVCSs). • We introduce a distributed mitigation mechanism that is hosted on EVCS that deprives the adversary the ability to synchronize attacks. This was also demonstrated on a co-simulation platform. • Create a security metric that helps evaluate the resiliency of the ecosystem by taking into consideration various components. [ABSTRACT FROM AUTHOR]

Superconducting fault current limiters (SFCLs) offer an efficient means of limiting fault currents and supporting system reliability. However, they weaken the fault characteristics and reduce the sensitivity of traditional relay protection. The seamless integration of SFCLs with protective relays remains a complex and under-explored area, impeding their widespread industrial adoption. In parallel, current differential protective (CDP) relays are almost the primary protection for all high-voltage electrical equipment and are the cornerstone of global power system security. This paper fills a critical knowledge gap by researching the intricate interaction between resistive superconducting fault current limiters (R-SFCLs) and current differential protective relays. Our investigation commences with a comprehensive mathematical analysis, while researching the influence of R-SFCLs on CDP operation. Subsequently, we conduct a series of comparative experiments using the Matlab Simulink software platform. These tests evaluate the sensitivity, dependability, and security of CDPs in scenarios with and without R-SFCLs. The simulation results not only confirm the accuracy of our analytical framework but also shed light on the multifaceted relationship between R-SFCLs and CDPs. This research contributes to a deeper understanding of how R-SFCLs can be effectively integrated into power systems, offering a roadmap for enhancing grid protection. • Innovative Integration and Mathematical Analysis: This study presents a comprehensive exploration and rigorous mathematical analysis of the challenges in integrating Resistive Superconducting Fault Current Limiters (R-SFCLs) with current differential protective relays (CDPs) in power systems. It revealed the relationship between these components, providing a theoretical foundation for their integration. • Simulink Experiments and Validation of Framework: Extensive comparative experiments conducted using Matlab Simulink offer practical insights into the behavior of R-SFCLs and CDPs under various fault scenarios. The simulation results validate the accuracy of the analytical framework, confirming its effectiveness in addressing key challenges such as fault current limitation and relay sensitivity improvement. • Practical Implications and Contribution to Grid Protection: The study offers practical recommendations for effectively incorporating R-SFCLs into power systems, enhancing grid protection without compromising the reliability and sensitivity of protective relays. It contributes to the field of electrical power and energy systems, providing insights with the potential to influence industrial practices and enhance grid resilience. [ABSTRACT FROM AUTHOR]

Traditionally, the problem of congestion arising in power system networks due to various contingencies and varying renewable generation is addressed by optimal power flow-based methods, once in every 5–30 min. As these techniques are performed for a block period of time using forecasted data, they are not effective in real-time congestion mitigation through corrective actions. This paper proposes a controller-based approach for real-time congestion management through line power flow regulation. We consider a robust H ∞ power flow tracking control strategy to regulate the line power flows to the specified limit, while attenuating the effect of disturbances on the system. Using synchrophasor measurements from the lines, the proposed controller can detect line overloading and automatically re-dispatch the selected generators and battery energy storage systems to maintain power flow within the desired limit. The robust line power flow tracking problem with disturbance rejection is formulated as a dynamic game between the controller and disturbance entities, and robust static output feedback H ∞ controller gains are obtained via an iterative algorithm. The efficacy of the proposed controller in regulating line power flow and mitigating congestion is verified by extensive simulations on a 16-machine 68-bus test system and Kundur's 4-machine 2-area test system. It is shown that the designed controller can regulate line power flows within 40–60 s, which is fast enough to avoid overheating of transmission lines. Furthermore, the proposed strategy is simple from the perspective of design and implementation, and outperforms the existing congestion management techniques. • Line power flows can be regulated to specified operating limits with the controller. • Congestion in the network can be cleared automatically in short period of time. • Effect of disturbances are attenuated to a prescribed level to provide robustness. • Requires only power flow measurements from lines to implement robust control action. [ABSTRACT FROM AUTHOR]