Search Results (356)

Transport decarbonization through electric mobility depends not only on how many charging stations are deployed but where, and whether expansion balances accessibility, grid readiness, land-use protection and regional equity. Türkiye, targeting net-zero by 2053 with electric car sales exceeding 10% of the market in 2024, shows a highly uneven charging network: provincial provision ranges from 9.0 to 155.6 points per 100,000 inhabitants, with the least-served half of the population holding only 22.3% of installed capacity (Gini = 0.311). This study develops a GIS-based multi-criteria framework treating charging expansion as a sustainability-constrained planning problem. Six criteria, namely population, GDP, transformer and transmission-line proximity, road-network proximity, and city-centre proximity, were harmonized to a 100-m grid via fuzzy membership functions, with an exclusion mask protecting sensitive land uses. Three weighting scenarios were compared: equal weights (EVCSI-A), Random Forest-derived weights (EVCSI-B), and expert AHP weights (EVCSI-C). Road accessibility (41.12%) and economic capacity (29.84%) dominated existing placement, explaining ~71% of feature importance, stable across algorithms and bootstrap replicates. National results reveal an efficiency–equity trade-off: EVCSI-B concentrates suitability in metropolitan corridors, EVCSI-A preserves broader coverage, and EVCSI-C reinforces metropolitan bias. Central and Eastern Anatolia remain underserved. We recommend sustainability-constrained screening followed by grid-capacity verification, positioning EVCSI as a transferable equity-monitoring tool supporting SDG 7, 9, 11 and 13. Full article

Two breakwaters were constructed between 1959 and 1961 by the U.S. Army Corps of Engineers to form a harbor within Half Moon Bay on the central California coast. Prior to construction, the bay had a smooth hook-shaped or spiral form with a shoreline in equilibrium with waves refracted around a resistant point. Following breakwater completion, wave energy that had previously been dissipated along the equilibrium shoreline of the bay was concentrated at the downcoast end of the breakwater against the low weak bluffs. The original very low (~8 cm/year) bluff recession rates increased rapidly to as much as 2 m/year which led to the destruction of a county road and wastewater transmission line and began to threaten a state highway and a group of homes. Bluff erosion has progressed as far as 1.4 km downcoast which has led to rock revetment placement to protect the highway and homes. Breakwater planning also underestimated the potential for waves to enter the gap between the two breakwaters, so a dogleg extension had to be constructed. This also failed to reduce wave action, which led to the construction of an additional set of breakwaters within the harbor to protect moored boats. Full article

Accurate fault diagnosis and protection of series-compensated transmission lines remain challenging due to the nonlinear behavior of series capacitors and associated protective devices, which degrade the performance of conventional protection relays under varying operating conditions. To address these challenges, this paper proposes an intelligent ensemble learning-based protection framework for fault detection, fault classification, fault section identification, and fault location estimation in fixed series-compensated transmission networks. The proposed framework integrates an Artificial Neural Network (ANN) and a random subspace ensemble classifier (RSEC), where the ANN performs fault detection, classification, and location estimation, while the RSEC identifies the faulted section using a majority-weighted voting strategy. In addition, four fault indices are formulated to effectively characterize fault conditions and improve diagnostic performance. The proposed framework is evaluated on a 400 kV, 50 Hz series-compensated transmission system under diverse fault scenarios and varying operating conditions, including different fault types, fault resistances, fault locations, compensation levels, and noisy measurements. The results demonstrate an average fault detection time of 4.05 ms, 100% fault classification accuracy, 98.646% fault section identification efficiency, a mean signed fault location error of −0.02988%, and a mean absolute location error of 0.0791%, indicating negligible systematic bias and high localization accuracy. Furthermore, real-time validation using the OPAL-RT digital real-time simulator confirms the computational feasibility of the proposed framework, demonstrating its potential as a reliable, accurate, and computationally efficient solution for intelligent protection and monitoring of modern smart transmission networks. Full article

Optical ground wire (OPGW) cables are subjected to extreme electromagnetic stresses from lightning and short circuits. Existing models have three main limitations: (i) they assume uniform current distribution, (ii) they use constant material properties, and (iii) they do not couple the electromagnetic, thermal, and mechanical domains. This paper proposes a coupled multiphysics model that incorporates non-uniform current distribution with ${\mu }_r$ dependent on the magnetic field, temperature-dependent properties, and differentiated failure criteria. The model was implemented in COMSOL Multiphysics and was validated against experimental short-circuit tests (15–30 kA) conducted at the HPT-Laboratory (FEC). For the lightning scenario (10/350 μs impulse), the model predictions were compared with experimental results reported in the literature, showing good agreement in temperature rise and damage patterns. Results show that including a non-uniform current distribution modifies the predicted maximum temperature by 15.8% and shifts its location from the center to the outer aluminum layers. The model reproduces the experimental temperature with an RMSE of <7 °C and a relative error of <8%. A combined failure criterion (thermal + mechanical) predicts strand breakage with 89.2% accuracy, outperforming the purely thermal (72.5%) and mechanical (78.3%) criteria. Specific $I-t$ and $I^{2}t$ curves were generated for two commercial OPGW cable configurations (Manufacturer A and Manufacturer B), with $I^{2}t$ capacities at 500 ms of 128 kA²s and 98 kA²s, respectively. The proposed model provides a useful tool for protection selection and coordination in transmission lines with OPGW cables. Full article

The overhead ground wire (OGW) may fracture at the suspension clamp under short-circuit faults, posing a serious threat to the safe operation of transmission lines. However, the dominant damage mechanism—whether Joule heating or arc discharge—remains unclear. This study investigates a 110 kV OGW breakage accident through combined experimental and numerical approaches. Fracture analysis using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) revealed composite damage featuring both melting and tensile necking, with no fatigue characteristics. A real-scale short-circuit test platform was constructed, which, for the first time, directly captured intense arc discharge phenomena inside the suspension clamp during current flow. A multi-physics finite element model was then developed to decouple and quantify the thermal contributions of Joule heating and arc heating. Results show that Joule heating alone raises the local temperature to only 49.27 °C—far below the melting points of aluminum (660 °C) and steel (1450 °C). In contrast, arc heating elevates the temperature to over 26,000 °C locally, causing rapid melting of aluminum strands and heating of the steel core above 1450 °C within milliseconds. This extreme heat reduces the effective load-bearing cross-section and tensile strength, ultimately leading to fracture under normal operating tension. The findings demonstrate that arc discharge, rather than Joule heating, is the decisive factor in such failures. This study provides a quantitative theoretical basis for fault protection and hardware design optimization of overhead transmission lines. Full article

Accurate and fast fault detection is essential to ensure the stability and reliability of High Voltage AC (HVAC) transmission systems. Conventional protection methods, including impedance-based and traveling wave techniques, may exhibit reduced performance under noisy operating conditions, system uncertainties, and complex fault scenarios while often requiring separate approaches for fault classification, location detection, and stability assessment. This paper proposes a unified Artificial Neural Network (ANN) based framework for simultaneous fault classification, location detection, and stability assessment using Critical Clearing Time (CCT) within a single HVAC transmission line model. A detailed MATLAB Simulink model is developed to generate a structured dataset comprising twelve fault scenarios, including single-line, double-line, three-phase, and ground faults at different locations along the transmission line. Three-phase voltages and currents, along with zero-sequence components, are used as input features. The ANN model is trained using the Levenberg–Marquardt (LM) optimization algorithm, which was comparatively evaluated against Bayesian Regularization (BR) and Scaled Conjugate Gradient (SCG) and demonstrated faster convergence, lower prediction error, and higher regression accuracy. To further evaluate the robustness of the proposed framework under high-impedance fault conditions, supplementary simulations were performed using fault resistance values of 10 Ω and 50 Ω in addition to the baseline 0.01 Ω case. The resulting datasets were combined to form an expanded training and evaluation dataset, enabling comprehensive validation of the proposed LM-trained ANN under varying fault resistance conditions. Using the baseline dataset, the proposed framework achieved a high regression coefficient (R = 0.9882) and low mean squared error (MSE = 0.1386), demonstrating accurate fault classification and precise per-kilometer fault location estimation. Furthermore, the integration of fault inception time and duration enables direct computation of CCT, allowing the model to distinguish between stability-critical and non-critical fault conditions. The results confirm that the proposed framework provides a comprehensive and efficient solution for real-time fault analysis by combining classification, localization, temporal analysis, and stability-aware decision support within a single model. Full article

Existing single-ended protection schemes for flexible DC transmission lines are negatively affected by traveling wave (TW) refraction and reflection interference and nonlinear overfitting under low-resistance faults. To address this, in this study, line-mode voltage reverse TWs are mathematically analyzed, revealing that internal faults and forward external faults exhibit single- and double-exponential attenuation, respectively. An adaptive constant-value flattening method is proposed to suppress subsequent TW refraction and reflection. Additionally, a composite fitting strategy utilizing Levenberg–Marquardt (LM) and Moore–Penrose pseudoinverse (PINV) algorithms is proposed to fit the measured waveforms, solving the problem of low-resistance overfitting and amplifying residual differences between internal and external faults. Based on these principles, a novel single-ended protection scheme is proposed. Simulations verify that this scheme exhibits a high operating speed and strong robustness against different fault distances, different fault resistances, and noise. Full article

Railway transportation networks increasingly share constrained corridors with transmission lines, buried pipelines, and other linear infrastructure. Electromagnetic interference in these corridors is important for safe railway planning and operation, particularly when nearby high-voltage lines cross oil and gas pipelines. This paper investigates transmission-line-induced pipeline potential under crossing conditions in the Zhangbei region. The CDEGS moment-method framework is applied with locally refined segmentation in the crossing regions, and an electromagnetic coupling model for multiple-crossing transmission line-oil and gas pipeline systems is established. The qualitative effects of crossing angle and parallel length on pipeline potential were obtained under both normal operating conditions and single-phase ground fault transient conditions. The results show that induced voltage decreases nonlinearly as the crossing angle increases and rises markedly with crossing length. The contribution of ground potential rise during transient processes to pipeline potential is significantly greater than that during steady-state processes. Installing zinc ribbons as a drainage measure can reduce the pipeline-to-ground voltage. However, supplementary mitigation measures may still be required under severe interference conditions. These findings are relevant to railway transportation because railway corridors often coexist with transmission lines and buried pipelines, making coordinated electromagnetic compatibility assessment essential for infrastructure safety and operational reliability. The proposed framework supports corridor planning, risk assessment, and protective design for railway-related infrastructure in complex shared corridors. Full article

Mucosal immunity in the respiratory tract provides the first line of defense against airborne pathogens, yet most current vaccines fail to induce strong and durable immune responses at these sites. Respiratory viruses, including respiratory syncytial virus (RSV), influenza viruses, and coronaviruses, remain major global health threats, in part due to their ability to evade long-term mucosal protection. Although systemic vaccination generates robust circulating immunity, it induces limited local responses, particularly secretory immunoglobulin A (IgA), which is critical for preventing viral entry and transmission at the airway surface. The mechanisms regulating B cell responses within the airway mucosa are not fully understood. B cell–activating factor (BAFF), a member of the tumor necrosis factor (TNF) superfamily, has emerged as an important context-dependent regulator of mucosal B cell immunity. BAFF is produced by airway epithelial cells and multiple myeloid populations, including dendritic cells and neutrophils, and is rapidly induced during respiratory viral infection through type I interferon–dependent pathways. Functionally, BAFF supports B cell survival, differentiation, and class-switch recombination, promoting the generation of antibody-secreting plasma cells and enhancing IgA production. In the lung, these effects align with early, intermediate, and late stages of the response, supporting initial local antibody production, the formation of inducible bronchus-associated lymphoid tissue (iBALT), and the development of tissue-resident memory B cells that sustain long-term immunity. Although BAFF plays an essential role in mucosal immunity, its activity requires tight regulation to maintain immune balance. Current evidence supports BAFF as a promising immunomodulatory component and highlights its potential as an adjuvant platform for enhancing mucosal vaccine efficacy, warranting further investigation as a potential adjuvant in this context. Full article

The paper details the implementation and experimental validation of an IEC 61850-9-2 sampled value (SV)-based distance protection scheme for a 132 kV transmission line. Instead of conventional analog interfaces, we propose a scheme that uses a digital process bus to stream time-synchronized voltage and current measurements from instrument transformers to protection relays. A laboratory-scale setup was developed, in which an SEL 401 merging unit samples currents and voltages injected by an OMICRON CMC 356 and publishes them as SV messages to an SEL 421 distance relay. This work demonstrates how IEC 61850-9-2 can be practically applied to modernize transmission line protection and enhance overall grid reliability and resilience. Full article

Power system parameters are susceptible to multiple influencing factors such as environmental conditions and load current, with line parameters being notably affected. This compromises the accuracy of power flow calculation and fault analysis, and can significantly undermine the reliability of protection schemes. To address these limitations, this study proposes an integrated correction method for power system line parameters via a framework that combines soil resistivity inversion and multi-factor sag calculation. First, based on fault-recording data from external line faults, sequence impedance parameters are calculated using a two-terminal impedance difference subtraction strategy, followed by the inversion of soil resistivity along the transmission corridor. Second, considering the spatial inhomogeneity of the transmission corridor, a sliding-window statistical method is applied to segment the line, and a piecewise series model is employed to correct the zero-sequence impedance parameter. Finally, a conductor temperature and sag model based on the heat balance equation is established. By coupling ambient temperature, wind speed, solar radiation, and mechanical load, the ground capacitance and susceptance parameters are dynamically corrected. Simulation results demonstrate that the proposed framework can systematically achieve dynamic correction of power system line parameters and significantly reduce calculation errors. The developed method provides an effective technical pathway for enhancing the accuracy of power system simulation and improving the reliability of protection schemes. Full article

Hybrid transmission corridors combining overhead lines and underground cables introduce impedance discontinuities that significantly modify electromagnetic transient behavior. These discontinuities generate traveling-wave reflections, waveform distortions, and high-frequency components at relay measurement locations during the first microseconds following disturbance inception. This paper presents a waveform-level electromagnetic transient (EMT) analysis of overhead–cable transition effects using detailed EMTP-RV simulations including frequency-dependent line and cable models, tower representations, grounding systems, and instrument transformers within a differential protection measurement framework. The results show that overhead–cable transitions produce transient waveform modifications characterized by reflections, attenuation, dispersion, and temporary current imbalance mechanisms associated with traveling-wave propagation and cable capacitive effects. The analysis also demonstrates the transient evolution of instantaneous waveform-derived (EMT-derived) differential and restraining current quantities, defined as combinations of terminal current signals obtained directly from EMT waveforms. These quantities do not represent final phasor-domain operating values of practical numerical relays, but provide insight into the transient electromagnetic environment preceding conventional filtering and phasor estimation. The study contributes to a clearer physical interpretation of transient phenomena in hybrid transmission systems and supports EMT-based evaluation of signals relevant to differential protection applications. Full article

Biosecurity is a key determinant of herd health, production efficiency, and disease prevention in modern pig farming under the continuing pressure of endemic and transboundary pathogens. The aim of this study was to assess external and internal biosecurity measures, together with selected disinfection-related practices, on 19 large commercial Hungarian pig farms representing farrowing, weaner, and fattening units. A convenience-sample, questionnaire-based survey was conducted between November 2020 and March 2021 among farm veterinarians, and the data were evaluated descriptively. Several external biosecurity elements were common, including perimeter fencing, careful animal sourcing, extended quarantine periods, and restrictive entry hygiene. However, weaknesses remained, particularly in feed-vehicle entry across the fence line, disinfection infrastructure, and feed storage protection. Internal biosecurity was more consistently implemented in farrowing, nursery, and fattening units than in sow units, while limitations in all-in/all-out management, airspace separation, inter-unit movement, hygiene barriers, and shared equipment management may increase within-farm pathogen transmission. These findings suggest that important biosecurity measures were widely applied, but their consistency and practical quality varied across key risk points. Owing to the small convenience sample, the results should be interpreted as descriptive findings for the surveyed farms. Full article

Facing the challenges in field monitoring of the mechanical response of geogrids in asphalt pavements, this study integrated two types of Fiber Bragg Grating (FBG) sensors, unarmored and armored, into geogrids using the pillar-stitching technique on industrial warp-knitting production lines. The integrated FBG-geogrid systems were comprehensively evaluated in both wound and flattened configurations, enabling the selection of a sensor type suitable for industrial production. After precise strain calibration, a full-scale field damage test was performed during the construction of the Qu-Gang Expressway in Hebei Province, China. The results demonstrate that the helical steel armor layer significantly enhances the mechanical durability of the FBG sensor. Specifically, the armored sensor maintained stable optical transmission over its entire 60-m length, with an average performance retention rate of 98.86% in the flattened state. Moreover, a strong linear correlation was established between the wavelength shift of the armored FBG sensor and the tensile strain of the geogrids. In contrast, the unarmored FBG sensor underwent irreversible shear deformation during production and contained at least two breakpoints. Additionally, a protection scheme employing fiberglass-reinforced silicone rubber on the hot side and standard silicone rubber on the cold side effectively shielded the sensors from high-temperature and compaction loads during asphalt paving. Consequently, the proposed FBG-geogrid integration method and the corresponding field protection strategy provide technical support for the real-time monitoring of geogrid performance in asphalt pavements and have significant engineering value. Full article

Due to the controlled characteristics of fault current in doubly fed wind farms and the distributed capacitance effects of transmission lines, traditional distance protection is prone to failure or maloperation during high resistance faults. To improve protection reliability, this paper proposes a novel time–domain distance protection scheme based on the hybrid-π model. First, the improved time–domain fault differential equations are formulated based on the hybrid-π model, incorporating ground capacitance and integrating electrical quantities at both ends of the line. Next, the composite weight matrix integrating transient mutation weights and fitting error weights is introduced and embedded within a nonlinear least-squares framework. This enables the algorithm to adaptively distinguish and suppress unreliable data, simultaneously achieving transient disturbance resistance and rapid steady-state convergence. Finally, a 220 kV double-fed wind power grid-connected system with a 100 km transmission line is built in MATLAB/Simulink for simulation. Different types of faults under various locations and transition resistances are simulated to verify the effectiveness of the proposed scheme. Full article