Search Results (172)

This paper presents a data-driven probabilistic framework for analysing power system faults using Monte Carlo simulations. The study evaluates the operational reliability of multiple high-voltage switchgear topologies—including single-busbar systems, double-busbar systems, and ring-type configurations—by modelling the stochastic behaviour of disconnectors, circuit breakers, busbars, and withdrawable switching elements with bypass arrangements. Realistic unavailability parameters derived from statistical reliability data are used to generate fault intervals for each device, enabling the simulation of millions of operational scenarios and capturing both full and partial outage events. The proposed methodology quantifies outage probabilities, identifies critical components, and reveals how devices count, switching logic, and system redundancy influence overall resilience. Results show significant reliability differences between topologies and highlight the importance of optimized substation design for fault tolerance. The developed probabilistic framework provides a transparent and computationally efficient tool to support planning, modernization, and predictive maintenance strategies in transmission and distribution networks. Findings contribute to improved fault diagnosis, enhanced grid stability, and increased reliability in both conventional and renewable-integrated power systems. Full article

The environmental and human health impacts of mono-crystalline silicon (mono-Si) module assembly in Mexico were estimated using a regionalized Life Cycle Assessment (LCA). A detailed inventory was completed through fieldwork consisting of arranged visits to four manufacturers to collect on-site data. The main findings demonstrate that, on average, between 10% and 35% of the photovoltaic cells imported from China for module assembly in Mexico are discarded during the manufacturing process. Furthermore, experimental studies conducted in our laboratories with samples collected from the manufacturing plants showed that the busbars and finger contacts on the cells and strings indicate the presence of lead and a lack of silver in the aluminum-based alloys used for soldering and coating the strings. The LCA study includes end-of-life scenarios, with particular attention to open-dump waste disposal, the most common option in Mexico, which generates three-times-greater environmental impacts than waste incineration. The impact of different transport options for importing cells from China yielded Global Warming Potential (GWP) values of 157.52 kg CO₂ eq and a Cumulative Energy Demand (CED) of 2204.9 MJ eq, compared to 8.9 kg CO₂ eq and 123.3 MJ eq, respectively, obtained for sea transport. These results highlight the importance of including transport and end-of-life scenarios to obtain realistic environmental and human health impacts from photovoltaic module manufacturing. Full article

Static voltage stability (SVS) is a critical aspect of the safe and efficient operation of electrical power systems (EPS), as it reflects the system’s ability to maintain adequate voltage levels in the face of progressive increases in demand under steady-state conditions. Traditionally, improving SVS has been addressed by compensating reactive power using FACTS devices. However, this research introduces an alternative methodology based on the hybridization of transmission technologies, integrating HVAC and HVDC links in parallel, to increase the stability margin and optimize performance in the event of contingencies. The proposed methodology is based on the resolution of the optimal AC power flow (OPF-AC) and the analysis of P-V curves to evaluate the displacement of the critical collapse point. The validity of the approach was verified through simulations in the Generation-Infinite Busbar and IEEE 9-busbar models, using the DIgSILENT PowerFactory environment. The results obtained show significant improvements in the SVS margin: an increase of 4.6% in the infinite busbar generation system, 9.5% in the critical busbar of the IEEE 9-busbar system, and 7.6% in the critical busbar of the IEEE 30-busbar system. In addition, the hybrid scheme showed a 17.1% reduction in real power losses and a more efficient redistribution of energy flows, which translates into a decrease in line load capacity. It should be noted that, under an N-1 contingency scenario, the hybrid system showed a 13.3% improvement in maximum power transfer before collapse, confirming its effectiveness under critical conditions. These findings position HVAC/HVDC hybridization as a robust and scalable alternative for strengthening voltage stability in modern electrical systems subject to operational variability. Full article

This paper reviews tab-to-busbar interconnections in lithium-ion battery packs, focusing on resistance welding (RW), laser beam welding (LBW), and ultrasonic welding (USW). The functional roles of tabs and busbars and typical material choices (Al-, Cu-, and Ni-plated Cu) are outlined. Subsequently, the processes are compared in terms of heat input, interfacial metallurgy, electrical resistance, mechanical robustness, and manufacturability. USW, as a solid-state method, suppresses porosity and limits Al-Cu intermetallic growth, but is sensitive to thickness, stack geometry, and tool wear. LBW enables high-speed, automated production with precise energy delivery, yet requires careful control to mitigate spatter, porosity, and brittle IMCs in dissimilar joints. RW remains cost-effective and flexible but can suffer from electrode wear and variability with highly conductive stacks. This review also summarizes the effect of the busbar material (Al versus Cu) and thickness on the connection resistance and temperature increase under a high current. No single process is universally superior, and the selection should match the stack-up, reliability targets, and production constraints. This paper aims to provide an overview of recent and conventional research trends for each welding method and to introduce selected non-traditional approaches, thereby presenting a range of viable options for future applications. Full article

Solidification cracking is a critical defect in Cu–steel dissimilar laser welding for cylindrical lithium-ion battery busbar assembly, yet the metallurgical role of phosphorus (P) in crack formation has not been quantitatively established. In this study, the influence of phosphorus in the coating layer on weld solidification behavior was clarified by preparing Cu substrates with four different coating conditions—Ni–P-coated Cu (10 and 50 μm) and pure Ni-coated Cu (10 and 50 μm)—and performing high-speed single-mode fiber-laser welding under identical heat-input conditions. Shear-tensile testing, EPMA-based microstructural analysis, and Thermo-Calc solidification calculations were combined to correlate P segregation with solidification cracking susceptibility. The Ni–P 10 μm coating generated severe solidification cracking compared with the pure Ni 50 μm coating, which was attributed to excessive P enrichment in the terminal liquid phase (up to 8.8 mass%). This enrichment significantly expanded the mushy-zone width to approximately 869 K, yielding a highly solidification crack-susceptible fusion zone. In contrast, 50 μm pure Ni coatings produced narrow mushy-zone widths (200–400 K) and extremely low residual P levels (~0.1 mass%), resulting in fully crack-free microstructures. The 50 μm Ni coating exhibited the highest shear-tensile strength and largest rupture displacement among all conditions, confirming that suppression of P segregation directly improves both structural integrity and mechanical performance. Overall, this study demonstrates that phosphorus enrichment critically governs the solidification-cracking susceptibility of Cu–steel dissimilar welds by widening the solidification temperature range. Eliminating P from the coating layer and applying an adequately thick pure Ni coating constitute highly effective strategies for achieving crack-free, mechanically robust welds in lithium-ion battery busbar manufacturing. Full article

The online diagnosis technology used to determine the internal thermal status and defects of GIS equipment is important. In the existing GIS bus thermal defect fault diagnosis methods, sensors are usually installed on the highest and lowest temperature areas of the enclosure surface, and then an artificial neural network is established to obtain the highest temperature inside the GIS. These methods only consider the temperature under steady-state conditions, and the temperature signals collected by sensors are different, which leads to low accuracy and weak generality. This paper investigated the transient temperature evolution characteristics defined as a sequence of temperature values over time, and adopted them as new features. The steady and transient enclosure and environment temperature data were used to train the Generalized Regression Neural Network (GRNN) for the inside busbar temperature inversion. Experimental tests proved that the proposed method has a higher accuracy compared to traditional characteristic parameters, especially for the less significant temperature rise. This article provides a technical means for determining the internal temperature rise status of GIS equipment through external temperature monitoring in practical applications. Full article

This study focuses on first-generation crystalline silicon photovoltaic (PV) cells, which remain the core of the PV industry. It outlines the structure and operation of single-junction cells, distinguishing between monocrystalline and polycrystalline technologies. A literature review was conducted using databases such as Web of Science and Scopus to identify research trends and inform future research directions. PV cell classification by generation is also presented based on production methods and materials. The experimental section includes both electrical and structural characterisation of crystalline silicon solar cells, with particular emphasis on the influence of the number and geometry of front-side busbars on metal-semiconductor contact resistance and electrical properties. Additionally, the paper highlights the use of dedicated laboratory equipment—such as a solar simulator (for determining photovoltaic cell parameters from current-voltage characteristics) and Corescan equipment (for determining layer parameters using the single-tip probe method)—in evaluating PV cell properties. This equipment is part of the Photovoltaics and Electrical Properties Laboratory at the Silesian University of Technology. The findings demonstrate clear structural correlations that can contribute to optimising the performance and longevity of silicon-based PV cells. Full article

Single-phase ground faults (SPGFs) in isolated neutral medium-voltage networks are difficult to detect, especially under high transient resistance. This paper proposes a centralized ground fault protection unit (CGFPU) that combines zero-sequence current (ZSC) magnitude and phase-angle analysis to enhance selectivity. Simulation results show that as transient resistance increases from 1 Ohm to 10 kOhm, fault currents decrease significantly, yet the CGFPU reliably identifies the faulty feeder by exploiting the characteristic 180° phase shift of ZSC phasors. The method remains selective with angular deviations up to ±20° and distinguishes between feeder and busbar faults. Compared with conventional amplitude- or model-based techniques, the proposed approach achieves faster detection, lower computational complexity, and robustness against unbalanced and charging currents. Furthermore, the CGFPU operates adaptively in alarm or trip mode depending on fault severity, thus preserving continuity for high-resistance faults and ensuring rapid isolation of bolted faults. These contributions establish a practical, scalable, and future-ready solution for SPGF protection in medium-voltage isolated neutral networks. Full article

Electrical cabinet fire is a prevalent type of electrical fire. It can result in significant casualties and major damage to residential dwellings, chemical plants, or other facilities. This study proposes an investigation methodology for electrical cabinet fires. It includes evidence collection and reasoning inference, reverse deduction, and comprehensive analysis. Using a cabinet fire as a case study, macro and micro trace analyses are performed utilizing a stereomicroscope, a scanning electron microscope, and an energy-dispersive spectrometer. The typical characteristics of traces, encompassing melting marks, arc beads, and displacement, are summarized. The evidence suggests that poor electrical contact is the primary cause. A thermal–electrical–mechanical coupling model is developed to simulate poor contact on copper busbars. The results reveal that thermal stress caused by local overheating can lead to the deformation and displacement of the busbar. The calculation indicates that the temperature rise triggered by poor contact can reach 1040 °C. The maximum displacement of the busbar caused by thermal stress is 6.2 mm. Force analysis indicates that one busbar will descend under gravity and come into contact with another busbar of a different phase. The short circuit triggered by direct contact caused fire. To prevent such accidents, it is essential to verify that the specifications of bolts correspond to those of screw holes to avoid poor contact. Furthermore, insulating plates should be installed between distinct-phase busbars to prevent short circuits. Full article

The growing demand for improved interruption performance characteristics in emerging aircraft high-voltage direct current (HVDC) electrical networks motivates the rapid development of solid-state power controllers (SSPCs). This article presents a comprehensive design procedure for a 270 V 300 A SSPC utilizing discrete SiC cascode devices. Due to the high fault current and limited power of single switches, parallel SiC FETs are essential for interrupting high fault currents in SSPCs. Consequently, the challenge of current balancing among parallel devices is addressed in this paper by adopting a passive current balancing strategy based on an irregular-shaped busbar. Furthermore, considering the voltage spikes arising from the power loop parasitic inductance and TVS characteristics during fault interruption, an RC-TVS-based transient voltage mitigation circuit is proposed to suppress these peak voltages. Moreover, thermal models for overload and short-circuit conditions were developed to optimize the thermal management system to ensure reliable operation of the SSPC. Finally, a prototype of 270 V/300 A SSPC has been built to validate the key characteristics of the proposed high power SSPC. Full article

This study examines the effects of hailstorms on photovoltaic (PV) modules, focussing on damage mechanisms, testing standards, numerical simulations, damage detection techniques, and mitigation strategies. A comprehensive review of the recent literature (2017–2025), experimental results, and case studies is complemented by advanced simulation methods such as finite element analysis (FEA) and smoothed particle hydrodynamics (SPH). The research emphasises the crucial role of protective glass thickness, cell type, number of busbars, and quality of lamination in improving hail resistance. While international standards such as IEC 61215 specify test protocols, actual hail events often exceed these conditions, leading to glass breakage, micro-cracks, and electrical faults. Numerical simulations confirm that thicker glass and optimised module designs significantly reduce damage and power loss. Detection methods, including visual inspection, thermal imaging, electroluminescence, and AI-driven imaging, enable rapid identification of both visible and hidden damage. The study also addresses the financial risks associated with hail damage and emphasises the importance of insurance and preventative measures. Recommendations include the use of certified, robust modules, protective covers, optimised installation angles, and regular inspections to mitigate the effects of hail. Future research should develop lightweight, impact-resistant materials, improve simulation modelling to better reflect real-world hail conditions, and improve AI-based damage detection in conjunction with drone inspections. This integrated approach aims to improve the durability and reliability of PV modules in hail-prone regions and support the sustainable use of solar energy amidst increasing climatic challenges. Full article

This paper presents a systematic approach to the development and validation of a monitoring and protection system based on the IEC 61850 standard, evaluated through hardware-in-the-loop (HIL) testing. The study utilized an already existing model of a modern power grid consisting of the IEEE 9-bus power system integrated with a large-scale wind power plant (LSWPP). The SEL-487B Relay was configured to protect the PCC using a low-impedance busbar differential monitoring and protection system equipped with adaptive setting group logic that automatically transitions between Group 1 and Group 2 based on system loading conditions. Significant steps were followed for selecting and configuring instrument transformers and implementing relay logic in compliance with IEEE and IEC standards. Real-time digital simulation using Real-Time Digital Simulator (RTDS) hardware and its software, Real-time Simulation Computer-Aided Design (RSCAD), was used to assess the performance of the overall monitoring and protection system, focusing on the monitoring and publishing of the selected electrical and mechanical measurements from a selected wind turbine generator unit (WTGU) on the LSWPP side through the IEC 61850 standard network, and on the behavior of the monitoring and protection system under initial and increased load conditions through monitoring of differential and restraint currents. The overall monitoring and protection system was tested under both initial and increased load conditions, confirming its capability to reliably publish analog values from WTGU13 for availability on the IEC 61850 standard network while maintaining secure protection operation. Quantitatively, the measured differential (operate) and restraint currents were 0.32 PU and 4.38 PU under initial loading, and 1.96 PU and 6.20 PU under increased loading, while total fault clearance times were 606.667 ms and 706.667 ms for faults under initial load and increased load demand conditions, respectively. These results confirm that the developed framework provides accurate real-time monitoring and reliable operation for faults, while demonstrating a practical and replicable solution for monitoring and protection at transmission-level PCCs within renewable-integrated networks. Full article

Voltage supraharmonics present in the electrical grid can trigger chain reactions in grid-connected household and industrial power supplies equipped with Power Factor Correction (PFC). A single source of voltage supraharmonics may significantly increase the current in switching devices with PFC, leading to higher-amplitude disturbances throughout the electrical network. When addressing issues in a real low-voltage (LV) grid, it was observed that activation of a single device emitting supraharmonics caused oscillating currents across all feeders connected to the transformer’s busbars, matching the frequency of the supraharmonic source. To investigate this phenomenon further, the grid voltage containing supraharmonics was replicated in a controlled laboratory environment and used to supply various power electronic devices. The laboratory results closely mirrored those observed in the field. Supraharmonics present in the supply voltage caused current oscillations in the power electronic devices at the same frequency. Moreover, the amplitude of the observed current oscillations increased with the amplitude of the injected supply voltage supraharmonics. In some cases, the root mean square (RMS) value of the current drawn by the power electronic devices doubled, indicating a substantial impact on device behaviour and potential implications for grid stability and energy efficiency. Full article

As a strong candidate for energy storage applications, Liquid Metal Batteries (LMBs) have the advantages of higher current density, longer cycle life, and simpler manufacturing of large-scale storage systems. Owing to the all-liquid construction, various kinds of Magnetohydrodynamic instabilities (MHDIs) are present in LMBs. In this paper, an in-depth study of the evolution process of MHDIs within LMBs has been conducted. By analyzing the characteristic velocity, the growth rate of instabilities γ has been defined so that the critical Hartmann number at which the instability occurs can be ascertained. A new critical parameter, mixed Reynolds number Re_mix, has been introduced to determine the duration of stable battery operation across varying charging/discharging currents, including those that may surpass the prescribed safe limits. Finally, a method for mitigating magnetohydrodynamic instability in LMBs through the configuration of busbar current is proposed, which can be seamlessly integrated with parallel battery packs. A comparative analysis of LMBs operation with/without bus current configuration reveals that when bus current is appropriately configured, the magnetic field strength within the battery undergoes a notable reduction of 40%, leading to a significant suppression of instability. The conclusions offer theoretical underpinnings for the application of LMBs in large-scale grid-level energy storage systems. Full article

The paper presents a method for selecting the locations of field sensors under a medium- or high-voltage line or substation busbars, in a contactless voltage measurement system. The proposed method uses the condition number of a distance matrix, correlated with the capacitance matrix of a system, as an optimization criterion. As a robust optimization algorithm was expected to be necessary for this task, genetic algorithm and particle swarm optimization algorithm have been tested, both in regular and hybrid versions. The proposed method was tested in simulations, using four power line geometries based on real-life pylons. Optimization results were juxtaposed with reference values coming from a sensor placement that would most probably be selected by a human operator when not using optimization. The proposed method offers significantly better (although still not good) conditioning of a system equation compared to reference placements. The results also provide an interesting insight into the influence of popular line geometries on numerical properties (and thus one component of uncertainty) of a contactless measurement system. Full article