最新刊期
卷 62 ， 期 9 ， 2026
- 摘要：Epoxy resin insulating parts(insulating spacers, post insulators, etc.)in gas insulated switchgear(GIS) and gas insulated transmission lines(GIL)are critical core parts of the equipment, and their long-term operational reliability faces severe challenges. Latent defects formed during the manufacturing stage(such as superficial defects, interface defects, and residual stress defects)are the main causes causing cracking, breakdown, and even rupture of insulating parts. While, the conventional factory tests, including withstand voltage partial discharge test, X-ray inspection, and hydrostatic pressure test, are severely inadequate in detecting such defects. In this paper the formation mechanisms of these three types of latent defects are systematically reviewed, with emphasis placed in the key inducing factors such as bubble nucleation, filler sedimentation, and interfacial stress mismatch. Moreover, the principles, applicability, and engineering bottlenecks of such novel non-destructive testing techniques as terahertz time-domain spectroscopy, laser ultrasound, and the acoustoelastic effect are reviewed. The research indicates that existing detection techniques have significant blind spots. Although emerging detection methods show potential, they still face challenges in terms of detection efficiency, penetration depth, and adaptability to complex structures. Future efforts should be directed toward systematic research along the main line of“mechanism clarification-detection break-through-inhibition optimization”, so as to provide theoretical support and technical pathways for improving the manufacturing quality of insulation components and the intrinsic safety of equipment.关键词：GIS/GIL;insulating spacer;latent defects;nondestructive detection1|0|0更新时间：2026-09-10
- 摘要：The objective of this paper is to propose a method for analyzing the micro-morphology characteritics after vacuum breakdown based on fractal theory. First, the micro-morphology characteritics on the rod-plane electrode surface after vacuum breakdown is obtained through the dielectric strength under lightning impulse voltage. Then, the fractal dimension of electrode surface is estimated by a structure function method and, based on the fractal dimension, the micro-morphology characteritics of electrode surface is analyzed. The results show that the fractal dimension can be used to describe the micro-morphology characteristics of electrode surface and can be estimated by the structure function method. The estimated fractal dimensions of the horizontal and vertical directions of the curved surface are basically identical, indicating that the electrode surface after the lightning impulse voltage test exhibits good isotropy. For the plane electrode, the fractal dimension of surface is affected by the breakdown energy, and has no obvious relationship with the breakdown voltage. For the rod electrode, the fractal dimension of tip surface remains consistent under different experimental conditions and the value is approximately 2.91. Therefore, the surfaces formed by vacuum breakdown under lightning impulse voltage has similar micro-morphology charactersitic, and fractal dimension can be used to describe such phenomenon.关键词：vacuum gap;surface condition;micro-morphology feature;fractal theory;dielectric strength3|0|0更新时间：2026-09-10
- 摘要：In topographically complex regions characterized by high altitude and large elevation difference, such geological activities as geothermal effects, geological subsidence, and earthquakes can substantially complicate the deformation and stress characteristics of gas-insulated metal-enclosed switchgear(GIS)and gas-insulated transmission line(GIL)and, in severe cases, induce cracking or plastic deformation, thereby threatening the safe operation of gas-insulated transmission systems. In this paper, a 550 kV GIL is taken as a case study, the basic units comprising horizontal sections, vertical shaft sections, inclined shaft sections, and elbow sections are constructed, and an integrated long-distance, high-elevation difference pipeline model is established with a vertical elevation difference of 100 m, an east-west span of 40 m, and a north-south span of 20 m. The three categories of geological activity are respectively equivalent to thermal loads, forced-deformation loads applied at pipeline-soil contact points and multi directional inertial acceleration loads. The nodal deformations are then obtained through static solutions under multiple operating conditions. The results indicate that under geothermal action the axial deformation of straight sections increases approximately linearly with temperature, reaching a maximum of 70 mm at 65℃, while the top of the inclined shaft section exhibits overstress beyond 40°C. Under geological subsidence, the axial deformation of horizontal sections remains essentially unchanged whereas the vertical deformation increases with subsidence, and the integrated model exhibits an abrupt deformation transition as subsidence increases from 15 mm to 16 mm. Under seismic action, the maximum deformation of vertical sections reaches 12.77 mm, far exceeding the 0.2 mm observed in horizontal sections, and the elbow structures demonstrate a pronounced effect in vibration mitigation and load distribution. On this basis, the optimal installation position of the bellow is investigated using the entropy weight method.The results indicate that arranging the bellow in the middle horizontal section yields better improvement under hightemperature conditions. This study reveals the differences in the deformation response patterns of GIS/GIL under various geological activities, which can provide a reference for structural design and operational safety assessment of GIS/GIL in complex terrain conditions.关键词：gas-insulated transmission line（GIL）;gas-insulated metal-enclosed switchgear（GIS）;long-distance high-drop;geological activity;deformation characteristics1|0|0更新时间：2026-09-10
- 摘要：In this paper, an experimental system for short-circuit current interruption of double-break vacuum circuit breakers is set up. Seven groups of controlled variable comparison tests are set up to systematically investigate the influence of capacitive grading and RC grading on minimum arcing time, critical arc-extinguishing gap, voltage distribution and transient characteristics across the breaker, and the transient process of asynchronous breakdown. The test results show that, compared to the case without grading mode, both capacitive and RC grading modes can effectively shorten the minimum arcing time, reduce critical arc-extinguishing gap and enhance minimum arcing interruption capability. In case of capacitive grading, increasing grading capacitance can improve voltage uniformity across open contacts, but the perfroamnce enhancement shows saturation trend. While, in case of RC grading, the interruption performance first increases and then decreases with the series resistance, reaching the optimum performance at resiatance of 40 kΩ. The transient process analysis of asynchronous breakdown indicates that R-Cgranding enables the breakdown contacts to rapidly rrecover its voltage-withstanding capability and improves the voltage distribution across open contacts, whereas neither capacitve grading nor the condition without grading exhibits such characteristics. The interruption performance of pure capacitive voltage grading is governed by the uniformity of voltage distribution, while that of RC voltage grading is determined the uniformity of voltge grading and the rapid voltage recovery following asynchronuous breakdown. The conclusion in this paper can provide theoretical support and engineering reference for grading scheme selection and parameter optimization of double-break vacuum circuit breakers.关键词：double-break vacuum circuit breaker;interruption with minimum arcing time;grading mode;minimum arcing time;critical arc-extinguishing gap2|0|0更新时间：2026-09-10
- 摘要：In this paper the arc voltage characteristics and DC performance of vacuum arcs under different magnetic field configurations are researched, and the influence patterns of various magnetic field configurations on the DC interruption capability and arc voltage evolution during arcing process are obtained. The DC interruption performance of vacuum arcs under different magnetic filed configurations is experimentally investigated. The results show that the falt-type contact subjected to a pulse transverse magnetic field exhibits the strongest DC interruption capability, achieving a maximum interruption capacity of 900V/900 A. Under the action of a pulsating transverse magnetic field, the flat contact configuration successfully achieves DC interruption at 400 V/400 A. In contrast, DC interruption capability of both the axial magnetic field contac and the spiral-groove contacts exhibit weak inferior DC interruption capabilities and are unable to interrupt DC current. The variation of arc voltage during vacuum arc interruption under diverse magnetic field configurations are compared and analyzed. The result shows that the arc voltage during DC vacuum interruption under transverse magnetic field presents severe instability and is prone to intense oscillations. Violent oscillations occur in the arc voltage of transverse magnetic field contacts throughout the arcing period. In particular, for flat contacts with externally applied transverse magnetic field under a current of 8 kA, the peak oscillation amplitude of arc voltage reaches up to 250 V.关键词：magnetic field methods;vacuum arc;DC interruption;arc voltage characteristics1|0|0更新时间：2026-09-10
- 摘要：The electromagnetic driving force of fast mechanical switches during the closing process is relatively small compared to that during the opening process, making it more susceptible to external disturbances. The longterm operation in this condition may lead to degradation or even failure of closing performance. However, the studies on the closing characteristics at present are still limited. In this paper, an in-depth experimental study is carried out on a prototype of a fast mechanical switch, investigating its closing characteristics under long-term operation from perspectives of vibration and deformation. First, a closing characteristic experimental platform is established to acquire motion, vibration, and deformation data of the switch under long-term operation. Then, the influence of capacitive voltage and friction coefficient on the closing operation is studied. The result shows that a slight decrease in the closing apactive voltage can significantly reduce the average closing speed. When the voltage drops by approximately 3%, the speed decreases by about 23%. Then, time-frequency analysis of the closing vibration signals is conducted. It is found that the vibration signals on the plane of the opening/closing coils are the most prominent, with the impulse energy primarily concentrated within the 0~5 kHz, and partcularly stronger in the 0~2 kHz range. Furthermore, both the reduction of closing capacitive voltage and the increase of friction resistance tend to diminish the spectral peak values of the vibration signals. Finally, the deformation data is analyzed in combination with stress simulation. The result shows the deformation of the link in the holding mechanism gredually increase with the number of switching operations. The degree and rate of deformation on the left side are both greater than on the right side, while the link of the actuating mechanism does not exhibit significant deformation.关键词：fast mechanical switch;closing characteristics;capacitive voltage;vibration signals;deformation characteristics1|0|0更新时间：2026-09-10
- 摘要：High-voltage circuit breakers are critical devices for control and protection in power systems. They are characterized by high voltage, large current, enclosed structures, highly transient operating processes, and difficulty in directly measuring internal states, which pose challenges to condition assessment and intelligent operation as well as maintenance. In this paper, the key technologies of digital prototype for high-voltage circuit breakers is reviewed. The key technologies of digital twins and the functional positioning of the digital prototype is firstly analyzed. Then, the digitalization requirements of high-voltage circuit breakers are summarized from such multiple physical domains as interruption, insulation, temperature rise and mechanical operation. The reconstruction requirements of internal unmeasurable states under low-intrusion sensing conditions are discussed, and the main technical challenges faced by the digital prototype are summarized in terms of real-time performance, physical interpretability and model consistency. Furthermore, real-time forward/inverse modeling, model calibration and consistency evaluation, as well as physics-data fusion modeling methods for online applications are reviewed. Finally, the development trends of the digital prototype for high-voltage circuit breakers are discussed from the perspectives of multi-source data fusion, rapid model construction, trustworthy evaluation and standardization.关键词：high-voltage circuit breaker;digital prototype;state forward prediction;parameter inverse estimation;physics-data fusion1|0|0更新时间：2026-09-10
- 摘要：Spring contact finger is critical electrical connecting element in high-voltage electrical equipment, and its performance directly affects the safety and reliability of the equipment. In this paper, the effects of wire diameter, number of spring coils, and the groove angle of the contact base on the performnce of the spring contact finger are investigated, finding that the wire diameter and the groove angle have a significant influence on the electrical contact performance of the contact finger. Increasing the wire diameter can reduce the contct resistance and current density, but may lead to localized overheating. Increasing the groove angle can reduce the contact resistance and contact temperature rise, but may result in excessively high current density. To achieve optimal performance, in this paper the NSGA-II multi-objective genetic algorithm is employed for optimization, with the minimal contact temperature rise as the objective The optimization results show that the optimal performance of the contact finger is achieved when the wire diameter is 1.5 mm, the number of spring coil is 135 and the groove angle is 135°. This study reveals the influence of tructural parameters of the spring contct finger on the electrical contact performance and proposes an optimization method based on a multi-objective genetic algorithm, providing a theoretical basis for GIL contact finger structural design and thermal fault analysis.关键词：spring-loaded contact fingers;multi-physics field coupling;contact temperature rise;structural optimisation;genetic algorithm1|0|0更新时间：2026-09-10
High-voltage Switchgear and GIS/GIL Technology
- 摘要：To reveal the key performance degradation behavior and the microscopic pyrolysis mechanism of multicomponent mixed insulating oil after lightning impulse breakdown, a lightning impulse breakdown test platform is established. The physicochemical properties, dielectric performance, and dissolved gas content of the oil samples are tested under different oil-gap conditions. Furthermore, molecular dynamics simulations based on the ReaxFF reactive force field are conducted to analyze the pyrolysis pathways of oil molecules and the formation mechanisms of characteristic gases under the coupled effects of high-temperature and strong electric field generated by the breakdown discharge. The results show that with increase of oil gap, the performance degradation of the oil samples after breakdown becomes more severepronounced. Among all parameters, the acid value exhibits the most significant increase, rising by nearly 190% compared to the initial value under long-gap conditions, which can serve as a sensitive indicator of impulse aging degree. Under long-gap conditions, the dielectric dissipation factor and volume resis tivity deteriorate by approximately 53% and 40%, respectively, while the particle concentration increases significantly and is mainly distributed in the 5~15 μm size range. The H2 and C2H2 are identified as the main characteristic gases, and their contents increase continuously with increase of discharge energy. The molecular simulation indicates that under a low electric field, pyrolysis is dominated by stepwise single-bond scission, while a strong electric field accelerates the pyrolysis process by enhancing molecular polarization and increasing the probability of chemical bond cleavage, and also induces ring-opening reactions of aromatic hydrocarbons. However, the formation pathways of characteristic gases still follow conventional thermal pyrolysis mechanisms. The study results can provide a theoretical basis for the engineering application and insulation condition assessment of multi-component mixed insulating oil.关键词：multi-component mixed insulating oil;lightning impulse;gas generation characteristics;pyrolysis mechanism;reactive molecular dynamics;dielectric performance;transformer;performance evolution1|0|0更新时间：2026-09-10
- 摘要：X-ray-assisted partial discharge detection can provide initial electrons through radiation ionization, thereby reducing the statistical time lag of discharges at microscopic defects and enhancing excitation and detection probability of concealed defects. In view of the ambiguity regarding radiation-induced secondary charge particle source terms under the multi-media coexistance condition of metals, gas and solid insulation within GIS, a full-scale GIS particle transport model incorporating SF6 gas, central conductor, metal enclosure, metal inserts, and epoxy insulators is developed using Geant4 in this study. Monte Carlo transport calculation is performed for incident photons and energies of 100 keV, 1 MeV, 5 MeV, and 10 MeV. By statically analyzing the statistical energy deposition, γ-photon interaction processes, generation channels of secondary electron and positron productio, as well as the spatial distribution of charged particles, the formation characteristics of the pre-ionization sources terms and their spatial correlation with potential discharge-sensitive regions are investigated. The results indicate that 100 keV photons are primarily shielded and constrained by the metal enclosure at the incident end, with secondary electrons exhibiting a short secondary range, and the pre-ionization sources terms being mainly concentrated near the enclosure and and metal inserts. At 1 MeV, Compton scattering accounts for 89.84% of the interactions, and the distribution of secondary electrons extends toward the central conductor, insulator and the regions adjacent to gas gaps. Under the GIS geometric model and incident direction conditions adopted in this paper, 5~10 MeV photons render the vinicity of the central conductor the primary region for energy deposition and interactions, where electron-positron pair production also occurs.The study results can provide source-term references for parameters selection in X-ray-assisted GIS defect detection and fo radiation-discharge coupled modeling.关键词：GIS;X-rays;Geant4;SF6;Compton scattering;secondary electrons;energy deposition1|0|0更新时间：2026-09-10
- 摘要：The main insulation, inter-winding layer insulation and insulation near winding conductors of power transformers are all oil-pressboard insulation structures. However, due to differences in pressboard layer thickness, the number of oil-pressboard interfaces and the distribution of copper foil conductor layers, the partial discharge characteristics exhibit significant variations. To analyze the influence of structural differences on AC partial discharge under similar insulation thicknesses, the samples of single-layer thick oil-pressboard, multi-layer thin oilpressboard and copper foil-multilayer thin oil-pressboard are prepared. The partial discharge inception voltage (PDIV)is measured using the pulse current method in a needle-plate electrode model, the phase-resolved partial discharge and time-resolved partial discharge patterns are obtained, and the discharge repetition rate and average discharge magnitude are calculated. The results show that the PDIV of the three samples are 5.73 kV, 8.42 kV and 10.19 kV, respectively. After voltage application for 120 minutes, the multi-layer thin oil-pressboard sample has the highest discharge repetition rate, approximately 82 times/s, while the copper foil-multilayer thin oil-pressboard sample has the highest average discharge magnitude, approximately 199 pC. Multi-layer interfaces increase the discharge repetition rate, while the copper foil layer enhances the discharge intensity. The discharge development status shall be assessed by combining discharge patterns with statistical features.关键词：power transformer;oil-pressboard insulation;needle-plate electrode;partial discharge characteristics1|0|0更新时间：2026-09-10
- 摘要：Temperature modulation technology can significantly improve the selectivity of metal oxide semiconductor gas sensors and enhance their identification capability. However, existing methods inadequately utilize the structured dynamic response information formed by the synergistic interplay between the temperature modulation process and gas adsorption-reaction kinetics. Moreover, the interpretability of their prediction processes remains limited. To address these limitations, in this paper a gas mixture concentration prediction method based on a sensor-period attention mechanism is proposed. By modeling the response evolution patterns along the modulation-period dimension and characterizing multi-channel interaction relationships across the sensor channel dimension, a lernable importance weighting mechanism is employed to fuse critical sensor-period features, thereby enabling joint prediction of gas mixture concentrations. Experimental results targeting the gases released from the abalation of the cable buffer layer demonstrate that the proposed method achieves superior prediction performance compared to the selected benchamark models, with a coefficient of determination of 0.99 for concentration prediction. Furthermore, the method is capable of revealing the contributions of different temporal responses to the prediction results, thereby providing an interpretable basis for dynamic responses analysis of gas mixture.关键词：gas sensor array;temperature modulation;interpretability analysis;gas concentration identification;attention mechanism;metal oxide semiconductor sensor0|0|0更新时间：2026-09-10
- 摘要：Dielectric barrier discharge(DBD)can stably generate various reactive species in the air and is widely used in such fields as energy conversion, environmental management, and biomedicine. An ideal excitation power supply for air DBD shall achieve stable control of discharge parameters, and possess high reactive species generation and energy efficiency. In this paper, a high-voltage sinusoidal power supply with superimposed high-frequency oscillation is designed. By controlling the on-off of the switching tube in the oscillation unit, an LC parallel resonance is generated, which is superimposed with the high-voltage sinusoidal wave produced by the inverter unit, achieving an output of high-voltage sinusoidal wave with high-frequency oscillation superimposed at the wave peaks. Experimental tests show that the peak-to-peak value of sinusoidal wave output by the high voltage sinusoidal power supply prototype with superimposed high frequency oscillation is about 4 kV, the frequency is about 5 kHz, the oscillation amplitude is around 2 kV and a frequency is up to 300 kHz. Under identical power conditions, the use of this power supply for exciting air dielectric barrier discharge produces a great amount of short-lived reactive species and a higher nitrogen oxide yield than a conventional sinusoidal power supply, thereby promoting the discharge conversion toward the nitrogen oxide mode.关键词：dielectric barrier discharge;high-frequency oscillation;high-voltage sinusoidal power supply;reactive species;discharge mode1|0|0更新时间：2026-09-10
- 摘要：In view of the issue that the traditional frequency domain spectroscopy(FDS)analysis is based on the assumption of uniform moisture ingress, which make it difficult to accurately reflect the non-uniform moisture distribution actually existed in oil paper insulated bushings, a dielectric response analysis method for non-uniform moisture ingress is proposed based on the combination of inite element simulation with experimental validation. A dual-unit stacked FDS simulation model is established using Comsol, along with uniform and non-uniform moisture distribution models for the bushing. The effects of moisture content and its spatial distribution on the dielectric response are systematically analyzed. The results indicate that non-uniform moisture induces distinct loss peaks and fluctuation characteristics in the tanδ-f curves. The greater the degree of non-uniformity, the higher the frequencies of the loss peak and th curve intersection point, indicating that the dielectric response is relatively sensitive to localized moisture end screen. Both simulations and experiments are in good agreement, which provides a new technical means for identifying and quantitatively assessing non-uniform moisture distribution in oil-paper insulation, and is of great significance for advancing accurate insulation diagnosis of power equipment.关键词：oil-paper insulation;non-uniform moisture;frequency domain spectroscopy（FDS）;finite element analysis;bushing;moisture;permittivity;condition assessment1|0|0更新时间：2026-09-10
Research on Insulation Medium and Discharge Mechanisms
- 摘要：In view of the issues that the unbalanced protection of filter capacitor towers in converter stations of highvoltage direct current(HVDC)transmission systems is susceptible to bird-related disturbance, and that traditional physical bird-deterrent measures lack long-term effectiveness, in this paper the fault mechanism and identification methods of bird-related disturbance are investigated so as to enhance the operational reliability of protection system under complex environmental conditions. The differences in the generation echanism between internal faults within the capacitor towers and transient bird-related faults are analyzed. Based on frequency-domain analysis of fault waveform characteristics, key frequency-domain indicators that can effectively distinguish between the two types of faults are extracted. An electromagnetic simulation model of the capacitor tower that is consistent with actual operating conditions is established, revealing the overload characteritics and withstand limits of capacitor units durign fault process. On this basis, a targeted improvement strategy for unbalanced protection is proposed. The deficiency of the existing protection in riding through transient bird-related disturbance process is addressed by refining the fault discrimination algorithm and the trip delay logic. Both simulation and test results demonstrate that the proposed strategy can significantly suppress protection maloperations caused by bird activities while maintaining a rapid response to internal faults. This research offers both conceptual guidance and a technical basis for enhancing the reliable performance of unbalanced protection for converter station capacitor towers in complex operating environments.关键词：filter capacitor towers;unbalanced protection;bird-related faults;frequency-domain characteristics;optimization strategy1|0|0更新时间：2026-09-10
- 摘要：Due to global climate change, the superposition of high temperature, low humidity and extreme weather conditions has led to a manifold increase in both the risk of wildfires and the area burned. In recent years, the frequent occurrence of wildfires has become a major global disaster, exerting far-reaching impacts across multiple dimensions, including casualties, property losses, ecological environments and social governance. Statistical data indicate that faults in distribution lines have emerged as a critical trigger for wildfires, exhibiting severe destructive potential and accounting for the most substantial damages. To clarify the disaster-inducing process of tree-line faults in forest distribution lines and to support wildfire risk prevention and control, in this paper a comprehensive review of tree-line faults in forest distribution lines is presented from the perspective of such four key aspects as evolutionary mechanism of tree-line faults, fault detection and identification, risk prediction, and wildfire ignition. First, the formation mechanism of tree-line faults in forest distribution lines is analyzed, revealing that such faults sequentially undergoes such three stages as contact conduction, carbonization arcing and fire ignition-induced disaster.This is a progressive hazard process driven by thermo-electrical-chemical coupling effects. Then, based on the research of above mechanism, such four categories of tree-line fault detection technologies as electrical waveform detection, partial discharge monitoring, magnetic field sensing and multi-modal fusion detection are analyzed. After that, the differentiated application characteristics of statistical models, data-driven models and forecasting algorithms for datascarce scenarios are systematically summarized. Finally, an assessment of the widlfire risk caused by such faults is conducted by integrating multiple categories of influencing factors, and corresponding preventive measures are summarized and prospected. In the future, leveraging technological means such as satellite remote sensing, unmanned aerial vehicle(UAV)patrol inspection and 3D laser LiDAR scanning are used to monitor and integrate multi-source fire hazard factors, including meteorologys, vegetation, power line status and terrain, enable dynamic, quantitative and refined wildfire risk assessment of wildfire risks, as well as spatiotemporal risk deduction and simulation, representing a critical technical direction for technology-empowered disaster relief, migigation and prevention.关键词：forest distribution lines;tree-line fault;wildfire risk;fault detection;risk assessment1|0|0更新时间：2026-09-10
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Inter-turn Short Circuit Prediction of Reactors Under Lightning Impulse Based on Stacked Autoencoder
摘要：Existing research on the causes analysis of inter-turn short-circuit faults in dry-type air-core reactors primarily focuses on manufacturing defects and long-term aging, while lacking quantitative analysis and fault tracing methods specifically for the trigger of lightning impulse. In this paper the ±800 kV dry-type air-core reactors are taken as the subject of study. First, the inter-turn voltage distribution of reactor winding under lightning impulse conditions is revealed by using the multi-conductor transmission line theory and high-frequency distributed parameter models , along with Ansys electromagnetic simulation and Simulink wave process analysis. The stacked autoencoder is combined with Gaussian processes(SAE-GP)in this paper for rapid prediction of inter-turn voltage distribution of dry type air-core reactor under lightning impulse condition. Compared with existing linear dimensionality reduction methods based on principal component analysis and single-layer autoencoders, the SAE-GP model can effectively capture nonlinear spatial features in inter-turn voltage distributions through its deep stacking structure, achieving higher prediction accuracy and fault localization precision even under small sample conditions. Finally, taking a lightning strike incident at a converter station in Zhejiang province as a case study, the fault recorder data is utilized to verify the practicality of the proposed method in fault tracing, which provides theoretical basis and technical support for lightning inpulse fault tracing and active early warning of dry-type air-core reactors.关键词：dry type air-core reactor;distribution parameters;voltage distribution;inter-turn short circuit;lightning waveform parameters;stacked autoencoder;Gaussian process;orthogonal experiment1|0|0更新时间：2026-09-10 - 摘要：Converter transformer is a critical component of high-voltage direct-current(HVDC)transmission systems, and its fault evolution exhibits nonlinear and strongly coupled characteristics. To address the problems of underutilized operation and maintenance text data and the lack of interpretability in the diagnostic process, an interpretable knowledge graph reasoning method(IKGR)is proposed. First, an ALBERT-BiLSTM-CRF model is adopted to extract entities from such unstructured text as maintenance records and fault reports. The relational triples are organized in accordance with the schema layer of the knowledge graph and physical causal constraints, thereby constructing a converter transformer fault traceability knowledge graph. Then, a dual-agent reinforcement learning reasoning model is designed, in which a soft reward mechanism is introduced and a short-term on-policy trajectory buffer is utilized to synchronously update the parameters of the dual agents, thereby achieving multi-hop fault traceability. Experimental results show that IKGR achieves 94.8% in terms of the root cause ranking meric Hits@10, and is capable of generating reasoning paths comprising equipment components, fault status, protective actions and testing methods, thereby providing path-level explanations for converter transformer fault handling and O & M decision-making.关键词：converter transformer;fault traceability;knowledge graph;dual-agent reinforcement learning;interpretable artificial intelligence1|0|0更新时间：2026-09-10
- 摘要：To address the challenges of the difficulty in field measurement of the global transient magnetic field during no-load closing operation of transformer, the low computational efficiency of traditional finite element analysis, and the insufficient prediction accuracy of single models, a dataset comprising 560 valid samples with coverage of seven closing-angle conditions is constructed through finite element simulations. The random forest algorithm is employed to perform feature importance screening, and principal component analysis is utilized to compress the 10418dimensional magnetic field data to 300 dimensions. A CNN-Transformer hybrid prediction model is then established, where one-dimensional convolution is used to extract local transient features of the inrush current and the multi-head attention mechanism is adopted to capture global temporal dependencies, thereby enabling end-to-end rapid reconstruction of the global transient magnetic field. Experimental results show that the average absolute error of the model is as low as 0.0042 T, the average absolute percentage error is 0.42%, and a coefficient of determination(R2)of is 0.987. The prediction time per sample is 4.5 ms, which is more than 105 times faster than traditional finite element methods. Under extreme conditions, the global average absolute error is 0.0032 T, with the maximum error not exceeding 0.01 T. The coefficient of determination under all operating conditions is not less than 0.982. The proposed model exhibits high prediction accuracy, strong generalization capability, and high computational effi ciency. It can effectively achieve fast and accurate prediction of the transient magnetic field during transformer inrush current, providing technical support for condition assessment and protection setting of transformer.关键词：transformer;excitation inrush;transient magnetic field prediction;CNN-Transformer;principal component analysis1|0|0更新时间：2026-09-10
Technology for Fault Identification, Prediction and Protection of Power Equipment
- 摘要：To address the increasingly prominent issue of high-frequency noise generated by nanocrystalline medium-frequency transformers under non-sinusoidal excitation, and the fact that the overall vibration sources and noisec characteristics of the transformer remains unclear, in this paper the vibration measurements on the transformer core, windings, and clamping plates is carried out under both no-load and short-circuit conditions. The primary vibration sources and their transmission characteristics are identified. Furthermore, by measuring the sound pressure levels at the top surface and four side surfaces of the transformer under different voltage excitations, the major noiseradiating surfaces are determined, and the effects of excitation voltages on noise levels and spectral characteristics are analyzed. The research results show that in case of no load and short ciruit conditions the vibration amplitude of the transformer core is significantly higher than that of the windings and clamping plate, indicating that the core is the dominant vibration source. The vibrations are transmitted to the windings and clamping plate through structural coupling. In addition to the core, the windings and clamping plate are also important noise-radiating positions, where core vibrations induce structural vibrations and subsequent noise radiation through mechanical coupling. Moreover, the uneven distribution of local clamping pressure is the primary cause of the fundamental-frequency component observed in the vibration and noise signals.关键词：medium-frequency transformer;non-sinusoidal excitation;vibration source;noise characteristics1|0|0更新时间：2026-09-10
- 摘要：The thyristor-controlled phase shifter exhibits complex magnetic circuit coupling and, in case of system fault, the electromagnetic force impulse poses a major threat to the reliability of its windings. Based on the electromagnetic transient characteristics analysis of the phase shifter windings under typical external faults, in this paper an electromagnetic force calculation model for the phase shifter windings is setablished, the leakage magnetic field and electromagnetic force distribution characteristics of the phase shifter under fault conditions is investigated, and the effects of the parallel transformer tap position and winding arrangement sequence on the electromagnetic force distribution charcateristics are analyzed. The results show that for the series transformer, under the grid-side single-phase grounding fault of the parallel transformer, the maximum radial and axial electromagnetic forces appear at about 1/5 and 1/2 of the winding, reaching 587.8 kN and 994.8 kN respectively. In case of single-phase grounding fault on the external line, the maximum radial and axial electromagnetic forces appear at about 1/2 of the winding and the end of the winding, reaching 441.5 kN and 938.9 kN respectively. The electromagnetic forces maintain a large value within several cycles after the fault occurrence and decay synchronously with the current.For the parallel transformer, the electromagnetic force distribution is similar under the two fault conditions. The maximum values of the radial and axial electromagnetic forces appear at 1/3~1/2 of the winding and the end of the winding, respectively. The electromag netic force is concentrated in the first cycle after the occurrence of fault. Variations in the phase shifter's tap position and differences in the winding sequence of the parallel transformer both alter the leakage magnetic field distribution, thereby affecting the electromagnetic forces. Change in the tap position can result in a maximum electromagnetic force difference of up to 14 kN, while optimizing the winding arrangement sequence can reduce the maximum electromagnetic forec eby nearly 50%. The research in this paper provides a reference for optimizing phase shifter structures and has important guiding significance for engineering applications.关键词：thyristor controlled phase shifters;typical faults;electromagnetic force distribution;finite element method1|0|0更新时间：2026-09-10
- 摘要：In this paper a calculation method for determining calble temperature rise based on the similarity principle is presented. By leveraging heat transfer principles such as similarity theory and gas radiation charcateristics, the convective and radiative componsnes involved in the calculation of tunnel calbe temperature rise are relatively decoupled from each other. Through proportional scaling, the convective heat transfer characteristics of the fullscale model are represented by those obtained from a small-scale model. Combined with the determination of the radiative heat tranfer coefficient, a system of implict equations characterizing the temperature rise behavior of the tunnel cable group is established. By transforming the field simulation into the solution of this equation system, rapid cable temperature rise calculation is achieved with relatively low computional resources. Validation through case studies demonstrates that the proposed method is reliable with controllable errors, significantly improving both computional accuracy and efficiency.关键词：similarity principle;tunnel cables;temperature rise1|0|0更新时间：2026-09-10
- 摘要：Junction temperature is a critical factor affecting the long-term operational reliability of thyristors, and its rapid and accurate calculation is essential for assessing such reliability. Therefore, in this paper the relationship between thermal resistance from the thyristor junction to coolant and water flow rate is analyzed based on the parallel cooling circuit structure of thyristor converter valves, and a junction temperature calculation method for thyristors at all levels of valve assemblies that accounts for branch length variations in parallel cooling circuits is proposed. First, the relationship between thermal resistance from thyristor to coolant and cooling water flow rate is obtained through structural analysis of thyristors and heat sinks. Then, considering the parallel cooling water circuit structure, water flow distribution across different valve assembly levels is analyzed. Moreover, an iterative junction temperature calculation model is developed in combination with thermal resistance and flow characteristics. Finally, the junction temperature calculation is validated using data from an actual converter station, and the accuracy of the proposed method is verified through both equivalent circuit simulation and finite-element simulation.关键词：thyristor;parallel water circuit;thermal resistance;junction temperature calculation1|0|0更新时间：2026-09-10
Simulation and Analysis of Thermal and Electromagnetic Characteristics of Power Equipment
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