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15 October 2025, Volume 44 Issue 10 Previous Issue   

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Research status of early warning and monitoring technology for electrical fire Ma Li, Jiang Huiling, Li Yang, Liu Shulin, Xu Yang4, Huang Xiao, Yan XiaoQing 2025, 44 (10):  1441-1450.  Abstract ( 86 )   Electrical fire monitoring and early warning are of great significance for fire prevention and control. In response to the complexity of early signs and the limited accuracy of risk prediction, this paper analyzes the research progress on the coupled mechanisms of multiple electrical faults which may lead to electrical fires, including overheating, short circuits, arc faults, overloads, and glowing connections, further compares fault identification methods and models, and provides a systematic review of the state-of-the-art in electrical fire monitoring and early warning technologies. The review highlights the critical scientific issues and technical challenges from the viewpoints of failure mechanisms, monitoring and identification technologies, and early warning systems. It is proposed to carry out experiments on reproducing disaster scenarios involving the transformation between different electrical faults, thereby identifying characteristic parameters of early warning signs associated with primary fault sources of electrical fires. Furthermore, a predictive model for overheating risk in electrical circuits was developed by integrating multi-source information, including electrical parameters, pyrolysis gases, and environmental factors, enabling accurate early-stage warning of overheating conditions. Multi-source recognition and localization approach for glowing connections that integrates electrical, thermal, gaseous, and optical signals was developed, and a monitoring strategy for fault arcs under multi-factor coupling conditions was proposed. Research on an intelligent monitoring and early warning system for electrical fire hazards based on cloud-edge-device collaboration, the construction of an electrical fault disaster spectrum, and AI-powered electrical fire early warning agents are key trends in improving the accuracy of monitoring and early warning. Related Articles | Metrics

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Study on the influence of overcurrent and poor contact on temperature rise characteristics of household single-phase socket plug Wang Weifeng, Dong Mengyang, Ji Xiaohan, Liu Yixiang, Zhao Jingyu, 2025, 44 (10):  1451-1456.  Abstract ( 33 )   As one of the most frequently used components in household power distribution systems, socket plugs are highly susceptible to thermal failure caused by overcurrent and poor contact faults, which are major contributors to residential electrical fires. In this study, household single-phase socket plugs with rated currents of 10 A and 16 A were selected. An experimental circuit was constructed using 2.5 mm² BV single-core copper wires and 1.5 mm² BRV multi-core copper wires to simulate two typical fault scenarios: overcurrent and poor contact. Infrared thermography and a fault simulation platform were employed to systematically investigate the temperature rise characteristics and thermal failure behavior under different fault conditions.Results show that when the current exceeds four times the rated value, accompanied by melting, carbonization, and breakage of conductors and insulation, the fire risk is significantly increased. When the contact resistance increases to 100 Ω, even under moderate current, the temperature can exceed 180 °C. If current and resistance rise simultaneously, the peak temperature may surpass 350 °C, forming a thermal runaway positive feedback mechanism. Repeated overload tests also indicate that cumulative thermal fatigue intensifies with the number of cycles, accelerating the occurrence of thermal damage and ignition.This study clarifies the critical temperature thresholds and fire-triggering mechanisms of socket plugs under typical electrical fault conditions, providing important theoretical and experimental references for the structural design, safety evaluation, and fire warning of household electrical accessories. Related Articles | Metrics

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The impact of slight overcurrent on the pyrolysis and insulation impedance of BVVB sheathed wires Sheng Yawen, Han Yun, Guo Xinyao, Li Yang, Wei Zhen 2025, 44 (10):  1457-1464.  Abstract ( 30 )   Wire overheating fault is one of the prevalent intrinsic fault types in electrical circuits, typically triggered by overcurrent, which can induce thermal decomposition and carbonization of insulating materials, thereby precipitating faults such as short-circuit breakdown, open-circuit. Previous studies have predominantly focused on the thermal decomposition characteristics and breakdown behaviors of sheathed wires under high overcurrent conditions, while research on the impact of slight temperature increases on the microscopic physicochemical properties of insulating materials under slight overcurrent conditions is insufficient. In this study, BVVB polyvinyl chloride-insulated copper conductors were selected as the research subject. Slight overcurrent samples were prepared utilizing a self-developed electrical fault simulation experimental setup, and then the relationship between the changes in insulation performance and their microscopic physical and chemical structures under slight overcurrent was analyzed using insulation resistance tester, synchronous thermal analyzer, Fourier transform infrared spectrometers (FTIR) and field emission scanning electron microscopes (FESEM). The results indicate that the short-term overcurrent does not rapidly deteriorate the insulation performance; instead, it enhances the electrical insulation performance in stages. The results of TG, FTIR, and FESEM prove that this phenomenon is due to the formation of conjugated polyene structures. This study demonstrates that slight overcurrent can progressively improve the insulation performance of wires over a short duration. By measuring the changes in the insulation impedance of the wire in a timely manner, it is possible to detect electrical fires earlier and promptly mitigate potential electrical fire risks. Related Articles | Metrics

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Study on the heating ignition law and melting marks characteristics in local strand breakage of multi-strand copper wires Wang Qiang, LinYixuan , Sheng Yawen, Li Yang, Gong Jian 2025, 44 (10):  1465-1470.  Abstract ( 28 )   Mechanical damage such as animal gnawing and squeezing may cause partial loss of insulation layer and core of the wire, resulting in increased local resistance and heating, leading to electrical fires. A specialized electrical fire fault simulation platform was established, to systematically conduct research on heating and ignition. The resistance increment is controlled by cutting the ZR-BVR multi-strand copper wire core by core. The representative combustible material was powdered pine wood. Infrared thermography, high-speed videography, and metallographic microscopy were used to analyze the thermal behavior, ignition boundaries, and morphology of melting marks. The results indicate that two necessary conditions must be met for ignition at defective wire sections: sufficient release of flammable pyrolysis gases from the combustible material, and the formation of a breaking arc upon wire fusing. Excessive or insufficient defect severity failed to trigger ignition. Combustion occurred primarily under the conditions of 2 strands at 2 cm, 4 strands at 8~10 cm, and 5 strands at 10 cm. Melt mark morphology was correlated with electrode polarity: spherical at the anode and pointed at the cathode. When ignition occurred, the metallographic structure exhibited equiaxed crystals, large pores, and indistinct transition zones. Without ignition, the structure appeared as fine dendrites with well-defined grain boundaries. Local strand defects in energized copper wires pose a significant potential fire risk. Accurate localization of defects, combined with microstructural analysis of melting marks, can provide robust evidence for determining fire causation and fault attribution in electrical fire investigations. Related Articles | Metrics

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Research on the impact of AC series fault arcs on the electrical characteristics of upper and lower stages in low-voltage distribution systems Ye Yanchao, Jiang Huiling, Deng Qing 2025, 44 (10):  1471-1478.  Abstract ( 57 )   In the field of fire safety, electrical fire hazards are prominent and have become a major hidden danger threatening the safety of life and property. Existing research has insufficiently explored the linkage between series fault arcs and the electrical characteristics of upper and lower distribution systems. To address this current situation, guided by the practical needs in the field of fire safety, this paper focuses on low-voltage distribution systems, builds an experimental platform for AC series fault arcs, sets 10 operating conditions with 3 repetitions for each group, and collects electrical signals of fault arcs as well as upper and lower distribution systems. Through preprocessing the experimental data, combined with methods such as waveform analysis, cosine similarity calculation and analysis of variance, an in-depth analysis is conducted on the time-domain characteristics of the electrical properties of fault arcs, upper distribution system and lower distribution system. The research shows that: the fault duration at the arc point is the longest, followed by the upper distribution system, and the lower distribution system has the shortest; the current kurtosis of the fault arc and upper and lower distribution systems all fluctuates between 1.1 and 1.9, generally ranging from 1.5 to 1.8, which is classified as platykurtic; there is a significant difference in voltage kurtosis among the fault arc, upper distribution system and lower distribution system, and the voltage kurtosis of the fault arc is significantly higher than that of the upper and lower distribution systems; the current impulse factor of the lower distribution system is generally higher than that of the upper distribution system, and both are higher than that of the fault arc point, indicating that the transient current impact caused by the fault arc is more significant in the lower system; the voltage impact of the fault arc is significantly higher than that of the upper and lower distribution systems, showing greater volatility and uncertainty, while the voltage of the upper and lower distribution systems is relatively stable. By capturing the differences in electrical parameters between fault arcs and low-voltage distribution systems and integrating these differential characteristics into the electrical fire monitoring system, the identification accuracy and response speed of the system to fault arcs can be improved, which is helpful for optimizing the fault arc detection devices of low-voltage distribution systems and constructing a fire risk prevention and control system for low-voltage AC distribution systems. Related Articles | Metrics

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Dynamic change of luminous connection caused by poor contact of distribution box Wang Lin, Ge Dahui, Zhao Yanhong, Li Yang 2025, 44 (10):  1479-1485.  Abstract ( 22 )   In order to explore the phenomenon of luminous connection caused by poor contact of terminal zero of distribution box and its temperature rise law, an experimental platform was built to simulate the poor contact state, and the temperature rise experiments of terminal-conductor system under different current and torque conditions were carried out systematically, revealing the temperature change characteristics and the macro-morphological evolution mechanism of conductor during luminous connection. By controlling the current and tightening torque to simulate different degrees of poor contact, the temperature rise process and apparent changes were observed and recorded. The results show that the temperature rise after the formation of luminescent connection can be divided into two typical stages, and the macro-change characteristics of the conductor are consistent under different conditions. Poor contact and current significantly affect the degree of heating: poor contact can lead to luminous connection at a small current, while the temperature rises sharply at a large current, which significantly increases the fire risk, and the electrical protection device often fails to act in time under such faults, further increasing the fire risk. This study clarifies the core characteristics and risk mechanism of terminal heating caused by poor contact, which provides experimental and theoretical support for fire warning and safety protection of distribution box system, and is of great value to improve the monitoring and prevention ability of poor contact faults in the design and maintenance of distribution system, and lays the foundation for the subsequent research on luminous connection under multivariable coupling conditions. Related Articles | Metrics

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Study on the evolution characteristics of carbonized channel in tree-contact single-phase-to-ground fault of distribution network conductor Zhou Yao, He Jianbo, Liu Mingxian, Shen Xueming, Li Ziping, Ning Wenjun 2025, 44 (10):  1486-1494.  Abstract ( 18 )   The height of the distribution network line is low, and the surrounding trees are easy to lap up with the line to form a Tree-contact Single-phase-to-ground Fault (TSF), which can lead to fire in severe cases. An important feature of TSF is the formation and development of charring channels on the surface of branches. Observing the morphology of the carbonization channel can qualitatively judge the fault process, but it still lacks a quantitative relationship corresponding to the electrical characteristic quantities of TSF. Based on this, this paper simulated TSF on a 10 kV experimental line, and studied the leakage current, combustion image and temperature distribution in the whole development process of TSF by means of electrical parameter measurement, high-speed camera and infrared temperature measurement, and established the correlation between the qualitative characteristics of carbonization channel development form and the quantitative parameters of leakage current. The results show that the TSF can be divided into five stages according to the leakage current development characteristics: the initial development stage of the carbonization channel, the horizontal development stage, the vertical development stage, the suppression stage and the ignition/stop stage. Combined with the current waveform and high-speed camera image, the development form and cause of the carbonization channel in each stage were analyzed in detail. The results show that there is a stage correlation between the change trend of the leakage current and the development process of the carbonization channel. The resistance U-shaped curve in the fault process was analyzed, and the main cause came from the time difference between the development of the carbonization channel and the water evaporation. The research results can provide theoretical reference for the identification and monitoring of TSF. Related Articles | Metrics

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Research on the identification method of over-temperature three inducements of electrical circuits based on ReGAT-ResNet Li Li, Wang Haozhou, Pan Hongguang, Shi Keke 2025, 44 (10):  1495-1501.  Abstract ( 25 )   When abnormal conditions such as overload, harmonics, and non-periodic currents occur in electrical circuits, they can easily cause abnormal temperature rises, which may lead to electrical fires. Rapid and accurate identification of these over-temperature causes is crucial for improving the accuracy of fire warning systems and ensuring fire safety. This paper proposes an over-temperature cause identification method for electrical circuits based on Recurrence Graph-Graph Attention Network and Residual Network (ReGAT-ResNet). By leveraging the temporal dependencies of current signals under over-temperature conditions, the method maps them into high-dimensional trajectories through phase space reconstruction, and extracts temporal dynamic structural features using recurrence plot techniques. A graph neural network is then employed to model the graph-structured data, and a three-layer Graph Attention Network (GAT) is constructed. The introduction of a residual connection mechanism enhances the stable propagation and fusion of deep features, while global average pooling and a fully connected layer are used for classification prediction. The method is validated and analyzed using experimental datasets under different operating conditions involving overload, harmonics, and non-periodic currents. Experimental results show that the proposed model achieves an identification accuracy of 99.57%, can provide an effective technical foundation for early warning and fire risk prevention in electrical systems. Related Articles | Metrics

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Simulation analysis of temperature field of five-core cable under overload and DC component effects Pan Hongguang, Zhang Yi, He Rong, Wang Yuntao 2025, 44 (10):  1502-1509.  Abstract ( 17 )   Overload and direct current (DC) components increase the effective value of the conductor current. When the effective current exceeds the maximum current-carrying capacity, additional losses occur, leading to temperature rise and even electrical fires. To address the insufficient research on temperature field evolution and fire risk assessment of multi-core cables under overload and DC components, this study develops an electromagnetic-thermal coupling model of the WDZ-YJY (4×50+1×25) five-core cable using COMSOL Multiphysics, to simulate the temperature field under different overload levels and DC components. The results show that under normal operation, the core temperature is 61.61 ℃. As the overload factor increases, the core temperature rises and gradually approaches a steady state. At 1.3 times overload, the maximum core temperature reaches 90.35 ℃. When the DC component increases from 1% to 10%, the core temperature shows a slight upward trend, reaching 64.56 ℃ at 10%. Overload causes a significant temperature rise, and once it exceeds the safety limit of 90 ℃, it accelerates insulation aging and triggers potential fire hazards. The thermal effect of DC components is relatively weaker than overload, but high DC levels still lead to notable temperature increases. This study provides a basis for evaluating cable operational status, supports thermal risk identification and alarm threshold setting in early fire monitoring systems, and enhances the assessment and early warning of multi-core cables under complex operating conditions. Related Articles | Metrics

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Research on temperature rise prediction of single-core cables considering harmonic and overload inducing factors Li Xiaoyan, Liu Shulin, Zhao Yongxiu, Sun Longjie 2025, 44 (10):  1510-1516.  Abstract ( 20 )   Most existing temperature prediction methods focus on a single cause and ignore the influence of the coupling effect of combined harmonic and overload on the temperature rise of cables, resulting in large prediction errors. This paper takes low-voltage single-core cables as the research object, and based on Fourier's law and the law of conservation of energy, constructs a transient thermal equilibrium equation under overload causes; Introduces the skin effect to correct the resistance and constructs a transient thermal equilibrium equation under harmonic causes; By coupling the equations of the two causes, determines the boundary conditions, and establishes a transient thermal equilibrium mathematical model integrating harmonics and overload. The model is numerically solved by the finite difference method, and the temperature evolution trends of overload, harmonics, and the combination of the two are deeply analyzed. The results are verified by COMSOL simulation. The results show that the steady-state temperature of the cable has a nonlinear growth relationship with the overload multiple; when the content of each harmonic is constant, as higher harmonics are superimposed, the amplitude of the cable temperature rise gradually decreases; the error between the numerical results and the simulation results is within 1 ℃, verifying the correctness of the model. Related Articles | Metrics

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Temperature prediction of low-voltage five-core cables during electromagnetic-thermal coupled overload operation Zhao Yongxiu, Fang Jiachang, Kong Linghao, Liu Shulin 2025, 44 (10):  1517-1523.  Abstract ( 23 )   For the prediction of overload temperatures in low-voltage five-core cables, traditional thermal-network models suffer from accuracy degradation due to multiphase heat‐source coupling, geometric nonuniformity, and the temperature dependence of resistance. To address these shortcomings, this paper develops a two-dimensional, transient temperature-field finite‐element model based on electromagnetic-thermal coupling. Taking YJV 5.0×2.5 mm² low-voltage cable as the study object, the coupled Maxwell and transient heat‐conduction equations are solved via a Galerkin weak‐form discretization and an implicit Euler time‐integration scheme to obtain cable‐temperature evolution under various operating conditions. The results indicate that under balanced three-phase loading, the B-phase core constitutes the highest‐risk zone for insulation failure; when ambient temperature rises from 15 °C to 40 °C, the steady-state core temperature increases by 27.53 °C, corresponding to an 18.68% loss increment. With load current elevated from 15 A to 35 A, steady-state core temperature rises by 81.1 °C, with losses increasing by 37.18%. Experimental validation shows that the model predicts outer-sheath temperature with a mean absolute error below 3%, and that a 3 600 s transient simulation completes within 5 min. The proposed model overcomes the simplifications inherent in traditional methods for multiphysics coupling and can be applied to electrical‐fire hazard assessment and overheat warnings, providing theoretical support for dynamic current‐carrying capacity evaluation, overtemperature alerting, and overheating protection. Related Articles | Metrics

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Research on electrical fire comprehensive early warning method based on probability alarm Wang Jingchuan, Li Ming, Wu Jianbin 2025, 44 (10):  1524-1529.  Abstract ( 76 )   As one of the primary types of fires in China, electrical fires have long posed a serious threat to public safety and property. Traditional fixed-threshold alarm systems often suffer from poor adaptability in complex and variable electrical environments, leading to high rates of false alarms and missed detections, thereby limiting their early warning effectiveness. Against this problem, this study proposes a comprehensive early warning method for electrical fires that integrates a probabilistic alarm model. A dual-layer dynamic risk assessment framework is constructed by integrating Bayesian Networks with Long Short-Term Memory (LSTM) neural networks. This framework enables joint modeling and temporal analysis of key risk features such as line overheating, luminous connection, fault arc, etc. A set of early warning indicators is established along with corresponding data acquisition and processing strategies. On this basis, a comprehensive early warning platform is developed, incorporating data analysis, risk assessment, and warning notifications. Preliminary tests on small-sample datasets demonstrate the method’s ability to effectively distinguish between normal and fault conditions, showing high accuracy and promising applicability. This research offers a new pathway for developing intelligent electrical fire monitoring and early warning systems. Related Articles | Metrics

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Glowing contact fault detection technology based on multi-feature fusion neural network Yang Pengtao, Lyu Liang, Zhu Kai, Ji Shengchang, Xu Yang 2025, 44 (10):  1530-1539.  Abstract ( 23 )   Glowing contact faults in electrical circuits caused by poor connections are highly prone to triggering electrical fires, but the locations of glowing contact faults are often unknown. To solve the detection trouble, this paper builds a glowing contact experimental platform, focusing the detection on the loop current of the experimental circuit, and extracts its time-domain, frequency-domain, and time-frequency domain features. To address the problems of small sample size and data imbalance in actual scenarios, a Wasserstein Gradient Penalty Generative Adversarial Network is established for data augmentation. Finally, a one-dimensional convolutional neural network is built to identify new samples obtained in the laboratory. Experimental results show: glowing contact faults and normal loop currents can be distinguished in the characteristic frequency band of 5~15 kHz. The built glowing contact fault identification model achieved a training accuracy of 99.93%, successfully realizing fault identification for 15 sets of loop states obtained from the laboratory. Related Articles | Metrics

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Digital twin electrical fire intelligent early-warning monitoring system design and application Pi Fangsi, Wu Jianbin, Tian Ze 2025, 44 (10):  1540-1546.  Abstract ( 33 )   To address the issues of strong concealment and lack of timely warning for electrical fires, an intelligent early monitoring system for electrical fires integrating digital twin technology has been designed. The system is built upon a "cloud-edge-end" integrated architecture, and deeply incorporates the five-dimensional digital twin model theory. It integrates key technologies such as multi-dimensional sensing, artificial intelligence, and big data analytics to achieve full-process intelligence from data acquisition and edge analysis to cloud fusion. Front-end devices collect multi-dimensional operational data from the electrical system. The edge computing module enables real-time processing and early warning responses. The cloud platform integrates the digital model of the power distribution system, twin data, an electrical insulation aging prediction model, and a risk assessment model, comprehensively displaying the operational status and potential risks of the electrical system. Fire risk distribution is intuitively presented through a "unified risk map", achieving precise characterization of the digital twin model for a three-level power distribution system. This approach enhances proactive perception and intelligent prevention and control capabilities for electrical safety, providing comprehensive safety assurance for electrical systems. Related Articles | Metrics

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Diagnostic method for electrical circuit glowing contact based on EWT-WOA-ELM Lyu Liang, Yang Pengtao, Zhu Kai, Xu Yang, Ji Shengchang 2025, 44 (10):  1547-1559.  Abstract ( 16 )   Poor contact is a common cause of fire in low-voltage lines. When the poor contact reaches a certain high temperature, it will lead to glowing contact fault of electrical lines, which has great potential fire hazards. In order to diagnose the glowing contact fault of electrical circuit, this paper proposes a time-frequency domain feature extraction method based on empirical wavelet transform (EWT), and uses the whale optimization algorithm (WOA) to obtain the optimal input weights and hidden thresholds of extreme learning machine (ELM) based on the fusion feature set, and proposes a neural network model based on EWT-WOA-ELM. The results show that the optimal number of neurons in the hidden layer of the model is 18. The cross validation average accuracy and average cross entropy loss of this model are 96% and 0.623 9, respectively, achieving fault diagnosis for normal state, early and late stages of glowing contact under different operating conditions. Different laboratory data were used to validate this model, and it was found that the model's recognition state was consistent with the actual state. Related Articles | Metrics

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Positioning method of localized overheating defects in cables based on time-domain reflection method Zheng Jiankang, Chu Ziping, Zhang Hui, Qi Junkai, Sun Hailin 2025, 44 (10):  1560-1565.  Abstract ( 15 )   To investigate early warning methods for fires caused by power cable overheating, an experimental platform based on the time-domain reflectometry (TDR) method was established for locating localized overheating defects in cables. Both offline and online localization experiments were conducted, with the localization performance of the TDR method evaluated using localization error metrics. Results indicate that offline localization achieved an error rate not exceeding 1.86%, demonstrating excellent localization effectiveness. To enable online localization, a high-pass filter was configured between the cable and the TDR to suppress power-frequency interference and ensure high-frequency pulse transmission. This filter was designed as a 5th-order Butterworth high-pass filter with a cutoff frequency of 221.1 Hz and 60.21 dB attenuation at 50 Hz. Simulation and experimental verification confirmed it met design specifications. Online localization experiments revealed that the test signal injection efficiency remained high, with a measured positioning error of 7.8%. These research findings hold significant importance for preventing sudden large-scale power outages, effectively enhancing firefighting efficiency, and reducing the probability of cable duct fires. Related Articles | Metrics

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Using capacitor current isolation method to prevent forest fires caused by single-phase grounding in distribution networks Liu Jian, Zhang Xiaoqing, Chang Xiaoqiang, Zhang Zhihua, Yang Guo 2025, 44 (10):  1566-1572.  Abstract ( 17 )   To prevent bush fires caused by single-phase grounding faults in distribution networks crossing high fire-risk forest areas, the ignition conditions for forest fires caused by single-phase grounding is described. The relationship between zero-sequence voltage and system capacitive current during single-phase grounding is analyzed. An approach to prevent forest fires caused by single-phase grounding in distribution networks for isolated neutral systems, arc suppression coil grounding systems as well as small resistance grounding systems is proposed, which involves using an isolation transformer to isolate the capacitive current of the distribution feeder segment crossing fire-risk areas from the system's capacitive current, and configuring an automated intelligent switch downstream of the isolation transformer. This reduces the capacitive current in the feeder section crossing fire-risk areas, thereby enhancing the ability of single-phase grounding detection to withstand high transition resistance and preventing bush fires caused by single-phase grounding faults. Technical issues such as differentiated configuration strategies for isolation transformers and intelligent switches, relay protection coordination, and circuit broken down handling are discussed. Experiment results of full scale test and typical case demonstration show its feasibility. Related Articles | Metrics

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Study on the effectiveness of compressed air foam extinguishing transformer fire in confined space Wang Yani, Wang Liyong, Ye Kuan, Zhao Jinlong 2025, 44 (10):  1573-1578.  Abstract ( 19 )   To investigate the effectiveness of compressed air foam system (CAFS) in suppressing and extinguishing transformer fires in underground confined spaces, this paper conducted full-scale extinguishment tests at 110 kV for various transformer fire scenarios. It analyzed the variation patterns of parameters such as foam concentrate mass, drainage time, extinguishment process, and characteristic temperatures in different regions of the confined space. The cold spray results indicated that the sprayed foam could rapidly cover the protected area, with the transformer top region experiencing the highest foam coverage, reaching a maximum of 50 kg/（m²·min）. This was primarily attributed to the fact that 3/4 of the nozzles in the CAFS spray pipe were directed towards the top of the transformer. The 25% drainage time of the foam was 220 s. The extinguishment test results demonstrated that CAFS could extinguish transformer fires in different scenarios within confined spaces, with the most unfavorable fire scenario being extinguished in 14 s. CAFS exhibited significant cooling effects on the foam-covered areas but less effective cooling in areas where the foam concentrate could not directly act. It is recommended to adopt additional measures to assist in temperature reduction in practical applications. Related Articles | Metrics

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Research on performance evaluation technology of arc fault detection devices under residential electrical characteristic loads Chen Bin, Ma Nan, Ma Junming, Chen Qinpei4 2025, 44 (10):  1579-1584.  Abstract ( 21 )   Electrical fires caused by arc faults are a frequent occurrence. This paper presents a comparative analysis of detection algorithms of Arc Fault Detection Devices (AFDDs) available on the market. The typical household electrical characteristic loads are selected, and an evaluation system for AFDD performance is established. Three key performance indicators—coefficient of variation of breaking time, breaking time speed, and the number of false trippings—are introduced and quantified. The entropy method is applied for weight allocation to develop a performance-based quantitative assessment method. The evaluation is validated with AFDD based on Fourier transform detection method, wavelet transform detection method and artificial neural network detection algorithm. The testing and analysis are conducted in accordance with the national standard GB/T 31143-2014 as well as the performance quantification evaluation method proposed in this paper. The verification results have identified AFDDs that fail under specific residential characteristic loads, demonstrating that the performance quantification evaluation system proposed in this paper can effectively measure the performance of AFDDs under typical residential electrical characteristic loads, offering valuable insights for real-world electricity usage scenarios in households. Related Articles | Metrics