最新刊期
卷 61 ， 期 4 ， 2025
- 摘要：For achieving rapid post-seismic state assessment of electrical equipment and ensuring effective emergency decision-making and post-disaster recovery of power systems, a kind of machine learning-based assessment method is proposed in this paper. The ±800 kV dry-type smoothing reactor is taken as the research object, and Abaqus finite element model is set up for seismic response analysis so to determine its weak seismic points. A large number of seismic waves are input into the finite element model to obtain the machine learning data set required for setting up the assessment model. The redundant features are removed by using correlation analysis and its assessment performance is compared by selecting different machine learning algorithms. The shapley additive explanations (SHAP) is used to explain the assessment model so to avoid the black-box characteristics of machine learning model. The results show that the weak seismic point of the smoothing reactor is in the stress response at the root of the supporting insulator. The assessment model based on the XGBoost algorithm possesses the optimal performance. The SHAP method can effectively reveal the influence of seismic parameters on the post-seismic state at both global and local levels. The assessment model setting up based on the machine learning algorithm can quickly and accurately assess post-seismic state of the equipment and provide technical support for the establishment of intelligent disaster prevention systems of either substation or converter station.关键词：±800 kV dry-type smoothing reactor;post-seismic assessment;machine learning;SHAP method94|30|0更新时间：2025-05-25
- 摘要：The seismic response analysis efficiency of seismic correlation section of electrical equipment of substation is low due to nonlinear structure of flexible structure of substation. In order to improve the correlation analysis efficiency of electrical equipment of substation, a Kriging model for predicting the mean value and variance of seismic response of seismic correlation section based on the numerical analysis model of electrical equipment seismic correlation section is set up. On this basis, the normality test of the seismic response results of the seismic correlation section is performed, the selection method of Kriging correlation function based on semi-variance analysis is proposed, and the statistical value prediction of the seismic response of the seismic correlation section of electrical equipment with different vertical span ratio of flexible wires is developed. The study results show that using Gaussian model as the correlation function of Kriging model can better predict the seismic response of the correlated section, and Kriging model can better predict the seismic response of the flexible wire-electrical equipment seismic correlation section with strong nonlinearity, which can greatly improve the seismic response analysis efficiency of electrical circuit of substation and reduce the analysis cost.关键词：electrical equipment;seismic correlation section;Kriging model;correlation function;seismic response statistics44|16|0更新时间：2025-05-25
- 摘要：For enhancing both accuracy and real-time capability of damage identification for UHV converter station equipment in seismic period, in this paper a damage identification method of equipment based on long short-term memory (LSTM) networks combined with wavelet scattering feature extraction is proposed. The real data containing different damage conditions is formed by simulating the acceleration response of the converter station equipment in the seismic period through finite element simulation. The wavelet scattering technology is used was to extract features from the acceleration signals so to effectively reduce noise and preserve damage-related features. These extracted features are then input into the LSTM model for damage identification. The results show that the LSTM network based on the wavelet scattering features significantly improves both speed and accuracy of damage identification compared to that directly using raw acceleration data, and the final identification accuracy of the model is up to 95%. This method improves effectively both accuracy and efficiency of seismic damage identification of converter station equipment, provides reliable technical support for health monitoring and post-disaster assessment of such power infrastructure as converter station and has broad engineering application potential.关键词：UHV converter station equipment;seismic damage identification;LSTM network;wavelet scattering;deep learning36|22|0更新时间：2025-05-25
- 摘要：The valve-side bushing of converter transformer is a key component in electrical equipment and its safe operation is crucial for the reliability of power system. For exploring the impact of seismic action on the temperature field of the valve side bushing of converter transformer, a detailed finite element simulation model for the ±800 kV converter transformer and bushing system is set up in this paper to develop seismic response analysis of valve side bushing of converter transformer, study the residual deformation and residual stress of lamella contact finger electrical connection structure of the valve side bushing after the seismic, calculate the contact resistance based based on the contact resistance calculation formula of electrical connection structure and analyze temperature variation of the valve side bushing after seismic. The result shows that under the seismic action the contact finger is deformed, the contact stress is decreased and contact resistance is increased. Since the ring-shaped structure of the lamella contact finger results in inconsistency of degrees of deformation of contact finger at different positions, causing distribution difference of the resistance at reach area of the contact finger. The current is concentrated in the area with low resistance, leading to a redistribution of the electrical connection structure and resulting in both overall and partial temperature increases and posing a danger to the thermal stability and power transmission efficiency of the system. The study result reveals the impact of seismic action on the temperature field of the valve-side bushing of converter transformer and provides theoretical basis and technical support for improving seismic design and operation as well as maintenance of converter station.关键词：valve-side bushing;seismic action;residual deformation;temperature field simulation35|16|0更新时间：2025-05-25
- 摘要：The seismic performance of the main equipment of UHV (ultra-high voltage) converter station in seismic-prone area is related to safety and stability of the transmission system under long-term operation. In this paper, the seismic performance of the main equipment of a specific UHV converter station is systematically classified, the assessment method for the seismic performance of the main equipment under the operating condition is proposed. The operation and maintenance strategy of typical ±800 kV UHV DC (direct current) wall bushing equipment is studied and the seismic performance assessment method of the main equipment of the UHV converter station under the operating condition is assessed. The results show that the main equipment of the converter station can adopt differentiated seismic performance assessment strategies according to different categories, and the main equipment with damping measures needs subjecting to mechanical performance tests so to ensure the safety of its structure. The seismic performance assessment method of main equipment of the converter station under operating condition includes finite element analysis, on-site test, structure test, and comprehensive comparison and analysis. The operation and maintenance strategy can adopt the routine and professional operation and maintenance strategy. The method based on on-line monitoring is helpful in better assessing the overall operation condition of the converter station.关键词：UHV converter station;electrical equipment;seismic performance;assessment method;on-site test30|17|0更新时间：2025-05-25
- 摘要：As the core part of flexible converter valves, the converter valve assembly is expensive in construction and its seismic performance is directly related to the seismic safety of the complete converter valve system. In this paper, the method of seismic simulation shaking table test is used to study the seismic performance of certain type of real converter valve assembly. First, a finite element model of the valve assembly is set up to reasonably arrange the measurement points, the dynamic characteristics and weak seismic chain of the valve assembly is preliminarily defined through numerical simulation so to provide the base for the measurement point arrangement of the shaking table. Then, the white noise excitation is input through the seismic simulation platform to measure the frequency and damping ratio dynamic characteristic parameters of the valve assembly. After that, the strain and acceleration response of the valve assembly is measured by inputting 5 sinusoidal beat and artificial seismic wave along such three directions as lateral, longitudinal, and vertical directions to measure the strain and acceleration response of the valve assembly. Finally, it can be judged in accordance with the test result of the shaking table and the function test result of the equipment after test that this type of valve assembly of can meet the seismic requirement of the seismic area with seismic intensity at 9 degree. The method studied in this paper has important reference for the check of similar seismic performance of similar equipment.关键词：ultra high voltage transmission project;valve assembly;seismic performance;seismic simulation shaking table test;numerical simulation method26|18|0更新时间：2025-05-25
- 摘要：The vulnerability of the mechanical clamped type bushing for 500 kV transformer is high under seismic action and the leakage of insulating oil of bushing is likely to occur. For studying the seismic performance of the mechanical clamped type bushing flange, a certain type of 500 kV mechanical clamped type bushings joint is adopted in this paper to perform quasi-static lateral push tests under three different loading conditions. The damage phenomena and mechanisms of the mechanical clamped type flange joint and the porcelain bushings under seismic action are studied. Through the decomposition of the top displacement and the derivation of the bending stiffness formula, the stiffness variation of the mechanical clamped type flange joint under seismic action is analyzed. The results show that the reciprocating vibration of the mechanical clamped type bushing under seismic action will cause the extrusion de-formation and displacement of the sealing ring at the root of the porcelain bushing and the damage phenomena of ceramic fracture. The tensile stress at the weak part of the hitch lug is relatively large, which is consistent with the damage phenomenon in the seismic damage. Based on the quasi-static lateral push test data and theoretical analysis, the bending stiffness empirical coefficient in the bending stiffness calculation formula of the mechanical clamped type flange joint of the 500 kV transformer is corrected.关键词：transformer bushing;mechanical clamped type flange;quasi-static test;damage phenomenon;stiffness analysis24|18|0更新时间：2025-05-25
- 摘要：The electrical equipment in substation may be severely damaged in the seismic condition. Most of previous studies have focused on the seismic performance of single devices or single-span coupled systems, but in practice, multiple devices coupled through flexible wires will affect the seismic response of other equipment. Therefore, a kind of numerical solution based on motion equation is proposed for the seismic response of multi-span flexible wire-single device coupling system. For the accuracy of the method, a corresponding finite element model of the five-span coupling system containing six different electrical equipment is constructed, and the seismic response analysis results of both are compared. Then, the effects of equipment frequency and the vertical span ratio of the flexible wire on the seismic response of the coupling system are studied. The analysis shows that the numerical method is in highly agreement with the calculation result of the finite element model, and the absolute values of the maximum relative errors of peak acceleration and relative displacement are 9.85% and 10.64%, respectively, and the wire tension and seismic response of equipment as well as the frequency ratio of adjacent equipment are positively correlated. This method has practical significance for improving the seismic design and configuration of electrical equipment at substation.关键词：electrical equipment;seismic response;multi-span coupled system;flexible wire;numerical simulation;finite element model;equipment frequency;vertical span ratio23|16|0更新时间：2025-05-25
- 摘要：In recent years, composite pillar insulation equipment has been used gradually in ultra high-voltage (UHV) substations. However, its elastic modulus is smaller than that of ceramic equipment, which makes the rigidity of equipment more low and system more flexible. For studying the seismic performance of its coupling system and the influence on such factors as seismic intensity, the structural dynamic response analysis theory is introduced firstly in this paper. Then, the Abaqus software is used to set up a ±800 kV composite double-pillar insulator equipment system with a tubular-bus coupling, one end of the system is fixed and the other end is sliding. After that, the modal vibration shapes of the system in different directions are analyzed and compared, the dynamic response analysis is per-formed based on the established simulation model and the influence of seismic intensity, spectrum and multi-dimensional seismic coupling on the seismic response of the coupling system is considered respectively. The results show that the first three in-plane frequencies of the coupling system are higher than the corresponding out-of-plane frequencies. When the seismic amplitude is in the range of 0.4g, the root of the insulator strains, the top acceleration and displacement response of the insulator are approximately linearly related to the seismic amplitude. The tubular busbar coupling effect, either for the fixed connection or for sliding connection, can maintain its reduction effect on the top displacement and can reduce the bottom stress level. Under multi-dimensional seismic input, the acceleration in the original direction increases with the increase of the seismic dimension. The displacement response of the coupling composite pillar insulator is large under seismic at 0.4g, and the ratio of displacement to the height of insulator height is up to 1/31, but the root strain level is low and is still at the linear elastic stage.关键词：seismic response;tubular busbar;coupling effect;UHV equipment;composite insulator;seismic coupling23|23|0更新时间：2025-05-25
- 摘要：The impact of seismic action on ultra-high voltage (UHV) converter station equipment is significant. The coupling effect of equipment can greatly change their seismic response characteristics due to the connection between equipment via through busbar and other parts. The typical AC filter circuit in a UHV converter station is taken as an example, a refined finite element model is set up to perform the modal analysis for the dynamic characteristics of the coupled circuit and seismic time-history analysis. The coupling response characteristics of equipment and busbar under different seismic excitation are explored. The study shows that, compared to the individual equipment, the equipment in the coupled circuit exhibits different dynamic behaviors, and the coupling effect has significant influence on the displacement and stress responses of the equipment. The displacement and stress response of some such key components as capacitors and circuit breakers is bigger. Based on the analysis result, a specific seismic design recommen-dations are proposed in this paper so to mitigate the adverse influence of coupling effect and enhance the seismic performance and safety of equipment of converter station.关键词：converter station;AC filter circuit;coupling responses;numerical simulation;seismic responses analysis21|17|0更新时间：2025-05-25
- 摘要：The DC filed, as the core assembly of the converter station system, is usually composed of multiple pillar equipment and wire connection to form a coupled loop which, due to its highly flexible characteristic, is likely to generate damage under the seismic action. This paper aims to analyze the seismic vulnerability and seismic failure risk of the coupled loop of the pillar equipment in the DC field. The 500 kV coupled loop in the DC field is taken as the object, a refined finite element model is set up, followed by an assessment of its seismic performance. The vulnerable curves of the loop equipment are fitted by using the incremental dynamic analysis in conjunction with the nonlinear least squares method. A seismic hazard analysis method based on Monte Carlo sampling is proposed, and the seismic failure risks of key equipment and the overall loop are compared and analyzed. The results show that the root stress response of the support insulators PI1-2, PI1-10 and the current transformer CT is relatively high, making them the critical weak equipment in the coupled loop loop. Under the seismic intensity at 0.4g, the failure probability of the loop has already exceeded 50%, and the seismic failure risk of the overall loop is higher than that of individual equipment in the loop. The longer the service time is, the larger the risk difference of the seismic failure is. The corresponding conclusion can provide a theoretical foundation for seismic analysis and the development of measures to enhance the seismic resilience of the loop.关键词：pillar equipment;coupled loop;seismic failure risk;seismic fragility curves;Monte Carlo18|18|0更新时间：2025-05-25
- 摘要：In recent years, the strong seismic has caused serious threat to the normal operation of power system. Therefore, it is particularly essential to perform seismic analysis and assessment of key structures of the power system. In this paper, the seismic performance assessment of a transmission tower and the associated tower-line coupling system in a 220 kV high-voltage transmission line is performed. Firstly, The finite element model of the tower structure and tower-line coupling system is set up by using Abaqus software to analyze its dynamic performance, stress of the tower leg members, node displacement, and acceleration response. The influence of the conductor coupling on the dynamic of the transmission tower is obtained through comparing the dynamic performance and response peak of a single tower and tower-line system. The result shows that the fundamental frequency of the transmission tower in the coupled system is about 6%~9% lower than that of the single tower model and the structural fundamental frequency is reduced due to the existence of the conductor and ground wire. Due to the effect of the conductor and ground wire, the linear relationship between the peak seismic response of the tower and the peak motion acceleration becomes into a nonlinear relationship. Under the low intensity, the seismic response of the transmission tower in the tower-line coupled system is higher than that of the single tower model and, with the increase of intensity, the seismic response of the tower in the coupled system, compared to the single tower model, tends to gradually decrease. Both the node displacement peak and node absolute acceleration peak of the transmission tower in the tower-line coupled system are lower than those of the single tower model. In the vertical line direction, the nonlinear vibration damping effect of the conductor and ground wire is significantly stronger than its mass amplification effect.关键词：transmission tower;seismic response;coupling system;conductor wire;non-linear vibration17|16|0更新时间：2025-05-25
- 摘要：The seismic disaster survey shows that substation has higher vulnerability under the strong seismic action, which significantly affects post-seismic disaster recovery and rescue efforts. In this paper, a 220 kV substation is taken as a case study to perform the sampling simulation of the system disaster, and the mixed integer linear programming (MILP) is used to generate optimal repair decision sequence. In this study, the MILP decision result is used to train an artificial neural network (ANN) model. The repair strategy based on the model is proposed and is suit-able for scenarios which is lack of high performance calculation condition. Then, the repair priorities for various components of substation after the seismic is analyzed, which can achieve the repair strategy in case of unknown fault position after the disaster. Finally, the seismic resilience retrofitting of substation is performed by using three distinct retrofitting strategies. The result shows that compared to MILP strategy, the ANN-based repair strategy can significantly reduce computational costs while maintaining the efficiency of repair decisions. In addition, The optimal retrofit-ting strategy with different budget is given. The effectiveness of the repair strategies and retrofitting strategies proposed in this paper are verified by those results.关键词：substation systems;seismic resilience;system recovery;resilience enhancement18|17|0更新时间：2025-05-25
- 摘要：With the widespread application of gas-insulated transmission lines (GIL) in ultra-high voltage converter substation, the impact of seismic on its structural safety has been concerned. In this paper, the response characteristics of GIL under seismic action is analyzed on the basis of a refined finite element model, and specific performance enhancement methods for the seismic weak points are proposed. The study shows that the primary weak points of GIL are located at vertical bends, with such two failure modes as damage of enclosure strength and of internal pull-out of internal conductor joint. Additionally, the dynamic amplification effect of the supports is significant, the acceleration amplification factors generally exceed 2.0, however, the dynamic amplification effect of the supports is not the sole factor determining the seismic performance of the GIL. By increasing the fundamental frequency of the supports and fixing the connections between the supports and the enclosure, the peak of the relative displacement of the internal conductor and the peak stress of the enclosure can be reduced effectively, thereby significantly improving the overall seismic performance. The reinforcement measures can reduce the seismic vulnerability of the GIL by more than 50% when the peak ground acceleration (PGA) exceeds 0.4g. This study in this paper provides theoretical support and practical guidance for improving the seismic performance of GIL.关键词：gas-insulated transmission lines (GIL);seismic performance;finite element analysis;support reinforcement;seismic vulnerability24|18|0更新时间：2025-05-25
- 摘要：The seismic disaster surveys show that the seismic vulnerability of mechanical clamped type bushing in 500 kV transformer is high. For improving its seismic performance, a seismic reinforcement method for the 500 kV mechanical clamped type bushing is proposed in this paper. The mechanical clamped type bushings without reinforcement and with different reinforcement methods are tested and studied under repeated loading. The damage forms and the result in improving the seismic performance are compared under various reinforcement methods. The results show that under strong seismic action, the constraints of the spring clamps on the porcelain bushing are insufficient, leading to oil leakage in the absence of reinforcement. Injection of epoxy resin into the flange cavity can effectively improve the seismic performance of the clamped type bushing. After the reinforcement, the integrity of the flange joint of the clamped type bushing is improved significantly, with coordinated deformation between components. The seismic reinforcement method of the mechanical clamped type bushing proposed in this paper can effectively enhance its seismic performance.关键词：mechanical clamped type bushing;flange joint;oil leakage failure;seismic reinforcement;pseudo-static test;reinforcement effectiveness22|17|0更新时间：2025-05-25
- 摘要：The high seismic zone and strong sandstorm environment in Xinjiang region has significant influence on the seismic and wind-proof performance of ±800 kV DC limit RI capacitor bank. In this paper, the±800 kV DC limit RI capacitor bank at a certain UHV DC converter station in Xinjiang is taken as the study object and the finite element analysis is performed by using the general finite element software Midas Gen. Firstly, the material and section are defined, and the Midas Gen model of the±800 kV DC limit RI capacitor bank is set up. Then, the boundary conditions and load cases are applied to obtain the modal, vibration mode, stress and displacement of the capacitor tower by simulation and analysis. The results show that the ±800 kV DC limit RI capacitor bank meets the seismic requirements of 8 degrees (0.2g). In view of the influence of the strong sandstorm environment on the displacement vibration of the capacitor tower in Xinjiang region, a windproof reinforcement measure which can effectively reduce the displacement of the capacitor tower is proposed. The simulation results of Midas Gen show that the windproof reinforcement measure has a significant effect on reducing the displacement of the capacitor tower, providing a theoretical basis for the design and improvement of the±800 kV DC limit RI capacitor bank under the high seismic zone and strong sandstorm environment conditions in Xinjiang region, and ensuring the safe and reliable operation of UHV engineering equipment.关键词：Midas Gen;capacitor tower;seismic resistance;wind load;displacement;finite element model25|16|0更新时间：2025-05-25
- 摘要：Converter transformer is the core equipment in converter station and its valve-side bushing, which extends horizontally and obliquely from the oil tank, is significantly affected by vertical seismic action. For enhancing the seismic performance of the converter transformer, a three-dimensional seismic isolation system, consisting of a sliding friction pendulum horizontal isolation system, a spring-viscous damper vertical isolation system and an anti-rocking device, is proposed. This isolation bearing is applied to a ±800 kV converter transformer. The seismic responses of the converter transformer before and after the installation of the seismic isolation system are calculated and analyzed through finite element numerical simulation. The results show that the three-dimensional seismic isolation significantly reduces the acceleration responses of the valve-side bushing at horizontal and vertical directions. Compared to horizontal isolation, the stress isolation efficiency at the root of the valve-side bushing of the three-dimensional isolation system is increased by approximately 12%. The displacement responses of the isolation system are mainly concentrated at the bearings, and the displacement of the upper structure, with the busing in particular, is significantly reduced than before isolation. The three-dimensional seismic isolation effectively enhances the seismic performance of the converter transformer and has excellent applicability in regions with high seismic intensity.关键词：converter transformer and bushing;horizontal seismic isolation;three-dimensional seismic isolation;seismic response;isolation effectiveness21|14|0更新时间：2025-05-25
- 摘要：The ultra-high voltage (UHV) direct current (DC) wall bushing is a horizontally-installed cantilever component for connecting the valve hall and the DC field in UHV converter stations and its seismic performance is essential to the safe operation of the converter station. The dynamic characteristics and seismic response of the structure of the wall bushing before and after seismic under the consideration of the valve hall is studied by setting up the numerical simulation model of the wall bushing-valve hall system and by selecting the friction ring spring dampers (FRSDs) as energy dissipation device. The multiple stripes analysis (MSA) method is adopted to obtain the vulnerability curves based on strength criteria before and after the seismic action. The results show that the axial and horizontal displacements of the wall bushing are mainly affected by the valve hall structure. The seismic response is reduced significantly after adopting FRSDs for seismic reduction. The damage probability of the inner and outer bushing of the wall bushing before and after seismic reduction is reduced significantly. The valve hall mainly affects the horizontal displacement response of the wall bushing under the seismic action and the vulnerability of the structure under the seismic action is higher. The FRSDs scheme effectively reduces the stress and vertical displacement response and significantly improves its seismic vulnerability.关键词：UHVDC;wall bushing-valve hall system;seismic analysis;seismic-reduction technology;seismic vulnerability22|16|0更新时间：2025-05-25
- 摘要：The supported VSC DC converter valve is one of the key equipment of VSC-HVDC transmission technology with high construction cost and important function. It is of great significance to ensure the stable operation of VSC-DC valve in various situations and is necessary to carry out research on its seismic safety. For improving the seismic performance of the supported converter valve, the finite element numerical simulation analysis is adopted in this paper to simulate the seismic response of the valve tower under the condition of applying different pre-stresses to the diagonal insulator, and a new type of vibration damping method-diagonal insulator-ring spring damper is proposed, which is to install ring-spring damper at the end of the original diagonal insulator. The seismic response of the valve tower with different prestressed tilt insulators and the installation of combined damper is compared. The result shows that in case of installation of the combined damper, the top displacement response of the valve tower and the root stress of the equipment are greatly reduced, and the dual control of the root stress and top displacement of the equipment can be achieved, which is of higher value for engineering applications. Considering the engineering reality, re-placing only the outer part of the prestressed diagonal insulators can also achieve better displacement and stress control, reduce the cost while simplifying the construction process of the existing valve tower vibration isolation measures, and has higher engineering application value.关键词：supported VSC-DC converter valve;prestress;ring spring damper;seismic response control23|19|0更新时间：2025-05-25
- 摘要：For studying the vibration characteristics of reactor equipment in attached substations and the propagation of the vibration in the structure as well as controlling the structural comfort issues due to the vibration of reactors, in this paper the vibration characteristics of the reactor are experimentally studied through the method of on-site measurement. A finite element model of the residential building structure of the attached substation is set up and the propagation of the reactor vibration in the structure is analyzed. The structural comfort is evaluated by using the Z vibration level and secondary noise. The vibration isolation effects of different types of vibration isolation bearings added to the reactors are simulated and compared. The results show that secondary noise is the main comfort issue under the vibration of reactors, and the research in the paper can provide a reference for the design of reactor vibration isolation bearings.关键词：attached substation;reactor vibration;on-site measurement;vibration control23|17|0更新时间：2025-05-25
Earthquake Disaster Mitigation and Emergency Responses of Substation System Under Extreme Conditions
- 摘要：In view of the actual needs on the fault detection and foreign object removal of GIS compartment, a kind of detection and maintenance robot of gas-insulated switchgear that combines a flexible arm and a wheeled mobile plat-form is developed. On the basis of this robot, the robot control system with the microprocessor STM32 and the computing module Jetson Xavier NX as the core and fusion of multi-sensor is designed, which realizes the functions of real-time remote video detection and motion control of the robot and, with combination of the foreign object detection and positioning algorithm, realizes a intelligent control scheme of flexible arm. The final test results show that the robot can operate smoothly inside the compartment of GIS, realize fault detection and removal foreign object and possess a good real-time performance.关键词：GIS;flexible arm;wheeled mobile platform;detection and positioning of foreign object33|20|0更新时间：2025-05-25
- 摘要：For exploring the reason of insulation fault of oil-immersed power transformer of wind farms in severe cold regions in winter, the transient operating temperature of the transformer with different load rates under low temperature is calculated by IEEE standard. The simulation model of dynamic migration and diffusion of moisture in oil-paper insulation under dynamic hot spot temperature is set up on the basis of Fick's second law, and the transient distribution characteristics of moisture in insulation board and oil is compared and analyzed. The study shows that in case of temperature rise the moisture migrates from insulation board to oil and vice verse in case of temperature decrease. However, the internal temperature of transformer is generally low due to the cold environment. In case of temperature rise, the moisture migrated out of the insulation board has no time to enter into the insulation board in the temperature reduction stage, leading to gradual increase of moisture concentration in the oil with the time. However, with the sudden decrease of load in the wind farm, the internal operation temperature of the transformer and the moisture dis-solution ability are reduced accordingly. Under the same moisture content, the increase of relative humidity in the oil leads to the the polymerization and even precipitation of water molecules, which seriously endangers the safe and stable operation of oil-immersed transformer.关键词：extreme cold climate;oil paper insulation;hot spot temperature;dynamic distribution of moisture22|19|0更新时间：2025-05-25
- 摘要：The electromagnetic coupling and electrostatic induction action is very strong due to the small spacing, multiple circuits and large voltage level differences of the mixed-voltage and four-circuit transmission lines on the same tower. In order to effectively reduce the level of induced electricity, the phase sequence, layout and type selection of earthing switch of the transmission line shall be reasonably designed. In this paper, a project of a 500 kV/220 kV mixed-voltage and four-circuit power transmission lines on the same tower is taken as the research object, the simulation model based on the ATP-EMTP software is set up, and the influence of the 500 kV double-circuit lines on the induced voltage and induced current of 220 kV double-circuit lines on the same tower under the interactions of such multiple factors as the operation mode, power flow of line, and phase sequence arrangement change is studied. Based on the flexible current sensing technology, the induced current of the 220 kV double-circuit lines is actually measured on site, and the accuracy of the calculation model is further analyzed and verified. The research results show that the magnitude of the power flow of 500 kV double circuit is positively correlated with the electromagnetic induced current of the 220 kV double-circuit lines on the same tower, but the influence on the static inductance level is less. In case of using the arrangement of inverse phase sequence of 500 kV double-circuit of the mixed-voltage and four-circuit on the same tower, the induced current level of the 220 kV double-circuit will be reduced significantly. While, in case of connection of the ground wire in sections, the electromagnetic induction current near the middle of the four-circuits of mixed-voltage is smaller and the junction of the two ends is larger. It has been verified by measurement that the the theoretical calculation value of the induced electricity is slighter larger than the actually measure value and this is related to the selected parameters of the simulation calculation, which reserves sufficient safety mar-gin for the type selection of earthing switch. A technical solution of changing the switching of induction voltage of the open type earthing switch is proposed to solve the problem of insufficient switching induced electricity of the earthing switch of GIS. The research results can provide important basis for the design of the mixed voltage multiple circuit transmission on the same tower, type selection of the grounding wire and the insufficient of switching induced electricity ability of the earthing switch.关键词：four-circuit lines on the same tower;500 kV;induced voltage;induced current;earthing switch27|17|0更新时间：2025-05-25
- 摘要：The complex characteristics of the fault signal in the case of fault of the distribution network bring severe challenges to the study of fault recording of power system. In this paper, the searching step is taken as an adaptive variable, and a kind of fault signal recording method based on the improved adaptive Prony algorithm is proposed. This method takes the mean square relative fitting error as the criterion, and the sub-segment boundary points are searched by the variable step size. At the initial stage of the search, a large step length is used to establish the approximate boundary point, and then the step size is gradually reduced to determine the accurate boundary point of the sub-segment. The simulation results show that the improved adaptive Prony algorithm can significantly improve the computational efficiency while ensuring the correctness and effectiveness of the actual fault signal analysis and processing.关键词：fault recorder;self-adaptation;Prony algorithm;alterable pace23|16|0更新时间：2025-05-25
- 摘要：Such partial discharge detection means as ultra-high frequency and ultraviolet have some problem in defect localization. In this paper, a more effective ultrasonic localization detection means is selected and combined with microphone array technology and beam formation algorithm. Considering the acoustic signal characteristics of partial discharge of power equipment and also based on the characteristics of single-arm and multi-arm spiral array, the array design is optimized to form Archimedes single-arm curve and combine with the matched delay beam forming algorithm so to meet the needs of the present partial discharge localization scene. Further more, the acoustic imaging device is designed on the basis of above technology to display the distribution of sound sources in space in real time in the form of thermal efforts. Through the application in typical power equipment scenes such as transmission lines and substations, the acoustic imaging devices can clearly localize the partial discharge point, and the device, compared to such traditional detection instruments as UV imagers, has relatively higher localization accuracy, can evaluate the type of partial discharge and can provide the test basics for the subsequent equipment in operation and maintenance.关键词：ultrasonic localization;beam forming;microphone array;partial discharge;acoustic imaging device20|17|0更新时间：2025-05-25
Research & Analysis
- 摘要：During the normal operation of the oil-immersed iron core reactor, its vibration is caused by the winding stressing, the magnetostrictive effect of the iron core and the Maxwell force between the iron cores. The axial and radial vibration response distributions of the reactor under three loads are analyzed by constructing a three-dimensional model of the magnetic-solid coupling of the reactor. On this basis, a reactor vibration test platform is set up to obtain the vibration signal of the reactor housing. The vibration signal of the housing is collected by adjusting the axial compression force of the iron core. It is known by extracting the vibration spectrum characteristic under various mechanical states that with the reduction of the axial compression force of the reactor core, the vibration signal spectrum of the housing is changed. Three kinds of Bayesian optimized network classifier models are adopted to identify the mechanical state under different compression forces, and the accuracy rate has reached 94.5%, 94.2% and 95.0% respectively, and the high efficiency of the spectrum feature in combination with the optimization algorithm for the looseness judgement of the reactor core is verified further.关键词：core reactor;magnetic-solid coupling;vibration response;spectral features23|21|0更新时间：2025-05-25
- 摘要：The expansion and butting of 252 kV GIS from different manufacturers has become into a development direction for substation expansion. For ensuring accurate butting of equipment from different manufacturers, the common types and examples of expansion and butting are summarized in this paper. The common encapsulated busbar butting type is taken as the analysis object, the design, verification and check of the expansion interface by way of such methods as design and design of structural dimension and key parameters, electrical performance analysis, mechanical performance analysis, structural inspection in the factory and delivery test are proposed. The the calculation method of interface enclosure and conductor are proposed in this paper on the basis of the dimension and key parameters of previous equipment interface, and the assembly result verification method mainly based on the three-dimensional software simulation, electrical insulation performance analysis method and mechanical performance analysis method mainly based on the software analysis to form a comprehensive expansion interface design and analysis method. It is proved by the dimension inspection in the factory and delivery test result that the applicability of the expansion interface design and analysis method proposed in this paper is stronger, complies with requirement of product design and has stronger engineering reference significance.关键词：GIS;expansion;butting;structural dimension;electrical performance;mechanical performance;delivery test42|25|0更新时间：2025-05-25
Technical Discussion
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