检索结果-南通市图书馆

High Voltage 2024年第1期9卷 81-93页

作者： Jun Xie Zhe Zhou Ziqian Liu Haonan Tian Sigang Zhang Qing Xie hebei provincial key laboratory of power transmission equipment security Defense North China Electric Power UniversityBaodingChina State Grid Gansu Electric power Company LanzhouChina

Fibre-reinforced polymer(FRP)/rigid polyurethane foam(RPUF)interface is susceptible to moisture intrusion in addition to natural ageing during operation.This study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics(MD)simulations.Water absorption,shear strength,and leakage current tests were used to clarify the changes in the interface performance.The degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and micro-characterisation.The results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the interface.In addition,water mainly invades the interface through RPUF.After water penetration,the interfacial bonding strength and insulation performance significantly decreased.Plasticisation and hydrolysis of interfacial materials are the main reasons for decreased interfacial adhesion.Hydrolysis can cause irreversible damage to the interface,increasing interface defects and water absorption.The vicious cycle of material hydrolysis is the ultimate cause of interfacial debonding.The polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

关键词： interface polyurethane interfacial

Study on the dynamic mechanical properties of winding-block axial structure considering short circuit strain rate effect

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2024年第2期9卷 380-390页

作者： Xinyu Wang Ping Wang Jianghai Geng Zikang Zhang Fangcheng Lü Shuguo Gao hebei provincial key laboratory of power transmission equipment security Defense North China Electric Power UniversityBaodingChina State Grid hebei Electric power Research Institute ShijiazhuangChina

Transformers may suffer multiple short-circuit impacts during long-term operation,and axial instability is one of the typical types of serious accidents caused by short-circuit faults.The axial instability form of the winding-block structure is analysed,and the dynamic solution of the winding short-circuit electromagnetic force is obtained by estab-lishing the three-dimensional magnetic-circuit-force multi-physical field coupling simulation model.The influence of strain rate on the cushion block constitutive equation is corrected,and the modified model is verified by short-circuit impact test and quasi-static test.The research results show that for 110 kV 31.5 MVA transformers,the maximum electromagnetic axial resultant force of winding is 363.16 kN,and the ultimate tilt force is 1214.2 kN.The pre-tightening force configuration is accordingly recom-mended to range from 363.16 to 608.28 kN,which is narrowed by 18.49%compared with the static calculation method;Meanwhile,adding a logarithmic strain rate correction term to the classical constitutive equation of the cushion block can achieve a good correction of the stress-strain relationship with the coefficient of determination above 0.99,and the cushion block has a larger elastic modulus under high strain rate load.The research results provide an important theoretical reference for the axial stability structure of transformers.

关键词： axial correction structure

Spatially continuous transformer online temperature monitoring based on distributed optical fibre sensing technology

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2022年第2期7卷 336-345页

作者： Yunpeng Liu Xinye Li Huan Li Junyi Yin Jiaxue Wang Xiaozhou Fan State key laboratory of Alternate Electrical power System with Renewable Energy Sources North China Electric Power UniversityBaodingChina hebei provincial key laboratory of power transmission equipment security defence North China Electric Power UniversityBaodingChina

Transformer internal thermal monitoring exists huge blind areas,and it is difficult for traditional methods to get fully distributed temperature in real time.In this contri-bution,the distributed optical fibre sensor was creatively applied inside an operating 35 kV oil‐immersed transformer which is also qualified for actual power grid oper-ation through the ex‐factory tests.Furthermore,the full‐region temperature along the windings and iron limbs were firstly monitored in a spatiotemporally continuous manner and the hotspots were also closely traced,fluctuating at 90%of the high‐voltage winding height(80%for low‐voltage winding)during the whole process of the heat‐run test.Corresponding Finite Element Method(FEM)for thermo‐fluid field calculation was then utilized for deeper analysis.On the former basis,the actual detected temperature distributions(both spatial and temporal)were compared with the International Electrotechnical Commission traditional model and some modifi-cations were suggested based on the real time measured data.This novel online monitoring application and the detailed internal thermal information may provide a solid reference for the delicate management of power transformers,which also offers a new horizon for the online monitoring in electrical apparatus industry.

关键词： winding fibre Spatial

The influences of silane coupling agents on the heat and moisture resistance of basalt fibre-reinforced composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2023年第1期8卷 38-47页

作者： Yunpeng Liu Mingjia Zhang Hechen Liu Yu Sun Wanxian Wang Jie Liu hebei provincial key laboratory of power transmission equipment security defence North China Electric Power UniversityBaodingChina State key laboratory of Alternate Electrical power System with Renewable Energy Sources North China Electric Power UniversityBaodingChina State Grid hebei Electric power Company Electric power Research Institute ShijiazhuangChina

Basalt fibre composite materials have shown good application prospects in electrical equipment,but their reliability can be affected by damp-heat ageing.In this work,the interface,mechanical,and electrical properties of basalt fibre composites treated with three coupling agents via damp-heat ageing were compared.Molecular simulations were conducted to reveal the damp-heat ageing mechanism of the composites.The results show thatγ-aminopropyl triethoxy silane(KH-550)andγ-glycidoxy propyl trimethoxy silane(KH-560)perform better as coupling agents as they form bonds with the matrix resin,compared withγ-methacryloxy propyl trimethoxy silane(KH-570).After the dampheat ageing treatment,the hydrolysis of the defects of the amino groups in the interface of the KH-550-treated sample can weaken its mechanical properties and insulation properties greatly.The interface layer of the KH-560-treated sample is mostly composed of carbon–oxygen single bonds and methylene groups with its interface structure more stable,which endows the sample with better stability of its mechanical and insulating properties.Therefore,KH-560 is a more suitable coupling agent for processing basalt fibres to be used in electrical equipment.

关键词： composites coupling fibre

The feasibility of continuous basalt fibre-reinforced polymer application to composite cross-arms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2023年第3期8卷 590-598页

作者： Yunpeng Liu Mingjia Zhang Hechen Liu Yunfan Ma Wanxian Wang Xiaohan Dai Jie Liu hebei provincial key laboratory of power transmission equipment security defence North China Electric Power UniversityBaodingChina State key laboratory of Alternate Electrical power System with Renewable Energy Sources North China Electric Power UniversityBaodingChina State Grid hebei Electric power Company Electric power Research Institute ShijiazhuangChina

Composite cross-arms have the advantages of high lightning resistance but impose onerous requirements on mechanical and insulation reliability.Traditional glass fibre composites fail to meet the needs of practical applications.Basalt fibre exhibits better mechanical properties and stability than glass fibre and has potential application value.This study aims to evaluate the feasibility of its application to composite cross-arms.The mechanical,electrical,and physical properties of basalt fibre-reinforced polymer(BFRP)were investigated and compared with glass fibre-reinforced polymer(GFRP).The results indicate that BFRP has better thermal stability and mechanical properties than GFRP.Among them,the temperature at the maximum weight loss rate of BFRP is 14℃ higher than that of GFRP,and the tensile and flexural modulus of BFRP is 43%and 29%higher than those of GFRP.Furthermore,the dielectric losses of BFRP and GFRP at 50 Hz are 2%,and the breakdown field strength is 22 kV/mm,both of which have the same insulation properties.BFRP meets the requirements of composite cross-arm for quality and reliability to ensure the safety and stability of transmission lines.However,the interlaminar shear test and SEM show weak interfacial bonding strength between basalt fibre and resin.Furthermore,micro-computed tomography scanning of BFRP and GFRP and 3D construction of their internal microstructures indicate that the pore defect content of BFRP reaches 0.034%,which far exceeds that of GFRP.These findings show that the wettability and adhesion between basalt fibre and resin must be improved.Developing special sizing agents for basalt fibre is necessary further to improve the mechanical and electrical properties of BFRP.

关键词： fibre basalt composite

Study on operation voltage monitoring and electrothermal coupling simulation of electric multiple unit(EMU)roof arrester

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2022年第2期7卷 357-368页

作者： Qizhe Zhang Shenghui Wang Kaixuan Sun Xinghao Dong Mingliang Liu Fangcheng Lü State key laboratory of Alternate Electrical power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina hebei provincial key laboratory of power transmission equipment security Defense North China Electric Power UniversityBaodingChina

The roof arrester of electric multiple units(EMU)can efficiently limit the overvoltage,and ensure the safe operation of the EMU electrical equipment.In the process of high‐speed operation,the traction power supply system is often affected by overvoltage.In addition,roof arrester explosion accidents occasionally occur.In this paper,the on‐line voltage measurement system of the EMU arrester is developed.By analysing a large number of voltage waveforms,the abnormal voltage is divided into three categories:over‐phase voltage,high harmonic voltage and steep impulse overvoltage.The charac-teristics of abnormal voltage waveforms are then summarised.The electrothermal coupling simulation model of the arrester is developed,and the current response and temperature distribution of the arrester under abnormal voltage are calculated.The impact of the impulse voltage energy on the arrester temperature is studied by applying a triangular wave voltage to the model.Finally,some suggestions are proposed for the operation and maintenance of the roof arrester.

关键词： operation traction coupling

Inverse Proportion Technique Based Scheduling Strategy for Energy Storage System Considering Load Demand Differences

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of power and Energy Systems 2022年第5期8卷 1487-1496页

作者： Hejun Yang Zhenyu Hao Yinghao Ma Dabo Zhang Anhui provincial key laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China State key laboratory of power transmission equipment&System security and New Technology Chongqing UniversityChongqing 400044Chin

The energy storage system(ESS)as a demand-side management(DSM)resource can effectively smooth the load power fluctuation of a power system.However,designing a more reasonable ESS operational strategy will be a prerequisite before incorporating the energy storage device into DSM.As different load levels have different demands for the real-time chargedischarge power of an ESS,this paper proposes a heuristic ESS operation scheduling strategy which can take into account the electrical load demand differences.In this paper,firstly,two demand degree concepts for charging power and discharging power are defined to describe the differentiated ESS demand under the condition of different electrical load levels.Secondly,an inverse proportion technique based ESS scheduling strategy,with the consideration of the load demand difference,is proposed in this paper.Thirdly,some evaluating indices are defined in this paper for describing the influence of the proposed strategy on the smoothing degree of the daily load curve.Finally,several case studies are designed to verify the validity and correctness of the proposed technique,and the results show that the proposed technique can effectively smooth the load curve and improve the ability of peak shaving and valley filling.

关键词： Demand response energy storage system load demand difference operation scheduling strategy peak shaving and valley filling

Anomaly Detection and Pattern Differentiation in Monitoring Data from power Transformers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy Engineering 2022年第5期119卷 1811-1828页

作者： Jun Zhao Shuguo Gao Yunpeng Liu QuanWang Ziqiang Xu Yuan Tian Lu Sun State Grid hebei Electric power Research Institute Shijiazhuang050021China hebei provincial key laboratory of power transmission equipment security Defense North China Electric Power UniversityBaoding071003China State key laboratory of Alternate Electrical power Systemwith Renewable Energy Sources North China Electric Power University Beijing 102206 China

Aiming at the problem of abnormal data generated by a power transformer on-line monitoring system due to the influences of transformer operation state change,external environmental interference,communication interruption,and other factors,a method of anomaly recognition and differentiation for monitoring data was proposed.Firstly,the empirical wavelet transform(EWT)and the autoregressive integrated moving average(ARIMA)model were used for time series modelling of monitoring data to obtain the residual sequence reflecting the anomaly monitoring data value,and then the isolation forest algorithm was used to identify the abnormal information,and the monitoring sequence was segmented according to the recognition results.Secondly,the segmented sequence was symbolised by the improved multi-dimensional SAX vector representation method,and the assessment of the anomaly pattern was made by calculating the similarity score of the adjacent symbol vectors,and the monitoring sequence correlation was further used to verify the assessment.Finally,the case study result shows that the proposed method can reliably recognise abnormal data and accurately distinguish between invalid and valid anomaly patterns.

关键词： Abnormal detection empirical wavelet transform autoregressive integrated moving average isolated forest

Bi-objective Layout Optimization for Multiple Wind Farms Considering Sequential Fluctuation of Wind power Using Uniform Design

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CSEE Journal of power and Energy Systems 2022年第6期8卷 1623-1635页

作者： Yinghao Ma Kaigui Xie Yanan Zhao Hejun Yang Dabo Zhang Anhui Province key laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China State key laboratory of power transmission equipment&System security and New Technology Chongqing UniversityChongqing 400044China School of Computer Science and Technology at University of Science and Technology of China Hefei 230027China

The fluctuation of wind power brings great challenges to the secure,stable,and cost-efficient operation of the power system.Because of the time-correlation of wind speed and the wake effect of wind turbines,the layout of wind farm has a significant impact on the wind power sequential fluctuation.In order to reduce the fluctuation of wind power and improve the operation security with lower operating cost,a bi-objective layout optimization model for multiple wind farms considering the sequential fluctuation of wind power is proposed in this paper.The goal is to determine the optimal installed capacity of wind farms and the location of wind turbines.The proposed model maximizes the energy production and minimizes the fluctuation of wind power simultaneously.To improve the accuracy of wind speed estimation and hence the power calculation,the timeshifting of wind speed between the wind tower and turbines’locations is also considered.A uniform design based two-stage genetic algorithm is developed for the solution of the proposed model.Case studies demonstrate the effectiveness of this proposed model.

关键词： Wind farm layout optimization(WFLO) wind power fluctuation bi-objective optimization uniform design

Dynamic development model for long gap discharge streamer-leader system based on fractal theory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2022年第9期24卷 68-76页

作者：耿江海王权圣刘晓敏王平律方成丁玉剑 hebei provincial key laboratory of power transmission equipment security Defense North China Electric Power UniversityBaoding 071003People’s Republic of China China Electric power Research Institute Beijing 100192People’s Republic of China

Establishing a long air gap discharge model considering the streamer-leader transition and randomness of the discharge path is of great signiflcance to improve the accuracy of discharge characteristic prediction and optimize external insulation design.Based on fractal theory and thermal ionization theory of streamer-leader transition,this work establishes a dynamic development model for the long air gap discharge streamer-leader system,which includes streamer inception,streamer development,leader inception,development of streamer-leader system and flnal jump.The positive discharge process of a 3 m rod plate is simulated to obtain the fractal distribution of the discharge path and the law of leader development for comparison with the discharge test results.The results show that the simulation model is similar to test results in the development characteristics of leader path distribution,each stage time and leader velocity.Finally,a simulation calculation of a 50%breakdown voltage of the rod-plate gap and ball-plate gap is carried out,with results fairly consistent with test data,proving the effectiveness and practicality of the model.

关键词： long air gap fractal theory thermal ionization streamer-leader system simulation model