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High Voltage 2024年第2期9卷 296-308页

作者： Lijun Yang Zhidong Cheng Li Cheng ruijin liao State Key Laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Because DC conductivities of oil-paper materials can be easily affected by electric field and temperature,the electrical properties under electro-thermal coupling of oil-paper materials should be considered when optimising the insulation structure of valve-side winding of the converter *** on the finite element multi-physical field coupling simulation,the multi-objective optimisation of main insulation structure of valve-side winding is carried *** view of the high time consuming of multi-physical field calculation and the actual needs of an insulation structure optimisation,the Kriging method and technique for order preference by similarity to the ideal solution(TOPSIS)method are introduced,and combines them with NSGA-II to obtain a joint algorithm that can be used for the optimisation of insulation structure of the converter *** using the joint algorithm of multi-objective optimisation,the insulation structure configuration scheme of valve-side winding is *** can be seen from the experiment result that,on the one hand,the joint algorithm adopted can obtain the insulation structure configuration scheme that meets the design *** the other hand,when facing the configuration scheme optimisation under multi-field coupling,the computational time required by this method is only 0.15%of that required by original genetic algorithm.

关键词： converter insulation coupling

Effect of the grain boundary character distribution on the sulfur corrosion behaviour and mechanisms of copper windings under different high temperatures

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HIGH VOLTAGE 2024年第3期9卷 566-580页

作者： Dai, Xu Yuan, Yuan Zhou, Jiang Liu, Guoyong Zhu, Tao Xiang, Huiying Yu, Qi Gao, Xue liao, ruijin Chongqing Univ State Key Lab Power Transmiss Equipment & Syst Sec Chongqing Peoples R China Chongqing Univ Coll Mat Sci & Engn Chongqing Peoples R China Dongfang Elect Machinery Co Ltd Deyang Peoples R China

As a typical failure phenomenon in transformers, sulfur corrosion has garnered significant attention in the field of high-voltage engineering. Grain boundary character distribution (GBCD) copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular corrosion. In this study, the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various temperatures were experimentally and theoretically studied. Results show that GBCD can enhance the corrosion resistance of copper in liquid environments. With the increase in temperatures, the insulating properties of oil and papers in traditional copper windings experience notable degradation, while GBCD copper windings show more stable insulating behaviours. In addition, modelling of grain boundary energy indicates that the grain boundary structure of GBCD copper windings has a lower average interface energy of 0.170 eV/angstrom 2. Calculations of reaction thermodynamics show that GBCD copper windings possess a higher failure temperature (135.2 degrees C) and inhibition degree (activation energy) of the sulfur corrosion (32,557.62 J/mol), revealing the stability and enhanced sulfur corrosion resistance at elevated temperatures.

关键词： OIL-PAPER INSULATION DIBENZYL DISULFIDE POWER TRANSFORMERS STAINLESS-STEEL STRENGTH

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变压器绕组热缺陷温度演化规律及其辨识方法

高电压技术 2024年第4期50卷 1548-1559页

作者：张弦亮郝建刘丛王吉祥吴洁廖瑞金输变电装备技术全国重点实验室(重庆大学电气工程学院) 重庆400044

近年来变压器因绕组发生热故障烧毁时有发生,严重威胁电网安全。为保障变压器的安全稳定运行,开展了变压器绕组热缺陷温度演化规律及其辨识方法研究。首先,基于有限元法研究构建变压器绕组电磁-温度-流体多物理场耦合仿真模型,并通过温... 详细信息

近年来变压器因绕组发生热故障烧毁时有发生,严重威胁电网安全。为保障变压器的安全稳定运行,开展了变压器绕组热缺陷温度演化规律及其辨识方法研究。首先,基于有限元法研究构建变压器绕组电磁-温度-流体多物理场耦合仿真模型,并通过温升试验验证仿真模型的有效性;然后,仿真分析绕组不同过热位置、热缺陷严重程度和运行工况对绕组局部区域温度的影响规律;最后,应用绕组轴向油道多点温度突变分析研究提出绕组热缺陷位置和严重程度辨识方法。研究结果表明:基于该文多场耦合仿真模型计算的温度值与温升试验实测值的误差小于6%;绕组不同区域发生热缺陷时,过热区域热量会沿油流导向路径快速传递,绕组油道内多点温升值会随其下方区域过热温度的增大呈现线性规律增长;该文提出的热缺陷辨识方法对热缺陷位置辨识的准确度为100%,对热缺陷温度估计的相对均方根误差为6.1%。采用该研究成果能及早发现变压器运行过程中绕组上的热缺陷,避免由缺陷向更严重的故障发展,保障变压器的安全运行。

关键词：变压器绝缘绕组热缺陷温度分布辨识方法

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面向数字孪生变压器的计算机辅助运维(CAM+)构架与关键技术

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高电压技术 2024年第3期50卷 924-940页

作者：廖瑞金罗豪成立杨丽君赵学童郝建输变电装备技术全国重点实验室(重庆大学电气工程学院) 重庆400044

发展数字孪生变压器对支撑电力装备智能运维具有重要价值。目前变压器已具有计算机辅助设计、工程仿真的一般功能,但面向运行维护的场景、性能数字孪生还处于初级阶段。为此,该文提出了一种将计算机辅助设计、工程仿真、制造进一步拓展... 详细信息

发展数字孪生变压器对支撑电力装备智能运维具有重要价值。目前变压器已具有计算机辅助设计、工程仿真的一般功能,但面向运行维护的场景、性能数字孪生还处于初级阶段。为此,该文提出了一种将计算机辅助设计、工程仿真、制造进一步拓展为电力装备的计算机辅助运维(computer aided maintenance+,CAM+)新模式,包含了场景更新、虚实融合、故障定位、智能运维等功能。该文首先介绍了CAM+的内涵,结合电力装备的数字孪生架构提出了面向数字孪生变压器的CAM+模式的技术架构。然后,综述了3维场景可视化建模、高精度传感、多物理场耦合模型与快速计算、虚实融合的动态推演、多源数据融合、状态智能评估、知识图谱等CAM+模式所涉及的关键技术。最后,分析了CAM+在变压器场景更新、参量孪生和智能运维的应用,并总结了未来CAM+所面临的挑战和发展方向。

关键词： CAM+ 数字孪生变压器虚实融合动态推演智能运维

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基于双向长短期记忆网络含间接健康指标的锂电池SOH估计

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电力系统自动化 2024年第4期48卷 160-168页

作者：方斯顿刘龙真孔赖强牛涛陈冠宏廖瑞金输配电装备及系统安全与新技术国家重点实验室(重庆大学) 重庆市400044

快速准确地对锂离子电池进行全寿命周期的健康状态(SOH)估计有助于提高储能设备的安全可靠性。提出一种基于间接健康指标(IHI)和鲸鱼优化算法(WOA)优化的双向长短期记忆(BiLSTM)网络相结合的锂电池SOH估计模型,该模型考虑了未来状态对当... 详细信息

快速准确地对锂离子电池进行全寿命周期的健康状态(SOH)估计有助于提高储能设备的安全可靠性。提出一种基于间接健康指标(IHI)和鲸鱼优化算法(WOA)优化的双向长短期记忆(BiLSTM)网络相结合的锂电池SOH估计模型,该模型考虑了未来状态对当前SOH的影响。首先,对锂电池恒流恒压(CC-CV)充放电过程进行分析,提取出多个随充放电循环动态变化的电压、电流、温度的时间特征作为IHI,并加入放电负载电压下降时间这一指标;然后,通过相关性分析,从各IHI中筛选出和容量关联度高的IHI作为输入特征;最后,建立基于WOA优化的BiLSTM网络的电池SOH估计模型,并利用美国国家航天航空局锂电池数据集对2个不同工况下的电池SOH进行估计。结果表明,所提方法可有效提高SOH的估计精度。

关键词：健康状态锂离子电池间接健康指标鲸鱼优化算法双向长短期记忆网络

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Microcosmic mechanism and correction of moisture effect on furfural diffusion and equilibrium in oil‐paper insulation

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High Voltage 2023年第4期8卷 772-780页

作者： Dawei Feng Ge Chen Yuandi Lin ruijin liao Dayong Yuan State Key Lab of Reliability and Intelligence of Electrical Equipment School of Electrical EngineeringHebei University of TechnologyTianjinChina The MOE Key Laboratory of Special Machine and High Voltage Apparatus School of Electrical EngineeringShenyang University of TechnologyShenyangChina State Grid Jiangsu Electric Power Company Research Institute NanjingChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology School of Electrical EngineeringChongqing UniversityChongqingChina TBEA Shenyang Transformer Group Co. LtdShenyangChina

Furfural content in oil is considered as an effective parameter to evaluate the ageing state of oil-immersed *** previous thermal ageing experiments at 130℃,we found that moisture increment in oil-paper system makes more furfural distribute in ***,the microcosmic mechanism of moisture effect on furfural diffusion from paper to oil is still unknown,and the furfural equilibrium law at transformers'typical operating temperatures is also unclear,resulting in the unreliability of the existed furfural evaluation *** elucidate the above problems,molecular dynamics simulation and furfural equilibrium experiments at 60℃ were carried out at different moisture *** results show that high moisture content makes part of furfural diffuse from paper to oil *** moisture content increases from 1% to 2%,mass fraction of furfural in oil may increase from 32.98% to 49.83%,leading to furfural content in oil increases from 0.76 mg/L to 1.06 mg/L when the degree of polymerisation of insulation paper is about 524,which increased by 39.5%.The increase in moisture content makes cellulose form hydrogen bonds with H_(2)O preferentially,decreasing the hydrogen bonds interaction between cellulose and ***,partial furfural falls off cellulose and diffuses into oil,leading to an increase in furfural content in *** eliminate the moisture interference,a corrected furfural assessment model based on the moisture equilibrium curve has been constructed,which can accurately evaluate the ageing state of insulation paper regardless of the moisture influence.

关键词： equilibrium insulation diffusion

Research on the feature extraction of DC space charge behavior of oil-paper insulation

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Science China(Technological Sciences) 2011年第5期54卷 1315-1324页

作者： TANG Chao liao ruijin CHEN George YANG LiJun College of Engineering and Technology Southwest University Chongqing 400715 China The State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China School of Electronics and Computer Science University of Southampton Southampton SO17 3B J UK

As the ultra high DC voltage grid comes into an important stage in the ‘Twelfth Five-year Plan’ of China, the requirement on the operation safety of power equipment needs to be improved. Oil-paper insulation plays a significant role as the main insulation material of many key power equipments. The space charge behaviors of oil-paper insulation not only affect the dielectric strength, but also relate to the stability and security of power transmission facilities. Until now, the research on the space charge behaviors of oil-paper insulation remains on the stage of objective description and phenomenon explanation, thus it is very urgent to make some feature extractions on the test results in order to further investigate the DC space charge behaviors of oil-paper insulation. In this paper, based on the large numbers of test data in the first stage, data mining and feature extractions were performed on the DC space charge behavior of oil-paper insulation. The variation laws of some key characteristic parameters obtained in different experiment conditions such as the total charge injection amount, apparent charge mobility, and trap energy distribution were analyzed. In addition, the distribution of trapping level inside oil-paper was calculated by using the PEA test results based on the mechanism of the isothermal decay current, which realized the approximate calculation of trap depth by charge decay characteristics. What’s more, the exponential injection and decay equations of DC space charge changing with time were acquired for the first time, and the physical meanings of related parameters were defined. This has laid a foundation for the prediction and simulation of space charge in the oil-paper insulation.

关键词： oil-paper insulation space charge DC feature extraction

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Classification Method for Mechanical Defects in GIS Equipment Based on Mode Function Analysis and Improved Relevance Vector Machines

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 790-801页

作者： Yao Zhong Jian Hao Xupeng Wang ruijin liao Ruilei Gong Yilin Ding State Key Laboratory of Power Transmission Equipment&System Security and New Technology University of ChongqingChongqing 400044China Shandong Taikai High Voltage Swichgear Co.Ltd. Taian 271000China

Mechanical defects,in gas-insulated switchgear(GIS)equipment,have weak response characteristics,leading to significant difficulties in the classification of ***,this paper proposes a novel mechanical defect feature extraction and classification method that combines independent intrinsic mode function(IIMF)analysis and an improved multikernel mapping fast multi-classification relevance vector machine(MKF-mRVM).Enlightened by the differences in the GIS operating vibration mode,the IIMF series were first obtained based on regenerated phase-shifted sinusoid-assisted empirical mode decomposition(RPSEMD)and modal *** singular value decomposition and time-frequency conversions were performed to construct combined feature ***,multikernel mapping and domain sampling were introduced to improve the calculation speed and recognition accuracy of the mRVM,which was more suitable for on-line *** show that the proposed RPSEMD-MKF-mRVM model achieves a faster training speed(14.23 s)and higher accuracy(98.21%)than other algorithms,and it can adapt to variable loads.

关键词： GIS IIMF analysis mechanical defect MKFmRVM RPSEMD

Molecular pyrolysis process and gas production characteristics of 3-element mixed insulation oil under thermal fault

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High Voltage 2022年第6期7卷 1130-1140页

作者： Dawei Feng Ge Chen Xiaoyu Yan Jian Hao ruijin liao State Key Lab of Reliability and Intelligence of Electrical Equipment School of Electrical EngineeringHebei University of TechnologyTianjinChina Hebei International Joint Research Center for Reliability and Intelligence of Modern Electrical Equipment TianjinChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology School of Electrical EngineeringChongqing UniversityChongqingChina

Mixed insulation oil is considered as a desired substitute for traditional mineral oil.A novel 3-element mixed insulation oil has been developed in our previous works,whose parameters satisfy the mineral oil standard(IEC 60296:2012).In the application of transformer oil,dissolved gas analysis is an effective method for insulation fault *** fault is a common and typical fault in transformers;however,the pyrolysis process and gas production characteristics of mixed insulation oil under thermal fault remain *** this study,the pyrolysis process and gas production characteristics of 3-element mixed insulation oil have been studied through simulation and experiments,and mineral oil is equally treated for *** show that the gas production characteristics of mixed oil are closely related to its base oils,and 3-element mixed insulation oil generates more H_(2)and C_(2)H_(6)under thermal fault,in which the percentage of H_(2)in the mixed oil is always three times that in the mineral *** CO_(2)is produced in mixed oil under thermal fault because of ester bonds;C_(2)H_(4)is also a main characteristic gas for mixed insulation oil under thermal fault,and its proportion increases continuously with the increase of *** mineral oil,the weight loss temperature in thermogravimetric(TG)curve corresponds to evaporation rather than *** esters have poor thermal stability according to simulation results,but they possess high flash point and weight loss temperature in the TG curve primarily because of their large average molecular weight.

关键词： insulation fault pyrolysis

Non-destructive testing method of microdebonding defects in composite insulation based on high power ultrasonic

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High Voltage 2019年第3期4卷 167-172页

作者： Hanqing Wang Li Cheng ruijin liao Sida Zhang Lijun Yang State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqing 400030People's Republic of China

It is crucial to ensure the adhesive quality of the interface in composite insulation equipment for power grid *** to viscoelasticity of silicone rubber and roughness of interface,the thickness of the local air layer in the defective interface is<100μ*** kind of defect is called micro-debonding defect in this paper,and it is significantly smaller than the millimetre-scale air gaps which could be defected by the x-ray,THz,and traditional ultrasonic *** remains challenging to detect the micro-debonding in composite insulation by non-destructive testing *** this paper,the acoustic model and bi-linear stiffness model for micro-debonding in different stages are ***,a conjecture is proposed that the bonding property of composite insulation is related to the acoustic impedance of interface and non-linear distortion of its constitutive *** result obtained from numerical simulation with and without defect is compared with the high-power ultrasonic experimental data to validate the correctness of the theoretical *** addition,it can be concluded that the non-linear distortion of high-power ultrasonic wave can be effectively used to diagnose micro-debonding defect at the interface of composite insulation in its early stage(1-20μm).

关键词： composite insulation interface