一种电力电缆的随机电热退化模型（英文）

In this paper a methodology is proposed to model the stochastic electro-thermal degradation accumulation in cables.The cable life and the reliability are predicted by estimating the accumulated electro-thermal degradation during seasonal load cycles.The degradation is considered,in a novel approach,as stochastic in nature due to variations in the manufacturing process of insulation raw material and in operational and environmental conditions.The methodology is based on estimation of life by using combined electro-thermal life model,simulation of degradation accumulation process under electro-thermal stress in each season of the year based on Miner’s cumulative damage theory and reliability prediction from a probabilistic point of view.A case study is demonstrated on 10 k V XLPE cables which are directly buried in the UK and China.Results show that,the electro-thermal life of the cable is 56 and 69 years in China and the UK,respectively at 50%failure probability,or the life of the cable in the UK would be 13 years longer than in China,when other stresses such as mechanical and environmental are also considered and assumed to be the same.     

操作过电压对电缆绝缘电老化的影响(英文)

Due to the insufficient information regarding the aging phenomenon of cables caused by switching impulses, we aged 15 kV XLPE and EPR cable samples by 10 000 switching impulses in experiments and tested them. Plus in order to compare the aging phenome- non under multi-stress conditions, additional EPR cable samples were aged by rated AC voltage and current with switching impulses superimposed. We used measurements of partial discharge parameters to monitor the cables’ conditions during their aging process, and the AC breakdown voltages measurement to evaluate the cables after aging. Moreover, the Fourier transform infrared (FTIR) spectroscopy measurements revealed the changes of insulation materials after aging. The measurement results confirm that the accelerated aging of cable samples had taken place. The impacts of each individual aging factor are shown through the selected measurements and comparison. The study also helps to assess the reliability of the XLPE and EPR cables under similar condition while serving in power systems.     

用于现场老化交联聚乙烯电力电缆的降解评估参数

The cables are more likely to deteriorate after several years of service in Shanghai,a city with a humid climate and abundant rainfall.Before assessing the aging status of those cables,it is critical to present effective test parameters which are sensitive to the aging process under special field conditions.Therefore,we have performed water tree investigation,tensile test,and differential scanning calorimetry(DSC)test on hundreds of cable samples removed from service.A large number of typical bowtie water trees were found in cable insulation and the water tree content was proposed to characterize the degree of water treeing.Based on Arrhenius Equation and equivalent thermal history parameters estimated from DSC profiles,we also proposed a new parameter ln(t/τθ)to characterize the aging status of cable insulation,Where,t is treated duration andτθis the thermal life under treated temperature.The applicabilities of water tree content,tensile strength,and ln(t/τθ)are tested using the analysis of variance(ANOVA).Then we investigated the relationship between the tensile strength and the water tree content using regression analysis,and analyzed the relationship between ln(t/τθ)and the tensile strength.The results indicated that each of these parameters performs differently with cables which experienced different degrees of age related degradation,and can be used to identify the aging status of field aged cables.The tensile strength can reflect the water treeing condition of field aged cables very well as a commonly used functional parameter.Since ln(t/τθ)is strongly related to the tensile strength,it is an effective parameter to characterize the aging status of field aged cable insulation.Using this newly proposed parameter is more time saving because of the convenience in sampling.     

智能电能表的加速退化试验方案研究

针对加速寿命试验对长寿命产品可靠性评价的不足,采用加速退化试验的方法对智能电能表进行可靠性评价。通过分析影响在运智能电能表可靠性的主要因素,选取了温度、湿度作为加速应力;通过摸底试验和对加速因子的分析,确定了最大加速应力水平及优化后加速应力组合;确定了退化特征量及其失效阈值、样品数量及其分配比例、试验时间及测量次数等试验参数;最后给出了加速退化试验的试验方案。     

一种低压电力线载波通信路由方法

低压电力线载波通信信道常常表现出噪声干扰强、信号衰减大、时变性强,直接影响电力线载波通信的范围,降低电力线载波通信的可靠性.文中通过分析低压电力线网络拓扑结构,提出了一种基于Q学习和改进蚁群系统融合的电力线载波通信路由方法.首先采用Q学习算法对电力线网络进行全局搜索得到各路径上信息素初始值;然后利用蚁群算法正反馈收敛机制以及改进后自适应调整搜索策略得到最优路由.将文中算法与两种蚂蚁系统算法进行仿真对比,结果表明,文中算法能更快地建立起网络中主节点到各从节点的路由,并能根据通信信道的变化动态的维护路由,具有很强的抗毁性和自愈性,提高了低压电力线载波通信的可靠性.     

一种锂离子电池容量退化经验模型

锂离子电池随着时间的推移,其性能逐步下降退化直至寿命终结,往往会导致系统整体功能失效,应用于军事目的将直接导致各种无人作战系统无法完成战略战术预期,失去作战能力。分析了锂离子电池电学特性,给出电池内部阻抗与容量退化的关系,提出一种根据容量退化速率优先确定整数变量的条件三参数容量退化经验模型,并通过不同退化速率的锂离子电池退化实验数据对模型的可性行及实用性加以验证,为基于数据驱动的锂离子电池寿命预测和健康管理提供理论支撑。     

一种改进的并联IGBT模块瞬态电热模型

在大功率系统中,为了扩大电路的功率等级,开关器件往往会并联使用。为了保证绝缘栅双极型晶体管(IGBT)模块工作在安全范围,需要建立并联器件的瞬态电热模型。首先,重点分析了结温变化对损耗产生的影响,通过建立不同开关阶段等效电路分析推导电压、电流变化规律。同时,通过搭建测试电路得出受温度影响的参数与温度之间的定量关系。其次,在考虑并联器件之间的散热路径耦合基础上,提出并分析了一种改进的IGBT并联热阻抗模型。最后,基于损耗模型和热阻抗模型建立IGBT并联电热模型。搭建实验平台比较不同模块安装距离对瞬态结温的影响。与传统模型比较,计算结果与实验测试结果吻合,验证了改进的电热模型的准确性。     

植物绝缘油对绝缘纸热老化速率的影响及其机理(英文)

With the development of new insulation materials,vegetable oil-the best substitute for mineral oil-has gradually been widely used in the liquid insulation of transformers.To investigate the influence of vegetable oil on the thermal aging rate of oil paper,Kraft paper impregnated with mineral oil and vegetable oil have been underwent thermally accelerated aging at three different temperatures.The degree of polymerization(DP) of Kraft paper was measured to indicate the aging degree of insulation paper.The aging rate of Kraft paper in mineral oil and vegetable oil was compared quantitatively,and results showed that vegetable oil retarded paper’s degradation rate and extended its useful lifetime.The reasons contributing to such phenomena were analyzed using X-ray Photoelectron Spectroscopy(XPS) and molecular simulation software.Kraft paper in vegetable oil had larger activation energy.Due to the larger interaction force between water and natural ester molecules,water molecules were easily bonded with natural ester,weakening the hydrolysis process of cellulose.Cellulose was chemically modified by natural ester during the thermal aging process,and the reactive-OH(hydroxyl) groups on the cellulose became esterified with fatty acid esters.Water molecules were firmly bounded to the ester groups on glucose produced by esterification.The long-chain fatty acid esterified to cellulose was parallel with cellulose chains and acted as a "water barrier" to further weaken the hydrolysis process.     

电容器性能可靠性的一种随机过程模型

文章给出了产品的性能可靠性定义 ,然后在分析产品的失效机理的基础上 ,提出用随机过程模型来描述产品的性能参数逼近临界值的过程 ;推导出性能可靠度函数及其参数的估计方法。并以某电容器为例 ,说明了如何选择合适的拟合曲线以及获得分布参数的估计 ,最终得出电容器电容值的性能可靠度 ,证明了该方法在工程上应用的有效性     

一种基于随机森林的停电敏感模型

为深入全面地对不同用电群体用户进行分析,实现停电敏感用户的精准识别,制定针对性的风险防控策略,有效减少客户来电风险,本文提出一种基于随机森林的停电敏感模型,对客户停电的敏感程度进行划分,进而实现差异化地运营管理客户,为营销部、设备部、客服中心等部门提供有效数据支撑,助力电网营销管理。本文将随机森林模型引入停电敏感预测中,并将预测结果与停电工单结合输出停电敏感高风险、中风险、低风险用户。在此基础上,以浙江湖州市2016年1月1日至2018年12月31日的数据为例进行了实例验证。模型结果显示,随机森林的预测结果准确性为88%,模型覆盖率为76.5%,模型的AUC值为0.77,结果优于逻辑回归和神经网络模型,模型的优良性为电网客户服务风险提供有力的数据参考。     

XLPE电缆绝缘老化测试数据库管理系统

采用现代化的管理方法、手段和工具已成为技术发展和技术管理的重要条件。基于绝缘老化数据图片存储的交联聚乙烯 (XLPE)电缆绝缘老化测试数据库管理系统的开发 ,就是对高压交联聚乙烯电缆绝缘老化测试进行技术管理和分析的一种尝试。本文述评了国外在绝缘老化测试和统计方面已取得的成果 ;详细论述了本数据库管理系统的可行性分析、模块设计和主要功能     

Model Validation for Shipboard Power Cables Using Scattering Parameters

Careful analysis of transients in shipboard power systems is important to achieve long life times of the com ponents in future all-electric ships. In order to accomplish results with high accuracy, it ...     

电力电缆的排管敷设方式

在城市电网建设中,电缆排管敷设方式具有优越性。建立了电缆排管敷设的载流量计算模型,计算得出了不同敷设方式下电缆的载流量;有针对性地就新型电缆保护管材在工程中的应用提出设计思路;对排管电缆工井的数量、长度、布置等要素分析论证,提出了解决工井排水的措施。文章可为电缆排管工程的设计和施工提供参考。     

高压电缆缓冲层的设计与工艺研究

高压与超高压交联电缆金属护套与电缆缆芯之间的缓冲层是电缆的重要组成部分,对电缆的机械、热性能具有重要的影响。为研究缓冲层对电缆性能的影响,分析了不同的阻水带的热阻特性与工艺特点,对国产两种同型号不同厂家的电缆进行了对比温升试验,最后讨论和分析了现在国内外高压交联电缆缓冲层的结构与工艺特点。研究表明,具有不同结构与材料的缓冲层,对电缆本体的热阻有显著影响,也对电缆载流量有着很大的影响。在此基础上,对国产电缆的缓冲层设计与工艺提出了一些建议。     

电力电缆及附件招标技术要求

介绍了在电网改造中对10-110KV电力电缆和110kV电力电缆附件进行招标时的技术要求。     

复合支架在高压电力电缆线路中的应用

近年来杭州地区批量输电线路由架空导线改成了入地电缆,如何选取和应用大量支撑和固定电力电缆的支架成为一个突出的问题。通过传统金属电缆支架和复合材料电缆支架技术、经济参数的对比,充分显示了复合材料制成电缆支架的优越性,着重介绍了螺栓固定式复合电缆支架的安装与使用情况。     

经济、便捷的电力电缆识别方法

电缆识别是电缆检修、施工时通常面临的问题,结合开滦发电厂的实际情况,介绍一种经济、便捷的电缆识别方法,达到快速识别电缆的目的。     

基于三芯电缆自取能技术的热状态评估系统研制

三芯电缆沿线由于缺乏可靠的电源,电缆热状态的监测难以有效开展。提出并研制一种基于三芯电缆自取能技术的热状态评估系统。针对三芯 电缆运行状态下电缆周围空间电磁场分布特征,采用了基于分裂绕组的三芯电缆取能技术,创新性地实现了三芯电缆非侵入式电磁感应取能;围绕三 芯电缆取能线圈的输出特性,设计了低损耗AC-DC变换器,避免了由于开关损耗较大而导致取能失败的问题;建立了有限元模型,分析了电缆内部的温 度分布;开展了实验验证,系统在电缆电流有效值为125 A的情况下可以获取峰值为248.3 mV的感应电压,满足系统正常运转的供电需求,建模评估得 出的电缆温度分布与实测值误差小于2%,证明了该自取能式热状态评估系统的可行性和实用性。