变频供电对电缆绝缘性能影响的研究.pdfVIP

36 李 岚等：变频供电对电缆绝缘性能影响的研究 绝缘材料 2009，42(3) 变频供电对电缆绝缘性能影响的研究 李 岚 ，刘春玉 (1．中国石油大学(华东)石大科技集团，山东 东营 257062；2．荆楚理工学院，湖北 荆门 448000) 摘要：分析了变频长线供电波反射过电压的产生机理、影响因素及对电缆绝缘性能的危害及变频长线供电波 反射过电压高频振荡的产生机理；在理解PWM 脉冲传输机理的基础上，计算研究了变频器输出电压波形的 上升下降时间、供 电电缆的长度、供 电电缆的波阻抗及系统负载匹配关系对过 电压的影响程度；提出了抑制波 反射过电压的措施。现场应用结果表明，达NT较好地消除波反射过电压的目的，保证了供电系统的可靠运行。 关键词：电缆；绝缘；反射过电压 中图分类号：TM206；TM247 文献标志码：A 文章编号：1009—9239(2009)03—0036—05 The Influences of Variable Frequency Supply on Cable Insulation Property LILan，LIU Chun．yu。 (j．StarScience TechnologyGroup。China UniversityofPetroleum fEastChina)， Dongying257062．China 2．JingchuUniversityofTechnology，Jingmen448000，China) Abstract：The generation mechanism ofreflectedwaveover-voltagepoweredby variable frequency long lines，the influencing factors and its harmfuleffecton the cable insulation property were analyzed．By using the electromagnetic transmission line theory and based on the uniform trans- mission line modeland transmission equation， the problem of reflected wave over-voltage along with high-frequency oscillationwereanalyzed．Due to the distributedparametersandhigh d钆／dt． the output voltage waveform is reflected at motor terminals． The reflected waves lead to over-voltage and stresses on winding insulations． The over-voltage is dependent on the PWM rise—time ofswitching devices and the cable length．A shorter rise-time and a longer cable length may causehigher over-voltage．Atlast，themethodsto solve theproblemswere given．Through the field applications， we have better achieved the purpose of eliminating the reflected wave over-voltage，thusensure the reliable operation ofthe powersupply system ． Keywords：cable；insulation；reflected wave over·voltage 1 前 言 米，甚至是数公里，这就带来了许多期待研究的问