110 kV XLPE电缆缓冲层放电灼伤问题的理化分析与仿真研究

Physical and Chemical Analysis and Simulation Study on Discharge Burn Defect of Buffer Layer in 110 kV XLPE Cable

对110 kV及以上高压XLPE电缆线路改造时,频繁发现电缆缓冲层存在疑似放电灼伤缺陷,其原因尚无定论。为探究该缺陷是否为放电产生,文中首先对缺陷进行了形貌特征观察和元素成分表征,然后对阻水带电阻率进行测量,最后利用有限元软件对电缆进行三维电场仿真,研究了缓冲层间隙、阻水带电阻率、过电压等因素对缓冲层场强的影响。研究结果表明:缓冲层存在间隙、阻水带电阻率增大、过电压入侵等因素会使缓冲层场强增大,易造成缓冲层放电现象。

In retrofitting high⁃voltage XLPE cable lines of 110 kV and above,suspected discharge burn defects were often found on the buffer layers,and the reason why the defects occured is still inconclusive.In order to explore whether these defects are due to discharge,this study firstly observed the morphology of the defects and analyzed their elemental composition,and then measured the resistivity of water⁃blocking tape.Finally,three⁃dimensional electric field simulation of the XLPE cable was carried out with a finite element software to obtain the effects of buffer layer gap,resistivity of water⁃blocking tape and overvoltage on the electric field strength of buffer layer.The results showed that presence of gap in buffer layer,higher resistivity of water⁃blocking tape,and intrusion of overvoltage all increased the electric field strength on the buffer layer and caused discharge of the buffer layer.