不同铝护套结构对电缆电气特性影响分析

Analysis on Influence of Different Aluminum Sheath Structure on Electrical Characteristics of Cable

国内交联聚乙烯(XLPE)高压电缆一般采用皱纹铝护套结构,然而现有电缆电气特性的参数计算多基于平滑护套结构,未考虑皱纹护套带来的影响。文中从电场分布入手,基于有限元法分析了皱纹护套结构下的电场分布及缓冲层泄漏电流,进而针对护套感应电压、电缆工频电容和电感进行分析,对比平滑护套结构和皱纹护套结构对以上两组电气参数的影响。同时运用公式法对平滑护套电缆进行计算,作为有限元分析结果的对照。结果表明,皱纹结构会造成气隙电场集中,泄漏电流增大,皱纹铝护套结构会降低护套感应电压约10%,增大工频电感约4%,而对工频电容影响仅0.5%。文中的计算结果有助于更加精确的电缆电气建模。

The corrugated aluminum sheath structure for cross-linked polyethylene(XLPE)high-voltage cables is generally adopted in China.However,the parameter calculation of electrical performance of existing cable is mainly based on a smooth sheath structure without considering the influence of the corrugated sheath.In this paper,the electric filed distribution and leakage current of the buffer layer under the corrugated sheath structure is analyzed from the electric field distribution and based on the finite element method,so to analyze the induced voltage of the sheath,power frequency capacitance and inductance of the cable and compare the influence of smooth sheath and the corrugated sheath structure on the above tow sets of electrical parameters.At the same time,the formula method is used for calculation of the cable with the smooth sheath cable and as the the comparison of the finite element analysis result.The result shows that the corrugated sheath structure can cause electric field concentration of sphere gap and increase of leakage current,the corrugated aluminum sheath structure can reduce the sheath induced voltage about10% and increase the inductance about 4%,while its influence on the power frequency capacitance is only 0.5%.The calculation result in this paper helps more accurate electrical modelling for power cable.