Extensive physical testing has suggested that polymeric material Hifax (Flexible Polypropylene)could be a promising candidate for the next generation of DC insulation. In the work presented in this paper,the DC conduc...Extensive physical testing has suggested that polymeric material Hifax (Flexible Polypropylene)could be a promising candidate for the next generation of DC insulation. In the work presented in this paper,the DC conductivity and AC breakdown of this polymeric insulation material have been measured as a function of temperature. The results show that Hifax cable insulation has a higher AC breakdown strength than EPR and XLPE (crosslinked polyethylene), and the DC resistivity of Hifax is larger than that of XLPE and oil-impregnated paper insulations. The electrical stress coefficient of resistivity of Hifax wire insulation increases with temperature, which needs to be taken into account in calculating the electrical field distribution across DC cable insulation. It has been observed that there is an anomalous change in resistivity at high electrical field, suggesting charge trapping and detrapping processes are present in Hifax cable insulation. It is concluded that blending Hifax with 62% polypropylene decreases the breakdown strength significantly.展开更多
该文使用国际大电网会议CIGRE WG D1.14推荐的多针电极系统研究了交直流电晕对高温硫化硅橡胶性能的影响。通过分析试验中的放电功率、电晕前后硅橡胶的憎水性状态、表面电阻率、拉伸强度、拉断伸长率等性能,讨论了交直流电晕、直流正...该文使用国际大电网会议CIGRE WG D1.14推荐的多针电极系统研究了交直流电晕对高温硫化硅橡胶性能的影响。通过分析试验中的放电功率、电晕前后硅橡胶的憎水性状态、表面电阻率、拉伸强度、拉断伸长率等性能,讨论了交直流电晕、直流正负极性电晕对硅橡胶性能影响的异同。结果表明:经过电晕处理,硅橡胶的上述性能均有所下降。就硅橡胶的憎水性状态和表面电阻率而言,交流电晕对硅橡胶的影响程度大于直流电晕的影响程度,直流负极性电晕的影响程度略大于直流正极性电晕的影响程度。硅橡胶的机械强度在电晕处理后有所下降,但交直流电晕处理后的硅橡胶的机械性能差异不明显。电晕场的空间电荷效应以及硅橡胶表面的电荷积累效应是导致不同电压类型的电晕对硅橡胶性能影响不同的原因;使用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)和X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)分析方法研究了硅橡胶表面化学结构在电晕前后的变化,认为硅橡胶在电晕处理前后化学结构的变化,是造成硅橡胶性能的变化的直接原因。展开更多
采用PSCAD/EMTDC建立了±800 k V/500 k V交直流混联输电线路反击耐雷水平仿真模型,讨论了杆塔接地电阻、绝缘子片数、雷电流波形、杆塔高度、避雷器变化对耐雷水平的影响,着重从分流系数的角度分析了接地电阻影响反击耐雷水平的原...采用PSCAD/EMTDC建立了±800 k V/500 k V交直流混联输电线路反击耐雷水平仿真模型,讨论了杆塔接地电阻、绝缘子片数、雷电流波形、杆塔高度、避雷器变化对耐雷水平的影响,着重从分流系数的角度分析了接地电阻影响反击耐雷水平的原因,比较了±800 k V/500 k V交直流混联输电线路和500 k V同塔双回线路、±800 k V直流线路的反击耐雷水平。理论分析表明:在交直流混联线路中,±800 k V线路的反击耐雷水平是其交流500 k V线路的2倍以上;反击耐雷水平在接地电阻为某一定值时急剧降低;交直流混联线路中,交流线路和直流线路的反击耐雷水平分别大于单独500 k V同塔双回线路、±800 k V直流线路。展开更多
文摘Extensive physical testing has suggested that polymeric material Hifax (Flexible Polypropylene)could be a promising candidate for the next generation of DC insulation. In the work presented in this paper,the DC conductivity and AC breakdown of this polymeric insulation material have been measured as a function of temperature. The results show that Hifax cable insulation has a higher AC breakdown strength than EPR and XLPE (crosslinked polyethylene), and the DC resistivity of Hifax is larger than that of XLPE and oil-impregnated paper insulations. The electrical stress coefficient of resistivity of Hifax wire insulation increases with temperature, which needs to be taken into account in calculating the electrical field distribution across DC cable insulation. It has been observed that there is an anomalous change in resistivity at high electrical field, suggesting charge trapping and detrapping processes are present in Hifax cable insulation. It is concluded that blending Hifax with 62% polypropylene decreases the breakdown strength significantly.
文摘采用PSCAD/EMTDC建立了±800 k V/500 k V交直流混联输电线路反击耐雷水平仿真模型,讨论了杆塔接地电阻、绝缘子片数、雷电流波形、杆塔高度、避雷器变化对耐雷水平的影响,着重从分流系数的角度分析了接地电阻影响反击耐雷水平的原因,比较了±800 k V/500 k V交直流混联输电线路和500 k V同塔双回线路、±800 k V直流线路的反击耐雷水平。理论分析表明:在交直流混联线路中,±800 k V线路的反击耐雷水平是其交流500 k V线路的2倍以上;反击耐雷水平在接地电阻为某一定值时急剧降低;交直流混联线路中,交流线路和直流线路的反击耐雷水平分别大于单独500 k V同塔双回线路、±800 k V直流线路。
