电缆-架空线混合输电线路的故障暂态行波具有复杂多变的传播特性。通过理论分析和仿真验证,深入研究电缆-架空线混合线路故障暂态行波的产生机理及传播特性。并基于此阐明混合线路的单双端组合行波测距原理,详细探究了过渡电阻、故障初...电缆-架空线混合输电线路的故障暂态行波具有复杂多变的传播特性。通过理论分析和仿真验证,深入研究电缆-架空线混合线路故障暂态行波的产生机理及传播特性。并基于此阐明混合线路的单双端组合行波测距原理,详细探究了过渡电阻、故障初始相角、故障类型、故障距离对混合输电线路故障电压行波、电流行波的传播特性及组合行波测距精度的影响。同时计算分析了电缆金属屏蔽层单端接地线上的故障电流随故障距离的变化关系。过渡电阻、故障初始相角、故障类型对220 k V电缆-架空线混合线路的故障电压行波、电流行波幅值有显著影响,但对行波的第一个波头到达线路两端所需时间无影响。不同故障位置下,混合线路故障行波的幅值及第一个波头到达两端所需时间不同。电缆金属屏蔽层采用单端接地方式时,电流行波幅值随电缆故障距离增大呈非线性单调递减的特性。展开更多
Thin metal sheets are often located in the coupling paths of magnetic coupling energy transfer(MCET) systems. Eddy currents in the metals reduce the energy transfer efficiency and can even present safety risks. This p...Thin metal sheets are often located in the coupling paths of magnetic coupling energy transfer(MCET) systems. Eddy currents in the metals reduce the energy transfer efficiency and can even present safety risks. This paper describes the use of etched fractal patterns in the metals to suppress the eddy currents and improve the efficiency. Simulation and experimental results show that this approach is very effective. The fractal patterns should satisfy three features, namely, breaking the metal edge, etching in the high-intensity magnetic field region, and etching through the metal in the thickness direction. Different fractal patterns lead to different results. By altering the eddy current distribution, the fractal pattern slots reduce the eddy current losses when the metals show resistance effects and suppress the induced magnetic field in the metals when the metals show inductance effects. Fractal pattern slots in multilayer high conductivity metals(e.g., Cu) reduce the induced magnetic field intensity significantly. Furthermore, transfer power, transfer efficiency, receiving efficiency, and eddy current losses all increase with the increase of the number of etched layers. These results can benefit MCET by efficient energy transfer and safe use in metal shielded equipment.展开更多
文摘电缆-架空线混合输电线路的故障暂态行波具有复杂多变的传播特性。通过理论分析和仿真验证,深入研究电缆-架空线混合线路故障暂态行波的产生机理及传播特性。并基于此阐明混合线路的单双端组合行波测距原理,详细探究了过渡电阻、故障初始相角、故障类型、故障距离对混合输电线路故障电压行波、电流行波的传播特性及组合行波测距精度的影响。同时计算分析了电缆金属屏蔽层单端接地线上的故障电流随故障距离的变化关系。过渡电阻、故障初始相角、故障类型对220 k V电缆-架空线混合线路的故障电压行波、电流行波幅值有显著影响,但对行波的第一个波头到达线路两端所需时间无影响。不同故障位置下,混合线路故障行波的幅值及第一个波头到达两端所需时间不同。电缆金属屏蔽层采用单端接地方式时,电流行波幅值随电缆故障距离增大呈非线性单调递减的特性。
基金supported by the National Natural Science Foundation of China(No.51125028)the National Key Technology R&D Program of China(No.2011BAI12B07)
文摘Thin metal sheets are often located in the coupling paths of magnetic coupling energy transfer(MCET) systems. Eddy currents in the metals reduce the energy transfer efficiency and can even present safety risks. This paper describes the use of etched fractal patterns in the metals to suppress the eddy currents and improve the efficiency. Simulation and experimental results show that this approach is very effective. The fractal patterns should satisfy three features, namely, breaking the metal edge, etching in the high-intensity magnetic field region, and etching through the metal in the thickness direction. Different fractal patterns lead to different results. By altering the eddy current distribution, the fractal pattern slots reduce the eddy current losses when the metals show resistance effects and suppress the induced magnetic field in the metals when the metals show inductance effects. Fractal pattern slots in multilayer high conductivity metals(e.g., Cu) reduce the induced magnetic field intensity significantly. Furthermore, transfer power, transfer efficiency, receiving efficiency, and eddy current losses all increase with the increase of the number of etched layers. These results can benefit MCET by efficient energy transfer and safe use in metal shielded equipment.
