35kV三相统包冷绝缘高温超导电缆磁场数值计算

针对传统地下输电电缆已不能满足大城市未来发展的用电需求,以35kV三相统包冷绝缘高温超导电缆为例,首先对其超导电缆结构参数进行分析,计算出每层自感和互感,进而得出层电流分布;然后基于电磁物理学结合微分法推导超导电缆本体磁场逐点计算公式,根据三相超导电缆结构建立数值仿真计算三维模型;分别使用解析法、数值法对其超导电缆内部、外部磁场进行计算。计算结果表明,内部磁场分布并不均匀,最大磁感应强度位于载流层最外层;外部磁场呈负指数分布且护套层外部磁场最大值远远低于国际非电离辐射防护委员会给出的磁场强度限值100μT。

Numerical Calculation of Magnetic Field of 35 kV Three-phase Turnkey Cold Insulated High Temperature Superconducting Cable

Aiming at the traditional underground transmission cables have been unable to meet the power need of the future development of large cities.The 35 kV three-phase turnkey cold insulated high temperature superconducting cable is taken as an example.Firstly,the structural parameters of the superconducting cable are analyzed,and the self-inductance and mutual inductance of each layer are calculated to obtain the layer current distribution.Then,based on electromagnetic physics and differential method,the point-by-point calculation formula of the superconducting cable’s magnetic field is derived.The internal and external magnetic fields of the superconducting cable are calculated based on the analytical method and the numerical method.The calculation results show that the internal magnetic field distribution is not uniform,and the maximum magnetic induction intensity is located at the outermost layer of the current-carrying layer;The external magnetic field is negatively exponentially distributed and the maximum external magnetic field of the sheath layer is far lower than the magnetic field given by the International Commission on Non-Ionizing Radiation Protection that the intensity limit is 100μT.