直流电晕笼中的合成场强和离子电流的计算

为了更好地解决高压直流输电线路中电磁环境问题,需要研究高压直流线路的电晕特性,而电晕笼是研究导线电晕特性的重要实验设备。因此,采用有限元法和通量管法分别求解了电晕笼内单极导线结构的电场和空间电荷密度,提出了电晕笼中导线表面空间电荷密度初值计算公式。计算中考虑了导线周围电离层的影响,并根据最小临界电离电场计算出一个电势作为新的边界条件。通过对比电晕笼内部的电晕电流、电场和离子电流密度分布的计算和测量数据,验证了算法的有效性。

Resultant Electric Field Gradient and Ion Current in DC Corona Cage Solved by the FEM Method

This paper deals with monopolar corona discharge in wire-to-cage geometry. Electric field is solved using the finite element method (FEM), and the current continuity equation which upgrades the space charge density around the conductor is solved using the method of flux-tube. The ionization region and the related potential decrease which is usually neglected are considered as the Dirichlet condition in FEM method. Total corona current, electric field at the ground with the presence of space charge and current density at the ground under different applied voltage are calculated. The experimental data are executed in a small corona cage. The electric field and the current density near the ground are measured by compound electric field instrument and Wilson plate respectively. The numerical results are in agreement with the experimental data.