Convergence and symmetry of capacitance matrix of dielectric-coated cable bundles above the ground based on the moment methods

Using the analytical method to calculate the capacitance matrix has its limitations. Numerical method provide a viable way. The moment method is the most classical numerical method. In this paper, the method of moments is applied to calculate per-unit-length capacitance matrix for dielectric-coated cable bundles above the ground. Two necessary criteria are presented for match-point selection. The number of Fourier coefficient and match-point on the conductor boundary is investigated to illustrate its influence on convergence and symmetry of the capacitance matrix. The results show that the matrix is more convergent and symmetric as the increase in the number of Fourier coefficients (equal to the number of match-points) which represented for the distribution of charge around the surface. The sufficient and effective match-point distribution scheme which not only guarantees the convergence of the capacitance but also the symmetry of the matrix with an acceptable error is five expansion coefficients allotted to conductor surface and eight coefficients allotted to dielectric surface.