Calculation of the Lightning Induced Response on Overhead Transmission Lines based on the Electric Field Representation Methods

The transient electromagnetic field produced by an indirect lightning can induce to overhead power lines, which may cause serious effects to the power system. When calculating the lightning induced voltages on the overhead lines with the conventional numerical method, to pursue a sufficiently accurate results, the lightning electric field at a large number of observation points along the lines should be calculated. However, since the numerical integration are commonly involved when calculating the lightning electric field, the significant CPU cost is normally required for the whole computational procedure. In order to enhance the computational efficiency, two approaches which based on the electric field representation technique were proposed. In these two methods, the lightning electric fields at several observation points along the line are calculated by using the conventional numerical method first, then the electric field along the entire line can be represented with the continuous functions by using two different fitting methods, which are matrix pencil method (MPM) and the least squares-nonlinear least squares (LS-NLS) method. As a result, the necessary number of observation points where the lightning electric field should be calculated by using the conventional numerical methods is significantly decreased. The proposed methods were validated and compared by some numerical examples.