A time-domain method to calculate EMP coupling of buried cables based on transmission line model

The analysis of the EMP coupling to buried cables is important in EMP protection. Based on the Agrawal model of transmission line and the 1-D FDTD method, this coupling problem is studied. A linear fitting method is proposed to avoid the complicated convolution between ground impedance and transmission line voltage/current. The basic theory and calculation result of the method are introduced. A simple approach is provided to analyze the transmission line model in time-domain considering ground impedance. Comparison of the time domain and frequency domain calculation results shows the proposed method is effective and can solve the coupling problem in non-uniform environment where the frequency domain method does not work.