Time-domain analysis of transient electromagnetic field generated by aerial busbars above lossy soil

Based on multiconductor transmission lines (MTLs) and the antenna method, a hybrid method is proposed to analyze the transient electromagnetic fields due to the operation of switches in substations. The method is valid in either near or far field. At first, the wave process along the busbars is calculated by using the finite-difference time-domain method. Then the field is calculated by using electrical dipole theory. In order to take the effect of lossy soil into consideration with reason, the closed-form of the generalized Sommerfeld integral is calculated by using generalized pencil-of-function and an equation derived from the Sommerfeld identity, which saves much time. After a model of busbars in a 500-kV substation is set up, the transient electromagnetic field is predicated.