In the case of vertical grounding electrode dissipating impulse current

different development directions of the soil discharge channel have different effects on the distribution of electromagnetic field

resulting in different degrees of shield induced currents and port interference voltages in nearby two-ends grounded secondary cables. In order to effectively predict the interference level

a numerical method for impulse interference is proposed considering the channel development direction. Firstly

using the A-φ equations finite element method and the equivalent circuit model of secondary cable core and sheath

the frequency domain characteristics of the induced current and the interference voltage are calculated. Based on the transient electric field distribution

the soil discharge channel is reconstructed and the accurate analysis of the interference voltage considering the influence of discharge channels is achieved through time-frequency domain alternative calculation. Next

a channel observation and interference measurement experimental platform using X-ray imaging technology is established. The measured results are similar to the simulation results in waveform

with amplitude error within 12.5%

demonstrating a certain degree of simulation accuracy. Finally

simulations reveal that when discharge channels run parallel to secondary cables

the induced port voltage reaches 1.7 times the perpendicular case.This implies that specific directions channel of the soil discharge markedly amplify impulse interference. Thus

accounting for channel orientation is necessary for grounding system EMC analysis.