On the Return Stroke Initiated From the Attachment Point Considering Current Reflection From the Ground

In this article, we present an analysis of electric fields and derivative waveforms radiated from lightning return stroke in the presence of an attachment point above the ground. Return stroke initiated from the ground (RSG), return stroke initiated from an attachment point above the ground (RSAP), and return stroke initiated from the attachment point considering current reflection from the ground (RSAPR) were considered and compared. Both first and subsequent return strokes were included in the simulation. It is shown that the presence of the attachment point results in a noticeable initial sharp peak on the electric fields and the derivative waveform was characterized by larger positive peak and negative overshoot. Both the electric field and derivative waveforms in RSAPR were much similar and closer to the results from RSG due to the current reflection from the ground. The influences on the electric fields and derivative waveforms were also discussed, including velocity of upward and downward wave, the attachment point height, reflection coefficient from the ground, and wave velocity of the reflected wave. The simulated results were also compared to the measured fields.