Interaction of electromagnetic fields from cloud and ground lightning flashes with an artificial low-voltage power installation

In most of the studies dealing with electromagnetic field interaction between nearby lightning flashes and electrical installations, the cloud flashes are assumed to play an insignificant role. However, our studies show that cloud flashes can generate induced voltages with amplitudes comparable to those of ground flashes when the electrical installation has a limited size or length and the lightning flash is a few tens of kilometers away. Furthermore, the voltages generated by cloud flashes have much shorter risetimes and pulse widths than those of ground flashes. This paper presents the results of a study conducted to investigate the coupling mechanism between lightning electromagnetic fields from both cloud and ground flashes and an artificial low-voltage power installation (LVPI). In the experiment, a Y-shaped artificial LVPI was constructed and exposed to lightning-electromagnetic fields. In the experiment, both the vertical electric field and the induced voltage in the LVPI were measured simultaneously. The analysis was conducted in the time domain by using the Alternative Transient Program-Electromagnetic Transient Program (ATP-EMTP) and the horizontal electric field at the installation was calculated by applying the concept of wavetilt to the measured vertical electric field. A reasonable agreement between the measured and simulated induced voltages was found. However, the results given in this study might not be true for longer structures such as power distribution lines and close lightning flashes.