Measuring low-current discharges from grounded rods under high background electric fields

This work presents the development of an inductive current sensor for measuring pulsating corona discharges observed under high background electric field. Laboratory and field experiments in different setups are used to corroborate the discharge features. The first location is on the roof of a regular building, and the second is on a flat area. Due to the enhancement of the E-field caused by lightning strikes in the vicinity of a grounded rod with a sharp tip, positive and negative pulses before or after the strikes are observed. When lightning activity is far from the structure, but the electric field remains high, pulses are also observed. Finally, one prototype of this sensor was modified to work as a pulse detector with a higher current threshold, allowing detections of leader currents above 0.5 A. The sensor performance is validated in the laboratory and investigated in the field, in association with lightning events.