Digital Signal Processor Based Device for Measurement of Return Stroke Currents of Lightning Strikes to Tall Structures: First Experimental Results

This article describes the features of a device developed for measurement and recording of waveforms of first return stroke currents of lightning flashes striking tall grounded structures. The operation of this device is based on the detection of the voltage induced along a loop by the fast-varying magnetic field produced by the current flowing along the structure close to the device. A digital signal processor supports the data acquisition. The device includes means for remote internet access, self-test, and data transfer. Preliminary laboratory tests consisting of the measurement of impulsive currents intended to resemble first return stroke currents, using both the device and a reference measuring system, were performed. They allowed the analyzing of the source of differences and improving the system performance. After that, the device was installed at Morro Cachimbo Station, Brazil. The waveforms of three first return stroke currents have been recorded since then and the results showed to be consistent with those obtained by the accurate measuring system of the instrumented tower. The application of a network of this low-cost device is worth developing the regional database of lightning current parameters, and providing ground-truth references for calibrating lightning locations systems.