On the influence of measuring instruments bandwidth limitations on the inferred statistical parameters for lightning currents

We present a general methodology to investigate potential effects on the statistical assessment of lightning current parameters due to bandwidth limitation in measuring systems. The proposed methodology is illustrated starting from pure log-normal distributions for current peak and risetime and assuming different upper frequency bandwidths for the measuring system (250 kHz, 500 kHz and 1 MHz). It is shown that, depending on the cutoff frequency of the measuring system (assumed to be a low pass filter), the resulting statistical parameters can be significantly affected.