Time-Frequency and Energy Correlations of the Transient Voltages Triggered by Cloud to Cloud Discharges

This paper presents a study performed on time, frequency, and energy correlations of transient voltages generated by the cloud to cloud discharges. It revealed that the energy embedded in transient voltages have been lumped over few segments of time domain voltage profile than uniquely scattering over the time span. The study further determined that the energy concentration becomes higher in and around the vicinity of the time domain voltage maxima or minima, and such high energy-concentrated segments confined to a minute time span in comparison to the total time span of the transient voltage. The study also established that there is a small time lead or lag between the time domain voltage maxima or minima and the time of energy maximize. Moreover, the analysis deduced that the time lead or time lag phenomenon, is not sensitive to the orientation of the time domain voltage profile, but fuelled by the pulse type. The response time of surge protective devices can become crucial if the stipulated clamping voltages of the protection devices fall close to local peaks of the transient voltages.