Lightning transient sensing, monitoring and application in electric power systems

Lightning faults in transmission lines are randomly distributed throughout the power system. The associated electromagnetic transient characteristics are intricate and hold significant importance for effectively pinpointing lightning faults, as well as identifying fault types crucial for the power system's lightning protection design, operation, and maintenance. This advantage has been evident with the application of protection units or lightning location systems (LLS) over the past decade. However, the rapidly evolving landscape of high-voltage direct current (HVDC) transmission lines and the accelerated integration of renewable energy are contributing to the increasing complexity of modern power networks. These networks now encompass AC transmission, DC transmission, AC-DC hybrid transmission, and more. Protection units are typically installed in substations, capturing transient current signals with lower sampling frequencies. Consequently, grid operators determine the lightning strike point within a few spans by computing the flashover location. In traditional LLS measurement, the indirect measurement of the electromagnetic field and the adoption of the time difference of arrival (TDOA) method are used to retrieve lightning locations. Under these circumstances, accurately identifying fault types becomes challenging, obtaining transient characteristics along transmission lines and substations is elusive, and the precision of lightning surge waveforms requires further enhancement. Furthermore, distribution networks present additional challenges due to the numerous branches and feeders, making lightning transient measurement to be more difficult.