Observation and analysis of multiple-phase grounding faults caused by lightning

This paper describes four phase and five-phase grounding faults caused by lightning on a 154-kV overhead transmission line. The authors measured insulator voltages and currents flowing along the ground wire and the tower. In addition, they photographed lightning strokes to the transmission line and flashovers between the arcing horns and examined the fault phases at substations. The paper analyzes insulator voltage waveforms using the Electromagnetic Transients Program (EMTP) and estimates the fault processes.