Development of a system for measuring lightning voltage waveforms on insulator strings for 500 kV overhead transmission lines

The development of a system for measuring lightning voltage waveforms on insulator strings during lightning strokes on a power-transmission line now used in commercial service is described. The system uses a quick-response noise-immune optoelectronic sensor. The high-speed voltage-measuring system combines an optical Pockels sensor having high-insulation characteristics, low noise, and quick response with a microcomputer and digital oscilloscope so as to achieve high data-collection efficiency. It is mounted on an insulator string on an operating 500 KV power-transmission line to observe the high-voltage waveforms during lightning surges. Experiments have verified that voltage waveform measurements of excellent accuracy can be made, and these can be used to elucidate the phenomena leading to flashover during lightning strokes. It is possible to make simultaneous multiphase measurements during the lightning strokes