The measurement of surge voltages on transmission lines due to lightning

This paper, after referring to the work of previous investigators in the application of the photographic Lichtenberg figures to the measurement of surge voltages, describes results of additional work in this field by the authors. Laboratory calibrations of photographic Lichtenberg figures, using the cathode ray oscillograph and the lightning generator, are shown. Data are presented relative to the accuracy obtainable with these figures as a means of measuring surge voltages. An extension of instrument design is described in which two recording elements are used to give greater certainty of result. Means for connecting a surge voltage recorder instrument to a transmission line by an insulator-string potentiometer are described, and calibration of the instrument with potentiometer is given up to 1400 kv. Specimen field records of surge voltages up to 2000 kv. are shown.