Testing lightning-flash counters with step-function voltages

The lightning-flash counter sponsored by CIGREÉ is normally tested with sinusoidal alternating voltages at three frequencies: 100, 500 and 2500 Hz. An alternative method of testing with step-function voltages is proposed. It is shown that this method is simpler to carry out, both in the laboratory and in the field, and a design for a suitable signal source is presented. As lightning-flash counters of the CIGREÉ type are intended to respond to the sudden positive-going changes in the elctric field caused by lightning flashes to ground, it is claimed that the step-function-voltage test is more appropriate than the sinusoidal-voltage test, and thet more consistent results may be obtained if the step-function-voltage test is adopted.