Inception of impulse corona from Franklin rods

A setup which simulates the cloud and the initiation of upward leaders from Franklin rods in the laboratory is described. It is used for studying the time to inception, T₀, of first corona from earthed Franklin rods and from Franklin rods energized by a pulse voltage. In one series of experiments, the Franklin rod was earthed and the T₀ of the impulse corona was measured using a storage oscilloscope. In another series of experiments, the Franklin road was energized by a negative square pulse of 20 μs duration. The application of the square pulse was synchronized with the negative surge simulating the downward leader. The amplitude of the square pulse was high enough to initiate a streamer at the tip of the rod. The effect of energizing the Franklin rod on T₀ is studied