Characteristics of ionization near the submerged ground rod

초록

This paper describes ionization phenomena to simulate underwater discharge at the submerged ground rod stressed by impulse voltage. Ionization parameters are analyzed in different water resistivities and applied voltages between hemispherical water tank and grounding electrode. The ionizations are decided by the appearance of discharge luminous image and variation of the I-V curves and transient impedance. As a result, the pre-ionization resistances are almost indifferent with current magnitude. On the other hand, the post-ionization resistances are in inversely proportion to second current peaks and the decreasing rates in higher water resistivities are much higher than those in lower water resistivities. The times to ionization and second current peaks are getting short in increasing voltage. When the ionization appears around the grounding electrode, I-V curves form hysteritic loops and transient impedances are rapidly decreased.