This paper presents the theoretical and experimental study of the negative corona inception voltage of the ionized conductor on the three electrode system in air. The proposed three-electrode system modifies the usual two-electrode system implemented in the filtration process by entering a supplementary cylinder free to move in x-y directions. The three-electrode system is constructed to regulate the field distribution on the surface of the ionized conductor and on the ground plate besides changing the corona inception voltage. The negative corona inception voltage is determined according to the principle developed for the forming of the recurrence of negative corona current pulses in the near vicinity of the stressed conductor. The computation of the free space charge field is determined using the charge simulation technique with the aid of the genetic algorithms. The obtained field values are harnessed in the negative corona inception voltage computation of the ionized conductor. Experimental measurements of the negative corona inception voltage of the ionized wire are carried out. The effect of moving the supplementary cylinder in both directions on the inception voltage is determined theoretically and experimentally. The results showed the effectiveness of the supplementary cylinder on controlling the inception voltage level upon the ionized conductor. The calculated inception voltage coincided in an acceptable way with those measured in the laboratory.