Lightning stroke attachment characteristics of a covered conductor and a bare conductor on power distribution lines

Experimental studies were carried out on the discharge characteristics of a rod-bare conductor gap and a rod-covered conductor gap up to 3 meters. 50% flashover voltage of a rod-covered conductor gap is higher than that of a rod-bare conductor gap under negative impulse voltages. These effects become so notable as the insulated part of a covered conductor is thicker. Measurement using ALPS shows that development of an upward leader from an covered conductor is suppressed by the insulated part of a covered conductor