Controllability of arc jet from arc horns with slits

Abstract

AbstractUltrahigh‐voltage transmission lines must be protected from lightning surges and the large‐current fault arcs which follow. Horns which are installed at the jumpers on the strain towers have a role in protecting the insulators from the fault arcs by coordinating insulation strength and holding large‐current fault arcs between the horns. Although a flat surface of the electrode tip with a small diameter effectively meets these requirements, it results in the deterioration of corona discharge depressing capabilities in a steady state on power transmission lines. To improve corona discharge depressing capabilities and to reduce deflection of arc jets, finally two types of hemispherical‐shaped arc horn electrodes with slits are developed. The arc jet control performance of those horns was disclosed experimentally as follows: Two types of arc horn electrodes with our or six slits show remarkable arc jet control performance in the current of larger than 5 kA. The addition of a rod‐type central electrode at the center of the hemispherical‐shaped electrodes results in the considerable extension of arc jet controllability in the wider current zone by containing the arc spot within the tip area of the central electrodes. Based on the foregoing results, arc horn electrodes with slits have been designed and utilized for practical application.