Performance tests of barriers and power line conductor guards

Tests were conducted in order to measure the 60 Hz AC breakdown voltage of small air gaps (up to 0.2 m) formed by an energized and a grounded electrode. In Phases 1 and 2 energized rod-grounded rod, and energized conductor-grounded rod gaps were studied with a flat insulating sheet (barrier) between the electrodes. In Phase 3 the energized electrode was a section of a power line conductor, the grounded electrode was either a rod or sphere, and the insulating cylinder (a 69 kV line guard) was on the conductor. The test results contribute to the understanding and evaluation of tools used for live-line work and the safety conditions associated with them.