INVESTIGATING THE INSULATION DISTANCE REDUCTION OF BARE CONDUCTORS OVERHEAD LINES DUE TO RESIDUAL EXPANSION OF STAY WIRES DURING FIRE

摘要

This work deals with theoretical and experimental investigation concerning the insulation distance reduction of distribution lines, when a stay wire (a steel wire that supports the pole of the distribution network), was heated due to ground fire occurrence. It has been experimentally proven that a ground fire can drastically reduce the mechanical strength of stay wire, up to a point that wire breakage can be caused even from a small ground fire produced by dead wood and small bushes near the wire. Theoretical results lead to the conclusion that the fire causes a permanent expansion on the wire which results in the loosening of the bare conductors.