Experimental analysis of the strands breaking characteristics of optical fibre composite overhead ground wire due to simulating lightning strike

Abstract

With the increasing application of OPGW (optical fibre composite overhead ground wire) in power systems, the strands in OPGW are frequently broken due to lightning strikes. In this study, ten kinds of OPGW lightning-strike tolerance was tested according to the IEC standards. The influences of the following factors, such as transfer charge, tensile force, the diameter and material of OPGW outer layer strands, were analysed. The transfer charge and tensile force are positively proportional to the degree of lightning strike damage to OPGW. The diameters of OPGW outer layer strands are positively related to the lightning strike tolerance of OPGW. Compared with OPGW with aluminium alloy outer layer strands, lightning strikes tolerance of OPGW with aluminium clad steel (AS) outer layer strands is better. It suggested that the OPGW outer layer strands diameter >3.2 mm and with AS outer-layer strands shows good lightning strike tolerance. The mechanism of OPGW strands breaking was also analysed by the infrared detection, micro-morphology detection and energy spectrum. The experimental results of this study provide significant data support for OPGW type selection for lightning protection.