Degradation assessment of in‐service aerial bundled cables in coastal areas leading to prognosis using infrared thermography

Abstract Of late, cross‐linked polyethylene insulated aerial bundled cables have replaced conventional copper conductors being resistant to electricity pilferage, offer lower maintenance costs and reduced power losses. However, in coastal areas, aerial bundled cables experience frequent insulation breakdown causing sudden cable failures leading to unexpected power shutdowns. Condition monitoring, employing sophisticated diagnostic techniques, has thus become a major requirement of the energy sector. The reported research work utilizes infrared thermography as one such candidate NDT technique. A novel framework is proposed to investigate the progressive shift in the statistical parameters of the temperature distribution in aerial bundled cables’ insulation, as it degrades over time. The cumulative distribution function of pixel intensity data from a healthy/ operational aerial bundled cable is first compared with a reported failed aerial bundled cable. A prominent difference in 0.9 cumulative distribution function values is observed in the temperature distributions. Therefore, 0.9 cumulative distribution function values are used for degradation quantification with respect to ageing. Degradation rates are then computed using periodically acquired thermographic data from operational aerial bundled cables, installed at two different locations in a coastal region, each subjected to different marine climate. The proposed technique proved effective in degradation rate assessment of insulation of operational aerial bundled cables. Consequently, the results achieved can also be utilized for remaining useful life prediction of these cables.