Field experience on improving corrosion performance of OH lines crossarms and concrete poles

Tamil Nadu Electricity Board (TNEB) supplies power to about 9 million consumers through a vast distribution system consisting of over 90000 distribution transformers, 0.09 million km HV lines and 0.4 million km LV lines. Most of the distribution lines are overhead lines with aluminium-conductor-steel-reinforced (ACSR). The pole supports of these lines are of either reinforced cement concrete (RCC) or prestressed cement concrete (PSC). The crossarms are of mild steel coated with anti-corrosive paint. Breakdowns of lines are caused by conductor snapping, crossarm failure and deterioration of pole. They lead to interruptions in power supply and heavy expenditure on rectification, besides wastage of manpower as well as materials for the utility and loss of production for the consumers. TNEB took up research projects to analyse such failures, arrive at probable causes, make remedial suggestions and monitor their effectiveness to decide on the suitability. The studies have helped identification of the remedial measures that suit the TNEB for mitigating supply interruptions caused by line breakdowns on account of the premature failure of conductors, crossarms and poles