Upgrading and refurbishment of an energized transmission line

The paper presents the executive procedures and the solutions adopted for special situations, utilizing techniques of work with energized lines-bare hand and hot stick-to upgrade and refurbish to 138 kV, a transmission line (TL) that operated at 69 kV. This TL is located in the industrial area of the Metropolitan Region of the city of Curitiba (RMC), in the state of Parana, Brazil, and radially supplied a cement factory, at a voltage of 69 kV. The electric power required by this factory is amongst the twenty biggest of COPEL (Parana State Utility). The live line work consisted in changing the existing cross-arms, initially designed to operate at 69 kV, to a new cross-arm specifically designed for this application. When there was not enough excess clearance of cable-to-ground for the new voltage level of 138 kV, a configuration was developed in which the concrete cross-arm was substituted by three insulated horizontal-vees. The interruption of energy supply to the cement factory during the construction period would make it impossible to proceed with the production of 37500 tons of cement, which would cause losses of the order of US$ 3,750,000.