Development and Installation of BPA´s New Generation Transmission Conductors

The Bonneville Power Administration (BPA) has developed a family of new generation conductors which promises to reduce transmission line life-cycle costs. These trapezoidal wire conductors reduce air void area by 80 percent over conventional round rod conductors, allowing a denser packing of conducting material and greater efficiency through increased conductance and/or reduced tower loads. The trapezoidal wire family is made up of nine conductors ranging in size from 1.0 to 1.8 inches; six are all aluminum and three are aluminum with steel reinforcement. The new conductors are expected to satisfy all of BPA´s typical conductor requirements for new construction, rebuild, and reconductoring projects, where the economics of resistive losses dominate the design. This paper introduces the new conductor family and assesses its uses and limitations. It discusses design details; mechanical, stress-strain, creep, and self-damping characteristics; and conductor sizing, procurement, handling and sagging, savings, and lattice steel and wood pole applications. It also describes the first use of the trapezoidal wire conductor family on the BPA Boundry Integration/Reinforcement Project.