Southwestern was concerned that the project might require numerous structure replacements to meet clearance requirements and address potential structural failures associated with larger capacity conductors. Barr's team conducted a thorough analysis, which included an advanced composite core conductor study as well as PLS-CADD and TOWER analyses of the transmission line.Conductor studyOur research looked into advanced transmission technologies (ATT)—infrastructure, hardware, and software options that increase transmission line capacity—and identified an aluminum conductor composite reinforced (ACCR) conductor, a specific type of transmission wire that met all specifications for the line. Not only did the new ACCR double the electrical capacity of the line, it also had more favorable physical properties and sagged less than the existing aluminum conductor steel-reinforced cable (ACSR) conductor. This innovation allowed us to maintain the existing structures, requiring only a few minor structural reinforcements, which significantly reduced project costs.Crossing the Arkansas RiverA significant challenge was designing the line to span the 2,695-foot-wide Arkansas River. Due to the span length and the required marker balls, the OPGW needed to be much stronger than the rest of the line. Accommodating the different OPGWs while balancing tensions to prevent increasing differential loading was a challenge. The wire selected for this span met the OPGW-to-conductor separation requirements and conductor-to-Arkansas River clearance standards.Substation fiber optic upgradesTo facilitate the addition of the OPGW on the transmission line, fiber optic cable was required at the Dardanelle substation. We used existing drawings and a site visit to identify the need for additional fiber optic communications infrastructure.Barr successfully completed the design phase in 2023, and construction is underway. This project was originally intended to be a two-phase project due to structural replacements and upgrades. By effectively using ATT through the chosen ACCR conductor and optimizing designs, we enabled Southwestern to execute this upgrade as a single project, avoiding the complexities and costs associated with multiple-phased projects.