rPatrick Harkin, Associate Vice President & Group Lead of Engineering, ASEC Engineers a Verdantas Company
Scope:
This project aimed to conduct an economic feasibility study on a set of high-strength, insulated cross-arms, designed for use in transmission towers and monopoles. ASEC’s role was to perform a detailed analysis of the product’s performance under various span configurations typical of transmission lines in the Midwest U.S. The study involved running a series of PLS-CADD models to compare the cost-effectiveness and performance of these products against conventional transmission designs. The spans analyzed ranged from short to exceptionally long, with the study focusing on a five-mile stretch to ensure the statistical reliability of the results.
Challenges:
One of the significant challenges in the study was the strength of the insulated cross-arms, which were far more robust than typical transmission components. This overperformance caused the products to fail at unusually high load levels during initial testing. To address this, ASEC adjusted the base design assumptions by increasing the load conditions to simulate more severe environmental scenarios, thus providing a more accurate representation of how the products would perform in real-world conditions. Additionally, despite these adjustments, the strength of the products presented difficulties in obtaining the expected data points. As a result, a secondary study was conducted to determine the line angle tolerance of the strongest insulators under typical span conditions.
Outcome:
The study resulted in a comprehensive comparison of approximately 40 to 50 design iterations, analyzing both traditional transmission components and these specific products. The economic assessment covered multiple configurations, from typical monopoles and towers using traditional materials to designs incorporating these innovative products. Key findings included:
- A detailed cost-per-mile analysis for both traditional and these innovative solutions.
- Identification of span ranges where monopoles became less economical compared to towers, and vice versa, for both traditional and these new designs.
- Insights into the performance of the new products in terms of phase compaction, which reduces pull height and has cost-saving implications during construction and installation.
- A detailed understanding of how changes in span lengths and design assumptions impact the overall cost and efficiency of the transmission line.
The final result provided the manufacturer with a clear understanding of the economic benefits of using their products in different transmission line configurations and environments, guiding future product development and market positioning.
Value Adds by ASEC:
- Industry Expertise: ASEC leveraged its extensive historical knowledge of transmission line design in the Midwest, including common practices for material selection, structural arrangements, and foundation types. This enabled the team to create realistic baseline models for comparison, ensuring the study was grounded in actual industry practices and providing a clear context for Shemar’s products.
- Data Validation and Economic Modeling: ASEC sourced recent cost data from a publicly available report from a major Investor-Owned Utility (IOU), which provided current figures on construction and material costs post-COVID. ASEC’s team used this data to develop unitized costs for construction, equipment, and labor, incorporating it into the PLS-CADD models to generate accurate cost-per-mile estimates for both traditional and these innovative solutions. Additionally, ASEC’s industry contacts provided valuable insights into labor costs, foundation installation, and crew efficiencies, filling gaps left by the public report and refining the accuracy of the cost estimates.
- Comparative Cost Analysis: ASEC focused on comparing the relationship between traditional transmission solutions (both towers and monopoles) and these innovative solutions. The study highlighted specific conditions where the new products provided economic advantages, such as reduced tower heights due to phase compaction and more efficient use of space. The analysis also highlighted the marginal cost differences between monopoles and towers in traditional designs and provided recommendations on when to use one over the other, based on the specific geographic and environmental conditions.
- Collaborative Industry Contacts: Throughout the project, ASEC utilized its industry network to fill in gaps in the public cost report, particularly in terms of labor and materials used in Northern Texas. ASEC’s direct interactions with construction professionals allowed for the incorporation of real-time industry data, ensuring the study’s conclusions were relevant to current market conditions.
Conclusion:
This project stands out as a unique collaboration between ASEC and a manufacturer, who typically performs product validation in-house but required ASEC’s expertise to position their product in the transmission market. The partnership allowed for a novel approach to cost modeling and provided valuable insights into the economic impact of using advanced transmission products. The study ultimately allowed the manufacturer to better understand how their product could fit into the market, with a clear path forward for further development and potential applications in transmission line design.
