MidAmerican Energy Multi Value Projects 3&4

These projects were approved by the MISO Board of Directors in 2011, to increase reliability and provide for new renewable generation in this part of the country. The project consisted of 192 miles of 345kV, 161kV and 69kV single and double circuit rebuilds, new line and retro-fit projects to upgrade the existing transmission lines. As part of an Engineer-Procure-Construct team (Mastec/EC Source), with teams working from Texas, Arizona, and Iowa, M&S Engineering provided detailed transmission line design, structure design, surveying, inspection and construction management for these projects. The project was executed in four segments and utilized 1066 tubular steel pole structures. Due to the loads created by heavy ice and high winds, special attention was given to the v-string insulator design in order to minimize uplift/compression under high wind conditions without requiring oversized insulators to accommodate the heavy ice. MidAmerican preferred a damper free design for the twisted-pair conductor (T-2). This required significant research into the vibration performance of twisted-pair conductors in order to determine an acceptable design tensions that would not require dampers to avoid potential aeolian vibration.
M&S deliverables included PLS-CADD models, structure and material performance specifications, plan and profiles, staking tables, OPGW splice plan, stringing charts, phasing diagrams, bill of materials, structure framing drawings, and electrical studies.

This is the start of a successful relationship