EASi’s proactive approach helps a utility company achieve cost savings while increasing safety and reducing future risk.
The client and challenge
Our client is a community-based, not-for-profit water and energy company that delivers water and power to more than two million people living in the southwestern U.S. Within the customer’s domain, there were 80 wood and steel transmission poles that required evaluation to determine if they needed to be replaced. These poles were to be evaluated by a list of criteria set forth by the customer, including the poles’ age, conduction and current National Electrical Safety Code (NESC) loading requirements.
The EASi solution
At the start of the project, EASi performed site walks to observe existing assets and gain knowledge on the transmission line and site surroundings. The poles were identified by the client based on age, treatment type and wind/weight span analysis. Upon receipt, the EASi design team pulled/reviewed all maps and line data from the client’s system. EASi also walked the transmission line to gather additional data.
Once all inputs were collected, the existing 69kV transmission line was modeled in PLS-CADD and analyzed for structural integrity based on current NESC-C2 Grade C loading criteria. New/replacement structures were designed and analyzed using PLS-CADD/POLE based on current NESC-C2 Grade B loading criteria as well as client standards. Existing guyed structures were replaced with direct-embed or self-supporting steel structures, depending on structure loads and pole location.
EASi then documented all material information and entered it into the customer’s work management system for procurement. Permit drawings and documents were prepared for submittal by the client. All designs and drawings were performed in accordance with client standards. Line and structure design were completed using PLS-CADD and PLS-POLE. Design details and construction drawings were created using Bentley MicroStation.
After EASi’s site walk and modeling of the 80 poles in PLS-CADD, our teams determined that only 25 poles needed to be replaced with steel or wood poles, which ultimately provided significant cost savings for the client. We were also able to identify a section of the line that was not energized or providing any additional reliability to the client’s system. We determined that this section may no longer be needed, consulted the client and recommended that this section of line be removed entirely instead of replaced. This eliminated the cost of replacing eight wood poles as well as maintenance costs for the section of line.
Additionally, while performing the design for these projects, EASi developed a comprehensive PLS-POLE library of the client’s standard structures, which enabled us to decrease design time required for additional structures. Our team utilized framing and assemblies for the standardized structures, which allowed us to make modifications to structures and underbuilt attachments where necessary, with minimal added design time.
EASi’s experience also allowed us to identify potential design conflicts/changes before the project began. These were discussed with the client prior to finalizing the scope of work. Early identification of potential design issues that could impact either the design or construction schedule/cost significantly reduced the potential for costly change orders. In addition to the initial determination of poles that needed to be replaced, EASi identified structures that required special attention due to right of way (RoW) constraints. This proactive identification allowed the design team to discuss possible solutions with the client, and their impact on the design was accounted for during initial scoping. EASi also identified potential changes in the design that were less likely and discussed their potential impact with the client.
Additional key outcomes of this engagement include EASi’s enhanced safety efforts. To limit the potential for cascading structure failures, steel dead-end structures were placed into the new or existing line every 10 structures. Designing the lines to prevent or limit cascading events increased public safety and reliability of the overall system. When appropriately placed, these structures also increased worker safety by limiting their exposure to downed lines in often compromising weather conditions.
Another key safety initiative involved the fiberglass insulation of all guy wires attached to the transmission poles. The placement of guy insulator was designed so that in the event of a guy wire failure, no part of the guy that was hanging below the conductors would be energized and cause a hazard to the public or crews.
EASi’s thorough and proactive scoping of the project identified a number of areas where the client could realize significant cost savings. In addition, EASi provided adjustments to increase worker safety and reduce the opportunity for equipment failure on the long-term.