Page 65 - North American Clean Energy May/June 2020 Issue

1. Ownersthatareintheprocessof building new sites or upgrading existing ones would be advised to ensure your overhead line structures are designed to the wind and ice loading requirements of ASCE 74. This will result in stronger, more resilient structures in your balance
of plant system. Many sites only design to the minimum NESC “safety” standards which are woefully inadequate as design criteria for extreme weather events.
2. Nomatterthematerialforthe
poles and towers, ensure they
are specified to be designed to a “minimum” strength. Did you know wood poles are typically specified as a “mean” strength, while steel and concrete poles are typically specified to a “minimum” strength?
3. Makesureyourpurchase specifications are current and appropriate for the new project. A proper specification must identify the right materials for the probabilistic severe weather events expected (wind/ice). Your specifications should also address quality assurance protocols for how to properly design, fabricate, and install such infrastructure. Manufacturing defects in steel poles or towers can make them susceptible to fatigue
and failure during severe weather and high wind events. With the right quality assurance program, this risk can likely be avoided.
4. Forsitesalreadybuiltandinservice,a thorough asset management plan that involves a structural review of your infrastructure (not just electrical) is critical. If you know that your assets were under designed or built with
little to no safety factors, modify your preventative maintenance strategy to take these weaknesses into account. Conduct more regular and detailed inspections to identify potential issues that may fail during a storm. If you have steel poles in your system, inspect them for corrosion issues or fabrication defects that might adversely affect the performance of your transmission line.
5. Your asset management strategy should also include a detailed storm response plan. Be ready to conduct drone inspections on the line following a storm to document even the smallest of defects that could prove significant to restoration efforts. Make sure that whoever is evaluating that data has a strong understanding of structural matters in addition to electrical matters. Consider having a safety stock of poles and structures on hand to replace failed components quickly, removing the risk of longer lead times and potential prices hikes for emergency product.
Unfortunately, there is nothing we can do to change the weather that impacts our renewable energy assets. However, there are plenty of proactive steps that owners, operators, and developers can take to mitigate these risks and improve the overall reliability and performance of our operations. When something as small as a single loose or missing cotter pin can take an entire site offline, it stands to reason that we should be taking greater care in the way we design, build, and maintain our balance of plant and transmission infrastructure so that our assets can stand up to the worst mother nature has to offer.
Grant Leaverton is Senior Account Manager at Exo, a U.S.-based company that has over 100 years of experience of infrastructure inspection, evaluation, remediation, and manufacturing.
EXO /// exoinc.com
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