Welding Failures Putting Your Wind or Solar Farm at Risk?
Are deficient welds putting your wind or solar operation at risk? If you own and manage your own stretch of HV transmission line that contains steel poles, chances are the answer is yes. Over the last five years, Exo has investigated numerous transmission line failures which were caused by welding failures. Many of these failures occurred on “gen-tie” transmission lines owned and operated by the site owner, not the local utility company.
Several trends have emerged and subsequently converged to make a “perfect storm” of sorts for structural welding issues in high voltage transmission structures. Those trends can be simplified to the following:
- The rapidly expanding tower fabrication footprint beginning in 2005 created training and staffing shortfalls that resulted in quality escapes (most notably welding defects), leaving the facility unbeknownst to construction and project engineering teams.
- Steel is not what it used to be! As more recycled material is utilized at US mills, steel becomes stronger, harder, but also more brittle. Brittle steel is extremely susceptible to cracking during cutting, forming, and welding.
- Engineering designs have changed. Gone are the days of excessive safety factors. Overdesign makes for heavy, expensive structures, so engineers are optimizing their towers to eliminate as much weight (and cost) from their products as possible. This is fine if you can produce a product perfectly 100% of the time during fabrication. Unfortunately, that is simply not possible. See trends 1 and 2!
Because of these three driving factors, we have seen an alarming increase in defective welds and cracks in formed products appearing mostly in structures produced within the last 12-15 years. In fact, over the last several years, Exo has inspected more than 40,000 transmission assets built by ten different fabricators, of which 61% were considered high-risk.
Now is the time for wind farms to take action against these risks, and one way to do so is by prioritizing weld inspections during wind farm maintenance. This is an often overlooked area, as most wind farm operators are not aware of the systemic issues lurking in their structures, nor do they have the expertise to address such issues.
What to Know About Wind Farm Weld Inspection
Where Should You Inspect?
The first thing you need to know is what to inspect on your wind farm. Weld inspections are pertinent and necessary on structural steel equipment in your substations, transmission lines, and even the structural towers/pedestals for your turbine generators. Here’s what you should look for on each:
- Balance of Plant: Any wind farm utilizing galvanized tubular steel in their balance of plant (substation dead ends or transmission line) is at risk for catastrophic failure due to weld defects. Wind-induced vibration from vortex shedding is also exacerbating the problem since transmission structures are not designed to account for fatigue cycles.
- Turbines: Although the design criteria and welding methods for turbine structural towers are a bit different than utility transmission towers, they are not immune to the trends listed above. In fact, there have been a number of manufacturing weld defects that have affected the industry over the last 10 years.
- Unmanned aerial vehicle (UAV) technology is a powerful new tool to help owners visually inspect their system in a safe and cost-effective manner. Exo recommends using UAV inspections regularly as part of a preventative maintenance program to create baseline health records of your assets. With drone inspections, you can get a more thorough idea of your asset without risking anyone’s safety. Should the baseline indicate any kind of surface level weld defect or other structural issue, a more targeted, hands-on NDT inspection can be performed as needed to fully assess the system’s damage and potential risk.
Benefits of a Lifecycle Management Approach
Wind farm maintenance and inspections are a critical aspect of a lifecycle management approach to your assets. Rather than reacting to structural failures, do the work now to prevent them from occurring in the first place. Proactive inspection and maintenance costs are usually much cheaper than the cost of an unexpected failure and resulting sitewide outage. By performing conditional assessments of fracture critical welds on your HV transmissions structures and turbines, you’ll be aware of potential issues early on and can appropriately monitor and remediate them before they become too costly.
At Exo, our Ex-Tend data-driven lifecycle management approach informs everything we do. When we conduct weld inspections as part of your wind farm maintenance program, we provide the information you need to make strategic decisions that will prolong your asset’s lifespan. This can lead to significant cost savings, reduced risk, and improved business operations overall.
Ready to Work With Us?
Our team would love to talk to you, so we can learn about your wind farm goals and primary areas of concern. Contact us today, and we’ll help you take the first step in creating a comprehensive lighting asset management program. Give us a call at 281-259-7000.