Presentations

Abstract

SkySpecs conducted a study on managing the risk of crack formation and propagation on wind turbine blades. Around 65,000 damages were taken into account from over 137,000 inspections. We examined multiple crack risk categories and focused on medium, high, and very high-risk levels. Medium-risk cracks constitute a group of constrained damages that we typically advise should be repaired in the current season, but they often aren't addressed until the following year. High-risk cracks are recommended to be repaired as soon as possible, and very high-risk ones often require turbine shutdown due to the size of the damage and the risk of rapid propagation if operated. When analyzing cracks in turbine blades, there are two important aspects - crack formation and crack propagation. Studies into blade risks associated with cracks can't be conclusive without considering these two aspects. Our research first considered the formation rates for cracks across asset age. We found that our research reflected clear trends across certain blade sizes. The first forming rate peak varies across blade models and can be seen sooner in the largest blades. Noticeably, the absolute risks vary significantly across blade sizes, making new-generation blades more fragile assets. Another aspect we looked at is quantifying the probability of crack propagation. This involves the likelihood of risk level increases over a specific period. We looked at multiple scenarios of risk advancements over one year, two years, and beyond. Using crack's propagation probability over different sampling cadences, we measured the odds of risk increase between 1 year and two years of operation. Another finding we noticed in our research is that the size of the rotors can help us predict when faults may occur. For small rotors, the probability of damage growing is around 10% for a 2-year operational timeframe. The same consideration for large rotors results in an estimated probability of over 40%. Our research reflected clear trends across certain blade sizes. Quantifying relative risk levels across operational timeframes is a breakthrough in the field. This allows us to prepare for upcoming challenges and confidently plan budgets and repair scopes. If a wind farm has a high proportion of large blade models, it may be time to adjust the inspection schedule to account for more frequent checks of these models. This is an adjustment many in the industry must make as O&M teams start to manage bigger and bigger turbines. Quantifying relative risk levels across operational timeframes is a breakthrough in the field. This allows us to prepare for upcoming challenges and confidently plan budgets and repair scopes.