Winter is coming... (for some it has already arrived).
Winter weather can present a few operational challenges for wind farm operators, particularly when it comes to a serious ice storm. Those of you who manage assets in cold climates are all too familiar with the issue of ice accumulation on blades and other critical components. Ice buildup and shedding can affect the surface properties of your equipment and even pose an impact threat to anything nearby. It limits the ability for operations teams to access the field and can cause outages that result in lost revenues for the owner.
But the effects of ice are not limited to the turbine generators themselves. They can wreak havoc on your balance of plant (BOP) and transmission system as well. And as we enter the peak of winter, here are a few things you need to be aware of.
What’s the Big Deal about Ice?
While snow will not cause significant harm to your structures, there are a lot of serious problems that come with ice. Wind turbines are affected by atmospheric icing which comprises all processes of ice or snow accretion on the surface of exposed objects.
There are several long-term damaging effects of in-cloud icing on wind farms, including:
- Large-scale power losses due to wind turbines being stopped to prevent mechanical damage
- Increased superficial roughness and an altered profile of airfoils, leading to severe performance loss
- Reduced life expectancy of structures as a result of component fatigue
- Safety risks for the public and employees, as well as nearby roads and facilities
- Overload due to delayed stall, which can increase the stresses on mechanical components and cause deterioration
It’s easy to see that ice and wind turbines just don’t mix; structures can lose all functionality and value in one big storm. But what about your BOP? Here, the primary risks of ice can be narrowed down the following:
- Impact damage on pad mount transformers (PMT) from ice shedding
- Conductor galloping due to high winds and ice buildup on the wires
- Structure failure due to wind and ice loads exceeding intended design load cases
A thorough inspection is always a good idea immediately following icing events. Any minor damage identified can be addressed quickly before it progresses into an expensive repair job down the road.
And while major damages will be very apparent (a crushed PMT or downed transmission lines for instance), other resulting issues could be significantly harder to spot and present just as much, or perhaps more, risk to your ongoing operations. Here are just a couple examples of issues caused by conductor galloping that would be difficult to spot from the ground, yet still present a very high risk of unplanned failure and subsequent outage.
Damaged post insulator bracket from continuous line galloping.
Damaged clevis from severe line galloping.
Failed pole due to wind and ice loads.
How to Inspect
Unmanned Aerial Systems (UAS), otherwise known as drones, have redefined how operators collect data on their infrastructure. Faster, safer, cheaper are certainly appropriate words to describe the use of drones in most cases (but not all…you must evaluate each individual situation and project). In a post-storm scenario where time is critical and you need the highest quality data to aid your decision-making process, you would do well to consider deploying this technology as part of your response.
If you include these inspections in your annual budget, you won’t be faced with unexpected costs, and you’ll already have the steps in place for responding to a storm. It is also important to pre-qualify third parties if you do not have the resources in house for this type of work. Stick to a firm that has a deep knowledge of the assets themselves. These organizations are familiar with the issues specific to a certain asset class and can help you navigate the associated risks.
That’s where Exo can help. We offer asset program management services focused on increasing the lifespan of your structures. This includes conducting field and aerial inspections, reviewing your structural design, and making upgrade, repair, and replacement recommendations.
Whether you need us for a one-time assessment or a long-term prevention plan, we can work with you.