The UK intends to have many more expensive wind turbines scattered all over the place, often in remote areas or offshore. How best to prevent, or deal with, fires is a question that can’t be swept under the carpet to maintain a false image.
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Why the wind industry cannot afford the financial and reputational damage that even a single turbine fire can bring.
The wind industry has underestimated fire risk for decades, says Angela Krcmar @ Power Engineering International.
Even now, statistics around fire losses are based on estimates and incomplete datasets.
For a time, the industry could get away with not fully managing fire risk, as the size and number of assets per owner were low enough for many to not experience a fire in their portfolio.
However, as turbines begin to scale up and wind takes on a greater share of national energy mixes across Europe and North America, the industry cannot afford the financial and reputational damage that even a single turbine fire can bring.
Wind turbines catch fire primarily due to electrical or mechanical faults leading to ignition which spreads to the surrounding plastics and fibreglass nacelle.
Turbine fires tend to originate in the nacelle at one of three points of ignition – converter and capacitor cabinets, transformer or the brake.
Converter and capacitor cabinets are necessary for the wind turbine to translate the variable frequency and amplitude of generated energy into a constant frequency and voltage that can be fed into the grid.
However, an electrical fault at these components can produce arc flashes or sparks, which can surround plastics in the cabinet and result in a fire. Transformers, which similarly convert energy into an appropriate voltage for the grid, can also be a point of ignition due to electrical faults.
Nacelle brakes are utilised in an emergency along with blades pitching to stop the turbine blades from spinning in seconds. This generates an enormous amount of friction and heat, and a mechanical fault at the nacelle brake can easily result in a fire.
Financial risk of fire
The rate of fires has remained consistent over the past decade according to available data – typically one in every 2000 turbines will burn down every year.
While technologies which are less susceptible to fire such as electric braking systems have been developed, many of the key ignition points are necessary for electricity generation and as such, cannot be designed out of the turbine.
While the frequency of fires has remained constant over the years, the financial risk of fire has increased with the size and complexity of turbines.
As turbines are getting increasingly bigger and therefore more expensive, a single fire can have a much greater impact.
Full article here.
via Tallbloke’s Talkshop
October 31, 2020 at 12:27PM