Climate change
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lightning strikes. These pose a uniquely high risk due to both the turbines’ exposed locations and their height: turbines are now being built in excess of 450ft. Even a small fire can accelerate quickly in a nacelle that comprises highly flammable resin fibreglass. Internal insulation, which can become contaminated by oil deposits, further adds to the fuel load.
Redesigning the turbines to reduce the fuel load inside the nacelle is one step to reduce fire risk. In addition, any maintenance and repair activities that involve ‘hot work’ inside the nacelle could be avoided. It has also been suggested that condition monitoring systems should be implemented and maintenance checks completed regularly. As a final step, automatic fire detection and
suppression systems can be incorporated to further protect the nacelle. This presents a unique challenge, as dust, vibration and temperature fluctuations can all interfere with reliable operation.
Detection and suppression
Several types of fire detection are available. Smoke detection or air sampling systems can be successful in detecting the early stages of a fire, but may be rendered ineffective by air flows and environment. Alternatively, traditional linear heat and fusible link detection systems aren’t affected by air and dust, but are potentially electrically conductive. All these systems will fail if the external power or battery backup fails. Then there are the fire suppression agents.
Compressed air foam systems and water mist are potentially corrosive and can be ineffective on energised electrical components. Carbon dioxide
systems aren’t ideal because, due to the CO2 displacing the oxygen in the event of a discharge, the fire suppression system has to be ‘locked out’ any time personnel are present in the nacelle. In such a situation where people are working at height, this is a major safety concern. In the cramped environment within the
nacelle, a problem can also be posed by the weight of these technologies and the space required to store them. The most common solution today overcomes these drawbacks by providing component level automatic systems that offer both fire detection and suppression in a single package. Designed to detect a small fire in or around a critical component, they dramatically improve the response time and reliability, while reducing the size of the system required. They use clean agent fire suppression
technology involving a non conductive gas, which leaves no residue following a discharge, requires no clean up, and in small volumes does not present a hazard to personnel. The presence of an automatic fire detection and suppression system such as Firetrace offers 24/7 reliability and unsupervised protection to quickly address a growing fire and limit its damage. And yet, despite the availability of affordable fire suppression methods, thousands of wind turbines are still being installed without adequate fire protection, and entirely preventable wind turbine fires continue to occur.
Legislation growth
There has, however, been increasing momentum over the past few years for legislation requiring fire suppression on new wind farms. A growing
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