Barry Menzies, Managing Director, MIDEL, discusses some of the world’s most extreme transformer environments and what they can teach us for everyday applications

Transformers are critical pieces of equipment, required to reliably operate in some of the world’s most extreme environments. This has led to engineering innovations to help them operate safely and effectively in a diverse range of situations, such as the use of synthetic ester fluids in place of mineral oil. Just as yesterday’s Formula One tech influences today’s commuter cars, there are lessons here we can apply to more mainstream environs in future.

And it’s vital that lessons are learned: because tomorrow’s normal may well be more extreme than today’s. As the Intergovernmental Panel on Climate Change’s latest report warns, climate change will “significantly worsen the risks of drought, floods, extreme heat and poverty”[1]. And as the frequency and severity of extreme weather events increases and urbanisation ups the stakes in terms of transformer safety risks, extreme may well become the new norm.

Frozen fluids

The world’s first liquified natural gas (LNG) project within the Arctic Circle, the $27 billion Yamal LNG facility sits on permafrost in a region where temperatures can fall past -50oC. Such extreme conditions pose many engineering challenges, not least those relating to the 20 or so power transformers charged with keeping the project running.

Here, a synthetic ester fluid with a pour point of -56oC was used to mitigate freezing and fire risks; with higher flash and fire points, an external fault would be far less likely to lead to a failure or fire, therefore reducing the chances and potential severity of an incident.

It’s not just the Arctic Circle where this is an issue; wind turbines in locations such as Canada and the North Sea also suffer from the cold. Owing to the intermittent nature of renewable energy, the risk of freezing increases when the wind isn’t blowing. Using an ester fluid with a very low pour point would then help with “cold starting” the transformer when the turbine is energised.

Running hot

Conversely, synthetic esters offer equal advantages in the opposite extreme. Consider Kuwait, where the mercury behaves quite differently than in Yamal, with ambient air temperatures rarely dipping below 50oC in the summer months.

In practice, once air has been taken into the transformer, it is probably closer to 70oC. As such, you have assets running very close to their maximum permitted temperature. If any faults occur that restrict liquid flow – causing hot spots in the transformer – then localised overheating can happen.

That’s when mineral oil transformers explode and burn – a phenomenon known in Kuwait as ‘popping’. With a fire point considerably exceeding that of mineral oil, synthetic esters again mitigate the safety and financial risk of failure. However, there are also additional benefits in terms of reduced maintenance costs, as the extreme heat accelerates chemical reactions that cause degradation. The use of an ester fluid could potentially compound cost savings on auxiliary cooling equipment that would otherwise be needed. In the midst of this extreme environment, the Kuwaitis have embraced risk mitigation and adopted synthetic ester fluids nationally.

An extreme future

Climate change is upon us and the experts tell us to expect more extreme weather events. But for many, everyday environments will become more extreme too. The impacts of climate change will not be uniform but hurricanes are predicted to be more intense, droughts more severe and flooding more frequent. As the extreme becomes more everyday and the everyday more extreme, today’s best practice will be tomorrow’s standard practice.

[1] https://www.theguardian.com/environment/2018/oct/08/global-warming-must-not-exceed-15c-warns-landmark-un-report