‘Abnormal’ weather events are becoming Britain’s new normal, with serious implications for electricity distribution networks.
A new analysis by energy management and grid-edge intelligence firm VisNet has outlined how intense rainfall, sustained high temperatures and powerful winds pose a significant threat to any day-to-day activities that rely on power.
So-called ‘pre-faults’ — a sudden spike in current triggered by a breakdown of insulation on the line — are becoming more frequent due to heatwaves. However, there’s no definitive explanation for this with further investigation needed.
‘We know from conversations with electricity operators in continental Europe that in the days following extreme heat, networks can experience very significant spikes in pre-fault numbers,’ said Dr David Clements, Data Analytics Manager at EA Technology, VisNet’s parent company.
‘They could be the result of underground distribution cables expanding when the temperature rises, which then warps the cable or causes its insulation to crack,’ he continued.
While the prevalence of pre-faults is much lower in the UK compared with continental Europe, mirroring less intense heatwaves the British Isles are prone to, climate trends suggest this will become a more frequent problem in the coming decades.
More so, data on pre-faults collected by VisNet between October 2024 and March 2025 shows a significant rise in pre-faults linked to five major winter storms that hit the UK during that period. Clements and his team have identified rain permeating the ground, and seeping into the cabling through existing cracks in the lines, as the primary cause.
Backing this up, the highest concentration of pre-fault events in the six winter months occurred between 4th and 6th January. While there were no specific storms during that period, Britain was exposed to sustained precipitation, alongside excessive snowfall in northern parts of England and southern Scotland.
‘The data from the UK’s 2024/25 storm season clearly shows a one-off event like a storm causes a rise in pre-fault levels – but nowhere near to the same extent as sustained rainfall,’ said Clements. ‘Storms are more violent and inflict physical damage, but rain can also seriously disrupt electricity supplies if operators overlook their distribution network.’
‘Fault-finding used to be slow and laborious, and customers would be off supply while you were doing it,’ he added. ‘But an operator who knows more precisely where to look for a pre-fault along a particular cable saves significant time and effort in locating and then fixing it. As a result, the operator avoids penalties from the regulator for customer minutes lost.’
Image: Alice Kotlyarenko / Unsplash
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