Electricity North West targets improved safety and resilience with LineSIGHT

The impact of Storm Arwen

In November 2021, Storm Arwen brought chaos to the UK. The fallout from the extratropical cyclone included three fatalities due to falling trees, rail passengers stuck on trains overnight, snow across the Pennines, and vehicles overturned by high winds.

Then there’s the serious matter of the one million homes that experienced a loss of power because of strong winds, or trees falling on overhead lines, with more than 100,000 experiencing an outage that lasted several days.

Storm Arwen was the most powerful winter storm of the past 10 years. Analysis of the disruption found the duration of the outages was due to sensors on overhead lines failing to detect fresh damage because they were without power while the initial faults were repaired. There were also difficulties coordinating and resourcing field teams in major storm conditions.

People were without power for so long because networks would get a report of an initial fault, teams would address it, and in the intervening period the storm would inflict even more damage while circuits were de-energised. Sensors on the network didn’t reflect the damage because there was no power flowing through them.

The critical role of LineSIGHT

Enter LineSIGHT, Kelvatek’s monitoring and fault management system for overhead lines, which is being rolled out by the regulator and Electricity North West (ENWL). The technology offers the capability to accurately locate major outage issues such as faults, downed lines, and low-hanging conductors.

Paul Killilea, asset and investment director at ENWL, explains more. “When there are storm conditions and severe weather, the overhead line network can fault due to trees falling, or heavy wind causing clashing of conductors, and it can be quite devastating. Storm Arwen demonstrated that.”

ENWL has a complicated network. It includes 160,000 wood poles across 1,000 circuits. An individual circuit could be tens of kilometres long. Some parts of the network are in rural or mountainous areas where reporting of damage by the public is unlikely.

That’s why the DNO has a sophisticated digital network management system that automatically starts to restore supplies in the event of a fault, opening and closing circuits to determine where it is.

But that could still be in the range of several kilometres of line, Killilea explains. “We also check all customer calls that come in and group the calls and faults to try and pinpoint an area.” Patrolling the line to look for an exact location could take several hours, he adds.

The key benefit of LineSIGHT’s predecessor project Sentinel was the ability to locate faults within plus or minus 500 metres. “That means with we were able to target several spans’ length of line with resources.

“With LineSIGHT we are now able to pinpoint faults within 250 metres or less, so it’s a much more accurate and efficient way of locating a fault and starting the restoration and repair process.”

LineSIGHT can also sense very small fluctuations in voltage and current which indicate a piece of equipment such as an insulator is starting to fail. “This will mean that we can proactively repair rather than wait for a complete fault and the disruption it causes. Our existing capability isn’t sensitive enough to detect some of the fault conditions LineSIGHT can find.”

Because LineSIGHT is capable of sensing that there is something unusual on a circuit before a fault causes an outage, it will help enable predictive maintenance, Killilea explains. “We can be proactive: looking for the fault that hasn’t occurred yet.”

Other DNOs are now planning to install LineSIGHT, he says, with some of these deployments being funded through Storm Arwen-related allowances.

Meanwhile, ENWL is also using Kelvatek technology on low-voltage networks to improve storm response. Kelvatek’s PERCH solution (pole-mounted reclosers) sits on low-voltage lines and detects faults that cause fuses to blow and interrupt supply, and then will attempt to restore power.

This is particularly useful because faults are often transient in storm conditions. Debris or birds can strike the line, for example, and trip out the circuit. The network is seeking a wider roll-out of PERCH on its low-voltage networks, also as part of the Storm Arwen re-opener. “Restoring faults is a very resource-intensive process, so PERCH is a big win,” Killilea says.

For its part, LineSIGHT currently covers 23 circuits at ENWL. This has enabled the detection of many incidents including broken insulators, de-stranded conductors, and locations with burn damage, and provided the opportunity to make faster repairs. This is making the network more resilient and efficient, resulting in easier maintenance.

“But ultimately, for us, with LineSIGHT, the safety case is everything,” Killilea says.

Advanced data management

Robert Friel, a chartered electrical engineer who runs Apteno Consulting, and was formerly emergency planning manager for EDF Energy Networks, explains that a number of DNOs have seen incidents where line conductors on the ground have caused fatalities. “It’s mercifully rare, but it happens. The resistance on the ground is often high, which means the circuit doesn’t always trip.

“The ability to monitor those faults that could be a danger to life is vital, and you couldn’t always do it before. Storms generate reputational damage, but LineSIGHT will also help networks fulfil their responsibilities under the Electricity, Safety, Quality and Continuity Regulations.

“That’s why it’s so important.”

The combination of LineSIGHT with Kelvatek’s Sapient data management platform provides an overview of the topology of the network that helps make it safer, Killilea adds.

Sapient receives a host of data points from sensors in the field and monitors the health of the network. It features algorithms that analyse network conditions based on its knowledge of how the network is structured. The platform is also integrated with the ENW network management system, so it doesn’t record intentional changes to the network configuration as faults.

The more fault detection and resolution is automated and digitalised, the better, Killilea explains. In storm conditions and high winds, people can’t work at height. “Systems that can re-close automatically and get power systems back on without human intervention are ideal.

“And automating as much as you can around the fault means less disruption for customers.”

As climate change worsens and extreme weather becomes more frequent, this resiliency will be crucial. “In 2023, we had a 20% increase in high-voltage faults on our network. It was a heavy year for us.

“But overall, our network performed at the best level it’s ever performed at, and that’s because we have invested in technologies and integrated them to our digitised network management system.”