Storm response: how resilient are your networks?

Over the past few years, the UK has been experiencing a dramatic increase in the frequency and intensity of storms and strong winds, a trend that is increasingly linked to the broader phenomenon of climate change. This evolving climate reality presents a formidable challenge, particularly to the nation's electricity distribution networks, which are crucial for the uninterrupted functioning of daily life.

Jocelyn, Isha, Arwen, Malik are just some of the offenders. Three storms, Dudley, Eunice and Franklin were named in the one week in February 2022, as well as some of the highest wind speeds we've ever seen recorded in over 30 years.

These extreme weather events are not just abstract figures in climate studies; they have real, tangible impacts. With each passing year, the UK faces an uptick in weather-related disruptions, ranging from minor power outages to large-scale damage and outages that affect hundreds of thousands of homes and businesses. Such events highlight the vulnerability of our existing electrical infrastructure and underscore the pressing need for a strategic response. However, the challenge extends beyond merely responding to these disruptions. The key question facing industry leaders, policymakers, and stakeholders is how to proactively prepare and invest in electricity distribution networks to not only withstand these challenges but also to become more resilient while achieving our net zero goals.

The task is twofold: to ensure resilience in the face of extreme weather events and to ease the connection of more Low Carbon Technologies (LCTs) and renewable energy, such as wind turbines, electric vehicles, heat pumps and photovoltaic generation.

The impact of extreme weather events to electricity consumers

During Storm Arwen, over 1million customers lost power, 40,000 customers were off more than 3 days, and nearly 4,000 were off for longer than a week.

Following the disruption to the UK's electricity distribution caused by Storms Arwen, Malik, and Eunice, Ofgem released a review examining lessons learned and gathered feedback from affected customers, including outage prevention, communication, restoration efforts, and customer support. Although companies initiated emergency plans before the storm, these were insufficient for the scale of damage caused by Storm Arwen. The majority of network faults were due to strong winds or trees falling onto power lines. Network operators need to take actions to improve network resilience and enable quicker reconnection of customers when outages do occur.

A need was also identified for monitoring on overhead line networks, a lack of which hindered the understanding of the full scale and complexity of faults. This affected the resources deployed for repairs and customer support. It was concluded that a new ‘outcomes-focused physical resilience standard’ will be developed, which will define resilience standards in terms of the outcomes for consumers.

How do we prepare for the future?

Preparedness is the key to dealing with future extreme weather events, which are likely to become more common due to climate change. The two aims are to plan so that fewer customers are affected and lose power during storms, mainly by making the network more resilient, and also putting severe weather escalation plans in place so that when customers do go off, power can be restored quickly, while keeping affected customers informed, and helping them deal with the consequences of being left without power.

To make the network more resilient, the DNOs (Distribution Network Operators) will invest in strengthening their infrastructure to withstand extreme weather events. This includes reinforcing power lines, poles, and other critical infrastructure and performing regular maintenance and upgrades of the network in order to reduce the risk of damage.

In addition, there is a long-standing recognition from DNOs that proactively managing vegetation around power lines, can significantly reduce the risk of outages caused by falling trees and branches during storms. Downed and lowered lines from broken/snapped poles can cause safety hazards when pressure is on to re-energise lines. In addition, walking the line introduces other problems where access may be limited from trees blocking roads, and difficult access in storm conditions.

Using technology to implement advanced monitoring systems can help in the early detection of faults and quicker restoration times. These proactive technologies and remote monitoring can provide near real-time data on network performance and disruptions, as well as predict weak points developing in the network that may become an achilles heel during a storm.

The technological leap

Through an innovative partnership-driven development with Electricity North West, Kelvatek has introduced a technological solution dedicated to enhancing network reliability and helping DNO’s to respond more safely and effectively during extreme weather events. LineSIGHT, a monitoring system and fault management solution tailored for 11 kV Overhead Circuits, has emerged as a result of the successful Sentinel Network Innovation Allowance (NIA) project.

LineSIGHT addresses several challenges outlined in the OFGEM Storm Arwen report, particularly emphasising increased monitoring. The system contributes to improved network reliability and visibility by providing advanced warnings of potential faults in overhead circuits. Developed with a core commitment to health and safety, LineSIGHT enables DNOs to proactively identify weak sections of the network, allowing for strategic investments and maintenance before extreme weather events occur.

Is an integrated approach the answer?

The identification of low conductors and nested damage during the response phase to extreme weather events can be a significant reason why restoration time can extend as networks undergo assessment by field staff during the first 24/48 hours.

LineSIGHT enables the detection of damage after a circuit has been disconnected. This significantly enhances the ability to detect nested damage and low conductors that represent a safety risk that must be addressed before re-energisation. Our recent analysis of data during storm conditions highlighted that up to 75% of the time that customers were without power can be related back to nested faults.

Widespread vegetation management and pole replacement programs, though imperative, are inherently time-consuming, resource-intensive, and financially burdensome. The pragmatic solution lies in the strategic integration of these programs with advanced technological monitoring solutions.

This combined approach represents a cost-effective strategy which will complement severe weather escalation plans. By preparing the grid for extreme weather events, it ensures increased network reliability and resilience while delivering value for money to consumers.