National Grid's aerial mapping fleet safeguards Britain's power infrastructure

In a high-flying endeavour spanning over six decades, the UK’s National Grid's fleet of advanced helicopters have been diligently patrolling pylons and power lines, ensuring the health and reliability of the electricity network throughout the year.

Hovering in close proximity to high-voltage cables, the helicopter teams are tasked with monitoring thousands of towers, poles and overhead lines that distribute electricity across Britain. This critical operation, which involves flying closer to electricity infrastructure than general aviation permits, demands a safe and controlled approach by National Grid's experienced teams.

"We fly closer to electricity infrastructure than general aviation is allowed, which concentrates the mind – but it’s a safe, controlled operation that our experienced teams have been carrying out for decades," notes John Rigby, chief pilot at National Grid covering the transmission network, who has 32 years of flight experience.

With an annual coverage of more than 50,000 kilometres, National Grid's eight helicopters play a pivotal role in maintaining the transmission and distribution networks in England and Wales. Three helicopters are dedicated to monitoring 22,000 pylons, 300 substations and 7,300km of high-voltage overhead lines, while five cover the extensive 96,000km of lower-voltage overhead lines connecting to homes and businesses.

Easily recognizable in their bright yellow livery, the distribution-network helicopters operate in the Midlands, South West and South Wales, while the transmission-network helicopters, adorned in National Grid's white and blue colours, cover all of England and Wales.

Even TV personality Guy Martin joined the transmission network helicopter team for power line surveillance in Nottinghamshire, as showcased in the Channel 4 TV show "Guy Martin’s Great British Power Trip" last year.

The importance of aerial surveys

National Grid's skilled helicopter teams meticulously inspect pylons and cables for damaged parts, wear and corrosion. Beyond structural concerns, they are vigilant for other potential issues, such as vegetation encroaching on power lines. The helicopters have also been instrumental in rescuing livestock trapped in bogs and ditches by alerting local landowners.

Equipped with state-of-the-art electro-optics, including thermal imaging cameras, the teams can identify issues like 'hot spots' on overhead lines – a rare occurrence indicating an overheating joint that requires prompt attention to prevent future faults.

Aerial surveys conducted by the helicopter teams prove to be safer, more cost-effective and less resource-intensive than traditional ground inspections. The helicopters can cover vast distances and identify potential issues before they escalate, providing valuable insights for National Grid's maintenance teams.

Estimates suggest a tenfold cost saving in refurbishment and fault prevention on the high-voltage grid compared to the cost of running the transmission network's helicopters.

Thermal cameras and Lidar

While helicopters excel in covering longer distances, there are situations where they cannot be used, such as heavily built-up areas or locations with significant human or livestock presence. In such cases, National Grid deploys a fleet of uncrewed aerial vehicles (UAVs or 'drones') equipped with similar technologies. The drones offer cost and efficiency benefits, and the company is even exploring autonomous drone technology.

National Grid's helicopter teams consist of 25 full-time staff, including eight pilots and eight observers. The transmission network unit is based in Oxford, while the distribution network operation is headquartered in Bristol and includes an in-house maintenance engineering team. Rigby emphasizes the difficulty in predicting their locations due to weather dependencies, describing the team as small, flexible and nomadic.

Simon Richards, helicopter observer team manager for the distribution network, highlights the challenges of spotting issues from the air, with technology including thermal cameras and a Lidar system aiding the observers in their crucial role.

Ensuring a resilient network

National Grid's helicopter operations, coupled with nationwide ground-based patrols, are integral to maintaining the electricity network's prime condition. The multibillion-pound annual investment in infrastructure maintenance and upgrades reflects the company's commitment to ensuring a resilient network for homes and businesses in England and Wales.

With a 4,000-strong operational field staff working tirelessly across National Grid's transmission and distribution networks, the grid remains safe and reliable 365 days a year. The high-tech helicopters contribute significantly to this ongoing effort, showcasing National Grid's dedication to excellence in electricity infrastructure management.