National Grid’s eyes in the sky

National Grid’s fleet of high-tech helicopters is patrolling pylons and power lines across the country – a high wire act they have been performing for over half a century to keep the electricity network in good health all year round.

Hovering near the high voltage cables that carry power around Britain is all in a day’s work for the helicopter teams, who are closely monitoring the condition of the thousands of towers, poles and cables that get electricity to where it’s needed.

With so much critical infrastructure being monitored each year ahead of winter, the aircraft collectively clock up around 4,700 hours of flight time and cover 32,000 miles of network annually on their patrols. It’s a job the helicopter units have been doing since the 1960s when the Central Electricity Generating Board (CEGB) first took to the air.

Today the company operates eight helicopters across its networks – three to monitor the 22,000 pylons, 300 substations and 4,300 miles of high voltage overhead line that make up the transmission network in England and Wales; and five to cover the 60,000 miles of lower voltage overhead line on its distribution network that connects to homes and businesses.

You can’t miss them – the distribution network helicopters operating in the Midlands, South West and South Wales are bright yellow, and the transmission network helicopters covering all of England and Wales are in National Grid’s white and blue livery.

 What are the helicopters looking for?

A skilled team in each helicopter is looking for damaged parts, wear and corrosion on the pylons and cables – but they’re also looking for other potential issues in the area like vegetation growing too close to a line.

They have even helped rescue livestock they have spotted stuck in bogs and ditches, by calling it in to local landowners.

An experienced pilot keeps the helicopter’s movements steady while specialist observers gather the imagery needed by network engineers – so you might see one of the aircraft flying close to an electricity line briefly before moving on.

The teams also have state-of-the-art electro-optics such as thermal imaging cameras at their fingertips to help identify issues like ‘hot spots’ on overhead lines – a rare occurrence but an indication of an overheating joint that will need fixing to avoid future faults.

 Why are the helicopter checks important?

Aerial surveys are safer, more cost-effective and less resource-intensive than climbing the entire network of pylons or inspecting the wood poles by foot. It might take three lineworkers on the ground several days to carry out inspections on a handful of towers that would take an airborne observer just hours to inspect.

Crucially the helicopter teams’ work can spot potential issues before they go wrong, feeding back insight for National Grid’s overhead line maintenance teams to take action on if needed.

It is estimated that for the cost of running the transmission network’s helicopters, there’s a tenfold cost saving in refurbishment and fault prevention on the high voltage grid.

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