The UK’s National Grid and The University of Manchester are working together to develop a new drone-mountable system that will allow live inspections of overhead transmission line insulators using electric field (e-field) sensor technology.

The three-year, £1.1 million innovation project, funded by Ofgem’s Network Innovation Allowance (NIA), aims to deliver an airborne system that can carry out real-time monitoring of the condition of high voltage insulators, a process that could save time and cost compared with traditional ground patrols.

Insulators, often made of glass or ceramic, produce electric fields when in operation that have distinct profiles which are altered by defects in the insulator.

 A purpose built electric field sensor system could be flown by drone near to a pylon to analyse insulators’ e-field profiles and assess their health. This would avoid the need for circuit outages, lineworkers scaling pylons, or insulator samples being sent for forensic analysis.

It is estimated that the initiative could save £2.8 million over a 15 year period through cost and resource efficiencies in transmission network monitoring.

The technology will be developed and tested in The University of Manchester’s High Voltage Laboratory, which can test up to 600 kV DC, 800 kV AC and 2MV impulse, and has been the test-bed for developing pioneering solutions such as improved designs of high voltage overhead lines.

As well as optimising the sensor hardware, the project will create digital twins for a range of insulators to define electric field profiles under different conditions, design algorithms to best assess insulators’ condition, and will re-engineer and miniaturise the tech into a drone-mountable system.

One challenge the project is aiming to overcome is to develop an algorithm to assess insulators’ condition while distinguishing between the effects that pollution can also have on the electric field.

Visual monitoring project

The project follows a separate NIA-funded project in which National Grid is trialling autonomous drones for visual monitoring of pylons and overhead lines – enabling detailed close-quarter data and imagery of equipment to be captured quickly and sent wirelessly for processing.

 Nicola Todd, head of strategy and innovation and National Grid Electricity Transmission, commented: “We’re increasingly using drones as part of our activities monitoring the condition of our transmission network, and innovations like this e-field sensing system mean there are even more exciting ways that drones could support us in keeping the grid reliable and safe in the future.”

Dr Vidyadhar Peesapati from The University of Manchester commented: “With demand increasing, we need to maximise the resilience of overhead lines, the spine of UK electricity. The ambition of this project helps us address this challenge while moving the UK one step further towards a low carbon future.”

Since 2018, National Grid has invested around £5 billion to upgrade, adapt and maintain the electricity transmission network. It plans to spend £9 billion on the network in the five years to 2026, with further multibillion-pound investments beyond that to 2030.