Sep 2012
Electricity Transmission
Fibre-optic Acoustic Monitoring
Sep 2012
May 2015
National Grid Electricity Transmission
Andrew Roxborough
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Network Innovation Allowance
Comms & IT
Fibre optics are currently extensively used in communications, however they have many other uses. National Grid already uses them in cable tunnels to monitor the temperature of the cables.

Fibre optics are currently extensively used in communications, however they have many other uses. Fibre optics have also been used to monitor areas acoustically mainly by security firms, but are also used extensively in the monitoring of pipelines. This same technology can, not only be used for security but, also for the monitoring of assets and locating personnel.

This acoustic fibre technology uses one of two systems, optical time domain reflectometry (OTDR) and interferometry.

Interferometry looks at the interference the fibre introduces to laser light shone through the fibre. This system acts as a single point sensor and is extremely sensitive. OTDR, or optical time domain reflectometry, monitors the light reflected back to the source when a laser is shone into the fibre. By pulsing the laser, location of the vibration detected can be established. This system is less sensitive than interferometry however it is useful for monitoring a large area as fibres as long as 20-30km can be turned into thousands of individual sections monitored by the system.

The key objective for this project are:-

o Understand the benefits of monitoring National Grid site and assets acoustically using fibre optics. o Undertake trials of current acoustic fibre technologies and evaluate their usefulness within National Grid

o Investigate possible future applications of current acoustic fibre technologies.
o Investigate future acoustic technologies.
o Collaborate with domestic and overseas companies with similar interests in acoustic sensing using fibre optics.

o Derive strategy for further R&D or application going forward 

This project will be successful if we either prove the use of Acoustic monitoring on National Grid Electricity Transmission assets, or if we understand the reasons why it has not worked.